| Citrus is the world’s first large fruit, more than one hundred million tons of the global output as early as 2005, in the production processing of orange will produce a lot of pericarp, representing approximately 40%-50% of the fresh weight. Pericarp directly buried or processed into animal feed in traditional processing industry. The pericarp can easily mildew smell and cause the environmental pollution. If processed into animal feed, additional value is limited and need to consume a lot of energy, the economic and social value is not enough. Therefore, it is necessary to comprehensive utilization of citrus peel, not only can improve the economic efficiency of citrus processing industry, also is an important environmental initiatives.The paper mainly from the perspective of powder preparation, obtained superfine powder by the preparation process of exploration and optimization, and study on the properties of the superfine powder,focus on the difference of the properties and overall smell changes of the superfine powder in different sizes. The discussion and the research has some theoretical significance and application value of food, medicine processing and other fields for citrus peel. The content and results of the study are as follows:1. Study on effect of drying methods on the peel powder preparationSelection of Mandarin orange peel, lemon peel and Jincheng orange peel as raw material, drying the orange peel by use of ambient pressure drying, vacuum drying, vacuum freeze drying, then make preparation of powder by ultrafine grinding. Determination of particle size distribution of the powder by using laser particle size analyzer, determination of water-holding capacity, oil-holding capacity, chroma value and other indicators by using of physical and chemical methods, determination of the content of bitter substances in powder by different drying methods treatment by using high performance liquid chromatography and the energy consumption by using different drying methods. The results are powder particle size distribution is better, physical-chemical indicators are better, the content of bitter substances are least and energy consumption is the lowest by using ambient pressure drying, the drying method is suitable for application of industrial production.2. Study on effect of crushing methods on the peel powder preparationAt ambient pressure in drying condition, select universal grinder, ball mill, ultra centrifugal grinding apparatus to crush orange peel respectively, Determination of particle size distribution of the powder by using laser particle size analyzer, we found that the particle size distribution is better and powder particle size is smaller by using ball mill. However, the milling process is longer, the energy consumption is huge, and will make a tremendous noise pollution. Therefore, consider of the actual application, we attempt to explore the centrifugal grinding process, to get the best crushing process, finally to achieve the best crushing effect.On the basis of single factor experiment, the ultra centrifugation grinding process optimized by Box-Behnken experiment design and response surface methodology analysis applying Minitab 15 statistical software, the models based on quadratic polynomial regression equations of Specific surface area that affected by coarse powder particle size, rotate speed, grinding times were carried out:Y=0.215727-0.012X1+0.0054X2-0.0006X3-0.010818X12-0.007818X22-0.015818X 32-0.003750XiX2-0.01875XiX3+0.00725X2X3.The optimum processing parameters was:coarse powder particle size 60-80 mesh, rotated speed 16000 r/min, grinding 3 times.Analyze the powder obtained by optimized ultra centrifugal grinding and ball milling by laser particle size analyzer, compare and determination the water-holding capacity, oil-holding capacity, the chroma value, solubility, swelling, foaming, foam stability of the powder by physical-chemical methods, we found that the properties of two kinds of powders are closely, the optimization achieve the desired effect.3. Study on powder properties with different particle sizePreparation of powders based on the process of chapter 2 and 3, divided the powders into 250 mesh,200mesh,140mesh by using grading sieve. Using physicochemical method for the determination of the angle of reponse, bulk density, tap density to reflect the liquidity and filling of the powders. We found that the fluidity and filling of the superfine powder is better than that of ordinary powder.Determination of moisture absorption properties of powders with different particle size by physicochemical method, we got the conclusion that the moisture absorption time is longer than ordinary powder and the processing procedure of superfine powder should be carried out with strictly dry condition.Based on the analysis on active ingredient-total flavonoids of powders with different particle size, we found that micronized to certain extent contribute to the dissolution of the active ingredient, however, if micronized too fine, it will impede the dissolution of the active ingredient, the content decreased.4. The effect of particle size on powder flavor changesMake comparison and recognition of the aroma from mandarin orange peel powder and lemon peel powder with different particle size by using electronic nose, explore the sensitivity of the electronic nose to distinguish the aroma from powder with different particle size. The results show that the odor fingerprint analyzer can accurately distinguish the smell of peel powder with different particle size, and it can reflect the three-dimensional space clustering distribution of powder with different particle size by 3D stereo. |
