An efficient laser sensor system for apple impact bruise volume estimation

Fruit are subjected to several external loads during processes from the orchard to the market, which result in bruising and therefore, quality loss. In this study, we developed a system based on a line laser light source and light detector for a rapid and efficient estimation of the bruise volume of apples (Malus domestica Borkh L. cv. Starking Delicious) dropped from a certain height onto a steel impact plate. We measured two parameters, namely rise time and dwell time, extracted from response signals generated by the proposed system during the impact test. These parameters are related to contact time, showing how long the fruit remains in contact with the impact plate. The experiments were conducted at six different drop heights and two different temperatures. It was found that there was a strong relation with coefficients of determination of more than 0.93 between bruise volume and dwell/rise time, in which the bruise volume decreased with the increasing rise time/dwell time as a power function. Furthermore, the results showed that warm apples developed greater bruise volume than cold fruit, and the estimated regression lines and curves for cold fruit had higher coefficients of determination than those of warmer fruit.     

The effect of drop height on bruising of selected apple varieties

This paper presents an analysis of fruit impact in time and the results of the relationships between the bruise size and various impact parameters. The measuring device allows simultaneously analysis of the three basic quantities: impact velocity, rebound velocity and force response in time, and testing the momentum conservation law for a body such as an apple. In the experiments, the impact velocity 0.25 m s⁻¹ was the maximum velocity at which bruises for all tested apple varieties did not develop. The parameters which were the most strongly correlated with apple bruise volume were maximum force response and dissipated energy, which can be used to predict direct impact effects.     

苹果果实早期发育期间乙烯释放率和过氧化物酶活性的变化

苹果(新红星和金矮生)果实生理落果的早期、后期乙烯释放率较低,其高峰期乙烯释放率较高.果实乙烯释放率与1-氨基环丙烷-1-羧酸(ACC)含量因发育状况不同而不同.生理落果的早期,果实中的过氧化物酶活性较低,高峰期过氧化物酶活性迅速增大.果实不同部位的过氧化物酶(POD)活性及同工酶谱有明显差别.     

Selection of the most efficient wavelength bands for ‘Jonagold’ apple sorting

This paper presents a method based on quadratic discriminant analysis to select the best filters for detecting a wide range of defects in ‘Jonagold’ apple fruit using a multi-spectral vision system. Reflectance spectra of damaged and sound tissue were recorded using a visible/NIR spectrometer. Analysed defects consisted of scald, hail damage (with and without skin perforation), limb rubs, russets, scab tissue, frost damage, rot, visible flesh damage and recent bruises. Camera filter effects were approximated by summing the reflectances of all the wavelengths within the filter bandwidth. Combinations of three and four filters were tested and evaluated for discriminating damaged tissues from healthy ones. If a three-filter combination appeared sufficient to detect most of the damaged tissue, a four-filter combination should be considered for the complete sorting automation of this bicolour apple variety. A fourth filter was necessary to quantify the ratio between the blush and ground colours. Regarding recent bruise defects which represented the major difficulty, an image segmentation algorithm based on local contrast variations can enhance their detection.     

Bruise susceptibilities of ‘Gala’ apples as affected by orchard management practices and harvest date

This study evaluated the influences of irrigation (frequent versus none), crop load (high versus low), and nitrogen (urea fertilizer versus none) on bruise sensitivity of mature apple fruit (cv. Gala) picked on three harvest dates. It includes a proposal for a new index of bruise sensitivity, called specific bruise susceptibility, as an additional tool for studying the effects of management practices on bruising of fresh produce. Results obtained showed that reducing irrigation frequency and practising selective and timely picking of mature fruit offer some potential to reduce fruit susceptibility to bruising. Analyses of the effects of orchard management practices based on specific bruise susceptibility of fruit (mm³ J⁻¹ g⁻¹) suggested that other biophysical fruit properties such as curvature (shape) and maturity status (rather than size alone) may have greater influence on the way in which induced variations in fruit size (e.g. through crop loading and irrigation) respond to mechanical loads during impact bruising.     

Factors that affect tomato bruise development as a result of mechanical impact

External and internal factors that affect tomato bruise susceptibility such as impact- and fruit-related properties were investigated. Logistic regression was used to establish a relationship between tomato loading conditions and the resulting damage. Impact-specific models were built for a more precise determination of the bruise risk related to a narrow range of impact energies, being low (23 mJ), medium (71 mJ), high (158 mJ) and very high (216 mJ) impacts.Pericarp tissue over the locules was much more sensitive to bruise development than radial wall tissue. Tomatoes at room temperature (20 °C) were more sensitive than fruit stored at 12 °C. Tomato susceptibility to bruising increased substantially with ripening and loading conditions. The duration of the impact played a critical role in the bruise development and it is largely determined by fruit intrinsic parameters. Additional effects of the restitution coefficient and the fruit mass were found. Finally, different factors are responsible for tomato bruising in the various impact classes. The effect of low and medium energy impacts is largely controlled by the fruit texture. Especially medium impacts seem to substantially increase the bruise potential. The bruise potential of high and very high impacts mainly depends on fruit ripeness and the location of impact.     

