Effects of fresh-cut and storage on glucosinolates profile using broccoli as a case study

Glucosinolates(GLS) contribute to the unique flavour, nutrition, and plant defence of the Cruciferous vegetables. Understanding the GLS changes through postharvest processing is essential for defined preservation. In this study, four different fresh-cut types, whole flower(W),floret(F), quarterly cut floret(QF) and shredded floret(FS) of broccoli, were stored for 0, 1, 2 and 3 day(s) to explore GLS responses to postharvest treatments. As a result, seven GLS were identified, mainly including glucoraphanin(RAA), neoglucobrassicin(NEO), and glucobrassicin(GBC)and accounting for 52.69%, 20.12% and 14.99% of the total GLS(21.92 ± 0.48) μmol · g ^(-1 )DW, respectively. FS had the sharpest decrease in GLS after three days of storage(6.55 ± 0.37) μmol · g-1DW, while QF had the least(10.16 ± 0.33) μmol · g ^(-1 )DW. All GLS components decreased over storage, except for 4-methoxyglucobrassicin(4 ME) in FS and QF, suggesting its key role in serious wound defence. The results suggested certain postharvest approaches influenced the flavour and nutrition of broccoli.

Effect of Magnetic Field Technology on Preservation Quality of Fresh-cut Apple

[Objectives]The paper was to study the effect of magnetic field technology on physicochemical properties of fresh-cut apple during storage.[Methods]Using fresh-cut apples as materials,magnetic field assisted refrigeration and conventional refrigeration control groups were set up,and the preservation effects of magnetic field assisted refrigeration on fresh-cut apples were tested by measuring the changes of microorganisms and physicochemical indicators.In this experiment,the conditions of magnetic field assisted refrigeration group was set as follows:temperature 4℃,magnetic field intensity 5 mT,static magnetic field,and storage for 6 d.[Results]At 6 d post storage,the weight loss rate,total number of colonies and total number of fungi of fresh-cut apples increased;the L value and hardness showed a downward trend;the soluble solid content first increased and then decreased;and the total acid decreased first and then increased.The above indicators in magnetic field assisted refrigeration group changed more gently than that in conventional refrigeration group.Compared with conventional assisted refrigeration,the weight loss rate of fresh-cut apples treated by magnetic field combined with 4℃refrigeration was reduced by 68.00%;the hardness was increased by 12.23%;the total number of colonies and total number of fungi were reduced by 64.15%and 37.50%;and the L value did not change much.High content of soluble solids and total acid was maintained.[Conclusions]Magnetic field assisted refrigeration delays quality deterioration of fresh-cut apples during storage,prolongs shelf life,and further improves their edible quality and commodity value.

Effects of 1-MCP and Chitosan on Active Oxygen Metabolism and Quality of Fresh-cut Potato during Storage

[Objective] The research aimed to study the effects of 1-methylcyclopropene （1-MCP） and chitosan on active oxygen metabolism and quality of fresh-cut potato during storage. [Method] The fresh-cut potato slices were respectively treated with 1- MCP （2 μl/L）, chitosan or 1-MCP ＋ chitosan. During the storage period, the contents of superoxide anion （02）, malondialdehyde （MDA）, hydrogen dioxide （H202） and Vita- min C （Vc）, the activities of polyphenol oxidase （PPO）, peroxydase （POD） and super- oxide dismutase （SOD） as well as the respiratory rate of the fresh-cut potatoes in all the treatments were determined every day. The fresh-cut potato slices treated without any reagents were used as control. [Result] 1-MCP Treated could significantly de- creased the respiratory rate, PPO activity and the accumulations of 02 , H202 and MDA, increased the activities of SOD and POD and slowed down Vc content reduc- tion. On the contrary, potato treated with chitosan significantly inhibited the POD activi- ty in fresh-cut potato. Compared with the control, the combination of 1-MCP and chi- tosan showed a little but not significant better effects on potato preservation. [Conclu- sion] 1-MCP Treated showed the best effects on potato preservation.

