Prebiotics extracted from fruits and vegetables can be applied to lactic acid bacteria to improve their antioxidant activity

Prebiotics are food alternatives that promote health by supporting microbes in the digestive system. This study aimed to pretreat vegetables and fruits to release prebiotics for the growth of probiotic lactic acid bacteria (LAB). Powdered fruit (mango, pineapple, and papaya) and vegetable (asparagus and kale) samples were subjected to chemical-thermal pretreatment with 3 % (w/v) gluconic acid at 121 °C. Afterward, carbohydrates were precipitated from the hydrolysates by ethanol precipitation . Fourier transform infrared spectroscopy revealed that xylan and pectin were the main polysaccharide components in the precipitates. The reducing sugar contents of the hydrolysates were determined, and their ability to promote LAB growth was compared with that of glucose. Interestingly, all LAB strains could utilize plant hydrolysates as the sole nutrient source, indicating that after extraction, all the nutrient components were effectively released and available for LAB growth. The Mahachanok mango and kale hydrolysates increased growth and presented significantly greater prebiotic activities, with scores of 0.31 ± 0.02 and 0.23 ± 0.01, respectively, for Lactiplantibacillus plantarum FL10. Although only 50 % of the FL10 cells remained viable after spray drying, their antioxidant activity was preserved. The spray-dried powders from Mahachanok mango and kale hydrolysates fermented with FL10 increased the free radical scavenging activity from 27.63 % to 63.38 % and 29.31 % to 71.13 %, respectively. Herein, we demonstrated the benefits associated with dry powder products that can be used as food additives while maintaining the antioxidant properties of Mahachanok mango and kale after fermentation with LAB. • Pretreated Mahachanok mango and kale precipitates contained xylan and pectin. • The highest growth and prebiotic scores of L . plantarum FL10 were attained with Mahachanok mango and kale hydrolysates. • Fermentation of Mahachanok mango and kale powders with FL10 significantly increased their antioxidant activity . • Spray drying preserved the antioxidant activity of Mahachanok mango and kale hydrolysates. • Antioxidant activity in fermented powders resulted from lactic acid bacteria interacting with phenolic compounds.