Study On Processing Technology Of Compound Juice Of Pear And Wolfberry

Pear is one of the main fruits in China,and it has the effect of quenching thirst,moistening and clearing heat.However,pear has the characteristics of light aroma,insufficient flavor,poor color,and unsuitable storage.Therefore,the above characteristics are tested to select wolfberry juice with special aroma,bright color,high medicinal value and nutritional value,and complexed with pear juice.In terms of color,flavor and nutrition,we will learn from each other's strengths and improve the quality of juices.We will focus on the preparation process,blending scheme and stability of Fengshui pear wolfberry compound juice compound Juice.This paper from the following several aspects to conducts the research:1.Different varieties of pear juice characteristics of the analysis.The sensory evaluation and physicochemical index determination of fresh pressed pear juice of Yali,Snow Pear,Huangguan Pear,Xiangli,Nanguo Pear and Fengshui Pear were respectively measured.After synthesizing the physicochemical and sensory indexes of the juice,it can be seen that the juice yield,soluble solids and acidity of Nanguo pear were relatively high,and the fruit fragrance was strong.Yali pear and Xuehua pear have higher total acid content and higher food flavor,color,stability and quality.The juice yield and total sugar of Fengshui pear are higher,and its aroma was strong,but its total acid was lower and its flavor and color are slightly worse.The juice yield of fragrant pear and crown pear was relatively low,and their color was poor.2.The determination of color protection technology of Fengshui pear juice Different concentrations of sodium D-isoascorbate(0.1%,0.2%,0.3%,0.4%,0.5%),Vc(0.1%,0.2%,0.3%,0.4%,0.5%)and citric acid(0.2%)were used.0.3%,0.4%,0.5%,0.6%)as a color-protecting agent,the absorbance value A420 nm was measured and the browning inhibition rate was calculated,and the orthogonal test was performed according to the single factor result to determine the optimum colorant combination.The results showed that the three color-protecting agents were not ideal for the color protection of Fengshui pear.Theorthogonal test results showed that the addition of 0.4% vitamin C and 0.6% citric acid and0.5% D-isoascorbate had the most color protection effect.Well,the browning inhibition rate could reach 90.74%.3.The determination of the enzymatic hydrolysis process of Fengshui pear juice.Single factor and orthogonal experiments were performed with the amount of pectinase added,the temperature of enzymatic hydrolysis and the time of enzymatic hydrolysis.The experimental results showed that the optimum process parameters for enzymatic hydrolysis were pectinase addition 0.15%,enzymatic hydrolysis temperature 50 ?,and enzymatic hydrolysis time 2 h.Under this condition,the juice yield of Fengshui pear was 81.23%.4.The determination of the compounding scheme of Juice.Orthogonal test was designed by single factor design with pear juice addition,wolfberry juice addition,sucrose addition and citric acid addition.According to the flavor,color and aroma of the juice,the comprehensive score was made.Through experiments,the optimum formula parameters were25% of Fengshui pear juice,8% of wolfberry juice,2% of sucrose and 0.2% of citric acid.5.The determination of stabilizer for compound juice of of Fengshui Pear and wolfberry.With centrifugal precipitation rate as dependent variable,pectin,sodium alginate,carrageenan and CMC-Na were selected as experimental factors to conduct response test.The results showed that the optimum formulation of the composite stabilizer was 0.5% pectin,0.5% sodium alginate,0.5% carrageenan and 0.5% CMC-Na.Under this condition,the centrifugal precipitation rate of the composite juice was 0.89%.6.The determination of stabilizer for compound Juice of Fengshui pear and wolfberry.By evaluating the composite fruit juice beverage developed,the results of physical and chemical indicators were: soluble solid content was 10.68%,total sugar content was9.85mg/mL,light transmittance was 87.5%,pH was 4.15,total acidity was 0.146%,vitamin C content was 2.34mg/100 mL,total arsenic content was 0.052mg/L,lead content was 0.008g/L,copper content was 2.35 mg/L,zinc content was 1.45 mg/L,iron content was 5.57 mg/L,zinc,copper,iron total content was 9.37 mg / L;Escherichia coli,total number of colonies,pathogenic bacteria were in line with national standards.E.coli,the total number of colonies,and pathogenic bacteria are in line with national standards.The compound juice after sterilization and filling was stored in refrigerator and room temperature respectively.Thequality changes of the compound juice were observed regularly.The results showed that the compound juice was still light yellow,bright color,no precipitation and stratification,and the quality of the juice was better after 6 months at 4 ?.