Pulsed vacuum pickling (PVP) of garlic cloves: Mass transfer kinetics and quality attributes

Abstract

Due to special taste and medicinal properties, pickled sweat-sour garlic is one of the most popular garlic-based functional foods in China. The traditional pickling method of garlic is tedious, time consuming, laborious, low efficient, and easily influenced by environmental factors and microorganisms. In the present study, garlic cloves were subjected to two pickling methods: osmotic dehydration at atmospheric conditions (OD) and pulsed vacuum osmotic dehydration (PVOD). Pulsed vacuum impregnation was applied in order to evaluate the possibility of enhancement of pickling efficiency and quality of final product. The effect of OD and PVOD on mass transfer kinetics of sodium chloride, sucrose and acetic acid as well as quality attributes (color parameters such as L*, a*, b*, and thiosulfinates content) of pickled sweet and sour garlic cloves was investigated. Results indicate that PVOD promoted mass transfer of sodium chloride and acetic acid compared to the traditional OD method. However, there was no significant effect on mass transfer of sugar. PVOD significantly decreased thiosulfinates content (from 4.49 mg/mL to 1.91 mg/mL) and L* values (from 66.72 to 45.85) of garlic. During PVOD of garlic, samples gradually turned from white color to the desired amber color during the PVOD process. The findings of current work indicate that PVOD is a promising technique for garlic pickling as it enhances mass transfer and accelerates the degradation of thiosulfinates content in garlic.