Research On High CO₂ Cooperative Ultrasonic And Decompression Processing Technology Of Pickled Watermelon Skin

Fruit and vegetable cull-fruit and processing by-products are industrial problems,their utilization rate and the added value is low.In the present study,we worked on watermelon skin-a representative by-product of fruit and vegetable,to develop pickled products.We mainly studied pretreatment parameters of raw materials,such as color protection,crispness and dehydration.We also researched flavoring formula and regularity of nutrition and quality change.Particularly,pickling process with high carbon dioxide combined with ultrasonic and decompression.We developed new products.As the main research and development content,through the appraise by experts of the Tianjin Municipal Science and Technology Commission on February 15,2017,and its level is advanced internationally.Track out a new way for efficient development of by-products of fruits and vegetables in China.1 Research on the raw materials pretreatment technology(1)Research on green-protecting processing of raw materials.Using single factor method to fix the initial alkali treatment conditions of watermelon skin.According to the orthogonal experiment range analysis,we determined the optimum process parameters of alkali treatment:alkali solution of 0.1%Na2CO3,the ratio of material to liquid at 1:11,soaking time of 40 min.To the best effect of preserving green,-a/b reached 0.35,40%higher than 0.25 in the control group.Then inactivating enzymes by hot blanching,the experiment showed that when the watermelon skin was blanched for 4 min under 95 ?,the peroxidase could be basically lost and the residual activity of POD was less than 5%,(2)Research on keeping brittleness processing of raw materials.Through the sensory evaluation method and single factor method and orthogonal experiment range analysis,determine the optimal parameters of keeping brittleness:solution of 0.15%CaC12,solid-liquid ratio 1:8,soaking time 20 min.To the best effect of keeping brittleness,the hardness reached 380 grams,increased by 23%compared with the control group 308 grams,ensure the crisp taste of dishes.(3)Research on dehydration processing of raw materials.The watermelon peel dehydration technology adopts the low temperature artificial hot air way,dehydration 50 ? for 5 h,can make the watermelon skin has good chewiness and the pickled vegetable unique hard and crisp taste,the sensory score is the highest,achieves 88.23,the dehydration rate is 25%-30%.2 Research on flavoring formulaThrough the experiment of single factor and response surface optimization,added flavor substances to increase the flavor and nutrition of the dishes.Basic formula is salt 4.5%-5%,pepper 34.1%,10.10%vinegar,onion ginger garlic 17.33%,sugar 4.74%,aginomoto 0.6%,thirteen sweet 0.9%,the sensory quality of products was 94.5,proper salt,full color and fragrance.3 Research on high CO2 cooperative ultrasonic and decompression technologyDetermine the optimal parameters of high CO2 cooperative ultrasonic decompression technology of pickled vegetables and fruits.That is,51.16%CO2(the remaining gas is N2),13.10 h is processed;the ultrasonic power is 51.48%,the ultrasonic time is 15.86 min/h,the 24 h is processed;the vacuum degree is-0.08 MPa,the 25.61 h is processed;and the curing efficiency is increased by 50%.The broken film of watermelon skin and the rapid permeation of seasoning liquid have been realized.