Study On The Processing Technology Of Ginger Concentrated Juice

Ginger?Zingiber officinale Rosc.?is one of the most common seasoning ingredients on people's dining tables.It has been used as a raw material for Chinese herbal medicine and food processing for thousand years.Ginger,as an important economic crop in agricultural production,has abundant germplasm resources in China,and its cultivation area,planting output,and total export volume rank first in the world.At present,ginger is mainly used for fresh food.Because the moisture content of ginger is generally above 85%,it is not resistant to storage,and it is prone to shrinkage,fibrosis and cold damage during storage.The annual loss due to improper storage is as high as 20%of the total output.It is an urgent problem for ginger industry that the effectively and rationally using ways of ginger resources is explored and the economic losses is reduced.Therefore,Jinyang ginger in Datian County was used as a raw material in this paper.The composite enzyme treatment and vacuum concentration technology were used to produce ginger concentrated juice.Moreover,the quality and rheological properties of the ginger concentrated juice were investigated.The results will provide a theoretical basis and scientific guidance for the development of new ginger products.The main research contents are as follows:?1?Ginger juice was prepared by combined enzymatic hydrolysis of cellulase and amylase.The effects of cellulase dosage,amylase dosage,enzymatic hydrolysis temperature and time on ginger juice yield were investigated.Futhermore,the process conditions of enzymatic hydrolysis were optimized by response surface methodology.The results showed that the optimized conditions were 7692 U/Kg of cellulase dosage,11893U/Kg of amylase dosage,enzymatic hydrolysis temperature 61?,and enzymatic hydrolysis time 1.5 h.Under these conditions,the juice yield was 74.65%and the soluble solids content was?18.43±0.84?°Brix.?2?In order to study the vacuum concentration process of ginger juice,the effects of vacuum,temperature and time on the concentration effect of ginger juice were investigated and the content of soluble solids was as the index.The vacuum concentration process conditions of ginger juice were optimized by orthogonal design.The results showed that the optimum conditions for vacuum concentration of ginger juice were vacuum 0.09 MPa,temperature 60?and time 60 min,rotation speed 100r/min.Under these conditions,the content of soluble solids in ginger concentrated juice reached 55°Brix,and reached the end point of concentration.?3?The effects of different concentration processes on the quality of ginger juice were studied.The volatile components of ginger juice before and after concentration were determined by GC-MS.Furthermore,the relationship between temperature and viscosity in the process of concentration of ginger vacuum concentrated juice was studied.The rheological properties of ginger vacuum concentrated juice were determined and the dynamic model of vacuum concentrated juice was established.The results showed that after vacuum concentration,the total sugar,total flavonoids and curcumin content of ginger juice were higher than that of concentrated ginger juice after normal pressure,while the browning degree was lower than that of concentrated ginger juice after atmospheric pressure.GC-MS analysis showed that the volatile components of ginger juice were mainly alcohols and alkenes,but after concentration there were only alkenes.The volatile components of vacuum concentrated ginger juice were more than those of atmospheric concentrated ginger juice.Moreover,the vacuum concentrated ginger juice was pseudoplastic non-Newtonian fluid.The viscosity of the ginger vacuum concentrate decreases with the increase of temperature accordingly.With the increase of shear rate,the viscosity of ginger vacuum concentrated juice decreased gradually,and it displayed a shear thinning phenomenon.The mathematical model reflecting the comprehensive effect of temperature and concentration on the viscosity of ginger concentrated juice was ??28?.21747?10^-5×EXP?_èRT^?36.8929-.05138×C?10?.00084×C²÷_?^?,R²=0.9784.The applicable ranges of the mathematical model were as follows:temperature 20?-60?,concentration 30-55°Brix.