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Basic Research
Relationship between Glycolysis and Water-Holding Capacity of Tan Sheep Meat during Maturation
WANG Jinxia, LIU Jijuan, LUO Ruiming, LI Rong, CHEN Xueyan, ZHANG Qian, HU Lijun
2024, 45(6):  1-7.  doi:10.7506/spkx1002-6630-20230208-071
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In order to clarify the relationship between the degree of glycolysis and water-holding capacity during the maturation of Tan sheep meat, the M. longissimus dorsi of six-month-old Tan sheep was aged at 4 ℃ postmortem and evaluated for drip loss, purge loss, calpain-1 activity, myofibril fragmentation index (MFI), ATP content, glucose content, glycogen content, lactic acid content, lactate dehydrogenase (LDH) activity, pyruvate kinase (PK) activity and pH after 0, 1, 2, 3, 4 and 8 days. The results showed that as maturation time increased, drip loss, purge loss and centrifugal loss increased first and then decreased (P < 0.05), reaching their maximum values on day 4. ATP and glycogen contents continued to decrease (P < 0.05). The contents of glucose and lactic acid increased first and then decreased (P < 0.05), and so did LDH activity (P < 0.05), reaching its maximum level on day 4. PK activity showed a constant decreasing trend (P < 0.05). The correlation analysis showed that glycogen content was negatively correlated with drip loss (P < 0.05) as well as purge loss and centrifugal loss (P < 0.01), and positively correlated with nuclear magnetic resonance (NMR) transverse relaxation times (T21, T22 and T23) (P < 0.05 or P < 0.01). LA content was significantly positively correlated with drip loss (P < 0.001) as well as purge loss and centrifugal loss (P < 0.01), but had no correlation with T21, T22 or T23. Therefore, the glycolysis process of Tan sheep meat was activated rapidly after slaughter, which caused change in the activity of glycolysis-related enzymes and the contents of metabolites, thereby resulting in changes in the water adsorption capacity of muscle proteins, and ultimately affecting the water-holding capacity of Tan sheep meat after slaughter.
Physicochemical Properties and Antioxidant Activity in Vitro of Selenium-Enriched Pea Seedling Powder
WANG Zhiwei, LI Qian, ZHANG Min
2024, 45(6):  8-14.  doi:10.7506/spkx1002-6630-20230123-164
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The physicochemical properties and antioxidant activity in vitro of selenium-enriched pea seedling powders produced by hot air drying or freeze drying were studied. The effects of different drying processes on the percentage loss of organic selenium content, color, microstructure, water distribution and antioxidant activity in vitro of pea seedling powder were investigated by chemical analysis and instrumental analyses using colorimeter, scanning electron microscopy (SEM) and low-field nuclear magnetic resonance (NMR). The results indicated that the product prepared by hot air drying at 100 ℃ had desired quality with a small percentage loss of organic selenium of 36.7% and good color. Selenium-enriched pea seedling powder consisted of blocky particles with more wrinkled surface and a larger number of fiber bundles compared with ordinary pea seedling powder. There were significant differences in water distribution between Se-enriched and non-Se-enriched pea seedling powder prepared by hot air drying. Compared with non-Se-enriched pea seedling powder, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging capacity (half maximal inhibitory concentration IC50 = 0.61 mg/mL), hydroxyl free radical scavenging capacity (IC50 = 0.86 mg/mL), superoxide anion radical scavenging capacity (IC50 = 0.90 mg/mL) and ferric reducing power (absorbance value = 0.30) of the ethanol extract from Se-enriched pea seedling powder were significantly higher (P < 0.01). These results provide theoretical guidance and a technical reference for the development of organic selenium supplements and the industrialization of selenium-enriched foods.
Food Chemistry
Effects of Five Oxidative Decontaminating Agents on the Quality and Proteins of Tilapia Fillets
YAN Yuhong, HUANG Hui, LI Laihao, HAO Shuxian, CHEN Shengjun, CEN Jianwei, WU Yanyan, WEI Ya , XIANG Huan
2024, 45(6):  15-23.  doi:10.7506/spkx1002-6630-20230525-245
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In this study, the effects of five common oxidative decontaminating agents (H2O2 solution, ClO2 solution, NaClO solution, ozonated water and slightly acidic electrolytic water) on the bacterial decontamination of tilapia fillets and their influence on the texture, color and myofibrillar protein (MP) oxidation in tilapia fillets were investigated. The results showed that a decontamination rate of 80% was attained by immersion in 1 500 mg/L H2O2 solution for 8 min, 200 mg/L ClO2 solution for 10 min, 200 mg/L NaClO solution for 10 min, 9 mg/L ozonated water for 10 min, or 30 mg/L slightly acidic electrolytic water for 20 min. Compared with the control group, treatment with decontaminating agents increased the hardness and L* value of tilapia fillets, decreased the a* value, MP content, total sulfhydryl group content, and raised the content of carbonyl groups and the amount of surface hydrophobic groups. The degree of protein denaturation in the slightly acidic electrolytic water and NaClO solution groups was the highest; the fluorescence intensity of MP was decreased after decontamination treatments, with the greatest decrease being found in the slightly acidic electrolytic water-treated group; the relative contents of α-helix and β-turn in MP were decreased, while the relative contents of β-fold and random coil were increased, with the most significant changes in the secondary structure of MP being observed in the slightly acidic electrolytic water-treated group (P < 0.05). MP underwent degradation to different extents, and the degradation degree of the slightly acidic electrolytic water group was higher than that of the other treatment groups. In summary, the oxidation of fish MP occurred to varying degrees after oxidative decontamination treatments, with slightly acidic electrolytic water treatment having the strongest oxidative effect.
Rheological Properties and in Vitro Digestion of Protein-Rich Thick Milk Incorporated with Hericium erinaceus Powder
SU Cuixin, WEI Shijie, CHANG Mingchang, FENG Cuiping, CAO Jinling, YUN Shaojun, XU Lijing, GENG Xueran, CHENG Fei’er, MENG Junlong, CHENG Yanfen
2024, 45(6):  24-31.  doi:10.7506/spkx1002-6630-20230505-033
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A high protein food that is easy to swallow for people with dysphagia was prepared by blending milk with Hericium erinaceus (HE) powder, soy protein isolate (SPI) or whey protein (WP) (which was added to obtain a final protein content more than 10% of the total mass), and one of three thickeners including xanthan gum (XG), kappa carrageenan (KC) and carboxymethylcellulose (CMC), and its rheology, viscoelastic properties and in vitro digestion characteristics were determined. The results showed that all samples exhibited a weak gel behavior. According to the steady-state rheological test, the values of high resistance to deformation (high G* value) and good elasticity (low tan δ value) were ranked as follows: HE-SPI-CMC > HE-SPI-XG > HE-WP-XG > HE-WP-KC, and higher G* values were more favorable for people with dysphagia and the elderly. In the in vitro simulated digestion test, the viscosity (η) and consistency coefficient (K) values were in the following order: HE-WP-KC > HE-WP-XG > HE-SPI-XG. The soluble protein contents were ranked as follows: HE-WP-CMC > HE-WP-KC > HE-SPI-KC. The contents of free amino acids after digestion were in the following order: HE-WP-CMC > HE-WP-KC > HE-SPI-KC > HE-WP-XG. Therefore, HE-WP-KC was more suitable for consumption by the elderly. This study has explained how protein-hydrocolloid interactions and food matrix determine the rheological properties and digestibility properties of the samples, which may provide theoretical support for meeting the dietary needs of people with dysphagia.
