Allium cepa chromosome aberration and micronucleus tests applied to study genotoxicity of extracts from pesticide-treated vegetables and grapes

The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. The test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of A. cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. This study evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in A. cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.     

Pesticide residues in leafy vegetables,stalk and stem vegetables from South Korea: a long-term study on safety and health risk assessment

South Korea has a unique food culture. South Koreans enjoy wrapping meat and eating or making kimchi (traditionally fermented Korean food) and eating using raw leafy vegetables, stalk and stem vegetables. Therefore, there is a high chance of being exposed to pesticide residues of vegetables. The objective of this study was to investigate pesticide residues in leafy vegetables, stalk and stem vegetables from South Korea. A total of 8496 samples were mainly collected from Gwangju and Jeonnam area (the largest production region of leafy vegetables, stalk and stem vegetables) in South Korea from 2010 to 2014. A total of 230 pesticides were used for multi-residue analysis of pesticides. Among 8496 samples, 61 different pesticides (1029 times) were detected in 890 samples, of which 118 samples (1.4%) exceeded the Korea maximum residue limits (MRLs). Samples exceeding the MRLs were mostly found in leafy vegetables (brassica lee ssp. namai, leafy lettuce, spinach, perilla leaves, crown daisy, marsh mallow, aster scaber, pimpinella brachycarpa) and Chinese chive. Procymidone, dimethomorph and azoxystrobin were the most frequently found pesticides. A risk assessment of pesticides exceeding the MRLs was evaluated by calculating the estimated daily intake (EDI) and the acceptable daily intake (ADI). The ratio of EDI to ADI was 0.003–30.4%.     

Antioxidant and micronutrient quality of fruit and root vegetables from the Indian subcontinent and their comparative performance with green leafy vegetables and fruits

Commonly consumed, fruit vegetables (12) and root vegetables (15) in the Indian subcontinent in cooked and uncooked states assessed for inhibition of thiobarbituric acid reactive substances (TBARS), superoxide radical scavenging activity (SOSA), ferrous iron chelating ability (FICA) and nine micronutrients, exhibited large variability in these parameters. SOSA and FICA were significantly associated (r = 0.803, p < 0.001) with each other. Inhibition of TBARS showed marginal correlation with both FICA (0.38, p < 0.05) and SOSA (0.29, p > 0.05). There were significant cooking losses for each of the assessed antioxidant capacity parameters (p < 0.05). Contents of ascorbic acid, per 100 g of cooked fruit and root vegetables were high (61.9 and 31.3% of recommended daily allowance (RDA)). However, both the food classes were not good sources of beta‐carotene, riboflavin and thiamine (1.66–5.26% RDA). When compared with our data on 30 cooked green leafy vegetables (GLV) and 30 fresh fruits, root vegetables showed significantly (p < 0.05) higher levels of zinc and selenium. Cooked root vegetables were comparable with cooked GLVs but uncooked GLVs gave the highest values for inhibition of TBARS (0.73 ± 0.21 mM vitamin E/100g). SOSA (40.7 ± 15.6 mM tannic acid/100g) and FICA (41.6 ± 14.9 mM EDTA/100g) were highest for uncooked fruit vegetables. Root vegetables had the highest levels of polyphenols (251.4 ± 107.3 mg/100g). For the present study, popular fruits and vegetables such as guava, spinach, bitter gourd (Momordica charantia), yam, ginger and beetroot, and also less common ones like bael (Aegle marmelos), kokum (Garcinia indica) and mango‐ginger (Curcuma ameda), showed potential in vitro to combat oxidative stress. Copyright © 2005 Society of Chemical Industry     

微波干燥技术在果蔬干制中的应用

系统地介绍了果蔬干制的工艺流程、操作方法及在加工过程中的注意事项。以一些具体的果蔬为例,介绍了微波干燥在果蔬干制中的具体应用,通过与其他干制方法进行对比,来比较微波干燥在果蔬加工方面的优劣性,并在此基础上对今后微波干制技术做了预测,提出了一些建议。     

Chitosan: antimicrobial activity, interactions with food components and applicability as a coating on fruit and vegetables

