Preparation Of Loquat Fruit Crisp Based On Vacuum Freeze Drying Technology

In this study,fresh loquat fruit was used as a test material,and the rehydration ratio of freeze-dried loquat fruit crisp,physiological and biochemical indexes and sensory morphology were used as evaluation indexes to study the optimum eutectic point,packing thickness,pulp beating time,pulp water quantity,temperature of sublimation drying section,sublimation drying period and drying section temperature of the best fresh loquat fruit pulp.The combination of process parameters is expected to lay a solid foundation for the subsequent production of loquat fruit crisp.The main results are as follows:1.The eutectic point of loquat fruit pulp: the temperature of the eutectic point of the loquat fruit pulp is-15 ?.At this temperature,the moisture in the loquat fruit pulp will be completely frozen into ice,and the resistance value will suddenly change to almost infinity.2.The best packaging thickness of loquat fruit pulp: the optimum packaging thickness of loquat fruit pulp is 9mm,and the loquat fruit crisp is prepared by this thickness.The rehydration ratio,total sugar content,total acid content,vitamin C content and sensory index are 1.97,5.5281g/100 g,0.5006g/100 g,3.0548mg/100 g,taste flavor is78.84,the crisp degree is 78.72,the color is 91.62,and the appearance is 90.16,respectively.3.The beating time of loquat fruit pulp: the best beating time of loquat fruit pulp is60 s,and the loquat fruit crisp prepared by this pulp beating time,the rehydration ratio,the total sugar content,the total acid content,the vitamin C content and the sensory indexes are 3.30,5.7642g/100 g,0.5533g/100 g,2.9702mg/100 g,taste flavor is 92.11,the crisp degree is 87.94,the color is 85.14,and the appearance is 87.55,respectively4.Loquat fruit pulp adding water: the optimum adding amount of loquat fruit pulp is150 ml per 780 g fresh fruit pulp,and the loquat fruit crisp prepared by the addition of loquat fruit pulp,the rehydration ratio,total sugar content,total acid content,vitamin C content and sensory index are :3.42,5.7392g/100 g,0.5587g/ 100 g,3.0957mg/100 g,taste flavor is 90.93,the crisp degree is 91.68,the color is 89.41,and the appearance is 89.76,respectively.5.The combination of the temperature of sublimation drying section,the time of sublimation drying and the analysis of the temperature of the drying section: the temperature of the sublimation drying section is 15?,the time of sublimation drying is35 h,and the temperature of the analytical drying section is 45?.The loquat fruit crisp prepared using these parameters had the rehydration ratio,the total content of sugar,the total acid content,the content of vitamin C,and the sensory index of 2.48,5.1806g/100 g,0.5168g/100 g,3.1915mg/100 g,taste flavor is 91.88,the crisp degree is 92.03,the color is93.24,the appearance is 93.62,respectively.