Preparation, Modification and Characterization of Nanoliposomes Loaded with Curcumin and Reduced Glutathione
YU Shaoxuan, PANG Geyu, ZHANG Zihao, LI Shiyang, XU Shuo, XIAO Haifang, ZHU Lanlan, SONG Yuanda
2024, 45(6):  32-40.  doi:10.7506/spkx1002-6630-20230519-187
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Nanoliposomes loaded with curcumin (CUR) and reduced glutathione (GSH) were prepared using soybean lecithin as the wall material and modified by chitosan and sodium alginate on their surface through electrostatic self-assembly. The encapsulation efficiency, morphology, in vitro release, and stability of the fabricated nanoliposomes were characterized by laser particle size analyzer, transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the encapsulation efficiency of CUR was 100%. Moreover, neither co-encapsulation with GSH nor polysaccharide modification affected the encapsulation efficiency of CUR. However, the encapsulation efficiency of GSH was increased from 7.90% to 27.03% when co-encapsulated with CUR, and further increased to 41.22% after polysaccharide modification. Co-encapsulation of CUR and GSH did not significantly influence the release of CUR, but reduced the release rate of GSH from 51.2% to 23.6%. After polysaccharide modification, the sustained release effects of nanoliposomes loaded with CUR and/or GSH were enhanced. Meanwhile, the co-encapsulation of CUR and GSH increased the average particle size of liposomes from (95.02 ± 1.93) to (132.47 ± 18.14) nm, and the zeta potential from (–22.47 ± 1.96) to (–14.70 ± 0.46) mV. After bilayer modification of chitosan and sodium alginate, the average particle size of liposomes further increased to (161.97 ± 5.58) nm, while the zeta potential decreased to (–40.87 ± 1.79) mV. In addition, the thermal stability was increased. The results of this study will provide a basis for the development of novel functional foods or drugs loaded with bioactive substances.
Effect of Amylose Content on Stability of Maize Starch-Tea Polyphenol Emulsion Gels
WANG Ran
2024, 45(6):  41-47.  doi:10.7506/spkx1002-6630-20230821-149
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Maize starch with different amylose contents and tea polyphenols (TP) were co-heated to prepare maize starch-TP hydrogels, and the hydrogels were used to stabilize food-grade emulsion gels. The effects of amylose contents on the microstructure, rheological behavior and emulsification properties of maize starch-TP hydrogels and emulsion gels stabilized by it. The results showed differences in the amount of retained TP among maize starch hydrogels with different amylose contents and consequently in the microstructure of maize starch-TP hydrogels. As the amylose content decreased, the size of droplets in emulsion gels stabilized by maize starch-TP hydrogels decreased, and the viscosity and viscoelasticity of emulsion gels increased, suggesting the formation of network structures in emulsion gels. As observed by cryo-scanning electron microscopy (cryo-SEM), a structurally compact network matrix was formed in emulsion gels with decreasing amylose contents. The hydrogel network matrices could adhere to oil droplets, thereby hindering their coalescence, and maintaining the stability of emulsion gels for a long time. This study can provide a theoretical foundation for developing starch-based emulsion gels and delivery vehicle for bioactive substances in the food industry.
Bioengineering
Effect of Basigin on the Mitogen Activated Protein Kinase Signaling Pathway and Apoptosis in Qinchuan Cattle Muscle during Postmortem Maturation
SU Xiaofeng, LI Yalei, LUO Ruiming
2024, 45(6):  48-54.  doi:10.7506/spkx1002-6630-20230519-194
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In order to explore the effects of basigin (BSG) on the mitogen activated protein kinase (MAPK) signaling pathway and apoptosis in Qinchuan cattle muscle during postmortem maturation, the changes in BSG and related differentially expressed proteins were analyzed by 4D-label free quantification (4D-LFQ). The BSG inhibitor tunicamycin was injected into the longissimus dorsi of Qinchuan cattle after slaughter, and the expression levels of key proteins in the MAPK signaling pathway during storage at 4 ℃ were determined by Western blotting. An apoptosis detection kit was used to determine the change in the activity of caspase-3. The results showed that the expression of BSG increased first and then decreased during the postmortem storage period of Qinchuan cattle muscle. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, it was found that BSG and related differentially expressed proteins were significantly annotated to the oxidative phosphorylation pathway, calcium signal pathway and MAPK signaling pathway, indicating that BSG played an important role through the MAPK signaling pathway. In addition, for the tunicamycin group, the relative expression of the key proteins in the MAPK signaling pathway was significantly down-regulated, indicating that BSG inactivated the MAPK signaling pathway. This finding lays a good foundation for exploring the effect of BSG on the MAPK signaling pathway. After inhibiting BSG expression, caspase-3 activity in the tunicamycin group increased significantly, indicating that apoptosis was an important link in cell injury mechanism, and tunicamycin acted on the N-terminal structure of BSG to deglycosylate the protein and inhibited the folding of intracellular proteins and consequently their biological activity, thereby inducing cell apoptosis.
Screening and Identification of Probiotics with in Vitro Anti-Allergic Activity Based on the Degranulation Inhibition of RBL-2H3 Cells
Ma Ding, Qin Shuangxia, Hao Huichao, Deng Fangming, Zhao Lingyan
2024, 45(6):  55-63.  doi:10.7506/spkx1002-6630-20230613-098
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To investigate the anti-allergic activity of lactic acid bacteria, lactic acid bacterial strains were obtained from fermented vegetables by the traditional isolation technique and screened for in vitro allergic activity by the degranulation inhibition assay against RBL-2H3 cells. The results showed that all four isolates exhibited good probiotic properties and safety and had a strong inhibitory effect on β-hexosaminidase released from RBL-2H3 cells after degranulation. Moreover, they showed significant down-regulation effects on the release of histamine, tumor necrosis factor-α and interleukin-4 from RBL-2H3 cell after degranulation, suggesting their potential as anti-allergic probiotics. The four strains were identified by 16S rDNA sequencing as two strains of Lactobacillus plantarum, one strain of L. fermentum and one strain of L. paracasei.
Screening of Fungal Strains for Single-Culture Solid-State Fermentation of Liupao Tea
WU Xinhui, DU Jinjie, LIU Xiaochun, LIAO Kaibin, QIN Yuna, LIANG Weijie, ZHANG Lingzhi, LONG Zhirong, QIU Ruijin
2024, 45(6):  64-71.  doi:10.7506/spkx1002-6630-20230608-075
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In this study, 20 fungal strains isolated from Liupao tea were used for solid-state fermentation of sterilized raw Liupao tea from Cangwu Quntizhong. The fermentation performance of these strains was explored by sensory evaluation and biochemical analysis combined with principal component analysis (PCA) and strains that are able to significantly improve the quality of Liupao tea or impart new flavor to the tea were selected. The results showed that nine fungi with excellent fermentation performance were obtained, namely, Aspergillus tubingensis, A. niger, Penicillius manginii, A. keratitidis, A. ruber, A. intermedius, P. commune, A. amstelodami and Trichomonascus ciferrii. Moreover, A. tubingensis, A. niger, P. commune and A. amstelodami could significantly change the contents of 18 chemical components in tea samples. P. commune and A. amstelodami were identified as excellent starter cultures for Liupao tea fermentation. This study could provide a theoretical basis for the improvement of the fermentation process of Liupao tea and the development, innovation and quality improvement of tea products.
