Higher protein digestibility of chicken thigh than breast muscle in an in vitro elderly digestion model

Seonmin Lee1, Kyung Jo1, Hyun Gyung Jeong1, Seul-Ki-Chan Jeong1, Jung In Park1, Hae In Yong1, Yun-Sang Choi2, Samooel Jung1,*
Author Information & Copyright
1Division of Animal and Dairy Science, Chungnam National University, Daejeon 34134, Korea
2Research Group of Food Processing, Korea Food Research Institute, Wanju 55365, Korea
*Corresponding Author: Samooel Jung. E-mail:

© Copyright 2022 Korean Society for Food Science of Animal Resources. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Sep 02, 2022 ; Revised: Dec 20, 2022 ; Accepted: Dec 20, 2022

Published Online: Dec 27, 2022


This study investigated the protein digestibility of chicken breast and thigh in an in vitro digestion model to determine the better protein sources for the elderly in terms of bioavailability. For this purpose, the biochemical traits of raw muscles and the structural properties of myofibrillar proteins were monitored. The thigh had higher pH, 10% trichloroacetic acid (TCA)-soluble α-amino groups, and protein carbonyl content than the breast (P<0.05). In the proximate composition, the thigh had higher crude fat and lower crude protein content than the breast (P<0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrillar proteins showed noticeable differences in the band intensities of tropomyosin α-chain and myosin light chain-3 between the thigh and breast. The intrinsic tryptophan fluorescence intensity of myosin was lower in the thigh than in the breast (P<0.05). Moreover, circular dichroism spectroscopy of myosin revealed that the thigh had higher α-helical and lower β-sheet structures than the breast (P<0.05). The cooked muscles were then chopped and digested in the elderly digestion model. The thigh had more α-amino groups than the breast after both gastric and gastrointestinal digestion (P<0.05). SDS-PAGE analysis of the gastric digesta showed that more bands remained in the digesta of the breast than that of the thigh. The content of proteins less than 3 kDa in the gastrointestinal digesta was also higher in the thigh than in the breast (P<0.05). These results reveal that chicken thigh with higher in vitro protein digestibility is a more appropriate protein source for the elderly than chicken breast.

Keywords: chicken breast; chicken thigh; protein digestibility; elderly digestion; dietary protein source