The effect of maceration time and temperature on total phenolic compound and antioxidant activities of alpinia galanga’s extract
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Date
2019-06
Authors
Chin, Jing Yi
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Abstract
Alpinia galanga is a popular culinary ingredient as well as medicinal herb due to its total phenolic content and antioxidant capability. In this research, phenolic compound of A. galanga was extracted using maceration technique with ethanol solvent at a liquid solid ratio of 20 ml/g. Effect of maceration time, temperature and different plant parts (leaves and stems) on total phenolic compound and antioxidant of A. galanga were studied using Folin-Ciocalteu assay and DPPH radical scavenging assay respectively. The effect of maceration time was varied from 1 hr to 5 hr and the highest antioxidant activity obtained for leaves and stems were at 1 hr (IC50 = 0.136 mg/ml) and 4 hr (IC50 = 0.320 mg/ml) respectively. The highest total phenolic compound was obtained from leaves at 1 hr (0.038 mg GAE/mg DW) and stems at 4 hr (0.024 mg GAE/mg DW). Maceration time however, has no significant effect on antioxidant activity and total phenolic compound of A. galanga. Maceration temperature was examined from 40ºC to 70ºC. The highest antioxidant activity was observed at 40ºC for both leaves (IC50 = 0.076 mg/ml) and stems (IC50 = 0.454 mg/ml) while the highest total phenolic compound was recorded at 70ºC for both leaves (0.034 mg GAE/mg DW) and stems (0.019 mg GAE/mg DW). The best maceration conditions, considering from the antioxidant activity, for both leaves and stems of A. galanga were found at 1 hr and 40ºC in the viewpoint of both extract quality, energy and cost efficiency. Alpinia galanga leaves possess higher total phenolic compound and antioxidant capacity than the stems, but still many times lower than the antioxidant capacity of ascorbic acid (IC50 = 0.003 mg/ml), an antioxidant standard. There is no significant correlation between TPC and antioxidant of both A. galanga leaves and stems.