Inhibitory Effect of Linalool against the Ginger Fusarium Wilt Pathogen
ZHOU Lirong, ZHANG Lingling, XIONG Shijie, MA Jiawei, ZHU Yongxing, SUN Chong, ZHU Xuedong, LIU Yiqing
2024, 45(6):  72-79.  doi:10.7506/spkx1002-6630-20230512-108
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To study the antifungal effect and mechanism of linalool against Fusarium oxysporum FOX-1, the causative agent of ginger Fusarium wilt, the damaging effects of different concentrations of linalool on the mycelial growth, spore germination and cell membrane of F. oxysporum FOX-1, and its control effect on ginger Fusarium wilt were systemically investigated. The results showed that linalool could significantly inhibit the mycelial growth of F. oxysporum FOX-1 in a concentration-dependent manner, and the half maximal effective concentration (EC50) and the minimum inhibitory concentration (MICs) were 1.183 and 2 g/L, respectively. The spore concentration of F. oxysporum FOX-1 treated with linalool at MIC for 6 h was (1.43 ± 0.12) × 104 spores/mL, which was significantly lower than that of the control group ((5.79 ± 0.19) × 104 spores/mL) (P < 0.05), and the spore germination rate of F. oxysporum FOX-1 treated with linalool at MIC for 12 h was (5.83 ± 2.16)%, which was significantly lower than that of the control group ((95.12 ± 3.78)%) (P < 0.05). Treatment with linalool at 1/2 MIC and MIC damaged the integrity of the cell membrane, resulting in a significant increase in relative electrical conductivity and nucleic acid leakage in the mycelial suspension and malondialdehyde (MDA) content in the mycelium, and a significant decrease in ergosterol content, finally weakening the pathogenicity of the fungus. No lesions appeared on ginger pieces after treatment with linalool at MIC for 3 days. In conclusion, linalool affects the normal physiological function of F. oxysporum FOX-1 by inhibiting its spore germination and mycelial growth and destroying its cellular structure. This study provides a new direction for the effective control of Fusarium wilt.
Antibacterial Activity and Mechanism of Rhamnolipids against Bacillus cereus
NIU Yongwu, QIAO Shan, SUN Yiming, WANG Yuchen, ZHAO Renyong, TIAN Shuangqi
2024, 45(6):  80-86.  doi:10.7506/spkx1002-6630-20230215-144
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The antibacterial activity and mechanism of rhamnolipids (RLs) against Bacillus cereus spores were analyzed from the aspects of appearance, morphology, and cell membrane state. The results showed that minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of RLs were 80.0 and 160.0 mg/L, respectively. Both concentrations of RLs caused severe shrinkage and depression on the surface of spores, and disrupted the integrity and permeability of the spore cell membrane, leading to the leakage of intracellular electrolytes, DNA and proteins. In addition, RLs inhibited and inactivated B. cereus spores by various mechanisms such as decreasing heat resistance, generating oxidative stress, reducing surface adhesion, and binding to and interfering with DNA molecules. The results of this study will contribute to the development and application of RLs in the field of food safety.
Microbial Community of Chilled Goose Breast and Its Effect on Volatile Flavor Components
WU Lizhen, LIAO Zhiqiang, SHI Yangkai, YU Limei
2024, 45(6):  87-96.  doi:10.7506/spkx1002-6630-20230606-046
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In order to establish an effective mechanism for predicting spoilage of chilled goose breast meat, the microfloral succession was investigated by high-throughput sequencing and the dominant spoilage bacteria of chilled goose breast meat were determined. Meanwhile, the effects of three dominant spoilage bacteria on the volatile flavor substances of chilled goose breast meat were characterized by using gas chromatography-ion mobility spectrometry (GC-IMS) and solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The results showed that the diversity of microflora was richer during the early and late storage periods. The dominant phylum was Amoeba, and the dominant spoilage bacterium was Pseudomona. Pseudomona began to grow significantly starting from day 3 and reached a peak with a relative abundance of 96.79% on day 9. Contamination with the dominant spoilage bacteria significantly affected the composition of volatile components in goose breast at the end of storage, resulting in higher proportions and contents of esters and ketones than fresh goose breast. Orthogonal partial least squares discrimination analysis (OPLS-DA) showed that methyl palmitoleate, methyl palmitate, ethyl oleate, methyl linoleate, ethyl linoleate, ethyl palmitoleate, 3-hydroxy-2-butanone, methyl trans-oleate, ethyl trans-oleate and neopentyl hexanoate were the major contributors to the volatile flavor of spoiled goose breast.
Nutrition & Hygiene
Anti-Aging Effects of Two Tocopherol Ester Derivatives on D-Galactose-Induced Aging in Mice
CHEN Weili, BEI Ling, YANG Yang, WANG Biying, LI Jiaxu, KAN Xutian, LI Wenzhi, DU Bing
2024, 45(6):  97-104.  doi:10.7506/spkx1002-6630-20221220-203
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In order to explore the anti-aging effects of two tocopherol ester derivatives, the in vitro antioxidant capacity of D-α-tocopherol acetate and DL-α-tocopherol acetate was determined. A mouse model of D-galactose-induced was created and intervened with each of the tocopherol ester derivatives for 42 days. Changes in aging related indicators were analyzed. The results showed that the hydroxyl radical scavenging capacity, and the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging capacity, Fe2+ chelating capacity, and total reducing power of the two tocopherol ester derivatives were better than those of vitamin C in the concentration range of 0.1 to 0.3 mg/mL. Compared with the aging model group, after intervention with tocopherol ester derivatives, the content of malondialdehyde (MDA) in serum decreased significantly (P < 0.05, P < 0.01, P < 0.001, and P < 0.000 1), and glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (T-AOC) increased significantly (P < 0.05, P < 0.01, P < 0.001, and P < 0.000 1). The serum levels of inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), and liver function indexes including aspartate aminotransferase (AST) and alanine aminotransferase (ALT) decreased significantly (P < 0.05, P < 0.01, P < 0.001, and P < 0.001). Moreover, the relative mRNA and protein expression levels of nuclear factor-E2-related factors (Nrf2), quinone oxidoreductase (NQO1) and heme oxygenase 1 (HO-1) in the mouse liver were enhanced. DL-α-tocopherol acetate increased the relative mRNA expression of Nrf2, NQO1 and HO-1 by 514.08%, 461.78% and 515.32%, respectively, and their relative protein expression by 620.00%, 988.89% and 1 200.00%, respectively (P < 0.000 1). To sum up, the two tocopherol ester derivatives have anti-aging effects on D-galactose-induced aging in mice, DL-α-tocopherol acetate being more effective than D-α-tocopherol acetate, and their anti-aging effects may be related to the regulation of the Nrf2 signaling pathway.
Protective Effects of Different Pine Pollen Extracts against Cyclophosphamide-Induced Ovarian Damage in SD Rats
LIU Qisong, CHEN Yang, YANG Changjun, HE Yujie, CHEN Qiuming, HE Zhiyong, WANG Zhaojun, CHEN Jie, ZENG Maomao
2024, 45(6):  105-112.  doi:10.7506/spkx1002-6630-20230504-022
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In this study, the contents of total sugars, crude polysaccharides, total phenols and total flavonoids in the aqueous and ethanol extracts of pine pollen, the large molecules isolated from the aqueous extract (> 5 kDa), and the small molecules isolated from the ethanol extract (< 5 kDa) were determined, and their protective effects on ovarian injury induced by cyclophosphamide in SD rats were explored. The results showed that compared with the model group, the ethanol extract and its small molecule fraction effectively increased the ovarian index, the number of mature follicles, the ovarian antioxidant enzyme activities total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) (by 16.03%, 25.81%; 138.42%, 237.09%; 104.31%, 109.90%; and 91.62%, 120.63%, respectively), and anti-apoptotic protein expression. In addition, they inhibited atretic follicles and ovarian lipid oxidation, as evidenced by a decrease in the content of malondialdehyde (MDA) by 53.42% and 48.43%, respectively; the effect was more pronounced than that of the aqueous extract and its large molecule fraction, while the aqueous extract and its large molecule fraction could protect the ovaries by reducing the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) activity. This study provides a theoretical basis for further investigation of the mechanism of the ovario-protective effect of pine pollen and also provides technical guidance for the development of new products based on pine pollen extracts.