基于幼果期气象数据苹果产量早期预测研究——以运城市为例

本文通过对运城市2005—2018年气象数据和苹果年产量数据进行分析,构建运城市苹果产量早期预测模型。首先,采用HP滤波法将运城市苹果年产量分为趋势产量和气象产量。其次,分别对苹果物候期：发芽期、花期、幼果期、膨果期、成熟期建立多元线性回归模型,研究每个物候期对苹果气象产量影响的强弱。最后,选取对苹果气象产量影响最强的幼果期建立BP神经网络早期预测模型,并对其进行验证。结果表明：选取幼果期建立的BP神经网络苹果产量早期预测模型其预测结果相对平均误差为7.08%,使用2019年相关数据验证BP神经网络产量早期预测模型的精度为89.6%,表明该模型能够较为准确的预测苹果产量,可为农作物产量早期预测提供理论支持。     

Supervised classification of bruised apples with respect to the time after bruising on the basis of hyperspectral imaging data

Apple bruising, as a mechanical damage, occurs due to impact, compression, vibration or abrasion during handling. However, the symptoms of this damage, browning and softening of the tissue, appear not immediately but after a certain period of time after bruising. For sorting and grading systems, the information about how long the bruise exists in affected fruit can be valuable. VNIR (visible and near-infrared) and SWIR (short wavelength infrared) spectral characteristics of sound and bruised apple tissues were analyzed during a two week period after bruising. Supervised classification methods, including support vector machines, linear logistic regression, neural networks and decision trees, were used and compared to check their effectiveness for distinguishing time after bruising with respect to five varieties of apples. The detection system included hyperspectral cameras equipped with sensors working in the visible and near-infrared (400–1000 nm) and short wavelength infrared (1000–2500 nm) ranges. The results of supervised classification revealed good applicability of hyperspectral imaging in VNIR and SWIR spectral ranges for detecting the number of days after bruising. The linear logistic regression neural networks models were found to be the best classifiers in the majority of models developed. Prediction accuracies higher than 90% were obtained for classification models on spectral data pretreated with the second derivative.     

Bruise susceptibility of banana peel in relation to genotype and post-climacteric storage conditions

The aim of this study was to understand the genotypic factors and post-climacteric storage conditions that affect bruise susceptibility of banana peel. Putative physicochemical indicators of bruise susceptibility, including peel electrolyte leakage (PEL), total polyphenolic content, hardness, water content, and peel thickness, were investigated. Bruise susceptibility is the lowest impact energy needed to produce visible bruising by an object dropped on post-climacteric banana fruit from a pre-determined height, converted into impact energy (20–200 mJ with a 20 mJ increment). The bananas were stored either at 18 °C throughout ripening or at 13 °C between the 2nd and 6th day after ethylene induction. Five cultivars with contrasting susceptibility to impact bruises were used. Neither Grande Naine nor hybrid Flhorban925 bruised at the maximum impact energy (200 mJ) during ripening whatever the storage conditions. A gradient in bruise susceptibility was observed among the other cultivars: French Corne > Fougamou > hybrid Flhorban916. Bruise susceptibility increased during ripening and was higher in bananas stored at 18 °C. The lower ripening temperature resulted in a two-day delay to fruit maturity as well as in bruise susceptibility. Bruise susceptibility was positively correlated with PEL (R = 0.78) and to a lesser extent negatively correlated with hardness (R = −0.45), and was not correlated with polyphenolic content. In conclusion, membrane permeability provides the first clue to understanding bruise susceptibility.     

Table olive cultivar susceptibility to impact bruising

Developing mechanical harvesting for table olives will require decreasing fruit damage during harvest and postharvest handling, transport and storage. The susceptibility to bruising and its development over time were studied in three table olive varieties, cv. ‘Manzanilla’, ‘Gordal Sevillana’ and ‘Hojiblanca’. Bruising was produced with controlled energy impacts of 56, 26, 13 mJ. A strong correlation (r² = 0.77–0.90) between bruise volume and impact energy was demonstrated. Bruise susceptibility was higher in the Manzanilla variety, followed by Hojiblanca and Gordal Sevillana cultivars. Bruise time evolution was evaluated using a spectrophotometer for visible and near infrared regions. A bruise index was developed using different wavelengths, 545, 670 and 800 nm. Most darkening due to the browning process happened within 1 h, was exponential and dependent on impact energy level. The discoloration was greatest in the Manzanilla, followed by Hojiblanca and Gordal Sevillana olives.     

