| Rosa roxbunghii, possessing health and pharmacological function, is a valuable characteristic resource in Guizhou province and has been applied widely in the field of food, medicine and health functional food. Rosa roxbunghii pomace, occupying 50%of fresh fruit, is nutrient-rich. However, it is still an unsolved problem due to the lack of related technology research. Therefore, research of high value utilization technology can fully play the resource advantage, reduce waste emissions and product high added value production, which will be of great importance in promoting Rosa roxbunghii industry and local economic development.In order to promote Rosa roxbunghii industry development, taking Rosa roxbunghii pomace as research objects, the paper investigated pomace dried preservation processing, optimization of extrusion modification condition, superfine grinding by dry processing and quality of different pomace fiber products. The main research contents and results were as follows:1. Rosa roxbunghii pomace was treated by heated-air drying, far infrared drying and vacuum drying. The result showed that, the best temperatures for heated-air drying far infrared drying and vacuum drying were 50℃, 50℃ and 70℃, respectively.According to pomace quality and Topsis analysis, the drying effect was as follow: far infrared drying >vacuum drying >heated-air drying. The best drying method was far infrared drying at 50℃, according to the ideal color and nutritional ingredient.Seven drying models were matched in non-linearity on the basis of moisture variation during drying. The drying model of all the three drying method was Midilli and Kucuk model. Proved by proven test, Midilli and Kucuk model was suitable for Rosa roxbunghii pomace drying.2. Twin-screw extrusion technology was used for Rosa roxbunghii pomace modification treatment. The moisture content of materials, extrusion temperature,screw speed and feed rate were selected as single factors for orthogonal test.The optimum extrusion conditions were as follows: moisture content 33%, temperature150 ℃, screw speed 144 r / min and feed rate 79.2r / min. The moisture content,extrusion temperature, screw speed and feed rate had extremely significant(P< 0.01)influence on SDF of Rosa roxbunghii pomace. The verification test showed that, SDF content was19.87%, which was 3.08 times of the original content.3. Twin-screw extrusion, superfine grinding and superfine grinding extrusion were used to modify Rosa roxbunghii pomace. Through the comparison of the basic components of the sample, morphology structure and physicochemical property, the result showed:(1) SDF content after modification was extremely significant different compared with control group(P <0.01). The SDF content of extrusion group was3.11 times, and extrusion superfine grinding group was 2.68 times as much as the control group. With the decreasing of particle size, the protein and SDF content increased. When the particle size ≤48μm,the SDF content increased 113.13%compared with the control group.(2) Through electron microscope scanning, the result showed that, compared with the control group, the fiber structure was destroyed and the particle was smaller after modification. The extrusion group was porous block. The structure of superfine grinding and extrusion superfine grinding showed multilayer irregular sheet.(3) After modification, physical and chemical properties changed significantly. With the decreasing of particle size, expansive force and water-holding power decreased after superfine grinding. The superfine grinding extrusion group was significant different compared with control group and extrusion group(P <0.05). The expansive force, water-holding power and water solubility of superfine grinding extrusion were decreased compared with twin-screw extrusion. Compared with control group, the expansive force and water solubility of extrusion group increased 1.16 times and 2.62 times, respectively(P<0.01).(4) The cation exchange capacity of pomace treated by different modification method was higher than control group(P <0.05) and superfine grinding extrusion group was significant improved. The glucose adsorption capacity increased significantly compared with control group(P <0.05). With the increasing of the concentration of glucose in the solution, it was increased.4. Tests on blood sugar and blood lipid regulation of alloxan-induced hyperglycemia and high blood fats mice, and antioxidant ability including heart, liverand kidney of cardiac D- galactose-induced aging mice were conducted. Results showed that, compared with control group,the blood sugar content of superfine grinding and superfine grinding extrusion decreased by 20.71% and 18.51%(P < 0.01),respectively. In the high lipid mice test, the TC and TG content of superfine grinding and superfine grinding extrusion decreased by 49.22%, 50.50% and 37.81%, 40.33%(P <0.01), respectively; compared with control group, HLD-C content of the high-dose and middle-dose group increased 148.94%, 132.98% and 128.72%(P <0.01),respectively. In the antioxidant test, both of high-dose and middle-dose group from raw pomace and pomace treated by superfine grinding had significant anti-oxidation and anti-aging effects. The middle-dose and low-dose group of fermentation group possessed poor anti-oxidation and anti-aging effects.The physicochemical properties and physiological function of Rosa roxbunghii pomace were improved by modification. After modification, the pomace can be used as base for functional food, which will provide theoretical and technical support for high-fiber products development. |
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