Phenolic Compounds From Brewer's Spent Grains: Toward Green Recovery Methods and Applications in the Cosmetic Industry

Rodrigo Macias-Garbett,Sergio Othón Serna-Hernández,Juan Eduardo Sosa-Hernández,Roberto Parra-Saldívar

doi:10.3389/fsufs.2021.681684

Rodrigo Macias-Garbett, Sergio Othón Serna-Hernández + Show 2 more

Open Access

https://doi.org/10.3389/fsufs.2021.681684

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Abstract

Brewers' spent grain (BSG) is the main by-product derived from the brewing industry, where it accounts for 85% of the total waste generated. The total annual production worldwide of this waste is 39 million tons. This lignocellulosic material is traditionally used as cattle feed and sold at a low retail price (~USD 45.00 per ton). However, efforts for the revalorization of this by-product are emerging since research has established that it can be used as a low-cost source of bioactive molecules and commodity chemicals that can bring value to integral biorefinery ventures. Among commodities, phenolic compounds have attracted attention as added-value products due to their antioxidant properties with applications in the food, cosmetic, and pharmaceutical industries. These phytochemicals have been associated with antiaging and anticancer activities that have potential applications on cosmetic products. This mini-review summarizes the most relevant extraction techniques used for the recovery of phenolic compounds from BSG while discussing their advantages and shortcomings and the potential applications from BSG bioactive extracts in the cosmetic industry and their reported beneficial effects. This mini-review also makes a brief comment on the role of phenolic compounds extraction in the economic feasibility of an integral BSG biorefinery.

Highlights

Beer manufacturing involves many processes and different ingredients; many waste or by-products are generated
An in vitro study conducted by Almendinger et al (2020) was made regarding the use of phenolic compounds obtained by aqueous extraction from Brewers’ spent grain (BSG) and applied to skincare products; the tyrosinase inhibition and antioxidant activity were determined for different phenolic concentrations ranging from 1 to 10% (v/v) for cellular antioxidant activity and from 0.1 to 1% for tyrosinase inhibition activity
The results obtained from this study showed that there was a positive correlation between the number of phenolic compounds and antioxidant activity; the higher concentration of phenolic compounds, the higher was tyrosinases’ inhibition rate (Almendinger et al, 2020)

Summary

Introduction

Beer manufacturing involves many processes and different ingredients; many waste or by-products are generated. On another reported green pre-treatment, Kumari et al (2019) applied a pulsed electric field technology on light and dark BSG to enhance the extraction of bioactive compounds. The Soxhlet method offers time improvements over the conventional LSE of BSG phenolic compounds and is a wellestablished technique with high reproducibility (Guido and Moreira, 2017).

Results

Conclusion