【作者】 戴炜；

【导师】 郭康权；

【作者基本信息】 西北农林科技大学 ， 农产品加工及贮藏工程， 2008， 硕士

【摘要】 随着果品产业的飞速发展,果品品质越来越受到果农、果商和消费者的重视,也为品质检测提出了更高要求。本文通过研究苹果微弱光特性的变化,探讨利用微弱光无损检测技术来判断苹果内部品质的方法。本文以富士苹果为对象,利用单光子计数探测系统,研究了测试条件、预处理方法、等因素对苹果超微弱光特性参数的影响;通过大量试验,初步探究了苹果在储藏阶段的超微弱光值变化与内部品质的关系;研究了不同损伤条件下苹果微弱光特性的变化。得到以下研究结论:1.苹果超微弱发光(UL)与照射光源的种类、照射强度、照射时间、距离等测试条件有密切关系。果实的超微弱发光值随时间延长而衰减,用双指数曲线可以较好地拟合苹果的微弱光随时间的衰减关系;光强越强,时间越长,UL值越大;白炽灯照射比荧光灯照射苹果的UL值大,光源照射距离对UL值的影响不显著。2.苹果品种、生长位置、成熟度、测试部位、温度等因素影响苹果超微弱发光特性。暗室贮藏比在正常环境下UL值要高;温度越低,UL越小;早熟品种的UL高,晚熟品种较低;赤道与果蒂处的UL值低,果梗处的UL值高;树冠顶部苹果的UL值最大,中部次之,底部最弱,树冠南面和西面的UL值大,东面次之,北面最弱;随着果实成熟度增加,其UL值下降。3.新鲜苹果的糖度、酸度、硬度、可溶性固形物含量、pH值等品质指标与超微弱发光的关系不显著。4.苹果贮藏期的超微弱光变化显著。果实在采后成熟过程中超微弱发光有明显的峰值出现;随着贮藏时间延长,UL值不断减少;随着苹果硬度下降、pH值下降、可溶性固形物缓慢增加,其UL值下降,利用微弱光值的大小可以判断苹果新鲜度等级。5.破损对称苹果超微弱光值有明显影响。损伤瞬间,苹果的超微弱光值急剧变化;撞击损伤果的微弱光值随时间变化明显,静压损伤果随时间变化不显著;损伤面积较大以及损伤深度较大的果品,UL值变化明显;储藏期间,损伤苹果的UL值持续降低,无损苹果的UL则变化的非常缓慢,利用微弱光值的大小可以判断苹果损伤。更多还原

【Abstract】 With the rapid development of the fruit-industry, the quality of fruits has been attached more and more importance to fruit farmers, fruiterers and consumers. And this asks for the higher standard for the examination of fruits. In this article, we use the nondestructive determination technology to judge the characteristics of apples by studying the change of the ultra weak bioluminescence(UL) parameters of apples.This paper aimed to Fuji apple, using single photon counting testing system, studying infection of the ultra weak bioluminescence(UL) parameters of apples, such as test conditions, pretreatment methods, types of fruit etc; We also studying the relationship between the ultra weak bioluminescence(UL) and the physical character during the storing by lots of experiments; We studying changes in the the ultra weak bioluminescence(UL) of Apples by different injury condition. The result shows:1. Apple’s ultra weak bioluminescence(UL) and the type of source, the radiation intensity, exposure time, distance test conditions closely related. The ultra weak bioluminescence of apples decay with time, and with double exponential curve fitting can be used to Apple’s UL attenuation relationship with the passage of time. The stronger light intensity, the longer the time, the greater the UL value; incandescent light have more affection than fluorescent radiation light on apple’s UL value. The distance of light irradiation impact on the UL is not significant;2. Apple varieties, growth position, maturity, test location, temperature and other factors affect Apple’s ultra weak bioluminescence(UL) properties.UL of apple stored in the darkroom is higher than in the normal environment; the less temperature, the lower UL of apples; Early apples’UL higher than late-maturing; UL of guandi and the equator are lower ,UL of luogeng is higher. UL of Apple growing top is largest, followed by Central, at the bottom of the weakest; apples growing in the south and west of the tree, the higher UL value, east of the second, north is the lowest.;As the fruit matured, its UL value decline.3. The relationship of fresh apple’s ultra weak bioluminescence(UL) properties and quality indicators ,such as sweetness, acidity, hardness, soluble solids content, pH value, is not significant. 4. During the storage, significantly the ultra weak bioluminescence peaks appear, and UL decreased as the extension of storage time. with the decline in Apples’hardness, PH value decline, the slow increase in soluble solids, UL value also declining UL value can be used to judge Apple fresh grade.5. Damage affect Apples’UL value obviously. UL value changed distinctly at damaging moment. UL of damaged Fuji apples changed sharply in storage period, and UL of pressed apples is not significant.The larger area and the deeper of the damages are more remarkable of UL value changes. During storage period, UL of damaged apples reduce rapidly, undamaged apples’UL change slowly. As a new method, UL can distinguish damaged apple from undamaged.更多还原