龙眼果肉干制预处理工艺的研究

Studies on Pretreated-technologies of Dried Longan Pulp

以减轻龙眼果肉干制期间的皱缩变形及褐变度为目的,通过L9(34)正交试验设计,研究不同温度、热烫时间和冷却方式对热烫处理后龙眼果肉中多酚氧化酶和过氧化物酶活性的影响,比较不同浓度配比护色液对龙眼果肉干制产品色泽和感官品质的影响,并采用正交试验设计优化工艺参数。结果表明:最佳的热烫工艺参数为热烫温度100℃、热烫时间3 min、室温冷却;0.10%抗坏血酸+0.20%柠檬酸+0.10%半胱氨酸+0.10%CaCl2的复合护色液可以保持龙眼果肉干制品的最佳品质。该工艺的实施能有效抑制龙眼果肉的褐变,使果肉在干制加工过程中保持自然色泽和良好风味,解决了产品干制后果肉皱缩变形、褐变严重、色泽差、二氧化硫残留等问题,并延长了产品保质期。

In order to reduce the shrink and browning reaction of longan pulp during drying ,the three fac-tors with three levels for L9 （34 ） orthogonal experimental design were carried out to investigate the effects of temperature,time and cooling ways on the activities of polyphenol oxidase and peroxidase in blanched longan pulp,the effects of different combinations and concentrations of sulphur-free color-protection liquid on color and sensory evaluation of dried longan pulp were compared ,then the optimized parameters were determined by orthogonal experimental design methods .The results showed that the optimum blanching temperature was 100℃,blanching time was 3 min,and cool at room temperature ,and 0.10 %vitamin C＋0.20 %citric acid＋0.10 %cysteine ＋0.10% CaCl2 can provide the optimum quality for dried longan pulp .The optimal pa-rameters of pretreated-technologies can effectively inhibit browning reaction , which result in maintaining the natural color and flavor of longan pulp during dring ,solving the problems of dried longan pulp such as shrink-ing,serious browning , poor color and residue of sulfur dioxide , and prolonging the shelf life of dried longan pulp.