Application of ohmic heating/vacuum impregnation treatments and air drying to develop an apple snack enriched in folic acid

The changes of lifestyle and eating habits of consumers have induced a growth in the demand for functional food. The aim of this work was to study the incorporation of folic acid into apple slices by using ohmic heating (OH) and vacuum impregnation (VI) at 30, 40 and 50°C and air drying at 50, 60 and 70°C to obtain an apple snack that is rich in folic acid. The kinetic impregnation of folic acid, texture and color were evaluated. The impregnated samples (VI) at 40°C and vacuum-impregnated samples with ohmic heating (VI/OH) at 50°C presented a high content of folic acid, whereas the samples air dried at 60°C presented an important retention of folic acid. The lowest loss of firmness and color was obtained with the VI/OH treatment at 50°C with drying at 60°C. Therefore, the VI/OH treatment at 50°C followed by drying at 60°C was determined to be the best process for creating dehydrated apple slices that are rich in folic acid.