Ohmic heating pretreatment accelerates black garlic processing

Abstract

Black garlic (BG) is obtained by the Maillard reaction under controlled conditions of temperature and humidity. This study describes the traditional processing (TT-BG) and the use of ohmic heating (OH) as pre-treatment (OH-BG) to improve time processing. Physicochemical composition and sensory properties were of particular interest in this study. The OH as a pretreatment causes the hydrolysis of fructans to fructose, which are degraded during storage under traditional treatment conditions (70 °C/94% RH) through the Maillard reaction causing the faster formation of compounds responsible for the color of black garlic compared to black garlic without pre-treatment. This reaction cuts down the time to attain the characteristic color of black garlic from 30 to 12 days. The 5-hydroxymethyl-2-furaldehyde (HMF) content was 3.6 times higher in OH-BG than in TT-BG. The polyphenol content and antioxidant capacity did not show differences between TT-BG and OH-BG, but their levels were superior to commercial sample. Both products (OH-BG and TT-BG) were sweet (36.8 and 31.6 °Bx, respectively) and had an excellent organoleptic acceptance (75 and 70%). These results highlight the potential of ohmic heating pretreatment in reducing the time to obtain good quality BG.