Mal J Nutr 21(2): 255 - 262, 2015

Retention of Ascorbic Acid and Major Mineral Contents in Water Spinach and Chinese Kale after Three Different Cooking Methods
Chin WK & Marina AM*

ABSTRACT

Introduction: The water spinach (Ipomoea aquatica) and Chinese kale (Brassica oleracea L. var. alboglabra) are popular in Malaysia, relatively cheap and rich sources of vitamins, dietary fibre and minerals. A study was conducted to determine the retention of ascorbic acid (vitamin C) and major minerals (zinc, iron and copper) in water spinach and Chinese kale after boiling, stir-frying and steaming.
Methods: Ascorbic acid was determined using potassium iodate titration method. Major mineral contents were determined using atomic absorption spectroscopy.
Results:The results showed that stir-frying retained the highest ascorbic acid level in both water spinach (64.4%) and Chinese kale (85.9 %). Zinc showed maximum retention in boiled water spinach (103.6%) while stir-fried Chinese kale retained the highest content of zinc (88.8 %). The retention of iron level in water spinach ranged from 49.1 to 101.3% while that in Chinese kale was from 42.5 to 117.5%. The highest retention of copper was obtained in steamed water spinach (93.6%) and boiled Chinese kale (106.3%).
Conclusion: Stir-frying is the best cooking method to retain ascorbic acid in water spinach and Chinese kale while zinc, iron, and copper retention in both vegetables varied depending on the type of cooking. These findings could be part of consumer education on methods of food preparation for optimum nutrient retention.

Keywords: Boiled, stir-fried and steamed vegetables, Brassica oleracea L. var. alboglabra, Ipomoea aquatica

Download full article

March 1995, Vol1 No.1
September 1995, Vol1 No.2
March 1996, Vol2 No.1
September 1996, Vol2 No.2
March 1997, Vol3 No.1
September 1997, Vol3 No.2
December 1998, Vol4 No.1&2
December 1999, Vol5 No.1&2
March 2000, Vol6 No.1
September 2000, Vol6 No.2
Mar/Sept 2001, Vol7 No.1&2
March 2002, Vol8, No.1
September 2002, Vol8, No.2
March 2003, Vol9 No.1
September 2003, Vol9 No.2
March 2004, Vol10 No.1
September 2004, Vol10 No. 2
2005, Vol 11 No.1
2005, Vo l11 No.2
2006, Vol 12 No.1
2006, Vol 12 No.2
2007, Vol 13 No.1
2007, Vol 13 No.2
March 2008, Vol 14 No.1
2008, Vol 14 No.2
2009, Vol 15 No.1
2009, Vol 15 No.2
2010, Vol 16(1)

2010, Vol 16(2)

2010, Vol 16(3)

2011, Vol 17(1)

2011, Vol 17(2)

2011, Vol 17(3)

2012, Vol 18(1)

2012, Vol 18(2)

2012, Vol 18(3)

2013, Vol 19(1)

2013, Vol 19(2)

2013, Vol 19(3)

2014, Vol 20(1)

2014, Vol 20(2)

2014, Vol 20(3)

2015, Vol 21(1)

2015, Vol 21(2)

2015, Vol 21(3)

2016, Vol 22(1)

2016, Vol 22(2)

2016, Vol 22 Supplement

2016, Vol 22(3)

2017, Vol 23(1)

2017, Vol 23(2)