Mathematical modeling and effect of drying temperature on physicochemical properties of new commercial grape "Kyoho" seeds

Grape seeds (Kyoho: Vitis labruscana), an agricultural waste with value-added potential, was investigated for the relationship between its physicochemical properties and drying temperature fitted with four thin layer drying models in a hot air oven. Experimental moisture ratio decreased with an increase in drying temperature; moreover, moisture diffusivity (D-eff) ranged from 2.69 +/- 1.82 x 10(-8) (303.15 K) to 8.68 +/- 1.25 x 10(-8) (333.15 K) m(2)/s with activation energy of 33.72 +/- 0.76 kJ/mol (R-2 = 0.9914). Logarithmic (303.15 K: R-2 = 0.9944, 333.15 K: R-2 = 1) and Henderson-Pabis (313.15 K: R-2 = 0.9611, 323.15 K: R-2 = 0.9706) models were the most suitable for predicting experimental drying curves. Drying temperature had significant (p < .001) effects on physicochemical properties of Kyoho seeds except for color (1.36 +/- 0.13 to 1.76 +/- 0.29) and oil holding capacity (0.70 +/- 0.01 to 0.94 +/- 0.02 g/g). This study demonstrated the role of drying models to develop grape seed value-added products. Practical applications The study was conducted to investigate the thin layer drying characteristics of Kyoho seeds at different drying temperatures. Moreover, the effect of drying temperature on physicochemical properties was evaluated. The proposed models should be useful to understand the behavior of drying models and predicted the effect of drying temperature on physicochemical properties. The insights gained from this study may be useful in food processing industries for designing grape seed drying equipment, which may contribute to the development of value-added products from grape seeds.