Studies Of The Correlations On Shell Structures And Nut Qualities Of Walnut

Walnut includes shell and kernel, the latter is popular because of abundant nutrition, but the former is not attached importance. The experiment carried the roundly systemic studies on the shell structures of walnut by designing and using the special apparatus; probed the correlations of the shell structures and nut qualities. The purpose was supplying a scientific means for correctly assessing the walnut quality, a scientific foundation for selecting improved cultivar and culturing of walnut. The main results were as follows:1. The shell structure indexes (shell seal grade, mechanical strength, density of shell, shell thickness and volume of shell cell) had obvious correlations with the rate of wormed nut, the stain rate and the rate of dissilient nut. The shell seal was tighter, the rate of wormed nut, the stain rate and the rate of dissilient nut were littler, and the shell structure was one of the important characters of walnut. The fitting range of shell seal grade was 130-370N.2. The experiment proposed kernel weight per centimeter for the first time, and thought that kernel weight per centimeter was more visual and exact than kernel ratio to show the full degree of walnut through the correlation analysises on kernel weight per centimeter with kernel ratio and per nut weight.3. The shell structure indexes had distinct difference among different cultivars, between ordinary walnut (Juglans regia L.) and Tie walnut (Juglans sigillata Dode.), among the same cultivars of different places of production. So the cultivar, climate, soil and so on were the key factors that affected walnut shell structures.4. With Hearing the harvest, the shell seal grade of walnut descended, the mechanical strength and density ascended, but the shell density descended in 1 week before harvest.5. Different fat physiology and biochemistry indexes correlated with the shell structures definitely, in which the acid value and MDA content had the notably negative correlation with the shell seal grade, the MDA content had the positive correlation markedly with volume of shell cell.6. There were obvious correlations between the kernel colour and shell structures (density of shell, shell thickness, shell seal grade, volume of shell cell, rate of wormed nut and stain rate), nut qualities (hexadecylic acid content, stearic acid content, kernel weight per centimeter, kernel ratio).7. The kernel became sour more and more badly along with the storage stage prolonging. The becoming sour of kernel fat ,in cold storage was lower obviously than in the room temperature storage. The fat physiology and biochemistry indexes and fatty acidcontents of different cultivars were all distinct. The fat physiology and biochemistry indexes obviously correlated with the unsaturated fatty acid contents. The linoleic acid content was high, iodine value was high, and the fat easily happened the oxygenation and deterioration.8. Rate of respiration of walnut closely correlated with the water content of nut, the rate of respiration was low more and more with nut losing water and storage stage prolonging, rates of respiration of different cultivars had biggish difference in 20 days after harvest; but 20 days later (after water contents not changing) the rates of respiration were accordant basically, and there were not obvious changes in the storage.