不同石榴品种果实成熟期酚类物质组分与含量分析

【目的】为了揭示不同石榴品种成熟期果实酚类物质组分与含量的差异,【方法】以‘水晶甜’、‘红宝石’和‘绿宝石’3个不同果色表现型(白皮、红皮、绿皮)石榴品种为试材,利用高效液相色谱法(HPLC)分别测定其果皮、种子和果汁中酚类物质的组分与含量。【结果】各石榴品种果皮和种子中共检测到13种酚类物质,果汁中检测到12种,未检测到表儿茶素。不同品种同一部位酚类物质含量差异显著,在果皮、种子和果汁中‘绿宝石’石榴多酚含量最高,‘水晶甜’果皮和果汁中多酚含量最低,‘红宝石’种子中多酚含量最低。各石榴品种不同部位多酚的总量均是果皮(5.957 mg·g-1)最高,主要成分为对羟基苯甲酸、表儿茶素和儿茶素;果汁(1.037 mg·g-1)次之,主要成分为儿茶素和对羟基苯甲酸;种子(0.295 mg·g-1)含量最低,主要成分为根皮苷和儿茶素。【结论】石榴不同品种不同部位酚类物质含量存在显著差异。     

‘突尼斯软籽’石榴防寒栽培技术

‘突尼斯软籽’石榴籽软味甜、综合性状优良,但抗寒性差易遭受冻害。综述了‘突尼斯软籽’石榴栽培中的防寒栽培技术,以期为‘突尼斯软籽’石榴的防寒栽培提供借鉴指导。     

Predictions of viscoelastic behavior of pomegranate using artificial neural network and Maxwell model

Stress relaxation is one of the defined tests to characterize the viscoelastic properties of food and agricultural materials. Stress relaxation data are very important because they provide useful and valuable information such as fruit firmness and ripening, food processing and predicting changes in the material during mechanical loading. Viscoelastic behavior of some varieties of pomegranate that are cultivated in Iran has been studied in current research. For this purpose, stress relaxation test was conducted with three cultivars of pomegranate (Ardestani, Shishekap and Malas) for three sizes (small, medium and large). In this article the potential of artificial neural network (ANN) technique is evaluated as an alternative method for Maxwell model to predict the viscoelastic behavior of pomegranate. Neural stress relaxation models were constructed to describe stress relaxation behavior of pomegranate with respect to time. The neural models were built based upon relaxation time as input network and stress relaxation as output network. The results revealed that both ANN model and Maxwell model have high capability of producing accurate and reliable predictions for stress.     

Study of pomegranate ripening by dielectric spectroscopy

Pomegranate (Punica granatum L.) is one of the fruits most recently studied for its many health benefits and its high antioxidant capacity and total phenolic content. Currently, the industry uses destructive methods to ensure the quality standards demanded by consumers. In this context, dielectric spectroscopy is presented as an interesting technique to monitor, on-line, fruit quality standards and ripening changes. The aim of this study is to analyze the effect of the major components of pomegranate and its structure on the dielectric spectrum between 500 MHz and 20 GHz. Some physical, chemical and dielectric measurements were carried out in the arils, spongy white tissues and peel. A maturity index was defined based on dielectric properties of fruit at two different frequencies, 2.4 and 1.2 GHz. The results demonstrated the utility of this index for pomegranate.     

XopN-T3SS effector modulates in planta growth of Xanthomonas axonopodis pv. punicae and cell-wall-associated immune response to induce bacterial blight in pomegranate

Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Xap) is an important disease of pomegranate. Most phytopathogenic strains in the Genera Xanthomonas secrete effector proteins by the type III secretion system (T3SS) to suppress pathogen-associated molecular pattern (PAMP)-triggered plant immunity (PTI). The T3SS effectors, referred to as Xanthomonas outer proteins (Xops), are known to be key factors required for bacterial growth and colonization in distinct eukaryotic hosts. Xap contains six Xop-effectors, namely XopC2, XopE1, XopL, XopN, XopQ and XopZ. In this study we analyzed xopN, a conserved effector in Xanthomonas, with reference to sequence identity and its role in governing bacterial growth, and virulence. The xopN of Xap shared maximum sequence identity (98.6%) with pathovar citri. Overlapping extension PCR and double crossing over based homologous recombination strategy was employed to generate a xopN null mutant (Xap ΔxopN) of Xap. A kanamycin gene was used to replace the xopN gene. XopN was required for maximal Xap pathogenicity in its natural host pomegranate. The detailed image analysis on blight lesions revealed 3 fold reduction in watersoaked areas on leaves infiltrated with mutant Xap ΔxopN compared to that of with wild Xap. The in planta population count of Xap ΔxopN was reduced approximately 32-fold relative to the wild strain indicating that xopN is required for maximal growth of Xap in pomegranate. In addition, the Xap ΔxopN mutant induced more callose deposition in infected pomegranate leaves. Taken together, the present study shows that XopN governs Xap growth and modulates cell-wall associated immune response in pomegranate.     

Putrescine and carnauba wax pretreatments alleviate chilling injury,enhance shelf life and preserve pomegranate fruit quality during cold storage

Keeping in mind to reduce chilling injury and retain quality; pomegranate (Punica granatum L., cv. Mridula) fruits were treated with putrescine, carnauba wax and putrescine + carnauba wax prior to cold storage at 2 °C. Before analyzing physical, physiological and biochemical parameters fruits were subjected to post cold storage exposure at 20 °C for 3 days. Untreated fruits developed rapidly chilling injury, with main symptoms being brown discolouration of the skin, surface pitting, weight and firmness loss during storage. All these undesirable changes were significantly delayed by putrescine + carnauba wax application. Respiration and ethylene evolution rate were also brought down by combined application of putrescine and carnauba wax treatment. The superiority of combine treatment over other applications seems arises due to additive benefit of antisenescence and barrier properties of putrescine and carnauba wax, respectively.     

响应面法优化超声波辅助提取石榴皮多糖的工艺

本研究采用超声波辅助提取石榴皮多糖,响应面法优化了超声波辅助提取石榴皮多糖的最佳工艺条件。Box-Behnken设计用于评估四个独立变量(液料比,提取时间,提取温度,超声功率)对石榴皮多糖产量的影响。研究表明,液料比为23 mL/g,提取时间62 min,提取温度57℃,超声功率为145 W,是石榴皮多糖的最佳提取条件。在最适条件下,石榴皮多糖产量为(13.64±0.21)%,预测收益率为13.81%。     

石榴花挥发油的GC-MS分析及β-葡萄糖苷酶对石榴花的增香作用研究

目的:研究石榴花挥发油的化学成分及β-葡萄糖苷酶对其的增香作用。方法:使用挥发油提取器提取石榴花的挥发油,以GC-MS法进行分析鉴定,用面积归一化法获得各化合物的相对含量。结果:分别从无酶和有酶的石榴花挥发油提取物中确证了42个化合物。证明β-葡萄糖苷酶可以增加石榴花中某些香精成分的相对含量,但也使其中某些成分的相对含量减少。结论:石榴花中的化学成分十分丰富,GC-MS可以对石榴花挥发油进行良好的分离鉴定,同时证明β-葡萄糖苷酶对石榴花的增香作用不显著。     

论我国石榴现代生产基地的规划建设

石榴是一种栽培历史悠久的世界性水果,随着对其医疗保健价值的不断认识,石榴的消费量、产量和面积在逐年增加。文章论述了当前我国石榴商品化生产基地规划和关键生产技术,对促进我国石榴产业发展具有重要意义。