Drying of probiotic fruit juice can be a good alternative for new probiotic foodstuff production since most probiotic foods are dairy-based products, which are not suitable for people with galactosemia, lactose intolerance or allergy to milk protein. Thus, the aim of this study was to evaluate the influence of spray and spouted bed drying and feed flow rate on the microorganism survival and physicochemical properties of probiotic orange juice powder. Fermented probiotic orange juice containing Lactobacillus casei NRRL B-442 was spraydried at 140 °C and spouted bed dried at 60 °C, respectively. Three different feed flow rates were studied for each equipment. Maltodextrin and gum Arabic were used as drying agents at 15% (w/w). The low temperature used in the spouted bed drying resulted in better probiotic bacteria viability compared to the product obtained by spray drying. Moisture and glass transition temperature were improved at the lowest feed flow rate (0.2 L/h), and faster rehydration time was achieved using maltodextrin. Thus, the spouted bed drying at low feed flow rates using maltodextrin as drying agent were the best parameters to produce powder fermented probiotic orange juice with high viability levels after drying and with good physicochemical parameters.

This study evaluated the influence of spouted bed drying temperature and maltodextrin dextrose equivalent on the probiotic microbial survival during drying and storage period and on physicochemical properties of fermented probiotic orange juice in powder. Probiotic orange juice was spouted bed dried at 60, 70, 80 and 90°C using maltodextrin with a different dextrose equivalent (10, 20, 30 and 39). After drying, the microbial was higher when lower drying temperatures were applied. During the storage, the highest drying temperatures (80 and 90°C) negatively affected the microorganism survival. On the other hand, at the lowest drying temperature (60°C), the product presented higher Aw, what negatively affected the microbial survival during storage. The temperature of 70°C was the best to preserve the microbial viability during storage. Physicochemical parameters were improved when temperature increased and dextrose equivalent decreased.

Características macroscópicas de actinobactérias: valorizando a diversidade do semiárido nas aulas práticas de microbiologia Macroscopic characteristics of actinobacteria: valuing the diversity of the semiarid in practical microbiology classes