小菜蛾抗药性及其生物防治研究进展

小菜蛾作为一种在全球范围内普遍存在的农业害虫,对蔬菜生产构成了严重威胁。目前,针对小菜蛾的防治策略主要包括化学防治、农业防治和生物防治等方法。然而,由于化学农药的大量使用,小菜蛾已经展现出了越来越强的抗药性,这使得其防治变得愈加困难。通过分析国内外的小菜蛾防治技术,可以发现生物防治方法在有效控制小菜蛾的同时,并不会引发害虫的抗药性问题。为了更加清晰地了解小菜蛾造成的危害性,从小菜蛾的发生概况与原因、抗药性的产生及其管理措施、抗药性监测等方面进行了综述。目前,小菜蛾的生物防治主要利用的是真菌、细菌、病毒以及天敌等生物因素。通过对最新研究进展的综述,展望了未来小菜蛾生物防治的发展前景。

不同干燥方式对水芹粉挥发性风味成分影响的研究

该研究采用热风干燥、冷冻干燥和喷雾干燥对鲜水芹进行处理,研究不同干燥方式对水芹粉挥发性风味成分的影响。通过顶空固相微萃取-气相色谱-质谱联用技术对鲜水芹和三种干燥方式下水芹粉的挥发性成分进行分析,结果显示:在鲜水芹、热风干燥水芹粉、冷冻干燥水芹粉和喷雾干燥水芹粉分别鉴定出48、37、47和38种挥发性成分,主要香气成分为萜烯类化合物。

Molecular Phylogeny Determined Using Chloroplast DNA Inferred a New Phylogenetic Relationship of <i>Rorippa aquatica</i>(Eaton) EJ Palmer &Steyermark (Brassicaceae)—Lake Cress

North American lake cress, Rorippa aquatica (Eaton) EJ Palmer & Steyermark (Brassicaceae), is listed as an endangered or threatened species. Lake cress shows heterophyllic changes in leaf form in response to the surrounding environment. Therefore, this species has received considerable attention from ecological and morphological perspectives. However, its phylogenetic position and taxonomic status have long been a subject of debate. To analyze the phylogenetic relationship of lake cress, we investigated chloroplast DNA sequences from 17 plant species. The results of phylogenetic reconstruction performed using trnL intron, trnG (GCC)-trnM (CAU), and psbC-trnS (UGA) indicated that lake cress is a member of Rorippa. Moreover, we found that the chromosome number of lake cress is 2n = 30. This result indicated that lake cress might have originated from aneuploidy of triploid species or via intergeneric crossing. Taken together, our results suggest an affinity between lake cress and Rorippa at the molecular level, indicating that lake cress should be treated as Rorippa aquatica (Eaton) EJ Palmer & Steyermark.

Rheological properties of low fat yogurt containing cress seed gum

Yogurt—a milk based mix fermented by lactic acid bacteria is a valuable health food for both young and old. Milk is the main ingredient of yogurt. However, most yogurts contain additional solids such as milk solids nonfat to boost the nonfat milk solids. Stabilizers such as natural gums are added to improve and maintain gel firmness and consistency, while also for many people to improve appearance and mouth feel. Hydrocolloidsspecifically stabilize gel structure, increaseviscosity and either from networks with milk constituents and establish a separate gel structure. In current research, a natural local plant Iranian hydrocolloid, cress seed gum, is added to yogurt formulation and its rheological propertiesare evaluated using a rotational viscometer. Different famous rheological models have beenused to fit shear stress-shear rate data’s. The results demonstrated that cress seed gum has a good potential to be used as a stabilizer in yogurt formula.

Effect of Storage Conditions on the Sensory Quality, Colour and Texture of Fresh-Cut Minimally Processed Cabbage with the Addition of Ascorbic Acid, Citric Acid and Calcium Chloride

The aim of this study was to investigate the effect of storage conditions on the sensory quality, colour and texture of fresh-cut cabbage during the addition of ascorbic acid, citric acid and calcium chloride. Ascorbic acid maintained the overall quality for 14 days at 0℃ and 7 days at 5℃;no difference, however, was observed regarding browning of cut surface compared to the control sample at both storage temperatures. Calcium chloride maintained the overall quality and cut surface browning for 14 days at both storage temperatures. It was also found that citric acid 1% can be used for minimally processed cabbage. Soaking with citric acid helped retain the color and increased the overall acceptance and organoleptic quality of fresh cut cabbage;it reduced browning of the cut surface and protected against formation of black specks. Citric acid treatment combined with low temperature storage (0℃) prolonged the shelf life of minimally processed cabbage for 22 days, time sufficient for acceptable marketing of the product. The lightness of minimally processed cabbage decreased linearly from 70.94 ± 6 to 63.8 ± 8.5 - 61.3 ± 8 units for the chemical treatments during 22 days of storage at 0℃. Hue angle values during storage time were also significantly influenced by chemical treatments mainly at 0℃.

