Evaluation of Vitamin C Content in Microwave‐Dried Guava (Psidium Guajava L)

Abstract

This study is carried out to evaluate the effect of different microwave powers on the quality of microwave‐dried guava in term of vitamin C degradation. The effect of microwave heating on the vitamin C content of microwave‐dried guava using three microwave power levels of 300 W, 450 W and 600 W was determined by using High‐Performance Liquid Chromatography (HPLC). All microwave‐dried guava using three different power levels fell in the desired final moisture content range which was 16.01 – 16.05 %. The percentage loss of vitamin C in the microwave‐dried guava was 6 %, 63.8% and 85.93% at 300 W, 450 W and 600 W microwave power levels respectively. The vitamin C content of the microwave‐dried guava decreased with the increase of microwave power level. Microwave‐dried guava using 300 W power level shown the highest vitamin C content with a peak area of 691909 μV while drying using 600 W power level gave the least vitamin C content with a peak area of 103555 μV. Vitamin C is easily destroyed by the excessive heat and water, as well as exposure to air. For retention of vitamin C in dried fruit, it is recommended to apply lower microwave power level in fruit drying. Therefore, the optimum microwave power level for better quality microwave‐dried guava production assessed is 300 W.