Effect of different processing techniques on quality of black garlic products

Black garlic is a new kind of garlic product. Two different black garlic products, namely No. 1 and No. 2, were obtained using different processing techniques; the production cycle of black garlic No. 1 was three times as long as that of No. 2. In this study, the effects of two different processing techniques on the nutrient composition, allin content, and free radical scavenging capacity of black garlic products were compared. The results revealed that the moisture (around 40%) and alliin contents of the black garlic products were less than those of fresh garlic, and black garlic contained more soluble sugar, protein, and polyphenols than fresh garlic on a wet basis. With the exception of polyphenols, the other contents decreased on a dry basis; the proline and arginine contents decreased significantly, with coefficients of variation of 1.03 and 1.12, respectively. On a wet basis, the OH· radical scavenging capacity of black garlic was similar to that of fresh garlic, and the DPPH· scavenging capacity of black garlic was twice as much as that of fresh garlic. The crude protein content of black garlic No. 1 was lower than that of black garlic No. 2, while the soluble sugar, polyphenol, and alliin contents were greater. The coefficients of variation of crude protein and polyphenol contents were about 0.20, and there were significant differences (P < 0.05) among all components. The extracts from the two black garlic products showed equivalent OH· and DPPH· scavenging capacities at various concentrations. When the extract concentration was 0.05 g/mL, more than 90% of the OH· and DPPH· radicals were scavenged. The two black garlic products could be distinguished using an electronic tongue. ©, 2015, South China University of Technology. All right reserved.