RESUMO

The objective of this study was to investigate the impacts of high-intensity ultrasound treatments on the compositional, physicochemical, biochemical, functional and structural properties of canola protein isolates (CPI). Aqueous canola protein suspensions were sonicated at 40 kHz for 15 min and 30 min. The moisture content, water activity, bulk density and the L* and a* color parameters of the CPI decreased due to the ultrasound; however, the in vitro protein digestibility was not modified by the treatment. Glutelin (57.18%) was the main protein fraction in the canola protein isolate. SDS-PAGE demonstrated that there were no changes in the protein electrophoretic patterns, thus indicating that sonication did not break the covalent bonds. However, the ultrasound treatment improved the protein solubility, oil absorption capacity and the emulsifying, gelation and foaming properties, but these improvements depended on the pH and ultrasound exposure time. Scanning electron microscopy revealed that the ultrasound treatment disrupted the microstructure of the CPI by exhibiting larger aggregates as a lyophilized powder. In addition, there was an increase in the surface hydrophobicity and a decrease in the size of the particles of the canola protein due to the ultrasound effects, which indicates a destruction of the particles or a dissociation of the protein aggregates in the canola protein dispersions. These results suggest that ultrasound treatment is a valuable tool for improving the characteristics of canola proteins for use in foods.

Assuntos

Brassica napus/química , Fenômenos Químicos , Proteínas de Plantas/isolamento & purificação , Ondas Ultrassônicas , Cor , Eletroforese em Gel de Poliacrilamida , Emulsões , Tecnologia de Alimentos , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Peso Molecular , Tamanho da Partícula , Proteínas de Plantas/metabolismo , Solubilidade , Sonicação , Água/análise

RESUMO

The aim of the present study was to produce fish silage by lactic acid fermentation and evaluate its use in feeding of quails (Coturnix coturnix japonica). An oven-dried mixture of fish silage and soybean meal (1:1 w/w) was used to prepare the diets with different levels of inclusion (0, 10, 20 and 30%) and evaluate its effect on the performance and meat quality of 160 quails. The inclusion level did not affect the growth and feed conversion ratio. The carcass yield (70.3%) and sensory quality of breast meat were not significantly different among the treatments (p>0.05). However, the concentration of unsaturated fatty acids such as oleic (C18:1n9C), linoleic (C18:2n6C), linolenic (C18:3n3), arachidonic (C20:4n6), cis eicosapentaenoic (C20:5n3) and cis docosahexaenoic (C22:6n3) increased in quail breast meat with the inclusion of fish silage:soybean mixture in the diet (p<0.05). Fish silage and its use in quail diets could offer a good alternative for fish waste utilization as feedstuff component for the improvement of fatty acid composition in its breast meat.