Thesis (BS Food Technology) -- University of the Philippines Mindanao, 2010

Langkawas (Alpina galanga) and luyang tapul (Alpina officinarum) were evaluated for total phenolics and antioxidant activities using cold water extracts, antioxidant activities were also assessed as affected by boiling using 1, 1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Three boiling durations were investigated: 3 minutes, 5 minutes, and 7 minutes. The total phenolics of langkawas was found to be 0.89 mmol GAE/g extract while that of luyang tapul was 1.46 mmol GAE/ g extract. Evaluation of antioxidant activity of langkawas prior to boiling resulted in a value of 48.42 umol TE/ g extract while for luyang tapul, it was 135. 69 umol TE/ g extract. Upon boiling at the specified durations, langkawas exhibited the hghest increase in antioxidant activity after 5 minutes of boiling with 280.98 umol TE/ extract while luyang tapul exhibited the highest increase in antioxidant activity after boiling for 3 minutes with an activity of 286. 04 umol TE/ g extract. Results of the preliminary investigation on the total flavonoid content of the spices showed a value of 0.04 mmol CE/ g extract while for luyang tapul was 0.06 mmol CE/ g extract. Residual antioxidant activity analysis of the spices using methanol extraction showed that langkawas had 151.23 umol TE/ g extract while luyang tapul had 813 umol TE/ g extract.