ABSTRACT
Abstract This study was aimed at optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from jussara and blueberry fruits using the response surface methodology (RSM). UAE was found to be more efficient to extract phenolic compounds from both fruits than the conventional extraction. The optimum extraction conditions for the jussara fruits were: extraction time between 30 and 62 min for total anthocyanins and total phenolics, fruit:solvent ratio of 10% and 6% (w/v) for total anthocyanins and total phenolics, respectively. The ethanol concentration was non-significant (p> 0.05). Acidified water was found to be an extracting solvent as efficient as ethanol in the extraction of phenolic compounds from jussara fruits. The optimum extraction conditions for blueberry anthocyanins were: ethanol concentration between 20-70% vol, and fruit: solvent ratio greater than 20% (w/v) within the range studied. The extraction time was not significant (p> 0.05). For total phenolic content: the concentration of ethanol was between 40-80%, and fruit: solvent ratio greater than 20% (w/v) and extraction time over 50 minutes. It was possible to adjust the mathematical model for the coordinates a* (verde vs vermelho) and C* (color saturation) of the jussara extracts.
ABSTRACT
A indústria de leite e derivados no Brasil lança todos os anos diversos novos produtos no mercado, incluindo produtos de alto valor nutricional e tecnologia de fabricação de baixo custo. Focando neste tema, foi avaliado o efeito do envase a quente de uma bebida a base de soro de leite tratada termicamente após fermentação, e sua conservação à temperatura ambiente, por 84 dias. Durante o processamento, utilizou-se um tratamento térmico brando, aliado ao baixo pH, para que a bebida pudesse ser armazenada a temperatura ambiente. Garrafas PET de 250 mL foram utilizadas para o envase a quente do produto. Para avaliar sua estabilidade durante o armazenamento, foram realizadas periodicamente análises físico-químicas, microbiológicas e análise sensorial. Os resultados obtidos foram analisados por análise de variância e teste de Tukey para comparação de médias. Análises físico-químicas e microbiológicas indicaram que a bebida manteve-se estável; entretanto, o sabor foi alterado ao longo do armazenamento. O baixo custo do processamento e embalagem são benefícios do produto avaliado, podendo-se concluir que a bebida é uma boa forma para a utilização do soro de leite. Uma grande vantagem deste produto é o seu armazenamento à temperatura ambiente, dispensando o uso da refrigeração durante o transporte e acondicionamento em supermercados.
The Brazilian dairy industry launches several new products on the market every year, including products with high nutritional value and low-cost manufacturing technology. Focusing on this issue, a cheese whey beverage thermally treated after fermentation was hot-filled and evaluated for 84 days. During the beverage manufacturing, we applied a mild heat treatment in combination with low pH aiming to store the beverage at room temperature. PET bottles were used to hot filling of the product. To assess the product stability during the storage period, we performed, periodically, physico-chemical, microbiological and sensory analysis. The obtained results were analyzed by the Analysis of Variance and Tukey's test. Physical-chemical and microbiological analysis indicated that the beverage remained stable; however, the flavor was altered during the storage period. Since hot-filling of dairy beverages in PET bottles is a low cost-effective procedure easily deployed in dairy plants, this process allows the productive use of cheese whey. A remarkable advantage of such product is its possible storage at room temperature, reducing distribution and sales expenditures with cooling.