Objective
The influence of broiler carcass scalding conditions on chicken breast meat quality parameters was investigated.
Methods
Two hundred and seventy Cobb broiler chickens from 42 to 48 days old were slaughtered according to the standard industry practice and scalded in five temperature/time combinations—T
1
, 54°C/210 s; T
2
, 55°C/180 s; T
3
, 56°C/150 s; T
4
, 57°C/120 s; T
5
, 58°C/90 s.
Results
Scalding temperature increase resulted in higher values of external and ventral lightness and in protein functionality reduction—determined by emulsification capacity and protein denaturation—in chicken breast fillets 24 h
post-mortem
. Protein secondary structures had conformational changes, with a decrease of the α-helix and an increase of the β-sheet and β-turn proportions, mainly in T
1
and T
5
samples, determined by Fourier-transform infrared spectroscopy in an attenuated reflectance mode analysis. The chemical composition, pH, water holding capacity and Warner-Bratzler shear force did not differ among the treatments. In the fatty acid profile, the 18:1n-9 was lower in T
5
, which suggested that the high scalding-temperature could have caused the lipid oxidation. The values of the polyunsaturated fatty acids (PUFA), such as 22:2, 20:4n-6, and 22:6n-3, were highest in the T
5
, thus being related to the phospholipid cellular membrane collapse in this experimental condition and subsequent release of these PUFA.
Conclusion
Intermediate scalding-parameters avoided the negative changes in the chicken meat quality.
The influence of stunning methods on the physicochemical and biochemical parameters of chicken breast meat, as indicators of bird stress, was investigated. A total of 200 Cobb broiler chickens aged from 42 to 48 d were submitted to gas or electrical stunning and slaughtered according to the standard industry practice. Pectoralis major muscles (24 h post-mortem) from broilers stunned by electronarcosis exhibited a higher L* and R-value and lower pH45min than did those from gas stunning, indicating modification of the glycolytic rate. Protease activity, measured as the myofibril fragmentation index, and the sarcoplasmic Ca2+ concentration were highest in samples from broilers stunned by electronarcosis, suggesting the greatest activity of the calpain system. In the fatty acid profile, a higher ratio of polyunsaturated fatty acids was observed in samples from broilers stunned by electronarcosis. These characteristics are related to phospholipase A2 activity, which is higher in animal stress conditions. These results indicated that the gas-stunning method produced less bird stress than electrical stunning.
Biodiesel susceptibility to oxidation is one of the major problems concerning its use as an alternative to diesel fuel. Although well-characterized, the oxidation process cannot be completely prevented since it can be affected by a large number of factors, such as fuel composition, storage conditions, contaminants, temperature, and the presence of air and light. In this work, we propose Fourier transform infrared spectroscopy (FTIR) in association with principal components analysis (PCA) and hierarchical cluster analysis (HCA) as a method for monitoring the extent of oxidation degree of biodiesel in the low rate phase, before the end of the induction period, in which the changes in the physical properties such as viscosity, mass density, and chain composition of the sample remain almost undetectable. A detailed investigation of thermo-oxidation of biodiesel is reported for a mixture of 50/50 (%) of soybean oil and animal fat biodiesels. The biodiesel degradation was accelerated when maintaining the temperature of the sample at 110 °C under constant air flux for different times. Oil stability index, mass density, viscosity, gross caloric value, esters composition, UV−vis, and FTIR spectra were measured in order to analyze the degree of degradation of each sample. The multivariate analysis in the FTIR spectra clearly shows the discrimination of the samples in the first stage of the degradation process. These results could be useful as a method for monitoring the fuel quality during storage, helping fuel producers, suppliers, and users.
The aim of this study was to produce cereal bars (CB) added with tempeh flour (TF) and evaluate the nutritional composition, fatty acids profile, isoflavones content, and sensory acceptance. Tempeh was produced from organic soybeans cotyledons fermented by Rhizophus oligosporus followed by freezedrying and milling in order to obtain the TF. The addition of 0% (control), 10%, 15%, and 20% TF to CB resulted in both protein and lipid content increase and a higher polyunsaturated/saturated fatty acids ratio. The content of isoflavone aglycones, the forms considered to have higher biological activity, was higher in TF than in soybean, which was also reflected in the CB chemical composition. An acceptance test showed that CB added with TF (up to 15%) were sensory accepted. Overall results suggest that the addition of TF as an ingredient in cereal bars allows improving the chemical and functional characteristics of this type of ready-to-eat foods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.