Study On Processing Technology Of Vacuum Fried Crispy Peas Using Dried Pisum Sativum Linn As Raw Material

Demands of fresh peas always exceed supply due to obvious seasonality and poorstorage property. On the contrary, dried peas as processing raw material are easily transportedand don’t require specialized storage, which allows them to be processed in the off-seasonwhen demand is high. What’s more, the capital investment of freezing storage in factories canbe reduced by using dried peas. At present, pea products as snack food in market have somedrawbacks, such as the over high content of added pigment, short shelf-life and high oilcontent. Compared with atmosphere frying, vacuum frying can keep color, nutrition andflavor of products, which have lower oil content. In this paper, by using low cost dried peas asraw material, the effects of pretreatments and vacuum frying conditions on the quality ofcrispy peas were studied, which provided some basic theories on processing low cost and highquality leisure food.In order to ensure the crispness and color stability of vacuum fried peas, the rehydrationproperty of dried peas and the effect of moisture content of rehydrate peas on crispness ofproducts were researched first. The results showed that the soaking conditions were soaking at5°C for14h,25°C for8h and35°C for4h approximately and the moisture content ofrehydrate peas more than50%could ensure the crispness of products. Four blanchingconditions were determined by POD enzyme’s inactivation, and then the effect of fourconditions on the quality （color, texture and chlorophyll content and so on） of vacuum friedpeas was comparaed. The results showed that the optimum condition was blanching peas at100°C for1min. The effect of different color fixatives on the color of crispy peas wascompared, and peas with2%（W/V） NaHCO3color-protecting showed the best result.In order to reduce the oil content of crispy peas, the effect of the three pre-treatments（carboxymethylcellulose coating, hot-air pre-drying and vacuum microwave pre-drying） onthe oil content and other qualities were studied. The results showed that pre-drying andcoating could reduce the oil content of products significantly. Vacuum fried peas pre-treatedwith vacuum microwave pre-drying （power343±2.2W, vacuum degree0.060MPa,pre-drying time8min） were tasted crispy and had good color and highest overall quality.The quality of vacuum fried peas was compared by using fresh peas and rehydrate peasas raw material. The sensory evaluation showed that there was no significant difference on theoverall quality. Therefore, fresh peas could be replaced by dried ones to produce snack infactories.The effect of material oil ratio on the moisture and oil content of vacuum fried peas wereresearched, and30g/L was confirmed as the optimum condition. Then the Response SurfaceMethodology based on the single-factor test was chosen to evaluate the oil content andbreaking force of crispy peas. The results showed that the optimum frying conditions were:vacuum frying temperature of100¹05°C, frying time of18min and the vacuum degree of0.090⁰.095MPa. The effect of de-oiling conditions on the oil content of vacuum fried peaswas then studied, and rotation speed of350r/min and de-oiling time of8min were confirmed.According to the result of the single-factor and orthogonal experiment, basing on the weight of vacuum fried peas, the optimum formula was achieved on according to sensory score:mustard powder2.0g/100g, salt1.5g/100g, I+G0.04g/100g and white granulated sugar0.5g/100g.In order to research the storage stability of crispy peas at room temperature, the qualitychanges of the products were tested at room temperature. The results showed that somephysicochemical properties of crispy peas had changed a little in six months, but the qualitycould be accepted. To predict the shelf life of products at room temperature, vacuum friedpeas were stored at higher temperature. The kinetics model of acid value was B=0.12e0.0125t,and the prediction of the shelf life were257days. Peroxide value dynamic model of productswas B=0.78e^0.0138t, and the prediction of the shelf life were234days.