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This study was designed to provide updated information on the separable components, cooking yields, and proximate composition of retail cuts from the beef chuck. Additionally, the impact the United States Department of Agriculture (USDA) Quality and Yield Grade may have on such factors was investigated. Ultimately, these data will be used in the USDA - Nutrient Data Laboratory's (NDL) National Nutrient Database for Standard Reference (SR). To represent the current United States beef supply, seventy-two carcasses were selected from six regions of the country based on USDA Yield Grade, USDA Quality Grade, gender, and genetic type. Whole beef chuck primals from selected carcasses were shipped to three university laboratories for subsequent retail cut fabrication, raw and cooked cut dissection, and proximate analyses. The incorporation of these data into the SR will improve dietary education, product labeling, and other applications both domestically and abroad, thus emphasizing the importance of accurate and relevant beef nutrient data.

Recommendations to increase dietary intakes of starch and fiber in the United States may result in increased intake of resistant starch. High-amylose starch appears to resist digestion in vitro. To investigate the in vivo effect of high-amylose starch, diets containing 70% amylose or amylopectin cornstarches were fed for 14 wk each in a crossover design to 24 men [10 control, 14 hyperinsulinemic (HI)]. Fasting breath samples and periodic postingestion samples were analyzed for hydrogen during weeks 12 (nibbling tolerance test) and 14 (acute tolerance test) of each phase. Overall breath hydrogen was significantly higher after the amylose tolerance tests (nibbling, P0.0005; and acute, P0.0006). Control subjects, regardless of body mass index (BMI; in kg/m2), appeared to adapt to the high-amylose starch diet. Fasting breath hydrogen was significantly higher at week 12 but not at week 14 in HI subjects with a low BMI (25) consuming amylose than in other subjects. Breath hydrogen of the HI subjects with a moderate (between 25 and 27.8) or high (27.8) BMI increased from week 12 to week 14. The HI subjects with a high BMI averaged lower breath-hydrogen expiration than other HI subjects. After 3 d of excess energy intake, breath hydrogen after amylose was still significantly greater than after amylopectin (P0.019); fasting breath hydrogen of the control subjects after amylose more closely resembled that of the HI subjects. HI subjects with a high BMI may be more efficient at digesting all starch, therefore decreasing the amount available for colonic digestion. This may be a factor contributing to their greater body weight.

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Long-term consumption of high-amylose starch on insulin and glucose response was investigated in 24 men: 10 control and 14 hyperinsulinemic (HI) subjects. Subjects consumed products made with standard (70% amylopectin, 30% amylose) or high-amylose (70% amylose, 30% amylopectin) cornstarch for two 14-wk periods in a crossover pattern. Starch products replaced usual starches in the self-selected diet for 10 wk followed by 4 wk of a controlled diet. After a starch-tolerance test with bread made from the starch consumed during that period, the insulin response curve area was significantly lower in all subjects after amylose consumption (P < 0.002). Glucose responses in HI and control subjects were similar and did not vary with the type of starch. Fasting triglyceride concentrations were significantly lower in subjects who consumed the high-amylose compared with the standard-starch diet throughout the study. Chronic consumption of high-amylose foods normalized the insulin response of hyperinsulinemic subjects and showed a potential benefit for diabetic subjects.

Recommendations made to increase complex carbohydrate and fiber intake in the United States may result in energy loss from increased fecal losses of starch, protein, and fat. The type of fiber or starch and the amount consumed affect digestion of the carbohydrate and interactions with other nutrients. On average, 8.4 kJ (2 kcal) digestible energy/g is available from up to 70 g poorly digested carbohydrate/d. Undigested fiber and starch are important substrates for colon bacteria and are fermented to short-chain fatty acids, hydrogen, and methane. Hydrogen and methane excreted through the lungs have been used as indicators of colonic fermentation. Fermentation appears to contribute significant digestible energy when > 20 g poorly digested carbohydrate/d is consumed.