Chitosan has recently gained more interest due to its applications in food and pharmaceutics. Among others, the antimicrobial activity of chitosan has been pointed out as one of its most interesting properties of chitosan.The aim of this study was threefold: (1) the quantification of the antimicrobial effect of chitosan with a deacetylation degree of 94% and a molecular weight of 43 kDa on different psychrotrophic spoilage organisms and food pathogens. (2) The determination of the influence of different food components (starch, whey protein, NaCl and oil) on the antimicrobial effect of chitosan and (3) the investigation of the effects of chitosan coatings on controlling decay of minimally processed fruits and vegetables (strawberry and lettuce). For the first aim several bacteria and yeast were exposed to chitosan concentrations varying from 40 to 750 mg/l. Generally, Gram-negative bacteria seemed to be very sensitive for the applied chitosan (MIC0.006% (w/v)) while the sensitivity of Gram-positive bacteria was highly variable and that of yeast was intermediary (0.01% (w/v)). To achieve the second aim, the media, with one of these components added, were inoculated with Candida lambica (±2 log cfu/ml) and were incubated at 7°C until the yeast reached the stationary phase. Starch, whey proteins and NaCl had a negative effect on the antimicrobial activity. Oil conversely had no influence. For the third aim, the chitosan coating was formed by dipping the products in a chitosan–lactic acid/Na-lactate solution from which the pH was adjusted to the pH of the products. These products were equilibrium modified atmosphere (EMA)-packaged, stored at 7°C and during storage sensorially and microbiologically evaluated. A chitosan coating on strawberries was applicable while on mixed lettuce the chitosan coating was not applicable due to the development of a bitter taste. The microbiological load on the chitosan-dipped samples was lower for both products. The antimicrobial effect of chitosan on lettuce disappeared after 4 days of storage, while it maintained on the strawberries during 12 days.     

Anti-inflammatory effects of phytochemicals from fruits,vegetables, and food legumes: A review

Inflammation is the first biological response of the immune system to infection, injury or irritation. Evidence suggests that the anti-inflammatory effect is mediated through the regulation of various inflammatory cytokines, such as nitric oxide, interleukins, tumor necrosis factor alpha-α, interferon gamma-γ as well as noncytokine mediator, prostaglandin E₂. Fruits, vegetables, and food legumes contain high levels of phytochemicals that show anti-inflammatory effect, but their mechanisms of actions have not been completely identified. The aim of this paper was to summarize the recent investigations and findings regarding in vitro and animal model studies on the anti-inflammatory effects of fruits, vegetables, and food legumes. Specific cytokines released for specific type of physiological event might shed some light on the specific use of each source of phytochemicals that can benefit to counter the inflammatory response. As natural modulators of proinflammatory gene expressions, phytochemical from fruits, vegetables, and food legumes could be incorporated into novel bioactive anti-inflammatory formulations of various nutraceuticals and pharmaceuticals. Finally, these phytochemicals are discussed as the natural promotion strategy for the improvement of human health status. The phenolics and triterpenoids in fruits and vegetables showed higher anti-inflammatory activity than other compounds. In food legumes, lectins and peptides had anti-inflammatory activity in most cases. However, there are lack of human study data on the anti-inflammatory activity of phytochemicals from fruits, vegetables, and food legumes.     

Lutein: a valuable ingredient of fruit and vegetables

Lutein is a human serum carotenoid which is not synthesized by humans and thus must be obtained by the ingestion of food containing it such as fruits and vegetables. Lutein is present in different forms in those foods as all-trans-lutein, cis-lutein, epoxi-lutein, and lutein linked to proteins. It discusses if the intake of lutein or diets supplemented with lutein or diets rich in fruits and vegetables are important in the prevention of diseases like some cancers, cardiovascular diseases, etc., that may be affected by the antioxidant effect of lutein; or in the prevention of age-related macular degeneration and other eye diseases. The concentration of lutein in fruits and vegetables depends on the species. We've included the concentration of lutein in 74 species reported by different authors since 1990. Currently the quantification of lutein is mainly performed by HPLC, but more investigations into a quantification method for lutein, lutein isomers, and epoxi-lutein are necessary. Improvement of lutein extraction methods is important as well. Methods commonly used in the vegetable and fruit industry like heat treatment, storage conditions, etc. can change lutein concentrations; other factors depend on the plant, for instance the variety, the stage of maturity, etc.     

Nitrate-N determination in leafy vegetables: Study of the effects of cooking and freezing

