Air drying of chopped chestnuts at several conditions: effect on colour and chemical characteristics of chestnut flour

Fresh chopped chestnuts were dried using a hot air convective tray dryer at different temperatures (45, 65 and 85oC) and loading densities (2.5 and 6.3 kg/m2). Drying kinetics were experimentally determined and modelled by means of Page model. Model parameters correlations with temperature and loading density were found. Dried samples were milled and chemical composition (starch, amylose, fat, fibre, proteins, sugars) and colour characteristics of the flour were determined. Total and damaged starch varied significantly with drying temperature and loading density, but not amylose content. Protein and sugars content were also influenced by drying conditions whereas no meaningful differences were observed for fibre and fat content. Lightness of flour chestnut decreased and redness increased with drying temperature. At high loading density, the thermal effects on the flour colour were less promoted