| Pumpkin nutrition is rich, its resource is very wide, and has a long storage period, is easy to transport, is advantageous to process. As a result of the pumpkin nutrition value has not been widely recognized, they always regard it as an inferior vegetable, most as feed processing. In recent years, the study found that pumpkin is not only nutritious, but also has care function and medicinal value. Therefore, People are keen to develop pumpkin series products. Pumpkin powder is the most main products of pumpkin series products, its demand continuously in the market. This topic make fresh pumpkin as the raw material, by optimizing the inhibiting Browning process conditions, multiple enzyme combined with microwave process conditions, and the drying process conditions in the process of Pumpkin powder production, in order to solve the deeper colour and lustre, serious nutrient substance loss, poor water-soluble, taste rough problems in the traditional craft.Firstly, with PPO relative activity and color difference as evaluation indexes, this Paper selects the best treatment method, established the microwave processing method and optimized experiment, identified with optimum process conditions of inhibiting Browning of the microwave power, microwave time, slice thickness. It is as follows:microwave power for 385w, microwave time for 3min, slice thickness of 6 mm, the relative activity of PPO was 22.88%, the color difference was 3.77.Secondly, in order to improve its soluble sugar content and improve the efficiency of the enzyme solution, selecting multiple enzyme combined with microwave process methods and optimize the experiment, with soluble sugar content in pumpkin pulp as evaluation indexes, the paper uses the response surface method to study the mixing enzyme ratio of pumpkin pulp, identified by pectinase, alpha amylase, saccharifying enzyme for the best proportion is:the dosage of pectinase was 0.03%, the dosage of alpha amylase 0.60%, the dosage of saccharifying enzyme was 1.14%, soluble sugar content is 5.32%. On the basis of the optimal mixture enzyme ratio, using the uniform design method to study the enzymolysis process conditions, identified with enzyme solution temperature, enzymolysis time, shaking speed for optimum process conditions is:enzyme solution temperature was 60℃, enzymolysis time was 2.5 h, shake speed was 120 r/min, the soluble sugar content in pumpkin pulp is 5.43%. Finall, the mixing enzyme combined with microwave process conditions were studied, results show that after enzymolysis 1h, selecting microwave power for 231 w, after microwave 3min, soluble sugar content as high as 5.84%.Paper further comparativly studied microwave drying, vacuum drying, vacuum freeze drying in three different drying methods on the quality effect of pumpkin powder, finally got under the condition of vacuum freeze-drying, the pumpkin powder quality is best, the Vc content was 115.50mg/100g, beta carotene content was 33.15mg/100g, sensory score was 86 points, total phenol content was 3.84 mg/g, soluble sugar content was 6.35%, repose Angle was 38.7°, the density was 0.7087g/mL, solubility was 0.283%, water-holding power was 5.64g/g, oil-holding power was 4.76g/g, the maximum of DPPH-clearance rate was 89.77%.At last, the physicochemical characteristics and antioxidant properties of two kinds of pumpkin powders for A and B were analyzed. Compared with A pumpkin powder, in the nutritional ingredients of B pumpkin powder, moisture, ash, protein, dietary fiber, soluble sugar, total phenol content were increased; Fat, carbohydrates, Vc, beta carotene content were decreased; In the physical properties, Angle of repose was reduced, bulk density, solubility, water-holding power, oil-holding power were increased; In the antioxidant activity, the maximum of DPPH·clearance rate fell slightly. |
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