Fibra alimentar a partir de casca de uva: desenvolvimento e incorporação em bolos tipo muffin

Abstract

In the wine industry are generated large quantities of solid waste, such as grape pomace, which are discarded or underutilized. However, represent alternative nutrient sources, as significant levels of dietary fiber. The study aimed to evaluate the chemical composition and technological properties of grape pomace skins, before and after dietary fiber concentration. In addition, the aim was to evaluate the effect of their inclusion in muffins, in nutritional, technological and sensory parameters. The skins of Cabernet Sauvignon, Chardonnay, Marselan, Merlot, Pinotage, Pinot Noir, Riesling, Shiraz and Tannat cultivars collected in Rio Grande do Sul wineries, in the 2013/2014 harvest were analyzed for dry matter (DM), ash, protein, lipids, dietary fiber, binding cations capacity, fat adsorption capacity and water retention capacity. It was evaluated the technological properties of flour containing 5, 7.5 and 10% Riesling or Tannat grape skin flour and developed rich in fiber muffins, which were subjected to sensory and nutritionally through their chemical composition and technologically, the color evaluation and texture. It was verified high dietary fiber content in the skins, which ranged from 37.18 to 67.95% (in DM), highlighting the insoluble fraction (31.09 to 62.34% in DM). Minerals and protein contents were relevant mainly after dietary fiber concentration, ranging from 7.63 to 18.60% and from 7.40 to 20.21% (in DM), respectively. The concentration process reduced the lipid content and increased the binding cations capacity. For the water retention and fat adsorption capacities, the levels ranged from 2.03 to 2.96 g water/g DM and 1.25 to 2.24 g oil/g DM, respectively, before the concentration; after the process, the levels remained similar. The rheological analysis revealed a decrease in the gluten strength and extensibility and tenacity increase, with the inclusion levels. The muffins formulations showed an increase in the fiber content in relation to the control formulation. Additionally, it was observed an increase in hardness and chewiness parameters and color change as the skin flour percent increased. The test formulations were satisfactory acceptability in all sensory attributes, except for Tannat formulation, which obtained the lowest means. There was a favorable purchasing intention for all formulations. This study proved that the grape skins, wine by-products, usually wasted, are highly nutritious, source of dietary fiber and its inclusion in muffins provided products with nutritional and sensory quality accepted by consumers.