Fermented water-soluble yam extract: growth kinetics, technological characteristics and sensory evaluation

Extrato hidrossolúvel fermentado de inhame: cinética de crescimento, características tecnológicas e avaliação sensorial

The shifting behavior of the contemporary population regarding ethical animal welfare concerns has driven an increased demand for plant-based foods and beverages. Thus, this study developed a water-soluble fermented yam extract (FWYE) using commercial strains of Lactobacillus bulgaricus and Streptococcus thermophilus, and evaluated its fermentation kinetics, microbial viability, technological properties during storage and sensory attributes. Lactic acid bacteria (LAB) adapted to the mathematical model within the tested matrix. During the storage period, the pH of the FWYE decreased, with the most pronounced reduction observed on day 21 (3.99), which coincided with the lowest counts of L. bulgaricus (6.73 log CFU/mL) and S. thermophilus (6.68 log CFU/mL). After 28 days of refrigerated storage, FWYE maintained LAB counts above 8.4 log CFU/mL. The technological properties exhibited syneresis values exceeding 77.92% and water retention capacity below 9.38%. For the sensory evaluation, 70 panelists assessed FWYE alongside strawberry-flavored (FWYES) and chocolate-flavored (FWYEC) versions. The highest scores for sensory attributes, as well as the greatest acceptability index (83.8%) and purchase intention (3.97), were recorded for FWYES. The results show that despite technological limitations, the fermented yam beverage proved effective in maintaining the viability of LAB and sensorially promising for consumers with restrictions on dairy consumption.

Key words:
lactic acid bacteria; plant based; fermentation; strawberry; veganism