Impact of antimicrobial bio-products on the base of dairy by-product on the quality of malted grains

Abstract

Lactobacillus sakei KTU05-6, Pediococcus acidilactici KTU05-7 and Pediococcus pentosaceus KTU05-9 producing bacteriocin-like inhibitory substances (collection of Department of Food Science and Technology, KTU) and Lactobacilus bulgaricus, obtained from KTU Food Research Institute, were adapted in a novel fermentation medium of dairy by-product (cheese whey and permeate). Novel fermented bio-products with different content of lactic acid isomers (lactic acid D(-) – 0,120-5,102 g/L or L(+) – 0,105-8,323 g/L), pH (4,2-8.93) were used for the treatment of Fusarium spp. contaminated wheat and barley malted grains (DON content in wheat – 1800 μg/kg and in barley - 1400 μg/kg) as well as for healthy grains. After the treatment the grains were left for growing (duration 3 days) under optimal conditions for germination (18-25 °C). The sprouting capacity and length of growth was determined. Furthermore, the antimicrobial effect of fermented product metabolites (lactic acid and it’s D(-) and L(+) stereoisomers) obtained using different LAB has been examined for malted grain safety. Fermented cheese whey with certain LAB (Pediococcus pentosaceus KTU05-9) was found to have a higher positive antimicrobial effect compared with a control medium (without the treatment) by lowering the fungal populations in malted grains. In the most antimicrobial active fermented products a L(+) isomer was found in the highest content (8,323 g/L). During the sprouting, lower variations and lower decrease in sprouting capacity were measured in the malted wheat grains in compare with barley. Based on the investigations of fermented product effect on sprouting capacity and antimicrobial tests, the conditions of LAB cultivation in dairy by-products have been selected.