Effect of various cooking methods on nutritional value, antioxidant activity and bioavailability of minerals in wild vegetables (Passiflora foetida and Portulaca oleracea)

Lee, Yen Ching (2010) Effect of various cooking methods on nutritional value, antioxidant activity and bioavailability of minerals in wild vegetables (Passiflora foetida and Portulaca oleracea). Universiti Malaysia Sabah. (Unpublished)

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Abstract

The aim of this study was to investigate the effect of cooking methods on micronutrients, antioxidant activities and bioavailability of minerals in wild leafy vegetables. Two wild vegetables (P.foetida and P.oleracea) were collected in fresh and kept at 4°C: within 24 hour prior to sample preparation. The samples was then cut into small pieces (~6 cm) before subjected to blanching (70°C, 80°C and 90°C), boiling and stir frying to access their micronutrients, antioxidant potential and bioavailability of selected minerals. Results revealed a significant decrease (p<0.05) in ash, fat, protein and dietary fibre of the vegetables after cooked. The highest loss of f3-carotene and ascorbic acid was observed in P.foetida (66% and 48%) and P.oleracea (91% and 88%), after stir fried for 5 min. Blanching was found to have the least effect on the minerals content for both vegetables. Nevertheless, boiling for 15 min showed the greatest loss of potassium in P.foetida while stir fried for 5 min lead to the highest loss of calcium, magnesium, iron and zinc. The antioxidant activities of P.foetida and P.oleracea was found to be the highest after blanched at 70°C for 5 min as compared to other cooking treatments. Stir fried for 5 min caused the highest reduction of oxalate (50% and 59%), soluble oxalate (78% and 84%) and phytic add content (33% and 54%) in P.foetida and P.oleracea, respectively. On the other hand, bioavailability of minerals significantly increase (p<0.05) in the order of stir fried > boiling >blanching. The bioavailability of calcium in P. foetida (41.06%) and P. oleracea (53.64%) was the highest as compared to iron (11.46% and 14.37%) and zinc (9.66% and 14.87%) after stir fried for 5 min. Overall, cooking at high temperature and longer time tends to reduce the antioxidant activities, micronutrients and anti nutrients of P.foetida and P.oleracea.

Item Type: Academic Exercise
Uncontrolled Keywords: Micronutrients, Antioxidant activities, Wild leafy vegetables, Passiflora foetida, Portulaca oleracea
Subjects: ?? TX642-840 ??
Divisions: SCHOOL > School of Food Science and Nutrition
Depositing User: Unnamed user with email storage.bpmlib@ums.edu.my
Date Deposited: 16 Jan 2012 07:37
Last Modified: 12 Oct 2017 06:18
URI: http://eprints.ums.edu.my/id/eprint/678

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