Research And Product Development Of Kiwi Fruit Pulp Processing Technology Based On Cold Crushing Technology

Kiwi fruit is a kind of nutritious and delicious fruit.It not only has the functions of preventing cancer,anti-oxidation,anti-aging,but also can improve immunity and regulate adipocyte differentiation.Therefore,its research and development will bring broad prospects.Kiwi fruit is abundant in China,but the deep processing and comprehensive utilization of kiwi fruit are still in the early stage.In the processing of kiwi fruit,there exist many problems,such as limited product,relatively backward technology,large waste of by-products,high production cost which hinder the further development of the industry.It is necessary to explore the whole fruit utilization of kiwi fruit,optimize the processing technology,reduce the quality changes in the processing and develop the kiwi fruit products which are rich in nutrients.Based on kiwi fruit as raw material.First the effect of traditional crushing process and cold crushing process on the quality of three kinds of kiwi fruit was compared.And then response surface methodology(RSM)was used to optimize the sterilization conditions of ultra-high pressure on Hayward pulp,and the quality changes of the sterilized kiwi fruit pulp during storage were studied.At last,Hayward powder which was low in calorie was developed,and the influence of different drying methods on the quality of fruit powder was explored.The main conclusions are as follows:1.Compared with the traditional crushing process,cold crushing technology improved the contents of total acid,Vc and the percentage of pectinase.Meanwhile,the contents of polyphenols,pectin,protein and the activities of polyphenol oxidase and peroxidase were significantly decreased.However,there was a little effect on the total sugar and reducing sugar.2.The sterilization conditions of ultra-high pressure on Hayward pulp were optimized.The results showed that optimal conditions were pressure of 497 Mpa,temperature of 27℃,holding time of 24 min.3.As a new type of non-thermal sterilization,ultra-high pressure had good bactericidal and enzymatic effects on kiwi fruit pulp,and the physicochemical properties,nutrient attributes of sterilized kiwi fruit pulp were almost retained.With the extension of storage,the pH value,the contents of Vc,polyphenols and pectin were all decreased significantly.Browning degree,total color deviation and total acid were increased.It’s benifical for further process of kiwi fruit pulp.The contents of souble solids and total sugar were basically unchanged.4.By using sterilized Hayward kiwi fruit pulp,the powder formula was obtained.The optimal formula was pulp concentration 80%,stevioside 0.02%,erythritol 2.88%,maltodextrin 30%,soluble starch 10%,β-cyclodextrin 10%.5.The quality indicators of kiwi fruit fruit powder which obtained by vacuum freeze drying and spray drying were compared.Freeze drying powder had the large gap,loose tissue and less cohesive force.Its agglomeration degree,bulk density,repose angle and dissolution time were significantly lower than those of spray drying powder.Because the freeze drying temperature was low,the nutrient was more closed to the original kiwi fruit fruit.