Production and application of freeze dried biocomposite coating powders from sunflower oil and soy protein or whey protein isolates.

Innovative biocomposite coating powders based on soy protein isolate or whey protein isolate, both containing sunflower oil (SO) were fabricated by freeze drying technique. The influences of concentration of SO and using different protein isolate types on the physicochemical, thermal and morphological properties of the powders were investigated. The Fourier transform infrared spectroscopy and thermal analysis revealed that SO interacted with protein isolates through hydrogen bonding resulted a strong network structure of the powders. It was found that amorphous structure and morphology of the powders was not significantly influenced by oil addition. Moisture content and water activity values of SPI powders were found higher than those of WPI. All powders were wettable, and solubility values were in the range of 91-99%. Preservative-free powders were reconstituted and applied to coat sliced cakes, a bakery product. Coating application showed effective protection on textural structure of cake by high moisture preservation ability.