Characterisation of melanoidins derived from Brewers' spent grain: new insights into their structure and antioxidant activity

Abstract

Melanoidins, formed at the final stages of Maillard reaction (MR), present important physiological activities, but their structure and reaction pathways are largely unknown in real food systems. In the present work, these bioactive compounds derived from Brewers' spent grain (BSG) with different roasting degrees were analysed. Results showed that BSG could be considered a more important source of bioavailable antioxidants than what it was reported in previous studies. During MR development, proteinic structures are partially lost while a carbohydrate skeleton is formed. The crystallinity is reduced and the structure sets into a conformation with a peak centred at 20°(2h), stable with the increasing thermal treatment. While MR continues the development of browning compounds increases, the antioxidant activity rises and phenolic compounds are bind to the melanoidin structure (P ≤ 0.05). Moreover, FTIR analysis showed a dominance of a-glyosidic linkage and the presence of furanose rings in the melanoidins structure.

The variability of physico-chemical properties of brewery spent grain from 8 different breweries

“…Besides protein content, significant differences (p < 0.05) were also shown in fat and carbohydrate contents. BSG fat content from BSG was noted for its potential as a source of antioxidants, fatty acids, and volatile tocotrienol compounds ( Bohnsack et al., 2011 ; del Río et al., 2013 ; Fărcaş et al., 2015 ; Parekh et al., 2017 ; Patel et al., 2018 ; Patrignani and González-Forte, 2020 ; Ribau Teixeira et al., 2020 ). The carbohydrate content roughly describes the fiber amount.…”

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

“…Along with phenolic compounds, the BSG extracts' antioxidant activity has been attributed to a synergic action of melanoidin compounds produced in the malting Maillard reaction, heightening the interest for their co-extraction. In the specific topic of the application of green recovery methods on BSG, coupled melanoidin extraction has been documented by Patrignani and González-Forte (2021), where the application of a microwave treatment was attributed as a promoter of Maillard reaction-derived products and the enhanced antioxidant activity of microwave-treated extracts was associated to a coupling of phenolic acid and melanoidin effects. 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.…”

Evaluation of the technological functional properties and antioxidant activity of protein hydrolysate obtained from brewers' spent grain

“…The presence of NFC may have an impact on the antioxidant activity of BSG as well. The analysis of bioactive compounds derived from BSG with different roasting degrees revealed that while the Maillard reaction continues the development of melanoidins increases, the antioxidant activity rises and phenolic compounds are bound to the melanoidin structure (Patrignani & González‐Forte, 2021). It can also be observed that the content of lipids and ash significantly decreased ( p < .05) in the protein concentrate, which can be explained by the extraction method.…”