| Nanfeng mandarin is a unique citrus variety in Nanfeng County,Jiangxi Province,with a history of thousands of years of cultivation.So far,the development of Nanfeng's orange processing industry has been lagging behind,which has severely restricted the development of this industry and the increase of farmers' incomes,which has caused waste of orange resources and environmental pollution.As a result,our research team has carried out the research and development of Nanfeng mandarin fruit vinegar and has successfully industrialized it.In order to make full use of Nanfeng mandarin resources,this study took fresh Nanfeng mandarin orange peels as the object,carried out the research on the extraction of essential oil and pectin,and on the simultaneous extraction process of the essential oil and pectin of Nanfeng mandarin orange peel,which lay a theoretical and experimental basis for the full utilization of Nanfeng mandarin resources.(1)The research on the extraction process of the essential oil of fresh Nanfeng mandarin orange peel was carried out.Through single factor and response surface optimization,the best process to obtain continuous solvent-free microwave extraction is: microwave power is 660 W,microwave reaction time is 20 min,water content is 60%,and the essential oil yield is 3.47% under these conditions.The intermittent solventfree microwave extraction method is proposed and the process is optimized.The optimal process parameters are: microwave power of 380 W,water content of 50%,microwave single reaction time of 6min,microwave single interval time of 15 min,microwave reaction times for 4 times,the yield of essential oil under these conditions is 3.51%.Compared with extraction methods such as steam distillation,Na Cl salting out and continuous solvent-free microwave extraction,the essential oil obtained by batch-type solvent-free microwave extraction has high yield,good quality,and low CO2 emission and low energy consumption.The four extraction methods are similar in composition of essential oils,and all of them are mainly D-limonene.(2)Research on the extraction technology of fresh Nanfeng mandarin orange peel pectin.The extraction rate of pectin optimized by the microwave-assisted acid extraction method is about 10.41%,which is higher than that of the traditional acid extraction and alcohol precipitation method(8.16%).The galacturonic acid content of the pectin extracted by the microwave-assisted acid extraction method is 76.02%,the degree of esterification is 72.08%,the equivalent is 1910.1,and the methoxy content is8.74%,showing good performance.(3)The feasibility of simultaneous extraction of Nanfeng mandarin orange peel essential oil and pectin was discussed.First,the optimization of the simultaneous extraction of essential oil and pectin with continuous microwave-assisted acid was carried out: when nitric acid was used as the acidifier,the microwave power was 660 W,p H3.5,and reaction time 10 min,and the yields of essential oil and pectin were 3.71%and 3.51%,respectively;When citric acid is used as an acidifier,the microwave power is 660 W,p H3.0,and the reaction time is 10 min.The yields of essential oil and pectin are 3.60% and 5.54%,respectively.Second,the optimization of the simultaneous extraction of essential oil and pectin with intermittent microwave-assisted acid was carried out: when nitric acid was used as the acidifier,the microwave power was380 KW,p H3.0,and the reaction time was 12 min.The yields of essential oil and pectin were 3.20% and 5.34%,respectively;When citric acid is used as the acidifier,the microwave power is 380 KW,p H 2.5,reaction time 12 min,and the yields of essential oil and pectin are 3.60% and 3.67%,respectively.This shows that in the microwave synchronous extraction process,the addition of acid is beneficial to accelerate the precipitation of essential oils,but is not conducive to the extraction of pectin. |
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