Inhibitory Effect and Mechanism of Lactobacillus reuteri on Inflammation and Apoptosis of Intestinal Epithelial Cells
CHEN Peng, ZHONG Yuna, YU Liwen, HU Jin, XIE Meiying
2024, 45(6):  113-119.  doi:10.7506/spkx1002-6630-20230427-261
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Objective: To investigate the effect and mechanism of Lactobacillus reuteri on the inflammatory response and apoptosis of intestinal epithelial cells. Methods: Immunofluorescence and enzyme linked immunosorbent assay (ELISA) were used to detect the effect of L. reuteri on the inflammatory response and apoptosis of intestinal epithelial cells. Bioinformatics analysis, real-time polymerase chain reaction (PCR) and the dual-luciferase reporter gene assay were used to analyze downstream miRNA expression under the action of L. reuteri. The downstream target gene of miR-196a and its function were investigated using the dual-luciferase reporter gene assay and Western blot (WB). Results: L. reuteri inhibited inflammatory responses and apoptosis induced by lipopolysaccharide (LPS) in intestinal epithelial cells by up-regulating miR-196a. miR-196a could protect intestinal epithelial cells by targeting the expression of programmed cell death factor 4 (PDCD4). Conclusion: L. reuteri could inhibit the expression of the PDCD4 gene through miR-196a, thereby alleviating the inflammatory response and apoptosis of intestinal epithelial cells.
Effects of Total glycosides of Cistanche deserticola on HepG2 Hepatoma-Bearing Mice
FENG Duo, WANG Jing, JIANG Yongjun, ZHOU Shiqi, DUAN Hao, LI Jingyuan, YAN Wenjie
2024, 45(6):  120-129.  doi:10.7506/spkx1002-6630-20230509-072
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To study the anti-tumor effect of Cistanche deserticola in Balb/c mice, tumor-bearing nude mice subcutaneously inoculated with HepG2 liver cancer cells were administered with total glycosides (TG) of C. deserticola at different doses by gavage. The pathological changes in the liver and tumors, the proliferation capacity of splenic lymphocytes, and antioxidant indicators in the liver were detected. Metabolomics and 16S rDNA sequencing were used to analyze the changes in metabolites and microbial community composition in the intestinal contents of mice. Results showed that TG inhibited the growth of tumor in nude mice without affecting the normal growth and development of the mice and without any toxic side effects. As the dose of TG increased, the structure of hepatocytes in liver tissues became intact, the degree of pathological changes gradually reduced, the distribution of tumor cells became sparser, and the degree of vacuole deformation increased, which was accompanied by the occurrence of necrosis, indicating that TG could protect the liver and simultaneously inhibit the growth of tumor. TG alleviated liver lesions in mice, as evidenced by increased levels of catalase (CAT) and glutamic-pyruvic transaminase (GPT) and decreased levels of aspartate aminotransferase (GOT) and alkaline phosphatase (AKP). With increasing TG dose, the proliferative capacity of lymphocytes also increased, indicating that TG could exert an anti-liver cancer effect by improving immune function in mice. In addition, TG could inhibit the progression of liver cancer by regulating the levels of metabolites and improving the composition of the intestinal microbiota. Therefore, TG of C. deserticola has an anti-liver cancer effect by improving oxidative stress resistance, regulating immune capacity, improving the metabolic profile and regulating intestinal microbial balance.
Component Analysis
Multivariate Analysis and Discrimination of Quality Factors of Xiangcha Tea
MA Junhui, TONG Chen, FENG Haiqiang, LI Qian, WANG Yu, LUO Liewan, WANG Xiaochang, LIN Jie
2024, 45(6):  130-135.  doi:10.7506/spkx1002-6630-20230108-054
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In this study, 50 samples of Zhejiang Xiangcha tea, a representative of bulk green tea, from four varieties grown in three regions in Zhejiang province were collected and investigated. Correlation analysis among physicochemical indexes, catechin components, sensory factors and local wholesale prices was performed. The characteristic quality factors were selected and geographical origin and varietal discrimination were conducted by linear discriminant analysis (LDA) and random forest regression (RF-R). Moreover, this study attempted to establish a reference wholesale price prediction model. The results showed that the contents of free amino acids and caffeine were significantly correlated with several sensory factors, which were the key physicochemical factors for the formation of the flavor quality of Xiangcha tea. The contents of free amino acids and catechins and the ratio of phenol to ammonia were the origin-related factors. There were highly significant varietal differences in the overall sensory score, appearance, and sensory score for taste of Xiangcha tea, and significant differences in the aroma and the sensory score of brewed tea leaves. LDA demonstrated clear clustering of tea samples from each county and the feasibility of discriminating tea samples from different counties but not from different varieties. The reference wholesale price prediction mode developed by RF-R had good fitness (R2 = 0.867, mean absolute error = 7.907). The relative importance of factors for price fitting was ranked as follows: appearance > overall sensory score > aroma > infusion color > sensory score of brewed tea leaves > taste > amino acids > water extract > phenol to ammonia ratio > caffeine > tea polyphenols. The results of this study will guide the quality factor analysis, geographical origin traceability, varietal discrimination and trade reference pricing of tea.
Physicochemical Properties and Flavor Components of Four Foxtail Millet Bran Fractions
WANG Yunting, ZHANG Aixia, ZHAO Wei, LIU Jingke
2024, 45(6):  136-143.  doi:10.7506/spkx1002-6630-20230705-037
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Millet bran with different degrees of milling was used as raw materials, the differences in nutritional composition, physicochemical properties, and volatile components of different foxtail millet bran fractions were explored by measuring nutritional composition, water distribution, hydration characteristics, chromaticity, gelatinization characteristics, and volatile components. The results showed there were significant differences in content of fat, protein, ash, starch, and water among the four types of foxtail millet bran (S1–S4). S3 millet bran contained 10.96% protein and 26.05% fat, with the highest nutritional value. Meanwhile, S3 millet bran had excellent characteristics such as strong fluidity, strong foaming ability (5.54%), and high stability (82.86%), but high content of water and oil were not conducive to the storage of S3 millet bran. Correlation analysis shows that starch and protein directly affected the processing properties of millet bran (hydration characteristics, foaming properties, etc.). In addition, 72, 47, 70, and 51 volatile substances were detected in the four types of millet bran (S1–S4), respectively. There were 10 different volatile substances in 4 types of millet bran. Six compounds including methyl hexanoate, hexanal, and methyl palmitic acid had the highest content in S1 millet bran, and the other 4 compounds including dodecane and n-hexanol had the highest content in S2 millet bran. The odor activity value (OAV) of nonanal in four types of millet bran was 702, 444, 110, and 51, respectively, which could be used to effectively distinguish these foxtail millet bran fractions. This study is conducive to the precision separation process and selective use, which can maximize the utilization of resources.
Effect of Membrane Separation on Chemical Composition and Antioxidant Activity of Water Extracts from Different Kinds of Tea from Fujian
LIN Qingxia, WANG Lili, SONG Zhenshuo, CAI Shuxian, LIU Zhonghua, CHEN Lin
2024, 45(6):  144-152.  doi:10.7506/spkx1002-6630-20230412-107
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This study was done in order to investigate the changes of the major biochemical components and in vitro antioxidant activity of the water extracts from different kinds of tea during the process of their multistage membrane separation, ultrafiltration membranes with molecular masses cut-off (MMCO) of 20, 10, and 3.5 kDa, respectively were successively used to separate the water extracts from the major kinds of tea in Fujian including green tea, white tea, oolong tea from south Fujian, oolong tea from north Fujian, and black tea into fractions with different molecular masses. The fractions were spray dried and investigated for their ultraviolet (UV) spectra, biochemical compositions and in vitro antioxidant activity. The results showed that the UV absorption spectra of all samples were similar, exhibiting two obvious peaks at 210 and 274 nm. Absorbance at 274 nm exhibited a significant positive correlation with the contents of free amino acids (FAAs), caffeine (CAF), gallic acid (GA) and epicatechin gallate (ECG), and a significantly negative correlation with the contents of epigallocatechin (EGC) and epicatechin (EC). The distribution of biochemical components and the changes in antioxidant activity in vitro were affected by membrane separation, among which, the 20 kDa MMCO membrane had the most pronounced impact. The retentate from black tea after 20 kDa MMCO membrane ultrafiltration had the highest antioxidant activity in vitro, while the antioxidant activity of the permeate was lower than that of the permeate from the other kinds of tea. The biochemical components and antioxidant activity in vitro varied significantly among different types of tea samples, and the changes in biochemical components and antioxidant activity during the membrane separation process were not completely consistent. The water extract from black tea showed the greatest changes after 20 kDa MMCO membrane ultrafiltration. These results could provide a scientific basis for the membrane separation of aqueous extracts from different types of tea.
