Studies On Technology Of Hot-air Combined Microwave Vacuum Drying Of Carambola Fruit

Carambola?Averrhoa carambola Linn.?is a kind of Brand-name and quality fruit,produced in tropical and subtropical.The ripe fruit has rich nutrients with attractive golden color,which has healthy and pharmacological functions.According to the difference of the taste,carambola generally was divided into two categories,one is sweet,the other is sour.At present,the processing industry of carambola is at the stage of slow development in China,compared with the countries which have developed food industry,there is a big gap in the application of processing technology and the utilization degree of China's traditional carambola fruit processing industry.Therefore,adopting the advanced machining technology on researching the new type of carambola processed products have important significance to the development of China's processing industry and the utilization of carambola resources.In this study,the Red carambola was the experimental varieties,which were purchased in the fruit wholesale market of the sideline products logistics center in Fuzhou.Combined hot-air and microwave vacuum drying technology was used for the drying of carambola fruit slices.Protecting the carambola's color and shape without sulfur to determine the optimal process parameters before the drying process.On this basis,the hot-air drying characteristics and dynamic models of carambola fruit slices were studied as well as the microwave vacuum drying,At last,adopting the Response surface methodolog optimized the hot-air combined with microwave vacuum drying process,the optimal process parameters will guide the processing and production of carambola fruit slices in the future..In order to protect color and shape of the carambola fruit slices,this chapter selects of common browning inhibitors are NaCl,L-cysteine and calcium chloride?CaCl₂?,Reducing the problems of prone to brown and the shrinking deformation in the processing.According to the single factor experiments,researching the effect that soaking concentration,soaking time,soaking liquid ratio of browning inhibitors on the overall color and appearance of the dried fruit pieces.The study found that the smaller affect and the better processing immersion time is 30 min,and soaking liquid ratio is 1:3,the composite add reasonable use of color-protecting stabilizer can greatly improve the effects of color conformal,therefore,on the basis of single factor experiment,the three factors with four levels for L9?3⁴?orthogonal experiment were carried out to optimized the process,the optimal color-protecting condition is that,the concentration of NaCl is 0.45%,the concentration of L-cysteine is 0.10%and the concentration of CaC12 is 0.10%,,respectively.0.45%NaCl,0.10%L-cysteine,0.10%CaCl₂.The study adopts the traditional hot-air drying technology to research the hot-air drying characteristics and dynamic models of carambola fruit slices under different hot-air temperature,hot-air velocity,and loading capacity.It had decelerated drying period.The hot-air drying temperature had obvious effect on the rate of drying,the time of drying as well as the final quality of product in the whole process.In addition,in order to save the energy consumption in production applications,it suggests to control suitable range of material thickness.Moisture changing of carambola fruit slices in hot-air drying process could be described by Modified Henderson and Pabis equation.The results of the research on carambola's drying characteristics of microwave vacuum show that It had accelerated drying?constant drying and the decelerated drying period,the moisture of carambola mainly concentrated in constant drying stage with the swelling phenomenon.Microwave strength and loading capacity are two drying parameters that there are big effects on the time and rate of drying.It shows us that too strength of the microwave to burning materials and the Modified Henderson and Pabis model has the highest degree of fitting on the dataAt last,the study adopts the Response surface methodolog to optimized the hot-air combined with microwave vacuum drying process,the optimal process condition is:hot-air temperature was 69.95?,conversion moisture was 46.84%,microwave power was 4.94w/g,pressure was 75.01Kpa.the quality of drying carambola product is good under that conditions of process,it had complete pentagram and the attractive golden in color,the b*value of carambola fruit was 61.07,the energy consumption of joint drying was 3.23 kw/h,the sensory score of dried product was 92.83.According to the hazard analysis in processing process of carambola fruit,there are four key control points in the production of carambola fruit:the raw material acceptance;the Color conformal;Drying process;Storage conditions,On this basis,we had built the HACCP system which was used to the production of carambola fruit and it can improve the quality of the product.