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15 September 2022, Volume 43 Issue 17
Intestinal Flora
Mouse β-Defensin 14-Expressing Lactiplantibacillus plantarum Attenuates Acute Colitis in Mice
CHEN Xiaopei, TIAN Haizhi, REN Zhengnan, PAN Lilong, SUN Jia
2022, 43(17):  1-11.  doi:10.7506/spkx1002-6630-20220509-110
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The antimicrobial peptide β-defensin also has an immunomodulatory effect. It plays an important role in maintaining intestinal homeostasis. This study aimed to investigate the role of mouse β-defensin 14 (mBD14) in inflammatory bowel disease (IBD). Lactiplantibacillus plantarum was used as a carrier for targeted delivery of mBD14 into the mouse intestine by genetic engineering technology. Meanwhile, the effect of the bacterium on acute colitis induced by dextran sulfate sodium (DSS) in mice was assessed. The results showed that mBD14-expressing Lactiplantibacillus plantarum alleviated the symptoms of colitis. Moreover, the bacterium modulated the gut microbiota, protected intestinal barrier function, attenuated the expression of pro-inflammatory cytokines and inhibited the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) and downstream inflammatory pathways. Thus, the current study reveals a protective effect of mBD14-expressing Lactiplantibacillus plantarum against DSS-induced colitis, which provides a rationale for the development of prophylactic strategies based on probiotics and antimicrobial peptides for the prevention of IBD.
Synergistic Effect of Lotus Seed Resistant Starch and Sodium Lactate on Intestinal Flora and Metabolism in Rats
SHANG Weixuan, LIU Lu, LEI Suzhen, ZHENG Baodong, ZHANG Yi, ZENG Hongliang
2022, 43(17):  12-23.  doi:10.7506/spkx1002-6630-20220419-239
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In order to study the synergistic effects of lotus seed resistant starch (LRS) as a prebiotic and sodium lactate (SL) as a postbiotic on the intestinal flora and metabolic profile of rats, 24 male SD rats were randomly divided into normal control (NC), LRS, SL, and LRS + SL groups. After four weeks of oral administration, the diversity of intestinal flora and differential metabolites were analyzed by high-throughput gene sequencing and non-targeted metabolomics, respectively. The results showed that LRS, SL and their combination could increase the richness of intestinal flora. Compared with the NC group, the relative abundance of Lachnospiraceae_NK4A136_group was increased, while the relative abundance of Coriobacteriaeae_UCG-002 and Enterrhabdus in the small intestine of rats was decreased in the LRS group; in the SL group, the relative abundance of Lactococcus and unclassified_f__Micrococcaceae was decreased increased, respectively; in the LRS + SL group, the relative abundance of unclassified_f__Ruminococcaceae and Lachnospiraceae_NK4A136 was increased, whereas the relative abundance of Vagococcus and Allobaculum was decreased. Compared with the LRS and SL groups, the relative abundance of Allobaculum was decreased, while the relative abundance of unclassified_f__Ruminocaceae was increased. The non-targeted metabolomic analysis showed that the levels of (R)-lipoic acid, α-curcumin, ginkgolide A, cervonoyl ethanolamide and steroid hormones in the small intestine of rats in the LRS group were up-regulated, while the levels of LysoPC(17:0) and L-serine were down-regulated compared with the NC group, and there were significant differences in steroid hormone metabolic pathways between the two groups. In the SL group, cervonoyl ethanolamide was up-regulated, and the metabolic pathways of steroid hormones and bile acids changed significantly. In the LRS + SL group, pantothenic acid was up-regulated, whereas LysoPC(17:0) was down-regulated, and amino acid metabolic pathways changed significantly. There were significant differences in metabolic pathways of lipid, bioactive substances and vitamin between the LRS + SL group and the LRS and SL groups. Intervention with LRS and SL could optimize the structure of intestinal flora and inhibit the reproduction of potentially harmful bacteria, thereby promoting the increase of potentially beneficial metabolites. The combination of LRS and SL was more effective in increasing the diversity of intestinal flora, regulating vitamin metabolism, amino acid metabolism and lipid metabolism, and enhancing the defense system in the body. These results will provide a theoretical basis for studies on the synergistic effects of prebiotics and postbiotics.
Recent Advances in Multi-scale Structural Characteristics and Intestinal Flora-Regulatory Effect of Different Types of Resistant Starch
ZHANG Jinxiu, HU Xinzhong, MA Zhen
2022, 43(17):  24-35.  doi:10.7506/spkx1002-6630-20220401-007
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In recent years, resistant starch (RS) has been extensively studied due to its important role in improving intestinal flora, regulating glucose and lipid metabolism and maintaining body health. Different types of RS have specific effects on intestinal flora and thus may exhibit different physiological functions. In this paper, the multi-scale structural properties of different types of RS are described, and the effects of different types of RS on intestinal flora, short-chain fatty acids, intestinal health and glucolipid metabolism are compared. The potential correlation between the types of RS and the intestinal flora-regulatory effect of RS is comprehensively reviewed. This review could provide useful information for individual design of RS and precise regulation of intestinal flora.
Basic Research
Effect of Hypoxia-Inducible Factor 1 on the Contents of Energy Metabolites and Meat Color in the Early Aging Period of Tan Sheep Meat
JI Chen, YANG Bo, LUO Ruiming, LIU Jijuan
2022, 43(17):  36-41.  doi:10.7506/spkx1002-6630-20210719-219
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This study was designed to clarify the changes in the expression level of hypoxia-inducible factor 1 (HIF-1) and its effects on the activity of triose-phosphate isomerase (TPI), the contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP), and meat quality traits in Tan sheep meat during a 48-hours postmortem aging period. Results indicated that the expression level of HIF-1 increased significantly between 2 and 24 h, and then decreased. The activity of TPI increased significantly, reaching a maximum value at 6 h, then significantly decreased until 48 h. The contents of ATP, ADP, and AMP significantly decreased with increasing aging time, while muscle pH significantly decreased (P < 0.05). The color values of L*, a*, and b* were significantly increased with increasing aging time. Correlation analysis indicated that the expression level of HIF-1 was correlated with meat quality indicators, TPI activity, and the contents of ATP, ADP and AMP significantly (P < 0.05, P < 0.01). It might be speculated that postmortem hypoxia could induce a rapid increase in the expression level of HIF-1 within 6 h postmortem, and the transfer of the HIF-1 complex to the nucleus to bind with glycolytic genes, thereby promoting the expression of glycolysis-related genes, enhancing postmortem glycolysis, leading to increased activity of glycolysis-related enzymes and decreased muscle pH. To sum up, HIF-1 can affect meat color by regulating postmortem muscle glycolysis and pH.
Effects of Different Extraction Processes on Structural Characteristic and Immunomodulatory Activity of Pleurotus eryngii Polysaccharide
MA Gaoxing, WANG Han, YANG Wenjian, SU Anxiang, PEI Fei, MA Ning, HU Qiuhui
2022, 43(17):  42-49.  doi:10.7506/spkx1002-6630-20220316-196
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Hot water extraction (H), ultrasonic extraction (U) or ultrasonic-assisted hot water extraction (U + H) was used to extract polysaccharides from Pleurotus eryngii, which were then evaluated for physicochemical and structural characteristics and immunomodulatory activity. Results indicated that all three polysaccharides showed absorption peaks characteristic of polysaccharides. The polysaccharide prepared by ultrasonic extraction (U) was composed of mannose, glucose, galactose, xylose and fucose in a molar ratio of 8.60 : 80.90 : 7.41 : 2.68 : 0.57. The polysaccharide obtained by hot water extraction (H) was composed of mannose, glucose, galactose, xylose and fucose in a molar ratio of 9.36 : 79.72 : 8.18 : 2.60 : 0.42. The polysaccharide obtained by ultrasonic-assisted hot water extraction (U + H) was composed of mannose, glucose, galactose, xylose and fucose in a molar ratio of 6.75 : 82.66 : 7.14 : 2.30 : 1.12. The molecular mass distribution of U consisted of 13 152 (83.61%), 281 (3.02%), and 53 kDa (13.37%). The molecular mass distribution of H consisted of 10 232 (93.15%), 281 (1.94%) and 61 kDa (4.90%). The molecular mass distribution of U + H consisted of 10 471 (98.59%), and 60 kDa (1.40%). The results of cell counting kit-8 (CCK-8) showed that the polysaccharide extracted by ultrasonic extraction at low concentrations of 5 and 10 μg/mL had a slightly toxic effect due to the degradation of large molecular mass polysaccharide fractions, while the other concentrations of U and all concentrations of H and U + H had no significant toxicity to macrophages. Neutral red test results showed that the three polysaccharides could enhance the phagocytic activity of macrophages significantly but differently (P < 0.05). The phagocytic rate of macrophages treated with U was 193.45% compared to 163.64% and 187.62% with H and U + H, respectively. This study provides a theoretical foundation for the directional preparation of P. eryngii polysaccharides with specific functional activities.
