Effects of thermal treatment on alliin and its related sulfides during black garlic processing
Chunfeng Liu, Liandeng Lu, Chuanjia Yang, Chengtuo Niu, Jinjing Wang, Feiyun Zheng, Qi Li
Abstract
Black garlic (BG) is a kind of garlic intensive processing product, and its flavor and physiological activity are mainly derived from alliin and its related sulfides. The thermal stabilities of alliin, S-allyl-l-cysteine (S-ALC) and γ-glutamyl-cysteine (γ-GC) during BG processing were investigated in this study. The results showed that γ-GC was more stable than alliin and S-ALC, and the activities of alliinase, γ-glutamyl transpeptidase and γ-glutamyl-cysteine synthetase were completely inactivated at 50 °C for 18 h, so, the changes of alliin and related sulfides in subsequent stages didn't correlated with the three enzymes. Alliin and its related sulfides changed significantly during the Maillard reaction stage. Further researches showed that the total content of alliin, S-ALC and γ-GC in BG could increase by 20.1% under the optimal conditions where humidity at 90%, temperature at 80 °C, and the processing time at 210 h. The sensory analysis indicated that the optimal BG samples scored higher in color, dryness, garlic meat texture, smell, mouthfeel. In addition, the sour and sweet taste was more coordinated, and the bitterness was significantly reduced after the process optimization. These results could be helpful for the improving of BG processing technologies, products quality, and related physiological activity in food industry.