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Title:Digestible indispensable amino acid scores for meat products
Author(s):Bailey, Hannah Marie
Advisor(s):Stein, Hans H
Contributor(s):Boler, Dustin D; Loor, Juan J
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):digestible indispensable amino acid scores
beef
pork
amino acid digestibility
protein quality
Abstract:Two experiments were conducted to determine the digestible indispensable amino acid scores (DIAAS) for pork and beef products using the pig as a model, and to test the hypothesis that various degrees of meat processing may increase the digestibility of amino acids (AA) and protein quality of meat as shown by an increase in DIAAS. In experiment 1, DIAAS values were determined for 9 pork products (i.e., raw belly, smoked bacon, smoked-cooked bacon, non-cured ham, alternatively cured ham, conventionally cured ham, medium loin, medium-well loin, and well-done loin). Ten female pigs (BW: 26.63 ± 1.62 kg) were surgically fitted with a T-cannula in the distal ileum and randomly allotted to a 10 × 10 Latin square design with 10 diets and ten 7-d periods; the initial 5 d were for adaptation to the diet and the following 2 d for 9 h of ileal digesta collection. Nine diets contained a single pork product as the sole source of crude protein (CP) and AA. A N-free diet was formulated to determine basal endogenous losses of CP and AA, enabling the calculation of standardized ileal digestibility (SID) of AA. The DIAAS values were calculated using the determined concentration of digestible indispensable AA (IAA) in each meat product and 2 reference protein patterns established by the Food and Agriculture Organization of the United Nations (FAO); 1) children 6 mo to 3 yr and 2) children > 3 yr, adolescents, and adults. All pork products had a DIAAS value greater than 100, regardless of the reference protein pattern and processing method. When compared with the 2 human AA requirement patterns, Val was the limiting AA in all pork products, except for smoked-cooked bacon, which was limiting in Trp for children 6 mo to 3 yr. Medium loin had the greatest (P < 0.05) DIAAS value for children 6 mo to 3 yr, and smoked-cooked bacon had the greatest (P < 0.05) DIAAS value for older children, adolescents, and adults. Among the pork bellies, smoked-cooked bacon had the greatest (P < 0.05) DIAAS value with no difference observed between raw belly and smoked bacon. The digestibility of IAA in smoked-cooked bacon was lower (P < 0.05) than for raw belly, but no differences were observed between the other bellies. Among the pork hams, alternatively cured ham had the greatest (P < 0.05) value for DIAAS with no difference observed between conventionally cured and non-cured ham. Alternatively cured and conventionally cured ham had greater (P < 0.05) digestibility of IAA compared with non-cured ham. The loin cooked to the medium degree of doneness had a greater (P < 0.05) DIAAS value than the loins cooked to medium-well and well-done degrees of doneness, with no differences observed between the DIAAS of medium-well and well-done loin, as well as no differences were observed in the digestibility of IAA among all loins. Results indicate that pork products are excellent quality protein sources and that processing may increase DIAAS. Experiment 2 was conducted to determine the DIAAS values for 8 meat products (i.e., salami, bologna, beef jerky, raw ground beef, cooked ground beef, medium-rare ribeye roast, medium ribeye roast, and well-done ribeye roast). Nine ileal-cannulated female pigs (BW: 35.50  3.77 kg) were randomly allotted to a 9 × 8 Youden square design with 9 diets and eight 7-d periods with ileal digesta collected for 9 h on d 6 and 7. Each of the 8 meat products were included in one diet as the sole source of CP and AA, and a N-free diet was formulated to determine basal endogenous losses of CP and AA. The SID of AA was calculated, and the concentration of digestible indispensable AA in each meat product was determined and compared with the 2 established reference protein patterns used in Exp. 1. The DIAAS was determined based on the limiting AA in the meat compared with the human AA requirements. For children 6 mo to 3 yr, sulfur AA were limiting in salami and beef jerky, Leu was limiting in bologna, cooked ground beef, and well-done ribeye roast, Trp was limiting in raw ground beef, and Val was limiting in medium-rare and medium ribeye roasts. Well-done ribeye roast and cooked ground beef had DIAAS values less than 100, but all other meat products had values greater than 100. Medium ribeye roast and bologna had the greatest (P < 0.05) DIAAS values followed by raw ground beef, salami, medium-rare ribeye roast, beef jerky, well-done ribeye roast, and cooked ground beef, respectively. For older children, adolescents and adults, sulfur AA were limiting in beef jerky, Leu was limiting in bologna, raw ground beef, and cooked ground beef, and Val was limiting in salami and the 3 ribeye roasts. All meat products had DIAAS values greater than 100, except cooked ground beef with a DIAAS of 99. Medium ribeye roast and bologna had the greatest (P < 0.05) DIAAS values followed by raw ground beef, salami, beef jerky, medium-rare ribeye roasts, well-done ribeye roasts, and cooked ground beef, respectively. The digestibility of most IAA was not different among salami, bologna, beef jerky, and cooked ground beef, but the digestibility of IAA in these products was less (P < 0.05) than in raw ground beef. The digestibility of IAA in medium-rare ribeye roast was not different from raw ground beef and well-done ribeye roast, but greater (P < 0.05) than in medium ribeye roast. Results from this experiment indicate that meat products generally provide high quality protein, however, overcooking may reduce IAA digestibility and DIAAS. In conclusion, curing and moderate cooking may increase DIAAS, whereas grinding meat prior to some processing methods or overcooking may reduce the digestibility of IAA and DIAAS of meat products.
Issue Date:2018-12-14
Type:Text
URI:http://hdl.handle.net/2142/102867
Rights Information:© 2018 Hannah Marie Bailey
Date Available in IDEALS:2019-02-07
Date Deposited:2018-12


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