Deep Network Based Prediction Model for Heavy Metal Cadmium Content in Wheat Processing Chain
JIN Xuebo, ZHANG Jiashuai, GUO Tianyang, WANG Xiaoyi, SU Tingli, LAI Yanqun, KONG Jianlei, BAI Yuting
2022, 43(17):  50-55.  doi:10.7506/spkx1002-6630-20210717-194
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Cadmium is considered one of the most harmful heavy metals because of its wide range of dangerous contamination, high toxicity, and easy invasion. Long-term intake of excessive cadmium can cause many diseases including cancers. Cadmium content prediction in the wheat processing chain is of great practical importance for developing countermeasures to reduce its hazards. In this paper, we proposed a deep learning prediction model using the regularization method to address the problem that the data of cadmium content in the wheat processing chain contain strong nonlinear and random noises, which leads to poor fitness of the traditional model. Firstly, a gated recurrent unit (GRU) was used to build the deep learning prediction model. Secondly, the loss function of the model was modified using the regularization method to reduce the impact of noise on the prediction performance of the model by adding a noise penalty term to fade out the noise fit of the model during training. Finally, a Bayesian optimization method was used to select the hyperparameters to ensure that the model could accurately predict the cadmium content at each stage of the wheat processing chain. The prediction results show that flour made from wheat grains with a cadmium content less than 0.1 mg/kg can basically meet the requirements of the national standard (GB 2762-2017).
Effects of Thawing Methods on Water-Holding Capacity and Texture of Frozen Farmed Takifugu obscurus
QIU Zehui, ZHENG Yao, WANG Xichang
2022, 43(17):  56-63.  doi:10.7506/spkx1002-6630-20210531-358
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The effects of four thawing methods (low-temperature air thawing, room temperature thawing, flowing water thawing and ultrasonic thawing) on the water-holding capacity and texture of the dorsal muscle of frozen farmed Takifugu obscurus were investigated, and the underlying mechanism was analyzed by evaluating the changes in the physicochemical properties of myofibrillar and sarcoplasmic proteins. The results showed that the low-temperature air thawing (210 min) group had better water-holding capacity and texture, higher sensory scores, and the most complete muscle structure. The thawing loss rate of the ultrasonic thawing group (10 min) was the highest (12.34%). The texture of the flowing water (22 min) and room temperature thawing (120 min) groups were poor with a greater degree of muscle tissue destruction. Moreover, the degree of protein denaturation was lower in the low-temperature air thawing group than in the other three groups. Partial least squares regression (PLS-R) analysis result indicated that protein denaturation would destroy the texture and sensory properties, but have little effect on the thawing loss. Generally speaking, although low-temperature air thawing was the most time consuming, it is an ideal way to maintain the water-holding capacity and texture of cultured Takifugu obscurus meat to the greatest extent, with the least damage to muscle fibers and proteins.
Antibacterial Activity and Mechanism of Green Huajiao (Zanthoxylum schinifolium) Essential Oil against Bacillus cereus
ZHAO Chi, DONG Ling, ZHANG Fengju, CHEN Shanbo, HU Wen, ZHAO Yuejun, HUANG Zhibiao, ZHU Yongqing, LI Zhihua
2022, 43(17):  64-73.  doi:10.7506/spkx1002-6630-20210906-072
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Green huajiao (Zanthoxylum schinifolium) essential oil (GHJEO) is a natural medicinal and flavoring essential oil. GHJEO has been reported to show good antibacterial activity as a promising alternative to chemical food preservatives in the food industry. However, the antibacterial mechanism of GHJEO has rarely been reported. In this study, we analyzed the antibacterial mechanism of GHJEO against Bacillus cereus at the physicochemical, morphological and metabolic levels. GHJEO contained many previously reported antibacterial components. The MIC and MBC of GHJEO against B. cereus were determined to be 2.0 and 4.0 mg/mL, respectively. We found that GHJEO could destroy the cell wall and membrane of Bacillus cereus, causing cytoplasmic leakage. In addition, GHJEO at a subinhibitory concentration (0.5 MIC) could cause significant metabolic changes of B. cereus. Further bioinformatics analysis revealed that GHJEO could cause cell membrane damage, energy metabolism disorders, and amino acid metabolism disorders. The results of this study may be beneficial for the development and application of GHJEO in food safety.
Autolysis Alters the in Vitro Antioxidant and Antitumor Activities of Agaricus bisporus Polysaccharides
SUN Xiaoyan, GUO Hui, YU Juntong, ZHANG Guangwen, PENG Xichun
2022, 43(17):  74-83.  doi:10.7506/spkx1002-6630-20210424-344
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This study aimed to investigate the effect of Agaricus bisporus autolysis on the molecular mass, in vitro antioxidant and antitumor activities of Agaricus bisporus polysaccharides (ABP). After different periods of Agaricus bisporus autolysis at different temperatures, ABP were extracted and fractionated to obtain fractions with strong antioxidant and antitumor activities, and the molecular mass and monosaccharide composition of the bioactive fractions were determined. The results showed that ABP were degraded to medium-molecular-mass polysaccharides due to Agaricus bisporus autolysis. Agaricus bisporus autolysis enhanced the antioxidant and antitumor activities of low-molecular-mass polysaccharides. The molecular mass of the ABP fraction with the best antioxidant and antitumor activities was 619.72 Da and monosaccharide composition analysis showed that it was mainly composed of glucose, galactose, and rhamnose.
Molecular Characteristics, in Vitro Antioxidant and Immunological Activities of High-Methoxy Pectin-Phenolic Acid Derivatives from Passion Fruit
GAO Fan, DING Ning, AI Lianzhong, LAI Phoency, ZHANG Hui, SONG Zibo
2022, 43(17):  84-94.  doi:10.7506/spkx1002-6630-20210706-052
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This study aims to investigate the molecular characteristics, spectral characteristics, and in vitro antioxidant and immunomodulatory activities of laccase-mediated passion fruit high-methoxyl pectin (PFP) derivatives with ferulic acid (FA) or p-coumaric acid (CA) in comparison with those of its derivative with ascorbic acid (PFP-L-VC) (without linkage with quinones formed from phenolic oxidation). The contents of total phenolic compounds (TPC) of the derivatives PFP-L-FA and PFP-L-CA were significantly higher than those of PFP and PFP-L-VC (P < 0.05). The weight-average molecular mass (mw) of PFP-L-CA increased to 256.5 kDa, while the mw of PFP-L-FA did not change obviously, and the mw of PFP-L-VC decreased compared with that of PFP (190.5 kDa). Both phenolic acid derivatives showed significantly smaller Mark-Houwink-Sakurada exponent (α), radius of gyration (Rg), and anisotropic conformation parameter (ρ), implying a random-coil, flexible, dense, spherical conformation. Fourier transform infrared spectra displayed that the peak area at 1 625 cm-1 (free carboxyl group) decreased and the peak area at 1 739 cm-1 (esterified carboxyl group) increased, suggesting the formation of ester linkages between PFP’s carboxyl groups and phenolic acids. Compared with PFP, both PFP-phenolic acid derivatives had significantly improved in vitro antioxidant activities (in scavenging hydroxyl and superoxide anion radical, chelating Fe2+ and reducing power) and immunological activities (macrophage proliferation rate, NO release and neutral red phagocytosis), which could stimulate NO release from mouse macrophages and neutral red phagocytosis by mouse macrophages. In terms of scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, PFP-L-CA was superior to PFP-L-FA and PFP-L-VC, which may be related to phenolic acid structure. This study has demonstrated that phenolic acids can endow PFP derivatives with improved in vitro antioxidant and immunomodulatory activities, which will provide a theoretical basis for the application of phenolic acid-conjugated pectin as food gums and dietary fibers.
Mass Transfer Kinetics of Osmotic Dehydration of Strawberries with Various Small-Molecule Sugars and Their Effect on the Quality of Freeze-Dried Strawberries
LI Zhuohao, BI Jinfeng, YI Jianyong, GUO Yuxia, LI Jun, ZHU Fengmei
2022, 43(17):  95-104.  doi:10.7506/spkx1002-6630-20210708-082
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In order to systematically understand the osmotic dehydration behavior of strawberries with different small-molecule sugars, especially oligosaccharides and sugar alcohols, as well as their effect on the quality of freeze-dried strawberries, the osmotic dehydration kinetics of strawberries with 10 common small-molecule sugars (at a concentration of 40 °Brix) was fitted using two mathematical models and the physicochemical properties of freeze-dried strawberries obtained after osmotic dehydration were characterized. The results showed that the Weibull model was more suitable for describing the solid gain (SG) of osmotically dehydrated strawberries, while the Peleg model could better describe the water loss (WL). The SG of strawberries differed depending on the sugars used. More specifically, the SG of strawberries was 6.84 g/100 g after osmotic dehydration with sorbitol, which was 6.16 times higher than that with isomalt oligosaccharides. In addition, after osmotic dehydration, the hardness of strawberries was enhanced by 94.58% to 223.23%; the crispness of strawberries dehydrated with glucose, fructose and sorbitol was decreased by 16.70%, 20.74% and 41.45%, respectively. The texture characteristics of strawberries dehydrated with fructooligosaccharide were the closest to those with sucrose. Overall, considering the osmotic efficiency, sensory and nutritional quality and production cost, fructooligosaccharide seems to be a superior solute for osmotic dehydration of fruits and vegetables compared to sucrose.