Glycerin Extraction Combined with High Performance Liquid Chromatography-Tandem Mass Spectrometry for Determining the Contents of Seven Types of Chemical Components in Tea and Its By-Products
GUAN Mengdi, ZHENG Yaru, YANG Zhulin, LI Huimin, LOU Huaqiao, YANG Yubing, LI Jiamei, YI Lunzhao, LI Siyu, HU Yongdan, REN Dabing
2024, 45(6):  153-163.  doi:10.7506/spkx1002-6630-20230616-135
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In this study, glycerin was used instead of traditional solvents such as methanol in combination with ultrasonic treatment for the high-efficiency extraction of multiple chemical components from tea. Furthermore, a quantitative analytical method for 130 chemical components belonging to seven classes in tea and its by-products was developed using ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-QQQ-MS/MS). The results showed that the extraction efficiency of glycerol was comparable to that of methanol and ethanol, and significantly better than that of water. The developed method had high sensitivity (limit of detection of 0.000 1-4.332 1 mg/kg) and accuracy (recoveries of 80.10%–121.12%). Appling this method to real samples, the content of each component varied greatly among different types of tea and by-products. Compared with tea samples, tea residue, a tea by-product, contained higher contents of caffeine, catechin and theanine, indicating the potential value of this by-product.
Simultaneous Direct Determination of Various Trace Aroma and Flavor Substances and Derivatives in Baijiu by UPLC-HRMS
YANG Junlin, YIN Yanyan, YIN Yanshun, YANG Shaojuan, TIAN Dongwei, XIE Dan, YOU Xiaolong, WU Cheng, HU Jianfeng, ZHANG Deqin
2024, 45(6):  164-174.  doi:10.7506/spkx1002-6630-20230512-105
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A rapid and accurate qualitative and quantitative method based on ultra-high performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS) was established for the determination of various trace aroma and flavor substances and their derivatives in baijiu. Samples were centrifuged at high speed, filtered and separated on a Hypersil Gold C18 (150 mm × 2.1 mm, 1.9 μm) column before analysis. The results showed that the pretreatment process allowed multi-component analysis of baijiu without extraction using ethanol or other organic solvents within 16 minutes. The calibration curves established using a mixed standard solution of 17 amino acids, 4 bioamines and 11 non-volatile organic acids exhibited good linearity (R2 > 0.990), and the detection limits and quantitation limits were relatively low for all analytes, which meet the requirements of the compositional analysis of baijiu. The average recoveries for all analytes were 71.92%–117.45%, with relative standard deviations (RSDs) of 0.46%–5.48%. The developed method had good recovery, precision, and stability for all analytes. Therefore, this method has the advantages of simple operation, high sensitivity, and good repeatability, and is of reference significance for the analysis of the types and contents of other non-volatile flavor substances in baijiu.
Food Engineering
Comparative Effects of Electron Beam Irradiation and Ultra-high Pressure Treatment on the Flavor of Jujube pulp
CHEN Meiling, JIAN Lei, YUAN Qiuyan, JIA Mingyue, GUI Xiangru, XU Huaide
2024, 45(6):  175-182.  doi:10.7506/spkx1002-6630-20230605-033
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This study investigated the effects of pasteurization (80 ℃ for 30 min), electron beam irradiation (3, 5 and 7 kGy) and ultra-high pressure treatment (400, 500 and 600 MPa for 6 min) on the flavor of jujube pulp. Untreated samples were used as control. The content of taste compounds such as free amino acids and reducing sugar was determined, and flavor quality was evaluated by electronic nose and electronic tongue and sensory evaluation. The results showed that compared with the control sample, free amino acid contents were significantly reduced by pasteurization and electron beam irradiation, and the contents of bitter amino acids such as arginine, valine and leucine were significantly increased by pasteurization. Electron beam irradiation and ultra-high pressure treatment could significantly increase the content of fructose in jujube pulp. Significant differences in electronic nose sensor responses were found among the eight groups. The electron tongue results showed significant differences in taste characteristics between the electron beam irradiated, ultra-high pressure treated and the control samples, while the taste characteristics of the pasteurized samples were closer to those of the control group. In addition, the samples treated with electron beam irradiation had higher sensory values for taste, color and reconstitutability than the other treatments. In conclusion, both electron beam irradiation and ultra-high pressure treatment could effectively improve the flavor quality of jujube pulp.
Effect of Ultrasound Treatment Time on Physicochemical and Structural Properties of Lotus Root Starch
LIAO Xueqin, WANG Nan, HU Rong, XUE Bingjie, ZHANG Fusheng, ZHENG Jiong
2024, 45(6):  183-191.  doi:10.7506/spkx1002-6630-20230424-235
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This study investigated the effects of different durations of ultrasound treatment (0, 10, 20, 30, 40 and 50 min) on the gelatinization, rheological properties, crystal structure, short-range ordered structure, and microstructure of lotus root starch (LS). The results showed that the molecular chain swelled and entanglement increased after ultrasonic treatment, and the gelatinization viscosity increased up to (6 059 ± 31) mPa·s. Cracks, and collapses and holes appeared on the surface of starch particles, which promoted the entrance of water molecules and increase the viscoelasticity. Ultrasound treatment destroyed the α-1,6-glycosidic bonds of starch molecules, and broke some branches to form short starch chains, which were rearranged into ordered structures. The number of short-range ordered structures increased, and the R1 047/1 022 ratio increased by 3.20%. Short-time ultrasonic treatment (30 min) enhanced the interaction between starch molecules, making the double helix structure more ordered and compact and increasing the Tp and ΔH by 11.09% and 89.21%, respectively. Long-time ultrasonic treatment (40–50 min) was not conducive to the formation of ordered structures. The results of this study can provide a theoretical basis for the application of ultrasonic in regulating the physicochemical properties and multi-scale structure of starch.
Effects of Thawing Methods on Eating Quality of Salted Crab
SHANG Jiayu, XU Xiang, XU Dalun, GU Guizhang, ZOU Zuquan, ZHANG Jinjie
2024, 45(6):  192-198.  doi:10.7506/spkx1002-6630-20230525-241
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In order to investigate the effects of different thawing methods on the eating quality of frozen salted crab and further to select the best thawing method, this study compared and analyzed the thawing curves using five thawing methods including low temperature thawing, room temperature thawing, running water thawing, ultrasonic thawing and pulsed magnetic field assisted thawing, and tested the quality attributes of the thawed samples by sensory evaluation and electronic tongue. Besides, the contents of proteins and their degradation products as well as flavor nucleotides were measured. The results showed that ultrasonic and pulsed magnetic field assisted thawing were the most time-saving (10.4 and 26.2 min, respectively), and low temperature thawing was the most time-consuming (312.6 min). The sensory scores for color, texture and odor of crab meat thawed by pulsed magnetic field were the highest, and the sensory score for taste of crab meat thawed by ultrasonic was the highest. The results of electronic tongue showed that the quality of salted crab meat treated by low temperature thawing, pulsed magnetic field assisted thawing and ultrasonic thawing was closer to each other, but significantly different from that of salted crab meat treated by running water thawing and room temperature thawing. The moisture content of salted crab meat thawed by ultrasound was the highest (84.37%), while the proteolysis index of salted crab meat thawed by pulsed magnetic field was the lowest (13.83%), and salted crab meat thawed by flowing water had the lowest moisture content (77.36%) and the highest proteolysis index (16.64%). The total free amino acid content of low-temperature thawed salted crab meat was the highest (2 885.78 mg/100 g). The contents of glutamate, glycine and alanine in salted crab meat thawed by pulsed magnetic field and ultrasonic were similar (97.50 vs 92.30 mg/100 g, 665.80 vs 642.40 mg/100 g, and 487.20 vs 490.50 mg/100 g, respectively, which were significantly higher than those of salted crab thawed by the other three methods. The different thawing methods had significant effects on flavor nucleotides in salted crab meat. Higher contents of flavor nucleotides were detected in salted crab meat thawed by ultrasound and pulsed magnetic field, with the highest equivalent umami concentration (EUC) being found in pulsed magnetic field thawed crab meat (44.38 g/100 g). Therefore, pulsed magnetic field thawing was the most suitable thawing method for frozen salted crab.
