Investigation Of High Oil Walnut Resources And Study On Evaluation System Of Oil Walnut

Walnut(Juglans regia)is one of the four major nuts in the world,and is also the world's largest economic forest species.The planting area of walnut in China has reached 100 million mu,close to 50% of the world.However,the rapid increase of planting area has led to a gradual reversal of the relationship between supply and demand of walnut,and the price and economic benefits have been declining.Even in some areas,walnut trees have been cut down because of losses.At present,walnuts are directly eaten as nuts or processed into protein beverages/protein dew in walnut industry.However,walnuts with poor taste and high oil content(high oil)lack market competitiveness and are gradually eliminated by the market,especially in mountainous areas,walnut resources with high oil content(high oil)are decreasing day by day.Therefore,transforming high-oil walnut resources into oil walnut to form high-quality walnut oil products is one of the key to solve the dilemma of walnut industry in China.Based on this,this paper intends to establish a preliminary evaluation system of oil walnut through the investigation of high-oil walnut resources,and provide a resource basis and scientific basis for the development and utilization of oil walnut resources in China.The main results are as follows:1.Determination and variation of oil production and nutritional quality of high-oil walnut resources.The single fruit weight,kernel yield,oil content,trace elements,soluble sugar,soluble protein,fatty acid and flavor substances of walnut were systematically analyzed by ICP/MS,GC/MS,physiological and biochemical techniques and methods.The results showed that the single fruit weight of walnuts was mainly between 10 g and 14 g,which was the common weight of walnuts.The average kernel yield was about 50%,but it was as high as 55.29% in No.17 area.In terms of oil content,the average oil content of walnuts outside Henan Province was higher than that of walnuts inside Henan Province.In terms of elements,the contents of beneficial elements in walnuts in Henan Province are higher than those outside Henan Province.The total contents of elements in No.1,No.2 and No.3 areas are better as a whole,and all harmful elements are within the scope of the national standards.In terms of soluble protein,the content of soluble protein in walnuts in Henan Province is generally higher than that in other provinces,cities and regions,and the content in No.3 area of Henan Province is higher than in other areas,the trend of soluble sugar content is different from that of soluble protein,which is generally higher outside Henan Province than in Henan Province.In terms of fatty acids,the content of unsaturated fatty acids is as high as 90%,of which linoleic acid content is 45.11%-68.15%,linolenic acid content is 5.53%-13.67%.In terms of flavor substances,the tocopherol content in areas 2,3,13 and 18 is higher,No.1.The content of beta-sitosterol in No.2,No.3,No.14 and No.18 areas was higher than that in other areas.2.Establishment of evaluation model of walnut resources for oil use.A mathematical model for evaluating walnut oil production was established,in which x1=walnut kernel yield,x2=oil content of walnut kernel,x3=fatty acid composition of walnut oil(unsaturated fatty acid/saturated fatty acid),x4=single fruit weight of walnut.According to the influence factors of each index on final oil production,the mathematical model of walnut oil production evaluation system was obtained by comprehensive calculation: Y=0.45y1 + 0.35y2 + 0.12y3 + 0.08y4 = 32.3136x1 +29.97855x2 + 0.1711468x3 + 0.093344x4-33.235198.A mathematical model for evaluating nutrient quality of walnut kernels were established,including M1=soluble protein content of walnut kernels,M2=soluble sugar content of walnut kernels,E=beneficial elements content of walnut kernels,F=flavor substance content of walnut kernels,S=harmful elements content of walnut kernels(heavy metal content exceeding national standards does not participate in the calculation of this formula).The final regression equation for nutrient quality evaluation of walnut kernels was P=0.4M1+0.4M2+0.355E+0.35F-0.5S.3.Classification of walnuts in different regions according to the evaluation model.In the oil production evaluation system of walnut resources in 18 regions,there are two areas with evaluation grade A,which are No.2 region and No.14 region,which are very good oil-producing walnut resources.There are 12 areas with evaluation grade B,which are better oil-producing walnut resources.In the evaluation system of nutrient quality of walnut kernels,the area No.1 with evaluation grade A is very good,while the area with evaluation grade B is 6,and the nutrient quality of walnut kernels is better.Establish the evaluation grade of double A oil walnut resources for oil production and nutrient quality.Walnut resources in No.2 area are the best,followed by walnut resources in No.1 area.