Inhibitory activities and mechanism of hydrocolloids against toxic maillard reaction products formation in roast beef

Abstract

Maillard reaction in foods gives rise to toxic byproducts such as heterocyclic amines (HAs), acrylamide (AA) and advanced glycation end products (AGEs). Inhibition of their formation during thermal processing is the most practical way to minimize their dietary exposure and thus the associated health risks. Hydrocolloids have attracted increasing attention due to their unique structural diversities that enable them to actively participate in Maillard reaction to mitigate the formation of toxic byproducts. Firstly, in this study, the effects of six hydrocolloids, including alginic acid, sodium carboxymethylcellulose (CMC-Na), chitosan (Chi), carrageenan, konjac glucomannan (KGM) and xanthan gum, on major HAs formation (PhIP, MeIQx and 4,8-DiMeIQx) in both chemical model systems and roast beef patties were investigated. Results in chemical models showed all the six tested hydrocolloids effectively inhibited PhIP formation by 19.3-42.7% at lower doses (5 and 10 mg), while they exhibited better inhibitory effects against MeIQx formation at higher dose (30 mg). Among them, CMC-Na had the strongest inhibitory effect, followed by Chi in roast beef patties. Marination with CMC-Na solution led to even greater inhibitory effects than its powder form. Further analysis showed Chi, but not CMC-Na, synergized with phloridzin to inhibit HAs formation in roast beef. Secondly, the effects of different kinds of chitosan, polymer (Chi), oligomer (ChiO) and monomer (Gluco), and their combinations with flavonoid aglycones and glycosides against HAs formation were investigated to find out potential combination partners for enhanced suppression of HA formation. Results in roast beef patties showed Chi, ChiO and Gluco significantly inhibited PhIP and MeIQx formation by 43-80% and 31-57%, respectively. Among them, ChiO was the most effective, followed by Chi. In combinations with flavonoid glycosides (phloridzin, rutin and hesperidzin, respectively), Chi, but not ChiO, generated enhanced inhibitory effects. Further analysis showed Chi and phloridzin combined at a ratio of 1:1 was the most promising, especially against PhIP formation, and the mechanism behind likely involved: 1) water retention by Chi, and 2) reduction of phenylalanine availability to form phenylacetaldehyde for PhIP formation. Thirdly, the effect of Chi-flavonoid combinations against total AGEs formation were further evaluated. Results in roast beef patties showed Chi combined with flavonoid aglycones (phloretin, quercetin, and hesperetin, respectively) resulted in significantly enhanced inhibitory effects (60-79% inhibition) against AGEs formation compared to single agents. Further analysis showed Chi and quercetin combined at various mass ratios could all generate significantly enhanced inhibition against AGEs formation in roast beef, which could be mainly attributed to the inhibited reaction of GO with protein and reduced lipid peroxidation. Meanwhile, the optimal combinatorial approach (2:1, Chi to quercetin) would not cause negative effect on the color characteristics but could contribute to synergistic improvements of the texture properties of roast beef patties. In summary, these findings suggest that hydrocolloids are potent HA formation inhibitors and appropriate combination of Chi and certain flavonoids could contribute to significant improvement in the safety of heat-processed meat products, which could also open up an avenue for broadening the application of flavonoids in foods.