Effect of heating time on the quality and antioxidant activity of Jerusalem artichoke tea

Abstract

This study aimed to evaluate the physicochemical characteristics, bioactive compound component content, and antioxidant activity of Jerusalem artichoke tea. The Jerusalem artichoke was dried at 70°C for 5 h, then roasted in the oven for 2, 4, and 6 min, respectively. The control group had a moisture content of 11.92%, whereas the sample heated in the oven for 2-6 min had a rapidly declining moisture content. Oven-heated samples had higher levels of crude protein and fat than the control samples. Longer heating periods reduced the pH of the Jerusalem artichoke while increasing the sugar content and turbidity of the tea. The brightness of the tea decreased as the heating time increased, while the redness, yellowness, and browning index increased. Compared to the control group, the total polyphenols and flavonoids eluted in tea increased 1.04 to 4.34 times and 1.09 to 2.70 times, respectively, with the heating time of the Jerusalem artichoke. The elution of antioxidant substances and the antioxidant activity of the tea also was also increased with the heating duration. Therefore, the results revealed that the antioxidant content and activity of Jerusalem artichoke tea are highest when heated for approximately 6 min after removing any excess moisture.