Evaluation Of Fresh Jujube Power Made By Different Drying Methods And Development Of A Solid Hot Drink

The jujube is fruit of jujube which is classified Rhamnus Linn.Jujube is not only delicious but also has a high nutritional value and economic value.2007 statistics show that Chinese jujube cultivation area is about 16 million hectares and fresh jujube production is about 20 million tons.But less than 30%of the total production of fresh jujube is used for processing.About 80～90%of fresh jujube used for processing is made into dried dates,but this processing of fresh jujube exists a lot of problems such as vitamin loss,high energy consumption,Low value-added and so on.this processing can not exploited defective jujube resulted in a waste of resources and resulted in the ability to withstand natural disasters of jujube farming can not be improved.so,the jujube industry economic benefits can not be fully.How to process fresh jujube has become the bottleneck problem of Chinese jujube industry.In this study,fresh jujube is made into power through different pre-treatment ways and different drying methods(hot air drying,vacuum freeze-drying,microwave drying and vacuum drying),then the best way to dry is determined after comparing the power characteristics,composition and antioxidant ingredient which made by different drying methods.And finally to manufacture a fresh jujube pulp solid breakfast hot drink under the appropriate deployment test and stability test,which can also provide a reference for the deep processing of fresh jujube.The following conclusions can be drawn in this study:(1)The jujube powder which comes from fresh jujube(peeled and pitted)without pre-treatment has a strong ability to absorb moisture and a poor dispersing ability.In order to alleviate these drawbacks,fresh jujube should be pretreated before made into power and the conclusion obtained by experiment is that the best water addtion is 60%of fresh dates’(peeled and pitted)weight.(2)All hot air drying,vacuum freeze drying,microwave drying and vacuum drying could make moisture of fresh jujube powder less than 8%.The Jujube powder obtained by microwave drying has a poor ability to absorb moisture,good dispersion(3.83±1.19 s)and good mobility(3.42 ± 1.17 s);this powder suits as raw materials for reconstituted drinks.(3)Acid,phenols will loss because fresh jujube is pretreated,but we can make a conclusion that the jujube powder obtained by vacuum freeze drying or microwave drying both have either equal or higher content of Vc,total flavonoids and proanthocyanidins compared with the Jujube powder without pretreatment.this conclusion shows that drying methods play a crucial role in maintaining components and antioxidant activity of fresh jujube powder.(4)The best way to dry Jujube has became obviously comparing the.power characteristics,composition and antioxidant ingredient which made by different pre-treatment ways and different drying methods.the jujube power finally obtained after several steps as follow:pretreating the fresh jujube peeled the peel and core with water(60%of the quality of fresh jujube),and separating to obtain pulp,and then drying it with microwave method.(5)Seasoning test and stability test indicated that hot drinks can not meet the stability requirements using a single stabilizer.The optimized results is addition 0.10 g of A,0.10 g of B,0.05 g of C,0.02 g of D and 1.2 g of X,1.0 mg of Y to hot water(100 ml,80℃)at the same time.