Potential application of four types of tropical fruits in lactic fermentation

- Four types of tropical fruit and whey were investigated as substrates for lactic fermentation.
- Fermented lactic beverage from mango and guava juice presented the highest sensorial acceptance and microbial growth.
- Carambola pulp presented an inhibitory effect on the development of the lactic culture.
- Pitaya pulp presented a longer lag phase than the other formulations.

Fruit juice has been used for the production of lactose-free or low-lactose beverages. This study evaluated the potential of four types of tropical fruit (carambola, guava, mango and pitaya) for the production of fermented lactic beverages with and without whey addition. Pasteurized fruit juices were used at (% v/v): 100% fruit juice, 100% whey and 50:50% of juice: whey. The fermentations were conducted with a lactic culture (L. casei, S. thermophilus, and L. bulgaricus) at 37 °C for 72 h. The final characteristics obtained were pH 3.0-4.0, soluble solids concentration (SS) 5.0-7.0 °Brix (g/100 g), and acidity 0.2-1.0 %w/v. A validation test obtained 4.0-4.8 (pH), 6.0 °Brix (SS), and 0.30-0.50 %w/v (acidity) at 24 h. The lactic bacteria had better growth (107-108 CFU/mL) and the highest sensory acceptance rates (70% for taste, 75% for flavor and 90% for color) utilizing mango or guava. Carambola and pitaya caused a partial inhibition to the cellular growth (103-104 CFU/mL) and resulted in beverages with lower sensory acceptance. In all cases, formulations containing only fruit juice were lactose-free and better sensory acceptance than the ones with of whey.