Micromorphology of cactus-pear (Opuntia ficus-indica (L.) Mill) cladodes based on scanning microscopies

Cladode ultrastructural features of two prickly and two spineless Opuntia ficus-indica cultivars were examined using environmental scanning electron and atomic force microscopies. Observations focused on cladode as well as spine and glochid surface micromorphologies. Prickly cultivars were characterized by abundant cracked epicuticular wax deposits covering the cladode surface, with an amorphous structure as observed by AFM, while less abundant waxy plates were observed by ESEM on spineless cultivar cladodes. Further AFM observations allowed a rough granular and crystalloid epicuticular wax structure to be distinguished in spineless cultivars. Regarding spine micromorphology, prickly cultivars had strong persistent spines, observed by ESEM as a compact arrangement of oblong epidermal cells with a rough granular structure. However, deciduous spines in spineless cultivars had a broken transversely fissured epidermis covering a parallel arrangement of fibres. Through AFM, the deciduous spine surface presented an irregular hilly and smooth microrelief while persistent spines exhibited rough helical filamentous prints.ESEM and AFM studies of cladode surfaces from prickly and spineless cactus pear cultivars revealed valuable micro-morphological details that ought to be extended to a large number of O. ficus-indica cultivars.     

大果水晶梨与其褐色突变体多酚氧化酶及过氧化物酶同工酶差异(简报)

大果水晶梨果皮为绿色,2007年在其植株上发现一果实呈褐色的变异枝,经2008-2009年嫁接试验后确定为遗传性变异。与原品种比较,褐色突变体果实多了一层褐色木栓层。     

苦瓜杀虫及抑菌活性组分物质的制备

采用生化方法从苦瓜种子中提取得到苦瓜籽油、凝集素备提物、苦瓜籽粗蛋白和苦瓜凝集素4种活性组分,其中凝集素备提物、苦瓜籽粗蛋白和苦瓜凝集素得率分别为:2.16%、3.06%、0.37%。旨在寻找苦瓜中有效杀虫及抑菌活性物质。     

白藜芦醇对砀山酥梨的保鲜效应

文章以砀山酥梨果实为试材,在果实冷藏(2士0.5℃)前,采用0.5μL·L-1白藜芦醇溶液浸泡2 min,定期对果实保鲜过程中相关的生理指标进行测定,在贮藏后期对梨的黑皮病发病情况做统计,研究白藜芦醇对砀山酥梨果实采后保鲜效应和黑皮病的抑制及可能发病机理.结果表明:白藜芦醇处理对砀山酥梨有较好的保鲜效果,可抑制共轭三烯的含量、增加细胞的膜透性、降低α-法尼烯的峰值,显著抑制和延缓梨果实在贮藏期和货架期黑皮病的发生.     

Valorization of Bio-Residues from the Processing of Main Portuguese Fruit Crops: From Discarded Waste to Health Promoting Compounds

Food processing generates a large amount of bio-residues, which have become the focus of different studies aimed at valorizing this low-cost source of bioactive compounds. High fruit consumption is associated with beneficial health effects and, therefore, bio-waste and its constituents arouse therapeutic interest. The present work focuses on the main Portuguese fruit crops and revises (i) the chemical constituents of apple, orange, and pear pomace as potential sources of functional/bioactive compounds; (ii) the bioactive evidence and potential therapeutic use of bio-waste generated in the processing of the main Portuguese fruit crops; and (iii) potential applications in the food, nutraceutical, pharmaceutical, and cosmetics industries. The current evidence of the effect of these bio-residues as antioxidant, anti-inflammatory, and antimicrobial agents is also summarized. Conclusions of the revised data are that these bio-wastes hold great potential to be employed in specific nutritional and pharmaceutical applications.     

Optimized prediction of sugar content in ‘Snow’ pear using near-infrared diffuse reflectance spectroscopy combined with chemometrics

In near-infrared spectroscopy applications, the original spectra often contain redundant information, which will seriously affect the performance of chemometric models. Therefore, preprocessing, effective wavelengths selection, and appropriate regression models are essential. The objective of this study was to optimize the nondestructive determination multivariate calibration model of sugar content in ‘Snow’ pears, using near-infrared diffuse reflectance spectroscopy combined with chemometrics. All data (sugar content reference values and spectra data) from three measuring positions (P1, P2, and P3, marked around the pear’s equator at angular distances of approximately 120°) were divided into four grouped datasets, namely Set-1 (P1), Set-2 (P2), Set-3 (P3), and Set-4 (average of the three measuring positions). All subsequent optimized processes were performed based on each grouped dataset. First, different preprocessing methods were tested and an optimal method was determined. Then, synergy interval partial least squares and synergy interval partial least squares-competitive adaptive reweighted sampling were applied to select effective regions and effective wavelengths from all wavelengths, respectively, and partial least squares regression models were established and analyzed. In addition, support vector regression models were also established for comparative study. After comprehensive analysis of prediction accuracy and model complexity, the partial least squares regression model based on the 16 selected effective wavelengths for Set-4 was optimal, with the correlation coefficient for prediction, root-mean-square error of prediction, and residual predictive deviation of 0.9701, 0.2311, and 4.12, respectively. The results indicated that with these optimized processes, the multivariate calibration model of sugar content in ‘Snow’ pears was effectively optimized for each dataset. In addition, it is concluded that partial least squares regression was superior to support vector regression in this study, although some other researches had found different results in related fields.     

