Resumo

Most of the probiotic food products are milk-based, but factors like vegetarian habits or intolerance to dairy products has encouraged the use of non-dairy raw materials or ingredients with low lactose content for the development of food products. Whey protein isolate, which has less than 0.5% lactose, and water extract of soybean (soymilk) may be alternatives for lactose intolerant individuals. Therefore, the effect of replacing milk (M) by soymilk (S) and/or whey protein isolate + inulin (PI) on the probiotic and pH of apple ice-creams throughout 84 days of storage at -18 °C was investigated. Employing a simplex-centroid mixture design, seven ice-cream-making trials were produced and supplemented with the probiotic microorganisms Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12, and the prebiotic ingredient oligofructose: T1 – M; T2 – S; T3 – PI; T4 – M + S; T5 – M + PI; T6 – S + PI; and T7 – M + S + PI. The final products were stored at-18°C up to 84 days and on each sampling day (days 1, 7, 28, 42 and 84) the viability of probiotic cultures and pH values were monitored. In general, the replacement of milk by soymilk and/or whey protein isolate + inulin resulted in products with significant lower pH (p<0.05). All products showed satisfactory La-5 and Bb-12 populations during the whole storage period, remaining always above 7.0 log cfug-1. However, comparing T2-T7 with T1, the viability was lower in T6 and T7 for La-5, and in T3 and T6 for Bb-12 (p<0.05), suggesting that the presence of S+PI (T6 and T7), and PI or S+PI (T3 and T6) led to a decrease in the probiotic viability. Even though certain variations in La-5 and Bb-12 populations were observed, the replacement of milk by soymilk and/or whey protein plus inulin did not negatively affect the probiotic viability of apple ice-creams throughout the storage period evaluated, since these formulations proved to be good vehicles for La-5 and Bb-12 strains, with appropriate populations to characterize them as probiotic products. The partial or total replacement of milk with other ingredients may expand the range of probiotic and synbiotic products options for individuals, particularly for those with varying degrees of lactose intolerance.