A strategy for promoting γ-glutamyltransferase activity and enzymatic synthesis of S-allyl-(L)-cysteine in aged garlic via high hydrostatic pressure pretreatments

Abstract

S-allyl-(L)-cysteine (SAC) is a bioactive compound within garlic. Its level is low since SAC formation is impeded by the cellular structure of garlic. This study investigates the effect of high hydrostatic pressure (HHP) pretreatment on SAC formation in garlic aged at 40 °C for 10 days. Results showed that HHP could enhance γ-glutamyltransferase (γ-GTP) activity, damage the cellular structure of garlic and increase SAC content in aged garlic by about 7–10 times, depending on the processing parameters. HHP processing at 300 MPa for 15 min provided the optimal conditions for enhancing γ-GTP activity (45%) and promoting SAC formation (from 0.51 ± 0.01 to 5.60 ± 0.22 mg/g dry weight). It was also found that HHP could induce the greening and browning of aged garlic. As such, we consider that HHP technology is a promising technique to produce aged black garlic products with higher amounts of bioactive compounds.