Nitrate upon reduction to nitrite can cause methaemoglobinaemia or act as precursor in the endogenous formation of carcinogenic nitrosamines. The leafy vegetables are the major vehicle for the entry of nitrate into the human system. The present study was conducted to establish a flow injection analysis (FIA) technique to investigate the nitrate-N contents of four commonly consumed fresh leafy vegetables (Chinese cabbage, celery, lettuce and English cabbage) from market in Fiji. Two extraction techniques (activated carbon and alkaline extraction) were assessed to extract nitrate-N and the activated carbon extraction was preferred over alkaline extraction and applied. The recoveries of spiked nitrate-N in vegetable matrices ranged from 90.40% to 112.80% in activated carbon extraction with an average of 100.62%. The effects of cooking (boiling, baking and frying) and deep-freezing on the nitrate-N contents were also studied. Nitrate contents in selected leafy vegetables were determined by FIA coupled with Greiss protocol involving sulfanilamide and N-(1-naphthyl)ethylenediamine dihydrochloride as color reagents. Nitrate was determined in the linear range from 1.0 to 20.0 mg L⁻¹ with the method detection limit of 0.042 mg L⁻¹ (0.34 mg kg⁻¹). The results of the study show that nitrate contents in fresh leafy vegetables ranged from 1297 to 5658 mg kg⁻¹. Boiling reduces nitrate content by 47–56% whereas frying in Soya bean oil elevates nitrate content by as much as 159–307%. No significant change was observed in nitrate content after baking. The deep-freezing of the selected leafy vegetables shows that nitrate-N content fluctuates slightly from the original nitrate-N values over the seven day period. The FIA throughput was 38 samples h⁻¹.     

茉莉酸甲酯在采后果蔬品质控制中的应用

茉莉酸甲酯(Me JA)是环戊酮衍生物之一,茉莉酸甲酯作为植物体内一类信号物质,在植物的生长发育、应激反应和次生代谢过程中发挥类似激素的作用,对植物的生长发育和防御系统都具有一定影响。本论文通过对茉莉酸甲酯对采后果蔬品质控制中的应用进行综述。茉莉酸甲酯(Me JA)通过诱导果蔬产生并提高细胞壁水解酶(如几丁质酶、β-1,3-葡聚糖酶)和抗性物质合成酶(如苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶)的活性,从而增强果蔬对机械损伤和病原侵染的抗性。同时,茉莉酸甲酯还能能够诱导植物防御基因的表达,诱导果蔬产生一系列具有防御功能的次生代谢物质(如花青素等)来改善果蔬保鲜品质。     

鲜切果蔬酶促褐变发生机理的研究

为了进一步揭示鲜切果蔬酶促褐变发生过程及其机理,采用鲜切茄子和鲜切甘薯为实验材料,研究了与酶促褐变发生密切相关的酶活性变化及伤害胁迫生理。结果表明:两种果蔬经鲜切处理后诱发了酶促褐变的快速发生,鲜切甘薯的酶促褐变反应滞后于鲜切茄子。在贮藏期间两种果蔬的过氧化物酶(POD)活性和丙二醛(MDA)含量逐渐上升,总酚含量与苯丙氨酸解氨酶(PAL)活性变化一致,均先升后降。鲜切甘薯多酚氧化酶(PPO)活性逐渐上升,但鲜切茄子的PPO却呈下降趋势。结果还表明:鲜切果蔬不仅在切割表面发生酶促褐变反应,在远离切割部位也诱发了生理生化反应,这可能是由于切割伤害胁迫产生的刺激信号转导而引致组织的整体协同伤害防御反应的结果。     

果蔬烫漂护色技术应用研究进展

烫漂护色是果蔬在干燥、油炸、冷冻及储存等加工处理前的一个重要的操作单元。烫漂的主要目的是钝化果蔬中引起不良变化反应的氧化酶,防止色泽劣变。烫漂方法主要包括化学法和物理法。化学试剂的残留对人的身体健康存在一定的威胁。传统的烫漂技术(热水及蒸汽烫漂)存在传热速度慢、营养损失大、水消耗量巨大、污水处理困难等缺点。因此,急需开展新的烫漂技术的研究。本研究对各种新型烫漂技术的原理、研究进展、应用现状和局限性等进行了分析和综述,主要包括微波、红外线、欧姆加热、射频、超高压等,以期为果蔬烫漂护色技术研究方向提供启示。     

生物保鲜剂在果蔬保鲜中的应用研究进展

生物保鲜剂具有天然、无毒等特点,越来越受到人们的青睐,在果蔬保鲜中有着广阔应用前景。本研究概述了生物保鲜剂的定义与保鲜机理,然后从植物类、动物类、微生物类和酶类这4个方面详细阐述生物保鲜剂用于果蔬保鲜的国内外研究现状,分析了生物保鲜剂在果蔬保鲜发展中存在的问题,并对其应用前景进行展望,旨在为生物保鲜剂在果蔬保鲜应用的深入研究提供参考。     