Food Engineering
Effect of Combined Cold Plasma-Activated Water and Dielectric Barrier Discharge Treatment on the Sterilization and Quality of Strawberry
ZHAO Ying, YAN Longfei, YAN Wenjing, ZHANG Jianhao
2022, 43(17):  105-116.  doi:10.7506/spkx1002-6630-20210830-393
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Postharvest microbial contamination of strawberries has become a topical issue for safety and quality control in the logistics process. In this study, the effect of combined cold plasma-activated water (PAW) and dielectric barrier discharge (DBD) treatment on the sterilization and quality of strawberries was explored. One-factor-at-a-time experiments were carried out to investigate the effect of PAW preparation time, salicylic acid concentration, and soaking time as well as DBD working voltage, time and frequency on the total bacterial count (TBC) on the surface of strawberries. The significant variables affecting the response variable were determined using Plackett-Burman (PB) design and were optimized using Box-Behnken design. Results showed that the TBC on the surface of strawberries decreased first and then leveled off with increasing PAW preparation time and salicylic acid concentration, while it continuously decreased with increasing DBD working voltage and time. Nevertheless, when DBD working voltage and time exceeded 60 kV and 150 s, respectively, the appearance of fruit color was faded and even damaged. Soaking time and working frequency had no significant effect on the TBC (P > 0.05). Besides, salicylic acid concentration, PAW preparation time and DBD working voltage were the significant variables affecting the TBC (P < 0.001), ranked in decreasing order of importance. The critical values of salicylic acid concentration and DBD working voltage both showed a linear downward trend with PAW preparation time. The optimum values of PAW preparation time, salicylic acid concentration and DBD working voltage were found to be 96 s, 1.1 mmol/L and 46 kV, respectively. Under these conditions, the TBC decreased from 3.64 (lg (CFU/g)) to 0.83 (lg (CFU/g)) and the sterilization rate was 99.8%. The combined treatment could obviously inhibit the growth of microorganisms at 20 ℃ for 8 days, effectively maintain the quality and extend the shelf life of strawberries .
Effect of Ultrasonic-Assisted Sugar Osmotic Pretreatment on Quality and Hygroscopicity of Vacuum Freeze-Dried Peach Chips
CHEN Lamei, JIN Xin, BI Jinfeng, HU Lina, QIU Yang, LÜ Jian
2022, 43(17):  117-123.  doi:10.7506/spkx1002-6630-20210507-053
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To investigate the effects of ultrasound-assisted sugar pretreatment on the quality and hygroscopicity of vacuum freeze-dried peach chips, we compared the moisture loss rate and solid yield of peach slices after ultrasound-assisted osmosis in four sugar solutions (sucrose, maltose, glucose and oligoisomaltose) as well as the microstructure, texture (hardness and brittleness), hygroscopicity and glass transition temperature of the resultant peach chips. The results showed that ultrasound-assisted osmosis increased the water loss rate and solid gain of peach slices, resulted in denser pores, cell rupture and structural collapse, and significantly increased the hardness of peach chips compared to the control group (P < 0.05). In addition, ultrasound-assisted osmosis reduced the hygroscopicity of peach chips, and the percentages of mass change after reaching the hygroscopic equilibrium with increasing relative humidity from 0 to 90% ranged from 55.16% to 59.63%, compared to 61.43% for the control group. Ultrasound-assisted osmosis increased the glass transition temperature to 64.27 ℃ compared to the control group (52.37 ℃). In conclusion, ultrasonic-assisted osmotic treatments with sugar solutions have significant influence on the product quality while reducing the hygroscopicity and changing the glass transition temperature of peach chips. The results of this study provide a technical reference for improving the quality of dried peach chips.
Composition and Gel Properties of Protein Isolate Obtained from Chicken Ribs by Ultrasound-Aided Isoelectric Solubilization/Precipitation
TIAN Jinhe, WANG Yanjie, ZHOU Yaqi, LIN Fang, WANG Shuli, WANG Liping
2022, 43(17):  124-130.  doi:10.7506/spkx1002-6630-20220211-067
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High-intensity ultrasound (HIU)-aided isoelectric solubilization/precipitation (ISP) was applied to prepare protein isolate (PI) from chicken ribs, and the composition and gel properties of the PI were evaluated. The results showed that myofibrillar proteins were the major components of the PI. Acid treatment induced the degradation of myosin heavy chain in the PI, which could be evidently lessened by HIU. Alkaline treatment did not affect heat-induced gel properties (hardness, cooking loss and centrifugal loss) of the PI as compared to the control group. Gel properties of the PI prepared under acid conditions were significantly (P < 0.05) worse than those under alkaline conditions. HIU significantly increased the hardness and springiness, and reduced the cooking loss and centrifugal loss of heat-induced gels of the PI by acid ISP method (P < 0.05). The whiteness of all PI gels was significantly lower than that of the control gel (P < 0.05). The PI by alkaline ISP method gel had better water-binding capacity than PI by acid ISP method gel. Both PI by alkaline ISP method and control gels showed a uniform and dense microstructure, while the microstructure of PI by acid ISP method gel was coarse and non-uniform. In conclusion, HIU-aided ISP under alkaline condition is effective to extract myofibrillar protein from chicken ribs while maintaining its gelation capacity, which is significant for value-added utilization of chicken ribs.
Nutrition & Hygiene
Effects of Antarctic Krill Oil, Fish Oil and Arachidonic Acid-Enriched Oil on Lipid Metabolism in Osteoporotic Mice
BAI Xiaolin, BO Yuying, DING Ning, WANG Qinghui, HAN Lihua, WANG Jingfeng
2022, 43(17):  131-137.  doi:10.7506/spkx1002-6630-20210606-073
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Objective: To compare the effects of Antarctic krill oil, fish oil and arachidonic acid-enriched oil on lipid metabolism in ovariectomized mice with osteoporosis. Methods: Eight-week-old healthy female C57BL/6J mice were subjected to bilateral ovariectomy to establish a model of postmenopausal osteoporosis. Other mice were subjected to a sham operation without ovariectomy and gavaged with normal saline. After successful establishment of the model, the mice were randomly divided into a model control group (normal saline), an Antarctic krill oil group (150 mg/kg mb), a fish oil group (80 mg/kg mb) and an arachidonic acid-enriched oil group (140 mg/ kg mb). After administration for 12 continuous weeks, bone mineral density, total cholesterol (TC) and triglyceride (TG) levels in the serum and liver, and the expression levels of lipid synthesis-related genes in the liver were determined. Results: Antarctic krill oil and fish oil, both rich in n-3 polyunsaturated fatty acids (PUFA), significantly reduced the body fat percentage of osteoporotic mice (P < 0.01), improved blood and liver lipid levels, and significantly down-regulated the mRNA expression of the genes encoding sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and stearoyl-CoA desaturase1 (SCD1) (P < 0.05, P < 0.01), while arachidonic acid-enriched oil increased blood lipid levels and up-regulated the expression of key lipid synthesis genes in the liver. Conclusion: Antarctic krill oil and fish oil can significantly alleviate lipid metabolism disorders in osteoporotic mice, with the former being more effective, while arachidonic acid-enriched oil has an opposite effect.
Protective Mechanism of Polysaccharide from Hosta ventricosa against Oxidative Damage in Cells
WU Jinshan, HUANG Rong, LIU Shuying, LIU Huimin, LIU Hongzhang, LIU Jingsheng
2022, 43(17):  138-146.  doi:10.7506/spkx1002-6630-20210602-026
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In this study, the extraction process of Hosta ventricosa root polysaccharide (HVRP) was optimized by response surface methodology (RSM), and the protective effect of HVRP on oxidative injury induced by tert-butyl hydroperoxide (t-BHP) in HepG2 cells was explored. Under the optimized conditions: extraction temperature 84 ℃, extraction time 3 h and solid-to-liquid ratio 1:31, the average extraction yield of HVRP was 23.9%, The mass fractions of reducing sugar, protein and uronic acid in HVRP were 11.17%, 0.6% and 12.31%, and HVRP showed absorption peaks characteristic of polysaccharides but no triple-helical conformation. HVRP had strong in vitro antioxidant activity and could significantly reduce the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) and increase the activity of catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH) and glutathione peroxidase (GPx) (P < 0.05, P < 0.01). The results of real-time quantitative polymerase chain reaction (qPCR) and Western blot analysis showed that HVRP could promotes the expression of antioxidant enzymes and consequently protect HepG2 cells from t-BHP-induced oxidation damage by regulating the Kelch-like epichlorohydrin-associated protein 1/nuclear factor erythroid 2-related factor 2/antioxidant response element (Keap1/Nrf2/ARE) signaling pathway. This study provides a theoretical basis for clarifying the antioxidant mechanism of HVRP and its application in functional foods.
