Effects of different processing methods on the antioxidant and immune stimulating abilities of garlic

In this study, we determined the antioxidant and immune stimulating abilities of a garlic product developed by freeze drying, heat drying, and solid‐state fermentation of heat‐dried garlic. Lactobacillus plantarum KCTC21004 and Leuconostoc mesenteroides KCTC13302 were used for the sample fermentation. The optimum conditions for fermentation were 50% (v/w) moisture, a fermentation time of 48 hr and a temperature of 37°C. Heat‐dried garlic samples fermented with L. plantarum KCTC21004 (HD21004) and L. mesenteroides KCTC13302 (HD13302) showed the highest flavonoid contents while heat‐dried garlic (HD) had the lowest flavonoid content. HD21004 contained the highest phenolic compounds, showed the highest antioxidant activity and demonstrated a strong immune stimulating effect while freeze‐dried garlic showed the lowest flavonoid and polyphenolic contents. Overall, the heat‐dried garlic samples (fermented and unfermented) contained about three times more S‐Allylcysteine (SAC) than the freeze‐dried samples (FD). The current study demonstrates that heat drying and subsequent fermentation of garlic with L. plantarum KCTC21004 can improve its therapeutic effects.