Nutritional values and antioxidant activities of organically grown vegetables

Law, Pooi San (2012) Nutritional values and antioxidant activities of organically grown vegetables. Universiti Malaysia Sabah. (Unpublished)

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Abstract

The study was conducted to determine the nutrient composition and antioxidant activities of low land vegetables, which are organically grown. Leafy green mustard (Brassica juncea), Chinese kale (Brassica alboglaba), and fruit type vegetable on okra (Abelmoschus esculentus) and long bean (Vigna unguiculata subsp. sesquipedalis) were obtained from selected organic farms registered under Organic Scheme Malaysia. Proximate composition was determined by AOAC method, while total phenolic content were estimated by Folin-Ciocalteu reagent, and the antioxidant activities were measured by l,l-diphenyl-2-picrylhydrazyl CDPPH) radical method, Ferric reducing antioxidant power (FRAP) assay, β- carotene bleaching (BCB) assay, and Oxygen Radical Absorbance Capacity (ORAC). The phenolic compounds responsible for the antioxidant activity were identified by High Performance Liquid Chromatography (HPLC). Results show there was no significant different (p>0.05) in macronutrients content between conventionally and organically grown vegetables. However, the protein content of the conventionally grown vegetables was higher than their organic counterpart, with the highest found in kale (2.24 g/100g FW). The antioxidant activities as determined by 4 assays were found higher in organically grown vegetables, especially in leafy greens with organic mustard has the highest DPPH scavenging activities (25.03%) and ORAC value (29.94 µmol Trolox/g). Organic vegetables were found to have a significantly (p<0.05) higher phenolic compounds that are responsible for the antioxidant activity in particularly quercetin and catechin. The phenolic content was strongly correlated (Rz>0.7) with DPPH and FRAP assay. In conclusion, the basic nutrients of the organically grown vegetables do not seem to be superior to their conventional counterparts. However, the antioxidant activity and the presence of phenolic compounds were found much higher in the organically grown vegetables.

Item Type: Academic Exercise
Uncontrolled Keywords: low land vegetable, AOAC method, antioxidant activity, phenolic compound, organic
Subjects: T Technology > TX Home economics > Nutrition. Foods and food supply
Divisions: SCHOOL > School of Food Science and Nutrition
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 24 Dec 2013 03:11
Last Modified: 10 Oct 2017 06:17
URI: http://eprints.ums.edu.my/id/eprint/7862

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