Evaluation on the physicochemical and digestive properties of melanoidin from black garlic and their antioxidant activities in vitro

As the important compounds in black garlic, the physicochemical properties and bioactivities of melanoidin (MLD) were investigated in this study. The results showed that MLD possessed strong metal-ion chelating capacity and radical scavenging activities which were positively correlative with molecular weight (MW). During the simulated digestion in vitro, the ultraviolet absorption, browning degree and MW distribution of MLD remained the same as initial. It proved that the MLD from black garlic could be indigestible like the dietary fiber with little loss of volatile compounds and polysaccharides. Remarkably, the bioactivities of MLD were reduced significantly under the treatment of alpha-amylase or hydrochloric acid, while they were stable and retained over 60% after adding pepsin and pancreatin. This study provides fundamental evidences for further research and widely application of MLD and black garlic in the production of functional food or food additives.

Automated summary

This study investigated the physicochemical properties and bioactivities of melanoidin (MLD) as an important compound in black garlic. The results showed that MLD had strong metal-ion chelating capacity and radical scavenging activities, positively correlated with molecular weight. Additionally, MLD remained unchanged during simulated digestion, indicating its resistance to digestion similar to dietary fiber. It was found that the bioactivities of MLD were significantly reduced under certain treatments, but stable and retained after adding specific enzymes, providing insights for further research and application in functional food production.