Protective Effect of Oyster Protein Hydrolysate on Chronic Alcoholic Liver Injury in Mice
CAI Wenwen, GE Xiaodong, LI Na, GONG Shiyu, LIU Bin, CHEN Fuquan, ZENG Feng
2022, 43(17):  147-155.  doi:10.7506/spkx1002-6630-20210720-228
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This study aimed to explore the hepatoprotective effect of an enzymatic hydrolysate from oyster meat on chronic alcoholic liver injury in mice. After intervention with the hydrolysate, the serum levels of alaninetransaminase (ALT) activity, aspartate aminotransferase (AST) activity and total bile acid (TBA) concentration, liver index, and the contents of triglyceride (TG) and malondialdehyde (MDA) in the liver of mice with chronic alcoholic liver injury were measured, liver histomorphological changes were examined, and the mRNA transcription level of related genes in the liver and the changes of the gut microflora structure were analyzed. The results demonstrated that compared with the model group, the enzymatic hydrolysate at high and low doses significantly decreased the activity of serum ALT and AST and liver TG and MDA contents (P < 0.05, P < 0.01), but increased liver glutathione (GSH) content (P < 0.01). TBA content was significantly lower in the high-dose hydrolysate group (P < 0.05). The hydrolysate at high and low doses alleviated alcohol-induced liver damage in mice, and significantly down-regulated the mRNA transcription levels of the genes encoding toll-like recepror 4 (TLR4), tumor necrosis factor α (TNF-α), and nuclear factor-kappa B (NF-κB) (P < 0.05). The hydrolysate increased the abundance of Firmicutes as well as Lactobacillus and Alistipes, and reduced the abundance of Bacteroidetes in the gut of mice. In conclusion, the enzymatic hydrolysate can protect against chronic alcoholic liver injury in mice through reducing the activity of AST and ALT, and the contents of TG, MDA and TBA, increasing GSH content, down-regulating the mRNA transcription levels of TLR4, NF-κB and TNF-α, and changing the structure of the gut microflora.
Large-Leaf Yellow Tea Aqueous Extract Ameliorates Fatty Acid Metabolism in the Adipose Tissue of Obese Mice
LU Fengjuan, XU Na, SHEN Yuzhu, DONG Rongrong, WANG Min, ZHOU Dejie, CHU Jun
2022, 43(17):  156-163.  doi:10.7506/spkx1002-6630-20210510-094
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Objective: To explore the regulatory mechanism of large-leaf yellow tea aqueous extract on fatty acid metabolism in the adipose tissue of high-fat diet fed mice. Methods: Five-week-old male C57BL/6 mice were randomly divided into four groups: control (fed on a low-fat diet (LFD)), high-fat diet (HFD), high-fat diet + 2.5% large-leaf yellow tea aqueous extract (HFD + 2.5% YT), and high-fat diet + 0.5% large-leaf yellow tea aqueous extract (HFD + 0.5% YT). The body mass, adipose tissue mass and morphology, and the expression of key genes and proteins associated with fatty acid metabolism in each group of mice were measured after dietary intervention for 12 weeks. Results: Large-leaf yellow tea aqueous extract at a concentration of 2.5% significantly reduced the body mass and adipose tissue mass of HFD fed mice (P < 0.001), reduced lipid accumulation and promoted the expression of fatty acid synthesis genes such as SREBP-1C, FAS, ACC, SCD-1, and the the expression of fatty acid degradation genes such as PGC-1α and CPT-1. Moreover, large-leaf yellow tea aqueous extract activated the adenosine monophosphate activated protein kinase/acetyl CoA-carboxylase (AMPK/ACC) signaling pathway. Conclusion: Intervention with 2.5% large-leaf yellow tea aqueous extract prevents obesity and lipid deposition induced by high-fat diet, and promotes fatty acid synthesis and oxidative catabolism in adipose tissue through activating the AMPK/ACC signaling pathway.
Alleviating Effect of Bifidobacterium animalis subsp. lactis XLTG11 on Ulcerative Colitis Induced by Sodium Dextran Sulfate in Mice
MA Yan, WANG Zhongjiang, YANG Jingyu, LI Zhe, PENG Xia, CHEN Yufeng, LI Bailiang
2022, 43(17):  164-173.  doi:10.7506/spkx1002-6630-20210829-373
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Objective: To investigate the relieving effect of Bifidobacterium animalis subsp. lactis XLTG11 on ulcerative colitis induced by dextran sulfate sodium (DSS) in mice. Methods: Forty-five eight-week-old C57BL/6N male mice were randomly divided into three groups: normal, model and bifidobacterium treatment. To induce ulcerative colitis, the mice were allowed free access to 3% DSS in water. B. animalis subsp. lactis XLTG11 was gavaged to the animals at a dose of 1 × 107 CFU/d. The percentage change of body mass, colon length, disease activity index (DAI) and intestinal myeloperoxidase (MPO) activity were measured. Hstopathological changes were observed in the colon. Tumor necrosis factor (TNF)-α, interleukin 6 (IL-6), IL-1β, and IL-10 contents in the colon tissue were determined. The gut microbiota composition and the contents of fecal short-chain fatty acids were evaluated. The relative expression levels of genes related to intestinal barrier and the nuclear transcription factor (NF)-κB signaling pathway were detected. Results: Compared to the model group, B. animalis subsp. lactis XLTG11 significantly increased the percentage change of body mass (P < 0.05) and colon length (P < 0.01), and decreased DAI, MPO activity and proinflammatory cytokine levels (P < 0.01) in mice with DSS-induced ulcerative colitis. Moreover, it decreased the relative abundance of pathogenic bacteria, increased the relative abundance of short-chain fat acid-producing bacteria in the gut, significantly increased the contents of short-chain fat acids and the expression of genes related to intestinal barrier function (P < 0.01), and inhibited the activation of the NF-κB signaling pathway. Conclusion: B. animalis subsp. lactis XLTG11 could increase the percentage change of body mass and colon length, decrease DAI, MPO activity, and proinflammatory cytokine levels, regulate the gut microbiota composition, increase fecal short-chain fatty acid contents and the expression of intestinal barrier-related genes and inhibit the NF-κB signaling pathway, thereby effectively relieving DSS-induced ulcerative colitis in mice.
Effects of Ultrafine Ground Pea Dietary Fiber on Intestinal Flora and Metabolites in Diabetic Mice
LI Jiayi, WANG Honglei, YANG Qianqian, YANG Jinjie, JI Wei, NAN Xijun, SHENG Guihua
2022, 43(17):  174-181.  doi:10.7506/spkx1002-6630-20210508-071
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The aim of this study is to clarify the effects of ultrafine ground pea dietary fiber (UGPDF) on the intestinal microflora and metabolites of diabetic mice so as to reveal the mechanism of its hypoglycemic effect. A diabetic mouse model was established by intritoneal injection of streptozotocin, and the diabetic mice were gavaged with either metformin or UGPDF with high-dose (0.9 g/ (mL·d)) and low-dose (0.45 g/ (mL·d)) for four weeks. The changes in blood glucose level and liver cell morphology were measured during the experimental period. The protein expression levels of phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT) and insulin-like growth factors (IGF) were detected by Western blot. The composition of the fecal microbial flora of mice in each group was analyzed by high-throughput sequencing. The results showed that UGPDF could regulate the abundance and diversity of the intestinal microflora in diabetic mice. The number of operational taxonomic units (OTUs) in the high-dose UGPDF group was 300 ± 36, and the Shannon and Simpson indexes of this group were significantly different from those of diabetic mice. UGPDF intervention increased the abundance of beneficial bacteria such as Lactobacillus and Lachnospiraceae (P < 0.05), and decreased the abundance of pathogenic bacteria such as Helicobater, Klebsiella compared to the model group (P < 0.05). Moreover, after UGPDF intervention, the contents of six short-chain fatty acids in the feces of mice were significantly increased, and the most significant effect was observed in the high-dose group, showing an increase in the contents of acetic acid, propionic acid and butyric acid by 63.7%, 75.9% and 96.0%, respectively, reaching a level similar to that of the normal group. At the same time, the results of liver Histological examination and Western blot showed that UGPDF could regulate the PI3K/AKT/IGF signaling pathway in the liver of diabetic mice, repair liver cell injury and improve insulin sensitivity.
