The optimum processing conditions for microbial viability (initial pH 5.8 and 31 °C) were chosen in which to evaluate juice fermentation over 24 h. Fig. 2 presents the microbial viability (Log CFU/mL) and the juice pH during the course of fermentation. Over 24 h of fermentation, a sharp increase of microbial viability was observed from 8 to 10 h of fermentation, reaching 8.34 Log CFU/mL. No significant increase was observed thereafter up to 24 h of fermentation when the viability reached 8.65 Log CFU/mL. Stopping the process at 10 h could lead to a pH value too close to that of 4.5, which is the

threshold considered for the development of many pathogens in food. On the other hand, allowing an additional 2 h of fermentation, the pH dropped to 4.21, which is safer for product storage (Fig. 2a). This pH decrease was due to lactic acid production because of the microbial growth, as seen in the 12 h fermentation window (Fig. 2b). The results presented Bosutinib mw herein are in agreement with other studies (Gupta et al., 2010 and Yoon et al., 2006), which suggested that different vegetable matrices could serve as good media for growing probiotics by stimulating their growth, resulting in good viable counts. Maximal

growth was obtained at different conditions of cell viability. However, cell viability check details is the key factor for a functional product. Thus, the optimum conditions for cell viability were applied to the kinetic study. Usually, Lactobacilli strains are reported Aldol condensation to present optimum growth at 37 °C and pH around 6.5. Nazarro, Fratianni, Sada, and Orlando (2008) evaluated the possibility of

producing a functional vegetaable beverage based on the growth of Lactobacillus rhamnosus and Lactobacillus bulgaricus in carrot juice. Both bacterial strains were capable of growing in carrot juice, reaching nearly 9 Log CFU/mL after 48 h of fermentation, and the pH was reduced to 3.5–3.7 or below. As reported elsewhere, the results presented herein confirm that microbial survival in foods is strongly dependent on the food matrix ( Shah, 2007). Fig. 3 shows the carbohydrate consumption that occurred during the fermentation. The major sugar in pineapple juice was sucrose (∼86%). Sucrose decreased during the fermentation while glucose and fructose increased. Carbohydrates are consumed during the fermentation due to the microbial growth. The pH decreased due to lactic acid production and sucrose hydrolysis occurred due to low pH values. From data presented in Fig. 3, the rate of sucrose hydrolysis was faster than that of sugar consumption, thus resulting in an increase of reducing sugars. A newly fermented sample was prepared using the optimised conditions (initial pH of 5.8, 31 °C and 12 h of fermentation) for the storage stability assay. After 12 h of fermentation, the juice was divided into two sample categories: sweetened samples containing 10% w/v of table sugar (sucrose) and non-sweetened samples.