Study On Effects Of Bagging On Cuiguang Pear Fruits

Cuiguan pear was one of sand pear cultivar widly planted in south of China withgood quality of early-maturing. The yielding acreage is more than 70, 000 hm~2. the goodquality are early-maturing, bigger shape, good flavour, fewer stone cell. The shortcomingis easy to form rusty stain on the pericarp and result in fruit appearance quality is notexcellent, which restricted development of Cuiguan pear. Bagging is a vital solution toimprove sand pear's appearance quality. But, the research of bagging technology doesnot perfect at present, threr are a lot of problems remaining to be solved in theapplication producing practice. Consequently, this experiment studied the effect ofbagging on quality of pear using Cuiguan as material by means of different paper bagtypes and different bagging time. The results were as follows:1. Bagging could significantly improve the appearance quality of fruits. There wereinconsistent patterns of improving fruit appearance quality between this study and others.The others reported the appearance quality were improved with bagging by decreasingthe rusty stain. We improved the fruit appearance quality by bagging with increased rustystain, then improved smoothness and reduced the contents of pericarp pigment. Rustystain, smoothness, colour and lustre were important for Cuigguan pear. A good qualityfruit requires fruit are full of rusty stain, highly polished and fruit bottom colour areyellow white. The double bag layers with more than one black layer can reduce thecontents of pericarp pigment, remove the green disturbance to brown rusty stain andimprove the apperance quality. In this study, the double layers bag with"grey-black-black-black" made by Dafudi corporation of Zhejiang province and "Frenchgrey-black-yellow-yellow" made by paper mill of Laiyang of Shandong province werethe best bagging during 35～40 d after withering.2. The rusty stain of fruit was increased and smoothness of fruit was improved bybagging. There were significant differences in different bags. The average rusty stainindex in the bags made by Dafudi corporation of Zhejiang province and paper mill ofLaiyang of Shandong province increased by 35.6% and 34.2%, smoothness indexdecreased by 96.6% and 95.8% in comparation with CK. Respectively, These resultsindicated that, with the date of bagging being delayed, the rusty stain index showsupward tendency. There is significant positive relationship between bagging time and therusty stain index (r=0.41).3. Pigment in pericarp was decreased significent by bagging. The minimum contentsof chlorophyll a, chlorophyll b, carotenoid and flavonoid decreased by 85.0%, 78.5%, 71.1% and 54.6%, respectively. There appeared to be significant positive relationshipbetween pigment contents in pericarp and tansparency of bags. The correlationcoefficient between the tansparency of bags with chlorophyll a, chlorophyll b, carotenoidand flavonoid were 0.851, 0.364, 0.766 and 0.343.4. There were consistent patterns in tansparency of bags in visible wavelength(420～780 nm). It appeared to be hyperbola, approximately. In wavelength of 430-700 nm,variation of bag's tansparency presented a significently three-level parten curves withdifferent bag on different level curves. Tansparency of bags increased significantly after700nm of significantly. Variation of bag's tansparency was on the lowest level patern ifthe bag be with one or more than one layers of black paper. The most efficientwavelength of bag's tansparency on pigment contents in pericarp is 510-700 nm.5. The peel thickness was increased by bagging. For bag type trentments, there were6 types bag significant increased peel thickness, 1 type bag decreased peel thickness and4 types bag had no significant differences compared to CK. For time treatments, the peelthicknes incresed by 6.3% in the first time by bagging compared to CK, and there wereno significant differences between later treetments compared to CK.6. The contents of soluble solid and soluble sugar would decreased through bagging.The contents of soluble solid and soluble sugar was the lowest on May 4 and significentlower than other treatments and CK, it decreased by 12.6% and 21.4% in comparation toCK, respectively. There were no significant differences between other time treatments(May 9, 14, 19, 24), but all significent lower than CK.Finally, we advanced a new notion by increased the rusty stain to improve appearancequality, and fotmd two type of bags which have significant improve Cuiguan pearappearance quality, which is very useful.