Ultrasound-assisted enzymatic hydrolysis of goat milk casein: Effects on hydrolysis kinetics and on the solubility and antioxidant activity of hydrolysates.

This study evaluated the ability of ultrasound (US) bath to improve the hydrolysis of goat milk casein (GMC) by three commercial proteases (Alcalase, Brauzyn and Flavourzyme) using assisted reactions at 60 °C for up to 300 min. Process performance was evaluated based on the rate reaction, final hydrolysis degree, solubility, and antioxidant activity of the hydrolysates. For all enzymes, the US-assisted reaction increased the rate of GMC hydrolysis (up to 120%), the hydrolysis degree (23-48%), and the small peptides formed, i.e., those soluble in trichloroacetic acid (TCA) (up to 40%). Consequently, US-assisted GMC hydrolysis improved the solubility of the hydrolyzed product (up to a 35.7% increase after 300 min of reaction) and, compared to conventional hydrolysis, reduced the time to achieve the maximum solubility by up to 10 times. Regarding the in vitro antioxidant activity, especially for Alcalase, the technology promoted a higher scavenging capacity of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (p < 0.05), thus 10-fold accelerating the production of antioxidant peptides, according to ABTS assays (p < 0.05). In conclusion, the US-assisted enzymatic reaction is a promising technology to improve the hydrolysis rate and yield of the process of obtaining hydrolysates from GMC. Moreover, these hydrolysates showed high solubility and good in vitro antioxidant activity, which demonstrates the potential to be used as food ingredient with nutritional and techno-functional appeal.

Avaliação sensorial e microbiológica de bebida mista de vegetais adicionada de probiótico / Sensory and microbiological evaluation of mixed vegetable drinks with probiotic

Bebidas de origem vegetal vêm sendo estudadas como carreadoras de bactérias probióticas. Neste estudo objetivou-se elaborar duas bebidas mistas probióticas sabor goiaba e beterraba: BMAP (bebida mista à base de extrato de amendoim) e BMSP (à base de extrato de soja), que foram adicionadas de Lactobacillus rhamnosus GG. Avaliaram-se características sensoriais e microbiológicas das bebidas elaboradas e de uma bebida comercial a base de soja disponível no mercado (BSC). Verificou-se que, após o processamento, as bebidas BMAP, BMSP e a BSC apresentaram escores equivalentes a "gostei ligeiramente" e "gostei muito" para os atributos acidez, cor, sabor, aroma, textura e impressão global, e escores equivalentes a "talvez comprasse, talvez não comprasse" e "provavelmente compraria" na avaliação de intenção de compra, não havendo diferença das bebidas elaboradas para a comercial. Verificaram-se contagens de LGG superiores a 6,8 Log UFC. mL-1 nas bebidas. Todas as amostras estavam de acordo com os padrões microbiológicos exigidos pela legislação brasileira. As bebidas apresentam potencial de mercado e são consideradas um excelente veículo de LGG, além de uma nova opção de bebida funcional, não láctea, acessível à população.(AU)

Vegetable beverages have been studied as carriers of probiotic bacteria. The objective of this study was to elaborate two probiotic mixed beverages from guava and beet: BMAP (mixed beverage based on peanut extract) and BMSP (based on soy extract), which were added of Lactobacillus rhamnosus GG. Beverages from both matrices, without addition of probiotic, were denominated control (BMAC and BMSC). Sensory and microbiological characteristics of the elaborated beverages and a commercially available commercial soybean drink (BSC) were evaluated. It was verified that, after the processing, the BMAP, BMSP and BSC beverages presented "slightly liked" and "liked" scores for the attributes of acidity, color, flavor, aroma, texture and overall impression, and " maybe buy, maybe not buy "and" would probably buy "in the evaluation of the intention to buy, there being no difference of the beverages from to the commercial. LGG counts were above 6.8 Log UFC.mL-1 in the beverages. All samples were in accordance with the microbiological standards required by Brazilian legislation. The beverages present market potential and are considered a excellent vehicle of LGG and a new functional beverage option, not dairy, accessible to the population.

Vida de prateleira de alface americana tratada com água ozonizada / Shelf life evaluation of the iceberg lettuce sanitized with ozone water

RESUMO:Este trabalho avaliou se a higienização de alface americana com água ozonizada, na concentração de 1,0mg L-1 por 1, 2 ou 3 minutos, seria capaz de aumentar a vida útil do produto quando armazenado a 2ºC. Foram avaliadas as populações de microrganismos aeróbios mesófilos, Enterobacteriaceae, bolores e leveduras, coliformes totais, coliformes termotolerantes e pesquisa de Salmonellasp ao longo do tempo. Imediatamente após o processamento por 3 minutos, foram obtidas reduções decimais de 4,07; 3,36; 3,20; 2,18 e 2,18 de microrganismos aeróbios mesófilos,Enterobacteriaceae, bolores e leveduras, coliformes totais, coliformes termotolerantes, respectivamente. A presença de Salmonellasp. não foi observada em nenhuma das condições estudadas. Além do efeito na inativação inicial, o processamento com ozônio melhorou a estabilidade da alface durante a estocagem, aumentando o tempo para o início do crescimento microbiano (de zero para quatro dias) e reduzindo a taxa de crescimento dos microrganismos, especialmente quando a sanitização foi realizada por 3 minutos de contato. Os resultados demonstraram que a alface tratada com água ozonizada atendeu aos parâmetros da legislação durante o período avaliado, reduzindo a contaminação inicial das alfaces (que, sem tratamento, estavam microbiologicamente impróprias para consumo pela contagem de coliformes) e mantendo essas contaminações em níveis aceitáveis por até 10 dias, sob refrigeração.

ABSTRACT:This research studied the impact of Iceberg lettuce sanitation using ozonized water at 1.0mg L-1 for 1, 2 and 3 minutes in the vegetable shelf-life at 2ºC. It was evaluated populations of aerobic mesophilic bacteria, EnterobacterIaceae, molds/yeasts, total and thermtolerants coliforms, andSalmonellasp. Immediately after 3 minutes of sanitation, decimal reductions of 4.07 (aerobic mesophilic bacteria), 3.36 (EnterobacterIacea), 3.2 (molds/yeasts), 2.18 (total coliforms) and 2.18 (thermtolerants coliforms) were reached. Salmonellasp. was not founded at any evaluated condition. Additionally to the initial reduction, the ozonization improved the lettuce stability during its shelf-life, increasing the delay for microbial growth (from zero to four days) and reducing the microbial growth rate. It occurred especially when sanitation with ozone was carried for 3 minutes of contact. The results showed that the Iceberg lettuce sanitized with ozonated water meets the Brazilian law during the evaluated period, reducing lettuce initial load (that was initially unsafe due to high count of coliforms) and keeping this contamination acceptable for 10 days under refrigeration.