Chang-Yu Zhou1,2, Dao-Dong Pan1,3, Yang-Ying Sun1, Chun-Bao Li2, Xing-Lian Xu2, Jin-Xuan Cao1, Guang-Hong Zhou2. 1. Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, Ningbo University, Ningbo, PR China. 2. Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Synergetic Innovation Center of Meat Processing and Quality Control, Nanjing Agricultural University, Nanjing, PR China. 3. Food Science and Nutrition Department, Nanjing Normal University, Nanjing, PR China.
Abstract
BACKGROUND: In order to evaluate the effect of cooking temperature on the nutrition quality of dry-cured hams, 60 biceps femoris samples from 16 Jinhua hams were divided into four groups (control, 70, 100 and 120 °C) and cooked for 30 min. Carbonyl content, sulfhydryl groups, surface hydrophobicity, microstructure, protein aggregation and digestibility of myofibrillar proteins were investigated. RESULTS: Cooking promoted carbonylation and decreased sulfhydryl groups in a temperature-dependent way. Scanning electron microscopy and Nile Red revealed that protein aggregation became a main phenomenon at 120 °C; it coincided with surface hydrophobicity. The increased carbonyl content and decreased sulfhydryl groups contributed to the formation of aggregates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles showed the initial difference in proteolysis rate among four groups. The in vitro digestibility of pepsin and of trypsin and α-chymotrypsin increased from the control to 100 °C and decreased from 100 to 120 °C. CONCLUSION: The increased digestibility could be attributed to the oxidation of proteins and exposing recognition sites of digestive enzymes, while the decreased digestibility was due to the formation of aggregates. Cooking was a main factor that affected the digestibility of Jinhua ham, and cooking at 100 °C could be an ideal way to gain the highest digestibility of Jinhua ham.
BACKGROUND: In order to evaluate the effect of cooking temperature on the nutrition quality of dry-cured hams, 60 biceps femoris samples from 16 Jinhua hams were divided into four groups (control, 70, 100 and 120 °C) and cooked for 30 min. Carbonyl content, sulfhydryl groups, surface hydrophobicity, microstructure, protein aggregation and digestibility of myofibrillar proteins were investigated. RESULTS: Cooking promoted carbonylation and decreased sulfhydryl groups in a temperature-dependent way. Scanning electron microscopy and Nile Red revealed that protein aggregation became a main phenomenon at 120 °C; it coincided with surface hydrophobicity. The increased carbonyl content and decreased sulfhydryl groups contributed to the formation of aggregates. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles showed the initial difference in proteolysis rate among four groups. The in vitro digestibility of pepsin and of trypsin and α-chymotrypsin increased from the control to 100 °C and decreased from 100 to 120 °C. CONCLUSION: The increased digestibility could be attributed to the oxidation of proteins and exposing recognition sites of digestive enzymes, while the decreased digestibility was due to the formation of aggregates. Cooking was a main factor that affected the digestibility of Jinhua ham, and cooking at 100 °C could be an ideal way to gain the highest digestibility of Jinhua ham.