According to a new publication by researchers from Italian company Recusol and the Universities of Camerino and Bologna that was published in a Cosmetics supplement entitled Green Ingredients in Cosmetics & Food, waste from the production of craft beers “can be an interesting source of phenols for the preparation of skin anti-ageing”.

The researchers took extracts from starting materials (malts, hops, and yeast), intermediate products and the final waste products in multiple craft beers taken from water or 70° alcohol, and evaluated their total phenol content and antioxidant activity

Total phenol content, as measured by the Folin Ciocalteau assay, varied with the specific product. The highest values, 93-155 mg GAE/g, were found in starting hops, intermediate ones in starting malt and starting yeast, and the lowest values in wort. Total phenol content in the final beers depended on the phenols extracted from the different ingredients.

The method used to evaluate antioxidant activity strongly influenced the results.  In general, though, 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”.

Interestingly, the authors added, waste yeast frequently showed higher values than did starting material, possibly because yeast is able to absorb phenols from the beer during brewing. Preliminary in vitro assays in keratinocyte HaCaT cells were carried out to assess the potential bioactivity of spent extracts. Hop and yeast extracts showed the ability to improve the mitochondrial activity and prevent oxidative stress in HaCaT cells, two important features in skin ageing.

Cosmetics 2021, 8(4), 96; https://doi.org/10.3390/cosmetics8040096