Effect of Osmotic Method on Cell Structure and Quality of Vacuum Freeze-dried Mango

This study aimed to explore the effect of osmotic methods on the cell structure and quality of freeze-dried mango. This experiment uses jade as the raw material, mango was treated by solid osmotic (SSD) and liquid osmotic (LOD) at 20 and 30 ℃, and then vacuum freeze-dried. By measuring the soluble solids and cell morphology of fresh mango samples after osmosis treatment, and analyzing the changes of elastic modulus, porosity, cell wall structure, color and V_C, total phenols, and β-carotene retention index of freeze-dried mangoes. The results showed that the increasing of soluble solids in solid osmotic mango was higher than that in liquid osmotic. There was no significant difference between the cell morphology of liquid osmotic mango and fresh sample (CK). The content of soluble solids and the shrinkage degree of cell morphology increased with the increasing of sucrose, the solid osmotic reduced the intercellular porosity and increased the elastic modulus of mango. Moreover, results of infrared spectroscopy showed that the stretching vibration absorption peak of O-H increased with the increasing of sucrose content. Low sucrose solid osmotic helps to maintain the color of mango. The retention rates of V_C and total phenol in solid osmotic were higher than those in liquid osmotic at ambient temperature of 20 and 30 ℃, and the highest retention rates of SSD20 V_C and total phenol in solid state infiltration were 37.75% and 33.37%, respectively. The retention rate of β-carotene in vacuum freeze-dried mango SSD20 treated with solid osmotic treatment was higher than that of liquid osmotic treatment LOD30, but the retention rate of β-carotene decreases gradually with the increasing of sucrose supplementation in solid osmotic treatment. The results of this study showed that low sucrose solid osmotic could effectively improve the comprehensive quality of vacuum freeze-dried mango, which would provide a theoretical reference for improving the quality of dried mango products.