The present study evaluated the incorporation of 5, 7.5, and 10% of Riesling skin flour (RSF) and Tannat skin flour (TSF) as wheat flour replacement in muffins. The flour was evaluated for gluten content and Alveograph parameters. The finished products were evaluated for chemical composition and technological properties, and a sensory analysis was performed. All samples presented higher dietary fiber content than wheat flour, and this was mainly in the form of soluble dietary fiber. The inclusion of grape skin flour decreased the lightness of the flour and increased the lightness values (L*) of the muffin crumbs and crusts. The hardness of the muffins that incorporated RSF and TSF muffins increased as the percentage of the skin flour increased. There was a decrease in the cohesiveness value as the skin flour percentage increased. Consumers did not perceive the levels of substitution. The results of the sensory analysis indicated that grape skin can be added to the ingredients of muffins without changing the color, taste, flavor, texture, and overall acceptability of the final product.

The objectives of this study were to characterize zein fibers and capsules prepared by electrospinning and electrospraying techniques, respectively, and then use them to encapsulate folic acid. Folic acid containing fibers and capsules (0.5, 1.0, and 1.5%, w/v) were submitted to thermal treatment (100, 140, and 180 °C) and ultraviolet A light (UVA) irradiation to evaluate the resistance of folic acid. Zein fibers and capsules containing folic acid showed high encapsulation efficiency (>80%). Unencapsulated folic acid showed a reduction in folic acid content from 17.17 μg/mL to 5.44 μg/mL (approximately 70%) when exposed to 180 °C. Photodegradation of unencapsulated folic acid lowered its concentration from 17.17 μg/mL to 12.58 μg/mL (~26% of reduction), when exposed for 1 h to UVA irradiation. However, folic acid concentration when encapsulated in fibers (1.5%) was maintained or only slightly reduced from 9.73 μg/mg to 8.88 μg/mg after thermal treatment at 180 °C. The capsules containing 1.5% of folic acid also presented a slight reduction in folic acid concentration from 8.84 μg/mg to 7.88 μg/mg when exposed to 24 h of UVA irradiation. Zein fibers and capsules containing folic acid present promising characteristics for application in foods that require thermal processing or exposure to irradiation.