| Granny Smith is one of the green apple varieties with world-renowned reputation, and original product in Australia. It was introduced and cultivated to China with large area, and was proved that it adapt to the climate and soil condition of northern China. Granny Smith has smooth, emerald green outer skin, and green and white fruit pulp. It also has the quality of brittle, high acidity and very resistant to storage. It is the ideal and dual-purpose varieties of apple for processing and eat. Granny Smith is the best choice and good variety for apple processing as a typical representative of the high acidity of apple. Not only it can be processed into juice concentrate, but also can be processed into sauce, beverage and other frozen products.Cold crushing method is an advanced technology that apple peel, fruit seeds and stalk were separated previously from apple pulp to manufacture high-quality products before apple squeezed. Granny Smith pulp of which produced with cold-crushing separation technology has higher quality than its of the traditional process, and it retaining better nutrition. Currently, the utilization and the research of Granny Smith pulp from cold crushing method are rare among domestic and foreign researchers. Therefore, it is necessary to discuss the material properties of Granny Smith pulp with cold crushing method, and develop the relative products.In this experiment, the material properties including its nutritional properties, freezing point characteristics and rheological behavior were exploited to provide a theoretical basis for the deepth improvement using the cold crushing Granny Smith pulp as raw materials. At the same time, the pulp beverage and its formula of Granny Smith was developed with healthy nutrition, low heat and delicious taste. The smoothie products and its recipe also produced with rich dietary fiber content on the basis of above test results. All of products above will enrich the product range of Granny Smith. The main results were as follows:1. Using the patented cold crushing equipment to prepared the Granny Smith fruit pulp, and study its nutritional characteristics and index through method of chemical analysis. The results showed that the moisture content of Granny Smith pulp was 84.63% and total solids content of 13.1°Brix, acidity of 0.78%. total sugar content of 13.69%, total phenol content of 33.65 mg/L, as pectin, dietary fiber and Vc content was 0.34%,1.31% and 80.67mg/kg respectively. The measurement result of pulp color display that its brightness of L value, a value and b value was 41.19,8.41 and 0.85 respectively. All of above data show that Granny Smith fruit pulp contains rich nutrient, possess high acidity and pale green color. It is the most suitable variety for apple processing now.2. Using the equipment of low temperature and thermostatic control temperature bath to study the freezing point characteristics of cold crushing fruit pulp of Granny Smith. The experiment confirmed that the freezing point of Granny Smith fruit pulp was-2.5 C. This result will provide a reference to choice an optimal temperature for further cooling product of pulp or freezing storage of raw materials. The research result showed that the freezing temperature of fruit pulp has very significant negative correlation with total soluble solid content, and the higher of TSC, the lower of the freezing point. It was benefited to the storage of fruit pulp in low temperature. The result also showed that the freezing temperature of fruit pulp has significant negative correlation with pH, and the higher of pH, the lower of the freezing point. But there has significant positive correlation between TSC and pH. The changes of refrigerant temperature did not lead to change of freezing points during the test period, but the lower of the refrigerant temperature, the sooner of the freezing point of fruit pulp would be tested out in experiment.3. The rheological properties of cold crushing fruit pulp of Granny Smith was studied using the digital rotary viscosity instrument. This fruit pulp was a type of pseudo-plastic, non-Newtonian fluid with the flow behavior index of 0.37. But in the dilution process of Granny Smith fruit pulp, the fluid type of fruit pulp turned into Newtonian fluid according the mass fraction decrease of fruit pulp. When the content of fruit pulp reduce to 10%, the fluid of fruit pulp has showed the characteristics of Newtonian fluid.4. The product formulation of pulp beverage was determined using single factor experiment. This experiment was conducted from six aspects of the pulp content, the ratio of sugar to acid determination, sweetener, stabilizer and natural essence selection, sensory evaluation. The pulp beverage recipe ultimately was determined, and they were as follows:the dosage of fruit pulp of Granny Smith was 50%(TSC is13.1°Brix with acidity of 0.78%), ratio of sugar to acid was 22:1, the dosage of sweetener (ratio of stevioside and erythritol was 1:8) was 1.67‰, the stabilizer of flax-seed gum was 0.15%, as the content of natural essence(IFF SC526009:FENHAO essence of 1:1) was 0.04%. The product of pulp beverage from Granny Smith was produced in this experiment, it has light yellow color, sweet and delicious taste, and rich flavor of green apple. The product also was one kind of healthy nutrition beverage with rich dietary fiber, and lower heat and sugar.The smoothies product of Granny Smith pulp was prepared through smoothies machine, and the formulation of smoothies was determined by the sensory evaluation and assessment method. The recipe of smoothies were as follows:the ratio of fruit pulp(TSC of 13.1°Brix with acidity of 0.78%) and water was 1:1 (kg/kg), then add sucrose of 15%, citric acid 0.3% and natural apple essence(IFF SC526009) 0.04% into diluted pulp to mixed totally. After homogenization and sterilization, the raw materials was pour into the sorbet machine and string of 60 minutes to produce smoothies product. This kind of smoothies has appropriate sweet and sour taste, cool and refreshing flavor with rich dietary fiber. |
PDF Full Text Request