Amino Acid

Pork products have digestible indispensable amino acid scores that are greater than 100, but processing does not always increase amino acid scores

Pork is the most widely consumed animal meat in the world accounting for approximately 40% of the total global meat intake. Pork almost always undergoes some degree of processing prior to consumption. Consequently, thermal processing induces modification to the 3-dimentional structure of proteins, which may lead to increased digestibility of amino acids (AA).

Protein quality is evaluated in human foods by the digestible indispensable amino acid score (DIAAS) methodology, which can be described as the digestibility of individual dietary indispensable AA (IAA) compared with the same IAA in 1 of the 3 reference protein patterns established by the Food and Agriculture Organization of the United Nations (FAO). Values for DIAAS of bovine meat cooked by various techniques have been determined, yet to our knowledge, there are no reported DIAAS values for pork products and the IAA digestibility of pork after processing has not been reported.

Therefore, the objective for the present work was to determine DIAAS values for pork products, and to test the hypothesis that processing may increase protein quality.

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Effects of dietary leucine concentration on branched-chain amino acid metabolism in growing pigs

Leucine, Val, and Ile are categorized as the branched-chain AA (BCAA) because of the structural similarity of their side chains. All 3 BCAA share the enzymes that are involved in the first 2 steps of their catabolic pathway. The first step is a transamination step catalyzed by BCAA transaminase (BCAT) and producing branched-chain α-keto acids (BCKA). The second step is an irreversible degradation step catalyzed by branched-chain α-keto acid dehydrogenase (BCKDH). In the second step, Leu has been considered a key regulator as its BCKA metabolite (α-keto isocaproate) stimulates activation of the BCKDH complex in the liver. When excess Leu in diets is offered to pigs, degradation of all 3 BCAA may increase because of increased activity of BCAT and BCKDH. Leucine and Trp are both categorized as large neutral AA, and they share a common uptake pathway across the blood-brain barrier. Therefore, it is possible that excessive Leu may result in reduced Trp uptake into the brain due to competition for transporters, resulting in reduced serotonin synthesis.

 

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