New Powder Material Obtained from Spent Coffee Ground and Whey Protein; Thermal and Morphological Analysis

Currently, the food industry generates large amounts of agroindustry waste. Specifically, the coffee and cheese industry produce spent coffee ground and whey respectively. Therefore, it is important to find applications for these residues allowing the food industry to be friendly with the environment. The main goal of this research was to evaluate some morphological and thermodynamic properties of a powder product obtained by spray drying, from the mixture of Spent Coffee Ground (SCG) with Whey Concentrated (WC). The methodology includes the mixture of different combinations of SCG (4, 10 & 16%) with WC; afterward, the mixture was spray dried using an inlet temperature of 170 degrees C. The powder characterization includes: Moisture, Water Activity (A(w)), Glass Transition temperature (T-s). In addition, isothermal curves were obtained. As a result, the moisture content and A w of the powder were 3.25 +/- 0.18 and 0.252 +/- 0.01, while the bulk density was 0.495 +/- 0.10 g/cm(3), showing a significant correlation (p < 0.05) with the particle size (43.87 mu m). Such an effect was confirmed by a Scanning electron microscope. The T g values were in between 59.72 and 84.58 degrees C. Moisture-sorption isotherms were determined (17-45 degrees C) and the moisture content at the monolayer was between 0.043 and 0.086 kg of water/g dry basis, and the isosteric heat was -27.65 kJ/mol, which decreased as a function of the increase in moisture content. In general, it can be concluded that it is possible to obtain a powder, from the residues of the coffee and cheese industry; which has physical, thermal and morphological properties with high potential for application in the dairy industry.