Effects of Homogenization and Sterilization Conditions on microencapsulation and Storage Stability of Walnut Oil
WANG Mingming, CHEN Yinyan, YU Zhijin, SHENG Jun, ZHAO Cunchao
2024, 45(6):  199-207.  doi:10.7506/spkx1002-6630-20230605-037
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In order to study the correlation between emulsion properties and microencapsulation rates and surface oil contents under different homogenization and sterilization conditions, the effects of emulsion stability, particle size, and particle size distribution on microencapsulation efficiency under different conditions were measured using a LUMiSizer 611 dispersion analyzer, and the morphological properties and storage stability of microcapsules under optimal conditions were analyzed. The results showed that the homogenization pressure and temperature and the sterilization conditions that provided the smallest emulsion stability index and average particle size were 40 MPa, 65 ℃ and 85 ℃/15 min, respectively. Under these conditions, particle size distribution was less scattered, and encapsulation rates of 95.38%, 97.12% and 94.23% were obtained, respectively. The average particle size of walnut oil microcapsules was 6.62 μm, with a surface oil content of 1.03% and an encapsulation rate of 96.41%. The surface and internal structure of the microcapsules were found to be good by scanning electron microscopy (SEM) indicating good encapsulation efficiency. Under accelerated storage conditions, walnut oil microcapsules showed better stability than free walnut oil. After 35 days of storage under different conditions, the reduction in the retention rate of walnut oil microcapsules varied, and the highest retention rate was achieved under the conditions of low temperature, darkness, and no oxygen or low oxygen concentration. This study could provide a theoretical basis for the selection and application of homogenization and sterilization processes for walnut oil emulsion and microcapsule products.
Inhibitory Effects of Different Pretreatment Methods on Oil Adsorption Characteristics of Formulated French Fries
WANG Zhizhen, LI Wenzhao, LI Yushuang, LU Xiao, XU Yanpeng, ZHANG Yaxu, LIU Xinyang, RUAN Meijuan
2024, 45(6):  208-215.  doi:10.7506/spkx1002-6630-20230901-011
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This study aimed to explore the effects of hot air-drying pretreatment (60, 90 and 120 min) and baking pretreatment (24, 27 and 30 min) on reducing oil adsorption by formulated French fries and the underlying effects and to determine the optimal pretreatment method. The results showed that compared with the untreated samples, the oil contents after hot air drying and roasting pretreatment were decreased by 5.37%–15.75% and 16.30%–16.51%, respectively (P < 0.05). We found that the moisture contents of the pretreated samples and the oil contents after frying were reduced compared with those of the control group, and showed a linear positive correlation with each other. Low-field nuclear magnetic resonance (LF-NMR) analysis showed that the content of free water was greatly reduced after pretreatment, and the free water was partially transformed into bound water and semi-bound water. Magnetic resonance imaging (MRI) analysis found that the distribution of oil on the surface and inside of the samples after baking pretreatment was less than that after hot air-drying pretreatment. Confocal laser scanning microscope (CLSM) observation showed that a small amount of oil was distributed in the gap between starch cells after baking pretreatment, and the amount of starch-lipid complexes produced in baked samples was significantly less than those in hot air-dried and untreated samples. Scanning electron microscope (SEM) showed that compared with hot air-drying pretreatment, the surface roughness of samples and the number of cracks and pores on the surface were reduced after baking pretreatment. Therefore, pretreatment could inhibit oil adsorption by formulated French fries by changing the initial moisture content, moisture state, surface microstructure and starch characteristics. The effect of baking pretreatment was more pronounced than that of hot air-drying pretreatment. Taking the sensory evaluation results into consideration, 27-min baking pretreatment was selected as the optimal pretreatment method to prepare low-oil quality potato snacks.
Packaging & Storage
Proline Metabolism of Different Varieties of Hami Melon Fruits in Response to Low Temperature
BI Ying, WANG Xinyu, LI Hui, HUANG Shuai, ZHANG Qi, LEI Yaxin, WANG Xue, WANG Fuxin, XU Wenchang, WANG Jing
2024, 45(6):  216-224.  doi:10.7506/spkx1002-6630-20230505-039
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In order to investigate the change in proline metabolism of two varieties of Hami melon fruits during low-temperature storage, ‘Xizhoumi 25’ and ‘Gashi’ melons were pre-cooled for 24 h and then placed for up to 42 days in a mechanical cold storage at (3.0 ± 0.5) ℃. Chilling injury symptoms were recorded, and chilling injury index, free proline content and proline metabolism-related indexes were measured every seven days . The results showed that the symptoms of chilling injury in ‘Gashi’ melon were significantly milder than those in ‘Xizhoumi 25’ melon, and as the storage time increased, free proline content, Δ1-pyrrolidine-5-carboxylic acid synthase (P5CS) activity, ornithine transaminase (OAT) activity and their relative gene expression increased significantly for both varieties; all these indicators were significantly higher in ‘Gashi’ melon than ‘Xizhoumi 25’ melon. The activity and relative gene expression of proline dehydrogenase (ProDH) decreased, indicating that both varieties of Hami melon fruits could resist chilling injury by increasing the free proline content and the activities of P5CS and OAT, the key enzymes for proline synthesis, and decreasing the activity of ProDH, the key enzyme for proline degradation. The metabolomics study revealed that the amino acid content of ‘Xizhoumi 25’melon decreased when the chilling injury became more serious, while the amino acid content of ‘Gashi’ melon showed an opposite trend. Whole gene synthesis of CmP5CS, a key enzyme gene involved in the proline metabolic pathway of Hami melon fruits, revealed that the Hami melon CmP5CS gene had the closest relatedness to melon (LOC103485529) P5CS, indicating functional similarity between them.
Effect of Glassy State and Liquid Nitrogen Quick Freezing on the Quality Characteristics of Blueberries
HUANG Bifei, LI Yang, HU Zexi
2024, 45(6):  225-232.  doi:10.7506/spkx1002-6630-20230629-236
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The glass transition temperature Tg’ of ‘Northcountry’ blueberries was determined according to its state diagram. Using Tg’ as the freezing end point, blueberries were frozen at −80 ℃ using an ultra-low temperature freezer (RF−80 ℃), or at −80, −100 or −120 ℃ by direct immersion in liquid nitrogen (LN−80 ℃, LN−100 ℃, and LN−120 ℃, respectively). Freezing curves, juice loss, hardness, nutrient contents, cell membrane integrity, enzyme activities and microstructure were measured to investigate the effects of liquid nitrogen quick freezing combined with Tg’ on the quality characteristics of blueberries. The results showed that the Tg’ of blueberries was −52.55 ℃; compared with RF-80 ℃, the quality of liquid nitrogen frozen blueberries was better maintained. The freezing time of liquid nitrogen quick freezing was significantly shortened, the frozen fruit lost less juice after thawing, and the hardness was better maintained. The contents of soluble solids, titratable acid, ascorbic acid and anthocyanin were closer to those of fresh fruit, the relative conductivity and malondialdehyde (MDA) content were lower, the integrity of the cell membrane was less broken, the activities of peroxidase (POD) and polyphenol oxidase (PPO) were lower, and the microstructural compactness and integrity were stronger. The lower the ambient temperature of liquid nitrogen quick freezing, the better the freezing effect, and LN-120 ℃ minimized the quality deterioration of frozen blueberries. In conclusion, liquid nitrogen quick freezing significantly increased the freezing rate, and its combined with Tg’ helped to maintain good quality of frozen blueberries. The results of this study can provide a theoretical basis for the selection of blueberry freezing conditions.
