Evaluation of the secondary structure and digestibility of myofibrillar proteins in cooked ham

Abstract

The present study aimed to evaluate structure and digestibility of dry-cured ham in relation to different cooking temperatures (70, 100 and 120°C), and further assess the relationship between structure and digestibility. The secondary structure analysis showed that the content of α-helix decreased from 55.03% to 20.61%, accompanied by an increase in the content of β-sheet and random coil from the raw to 120°C. The digestibility showed that proteolysis rate of myofibrillar proteins by pepsin and trypsin & α-chymotrypsin (digestive enzymes) significantly increased to 0.62 and 0.51 at 100°C, compared with the raw. Odour and taste were susceptible to cooking temperature, and 100°C enhanced odour and taste attributes of ham. The changes of protein conformation were closely related to the digestibility. Correlation analysis further demonstrated that activities of digestive enzymes for proteins were negatively correlated with α-helical and β-sheet, and positively correlated with β-turn and random coil.