Characterization of a short-term processing technology of black garlic with low 5-HMF content

Abstract

Black garlic, a deep-processed product of garlic, is widely favored in various Asian countries. Traditional black garlic production typically takes 60–90 days, resulting in low production efficiency and the formation of potentially harmful levels of 5-hydroxymethylfurfural (5-HMF). In this study, we implemented a novel production process capable of producing short-term black garlic (SBG) with significantly reduced levels of 5-HMF within just 8.6 h. A comparative analysis was conducted to investigate the quality disparities between SBG and commercially black garlic (CBG), encompassing assessments on color, physicochemical properties, characteristic components, in vitro antioxidant capacity, and volatile compounds. The results indicated that there were no significant differences in color between SBG and CBG. SBG exhibited higher levels of protein, reducing sugar, and polyphenols. 5-HMF, allicin, and S-allyl-l-cysteine (SAC) were selected as characteristic ingredients of black garlic. The concentration of 5-HMF in SBG was only 5.6% compared to CBG. SAC content in SBG was 2.3 times higher than in CBG and 11.3 times higher than in fresh garlic, while allicin was not detected in SBG samples. When comparing black garlic extracts at the same concentration, the antioxidant capacity of SBG was found to be stronger than that of CBG. Key flavor compounds identified in CBG included diallyl tetrasulfide, 5-methyl-2-furanmethanethiol, allyl methyl sulfide, dimethyl tetrasulfide, diallyl disulfide, diallyl sulfide, and dimethyl trisulfide. In contrast, key flavor compounds identified in SBG were 2-acetylthiophene, allyl methyl sulfide, 5-methyl-2-thiophenecarboxaldehyde, 2-acetylthiazole, dimethyl trisulfide, diallyl sulfide, and dimethyl disulfide. Compared to CBG samples, the aroma profile of SBGs exhibited a more pleasant scent with reduced pungency.