基于光谱指数的苹果叶片水分含量估算模型研究

建立快速、无损的苹果叶片水分含量高光谱估算模型,为苹果树干旱预警提供理论依据。以2个不同生育期采集的苹果叶片为研究对象,研究了不同水分含量的苹果叶片高光谱特征,分析了苹果叶片水分含量与光谱指数(WI、WBI、PWI、GVWI、MSI、 NDW)之间的相关关系,建立了苹果叶片水分含量估算模型。结果表明,苹果叶片水分含量的敏感光谱波段主要集中于近红外和短波红外波段;利用6个光谱指数建立的单变量估算模型均达到了极显著水平(P<0.01),但以水分指数（WI）建立的估算模型y=29503x2-57746x+28317的拟合决定系数R2最大,为0.5401;经检验,拟合方程的RMSE为 2.4,RE为 5.8%,检验精度达到了94.2%。采用主成分回归分析方法,建立的苹果叶片水分含量估算模型y=-556.819+347.838x1-17.815x2-27.864x3+299.492x4+25.647x5+9.835x6的拟合决定系数R2为0.6371,经检验,拟合方程的RMSE为 1.26,RE为 1.8%,检验精度达到了98.2%。表明以主成分回归分析建立的苹果叶片水分含量估算模型具有较好的敏感性和稳定性。     

苹果MdCaM的克隆及其对果实采后非生物胁迫的响应

为解析苹果钙调蛋白基因MdCaM在非生物胁迫过程中的功能.以秦冠苹果为材料,克隆了苹果MdCaM基因,并利用MEGA 5.0软件对其编码的蛋白进行了聚类分析,利用qPCR分析了MdCaM在采后损伤、低氧、高温等胁迫条件下的表达模式.结果表明,不同物种间钙调蛋白具有较高的同源性,MdCaM与拟南芥的钙调蛋白CaM1基因关系较近;qPCR结果表明,MdCaM在损伤、低氧胁迫(0 O2或3％ O2)后均呈先升高后恢复正常水平的表达模式,损伤后6h达到峰值,低氧(0 O2)处理1h后达到峰值;高温(20℃/40℃)诱导后其表达量高于同期对照组,并在处理后12 h达到峰值,表明该基因可能参与了高温胁迫下的全程响应.因此推测,MdCaM基因可能在苹果适应损伤、高温、低氧等逆境胁迫过程中发挥重要作用,可能参与了苹果生长发育过程中的逆境调控.为后继研究MdCaM的功能和作用机制奠定基础.     

追施氮肥对小黑麦光合特性的影响

对施肥处理后小黑麦（中饲237）的光合指标及其相互关系进行研究。结果表明,抽穗后旗叶叶绿素总量Chl(a+b)变化为双峰曲线,第一峰出现在孕穗期,第二峰出现在灌浆期。且施肥处理叶绿素含量在各期均大于未施肥的处理。净光合速率PN的最大值都出现在抽穗期左右,并且所有的处理都从拔节期到抽穗期逐渐增加,然后持续下降。而对照则是从拔节期到抽穗期逐渐下降,之后保持相对稳定直到孕穗后期。然后才逐渐下降。从整个生育期来看, A5蒸腾速率的峰值出现在拔节盛期,而其他都出现在抽穗后期。整体趋势是逐渐下降的。     

基于复杂性测度的柑橘病虫害识别

为进行柑橘病虫害的机器识别,提出了柑橘病虫害为害状特征的复杂性测度表达与病虫害识别方法。首先,对柑橘病虫害为害状主要色调区间[0,120°]进行长度为1°的等分割,形成120个色调子区间;其次,统计各色调子区间像素分布密度,以此作为柑橘病虫害为害状复杂性测度的结构性序列;再次,依据此结构性序列计算病虫害为害状统计复杂性测度,并将其作为病虫害特征值;最后,将Shannon信息熵和统计复杂性测度作为输入变量建立3层前馈神经网络柑橘病虫害识别模型来识别柑橘病虫害。柑橘蓟马、褐圆蚧、柑橘树脂病、糠片蚧各30个测试标本最低正确识别率、最高正确识别率、平均正确识别率分别为93.3%、96.7%、95%。试验结果表明,柑橘病虫害为害状的复杂性测度较充分地表达了柑橘病虫害的典型特征,能用此方法进行柑橘病虫害识别。     

