The Structure Observation And Component Analysis Of Apple Fruit Epicuticular Wax

In this study,we have improved a brief and effective sample preparation method forscanning electron microscope to observe the epicuticular wax of ‘Honeycrisp’ apples,and alsoestablished a method for extracting epicuticular wax of ‘Honeycrisp’ apples. Based onmethods above, we isolated and identified the epicuticular wax of ‘Honeycrisp’ and ‘Gala’apples.What we have done was expected to offer Reference for researching the relationshipbetween epicuticular wax and storage characteristics of apples.The results were as follows:（1） Compared with removing water by immersing samples into defferent concentrationsof organic solvent,the time for preparation was compressed from24h to5h by freezedrying.There were5steps for fomer preparation:fixing, dehydration with organic solvent.processing with isoamyl acetate, Supercritical drying, being coated with platinum. Now onlyfreeze drying and being coated with platinum were needed.（2） When the sample size was5, apples were immersed into300ml chloroform for threetimes and45seconds every time, the epicuticular wax could be extracted completely. Withnumber of apples rising, the epicuticular wax of apple fruits could be eluted completely for3times instead of1or2times by chloroform. Now the time and the amount of chloroform wehad exhausted was less than the ones reported and the method we got was much moreefficient and convenient and could be referenced when extracting epicuticular wax of otherfruits.（3） The componets of defferent polarity extracted from epicuticular wax of ‘Honeycrisp’and ‘Gala’ apples coud be separated effectively by column chromatography. Alkane and fattyacid were main components. N-alkanes kept odd predominance and fatty acids kept evenpredominance. There are some differences on the components between the two varieties.Thealkanes of nC₁₆, nC₁₇, nC₃₂and nC33were not found in epicuticular wax of ‘Gala’ apples, butfound in the one of ‘Honeycrisp’ apples. The saturated fatty acids with16carbon centres weremost strongly represented in ‘Honeycrisp’ apples, but the unsaturated fatty acids with18carbon centres were most strongly represented in ‘Gala’. The differences which there wereonly6kinds of esters were found in both of the two varieties were most strongly showed.