Processing Stability of Antioxidant Protein Hydrolysates Extracted from Degreased Walnut Meal
Ting Lai 1, Zehua Lin 1, Rong Zhang 1, Xiaolei Guo 2,
Zhonghua Ma 2, Wenzhen Liao 1, Jiaoyan Ren 1, and
Xiao Hu 3
1. College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China
2. R&D Center, Infinitus (China) Co., LTD. Guangzhou 510665, China
3. South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
2. R&D Center, Infinitus (China) Co., LTD. Guangzhou 510665, China
3. South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China
Abstract—Degreased walnut meal was hydrolyzed by trypsin and the optimal hydrolysis conditions were at the enzyme to substrate of 9.2×105 U/g with the hydrolysis time of 30h. The effects of acidic/alkaline treatments on the antioxidant stability of WPH (liquid walnut meal protein hydrolysate), WPHP-s (spray-dried WPH sample) and WPHP-f (freeze-dried sample) were assessed. These samples were quite stable under acidic conditions, remaining approximately 90% of its original reducing power and 85% of its OH• scavenging activity. However, they were susceptible to alkaline treatments (at pH>10.0) and lost>50% of their antioxidant activities. In terms of heat processing, common pasteurization (65°C×30 min) or autoclaving sterilization (121°C×20 min) treatment did not show notably effects on the antioxidant activities of these three samples. Different drying methods (spray-drying or freeze-drying) demonstrated very slight influence on their structure and activities, as further confirmed by molecular weight distribution assay.
Index Terms—walnut meal, protein hydrolysates, drying methods, antioxidant activity, stability, molecular weigh
Cite: Ting Lai, Zehua Lin, Rong Zhang, Xiaolei Guo, Zhonghua Ma, Wenzhen Liao, Jiaoyan Ren, and Xiao Hu, "Processing Stability of Antioxidant Protein Hydrolysates Extracted from Degreased Walnut Meal," International Journal of Food Engineering, Vol. 2, No. 2, pp. 155-161, December 2016. doi: 10.18178/ijfe.2.2.155-161
Cite: Ting Lai, Zehua Lin, Rong Zhang, Xiaolei Guo, Zhonghua Ma, Wenzhen Liao, Jiaoyan Ren, and Xiao Hu, "Processing Stability of Antioxidant Protein Hydrolysates Extracted from Degreased Walnut Meal," International Journal of Food Engineering, Vol. 2, No. 2, pp. 155-161, December 2016. doi: 10.18178/ijfe.2.2.155-161
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