| Hazelnut protein is a high-quality plant protein with good edible and medicinal value.The green,efficient and pollution-free extraction of hazelnut protein has become a research central issue in the field of food processing.The current conventional methods of plant protein extraction mainly include alkaline solution,water solution,and water enzymatic method.However,these methods have a series of shortcomings such as low extraction efficiency,long time consuming,and serious environmental pollution.Therefore,the industry urgently needs an efficient,fast,low cost,and low pollution method for extracting hazelnut protein.In response to the above problems,this subject proposes a method for extracting hazelnut protein based on ultrasonic and mechanical cell wall breaking technology.First,the mechanism of ultrasonic and mechanical cell wall breaking to extract hazelnut protein was studied.Secondly,the influence of operation parameters and structure parameters on the sound field distribution in the ultrasonic extraction process was analyzed by simulation.Finally,the effect of different process parameters on the extraction rate of hazelnut protein under the action of ultrasonic combined ball milling and ultrasonic combined shearing was studied and analyzed through experiments.The main research content and results of the thesis are as follows:(1)The extraction mechanism of ultrasonic and mechanical crushing was deeply analyzed.First of all,the composition and function of the key ultrasonic device,as well as the generation and action process of ultrasonic were described.The cavitation effect,mechanical effect,thermal effect and chemical effect of ultrasonic wave analyzed.At the same time,based on Fick's law,a dynamic model of ultrasonic extraction was established to provide a theoretical basis for subsequent experiments.Secondly,analyze the motion mechanism and wall breaking mechanism of the planetary ball mill,the motion state and force of grinding tank,grinding medium and material are analyzed respectively,and the velocity equation and force equation are derived.Finally,the extraction mechanism of cell wall breaking by shearing was analyzed,and the extraction mechanism of cell wall breaking by shearing based on turbulence and laminar flow,cavitation and mechanical action was discussed.(2)The distribution of sound field in the process of ultrasonic extraction was simulated and analyzed by COMSOL software.First,the ultrasonic extraction model was constructed,the acoustic wave equation was solved,and the mesh was divided.Secondly,the impedance,sound pressure and attenuation coefficient were analyzed and solved,and the boundary conditions in the simulation process were set.Finally,the effects of different ultrasonic power,ultrasonic frequency,ultrasonic probe diameter,ultrasonic action depth,ultrasonic extraction container shape and material on the sound field distribution in the ultrasonic extraction process were studied respectively.The simulation results show that the sound pressure generated by the ultrasonic extraction of hazelnut protein in this experiment can exceed the cavitation threshold,which can effectively break the wall of hazelnut protein cells.The optimum conditions for extracting hazelnut protein were as follows: the ultrasonic frequency was 20 k Hz,the diameter of ultrasonic probe was 25 mm,and the depth of ultrasonic probe was 3.5 cm.(3)The method of ultrasonic combined with planetary ball mill to break cell wall was used.The effects of different extraction conditions on the extraction rate of hazelnut protein were studied.The effects of different ultrasonic time,ultrasonic power,liquid-to-material ratio,particle size of hazelnut powder,water bath temperature and extraction p H on the extraction rate of hazelnut protein were studied respectively.The results showed that the extraction rate of hazelnut protein could reach 87.83% with ultrasonic time at 8 min,p H value at 9,ultrasonic power at 180 W,liquid-solid ratio at 25 m L/g and hazelnut powder particle size at 5.98 ?m.At the same time,Ultrasonic time(ln t),ultrasonic power(ln P)and hazelnut protein extract concentration(ln C)showed a linear relationship,and the ultrasonic extraction kinetic model was verified.(4)The method of ultrasonic combined shearing and crushing was used to study.The effects of different extraction conditions on the extraction rate of hazelnut protein were studied.The effects of different ultrasonic time,ultrasonic power,shear time,liquid-to-material ratio,water bath temperature,extraction method and salt solution concentration on the extraction rate of hazelnut protein were studied respectively.The research results show that the extraction rate of hazelnut protein can reach 86.3% with ultrasonic time at 8 min,ultrasonic power at 450 W,liquid-to-material ratio at 25 m L/g,and salt solution solubility at 1 mol/L.At the same time,Ultrasonic time(ln t),ultrasonic power(ln P)and hazelnut protein extract concentration(ln C)showed a linear relationship,and the ultrasonic extraction kinetic model was verified.The technology of ultrasonic and mechanical cell wall breaking technology was used to extract hazelnut protein.The effects of key technological parameters on the extraction rate of hazelnut protein were analyzed.The cell wall breaking extraction mechanism of ultrasonic,planetary ball milling and shearing technology was analyzed.The influence of different operation parameters and structure parameters on the sound pressure distribution in the ultrasonic extraction process was simulated and analyzed.The effects of ultrasonic combined planetary ball milling and ultrasonic combined shearing technology on the extraction rate of hazelnut protein under different extraction process parameters were studied and analyzed.This article proposes a method for extracting hazelnut protein by ultrasonic and mechanical cell wall breaking technology has the advantages of fast,high efficiency,low cost,etc.It provides a new method for plant protein extraction and has good application prospects. |
PDF Full Text Request