Effect of processing on β-carotene retention in crude palm oil and its products

Abstract

Crude palm oil ( Elaeis guineensis) can serve as a promising source of β-carotene in developing countries where vitamin A deficiency is prevalent, apart from fulfilling other functions of an edible oil. Non-aqueous reverse phase HPLC analysis with a UV-Vis detector at 450 nm was carried out to estimate the amount of β-carotene in crude palm oil (CPO) produced in India. Isocratic elution with acetonitrile/methanol/dichloromethane (60%/35%/5%) at 1·5 ml/min on a 25 cm C 18 column eluted β-carotene at 14·5 min. β-Carotene content was estimated to be around 370 ppm, which amounts to about 70% of the total carotenoids (540 ppm—estimated spectrophotometrically at 450 nm E 1 cm 1% = 2500). Sensitivity and accuracy of the method was observed to be high as indicated by the standard graph of β-carotene and recovery of standard added to sample (100%). Effect of different cooking methods like baking, seasoning, deep frying and shallow frying on retention of β-carotene was studied and it was observed that 70–88% of it was retained in the cooked foods. Repeated deep frying, using the oil five times consecutively, resulted in a total loss of β-carotene by the fourth frying stage itself and alteration of its organoleptic, physical and chemical properties. Hence, CPO may be suitable for single frying operations only or for preparations which involve a short heating time and completely take up the oil into the cooked product, e.g. ‘Cake’, ‘Upma’, ‘Kichidi’, ‘Suji halwa’. Probably ‘Suji halwa’ can be selected as an ideal choice for vitamin A supplementation to vulnerable children because it is well accepted, works out to be cheap per RDA serving and it retains 70% of its β-carotene after cooking.