Application of gum Arabic, β-cyclodextrin, and hydroxypropyl-β-cyclodextrin to microencapsulation by molecular inclusion of grape skin extract (Vitis labrusca var. Isabel)

Abstract

Gum Arabic (GA), β-cyclodextrin (β-CD), and hydroxypropyl-β-cyclodextrin were used in different proportions to microencapsulate polyphenols obtained by aqueous extraction from a grape skin. Phenol contents of the microcapsules were evaluated for anthocyanins, flavonoids and total flavanols, antioxidant activity, color, moisture, water activity (Aw), solubility, hygroscopicity, and glass transition temperature (Tg). The microcapsules prepared with either 5% GA or a mixture of 3% GA and 2% β-CD had the highest retention of phenolic (78.9 and 67.5%, respectively), anthocyanins (35.3 and 29%, respectively) and antioxidant activity greater than 50% measured by the DPPH and CUPRAC methods. Treatment with 3% GA and 2% β-CD showed the highest retention of flavonoids (67.2%) and total flavanols (51.1%), as well as physical properties suitable for this type of product, such as Aw of 0.175, solubility greater than 90%, hygroscopicity of 17.3%, and Tg of 32.8°C, which may contribute to a greater stability of the powder. Practical applications Grape processing by-products have a great feasible commercial, and this is due at high concentrations of phenolic compounds in grape skin. It was possible to obtain inclusion complexes powder of phenolic compounds from grape skin, using cyclodextrin and its derivates in mixture with Arabic gum as carriers. This way, the stability of bioactive compounds may be improved during food processing, storage and pass through the gastrointestinal tract. In addition, it is possible to enhance solubility of phenolics compounds in aqueous dispersions. Powders obtained have antioxidant properties and potential prebiotic activity.