Evaluation of the efficiency of various folic acid microencapsulation techniques for rice vermicelli (Khanom Jeen) fortification

Abstract

This study evaluated the efficiency of various folic acid microencapsulation techniques, such as gel particle (GP), coacervation (CC), and spray drying (SD), for fortification of rice vermicelli. Of the microcapsules, the GP capsules were rough and 13 % soluble in acid solutions; the CC capsules formed spontaneously and were water-soluble for 120 min; and the SD capsules had spherical shape and the fastest acid solubility. The different microcapsule types had different levels of folic acid loss. CC capsules dissolved in water within 120 min, whereas GP and SD capsules were water-insoluble. SD capsules had the lowest moisture content, water activity, pH, and total acidity. For rice vermicelli fortification 300 µg of SD encapsulate per 100 g of flour. The analysis of fortified rice vermicelli included water content, folic acid, pH, total acid, sensory evaluation by drying, high performance liquid chromatography (HPLC), pH meter, titration respectively, and sensory testing. In the mixing, extrusion, and first and second washing steps, the wet weight basis of 100 g folic acid SD was 342.02, 470.67, 530.07, and 546.25 µg, the acidity was 3.96, 4.09, 4.12, and 4.17, respectively; the total acid was 0.11 %, 0.07 %, 0.07 %, and 0.07 %, respectively; and the loss of folic acid during the processing in each step was 38 %, 55 %, and 60 %. The sensory test results among groups were not significantly different (p > 0.05). In conclusion, SD was the most suitable technique for folic acid microencapsulation in rice vermicelli because SD microcapsules were acid-soluble but water-insoluble, thus preventing the loss of folic acid during processing.