Seasonal variations of chemical composition in prickly pear (Opuntia ficus-indica (L.) miller)

The moisture, ash, free reducing sugar, starch, ether extractive, crude protein, amino acid and the heat energy contents of young and mature cladodes of Opuntia ficus-indica, with or without fruits, are described. The measurements were made in each of the following stages of development: vegetative growth (March), full vegetative development, and at the beginning of fructification (October). Independently of developmental stage (different cladode types) the highest values were reached always in young cladodes in the following months: moisture content in March and October; ash and free reducing sugars in March; starch and ether extractive in September and October; crude protein in March and July. Crude fibre was maximal in September and global heat energy in October. The nutritive and caloric value of cladodes are compared to other products used for livestock nutrition.     

枸杞子掺伪检测方法的研究进展

枸杞子以其药用价值和营养品质深受消费者的青睐,广泛应用于食品和保健品行业。但是市场上枸杞子恶意掺杂、掺假现象日益严重,此行为严重影响枸杞子品质、危害消费者健康、损害消费者权益、扰乱市场正常秩序,如何正确鉴别枸杞子真伪成为广大消费者普遍关注的问题。本文对枸杞子的主要掺伪现象进行了综述,并介绍了性状鉴别、显微鉴别、化学成分分析鉴别、分子生物学技术鉴别和基于红外光谱、近红外光谱和拉曼光谱法、机器视觉和电子舌等技术的快速检测方法在枸杞子品种和产地掺伪检测中的应用情况,对不同检测方法的优缺点进行对比分析。通过对枸杞子掺伪主要检测方法的比较,为市场监督枸杞子的品质提供理论基础和研究依据。     

基质固相分散-气相色谱法同时测定蔬菜水果中多种农药残留

建立了一个简单、快速的多种类型农药残留同时分析的新方法。采用一种新的样品前处理方法-基质固相分散(Matrix Solid-Phase Disperse，MSPD)替代传统的液-液萃取、固相萃取，从蔬菜水果中提取、净化三种类型31种常用农药残留(包括11种有机氯、5种拟除虫菊酯、15种有机磷)，用GC-ECD和GC-FPD分析检测，用GC-MS(SIM)进行确证。31种农药的回收率在80．4％～112．7％之间，相对标准偏差小于10％。实验表明本方法适用于各种新鲜蔬菜水果样品的农药残留分析。     

接骨木果油的超临界CO2流体萃取及其微胶囊技术研究

用超临界CO2流体萃取技术对接骨木果油进行萃取,采用四因素三水平正交试验,探讨了萃取压力、温度、时间、CP2流量对接骨木果油萃取率的影响.研究得出最佳萃取条件为:压力30MPa,温度45℃,时间3 h,CO2流量25kg/h.以接骨木果油为心材,食用胶为壁材,经乳化、均质和喷雾干燥得接骨木果油微胶囊,包埋率可达89.6%.     

粥化酶及其在果蔬加工中的应用研究

研究了粥化酶的粗酶特性及其在果蔬加工中的应用，并比较了粥化酶与其它果蔬加工用酶在苹果加工中的应用效果。研究结果表明粥化酶作用的最佳条件符合果蔬加工的要求，它能够不同程度的提高果蔬的出汁率及其澄清度；与其它果蔬加工用酶相比粥化酶具有作用效果好，价格便宜的优点     

