Optimizing Skim Milk medium for production of postbiotic cocktail with high antioxidant activity obtained from Lactobacilus spp

BACKGROUND AND OBJECTIVESProbiotics, along with their postbiotic metabolites, have beneficial effects on human health. Adopting a healthy lifestyle which includes natural antioxidants such as postbiotics, can prevent oxidative stress. In the industrial sector, the use of nutritional mediums at specific concentrations in combination with prebiotics (essential elements which fermented by live cells of bacteria) is required to produce -potential postbiotics, such as those with antioxidant activity. The objective of this investigation was to enhance the antioxidant capacity of postbiotics by optimizing skim milk medium in combination with sucrose (prebiotic).MATERIAL AND METHODS:In this investigation, four concentrations of skim milk (۲%, ۳%, ۵%, and ۱۰%) were produced, and each concentration was divided into four sections. Subsequently, four concentrations of sucrose (۰.۵%, ۱.۵%, ۲.۵%, and ۱۰%) were separately added to each section. To prepare the postbiotic cocktail, initially, ۱۰ Lactobacilus strains, consisting of L. casei ۳۷۵, L. casei ۴۴۱, L. brevis ۱۶۵, L. brevis ۲۰۶, L. reuteri ۱۱۷, L. reuteri ۱۱۸, L. fermentum ۶۰, L. rhamnusus ۶۶, L. plantarum ۴۶۹, and L. plantarum ۲۶۶ which obtained from healthy human feces were cultured in MRS medium (at ۳۷°C for ۱۸ hours). Then, the mixture of ۱۰ strains with specific concentration (۱۰۹ cfu/ml) inoculated in specific prepared skim milk medias and incubated for ۹۶ h at ۳۷°C in aerobic condition. Following bacterial growth, the postbiotic cocktail was obtained by centrifugation and filtration. To evaluate the antioxidant activity of postbiotic cocktail, biochemical tests, including DPPH, ABTS, HRS, superoxide onion, lipid peroxidation, and reducing power, were employed.RESULTSBased on the findings, it was observed that there was an increase in antioxidant potential with an elevation of concentration of skim milk and decrease in concentrations of sucrose. Thus the postbiotic mixture demonstrated heightened antioxidant potential in all biochemical assessments conducted in a skim milk substrate with a concentration of ۵%, accompanied by ۰.۵% sucrose.CONCLUSIONThe findings have demonstrated that by means of refining the nutrient medium, the efficacy of the postbiotic mixture can be elevated, rendering it a viable candidate for employment in a diverse array of industries such as the dairy, pharmacological and clinical sectors.

کلیدواژه ها:

Antioxidant activity ، postbiotic ، skim milk ، sucrose