Thermal kinetics of enzyme inactivation, color changes, and allicin degradation of garlic under blanching treatments

Abstract

AbstractBlanching is a feasible and effective method widely applied to prevent greening in garlic puree. However, this processing may cause the physical and chemical changes in garlic puree. Therefore, an investigation was carried out to systematically explore the effects of hot water blanching on enzyme inactivation (alliinase and γ‐glutamyl transpeptidase, GGT), discoloration, allicin degradation, and antioxidant capacity of garlic puree. The results showed that the inactivation of alliinase and GGT was strongly dependent on blanching temperature and time. Garlic puree turned into white when blanched at 80°C for 5 min or at 90°C for 4 min, with a* value of −3.24 ± 0.11, −2.80 ± 0.43, respectively. The inactivation kinetics of alliinase and GGT followed a first‐order reaction, as well as the kinetic of green discoloration. However, allicin content was dropped by 71, 80, and 85% after blanching for 5 min at 70, 80, and 90°C, respectively. A decline in the antioxidant capacity of garlic treated by blanching was also observed. The current findings indicated that blanching could contribute to inhabit garlic greening but had negative effects on the nutritional ingredients of garlic puree.Practical applicationsGarlic is prone to greening when processed into garlic puree, garlic juice and other products. The occurrence of greening seriously hindered the further processing of garlic. Blanching is an effective and feasible method to prevent greening in garlic puree. In this study, the effects of blanching on enzyme inactivation, color changes, allicin degradation and antioxidant capacity of garlic puree were studied. This study provides a theoretical basis for the deep processing of garlic.