Angiogenic Promoting Activity of Different Phospholipids in Zebrafish
XIE Dongxiao, LI Haonan, MENG Ronghua, LI Peihai, ZHANG Mengqi, ZHAI Hongbin, LIU Kechun, MA Yaohong, LI Xiaobin
2022, 43(17):  182-187.  doi:10.7506/spkx1002-6630-20210422-325
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Purpose: The pro-angiogenic effects of different sources and types of phospholipids in zebrafish were evaluated and compared. Methods: Zebrafish embryos at 24 and 72 h post fertilization (hpf) were used to evaluate the effects of phospholipid samples (prepared from soybean, egg yolk or white shrimp head) on the growth of intersegmental vessel (ISV) and subintestinal vein vessel (SIV). Six experimental groups were set up, including blank control, model (treated with 0.25 μg/mL PTK787), positive control and phospholipid treatment (at concentrations of 20, 40 and 80 μg/mL). After incubation for 24 h, the ISV and SIV growth of transgenic zebrafish in each experimental group was observed and recorded by fluorescence microscopy. Results: The three phospholipids prepared in this study and two commercially available phospholipid products (iodized lecithin tablets and polyene phosphatidylcholine capsules) showed obvious pro-angiogenic activity on zebrafish with damaged ISV. All three phospholipids and four commercially available phospholipid products (iodized lecithin tablets, polyene phosphatidylcholine capsules, soybean phospholipid soft capsules, and fish oil capsules) showed obvious pro-angiogenic activity on SIV. Among these drugs, phospholipids in the head of Penaeus vannaceus had the strongest pro-angiogenic activity. Five phospholipid standards showed different angiogenesis promoting effects. Phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS) and high concentration (80 μg/mL) of sphingomyelin (SM) showed obvious pro-angiogenesis on ISV. All phospholipid standards showed obvious pro-angiogenic effects on SIV. Conclusion: Different concentrations of phospholipid extracts, commercially available phospholipid products and phospholipid standards had pro-angiogenic activity on zebrafish.
Preventive Effect of Linoleic Acid and α-Linolenic Acid Mixtures on Acute Liver Injury in Mice
SHA Shuang, FENG Qixin, ZHANG Xinrui, WANG Yue, YIN He, LI Chongwei
2022, 43(17):  188-198.  doi:10.7506/spkx1002-6630-20210823-298
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This study aimed to investigate the effect of linoleic acid and α-linolenic acid mixtures on acute liver injury and the intestinal microflora diversity in mice. In total 80 specific pathogen free (SPF) Kunming mice were divided into eight groups: normal, CCl4-induced model, positive control, and linoleic acid/α-linolenic acid mixtures at ratios of 4:1, 2:1, 1:1, 1:2 and 1:4. Serum immune functions and intestinal microflora structure in each group of mice were determined. The results showed that linoleic acid and α-linolenic acid mixtures could significantly reduce the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (P < 0.05), decreased liver and spleen indices (P > 0.05), and decreased the content of malondialdehyde (MDA) as well as the expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in liver cells (P < 0.05) compared with CCl4-induced model . These changes were consistent with the results of liver histopathological observation. High throughput sequencing results showed that the diversity of intestinal microflora in the model group dropped significantly compared with normal group (P < 0.05), while the diversity and abundance of intestinal microflora significantly increased after intervention with the 2:1 mixture of linoleic acid/α-linolenic acid compared with the CCl4 model group (P < 0.05), and its structure also changed. Moreover, the most prominent hepatoprotective effect was observed with the 2:1 mixture of linoleic acid and α-linolenic acid, which was basically consistent with that of silybin as a positive control. These results not only confirm the hepatoprotective effect of linoleic acid/α-linolenic acid mixtures, but also provide a theoretical basis for the scientific intake of linoleic acid/α-linolenic acid mixtures and serve as a guide for future development and application of hepatoprotective agents.
Packaging & Storage
Effect of Structural Protein on Tenderness of Beef from Qinchuan Cattle during Postmortem Aging
MA Xuhua, YANG Bo, LI Yalei, LUO Ruiming, ZHANG Xingya, ZHANG Meng
2022, 43(17):  199-207.  doi:10.7506/spkx1002-6630-20210706-050
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In order to explore the effects of structural proteins on the quality changes of Longissimus dorsi muscle from Qinchuan cattle during storage, 4D-label free quantification (4D-LFQ) was used to analyze the proteomic changes of beef Longissimus dorsi muscle during different storage periods (0, 2, 4, 6 and 8 days). The changes in shear force, myofibrillar fragmentation index (MFI) and protein content were measured as well. The results showed that the shear force tended to increase and then decrease during the storage period of 8 days (P < 0.01), the increase being greater than the decrease. The MFI showed a significant upward trend with storage time (P < 0.01), increasing by up to 250.81% after 8 days of storage; however, the opposite trend was observed for the total soluble protein content (P < 0.05), decreasing by up to 34.60%. Structural proteins in muscle tissue were degraded with postmortem metabolic changes in muscle tissue, which possibly affected tenderness development and caused a significant decrease in the content of myofibrillar protein (P < 0.05). The content of myofibrillar protein decreased rapidly at first and then slowly, decreasing by 50.56% over the entire storage period. During the first four days, the abundance of four proteins (alpha-actin-1, myosin heavy chain 9, myosin regulatory light chain 2, and myosin regulatory light chain 12B) were changed by regulating the calcium ion-binding and cytoskeletal protein-binding pathways in the development of skeletal muscle tissue. During the 8 days of storage, the abundance of eight proteins (myosin regulatory light chain 2, myosin heavy chain 6, alpha-actin-1, actin, alpha cardiac muscle 1, myosin regulatory light chain 2, troponin I 1, troponin I 2, and myosin heavy chain 15) was changed by regulating the calcium ion-binding pathway in the development of muscle organ and striated muscle tissue. Moreover, the structural proteins were degraded as a result of the regulation of the physiological state of cells by myosin binding, calcium ion binding, cytoskeletal protein binding myofibrillar assembly, skeletal muscle tissue development, muscle organ development, and striated muscle tissue development, leading to an increase in the MFI, thus improving the tenderness.
Transcriptomics and Proteomics Analysis Provide Insight into Metabolisms of Sugars, Organic Acids and Phenols in Hot Air Treated Peaches during Cold Storage
ZHOU Dandan, LI Tingting, WU Cai’e, TU Kang
2022, 43(17):  208-220.  doi:10.7506/spkx1002-6630-20210802-011
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Peach fruit is sensitive to chilling injury during low temperature storage. In order to comprehensively study the regulatory effects of hot air (HA) treatment on the metabolic pathways in peach fruit during cold storage, the fruit subjected to HA treatment at 40 ℃ for 4 h, and then stored at (1 ± 1) ℃ for 35 days. Samples were taken after every seven days for the determination of soluble sugar, citric acid, malic acid, total phenols, total flavonoids and anthocyanins in peach fruit. Besides, peaches were selected for the analysis of transcriptomics and proteomics. Results showed that HA significantly inhibited the decreases in sucrose, citric acid, malic acid, total phenols and total flavonoids, and the increases in fructose and glucose. Furthermore, HA significantly promoted the synthesis of anthocyanins (P < 0.05). Transcriptomics and proteomics analysis showed that most deferentially expressed genes (DEGs) and proteins (DEPs) regulated by HA were mainly concentrated in carbohydrate metabolism and secondary metabolite metabolism. The metabolic changes of soluble sugars and organic acids were mainly related to the expression of invertase, sucrose synthase, sucrose phosphate synthase, malate dehydrogenase and citrate synthase. In addition, HA treatment promoted the production of phenols, flavonoids and anthocyanins by up-regulating the expression of phenylalanine ammonia lyase, 4-coumaric acid CoA ligase, chalcone synthase, dihydroflavonol 4-reductase, anthocyanin synthase and UDP flavonoid glucosyltransferase. In summary, HA treatment could effectively suppress the decreases in sugars, organic acids and phenolic substances, and promotes an increase in anthocyanins in peach fruit during cold storage.
Quality Variations and Shelf Life Predictive Modeling of Moon Cake
LIU Dongqing, CHEN Pu, ZANG Peng, XU Nan, CHEN Junli, LIU Wei, ZHAO Wei, XIANG Hong
2022, 43(17):  221-230.  doi:10.7506/spkx1002-6630-20210830-400
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Changes in the sensory, physicochemical, microbiological characteristics of space moon cake were monitored during storage at 4, 22, 37 or 47 ℃. The zero-order or first-order kinetic model combined with the Arrhenius equation was used to establish a shelf life prediction model based on the quality indicators of moon cake. We found that the sensory score, pH, hue angle h, brightness (L* value) of space moon cake showed a downward trend over time. The results of electronic tongue analysis showed that the response to sourness increased towards the end of the shelf life, and the electronic nose response to sulfides, nitrogen oxides, organic sulfur, methane, and ethanol increased. Acid value, peroxide value, carbonyl value, a* value, total viable count, total mold and yeast count showed an upward trend over time, but no coliform was detected during storage. Correlation analysis showed that the prediction model based on acid value had the highest accuracy, with an activation energy (Ea) of 44.76 kJ/mol and a pre-exponential factor (k0) of 2.91 × 106, and the relative error between the predicted and measured values was smaller than 10%. The fat oxidation of space moon cake under different storage temperatures and times is the main factor affecting its quality. Its quality changes can be predicted by using the Arrhenius equation. This research can provide a reference for the prediction of the shelf life of space foods.