超高压处理对多酚氧化酶活性的影响

 研究了超高压中温协同处理对砀山梨汁中多酚氧化酶活性的影响,实验压力为0.1~500 MPa,温度为20~60 ℃。此外,考察了不同pH值（3~7）和保压时间（2~34 min）超高压处理对酶活性的影响。实验结果分析表明：在处理温度为50 ℃、保压时间为10 min和梨汁pH值为5的条件下,200~300 MPa处理梨汁时多酚氧化酶被激活,活性表现最高;500 MPa时酶的活性下降到75.3%。协同温度为30 ℃处理梨汁时,酶的活性反而增大;30 ℃以后,酶活性随温度升高而迅速降低;有效协同高压处理的温度为40 ℃。随着保压时间的延长,梨汁中过氧化物酶的活性减小;18 min以前下降速度较快些,之后下降速度变缓。pH在5~6之间,酶的残留活性最大;pH值为6时,梨汁中多酚氧化酶最为耐压。     

不同水肥管理对梨枣叶片生理生化指标的影响

采用不同水肥管理测定了梨枣叶片中的叶绿素含量、净光合速率、可溶性糖含量、可溶性蛋白质含量的变化。结果表明:与对照相比,不同水肥处理下,均能显著提高梨枣叶片中叶绿素含量、净光合速率和可溶性蛋白质含量,其中,浇灌完全营养液还能显著提高梨枣叶片中的可溶性糖含量,表明适当水肥处理对梨枣叶片的生长代谢具有促进作用,其中浇灌完全营养液的效果最好。     

基于近红外光谱分析技术测定库尔勒香梨硬度

采用近红外(NIR)漫反射光谱法对新疆特色梨果库尔勒香梨的五种不同果（包括青头、粗皮、脱萼、宿萼、突顶果）的硬度进行测定。由于近红外光谱数据量大且原始光谱噪声明显、测定水果时散射严重等导致光谱建模时关键波长变量提取困难。以新疆库尔勒香梨为研究对象,为了有效地消除固体表面散射以及光程变化对NIR漫反射光谱的影响,首先采用标准正态变量变换（SNV）和多元散射校正（MSC）对库尔勒香梨的原始光谱进行预处理。为寻找适合近红外光谱检测库尔勒香梨硬度的最佳特征波长筛选方法,进行香梨近红外光谱的特征波长变量选择方法的比较与研究。研究比较了两种特征波长筛选方法对库尔勒香梨硬度偏最小二乘法（PLS）建模精度的影响。同时使用反向偏最小二乘（BiPLS）和遗传算法结合反向偏最小二乘（BiPLS-GA）在全光谱范围内筛选香梨硬度的特征波长变量,将校正均方根误差（RESMC）、预测均方根误差（RESMP）以及决定系数（R2）作为模型的评价标准,并最终确定最优波段选择方法及最佳预测模型。基于选择的特征波长变量建立的PLS模型（BiPLS-GA）与全光谱变量建立的PLS模型进行比较发现BiPLS-GA模型仅仅使用原始变量中6.6%的信息就获得了比全变量PLS模型更好的库尔勒香梨硬度的预测结果,其中R2,RMSEC和RMSEP分别为0.91,1.03和1.01。进一步与基于反向偏最小二乘算法（BiPLS）获得的特征变量建立的PLS模型比较发现,BiPLS-GA不仅可以去除原始光谱数据中的无信息变量,同时也能够对共线性的变量进行压缩去除,使得建模变量从301个减少到20个。极大地简化模型的同时有效地提高了模型的预测精准度和稳定性。因此该方法能够有效地用于近红外光谱数据变量的选择。证明了近红外光谱分析技术结合BiPLS-GA模型能够高效地选择出建模变量,去除与库尔勒香梨硬度无关的近红外光谱信息,显著地提高库尔勒香梨硬度定量模型的预测精度。这不仅为新疆地区特色梨果库尔勒香梨的快速、精确、无损优选分级提供一定的技术支持,同时也为基于近红外光谱分析技术预测水果内部品质的研究提供了参考。     

不同红梨品种果实中营养元素含量的光谱测定

用火焰原子吸收光谱法对美人酥、红酥脆和满天红3个红梨品种果实中K,Fe,Zn,Ca,Cu,Mg和Mn七种营养元素含量进行了测定分析。各元素在实验范围内,线性关系良好,回收率在98%～104%之间,结果较为满意。3个红梨品种果实中均含有丰富的营养元素,且含量均是K＞Fe＞Zn＞Ca＞Cu＞Mg＞Mn。不同品种果实中,K,Zn,Mg和Mn含量为美人酥＞红酥脆＞满天红;Fe和Cu含量为红酥脆＞满天红＞美人酥;Ca含量为满天红＞红酥脆＞美人酥;七种营养元素总量为红酥脆＞美人酥＞满天红。