Antibacterial Effect and Mechanism of Chitosan/Curcumin Composite Photodynamic Coating on Staphylococcus aureus
ZHANG Pengmin, WANG Wenxiu, SUN Jianfeng, CHEN Zhizhou, MA Qianyun, WANG Jie
2024, 45(6):  233-243.  doi:10.7506/spkx1002-6630-20230429-284
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In this study, chitosan was used to enhance the photodynamic antibacterial effect of curcumin through ionic interactions, and the antibacterial mechanism of this coating against Staphylococcus aureus at the cellular level was clarified from the aspects of morphological characteristics, cell membrane function, energy metabolism, and DNA structure. The results showed that chitosan significantly improve the antibacterial effect. The number of S. aureus decreased by 6.89 (lg(CFU/mL)) after the coating solution containing 15 mg/L curcumin was exposed to 420 nm blue light for 5 min. Curcumin concentration and illumination time were the major factors affecting the antibacterial effect of this technique. The photodynamic inactivation treatment produced highly oxidizing reactive oxygen species (ROS), damaging the cell membrane and increasing membrane permeability, thus leading to the leakage of cell contents and cell shrinkage. It also led to an increase in intracellular ROS levels, which disrupted the structure of endogenous enzymes to trigger the breakdown of the bacterial defense system and the oxidative decomposition of macromolecules such as DNA and proteins, eventually causing the death of S. aureus. Therefore, chitosan/curcumin photodynamic coating has application potential in controlling foodborne pollution of S. aureus.
Safety Detection
Rapid Quantitative Authentication of Blended Vegetable Oil Quality by Raman Spectroscopy Coupled with a Selection Algorithm of Spectral Characteristic Intervals
WU Shengde, JIANG Xin, LI Aiqin, GUO Zhiming, ZHU Jiaji
2024, 45(6):  244-253.  doi:10.7506/spkx1002-6630-20230531-291
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In this study, a method for the rapid quantitative determination of the content of high-value vegetable oil in blended edible vegetable oils (BEVO) was proposed based on Raman spectroscopy and a selection algorithm of spectral characteristic intervals. First, the particle swarm optimization (PSO) and grey wolf optimization (GWO) algorithms were combined to develop a hybrid intelligent optimization algorithm called PSOGWO. Second, the PSOGWO algorithm and the combined moving window (CMW) strategy were combined to develop a novel spectral characteristic interval selection algorithm named PSOGWO-CMW. Third, blends of corn oil (CO) and extra virgin olive oil (EVOO) at different ratios were prepared, and then their Raman spectra were acquired. Using the Raman spectra as input variables, partial least squares regression (PLSR), PSO-CMW, GWO-CMW, and PSOGWO-CMW models were developed to predict the content of EVOO, and their performance was comparatively studied. The results showed that the PSOGWO-CMW model had the best prediction performance. The results of the proposed method for the content of EVOO in CO-EVOO blends were not significantly different from those of gas chromatography-mass spectrometry. In conclusion, this method is rapid and accurate, and can be used for rapid and quantitative determination of the content of high-value vegetable oil in BEVO.
Geographical Origin Identification of Lycium barbarum Fruit Using Hyperspectral Imaging Technology
YUAN Weidong, JIANG Hongzhe, YANG Shiyu, ZHANG Cong, ZHOU Yu, ZHOU Hongping
2024, 45(6):  254-260.  doi:10.7506/spkx1002-6630-20230620-159
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This study aimed to develop a method based on hyperspectral imaging (400–1 000 nm) combined with chemometrics to identify the diverse geographical origins of Lycium barbarum fruit. Hyperspectral images of L. barbarum fruit from Ningxia, Gansu, Inner Mongolia, Qinghai and Xinjiang were acquired, and spectral data was extracted from the region of interest (ROI) by threshold segmentation method. Multiple preprocessing methods were employed to eliminate the interference information from the spectra, and the results showed that the discriminant model based on normalized reflectance spectrum (NR) exhibited better performance. Furthermore, the successive projection algorithm (SPA), competitive adaptive reweighted sampling (CARS), particle swarm optimization (PSO), iteratively retaining informative variables (IRIV), and CARS + IRIV were used to select characteristic wavelengths. The results showed that the simplified model based on the wavelengths selected by CARS + IRIV had the best performance. In the models ranging from binary to quintuple classifications, the selected characteristic wavelengths accounted for only 15.6% to 27.7% of the full spectra. The prediction accuracy was 97.7%, 90.9%, 89.2%, and 87.1%, respectively. In addition, a confusion matrix was employed to visualize the optimal simplified classification model in order to intuitively distinguish the classification categories. Satisfactory sensitivity, specificity and Kappa coefficients were obtained in classifying L. barbarum. The results illustrated that hyperspectral imaging technology combined with chemometric methods could effectively identify the geographical origin of L. barbarum and provide crucial technical support for the development of the L. barbarum industry.
Development of a Detection Method for Quaternary Ammonium Compounds in Foods and Its Application to Commercial Foods and Dietary Samples in Beijing
XIE Yun, ZHOU Wei’e, XU Xiuli, ZHANG Jing, ZHANG Feng
2024, 45(6):  261-270.  doi:10.7506/spkx1002-6630-20230613-105
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An analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous detection of nine commonly used quaternary ammonium compounds (QACs) in various food matrices including vegetables, fruits, and aquatic products. The enrichment and purification of QACs were achieved using an improved quick, easy, cheap, effective, rugged and safe (QuEChERS) method, and the separation was performed on a BEH C18 column (100 mm × 3.0 mm, 1.7 μm) with gradient elution. QACs were detected using an electrospray ionization source in the positive ion mode. The limits of detection and quantification for the nine QACs in vegetables, fruits, and aquatic products were 0.2–5.0 and 1.0–10.0 μg/kg, respectively, and good linearity was observed for all analytes within their respective concentration ranges (R2 > 0.99). The recoveries for spiked samples were in the range of 65.24%–118.63% with relative standard deviations (RSDs) of 0.19%–6.77%. When the developed method was applied to commercial foods and dietary samples in Beijing, detection rates of 30.43% and 12% were obtained, respectively. The dietary risk of QAC residues was acceptable.
A Sandwich Immunosorbent Assay for 3-Amino-2-Oxazolidinone Following Derivatization
ZHANG Shiwei, WU Huiling, ZHOU Yingchun, WANG Bingzhi, YANG Xingxing, DU Yegang, TANG Lu, FENG Ronghu, GUO Jiping
2024, 45(6):  271-276.  doi:10.7506/spkx1002-6630-20230509-079
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In the present study, a sandwich enzyme-linked immunosorbent assay (ELISA) for 3-amino-2-oxazolidnone (AOZ) was developed. A novel derivatizing agent for AOZ was synthesized by linking 2-nitro-4-carboxybenzaldehyde and biotin through 1,6-hexanediol. During the sample pretreatment, the agent was added for AOZ derivatization with an efficiency of 89%. The monoclonal antibody (McAb) against AOZ was coated on the microplate and horseradish peroxidase-labeled avidin or anti-biotin antibody was used as a secondary conjugate in the ELISA method. From a practical perspective, the limit distances between the two epitopes in the double-antibody sandwich and antibody-avidin sandwich modes were 12 and 13 Å, respectively, and the ideal distances were 16 and 17 Å, respectively. The detection limits of the double-antibody sandwich and antibody-avidin sandwich modes were 1.8 and 0.8 pg/mL for AOZ, respectively. Compared with competitive ELISA, a 25-fold improvement in the sensitivity of the developed ELISA method was achieved. The average recoveries and average relative standard deviations (RSDs) were 73%–85% and 9.0%, respectively.