Effects of 1-Methylcyclopropene and Modified Atmosphere Packaging on the Softening and Related Physiological Changes in ‘Huo’ Persimmon during Postharvest Controlled Freezing Point Storage
MA Qin, FENG Juan, TIAN Jianwen, LIU Jun, LI Dongdong, ZHANG Yuanyuan, LIU Dunhua, LI Jiangkuo
2022, 43(17):  231-239.  doi:10.7506/spkx1002-6630-20210716-190
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To address the problem of rapid postharvest softening of persimmon fruit, the effects of treatment with 1.0 μL/L 1-methylcyclopropene (1-MCP), modified atmosphere packaging (MA) and their combination on the softening and related physiological indicators of ‘Huo’ persimmon fruit with and without calyx lobes were investigated during postharvest controlled freezing point ((-0.5 ± 0.3)℃) storage. It turned out that both individual and combined treatments delayed persimmon softening. Calyx lobe retention combined with MA provided the best maintenance of high CO2 and low O2 concentration in the storage environment and effectively inhibited β-galactosidase (β-Gal) activity. Calyx lobe removal combined with 1-MCP treatment was the most effective in delaying the decrease in fruit hardness, inhibiting the activity of cellulase (CX) and polygalacturonase (PG), reducing respiration intensity and ethylene production rate, and decreasing the loss of total flavonoids. 1-MCP + MA slowed down the decrease in skin hardness and reduced the loss of VC and total phenols. Furthermore, removing the calyx lobes delayed the emergence of a second ethylene peak. Overall, 1-MCP treatment of persimmon fruit without calyx lobes can delay persimmon softening and preserve persimmon quality well during CF storage.
Quality and Processing Characteristics of a Mixed Freeze-Dried Powder of Blueberry and Blue Honeysuckle Berries during Storage
ZHANG Xing, BI Jinfeng, CHEN Qinqin, WU Xinye, LI Xuan, LÜ Ying
2022, 43(17):  240-247.  doi:10.7506/spkx1002-6630-20210621-254
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The changes in the glass transition temperature (Tg), color, antioxidant components and antioxidant properties of a mixed freeze-dried powder of blueberry and blue honeysuckle berries were studied during at different temperatures (4, 25 and 37 ℃) and relative humidities (Hr, 43%, 75% and 95%) for up to 12 weeks. The behavior characteristics of the powder during storage were measured and analyzed as well. The results showed that compared with the other storage conditions, the basic physicochemical properties were better after 12 weeks of storage at 25 ℃ and 43% Hr (the Tg decreased by 4.62 ℃) or 4 ℃ and 75% Hr (the moisture content increased by 4.2%). In terms of the effect of antioxidant substance content and antioxidant capacity, with the prolongation of storage time, the contents of total phenols and total flavonoids and antioxidant capacity of different treatment groups decreased. The individual and total contents of six anthocyanins were least reduced at 25 ℃ and 43% Hr (the total anthocyanin content decreased by 23.92%), and the retention rate of total anthocyanins was higher at 4 ℃ and 75% Hr. The fluidity of the powder was maintained well after 12 weeks of storage at 25 ℃ and 43% Hr or 4 ℃ and 75% Hr. Therefore, both conditions were favorable for powder storage.
Chemical Pathway Analysis of Non-enzymatic Browning in Preserved Strawberry during Storage
NIU Liying, HU Lili, LI Dajing, LIU Chunju, ZHANG Zhongyuan, LIU Chunquan, CAO Binbin, GU Qianhui, XIE Tingting, WANG Yunhai
2022, 43(17):  248-254.  doi:10.7506/spkx1002-6630-20210818-241
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In order to illustrate the chemical pathway of the browning of preserved strawberry during storage, commercial preserved strawberries were stored at 37, 25 or 4 ℃ and evaluated for color parameters and the contents of ascorbic acid, total phenol, three free sugars, five free amino acids and 5-hydroxymethyl furfural (5-HMF), and correlation and cluster analyses were performed as well. The results showed that for each temperature, the color parameters L*, a*, and b* of preserved strawberry all decreased with storage time, and the total color difference ΔE was 11.42–33.33 after 90 days of storage, suggesting that the color of preserved strawberry changed obviously during storage. Additionally, the contents of ascorbic acid, total phenol, free sugars, and free amino acids decreased in varying degrees, while 5-HMF content increased linearly. The correlation analysis showed that ΔE was significantly correlated with all color and chemical parameters except glutamine content (P < 0.05, P < 0.01, P < 0.001), indicating that the browning may result from a combination of ascorbic acid degradation, polyphenol oxidation and Maillard reaction. Using cluster analysis, the samples stored at higher temperature and for a longer period of time were distinguished from others, suggesting that the influence of storage temperature and period on the browning degree cannot be neglected. In conclusion, during storage, ascorbic acid, total phenol, free sugars and free amino acids are involved in the browning of preserved strawberry, despite the asynchrony. The results of this study provide a rationale for browning control of preserved strawberry.
Effect of Short-Term Oxygen-Free Modified Atmospheres Containing Different CO2 Levels on Postharvest Physiology and Quality of Agaricus bisporus
WANG Jiali, TANG Jianxin, YING Limei, ZHANG Yunhe, SUN Bingxin
2022, 43(17):  255-262.  doi:10.7506/spkx1002-6630-20210802-013
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Agaricus bisporus tastes good and is nutritious, but its respiratory metabolism is strong and consequently its shelf life is short. In order to solve the problem of its poor storability, Agaricus bisporus was stored for a short period of time under oxygen-free modified atmospheres containing different levels of CO2 (5%, 10% and 20%) or a pure nitrogen atmosphere as a control and evaluated for postharvest quality indicators (mass loss, lightness, browning degree, texture, and taste value) and physiological indicators (respiration rate, relative conductivity, malondialdehyde (MDA) content, antioxidant contents). We found that a low-CO2 (5%) atmosphere was the most effective in preserving the quality of Agaricus bisporus, which could reduce the respiration rate and mass loss, inhibit browning, maintain firmness and springiness, delay the increase of cell membrane permeability, reduce oxidative damage and maintain the umami taste of Agaricus bisporus. But the preservation effect of a high-CO2 atmosphere was relatively poor, and the mushroom stored under a 20% CO2-containing atmosphere showed serious browning, increased cell membrane permeability and consequently serious electrolyte leakage, accompanied by oxidative damage.
Effect of Melatonin on the Senescence and Antioxidant Capacity of Capsella bursa-pastoris during Low-Temperature Storage
WANG Jieqiong, WANG Junping, ZHU Lijuan, YU Zhifang
2022, 43(17):  263-271.  doi:10.7506/spkx1002-6630-20210825-325
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Capsella bursa-pastoris (cv. Banye) was soaked in 100 μmol/L melatonin solution for 10 min and then stored at 2 ℃. Its quality and antioxidant capacity were evaluated as a function of storage time, and changes in chloroplast ultrastructure in its leaves were observed. The results showed that treatment with 100 μmol/L melatonin significantly reduced the respiration rate, inhibited the degradation of chlorophyll, decreased the accumulation of reactive oxygen species (ROS), and increased the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) and the contents of antioxidants. After 18 days of storage, melatonin-treated Capsella bursa-pastoris showed a 17.3% reduction in respiration rate, a 1.18- and 2.23-fold increase in the contents of ascorbic acid (ASA) and reduced glutathione (GSH), respectively, and a significant increase in the activities of SOD and glutathione reductase (GR) compared with the distilled water-treated control. The ultrastructural observation showed that the shape of chloroplasts and the lamellar structure of chloroplast grana in Capsella bursa-pastoris leaves were maintained well after treatment with melatonin. Therefore, melatonin treatment is beneficial to inhibit the yellowing, maintain the quality of Capsella bursa-pastoris and the structure of chloroplasts, and improve the antioxidant capacity of Capsella bursa-pastoris.
Preparation and Characterization of Tea Polyphenols @ Zeolitic Imidazolate Framework-8/Chitosan/Sodium Alginate Active Packaging Film
CAI Yue, WANG Mengjun, NIAN Linyu, CHENG Shujie, CAO Chongjiang, HUANG Zhigang
2022, 43(17):  272-281.  doi:10.7506/spkx1002-6630-20220217-123
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Using sodium alginate (SA) and chitosan (CS) as film-forming substrates and different concentrations (0%, 1%, 2.5% and 5%) of tea polyphenol (TP) @ zeolitic imidazolate framework-8 (ZIF-8) nanocomposites as a functional component, TP@ZIF-8/CS/SA composite membranes were prepared by layer-by-layer self-assembly. The morphology and composition of the composite films were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, texture analyzer and color different meter. The results showed that addition of TP@ZIF-8 nanomaterial at 5% changed the color, affected the microstructure, and enhanced the thermal stability, barrier performance, and mechanical properties of the composite films. In addition, addition of TP@ZIF-8 nano-composite imparted good antioxidant and antibacterial activity the composite films. Thus, the biodegradable composite active packaging films have good prospects for application in the field of food preservation.
