The Acute Effects of Low Temperature for Long Time Heat Treatment of Pork Semitendinosus on Satiety

Overview

Cooking meat at low temperatures for prolonged times is widely used among chefs and in food service due to the possibility to obtain a consistent and appealing eating quality. The method is generally termed low-temperature long-time (LTLT) cooking. In LTLT cooking, meat is vacuum-packed and heated at temperatures between 50°C and 65°C in a water bath for several hours. LTLT has several benefits - improved tenderness and juiciness, less cooking loss, better vitamin retention and uncompromised food safety. A recent PhD thesis concluded that one of the mechanisms behind the changes in eating quality during LTLT cooking was due to the proteolytic degradation in the muscle tissue. The activity of proteolytic enzymes has shown to be dependent on heating temperature and time where the cathepsins were found to remain active during heat treatment. At 58°C the cathepsin B+L activity is increased compared to 48°C and 53°C and at 55°C compared to 25°C, 40°C and 70°C. A prolonged heating time of 17 hours at 58°C has also shown to increase cathepsin B+L activity. The proteolytic degradation results in the occurrence of peptides and amino acids such as tryptophan, tyrosine, leucine and histidine which could lead to a faster degree of satiety when consumed. According to the aminostatic hypothesis by Mellinkoff, a rise in plasma amino acids elicited by protein ingestion could assist in the suppression of food intake and the onset of satiety. The investigators therefore hypothesize that the ingestion of LTLT cooked pork would induce a faster satiety response due to the higher availability of peptides and amino acids prior to digestion. An acute meal study will elucidate this. LTLT cooking will be performed by the "cook-chill" method to mimic real life where meat is rapidly chilled after heat treatment, stored at 0-2°C and reheated and browned prior to serving.