Use of whey for a sustainable production of postbiotics with potential bioactive metabolites

Abstract

Postbiotics have gained attention due to their health benefits and potential bioactive metabolites. Short-chain fatty acids (SCFAs) have been identified within these metabolites, which are related to anti-inflammatory properties and antioxidant activity, among others. For the food industry, it is important to consider a suitable culture medium for postbiotic production. Whey, as a by-product from the cheese industry, is rich in nutrients and is proposed to support this purpose. This study is aimed to evaluate the microbial growth of three probiotics, Lactiplantibacillus plantarum 299v, Lacticaseibacillus casei Shirota, and Bifidobacterium animalis subsp. lactis BPL1, using a whey culture medium supplemented with soluble fibres (inulin or chia mucilage) at two concentrations (1% or 2% w/w). Also, analyse the effect of soluble fibres on the production of SCFAs and the antioxidant activity of cell-free supernatant as postbiotics. SCFA production was quantified by HPLC and antioxidant activity was determined by the DPPH⁺ assay and the KMnO₄ agar method. The formulated culture media promoted the growth of probiotics, especially those added with inulin. Lactiplantibacillus plantarum 299v and Lacticaseibacillus casei Shirota produced primary lactic and acetic acid. B. lactis BPL1 had the highest SCFAs production in the culture medium with 2% w/w of inulin. The antioxidant activity from Lactiplantibacillus plantarum 299v postbiotics was significantly improved with soluble fibres (p < 0.05). This study shows postbiotics are produced with a sustainable approach. Moreover, postbiotics based on whey and soluble fibres can be a potential ingredient for the formulation of new food products as sources of SCFAs and antioxidants.