Optimisation of corn silk tea production, and its antioxidant profile

Following COVID-19 pandemic, functional foods and beverages continue to develop,
especially those with high antioxidant activity. The functional beverage from corn silk can
be processed into brewed tea. The critical points in the making process of corn silk tea are
the drying equipment, drying temperature, and drying time. With efficient method, corn
silk tea can produce high antioxidant activity. The present work optimised the temperature
and drying method based on antioxidant activity. The results of the present work are
expected to be used in micro/small/medium enterprises (MSMEs) to produce corn silk
herbal tea. The present work used Randomised Block Design (RBD) with two factors;
drying temperatures (45, 55, and 65°C) and drying equipment (cabinet and oven) for 5 h.
The analysis carried out was antioxidant activity and profiling using LC-HRMS (liquid
chromatography high-resolution mass spectrometry) that ran in a positive (+) mode. The
processing of corn silk tea using cabinet drying at 65°C for 5 h produced antioxidant
activity of 82.00 ± 0.75%. This was higher than commercial black tea (81.71 ± 0.15%) and
commercial green tea (78.37 ± 0.43%). The analysis using LC-HRMS showed that the
corn silk tea contained betaine (N,N,N-trimethylglycine) (RT 0.928), 6-methylquinoline
(RT 4.741), hesperidin (3’,5,7-trihydroxy-4’-methoxyflavanone) (RT 302.07817),
luvangetin (10-methoxy-2,2-dimethylpyrano[3,2-g]chromen-8-one) (RT 258.08837),
embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) (RT 13.074), and eucalyptol (1,8-
cineole) (RT 13.325).