Research on Production Technology of Low-temperature Superfine Grinding Jujube

Dongxia Yang,Zhang Tianmei,Mingzhe Qu,Fan Lihan

doi:10.19026/ajfst.12.2969

Abstract

At present, the drying methods for jujube powder consists of powder process after jujube dryness and powder process after concentrating jujube juice. In order to obtain jujube powder with small particle size, good rehydration, higher VC content and better color, this study proposes to adopt different drying methods, namely, first carry out preliminary cooling against the jujube pieces at low temperature before drying and then take the secondary cooling method during the drying process, in order to make jujube pieces brittle and get superfine jujube powder. After comparing the jujube powder prepared through ordinary drying methods and the drying method of low-temperature superfine grinding, results show that in terms of physical properties, the latter may get smaller particle size, lighten color and better tastes of jujube powder particle than the former; in terms of nutrient content, the latter has relatively higher reducing sugar and total sugar contents. Therefore, the second drying method is superior to the first one. In this context, this study analyzes the structure, drying principle and force required by the drying process of drying equipment of low-temperature superfine grinding system. In the design process of grinding system, this study attempts to separate the nucleation and growth process of powder particles into different parts for drying equipment, in order to effectively control the particle size of jujube powder, reduce the particle agglomeration when collecting the jujube powder and improve the quality and uniformity of jujube powder.

Highlights

Red jujube is a fruit of endemic to China, has a high nutritional value and medicinal value, and has a reputation of "king of the fruits"
At present red jujube selling limited to domestic, products mainly are dried jujubes, some red jujubes are processed into candied jujube, jujube juice and jujube wine, but mostly for primary processing products, form is single and the added value is low (Xu et al, 2012; Zhou et al, 2013)
Physical characteristics of jujube powder under different drying methods: Effects on jujube powder rehydration and particle size: Jujube powder prepared by low-temperature the jujube powder prepared by ordinary high-speed drying method, yet the reducing sugar and total sugar contents of jujube powder produced by drying method are lower than fresh jujube, because prepared by ordinary high-speed drying method has lower reducing sugar and total sugar contents, because there are lots of heat during the drying process, causing serious Maillard reaction of heat and more consumption of sugar

Summary

INTRODUCTION

Red jujube is a fruit of endemic to China, has a high nutritional value and medicinal value, and has a reputation of "king of the fruits". At present red jujube selling limited to domestic, products mainly are dried jujubes, some red jujubes are processed into candied jujube, jujube juice and jujube wine, but mostly for primary processing products, form is single and the added value is low (Xu et al, 2012; Zhou et al, 2013). According to the present situation of Chinese jujube industry development, develop the diversified products and make the comprehensive utilization of jujube resources have important scientific significance and application value to the development of red jujube industry. In this study, used liquid nitrogen cooling technology to crush seedless red jujubes under cryogenic vacuum freezing conditions, produced ultra fine particles original jujubes powder without any additives and provide reference basis for the research and industrial production of jujubes powder processing technology

MATERIALS AND METHODS

AND DISCUSSION

Determination Method for Fruits and Vegetable