青椒果实冷害及诱导抗冷性与氧化胁迫关系的研究

青椒在9℃下冷藏8w，没有出现冷害，膜透性变化不大。而在2℃下贮藏1w后即出现冷害症状，超过4w发生严重冷害，膜透性迅速上升。与9℃贮藏青椒相比，2℃贮藏青椒的SOD活性降低，而CAT活性降低更多；POD活性也低于9℃贮藏青椒，但7w时骤升至峰值。贮前50℃10min或53℃5min热水浸泡处理极显著降低了2℃贮藏青椒的冷害，显著抑制了膜透性的上升。与对照相比，50℃热处理对青椒SOD活性影响不明显而53℃热处理显著提高了3、4和5w时SOD活性。两热处理均极显著提高了青椒CAT活性，对CAT活性的提高超过SOD。两热处理青椒贮藏过程中POD活性呈缓慢下降趋势，避免了对照组青椒POD活性6w时的显著降低和7w时的骤然上升。可见青椒的冷害与低温下活性氧清除酶，特别是CAT活性的降低，导致活性氧化代谢失调有关。而贮前热处理通过提高活性氧清除酶特别是CAT活性，维持活性氧代谢的平衡，抑制膜质过氧化，从而减轻了青椒的冷害。     

Recent developments in cold plasma-based enzyme activity (browning,cell wall degradation,and antioxidant) in fruits and vegetables

According to the Food and Agriculture Organization of United Nations reports, approximately half of the total harvested fruits and vegetables vanish before they reach the end consumer due to their perishable nature. Enzymatic browning is one of the most common problems faced by fruit and vegetable processing. The perishability of fruits and vegetables is contributed by the various browning enzymes (polyphenol oxidase, peroxidase, and phenylalanine ammonia-lyase) and ripening or cell wall degrading enzyme (pectin methyl-esterase). In contrast, antioxidant enzymes (superoxide dismutase and catalase) assist in reversing the damage caused by reactive oxygen species or free radicals. The cold plasma technique has emerged as a novel, economic, and environmentally friendly approach that reduces the expression of ripening and browning enzymes while increasing the activity of antioxidant enzymes; microorganisms are significantly inhibited, therefore improving the shelf life of fruits and vegetables. This review narrates the mechanism and principle involved in the use of cold plasma technique as a nonthermal agent and its application in impeding the activity of browning and ripening enzymes and increasing the expression of antioxidant enzymes for improving the shelf life and quality of fresh fruits and vegetables and preventing spoilage and pathogenic germs from growing. An overview of hurdles and sustainability advantages of cold plasma technology is presented.     

Internal Modified Atmospheres of Coated Fresh Fruits and Vegetables: Understanding Relative Humidity Effects

ABSTRACT: Internal atmosphere modification in fruits and vegetables by surface film coatings depends on film permeability, coating thickness, and fruit surface coverage. Research in this area has been mostly empirical, with unpredictable results and diverse conclusions. To reduce variability, it is necessary to have a better understanding of factors that may influence the response of coatings applied to fruits. One factor is relative humidity (RH), which is known to affect the permeability of biopolymer films. By using steady-state mathematical models as tools, we hypothesize that fruits coated with hydrophilic films will be largely influenced by the RH of storage conditions. For hydrophobic materials, RH would have less influence on coating performance.     

Novel Trends to Revolutionize Preservation and Packaging of Fruits/Fruit Products: Microbiological and Nanotechnological Perspectives

Fruit preservation and packaging have been practiced since ages to maintain the constant supply of seasonal fruits over lengthened periods round the year. However, health and safety issues have attracted attention in recent decades. The safety and quality assurance of packaged fruits/fruit products are vital concerns in present day world-wide–integrated food supply chains. The growing demand of minimally or unprocessed packaged fruits has further aggravated the safety concerns which fuelled in extensive research with objectives to develop novel techniques of food processing, preservation, and packaging as well as for rapid, accurate, and early detection of contaminant products/microbes. Nevertheless, fruits and fruit-based products have yet to observe a panoramic introduction. Tropics and subtropics are the stellar producers of a variety of fruits; majority if not all is perishable and prone to postharvest decay. This evoked the opportunity to critically review the global scenario of emerging and novel techniques for fruit preservation and packaging, hence providing insight for their future implementation. This review would survey key nanotechnology innovations applied in preservation, packaging, safety, and storage of fruits and fruit-based products. The challenges and pros and cons of wider application of these innovative techniques, their commercial potential, and consumer acceptability have also been discussed.