鲜切苹果保鲜技术研究进展

鲜切苹果是一种即食的新型苹果加工产品,具有方便快捷,营养价值丰富的特点,满足了现代社会快节奏生活需求,但其与未经加工的新鲜苹果相比,在贮存时更易发生品质方面的问题。阐述了引起鲜切苹果酶促褐变、水分和营养物质流失、微生物滋生以及组织软化问题的机制及国内外研究进展,并将现阶段的鲜切苹果保鲜技术从物理、化学和生物三方面进行分析总结,对其未来研究方向进行展望,旨在为鲜切苹果保鲜技术的进一步发展和应用提供参考。     

插装式电液比例流量放大阀特性分析

插装阀具有通流量大、结构简单和成本低等优点,广泛应用于液压系统中。笔者针对一种主级基于流量放大原理、先导级采用单级伺服比例方向阀的两级插装比例节流阀特性进行分析,建立了该比例节流阀的简化数学模型,获得了简化条件下的特性关系式。以此为基础,在SimulationX软件环境中建立该液压阀的仿真模型,利用实验数据对模型正确性进行验证,运用验证后的仿真模型对比例阀性能特性进行分析。结果表明：该液压阀输出流量静态特性存在死区,阶跃响应存在时间滞后,主阀流量放大倍数并不是常数,性能影响因素与主阀反馈槽预开量、面积梯度、级间过渡容腔体积以及先导阀通流能力等相关。     

新世纪以来延安苹果花期冻害影响分析

利用2001年以来延安出现的5次苹果花期冻害天气过程,通过对比分析温度、花朵受冻率和产量,得出：延安市苹果花期冻害有日期提前和影响加重的趋势;严重冻害年具有温度通过0℃初日早、3月温度明显偏高、积温高的特征;不同物候期形成冻害指标不一样,整个花序受冻指标,在中心花开放期和花序分离期,过程极端最低气温在-3℃左右时,少量中心花受冻, 最低气温≤-4 ℃会形成轻度受冻,最低气温≤-5 ℃出现中度受冻。盛花期当温度降至-3 ℃时出现轻度受冻;-4 ℃时出现中度受冻;-5 ℃度以下时,重度受冻。今后花期冻害天气的预报及影响评估,既要考虑冻害过程最低温度值,也要重点考虑通过0℃初日、3月温度与活动积温情况,前期气温是否异常偏高等现象。     

苹果品质近红外光谱无损检测技术研究进展

近红外光谱(NIRS)分析技术以其快速、无损、多组分同时测定及可在线分析等优势,近年来在苹果品质无损检测应用技术的研究方面取得了重要进展。本文介绍了NIRS分析技术的原理与特点,从苹果品质的定量与定性分析、在线检测及便携式检测等方面综述了国内外NIRS在苹果品质检测中应用的研究进展,并对其应用前景进行了展望。     

苹果MicroRNA的茎环RT-PCR检测及离体试管苗与田间苗表达差异

MicroRNA(miRNA)在植物的生长发育过程中起着重要作用。以改进CTAB法提取的总RNA为模板,通过设计茎环反转录引物,利用定性RT-PCR技术从寒富苹果幼嫩叶片、成熟叶片、嫩茎、幼果和根等不同器官中均检测到miRNA,并从寒富苹果叶片中克隆分离出14种miRNA。在此基础上利用半定量RT-PCR技术对寒富苹果离体试管苗与田间苗中10种miRNA的表达差异进行分析,结果发现,miR156和miR157在离体试管苗叶片中表达量明显高于田间苗幼叶。本研究建立了苹果miRNA的茎环RT-PCR检测体系,为研究miRNA在苹果植株生长发育过程中的作用奠定了基础。     

Acidity and sweetness in apple and pear

Summary Sweetness and acidity in apple and pear inherit independently and can be organoleptically evaluated separately, but less accurately in pear than in apple. For breeding purposes an analysis of fruits for acidity and sweetness with pH indicator paper and a hand refractometer is to be prefered to the organoleptic method.In apple, the acidity-decreasing with time-of the unripe fruit was already strongly indicative of that of the eating-ripe fruit; sugar-increasing with time-not before the fruit was picking ripe. Sugar content in apple and pear, and the pH in pear, appeared to be normally distributed; the pH in apple showed a segregation into an acid and a low-acid group, which occurred in both the unripe and ripe stage. The segregation ratio between these groups was found to be highly variable. On the whole, the mean acidity and sugar content of apple and pear progenies is significantly determined by that of the parents. Most of the observations made did not support the theory that low acidity in apple is determined by one recessive gene. The relationship between the pH of leaf juice and fruit juice in apple may offer a possibility for pre-selection.