High pressure impregnation of oil in water emulsions into selected fruits: A novel approach to fortify plant-based biomaterials by lipophilic compounds

Abstract

High pressure impregnation (HPI) at 100 MPa was evaluated as a means of enrichment of fruit tissue with model oil in water emulsions. Coconut oil + polysorbate (Tween 80) emulsion premix were prepared at different mass proportions [oil/(oil + emulsifier)] = 1/2n for n = 1–4), and mixed water (20:80, emulsion:water) (Emulsions I to IV) prior to impregnation. The emulsion stability for the HPI was studied by dynamic rheology, pH change, and particle size distribution analysis. Cube shaped samples (1.2 cm × 1.2 cm x 1.2 cm) were cut from apple, strawberry, pear, Asian pear, and melon as fruit tissues. The mass transfer during the HPI for up to 20 min (for emulsion-I) followed a pseudo-second order kinetics model in all fruits. The highest and the lowest final mass intake belonged to apple (18 g/100 g) and strawberry (6 g/100 g), respectively. The HPI of emulsions with different premix combinations (emulsions I to IV) was evaluated with a 20-min treatment time for all fruits. Results demonstrated that the final mass intake increased with the oil content and decreased simultaneously with an increase in the emulsifier content. Light microscopy results demonstrated the distribution of oil droplets within the water phase into the intercellular space.