Abstract

In order to contribute to the diversification of the range of probiotic products, limited until now to the dairy matrices, and to valorize the local raw materials of Cameroon, we set ourselves the objective of finding the conditions of fermentation of the fresh sap of Rafia farinifera by two probiotic ferments, namely, L. fermentum and B. bifidum. We first characterized raffia sap physico-chemically and studied the ability of ferments and their viability in the sap. The physico-chemical characteristics of the sap (3.801%±0.037 dry matter, 7.044±0.172 g of ash per 100 g of dry matter, 10.789±1.388 g of reducing sugars per liter, titratable acidity of 4.44 equivalent grams of lactic acid per liter, pH of 4.12, 2.91±0.94 g of total phenol compounds per liter, density of 1.158 g/l and a Brix of 4.2) and the viability of the ferments in the latter showed the feasibility of this work. Moreover, the optimization of physico-chemical parameters thanks to the Box-Behnken model after maximizing Brix, reducing sugars and proteins and setting the pH at 4, lactic acidity at 9 g/l, the amount of probiotics at 1.00 E+10CFU/ml led to the following operating conditions: B. bifidum and L. fermentum seeding rates of 10 and 2.82%, respectively, an incubation temperature of 37°C and an incubation time of 14 h 2 min. Thus, these conditions made it possible to obtain a drink having a titratable acidity of 8 g of lactic acid/l, a pH of 3.87, a protein content of 574.6 (mg/l), a Brix of 5.47 and a quantity of probiotics of 1.13 E+8 CFU/ml. Beyond this optimization, a sensory analysis performed on the optimized product showed that it was organoleptically acceptable.