Production of low trans-fat margarine by partial hydrogenation of palm oil using nature-friendly and catalyst-free microwave plasma technique

Abstract

A 2.45 GHz microwave (MW) plasma furnished with a negative high voltage has been successfully utilized for partial hydrogenation of palm olein to produce low trans-fat margarine at low temperature and low pressure in the absence of a catalyst. The effects of various parameters: H2 flow rate, microwave power, reaction temperature, negative high voltage and reaction duration on the iodine value (IV) and culinary characteristics of the hydrogenated oil were investigated. The results showed the optimal parameters of 4 L-min−1 H2 flow rate, 600 W MW power, 32 °C (due to self-heating of the plasma), 60 kV negative high voltage and 4 h reaction duration, reducing the iodine value from 57.7 to 32.5 with good texture and slip melting point (SMP). The trans-fatty acid was detected by GC–MS to be 4.23%, being lower than conventional catalytic hydrogenation. This catalyst-free MW plasma hydrogenation of vegetable oil under benign conditions is a green alternative for the production of low trans-fat margarine.