Non-conventional osmotic solutes (honey and glycerol) improve mass transfer and extend shelf life of hot-air dried red carrots: Kinetics, quality, bioactivity, microstructure, and storage stability

摘要

The effect of solutes (sucrose, honey and glycerol) on mass transfer kinetics, physico-chemical and biological quality, and shelf life of red carrot slices (RCSs) obtained by hot-air drying at 60 degrees C/6-8 h was studied. RCSs were osmosed for 24 h in sucrose (S), sucrose + honey (SH), honey (H) and sucrose + glycerol (SGL) before drying. Honey and glycerol enhanced the water loss (WL) and solute gain (SG), giving higher values for Peleg's model constants (k(1), WL = 6.9 and 6.5, for H and SGL, respectively; k(1), SG = 92.8 and 73.5, for H and SGL, respectively). Decreased viscosity of osmotic solutions corresponded with the solute effect on WL and SG, reaching equilibrium after 16 h. Different quality parameters were significantly affected by the solute type and storage time (P < 0.05). Higher beta-carotene content (7.82 g/100 g) and antioxidant activity (35.9%) values were found in honey-treated carrots. Higher SG might result in improved color parameters and least physical damage as revealed through SEM images in honey and glycerol-treated carrots. The lowest yeast and mould count (0.52 log CFU/g) was observed in SGL treatment after 5 months of storage.