The Investigation of Different Extraction Solvents for Globe Amaranth (Gomphrena Globosa)

Chin, Natasha Si Ying (2020) The Investigation of Different Extraction Solvents for Globe Amaranth (Gomphrena Globosa). Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Globe Amaranth (Gomphrena Globosa) is a type of herb that is high in phytochemical compounds and in antioxidants such as sterols, triterpenoid, tannins, phenols and flavonoids. The aim of this study was to determine and compare the antioxidant activities using different solvents to extract from the petals of the herb. The colour stability of the petals was also determined using colorimeter to determine the total colour difference before and after heating. The antioxidant tests were determined by using DPPH scavenging activity, total flavonoid content (TFC), total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) tests. It was shown that using distilled water to extract from the petals had higher antioxidant activity. Distilled water had exhibited the highest antioxidant activity compared to Fifty Percent and Hundred Percent in terms of DPPH, TFC, TPC and FRAP. Distilled water had radical scavenging activity of 69.582%, 7.398 mg QE per g of DW, 8.864 mg GAE per g of DW, 17.437 mg ferrous equivalent per g of DW. There were significant differences in antioxidant activity (p <0.05) between different solvents. Besides that, using hundred percent of methanol to extract had a lower colour difference at higher temperature compared to using distilled water and fifty percent methanol. Therefore, petals from Globe Amaranth can be used as food additive for pigmentation in low acid beverages. Besides that, the petals contain high antioxidant activity that can be used in functional ingredients in food product due to its high natural antioxidants. In future studies, Globe Amaranth will be analysed for more of its antioxidant properties using different methods of extraction.