RESUMO
Yellow corn cooking water with yerba mate (Ilex paraguariensis) extract, obtained as a by-product of snack manufacture, was combined with whey protein concentrate (7 g/100 g), flaxseed (Linum usitatissimum L.) flour (2 g/100 g), and honey (8 g/100 g) to obtain different gelled products. The effect of the composition on the physicochemical parameters was analyzed. Flaxseed flour was added directly or with a previous pre-heating, and, in both cases, it increased the solid behavior of gels. On the contrary, honey increased the gel liquid-like behavior, and both ingredients modified the color of the gels. Elastic and loss modulus decreased after storage for 7 and 14 days. Some of the textural parameters also changed during storage. Principal component analysis and cluster analysis revealed three groups of formulations according to their composition, and those samples containing only flaxseed flour were best described with the textural and rheological parameters. Yerba mate extract, mainly, flaxseed flour, and honey increased the phenolic composition of gels but decreased the sensory acceptability, despite the sweetness of honey. A variety of gelled products with different textures and flavors was obtained using by-products of the food industry. These gels could be used either for dessert formulations or as a matrix for gelled products.
RESUMO
ABSTRACT In this research, the effect of the lactic starter culture, the fermentation time, the incubation temperature and the percentage of fat on the firmness and consistency of a fermented milk drink was evaluated through physicochemical characteristics of total acidity, pH, syneresis and flow behavior. The purpose was to find the best formulation that extends the shelf life of yogurt, leading to an improvement in the manufacturing process of a local dairy company in Barrancabermeja (Santander, Colombia). Quality criteria were evaluated by means of the percentage of acidity and pH of the yogurt, as well as its syneresis and rheological parameters during a storage time of 24 hours and 7 days in refrigeration. Acceptable quality parameters were obtained for the yogurt prepared with an inoculum concentration of 2%, an incubation temperature of 40°C and an incubation time of 150 minutes. In addition, better properties of firmness and consistency were found, with absence of syneresis and viscosity in the accepted range, for this dairy product.
RESUMEN En esta investigación, se evaluó el efecto del cultivo iniciador láctico, el tiempo de fermentación, la temperatura de incubación y el porcentaje de grasa en la firmeza y consistencia de una bebida de leche fermentada, a través de las características fisicoquímicas de acidez total, pH, sinéresis y comportamiento de flujo. El propósito fue encontrar la mejor formulación que extienda la vida útil del yogur, lo que lleva a un perfeccionamiento del proceso de fabricación de una empresa local de productos lácteos en Barrancabermeja (Santander, Colombia). Se evaluaron criterios de calidad por medio del porcentaje de acidez y pH del yogurt, así como su sinéresis y parámetros reológicos, durante un tiempo de almacenamiento de 24 horas y de 7 días en refrigeración. Se obtuvieron parámetros de calidad aceptables para el yogurt, preparado con una concentración del inóculo de 2%, una temperatura de incubación de 40°C y un tiempo de incubación de 150 minutos. Además, se encontraron mejores propiedades de firmeza y de consistencia, con ausencia de sinéresis y viscosidad en el rango aceptado, para este producto lácteo.