Fungal deterioration is a barrier to the wide acceptance of fermented cereal foods from Africa.The use of protective cultures is a natural approach to controlling fungi in foods that also complies with a clean label s...Fungal deterioration is a barrier to the wide acceptance of fermented cereal foods from Africa.The use of protective cultures is a natural approach to controlling fungi in foods that also complies with a clean label strategy.This study aims to select antifungal lactic acid bacteria(LAB)previously isolated from kunu-zaki to bio-control deterioration in this cereal-based Nigerian fermented beverage.Strains of Leuconostoc citreum(1),Limosilactobacillus fermentum(6),and Weissella confusa(3)were the most active against seven test mold species,with average inhibition score of 2.25-2.88,after screening 220 LAB strains using agar overlay on millet-sorghum flour hydrolysate(MSFH)agar.The MSFH agar diffusion method revealed that antifungal activity against the seven target molds was retained in cell-free supernatants(CFSs)of selected LABs,with the strongest inhibition against A.flavus F008BA and P.citrinum 3AS1 demonstrated by L.fermentum 5KJEU5(9.06%)and W.confusa YKDIA1(24.55%),respectively.The antifungal activity of CFSs was mainly due to the occurrence of acidic compounds,with the most abundant compounds being acetic(0.30-1.96 mg/mL)and lactic(1.80-3.23 mg/mL)acids.Other compounds such as hydroxycaffeic(0.16-6.72μg/mL),3-(4-hydroxyphenyl)propionic(1.40-6.36μg/mL),3-phenyllactic(1.28-24.48μg/mL),and hydroxyferulic acids(12.25μg/mL)occurred at lower concentrations.In challenged kunu-zaki,L.fermentum 5KJEU5 prevented the growth of A.flavus F008BA and P.citrinum 3AS1 beyond 8 day at ambient temperature(25◦C).In this study,LAB from kunu-zaki displayed strong antifungal activity,showing great potential as a protective culture to prevent fungal growth and mycotoxin accumulation in cereal foods.展开更多
基金supported by Swiss Government Excellence Scholarships for Foreign Scholars and Artists(2018-2019)Cost Action CA18101 SOURDOMICS“SOURDOugh biotechnology network towards novel,healthier and sustainable food and bIoproCesseS”is also thankfully acknowledged.
文摘Fungal deterioration is a barrier to the wide acceptance of fermented cereal foods from Africa.The use of protective cultures is a natural approach to controlling fungi in foods that also complies with a clean label strategy.This study aims to select antifungal lactic acid bacteria(LAB)previously isolated from kunu-zaki to bio-control deterioration in this cereal-based Nigerian fermented beverage.Strains of Leuconostoc citreum(1),Limosilactobacillus fermentum(6),and Weissella confusa(3)were the most active against seven test mold species,with average inhibition score of 2.25-2.88,after screening 220 LAB strains using agar overlay on millet-sorghum flour hydrolysate(MSFH)agar.The MSFH agar diffusion method revealed that antifungal activity against the seven target molds was retained in cell-free supernatants(CFSs)of selected LABs,with the strongest inhibition against A.flavus F008BA and P.citrinum 3AS1 demonstrated by L.fermentum 5KJEU5(9.06%)and W.confusa YKDIA1(24.55%),respectively.The antifungal activity of CFSs was mainly due to the occurrence of acidic compounds,with the most abundant compounds being acetic(0.30-1.96 mg/mL)and lactic(1.80-3.23 mg/mL)acids.Other compounds such as hydroxycaffeic(0.16-6.72μg/mL),3-(4-hydroxyphenyl)propionic(1.40-6.36μg/mL),3-phenyllactic(1.28-24.48μg/mL),and hydroxyferulic acids(12.25μg/mL)occurred at lower concentrations.In challenged kunu-zaki,L.fermentum 5KJEU5 prevented the growth of A.flavus F008BA and P.citrinum 3AS1 beyond 8 day at ambient temperature(25◦C).In this study,LAB from kunu-zaki displayed strong antifungal activity,showing great potential as a protective culture to prevent fungal growth and mycotoxin accumulation in cereal foods.