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The degree of doneness affected molecular changes and protein digestibility of pork.

ABSTRACT: The degree of doneness has been shown to have a great impact on eating quality of meat, however, it is little known whether it affects protein digestibility of meat. In this study, we explored molecular changes and protein digestibility of pork under different degree of doneness. Pork chops were cooked in a 100°C water bath for about 26 min and a gradient decrease in doneness was obtained from outer to inner layers of samples. Compared with the raw samples, the cooked samples' active and total sulfhydryl contents, surface hydrophobicity, and turbidity increased but its solubility decreased. The inner layers with lower doneness contained higher α-helix, and fluorescence intensities of tryptophan and tyrosine residues than the outer layers with higher doneness. The pepsin and pancreatin digestibility of meat proteins in the inner layers were higher than those of the outer layers. Molecular simulation analysis showed that the most abundant protein in pork, i.e., myosin in the outer layers were more stable with an increased number of hydrogen bonds, making it difficult to be digested. These findings provided a new insight into the heterogeneity of meat nutritional quality due to the existence of doneness gradient.

SUBMITTER: Han Y

PROVIDER: S-EPMC9845567 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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The degree of doneness affected molecular changes and protein digestibility of pork.

Han Yu Y Liu Hui H Li Qian Q Zhao Di D Shan Kai K Ke Weixin W Zhang Miao M Li Chunbao C

Frontiers in nutrition 20230104

The degree of doneness has been shown to have a great impact on eating quality of meat, however, it is little known whether it affects protein digestibility of meat. In this study, we explored molecular changes and protein digestibility of pork under different degree of doneness. Pork chops were cooked in a 100°C water bath for about 26 min and a gradient decrease in doneness was obtained from outer to inner layers of samples. Compared with the raw samples, the cooked samples' active and total s ...[more]

PMID: 36687702

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Project description:The objective was to determine the effects of pH and color on sensory characteristics of boneless pork loin chops cooked to an internal endpoint temperature of 63 °C. Center cut loins (296 total) from barrows and gilts, 5 different sire lines, and a range in pH of 5.36 through 6.23 were used. Previously, ultimate pH was correlated with sensory characteristics of chops cooked to a medium (71 °C) degree of doneness. Additionally, increasing ultimate pH improved sensory tenderness and juiciness of loin chops cooked to a medium degree of doneness. However, in 2011, the United States Department of Agriculture Food Safety and Inspection Service reduced the recommended final internal cooking temperature of pork chops from 71 to 63 °C (followed by a 3-min rest). The effects of ultimate pH on sensory traits of pork chops cooked to a medium-rare (63 °C) degree of doneness are not known. Therefore, loins were categorized using historical categories based on ultimate pH: >5.95, n = 22; 5.80 to 5.95, n = 75; 5.65 to 5.80, n = 102; 5.50 to 5.65, n = 91; <5.50, n= 6. On 1-d postmortem, loins were evaluated for CIE instrumental L*, a*, b*, visual color, marbling, and subjective firmness. Then, loins were aged in vacuum packages at 4 °C until 16-d postmortem. After aging, loins were cut into 2.54-cm thick chops, vacuum-packaged, and frozen until sensory or instrumental tenderness analysis. One chop was also used to determine extractable lipid. Chops were weighed, cooked to 63 °C, cooled to approximately 23 °C, weighed again to determine cook loss, and then evaluated for Warner-Bratzler shear force. Another chop was cooked to 63 °C internal temperature and served warm to trained panelists to determine sensory traits. Coefficients of determination (R2) were calculated to determine the predictability of ultimate pH and instrumental color on sensory tenderness, juiciness, and flavor. A 1-way ANOVA and means separation test were used to determine specific differences among pH categories. Ultimate pH explained less than 5% of the variation in tenderness and less than 1% of the variation in juiciness or flavor. Furthermore, sensory tenderness did not differ (P > 0.05) among pH categories, except for chops with an ultimate pH > 5.95. Chops with a pH > 5.95 were at least 9.1% more tender (P < 0.05) than chops with a pH < 5.95. Visual and instrumental color were not predictive (R2 ≤ 0.03) of any sensory traits. Overall, pH does not influence sensory traits of pork chops cooked to medium-rare degree of doneness unless pH is at least 5.95.

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The degree of doneness affected molecular changes and protein digestibility of pork.

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The degree of doneness affected molecular changes and protein digestibility of pork.

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