果蔬燕麦食品营养与开发利用进展

燕麦片是一种营养丰富、方便快捷、易于携带的食品。燕麦食品能基本满足人体所需能量,但维生素和矿物质等成分相对不足,不能满足机体一餐的全部营养需求。果蔬是人体获取维生素、矿物质和膳食纤维的主要来源,与人体健康密切相关,早餐合理摄取一定量的果蔬是身体健康的重要保证。果蔬燕麦食品的开发,能更好地满足人体对营养的需要,为人们提供了更好的早餐选择。本文综述了燕麦的营养保健功能、果蔬燕麦片的开发优势,并对其未来发展趋势进行了阐述,以供果蔬燕麦食品的研究和开发提供参考。     

传统发酵蔬菜中拮抗温和气单胞菌的乳酸菌的筛选与鉴定

目的:从传统发酵蔬菜中筛选对温和气单胞菌具有拮抗作用的乳酸菌。方法:采用双层琼脂扩散法筛选,通过生理生化反应和16S rRNA序列分析进行鉴定,研究蛋白酶、p H和温度等因素对乳酸菌无细胞上清液（CFS）抑菌活性的影响,采用扫描电镜分析乳酸菌无细胞上清液对温和气单胞菌细胞结构完整性的影响。结果:从腌渍酸黄瓜中筛选出对温和气单胞菌（10⁶CFU/m L）具有较强抑制活性的菌株LZH2-5,经鉴定为植物乳杆菌（Lactobacillus plantarum）。LZH2-5无细胞上清液经胰蛋白酶、木瓜蛋白酶、中性蛋白酶、碱性蛋白酶和胃蛋白酶处理后其抑菌活性分别丧失29.38%、23.93%、22.30%、19.47%和14.59%;经40、60、80℃处理30 min后其拮抗活性基本不变,在100℃和121℃处理30 min后活性分别下降了16.66%和25.40%,在p H3.0⁴.0范围内保持其抑菌活性,粗提物的最小抑菌浓度12.0 mg/m L。扫描电镜表明经LZH2-5 CFS处理使温和气单胞菌的细胞结构破坏并溶解。结论:从腌渍酸黄瓜中筛选的植物乳杆菌LZH2-5对温和气单胞菌具有较强抑制作用,初步分析抑菌活性物质为细菌素类,可作为水产品养殖过程中控制温和气单胞菌的拮抗制剂出发菌株。      

复合果蔬肉制品研究与应用进展

为促进肉制品生产的多样性并同时拓展果蔬的应用领域,使得肉制品营养、保健、色泽诱人且口味独特,在肉制品的加工中添加果蔬形成复合果蔬肉制品,已经成为肉制品发展的一个新方向,开发及应用前景广阔。果蔬的添加形式与添加量、工艺路线等因产品形式不同而异。本文综述了近年来复合果蔬肉制品的研究进展情况,包括原料研究、新产品的开发、关键技术研究、研究与应用存在的一些主要问题及应对策略,以期为肉类深加工、果蔬的充分利用及高档复合肉制品的开发提供借鉴参考。      

果蔬加工副产物的利用现状及发展趋势研究进展

我国果蔬加工业发展迅速,果蔬加工副产物也随之增多,由此而引发的废弃物污染越来越严重。同时,果蔬加工副产物含有的多种有效成分,没有加以利用而造成的资源损失也不可忽视。本文阐述了果蔬加工副产物的利用现状,分析了果蔬加工副产物的发展趋势,并就果蔬加工副产物的综合利用提出建议。      

果蔬中菊酯类农药-氯氰菊酯检测技术的研究进展

氯氰菊酯是一种拟除虫菊酯杀虫剂,因杀虫能力强和药效持久等特点被广泛应用于果蔬农产品的害虫防治。但由于长期广泛使用,会残留于食品和环境中,从而对环境和人体健康造成危害。本文主要介绍了近些年使用较多的仪器检测方法以及主要的快速检测方法的研究现状,以期为菊酯类农药-氯氰菊酯检测技术的进一步发展提供参考。     

鲜切果蔬天然抗菌剂的研究进展

鲜切果蔬因其新鲜营养、方便即食的优点,而拥有广阔的市场前景。由微生物引起的腐败变质及食源性疾病是影响鲜切果蔬质量与安全的重要因素,控制鲜切果蔬的微生物污染能够促进鲜切果蔬加工业健康稳定的发展。天然抗菌剂具有高效、无毒、环保等优点,采用天然抗菌剂控制鲜切果蔬的微生物污染能够减少化学合成类抗菌剂对人体健康产生的不良影响,避免食品加工过程中带来的潜在危害。概述了植物、动物和微生物来源的天然抗菌剂在鲜切果蔬微生物控制中的研究进展,并对鲜切果蔬天然抗菌剂的发展前景进行了分析。