Reviews
Bigels in Food Field: from Composition to Application
ZHANG Qian, JIANG Ling, WANG Qiming, LEI Xiaojuan, MING Jian
2024, 45(6):  277-284.  doi:10.7506/spkx1002-6630-20230704-030
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Bigels are two-phase systems made up of oleogel and hydrogel sheared and mixed at a certain temperature. As amphiphilic semi-solid formulations, bigels have attracted wide attention due to their good stability, encapsulation characteristics and processing characteristics. Bigels have great potential in replacing traditional solid fats, improving the nutritional value of composite foods, and delivering bioactive substances. This article reviews the composition, synthesis methods and types of bigels, summarizes the significant progress in the application of bigels in the food field, and give an outlook on future prospects. It is our hope that this review will provide some guidance for further research and application of bigels in the food field.
Research Progress in the Regulatory Mechanism of Hydrocolloids on the Formation of Heat-Induced Myofibrillar Protein Gel
XU Yining, CAO Chuan’ai, HE Junjie, KONG Baohua, SUN Fangda, LIU Qian
2024, 45(6):  285-293.  doi:10.7506/spkx1002-6630-20230305-039
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Myofibrillar protein (MP) is an important protein in muscle, which can form a three-dimensional gel network structure upon heat treatment, ultimately influencing the quality of meat products. In the meat industry, hydrocolloids from different are incorporated to enhance the gel strength, water-holding capacity and functional properties of MP gel and finally optimize the quality of meat products. However, many factors affect the interaction between MP and hydrocolloids during the formation of heat-induced MP gelation, which in turn affects MP gel properties. In this article, the gelation mechanism of MP is systematically reviewed, the interaction mechanism between different hydrocolloids and MP is discussed, and the key factors influencing the regulatory effect of hydrocolloids on the formation of heat-induced MP gel and the effect of hydrocolloids on MP gel properties are summarized. We anticipate that this review will lay a theoretical foundation for establishing the key technical system based on hydrocolloids to regulate the quality of meat products and also provide technical guidance for future practical application.
Research Progress in Computational Fluid Dynamics in Fruit and Vegetable Drying
LI Mengqing, GENG Zhihua, ZHU Lichun, ZHANG Qian, YANG Xuhai
2024, 45(6):  294-305.  doi:10.7506/spkx1002-6630-20230306-055
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Drying is one of the major methods to extend the shelf life of fruits and vegetables. With the development of computer technology, computational fluid dynamics has been more and more widely used in the field of fruit and vegetable drying. This technique can simulate and predict the kinetic phenomena such as fluid flow, heat and mass transfer during the drying process of fruits and vegetables, and output the visualization results. Compared with traditional experiments, computational fluid dynamics has the advantages of energy saving, low cost, fast simulation speed and high flexibility. This article elaborates on the working principle of computational fluid dynamics in the field of fruit and vegetable drying, and reviews recent progress in the application of computational fluid dynamics to different fruit and vegetable drying methods as well as in the numerical modeling of coupled shrinkage. Finally, this review concludes with an outlook on future directions of computational fluid dynamics in the field of fruit and vegetable drying. It is our hope that this review will provide new insights and references for researchers.
Progress in Application of Magnetic Field Technology in the Processing of Agricultural Products
YAO Huangbing, JIN Yamei, ZHANG Lingtao, WU Shilin, ZHENG Zitao, WANG Ting, YANG Na, XU Xueming
2024, 45(6):  306-316.  doi:10.7506/spkx1002-6630-20230320-193
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With the development of modern agricultural technology and the in-depth research of the biological effect of magnetic field, magnetic field technology has been widely used in various fields of agricultural science. Appropriate magnetic field conditions such as proper intensity, waveform, and frequency can give rise to specific non-thermal effects on agricultural raw materials, which can regulate the metabolism, respiration and mass and heat transfer efficiency of biological tissues and cells, mainly by influencing water cluster, cell morphology, biomolecular activity, and gene expression. Therefore, compared with other physical processing methods, its effects manifest more slowly. Moreover, the same magnetic field parameters could show different effects on different processed objects. At present, magnetic field technology has been verified and applied in the field of agricultural products processing, mainly including assistance in the preservation, sterilization, fermentation, and extraction of agricultural products. This article summarizes the current status of research and application of magnetic field biochemical technology in agricultural products processing, and discusses the existing problems and future trends, which will provide a reference for researchers interested in the application of this technology in the agricultural field.
Advances in the Application of Carotenoids in Health Foods for Relieving Visual Fatigue
DUAN Hao, SONG Wei, WANG Feng, YAN Wenjie
2024, 45(6):  317-325.  doi:10.7506/spkx1002-6630-20230321-213
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Visual fatigue is an eye discomfort caused by a variety of factors and affects a wide range of the population. Studies have shown that reasonable dietary supplements can effectively improve eye discomfort caused by visual fatigue and even reduce the occurrence of visual fatigue. At present, the mechanisms of action of carotenoids represented by lutein in relieving visual fatigue has not been studied deeply, and few reviews have been conducted on their application in health foods for relieving visual fatigue. Therefore, this article describes the pathways of digestion, absorption, and metabolism of carotenoids in the human body, and reviews recent progress in carotenoids for relieving visual fatigue. Also, this article provides a statistical analysis of the application of carotenoid-rich ingredients in health foods for relieving visual fatigue in China, with a view to providing a reference and inspiration for researchers to develop health foods for relieving visual fatigue.
Research Progress on Changes in Eating Quality and Chemical Quality Attributes of Chicken during Freezing and Frozen Storage
HUANG Wenquan, KAN Qixin, LIU Guo, WANG Yanmei, YANG Shunde, SONG Mingyue, CAO Yong
2024, 45(6):  326-336.  doi:10.7506/spkx1002-6630-20230404-039
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As one of the major sources of protein in the human diet, chicken is characterized by high protein and low fat. Fresh chicken is susceptible to spoilage by microorganisms and enzymes during storage. Freezing is an effective way to extend the storage period of chicken, but ice crystals formed during the freezing process can negatively impact the chemical quality attributes of chicken, thereby affecting its eating quality. This article reviews traditional, modern, and emerging chicken freezing techniques, and elucidates the effects of freezing rate, freezing method, freezing temperature, freezing time, and freeze-thaw cycle on the quality of frozen chicken, with a focus on the changes in the eating quality (color, water-holding capacity, tenderness, and flavor) and chemical quality attributes (moisture, proteins, lipids, and pH) of chicken during freezing and frozen storage. It is our hope that this review will provide a theoretical reference for improving the key quality attributes of frozen chicken and extending its storage period.
Research Progress in Aroma Compounds of Blueberry Wine and Their Influential Factors
GUO Zhijun, YANG Hongli, MIN Zhuo, FANG Yulin
2024, 45(6):  337-359.  doi:10.7506/spkx1002-6630-20230105-027
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Blueberry wine is popular with consumers and has great market potential due to its rich nutrients and unique flavor. Aroma is an important indicator to measure the sensory quality of blueberry wine. However, there are some problems restricting the quality improvement of blueberry wine, such as insufficient studies on aroma components, unclear aroma characteristics and limited ways of aroma quality management. This article summarizes the composition, proportion and sources of volatile aroma components of blueberry wine, analyzes its key aroma substances and characteristic aroma based on odor activity value (OAV), and discusses the influence of cultivars, yeast, and process conditions on blueberry wine aroma. The purpose of this article is to offer a theoretical foundation for research on the aroma quality of blueberry wine aroma and for improving its processing technology.