Membrane Separation Technology Treatment And Resource Utilization Of Bitter Almond Debittered Water

Peeling and debittering are deemed as two crucial steps in the industrial production and processing of apricot kernel.A lot of wastewater resources will be generated due to the process of peeling and debittering for the traditional apricot kernel processing industry.Meanwhile,a lot of nutrients contained in the wastewater will be discharged into the environment,resulting in serious pollution and resources waste.Therefore,the key technical problem of apricot kernle industrial treatment is how to use the green and efficient method to treat wastewater from peeling and debittering of apricot kernel.Based on the previous research in our laboratory,it is found that the method of saturated hot air is effectively applied in peeling the skin of apricot kernel,which greatly reduced the waste of water resources.In view of the treatment of apricot kernel debittering wastewater,the aim of this studies is that the change of nutrients and the improvement of water quality in the process of membrane filtration technology is analyzed,the wasterwater of recycling and utilization is carried out,and how to biodegrade the amygdalin in the debittering water of apricot kernel was discussed.The results showed that the membrane filtration technology can not only improve the concentration ratio of amygdalin,protein,polyphenol and other nutrients in the wastewater,but also significantly improve the water quality of the wastewater.The environmental monitoring indicators can meet the standards of drinking water.16s rDNA highthroughput sequencing analysis showed that a dominant fungus,irpex,was isolated,and had a degradation effect on amygdalin to some extent.That is to say,the membrane filtration method could be applied to the treatment of apricot kernel debittering wastewater,and the ultrafiltration water could be applied to the development of beverage because of a certain amount of effective substances such as amygdalin and benzaldehyde.That not only conformed to the concept of green environmental protection,but also promoted the development of apricot kernel processing industry,improves the added value of industry and increases economic benefits.The specific research contents and results are as follows:1.The secondary membrane filtration technology with different pore size and pressure of ceramic membrane was used in the treatment of apricot kernel debittering wastewater,and the change of nutritional components in the process was studied.The results showed that the energy consumption and the pollution of ceramic membrane and organic membrane was small when the pore diameter of ceramic membrane was 8 nm and the pressure of ceramic membrane was 0.5 MPa.The concentration of amygdalin in the organic membrane concentrate can reach 2.7,which was beneficial to recovery of amygdalin when the molecular weight of organic membrane filtration liquid was 150-300 Da and the pressure of membrane was 2 MPa.A large number of ultrafiltration water can be collected in the process of membrane filtration.It can be seen form the color difference and the change of various material components that the ultrafiltration water had hardly effective substance such as amygdalin,protein,polyphenol,flavone,etc.Meantime,the L*is large,which indicated that the ultrafiltration water is clear and bright.The ultrafiltration water can be used as raw materials for the follow-up development of apricot kernel beverage and improve the added value of apricot kernel processing industry.2.The water quality of ultrafiltration water was analyzed.Response surface,electronic nose and electronic tongue are used to study and verify the formula of apricot kernel beverage.The volatile components in the beverage were analyzed by GC-MS.The determined results of the hygienic parameters suggest that ultrafiltration water meets the environment standards of the drinking.Taking the ultrafiltration water as the raw material,the formula of the apricot kernel beverage was optimized by response surface methodology which showed the optimum formula of the product were:the ratio of material to liquid 3:1,sugar 6%and citric acid 0.06%.The apricot kernel beverage with this ratio had better taste and color.Under the condition of electronic nose,electronic tongue and GC-MS test,it was confirmed that the optimal formula conforms to the theoretical value.The results of GC-MS indicated that the relative content of benzaldehyde,a natural aroma substance,was present in beverages.3.Microscopic observation and biological analysis of the unknown bacterium in the debitterring water of apricot kernel was observed,and the degradation of amygdalin and its mechanism were studied.16s rDNA high-throughput sequencing analysis showed that 98%of the dominant bacteria were Irpex,99%of the dominant bacteria were Trichoderma.According to the references,white rot fungus also has the corresponding degradation effect and the morphology and microstructure were similar.Therefore,the degradation of amygdalin by Irpex,Trichoderma and white rot fungus was studied.The results showed that Trichoderma and white rot fungus had no effect on the degradation of amygdalin.However,the optimal culture method of Irpex had better degradation effect on amygdalin in the concentration of 6.4×106 CFU/mL6.4×107 CFU/mL.As the same time,it was verified that the degradation of amygdalin by Irpex was not produced by β-glucosidase.This study can provide a data and theoretical basis for the wastewater treatment of apricot kernel processing enterprises,and provide the optimal formula for apricot kernel beverage production.The industrial added-vaule of apricot kernel and economic benefits are increased by this studies.