Effects Of Different Drying Methods On The Quality Of Jujube(Chaoyang Dapingding)

Jujube(Chaoyang Dapingding)is well known locally for its sweetness and sourness,unique flavor and delicious taste.However,with the year-on-year increase in production,a large number of large flat-top dates are unsaleable.Provide a high-quality,low-energy processing technology for the processing of jujube(Chaoyang Dapingding)dried products,and provide a direction for the utilization of jujube(Chaoyang Dapingding)resources and byproducts.In this paper,the four quality inspections of hardness,brittleness,color difference,and moisture content are used as output values.The single-factor test,Box-Behnken test,and Central Composite test are used to improve the processing drying conditions,and three ternaries of three different drying methods are obtained.The quadratic linear regression equation gives the best drying conditions for three different drying methods.Then the quality comparison of jujube(Dapingding)prepared by three different drying methods was conducted,and the in vitro antioxidant activity was measured.The results show:1.The best conditions of hot air drying technology for jujube(Dapingding)are: drying time 10.4h,drying temperature 53.6 ℃,material thickness 5.4mm,hardness 89.1723 N,brittleness 6.8511,chromatic aberration 44.2601,moisture content 5.1042%.After verification,the model is accurate and reliable.2.The best microwave drying conditions of Dapingding jujube: microwave temperature49.9 ℃,microwave time 1104.5s,microwave gear 3,material thickness 5.7mm,hardness77.4623 N,brittleness 17.1323,chromatic aberration 46.5605,moisture content 1.8541%.After verification,the model is accurate and reliable.3.The optimum conditions of the expanded drying process of jujube(Dapingding)were as follows: pre drying 36.0%,material thickness 6mm,evacuation time 3h,expansion temperature 84.6 ℃,hardness 99.4091 n,brittleness 19.21,chromatic aberration 36.475,moisture content 4.7406%.After verification,the model is accurate and reliable.4.Considering the water content,hardness,brittleness,color,rehydration,total polyphenol content,flavonoid content,reducing sugar content,total sugar content and total acid content of jujube(Dapingding),it is found that the expansion drying with variable temperature and pressure difference is more important than microwave drying and hot air drying.5.The results showed that DPPH free radical scavenging rate and hydroxyl free radicalscavenging rate of three different drying methods of jujube(Dapingding)were almost the same,and its reducing capacity,superoxide anion scavenging capacity and ABTS antioxidant capacity all showed as follows: expansion drying with variable temperature and pressure difference > microwave drying > hot air drying.