Optimisation of fermentation processes of local cereal-based beverages to produce improved cereal based probiotic beverages.

Abstract

Fermented cereal-based probiotic beverages are rare and have rarely been produced in Tanzania. Though the beverages are novel, the potentiality of such beverages has for some decades been exhibited through local fermented cereal-based beverages. In recent years there has been a paradigm shift towards non-diary probiotic products because of the negative health effects milk and dairy products have on the multitude of people around the world. A quantitative study employing purposeful sampling was carried out in three regions of Mbeya, Morogoro and Kilimanjaro whereby in each of the regions; quadruplicate samples of either of the traditional cereal-based beverages locally known as Kindi, Kimpumu, Togwa or Mbege were collected from a target village and stored at 4 °C in the laboratory. Identification of probiotic microbes in the local beverages was done and probiotic Kindi, Kimpumu, Mbege and Togwa were developed using pure cultures of the identified probiotic bacteria. Probiotic cultures used were Lactobacillus brevis for Togwa, Lactobacillus plantarum for Kimpumu and Mbege and Pediococcus pentosaceus for Kindi. After 24-48 h of controlled fermentation at 37 °C; results showed that the prepared cereal-based beverages were probiotic with mean viable cell counts of 1 x 1011 cfu/mL and mean pH 4.77. During storage the probiotic cereal beverages remained stable for five days at 25 °C and 28 days (4 weeks) at 4 °C with viable cell count of 2.0 x 1011 cfu/mL and pH 3.83 at 25 °C and viable cell count of 2.0 x 1011 cfu/mL and pH 4.08 at 4 °C, respectively. There was no growth of pathogens in the beverages. The four cereal based probiotic beverages were equally accepted by consumers through a sensorial evaluation. This study shows that controlled fermentation of cereals using carefully selected probiotic bacteria results in probiotic cereal based-beverages with good quality attributes and safety and further advance the knowledge on fermented cereal substrates as nutrient-rich and promising delivery vehicles for probiotics by sustaining the growth of a large population of lactic acid bacteria.