T. VATAKIT AND B. LEENANON
Abstract
Probiotic products are mostly well known marketed in the type of fermented milks including yoghurt, yakult and acidophilus milk. However, with an increase in vegetarians throughout the developed countries, there is also a demand for the vegetarian probiotic products. Cereals offer another alternative for the production of functional foods as they could be used as fermentable substrates for the growth of probiotic microorganisms. Also, lactic acid bacteria isolated from traditional fermented cereal products could be used in a novel cereal based probiotic beverage production. This research was focused on the application of Lactobacillus pentosus PR01 which had been isolated from purple glutinous rice as probiotic. Moreover, to enhance the urvivability of Lb. pentosus PR01 up to at least the minimal therapeutic dose (eâ7logCFUmL- 1), implementation of prebiotics and cells encapsulation in fermented purple glutinous rice beverage was conducted. Prebiotics including inulin and fructooligosaccharides (FOS) at the concentrations of 0%, 1.0%, 2.0 % and 3.0% (w/v) were added to fermented purple glutinous rice beverage and it was found that 3.0 % inulin contributed the highest cell counts of Lb. pentosus PR01, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (pdâ0.05). For cells encapsulation, the cell suspension (~108 CFU mL-1) of Lb. pentosus PR01 in 0.1 % (w/v) peptone water was mixed with sterile sodium alginate solution at concentrations of 1.0%, 3.0% and 5.0% (w/v) at a ratio of 1:5 (v/v) and it was shown that 1.0 % (w/v) of sodium alginate was suitable for probiotic encapsulation since it contributed the highest in both cell density and % encapsulated yield (pdâ0.05). Also, scanning electron photographs of Lb. pentosus PR01 encapsulated beads with different sodium alginate concentrations were determined. Finally, free and encapsulated cells of Lb. pentosus PR01 in fermented rice beverage stored at 4°C on day 35 were investigated and it was shown that the encapsulated ones had the higher cell counts than the free cells with the cell numbers of 8.77 and 8.36 log CFUmL-1 and the surviving percentages as 98.54 and 94.00 %, respectively (pdâ0.05).