New insights into antityrosinase capacity and polyphenols of asparagus during hydrothermal treatments

An understanding of the antityrosinase capacity and polyphenols changes during hydrothermal treatments was crucial for application of asparagus. Therefore, asparagus extract was treated at a range of 80-160 °C for 30-150 min in a high temperature reactor. The results suggested that tyrosinase inhibition rate of untreated asparagus extract was recorded as 3.26% but significantly increased to 51.22% and 50.80% after heating for 90 min at 140 °C (lnR0 of 7.21) and 160 °C (lnR0 of 8.57), respectively. The generation and degradation of polyphenols followed the pseudo-first-order kinetic model. The coumaric acid content was increased from 35.03 μg/mL to 307.66 μg/mL at lnR0 of 8.16. The degradation of rutin in asparagus extract was far less compared to that of coumaric acid. Compounds formed were determined by UPLC-Q-TOF-MS yielding main fragments at m/z 451 and 601. In conclusion, hydrothermal treatment was a feasible method for increasing the antityrosinase capacity of asparagus.