Study On Screening And Processing Technology Of Shelled Lotus Seed

Lotus seeds,an important special economic crop,which have been planted in 8 provinces including Fujian,Jiangxi,Hubei and Hunan province for a long history in China.Furthermore,the output of Lotus seeds in China accounts for more than 90%of the world's total.Due to the short shelf life and the starch staling as well as the browning during the storage of lotus seeds,the frozen fresh lotus seed and dried lotus seed are the main products on the market.In this research,Jianxuan No.17,Jianxuan No.35,Space lotus No.35 and Jingguang No.1 were selected as the main Fujian lotus seeds varieties to evaluate.Seeds of three different maturity were studied.Three different maturity levels of lotus seeds in each species including milk stage,dough stage and full ripe stage were used for the study.The nutritional quality and starch quality of fresh lotus seeds in different species at different maturation stages were analysis,then the suitable lotus seeds for processing were screened out and related processing characteristics were studied.The study provides a theoretical basis for optimizing the processing technology of shelled lotus seeds in conditioning foods.The mainly results are as follows:(1)Study the nutritional quality of shelled lotus seeds in different species at different maturation stagesIn order to screen the suitable shelled lotus seeds species for processing,the content of nutrients,mineral content,major non-metallic element content,amino acid content and sensory scores,etc.of four lotus varieties including Jianxuan No.17,Jianxuan No.35,Space lotus No.35 and Jingguang No.1 planted in Fujian as primary lotus seeds varieties were analyzed.According to the results,there was a significant difference in the major nutrients' content in fresh lotus seeds of the same species at different maturity stages.The maturity of fresh lotus was positively correlated with its nutrient content.Based on the above results,dough stage and full ripe stage of four varieties shelled lotus seeds was selected for further determination its quality characteristics of lotus starch.(2)Compare the quality characteristics of fresh lotus seeds starch in different species and different maturity stagesThe quality characteristics of lotus seed starch have great influence on the processing quality and edible quality of shelled lotus seeds.In this project,the characteristics of the starch in four lotus varieties were compared using scanning electron microscope(SEM),amylose automatic analyzer,X-ray diffractometer(XRD)and Malvern laser particle size analyzer.The quality characteristics of four variety lotus seeds' starch during the dough stage and full ripe stage were measured and analyzed.The amylose content,resistant starch content and particle size of lotus starch with different maturity of the same show a dependant with the maturity,while the crystallization of lotus starch with different maturity of the same variety decreased with the increase of the maturity of fresh lotus seeds(Except for Jingguang No.1).Among the four varieties,the starch content of Jianxuan No.17 and Jianxuan No.35 fresh lotus was higher in the dough stage and full ripe stage,while the content of amylose was much lower,which had a certain effect on inhibiting the starch retrogradation.Therefore,this study selected dough stage fresh lotus samples of Jianxuan No.17 and Jianxuan No.35 for further process optimization for lotus seeds with shell conditioning food.(3)Study the color protection process of shelled lotus seedsIn this project,based on single factor tests,a Box-Benhnken 3 factor 3 level response surface experiment was designed using Design Expert V8.0.6 data processing software,and the optimal parameters of the lotus color protection process for the Jianxuan No.17 dough stage were determined as follows:sodium carbonate soak handling time was 1 min,concentration of sodium carbonate was 0.42 mol/L,the blanching time was 5.15 min,the concentration of EDTA was 0.02 mol/L,the concentration of magnesium sulfate was 0.03 mol/L and the concentration of zinc chloride was 0.04 mol/L.The concentration of chlorophyll obtained from the validated experiment was similar to the predicted value,which shows that the reliability of the mathematical model established in this project is relatively high.At the same time,through the response surface design experiment,the optimal parameters for the color protection process of lotus seed during the dough stage of Jianxuan No.35 were determined as follows:the sodium carbonate soaking time was 1.5 min,the concentration of sodium carbonate was 0.3 mol/L,the blanching time was 4.75 min,the concentration of EDTA was 0.02 mol/L,the concentration of magnesium sulfate was 0.04 mol/L and the concentration of zinc chloride was 0.04 mol/L.The chlorophyll concentration obtained from the validated experiment is similar to the predicted value,which demonstrated that the reliability of the mathematical model established in this project is relatively high.(4)Study the ultrasonic impregnation process of shelled lotus seedsIn this project,based on single factor tests,a Box-Benhnken 3 factor 3 level response surface experiment was designed using Design Expert V8.0.6 data processing software,and the optimal parameters of the lotus color protection process for the Jianxuan No.17 dough stage were determined as follows:the ultrasonic power was 80%,the ultrasonic processing time was 20 min,the ultrasonic temperature was 40 ?.The chlorophyll concentration obtained from the validated experiment was similar to the predicted value,which shows that the reliability of the mathematical model established in this project is relatively high.The response surface design experiment showed the optimal parameters for the color protection process of lotus seed during the dough stage of Jianxuan No.35 were as follows:the ultrasonic power was 80%,the ultrasonic time was 20 min,the ultrasonic temperature was 40?.The chlorophyll concentration obtained from the validated experiment was similar to the predicted value,which shows that the reliability of the mathematical model established in this project is relatively high.