The effect of particle size on the composition and the hydration, oil holding, thermal, and technological properties of grape pomace

Abstract

Grape pomace is a by-product of the beverage industry. In this study, composition, hydration, oil holding, thermal, and some technological properties, in addition to the colour values of grape pomace with particles larger than 595 μm, 298-595 μm, 150-297 μm, 149-106 μm, 75-105 μm and smaller than 74 μm were found to be different. In the sample with particles larger than 595 μm, ash, crude fat, carbohydrate content, sediment volume fraction in water and oil, pH, thermal diffusivity, and colour lightness (L) were measured higher than in the other samples. The water holding capacity, absorption index, oil holding capacity, and swelling power in oil were the highest in samples with 150-297 µm particle size. Moisture, crude protein content, solubility index, swelling power in the water, bulk and packed density, water activity, brix, refractive index, thermal conductivity, specific heat, redness (a), yellowness (b) and colour difference (∆E) properties were determined to be the highest in samples with particle sizes smaller than 74 µm.