Sorption characteristics of full-fatted grape seeds flour of Bulgarian origin

Abstract We were experimentally obtained the sorption characteristics of full-fatted grape seeds flour (FGSF) of different grape varieties locally grown in Bulgaria. The scientific research was investigated at temperature - 10 °C, 25 °C and 40 °C and water activity within the range from 11% to 90%. We were selected the modified Oswin and Chung-Pfost models suitable for describing the adsorption and desorption isotherms. Monolayer moisture content of FGSF is calculated – from 2.48% to 4.59%. Antioxidant capacity was proven through DPPH (578.42 ± 23.06 mM TE/g extract), ABTS (1352.12 ± 144.31 mM TE/g extract), FRAP (966.45 ± 127.31 mM TE/g extract) and CUPRAC (1789.44 ± 180.11 mM TE/g extract). The values are also shown in mM TE/g flour (578.42 ± 23.06 mM TE/g flour); (1352.12 ± 144.31 mM TE/g flour); (966.45 ± 127.31 mM TE/g flour) and (1789.44 ± 180.11 mM TE/g flour), respectively. Furthermore, we evaluated the changes in moisture content, microbiological load and particle size distribution during short-term storage study for a period of three months. FGSF were packed in plastic bags under the conditions - temperature 18 °C÷25 °C and relative air humidity 45% ÷ 55%.