| Nanguo pear pear is a kind of akiko pear in Rosaceae. It is easy to appear aging and corruption phenomenon under the condition of natural storage after 15 d, causing serious waste. To solve the problem of resources waste. ir not only can solve the save problem, but also can improve the value-added when Nanguo pear is processed into juice. Which is of great significance to promote Nanguo pear industry chain development. The processing technology, the product formula and stability of Nanguo pear were researched, providing certain reference for deep processing. the main research results are as follows:1. The color-preserving of different Color protection such as vitamin C, D-sodium isoascorbiate and citric acid and pectinase and cellulase on the pear juice juice yield were studied The results showed that the color-preserving was good with compound solution of 0.5% vitamin C, 0.4% D-sodium isoascorbiate and 0.2% citric acid, under that condition, the browning degree was as low as 0.102 and the colour was pale yellow;The juice rate is as high as 78.15%, the related physical and chemical index changed significantly(P < 0.05) when composite enzyme dosage, enzyme proportion, min enzymolysis time and enzymolysis temperature were 0.15%,3:1,119 min and 42 ℃,respectively.2. The impact of ultra high pressure(500 MPa, 10 min) and thermal treatment(95 ℃, 10 min) on the sterilization effect, nutritional quality, color and flavour of Nanguo pear juice were studied under the condition of stored at 4 ℃. Results showed that the sterilization effect was remarkable of UHP and thermal treatment, the total number of colonies and mold yeast in Nanguo pear juice achieved commercial sterilization during 35 d storage. Total phenol, total sugar and total content of Vc dropped, browning degree and the color difference increased as the extension of storage time, significantly Compared to the control group, change for each indicators was smaller with UHP treatment. Refers to the description that UHP can better maintain the nutrition of juice, fragrance and color.3. The chitosan clarification technology and beverage recipe of clarified fruit juice were studied. The results showed clarify effect is remarkable under the condition of0.722 g/L chitosan dosage, 45 ℃ flocculation temperature and 55 min flocculation time, the juice transmittance was 93.6%;The product had the optimal flavor with17.47% Nanguo pear juice, 8.15% sucrose, 0.02% citric acid and 0.08% malic acid. Atthis time, drink was yellow color, fruity, sweet and sour moderate, no obvious precipitation with 96.30 points sensory score.4. Nanguo pear juice beverage and its stability were studied. The results showed when the additive amount of 0.19%CMC, 0.20%carrageenan and 0.15%pectin, the beverage stability was optimal with minimum deposition rate 0.27%. while adding0.080% sucrose ester and monostearin(the proportion is 8:2), product had good suspension stability with 0.889 R value. Furthermore, it was confirmed that the Nanguo pear milk beverage stabilizing effect of compound stabilizer and emulsifying compound with 0.2~4 μm and 0.15~3.0 μm particle size distribution by path analysis; the best Nanguo pear milk beverage flavor was made up of 35% milk, 15% Nanguo pear juice,7% sugar and 0.30% citric acid, 0.064% sucrose ester, 0.016% monostearin, and42.08% drinking water with attractive uniform colour, sweet and delicious and delicate lubrication. |
