Anais do Simpósio Latino Americano de Ciências de Alimentos
Actas del 14 SLACA - Simposio Latinoamericano de Ciencia de los Alimentos

Several consumers have been looking for products rich in protein, reduced in sugar and fat, and lactose-free, stimulating the development of dairy products. However, the development of yogurts with defined amounts of whey(W), co-product of the cheese industry, and different types of whey protein concentrate (WPC), a high biological value protein, such as isolate (WPI) or hydrolyze (WPH), needs to be investigated. Therefore this research aims to produce four formulations of yogurts with mixture in a fixed proportion 35%W-65%skim milk (M) enriched or not with 3%protein (m/v) of WPC, WPI or WPH (M, M+WPC, M+WPI, M+WPH), and analyze physicochemical characteristics during storage (1, 7, 14, 21 and 28 days). Samples were heated(80°C/20min) and, after cooling, (43°C) were added with lactic culture(0.2U/L) and lactase(30U/g lactose). M+WPH flocculated after heating, possibly facilitated by denaturation of the smaller proteins chains. Fermentation kinetics was evaluated until pH 4.7, and in protein enriched samples fermentation time increasing from 3.5 to 4.0h and higher dry extract was reached (p<0.05). During storage, the pH varied from 4.5 to 4.7 for all samples, and acidity was lower than allowed by legislation for M. The water holding capacity (WHC) showed an increase of 184% in M+WPC and 255% in M+WPI (p<0,05) because of the power WHC of whey proteins. M+WPC viscosity after 7 days (50-60mPa.s) was 3x higher than M (p<0.05), both ideal for whipped yogurt, while M+WPI showed up to 3500mPa.s, ideal for traditional yogurt. Differences between M+WPC and M+WPI may be due to conformation modifications of proteins generated in the microfiltration process to obtain WPI from WPC. Therefore, the addition of WPC or WPI contributed to the characteristics and became attractive for the dairy industry, fitting to the next steps the study of other proportions of M, WPC, and WPI that will be used in sensory studies.