Effects of Different Harvesting Methods on the Quality of Oudemansiella raphanipes under Simulated Cold-Chain Temperature Condition
WANG Zicheng, WANG Yafei, XIA Rongrong, MA Shiyu, YANG Zhen, LIU Yue, XIN Guang
2022, 43(17):  282-289.  doi:10.7506/spkx1002-6630-20220314-158
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Oudemansiella raphanipes is a rare edible mushroom with high nutritional value, which is loved by more and more consumers. However, its fruiting body has high water content and no epidermal protection, so it is very easy to decay and deteriorate during storage at normal temperature. Low-temperature cold chain conditions and harvesting methods can affect the storage quality of Oudemansiella raphanipes. In this study, Oudemansiella raphanipes harvested by cutting or pulling under the condition of cold chain temperature (10 ℃) was evaluated for changes in its sensory, nutritional, physiological and flavor attributes during storage. The results demonstrated different harvesting methods had significant effects on the quality of Oudemansiella raphanipes. The texture, color and electronic tongue taste value of Oudemansiella raphanipes harvested by pulling were better than those of Oudemansiella raphanipes harvested by cutting, while the latter effectively inhibited ethylene release in the early stage and superior to the former in terms of equivalent umami concentration (EUC) and the contents of polyphenols, flavonoids, soluble proteins, soluble sugars (in the late stage), total flavor nucleotides, flavor amino acids, and volatile C8 compounds. In conclusion, under the condition of cold chain temperature, Oudemansiella raphanipes harvested by pulling has relatively better sensory quality, while Oudemansiella raphanipes harvested by cutting has better nutritional flavor, which is suitable for the production of instant food products. This study provides a theoretical basis for solving the problem of quality deterioration of Oudemansiella raphanipes during storage.
Quality Preservation of Fresh-Cut Amaranth (Amaranthus crispus) by Combined Use of Blue Light and Fennel Essential Oil
JIN Siyuan, XIE Jing
2022, 43(17):  290-296.  doi:10.7506/spkx1002-6630-20210711-112
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The effect and mechanism of light-emitting diodes (LED) blue light with different photosynthetic photon flux densities (10, 20 and 30 μmol/(m2·s)) combined with fennel essential oil (0.35 μL/mL) on the quality preservation of fresh-cut amaranth was studied. Four treatment groups: T1 (fennel essential oil alone), T2 (10 μmol/(m2·s) blue light + fennel essential oil), T3 (20 μmol/(m2·s) blue light + fennel essential oil) and T4 (30 μmol/(m2·s) blue light + fennel essential oil) were designed as well as a control group without any treatment. The total bacterial count, physicochemical properties, antioxidant enzyme activity and sensory properties of each group were evaluated. The results showed that combined treatment with blue light (30 μmol/(m2·s)) and fennel essential oil (0.35 μL/mL) could maintain the contents of chlorophyll, ascorbic acid and soluble solids in amaranth well. The bacteriostatic effects of the four treatments could be ranked as follows: T4 > T3 > T2 > T1. Superoxide dismutase (SOD) and peroxidase (POD) activity of fresh-cut amaranth treated by 460 nm blue light and fennel essential oil were significantly higher than those in amaranth treated with fennel essential oil alone. The combined treatment effectively inhibited the accumulation of malondialdehyde (MDA) and nitrite in fresh-cut amaranth, significantly increased the sensory score, and extended the shelf life up to 10 days. Therefore, the combined treatment with LED blue light and fennel essential oil is an effective way to delay the senescence and preserve the quality of fresh-cut amaranth.
Effects of Electron Beam Irradiation on the Quality of Different Varieties of Kiwifruit
HUANG Tianzi, LI Ruijuan, YANG Shuxia, ZHANG Lu, LIANG Jin, WANG Dan, BAI Junqing, LUO Anwei
2022, 43(17):  297-305.  doi:10.7506/spkx1002-6630-20210512-146
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In an attempt to clarify the effect of electron beam treatment on the storage quality of kiwifruit, four varieties of kiwifruit (‘Hayward’ ‘Xuxiang’ ‘Huayou’ ‘Yate’) were treated with high-energy electron beam at at doses of 0.4, 0.8 and 1.2 kGy, and stored at 0–1 ℃ and relative humidity of 90%–95%. Samples were taken every 15 days to determine the effect of electron beam treatment on fruit firmness, mass loss rate, soluble solids content, titratable acid content, vitamin C (VC) content during cold storage. The results showed that electron beam irradiation treatment had a positive effect on maintaining the storage quality of kiwifruit. The appropriate dose of electron beam irradiation inhibited the mass loss of kiwifruit during storage, delayed the decrease of titratable acid content, and increased the content of flavonoids. The content of polyphenols was increased at the early stage of storage. The irradiation treatment decreased fruit firmness and VC content but increased the content of soluble solids. Electron beam irradiation at 0.8 kGy was more effective in delaying the increase of soluble solids content and the decrease of titratable acid content, and increasing the contents of polyphenols and flavonoids. Overall, among the tested varieties, ‘Hayward’ and ‘Yate’ kiwifruits were more tolerant to electron beam irradiation, and the doses of 0.4 and 0.8 kGy provided better quality preservation of ‘Hayward’ and ‘Yate’ kiwifruit during postharvest storage. Therefore, the appropriate dose of electron beam irradiation can be used as an effective means to improve the quality preservation of kiwifruit.
Reviews
Application of Aggregation-Induced Emission Materials in the Identification and Detection of Food-Borne Pathogens: A Review
DOU Leina, WANG Zhanhui, YU Wenbo, SHEN Jianzhong
2022, 43(17):  306-315.  doi:10.7506/spkx1002-6630-20210812-161
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Food-borne pathogens are one of the major factors causing food safety incidents. Therefore, designing new probes for the rapid identification and detection of food-borne pathogens is of great significance to ensure food safety and human health. Aggregation-induced emission (AIE) materials are a new type of fluorescent material that has been discovered in recent years. AIE materials have the characteristics of ‘the more aggregated, the more luminescent’, endowing them with the advantages of low background, high signal intensity, and strong light stability. Besides, AIE probes can be used without the need for any washing procedure, greatly saving the operation time and reducing sample loss. AIE probes have been of interest to researchers due to their potential in the identification and detection food-borne pathogens. This paper comprehensively analyzes and summarizes the application of AIE materials in the identification and detection food-borne pathogens, with a focus on the relationship between the molecular structures of AIE materials and their functions of AIE materials in the typing, species identification, and viability determination of food-borne pathogens. This paper also discusses the present shortcomings and possible future directions in this field.
Recent Advances in Collagenase from Clostridium histolyticum
XIAO Han, LIU Xiufang, ZHENG Lin, ZHAO Mouming, HUANG Mingtao
2022, 43(17):  316-325.  doi:10.7506/spkx1002-6630-20210830-385
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Collagen, one of the most abundant proteins in mammals, is hardly degraded by conventional proteases due to its special triple-helix structure. Collagenase is able to cleave collagen under physiological conditions, which has been widely applied in the medicinal and food industries. A lot of research has been done on collagenase from Clostridium histolyticum. In this review, we summarize the structural characteristics, the collagenolytic mechanism, the current status of production, and the application of collagenase (Col) G and ColH from Clostridium histolyticum in order to provide a rationale for further development and utilization of collagenase.
A Review on the Effects of Dietary Protein and Carbohydrates on Sleep
LAI Meiling, LI Anqi, WANG Qiaoping
2022, 43(17):  326-331.  doi:10.7506/spkx1002-6630-20210616-190
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A great deal of research has demonstrated that the macronutrients protein and carbohydrate in foods have a major influence on sleep. However, results from different studies are inconsistent, so it remains unclear how protien and carbohydrate affect sleep. This review has summarized the recent studies on the effects of protien and carbohydrate on sleep, revealing that high-carbohydrate low-protein foods may be helpful to promote sleep and improve sleep quality. This review may provide a theoretical guidance for improving sleep based on dietary nutrients.
