Abstract
Two experiments were conducted to test the hypothesis that processing of meat proteins increases the Digestible Indispensable Amino Acid Score (DIAAS). In Exp. 1, 10 pigs (26.62 ± 1.62 kg) with a T-cannula in the distal ileum were randomly allotted to a 10 x 10 Latin square with 10 diets and ten 7-d periods. In Exp. 2, 9 cannulated pigs (35.50 ± 3.77 kg) were randomly allotted to a 9 x 8 Youden square with 9 diets and eight 7-d periods. Meat proteins (Table 1) were included in the diet as the only source of AA. The DIAAS for each meat protein was calculated using the Food and Agriculture Organization of the United Nations (FAO) established reference patterns for children 6 mo to 3 yr and older children, adolescents, and adults. Data were analyzed using PROC MIXED of SAS in a randomized complete block design with the pig as the experimental unit. In Exp. 1, all meat proteins had a DIAAS greater than 100% regardless of the reference pattern. For both reference patterns, the DIAAS for smoked-cooked bacon was greater (P < 0.05) than for raw belly and smoked bacon, the 2 cured hams had a numerically greater DIAAS than the uncured ham, and the medium loin had a greater (P < 0.05) DIAAS compared with the medium-well and well-done loins. In Exp. 2, most proteins had a DIAAS value greater than 100%. For both reference patterns, raw ground beef had a greater (P < 0.05) DIAAS than cooked ground beef, and medium ribeye roast had a greater (P < 0.05) DIAAS than medium-rare and well-done ribeye roasts. In conclusion, curing and moderate cooking may increase DIAAS, whereas grinding meat prior to some, but not all, cooking methods or overcooking may reduce the DIAAS of meat proteins.
