The influence of different combinations of probiotic bacteria and fermentation temperatures on the microbiological and physicochemical characteristics of fermented lactic beverages containing soybean hydrosoluble extract during refrigerated storage

Abstract

Lactic beverages containing probiotics were prepared with whole UHT milk, whey of Mozzarella cheese, soybean hydrosoluble extract and sugar. Three formulations were studied, each one containing a different combination of probiotic/starter bacteria, fermented at two different temperatures (37 and 45 °C). The aim of this work was to verify the influence of these variables on the viability of probiotic microorganisms and on the physicochemical stability of lactic beverages during storage under refrigeration (21 days at 7 °C). The results indicated that the fermentation temperature had a significant effect on the viability of probiotic bacteria. Counts for Lactobacillus acidophilus were affected by storage time, resulting appropriate after 21 days only for the beverage fermented at 37 °C. Physicochemical parameters did not exhibit drastic variations -proving the stability of formulations during storage. Cells of Bifidobacterium spp. showed high survival ability, probably due to the presence of growth promoters from soybean and cheese whey. The fermentation temperature of 37 °C allowed counts above the minimum limit for all the studied microorganisms, being preferred to the temperature of 45 °C. The inclusion of soybean hydrosoluble extract, a prebiotics source, resulted in a symbiotic product with more benefits to the health of consumers.

Fermented beverage based on water-soluble soybean extract

“…According to FUCHS et al (2005), the typical pH and acidity characteristics of fermented milk are ideal parameters for gel formation due to protein coagulation. Other authors have reported similar data for yogurts produced with mixtures of cow's milk and soy products (CAMARGO et al, 2000;FIORENTINI et al, 2011;FUCHS et al, 2005). Although the present fermented beverage cannot be characterized as a yogurt since it does not present sufficient milk proteins for such designation (BRAZIL, 2000;BRAZIL, 2007), the usual designation for WSSE-based products is commonly 'soy yogurt' or 'soy milk beverage' (BREN, SANTOS, ALMEIDA, 2010;FIORENTINI et al, 2011;MANZANO et al, 2008;MORAES et al, 2006).…”

“…Other authors have reported similar data for yogurts produced with mixtures of cow's milk and soy products (CAMARGO et al, 2000;FIORENTINI et al, 2011;FUCHS et al, 2005). Although the present fermented beverage cannot be characterized as a yogurt since it does not present sufficient milk proteins for such designation (BRAZIL, 2000;BRAZIL, 2007), the usual designation for WSSE-based products is commonly 'soy yogurt' or 'soy milk beverage' (BREN, SANTOS, ALMEIDA, 2010;FIORENTINI et al, 2011;MANZANO et al, 2008;MORAES et al, 2006). The pH values observed in this study conferred product safety, since the most common pathogens in foods are inhibited at pH values below 4.5 owing to the presence of organic acids, which is characteristic of the metabolism of LAB.…”

“…Regarding the sensory evaluation, the acceptance test showed mean scores of >6.0 on a 1-9 scale for all attributes evaluated (Table 2), indicating a good acceptance of the product. In addition, the fermentation process can improve not only the sensory aspects but also the nutritional value of the final product, resulting in the development of suitable flavours and aromas (CAMARGO et al, 2000;FIORENTINI et al, 2011;MORAES et al, 2006). Moreover, the process also improves the bioactive compounds and decreases the anti-nutritional factors, which may contribute to the increased acceptance and positive effects of fermented soybean products (BREN, SANTOS, ALMEIDA, 2010;VAGADIA, et al;2018;WATANABE et al, 2017).…”

Probiotics Consumption Increment through the Use of Whey- Based Fermented Beverages

“…In another study, Fiorentini et al [37] evaluated the influence of different combinations of probiotic bacteria and different fermentation temperatures on the physico-chemical characteristics of fermented lactic beverages based on soybean and whey. For this purpose, a lyophilized probiotic culture was used, composed of L. acidophilus and Bifidobacterium (B) bifidum.…”

“…In this order of ideas, Fiorentini et al [37] performed a viable lactic bacteria count in fermented beverages prepared from whey and soybean addition, after 7, 14, and 21 days storage under refrigeration at 7 C. They performed a selective count of L. acidophilus on modified MRS agar, with aerobic incubation and a count of B. bifidum on MRS agar modified with anaerobic incubation, both at 37 C for 72 h, finding that the number of alive micro-organisms in the fermented drink was 10 7 UFC/ml. Londoño et al [18] evaluated the viability of the beverage based on fresh whey inoculated with L. casei.…”