Study On Processing Technology Of Jujube Jam

Zizyphus Jujuba Mill is one of the characteristic fruits in China. In recent years, Chinese jujube cultivated area and production increased substanitialy. The main production is dried jujube which is dried by the natural technology and hot air drying, but this process severely losses a lot of nutrients. There are also jujube chips, candied dates, sesame seeds dates and so on. The processing and utilization of jujube is still at the primary stage. Processing jam is an effective way to enrich jujube product categories and process jujube deeply. Now, dried jujube is the main raw material to jam, to optimizated the processes and formulations of the jam by the sensory quality.In this study, fresh jujube, candy heart jujube and dried jujube which came from the same species were used as raw marterial, first of all, the single-factor test was used to evaluate the way and time of jujube softening, then to determine the best jujube softening way and time by the loss of total sugar content, flavonoids content, total phenol content and Vc content after softening and beating results of jujube.at last, study to determine the better processing and formulations of the jujube jam which used different red dates as raw materials by total sugar content, flavonoids content, total phenol content, Vc content and sensory quality of the jam. Meanwhile, comparing the nutritional quality and sensory quality of the jam which use different red dates as raw materials to determine the best raw materials for the jujube jam.Conclusions:1. The best jujube softening way and time:the hot steam softening is better than boiled softening. The best softening time for the fresh jujube and candy hearts dates is13min, dried jujube is12min. The hot steam softening can make the total sugar preservation rate increased by12.25%～45.84%, make the total phenol preservation rate increased by1.36%～7.11%and make the total Vc preservation rate increased by5.29%～29.76%than the boiled softening, but the flavonoid content is almost the same.2. The best formulations:(1) Fresh jujube:jujube plup400g, sugar120g, citric acid0.8g, boiled15min.(2) Sugar heart jujube:jujube plup400g, sugar75g, citric acid0.6g, boiled18min.(3) Dried red dates:jujube plup400g, sugar100g, citric acid1g, boiled12min.3. The analysis shows that the jam used candy heart dates as raw materials is better than the other two, it has better nutritional quality and sensory quality. 4.The process of jam used the candy heart red dates as raw materials: The red datesâ†'selectionâ†'washingâ†'hot steam softening for13minâ†'peeled to the core by handsâ†'add the same quantity water to beat for3minâ†'brewed18min while stirring, adding the sugar and citric acidâ†'seal the can when it is hotâ†'hot steam sterilization20minâ†'coolingâ†'finished product.The major nutrient content of the jam:total sugar42.83%, the flavonoids261.21mg/100g, total phenols10.69mg/g, Vc28.18mg/100g, total acid0.66g/100g, soluble solids44.96%, solid-acid ratio67.92. Sensory quality as follows:reddish brown, natural translucent; delicate taste;rich red dates flavor; jam body uniform, smear good, no sugar crystallization, no juice precipitation, no impurity.