Analysis of Research Hotspots on Taste Receptors
ZHANG Yichun, CHEN Yanhong, LI Lijun, NI Hui
2022, 43(17):  332-343.  doi:10.7506/spkx1002-6630-20210601-011
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Taste is an important perceptual response, and the basic tastes include sweet, sour, bitter, salty, and umami. Taste receptors are proteins that perceive various tastes. In this paper, the topical keywords on taste receptors, the sources and types of taste receptors that have been researched, the methods used for taste receptor research, and the researchers engaged in the study of taste receptors are analyzed and summarized to provide a reference for taste receptor research. Through literature analysis, it is found that bitter taste, sweet taste, sour taste, umami taste, rat, human, mouse, cell, expression, protein, induction, gene, signal, neuron and molecule are the topical keywords on research of taste receptors. The Proceedings of the National Academy of Sciences, the Journal of Neuroscience, the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology and the Journal of Comparative Neurology are the key journals in the field of taste receptors. Murine taste receptors are the object of most research in this field, but there are still large differences between murine and human taste receptors. Therefore, further research is needed to accurately understand human taste receptors. At present, taste receptors have researched at the structural biological and neurobiological levels by means of computer simulation and molecular biology experiments. The structures of the medaka fish T1R2/T1R3 ligand recognition domain, zebrafish Otop1 and chicken Otop3 and the signaling pathways of each taste receptor have been elucidated. However, the accurate structures of most receptors have not been fully understood, and it is difficult to distinguish taste nerve stimuli with different characteristics. Currently, obtaining single crystals of G protein coupled receptors (GPCRs) by protein expression, protein structure elucidation and signal transduction, and elucidating the crystal structure and the interaction mechanism between various receptors are major research directions. The United States is a leader in the field of taste receptors, and its scientists such as Ryba N. J. P., Hoon M. A., and Chandrashekar J. have led the research direction in this field. This review clarifies the current status of the field of taste receptors and predicts future trends in this field, which will hopefully provide new directions and ideas for researchers.
Recent Advances in Biosensors Based on Surface Enhanced Raman Scattering Labels for the Detection of Pesticide Residues
YAN Mengmeng, LI Huidong, ZHANG Wenjun, CHEN Zilei, GUO Changying, ZHU Chao, SHE Yongxin
2022, 43(17):  344-352.  doi:10.7506/spkx1002-6630-20210908-092
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Recently, surface enhanced Raman scattering (SERS) labels have attracted researchers’ attention owing to their high sensitivity, excellent multiplexing ability, insensitivity to photobleaching and good fidelity of molecular fingerprint, and have been successfully applied to sensing analysis and biological imaging. In this review, we summarize the principle of SERS label-based biosensors, and the state of the art in their application for rapid detection of pesticide residues. The focus of this review is on the design and fabrication of SERS labels and the current status of sensing systems based on different recognition elements. Meanwhile, the challenges in this field are discussed and possible solutions to them are proposed. This review is expect to help expand the application of SERS labels in the detection of pesticide residues and food safety.
Review on Recent Progress in the Mechanism and Application of Interaction between Prolamins and Polyphenols
CHEN Xiaoling, GUAN Weiliang, SHI Peiying, ZHENG Ping’an, HOU Dongyuan, SUN Zhidong, ZHANG Jinjie, CAI Luyun
2022, 43(17):  353-361.  doi:10.7506/spkx1002-6630-20210506-037
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Prolamins and polyphenols are two important components that usually coexist in foods. Both components play important roles in the sensory and functional properties and quality of food products. The interaction of prolamins and polyphenols is ubiquitous in the food system, which can influence their structures, functional properties and bioavailability. Firstly, this review describes the formation mechanism of protein-polyphenol complexes and the factors affecting the interactions between them including non-covalent and covalent interactions, which are closely related to the chemical structures of the two compounds and the external environmental conditions. Secondly, the effect of the interactions between prolamins and polyphenols on the functional properties of their complex including emulsifying properties, antioxidant activity, and thermal stability is discussed. Finally, the recent applications of prolamin-polyphenol complex in emulsions, films and delivery systems are reviewed, aiming at providing a theoretical basis for the high-value utilization of prolamins and polyphenols, the development of products based on them, and their applications in food and related fields.
Recent Advances in Detection Technologies for Dietary Advanced Glycation End Products
LI Huatao, ZHANG Qiaozhi, NI Haojie, WANG Yanbo, LIU Fuqi, FU Linglin
2022, 43(17):  362-371.  doi:10.7506/spkx1002-6630-20220304-056
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Advanced glycation end products (AGEs) are a class of heterogeneous compounds formed by the Maillard reaction between reducing sugars and free amino groups of proteins. Studies have found that dietary AGEs can be accumulated in the body, causing hazardous effects on human health. Therefore it is necessary to carry out detection and analysis of typical AGEs in foods. Currently, due to the wide variety and complex structure of dietary AGEs, there is a lack of general analytical methods for their detection. Therefore, this paper presents a review of the structure and types of dietary AGEs, their relationship with human health, and their state-of-the-art detection technologies. A specific focus is put on the immunoassays and instrumental methods used for the detection of dietary AGEs as well as their characteristics, advantages, and disadvantages. Furthermore, this paper provides an outlook on the future research directions in this field. We expect that this review will provide references for the development of new methods for the detection of dietary AGEs and the establishment of related research systems.
Recent Progress in Research on the Role of Lactoferrin in Regulating the Development and Metabolism of Adipocytes
AN Qin, WANG Xiong, WANG Wenli, CHENG Zhimei, DAI Yunping, ZHANG Yali
2022, 43(17):  372-379.  doi:10.7506/spkx1002-6630-20210422-323
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Obesity is one of the most serious public health problems, and the development and metabolism of adipocytes are closely related to obesity. As a multifunctional glycoprotein, lactoferrin has a variety of physiological activities and can regulate the development and metabolism of adipocytes by regulating their proliferation and differentiation, the expression levels of lipid metabolism-related genes, and the expressions of adipocytes and inflammatory factors. This article reviews recent progress in research on the role of lactoferrin in regulating the physiology of adipocytes and the underlying mechanism, and proposes future research directions and focuses on the role of lactoferrin in regulating the development and metabolism of adipocytes. It is anticipated that this paper will provide a basis for further research on the functions of lactoferrin and its industrial applications.
Progress in the Application of New Tumbling Technologies in Meat Processing
YU Qiuying, ZHAO Honglei, CHANG Jingyao, KONG Baohua, LIU Qian
2022, 43(17):  380-388.  doi:10.7506/spkx1002-6630-20210804-052
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Tumbling technology is widely used in the processing of meat products, which plays an important role in tenderizing raw meat, improving curing efficiency, reducing cooking losses, and improving product quality. However, the application of conventional tumbling technology is affected by many factors (such as temperature, time, speed, method, and vacuum degree), thereby affecting product quality. With the emergence of new food processing technologies, their combination with traditional tumbling technology can improve the application efficiency of tumbling in meat processing. Based on previous studies, this article systematically reviews the integration of new food processing technologies and traditional tumbling technology, as well as the application of new tumbling technologies in meat processing, which will hopefully provide theoretical and technical guidance for the application and development of new tumbling technologies.
Progress in Research on the Structural Characteristics of Tea Polysaccharides
CHEN Li, LU Anxia, LIU Fei, YE Yulong
2022, 43(17):  389-397.  doi:10.7506/spkx1002-6630-20210412-171
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Tea polysaccharides are a class of compound polysaccharides with very complex structures. This article reviews the factors that influence the polysaccharide content in tea, the analytical methods to determine the structure of tea polysaccharides and their characteristics. The content of polysaccharides in tea varies depending on various factors such as tea plant varieties, maturity, tea plant organs, tea processing methods and the tea plant growth environment. The structural unit of tea polysaccharides consists of eight neutral monosaccharides, two alduronic acids, 1.87%–38.00% protein, 18 amino acids and a small amount of inorganic elements. Their molecular masses are in the range of 2.56–3 900.00 kDa. Their sugar chains are composed of monosaccharides linked through the oxygen atoms by glycosidic bonds such as (1→2), (1→3), (1→4), (1→2,4), and contain branches. Some tea polysaccharide molecules have a triple helix structure, which can intertwine and bind together to form aggregates of various shapes and sizes. The structure of tea polysaccharides is usually analyzed by chromatography, spectroscopy, nuclear magnetic resonance, atomic force microscopy, and scanning electron microscopy. In addition, this article also briefly summarizes the structure-activity relationship of tea polysaccharides, in order to provide a basis for further research on the structure characteristics and biological activities of tea polysaccharides.
Fresh Daylily: Progress in Research on Its Senescence Mechanism and Review of Technologies for Its Postharvest Preservation
LI Kexin, ZHANG Chaofan, LIU Peiye, ZHAO Yumei, CAO Jiankang
2022, 43(17):  398-404.  doi:10.7506/spkx1002-6630-20210520-244
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Fresh daylily is a traditional characteristic vegetable in China, which has high nutritional and economic value, but it is extremely susceptible to a series of deterioration phenomena. This paper reviews recent studies on the biological changes associated with postharvest senescence in fresh daylily, the underlying physiological and biochemical metabolic mechanisms, the factors affecting postharvest senescence in fresh daylily, and postharvest preservation techniques. We believe that this review will provide a novel idea for understanding the senescence mechanism of fresh daylily and improving its postharvest preservation.