Numerical Characterization Of Sugar Content Of Aksu Apple Based On Electrical Characteristics

Aksu is red Fuji apple varieties is southern xinjiang characteristic fruit industry,due to taste sweet,stone Chu Jie "rock candy hearts" organization and consumers,the market price is significantly higher than without Lizzie apple,Lizzie call Lizzie degree,degree of organization of Lizzie degree different caused apple quality index differences,directly affect the sales price of the aksu apple,Numerical characterization of apple sugar content is an important engineering problem urgently to be solved in Aksu Apple industry.It is of great engineering significance to explore the correlation between the sugar content and quality indexes of Aksu apples and numerically characterize the sugar content of apples,which can provide theoretical guidance for the classification of apples after harvest and promote the development of Apple industry in Aksu and increase the income of fruit farmers.Taking the effect of sugar content on quality index and electrical parameters of apple in Aksu as the research objective,the relationship between sugar content and quality index of apple was explored.The nondestructive testing method based on electrical characteristics was introduced to study the changing rule of apple electrical parameters with sugar content,and the mathematical model of the relationship between electrical parameters and sugar content of apple was established.The optimal electrical parameters and the combination of test frequency were determined based on Critic weight method,and the sugar content of Aksu apple was numerically characterized.The main conclusions of this study are as follows:(1)Revealed the changing rule of quality index of Aksu apple with picking period and the relationship between quality index and sugar content.During the whole picking period of Aksu apple,apple samples were divided into super grade,first grade and second grade according to fruit diameter.Fruit weight per fruit,difference between red and green a*,soluble solid SSC and total sugar content of three different apple quality indexes showed a gradually increasing trend with the extension of picking time.Brightness L*,yellowish blue difference B *,hardness and total acid all showed a decreasing trend with the extension of picking time.The sugar content of apples of three different grades increased gradually with the extension of picking time,which was second grade > first grade > super grade.There was the highest correlation between total sugar of super fruit and apple sugar degree,the highest correlation between hardness of first fruit and apple sugar degree,the highest correlation between L* of second fruit and apple sugar degree,and there was a significant correlation between fruit quality indexes of all levels.(2)The variation of electrical parameters of Aksu apple with quality indexes was investigated.The values of parallel equivalent capacitance Cp,series equivalent capacitance Cs,loss factor D and complex impedance Z and the saccharicity of three different grades of Aksu apple showed an increasing rule,which showed that with the increase of saccharicity,the values of Cp,Cs,D and Z of electrical parameters increased.The phase Angle θ of electrical parameters and the degree of saccharicity decrease gradually at first and then sharply,which shows that θ decreases with the increase of the degree of saccharicity.The Cp,Cs and Z values of electrical parameters decrease gradually with the increasing of test frequency.The electrical parameters D and θ decrease first and then increase with increasing test frequency.(3)A numerical method was proposed to characterize the sugar content of Aksu apple based on electrical characteristics.The mathematical models of the sugar content and electrical parameters of aksu apples were quadratic functions,and the values of Cp,Cs,D,Z and θ of electrical parameters could effectively represent the sugar content of Aksu apples.The electrical parameters and test frequency were optimized based on Critic method.The results showed that the Cs value of electrical parameters was the best to characterize the sugar content of aksu apple when the test frequency was 100 Hz.This study can provide theoretical guidance for numerical characterization of sugar content of Aksu apples and grading of apple quality after harvest.