FOOD SCIENCE ›› 2020, Vol. 41 ›› Issue (4): 7-14.doi: 10.7506/spkx1002-6630-20190717-230

• Food Chemistry • Previous Articles     Next Articles

Effects of Whey Protein Peptides on Oxidation Inhibition and Quality Improvement of Chopped Pork during Repeated Freezing-Thawing

PENG Xinyan, LIU Yuan, HE Hongjun, ZHANG Min, SHAO Lingjian, ZENG Yulong, WANG Xiaoyu   

  1. (1. College of Food Engineering, Ludong University, Yantai 264025, China;2. Bio-Nanotechnology Institute, Ludong University, Yantai 264025, China; 3. College of Life Sciences, Yantai University, Yantai 264005, China)
  • Online:2020-02-25 Published:2020-03-02

Abstract: The effects of whey protein hydrolysates (WPH) on the oxidation stability and quality of chopped pork during repeated freezing-thawing were examined. Different levels (5%, 10% and 15%) of WPH were added to the pork systems. Changes in thawing loss, total volatile base nitrogen (TVB-N) value, thiobarbituric acid reactive substances (TBARS) value, gel texture, protein carbonyl content, modulus loss and Raman spectrum were evaluated during nine freezing-thawing cycles. The results showed that before freeze-thawing, as far as all tested indexes were concerned there was no signi?cant difference between the treatment and control groups (P > 0.05). Thawing loss was increased from 2.67%?2.93% to 7.00%?12.4% after freeze-thawing cycles. Addition of 15% WPH significantly inhibited the increase in thawing loss and enhanced water-holding capacity (P < 0.05). After 7?9 cycles of freezing-thawing, 15% WPH could significantly inhibit the increase of TVB-N value, TBARS value and protein carbonyl content when compared with the blank control and native whey protein (NWP) groups. Texture profile analysis (TPA) indicated that hardness, springiness, chewiness and cohesiveness were significantly decreased with increasing cycles of freezing-thawing. Chewiness was increased significantly from 9.63 to 17 g with 15% WPH treatment after the 9th cycle, and springiness reached 0.69 after the 5th cycle, exceeding the 0.02% BHA group. The hardness and cohesiveness of both WPH and 0.02% BHA groups were significantly higher than those of the blank group. The TPA parameters could be improved by adding WPH, especially at higher levels. The rheological tests showed that modulus loss (G’’) values were declined with the addition of WPH (P < 0.05). Raman spectroscopic analysis revealed that the addition of WPH inhibited the transformation of α-helices into β-sheets effectively and protected the secondary structures of the protein. In summary, WPH could act as an antioxidant to inhibit oxidation and preserve the quality of chopped pork during repeated freezing-thawing.

Key words: whey protein polypeptides, antioxidant activity, chopped pork, repeated freezing and thawing, quality characteristics

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