Fermented milk beverage: formulation and process

ABSTRACT: Dairy products are an adequate alternative as functional foods since they present excellent nutritional value, have wide acceptance with consumers, and are potential matrices for inoculation of probiotic microorganisms. The present study aimed to develop a fermented milk beverage with fruits and a probiotic culture included, to evaluate the acceptance of this product among consumers to define the ideal formulation, and to perform Lactobacillus acidophilus counting in order to characterize the product as a probiotic food. For the formulation of the beverage, milk, whey, sugar, and pasteurized orange and papaya pulps were used as main ingredients. The beverage formulation consisted of mixing the fruit pulps with a dairy substrate of milk and whey which was previously fermented using a mixed commercial probiotic ABT-5 culture. Six formulations were tested. The milk substrate was maintained at 70%. These formulations consisted of 50% of mineral water and 50% of skimmed milk with a concentration of probiotics of 0.5g/L. Sugar concentration varied between 40g, 70g, or 100g. As for flavoring, the juice was composed of 180mL of papaya and 120mL of orange, or 150mL of papaya and 150mL of orange. Beverages were prepared and then stored at 5±1°C. These products were evaluated after 24 hours of preparation/storage by 90 tasters (consumers) for acceptance and sensory characterization. Data were analyzed by ANOVA. The differences between samples were evaluated using the Tukey test at a significance level of 5%. Acceptance of the beverage samples among tasters varied from 5.1 to 6.9 and ranged between the hedonistic terms I neither liked nor disliked it and somewhat enjoyed it in a 9-point hedonic scale. The enumeration of Lactobacillus acidophilus LA-5 ranged from 7.83 to 8.09log CFU/mL in the first week of refrigerated storage. Our results suggested that the beverages analyzed were suitable for inoculation of probiotics and met the legislation requirements. Therefore, these beverages should be classified as probiotic products. Samples with 10% sugar were the least preferred by the study participants whereas beverages containing 40g, 70g and 180mL of papaya juice and 120mL of orange juice and the sample with 70g of sugar, 150mL of papaya juice, and 150mL of orange juice did not differ significantly from each other in terms of acceptance and were; therefore, the 3 formulations that received the highest means of acceptance by consumers.