食品科学 ›› 2021, Vol. 42 ›› Issue (19): 170-182.doi: 10.7506/spkx1002-6630-20200907-094

• 食品工程 • 上一篇    

超高压结合温热处理对脱脂乳透光率和粒径及蛋白溶解性的影响

胡志和,赵旭飞,鲁丁强,薛璐,贾凌云,程凯丽   

  1. (天津商业大学生物技术与食品科学学院,天津市食品生物技术重点实验室,天津 300134)
  • 发布日期:2021-11-12
  • 基金资助:
    天津市科技计划项目(17ZXYENC00130);天津市高等学校创新团队项目(TD13-5087)

Effect of Ultra-High Pressure Combined with Mild Heat Treatment on Light Transmittance, Particle Size and Protein Solubility in Skim Milk

HU Zhihe, ZHAO Xufei, LU Dingqiang, XUE Lu, JIA Lingyun, CHENG Kaili   

  1. (Tianjin Key Laboratory of Food Biotechnology, School of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin 300134, China)
  • Published:2021-11-12

摘要: 目的:研究高压结合温热(≤50 ℃)处理对脱脂乳粒径、透光率及蛋白溶解性的影响。方法:采用不同温度(常温、30、40、50 ℃)和压力(0.1~700 MPa)分别处理脱脂乳10~30 min,利用激光纳米粒度仪检测脱脂乳粒径变化,分光光度法检测透光率变化,考马斯亮蓝法测定可溶性蛋白质量浓度变化。结果表明,脱脂乳透光率在压力不高于100 MPa范围内不受温度、压力和处理时间的影响;在200~700 MPa范围内,常温条件下处理的脱脂乳透光率随压力的升高和处理时间的延长而增大,在700 MPa下处理20 min时透光率最大,增幅为1 011%;在30~50 ℃范围内,透光率随压力增大(200~700 MPa)呈现先升高后降低的趋势,在40 ℃、500 MPa下处理10 min时透光率增幅最大(537%),透光率受温度和保压时间的影响,且超高压结合温热处理脱脂乳透光率均高于未处理脱脂乳。在常温、0.1~400 MPa范围内,脱脂乳的中位径(Dx(50))随压力的增大而总体降低,在400~700 MPa范围内变化趋势平稳,但均小于未处理脱脂乳的Dx(50);30、40、50 ℃下,脱脂乳Dx(50)随压力增大呈现先升高后降低的趋势,分别在400~700、300~500、200~400 MPa范围内变化趋势平稳,且受时间影响较小。经高压处理的脱脂乳中可溶性乳蛋白(soluble protein,S-Pro)质量浓度总体呈增加趋势,且受压力、时间和温度的影响,在30 ℃、500 MPa下处理30 min,S-Pro质量浓度增幅最大(83.55%)。pH 4.6下可溶性蛋白(S-Pro-pH 4.6)质量浓度在压力不高于100 MPa时不受温度、压力和时间的影响;在200~700 MPa范围内,不同温度下,随压力升高和处理时间的延长,S-Pro-pH 4.6质量浓度呈现下降趋势。对各指标间相关性进行分析发现,透光率与Dx(50)间的相关性随温度升高减弱;透光率与S-Pro质量浓度呈正相关,与S-Pro-pH 4.6质量浓度呈负相关。S-Pro与S-Pro-pH 4.6之间呈负相关。结论:经超高压结合温热处理,能够引发脱脂乳透光率、粒径及蛋白溶解性的变化,且这些变化存在一定的相关性。

关键词: 超高压;温热;脱脂乳;透光率;粒径;蛋白溶解性;相关性

Abstract: The objective of this work was to explore the changes in the particle size of casein micelles, transmittance and protein solubility in skim milk induced by high pressure combined with mild heat treatment (≤ 50 ℃). Fresh skim milk was treated for 10–30 min at different temperatures (room temperature, 30, 40 and 50 ℃) and pressures (0.1–700 MPa). The particle size was measured by a Marvin laser nanometer, the transmittance was detected by spectrophotometry, and the content of soluble protein was determined by the Coomassie brilliant blue G250 method. Results showed that the transmittance of skim milk treated at pressure levels not exceeding 100 MPa was not affected by temperature, pressure and treatment time. The transmittance of skim milk treated at room temperature and in the pressure range of 200–700 MPa increased with the increase in pressure and pressure-holding time, and the maximum percentage increase of 1 011% was observed when skim milk was treated at 700 MPa for 20 min. Upon treatment at 30–50 ℃ and in the pressure range of 200 to 700 MPa, the transmittance first increased and then decreased with the increase in pressure, and the maximum increase of 537% occurred upon treatment at 500 MPa and 40 ℃ for 10 min. The transmittance was affected by temperature and pressure-holding time, and was higher than that of the untreated control. The median particle size (Dx(50)) of skim milk treated at room temperature decreased with the increase in pressure from 0.1 to 400 MPa, and then remained stable in the range of 400–700 MPa, which was smaller than that of the untreated control. Upon treatment at 30–50 ℃ and in the pressure range of 0.1–700 MPa, the Dx(50) showed a first increasing and then decreasing trend with the increase in pressure, and remained stable in the range of 400–700, 300–500 and 200–400 MPa, which was only slightly affected by treatment time. The content of soluble milk protein (S-Pro) in skim milk treated by high pressure showed an increasing trend, and it was affected by pressure, time and temperature. After treatment at 30 ℃ and 500 MPa for 30 min, the maximum percentage increase in the S-Pro content of 83.55% was obtained. The content of soluble protein at pH 4.6 (S-Pro-pH 4.6) was not affected by temperature, pressure and time when the pressure was low than 100 MPa. For each temperature, S-Pro-pH 4.6 content decreased with the increase in pressure in the range of 200–700 MPa and treatment time. The correlation analysis showed that the transmittance was correlated with Dx(50), and this correlation was weaker with increasing temperature. The transmittance was positively correlated with S-Pro content and negatively correlated with S-Pro-pH4.6 content. There was a negative correlation between S-Pro and S-Pro-pH 4.6 contents. Therefore, ultra-high pressure combined with mild heat treatment can cause changes in the transmittance, particle size and protein solubility of skim milk, and these changes are correlated with each other to some extent.

Key words: ultra-high pressure; mild heat; skim milk; transmittance; particle size; protein solubility; correlation

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