Determination of the effects of steaming and blanching pre-treatment processes on the physicochemical properties, antioxidant activities, and 5-hydroxymethylfurfural and S-allyl cysteine contents of black garlic

Abstract This study investigated the effects of steaming and blanching pre-treatments on the physicochemical properties, bioactive compound content, and antioxidant activity of black garlic during fermentation. Moisture content and pH decreased over fermentation time, while titratable acidity increased. Pre-treatments enhanced the total phenolic, flavonoid, and flavonol contents, as well as antioxidant activity (DPPH, ABTS+, FRAP), compared to control samples, with steaming pre-treatment being more effective than boiling. 5-HMF and S-allyl cysteine (SAC) levels were optimised with pre-treatments, promoting the formation of bioactive compounds. These methods offer an efficient, cost-effective way to enhance black garlic production, shorten processing times, and improve its nutritional and economic value.