New Antioxidant Ingredients from Brewery By-Products for Cosmetic Formulations

The purpose of this work was to evaluate the total phenol content and antioxidant activity of different types of handcrafted beers (Ego, Alter, Fiat Lux, Triplo Malto, Ubi, and Maior), as well as the starting materials (malts, hops, and yeast), the intermediate products, and the waste products (spent malts, hops, and yeast), in view of their use in innovative cosmetic formulations. Extractions from starting and spent samples were taken from water or 70° alcohol. The total phenol content (Folin Ciocalteau Essay) of all the brewing products depended on the specific product under investigation. The highest values were found in starting hops (ranging from approximately 93 to 155 mg GAE/g, according to the extraction solvent), intermediate ones in starting malt and starting yeast, and the lowest values in wort. The total phenol content in the final beers originates from the phenols that were extracted from the different ingredients, namely the starting malts, hops and yeast, but non-negligible values were still observed in spent products. The method used for the evaluation of the antioxidant activity, trolox equivalent antioxidant capacity (DPPH), ferric-ion reducing antioxidant parameter (FRAP), and radical cation scavenging activity and reducing power (ABTS) strongly influenced the results. In general, the results reflected the trend observed for the total phenol content: that beers are progressively enriched by phenols originating from all the starting ingredients, and that spent products still possess non-negligible antioxidant activity. It is interesting to note that waste yeast frequently showed higher values than those of the starting material; it can be inferred that yeast is able to absorb phenols from the beer during brewing. By considering the interest in exploiting waste derived from processing foods, the biological activity of waste Alter brewery products has been evaluated on a cell culture of keratinocytes (spent products of malt, hop, and yeast). Preliminary in vitro assays in keratinocyte HaCaT cells were carried out to assess the potential bioactivity of spent extracts. Among the spent extracts, the spent hop and yeast extracts showed the ability to improve the mitochondrial activity and prevent oxidative stress in HaCaT cells, two features in skin ageing. In conclusion, this study offers evidence that waste from handcrafted beers can be an interesting source of phenols for the preparation of skin anti-aging cosmetics.