In the lactic acid bacteria (LAB) strains screened from our LAB collection, Lactobacillus (L.) sakei strain no. 23 and L. curvatus strain no. 28 degraded meat protein and tolerated salt and nitrite in vitro. Fermented sausages inoculated strains no. 23 and no. 28 showed not only favorable increases in viable LAB counts and reduced pH, but also the degradation of meat protein. The sausages fermented with these strains showed significantly higher antioxidant activity than those without LAB or fermented by each LAB type strain. Angiotensin-I-converting-enzyme (ACE) inhibitory activity was also significantly higher in the sausages fermented with strain no. 23 than in those fermented with the type strain. Higher ACE inhibitory activity was also observed in the sausages fermented with strain no. 28, but did not differ significantly from those with the type strain. An analysis of the proteolysis and degradation products formed by each LAB in sausages suggested that those bioactivities yielded fermentation products such as peptides. Therefore, LAB starters that can adequately ferment meat, such as strains no. 23 and no. 28, should contribute to the production of bioactive compounds in meat products.
Forty-eight 154-d-old White Leghorn hens were fed a diet containing 0 (control), 0.5, 1.0 and 1.5% bamboo charcoal powder including vinegar liquid (SB). Compared with the control group, production performance in the SB groups did not differ. Egg production tended to be increased in the 0.5 and 1.0% SB groups, but decreased in the 1.5% SB group; the former two groups were higher than the latter (P<0.05). The SB groups showed a lower level of faecal ammonia gas and a higher level of polyphenol in the egg yolk, but the differences were not statistically significant. The intestinal villus height, cell area, and cell mitosis number tended to be higher in the SB groups. Duodenal cell mitosis was increased in all SB groups (P<0.05). The control group showed flat cells on the villus apical surface, while the SB groups showed protuberated cells. The present results indicate stimulating effects of dietary SB on intestinal villi and structure of epithelial cells and the 0.5 and 1.0% levels improved production performance. These suggest that the SB can be supplemented until a level of 1.0%.
We investigated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition and lipid oxidation in breast meat of broiler chickens. Broiler chickens (28-day-old females) were fed diets containing experimental oils at 20 g/kg diet for 28 days. The experimental oils consisted of either a 2:0, 1:1, or a 0:2 (wt : wt) ratio of safflower oil (high linoleic acid content) to a commercial CLA mixture. In this study, dietary CLA supplementation significantly increased the composition and content of CLA in chicken meat. The predominant CLA in meat from birds with supplemented diets was the cis-9, trans-11 isomer. The proportion of saturated fatty acid in meat significantly increased with increasing CLA supplementation, with a corresponding decrease in monounsaturated fatty acid. Dietary CLA also reduced thiobarbituric acid reactive substances (TBARS) values in raw meat during storage at 4 degrees C for 5 days. These results provide evidence that CLA feeding is a practical strategy not only for adding nutritional benefits to chicken meat but also for improving meat quality including oxidative stability.
We studied the gel properties of porcine collagen with microbial transglutaminase (MTGase) as a catalyst. A creep meter was used to measure the mechanical properties of gel. The results showed samples with high concentration of MTGase gelled faster than those with a low concentration of MTGase. The gel strength increased with incubation time and the peaks of breaking strength for 0.1, 0.2 and 0.5% MTGase were obtained at 40, 20 and 10 min incubation time, respectively. According to SDS-PAGE, the MTGase was successfully created a collagen polymer with an increase in molecular weight, whereas no change in formation was shown without MTGase. The sample with 0.5% MTGase began to polymerize after 10 or 20 min incubation at 50°C, and complete polymerization occurred after 40-60 min incubation. Scanning electron microscopic analysis revealed that the gel of porcine collagen in the presence of MTGase produced an extremely well cross-linked network. The differential scanning calorimetric analysis showed the peak thermal transition of porcine collagen gel was at 36°C, and that with MTGase no peak was detected during heating from 20 to 120°C. The melting point of porcine collagen gel could be controlled by MTGase concentration, incubation temperature and protein concentration. Knowledge of the structural and physicochemical properties of porcine collagen gel catalyzed with MTGase could facilitate their use in food products.
The five most widely accepted procedures for preparing fatty acid methyl esters in food lipids were investigated for their suitability in capillary gas-liquid chromatographic analysis of cis-9, trans-11 conjugated linoleic acid (c-9, t-11 CLA) in meat. A modified procedure of fatty acid methyl esterification was developed and the method was applied to determine c-9, t-11 CLA content in some resulting c-9, t-11 CLA methyl ester was separated by gas-liquid chromatograph equipped with a capillary column and determined using tricosanoic acid as an internal standard.Meat from ruminant animals considerably contained more c-9, t-11 CLA than those from non-ruminant animals in the following order: goat meat, beef, mutton, pork, and chicken.The amount in goat meat (6.35mg/g lipid) was 10-fold greater than those in pork and chicken.
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