Effects of Stable Chlorine Dioxide on Sterilization and Preservation of Fresh-cut Narrow-leaf Cattail

At present, chlorine dioxide has been widely used as a bactericide that may become an alternative to chlorine. In this study, fresh-cut narrow-leaf cattail was soaked with 45, 70 and 95 mg/L chlorine dioxide solution, respectively. Fresh-cut narrow-leaf cattail samples were collected regularly to determine changes in surface microbe amount, cellulose content, Vc content, reduction sugar content and sensory quality of narrow-leaf cattail, thus analyzing the effects of chlorine diox- ide on sterilization and preservation of fresh-cut narrow-leaf cattail. The results showed that all three concentrations of chlorine dioxide solution could significantly reduce the amount of microbes on the surface of fresh-cut narrow-leaf cattail and improve the edible safety of products. The initial sterilization efficiency was im- proved gradually as the concentration of chlorine dioxide increased. In addition, chlorine dioxide treatment postponed the increase of cellulose content of fresh-cut narrow-leaf cattail. However, chlorine dioxide oxidized Vc and reducing sugar, and its bleaching effect also exerted a certain impact on the sensory quality of fresh- cut narrow-leaf cattail. Based on comprehensive comparisons, 45 - 70 mg/L chlorine dioxide solution exerted the best effects on sterilization and preservation of fresh-cut narrow-leaf cattail. This study laid the foundation for the production and application of chlorine dioxide solution and promotion of rapid development of nar- row-leaf cattail industry.

Optimization of Preservation on Fresh-cut Yam under Simulated Cold-chain Process

[Objectives]This study was conducted to investigate the effect of compound fresh-keeping liquid on the browning and quality of fresh-cut yam during the cold chain process.[Methods]Under the simulated cold chain condition of 4℃,a uniform design(U6*(64))experiment was carried out to optimize the compound preservative formula,and a better compound preservative formula was obtained using the regression equation.[Results]The compound preservative formula was:AA 0.25%,CA 0.5%,Nisin 0.09%,GSH 0.15%.The compound fresh-keeping liquid effectively delayed the browning of fresh-cut yam and the accumulation of MDA,maintained the content of TSS,inhibited the activity of PAL and delayed the appearance of the maximum activity of POD and POD.[Conclusions]This study provides technical support for the actual extension of the shelf life of fresh-cut yam.

Studies on Genetic Transformation of Fresh-cut Chrysanthemum Using DREB1A Promoted by Stress-induced Promoter rd29A

In this study, DERB1A transcription factor and stress-induced promoter rd29A were isolated respectively and amplified from Arabidopsis thaliana, se- quenced and analyzed by DNAsis. In addition, the stress-induced promoter rd29A was utilized to construct the plant expression vector of DERB1A, which was transformed into Agrobacterium tumefaciens. Furthermore, the transgenic regeneration system of fresh-cut chrysanthemum from callus to plantlets was established successfully. On this basis, chrysanthemum leaf-disc explants were genetically transformed with Agrobacterium-mediated method. Two positive transgenie plantlets were obtained in vitro. Based on PCR detection, DREB1A transcription factor was integrated into chrysanthemum genome, which laid the foundation for breeding new transgenie cultivars of fresh-cut chrysanthemum with high comprehensive stress resistance, good cmalitv and high field.

Effect of Storage Temperature on the Quality of Fresh-cut Cattail

Fresh-cut cattail was extremely not resistant to store at room temperature.In the first day,it began to etiolate and rot,the fiber content increased,but the vitamin C content and reducing sugar content decreased.The aerobic bacterial count increased,the weight loss rate sharply increased,and the sensory quality and food value were gradually lost.Low temperature storage could decrease the loss of vitamin C and reducing sugar of fresh-cut cattail,reduce the weight loss rate and delay the increase of fiber content,maintain the water and nutrient of fresh-cut cattail,and the storage effect of 0 ℃ was better than 4 ℃.

Effects of Lactoperoxidase System Activation-Oregano Essential Oilor Chlorine on the Quality of Modified Atmosphere Packaged Fresh-Cut Iceberg Lettuce

The present work focused on the effects of the Modified Atmosphere Packaging (MAP) 1 (5% O2 and 10% CO2) or 2 (2% O2 and 5% CO2) and the previous addition of Lactoperoxidase System (LPS) and Oregano essential oil or chlorine washing on the quality of fresh-cut lettuce during refrigerated storage at +4?C. Our results showed the significant effect of this combined treatment on quality improvement during storage. Thus, mesophilic bacteria was reduced in treated samples compared to those untreated with number which not exceeded the critical of 5 × 107 UFC?g-1 (p 2 and CO2 levels created by both atmosphere were not significantly different between the two treatments (p > 0.05). Brightness of lettuce samples was significantly reduced during storage. Thereafter, the PCA data showed the effect of combined treatment on the preservation of hygienic, physico-chemical and sensory quality up to the 7th day of refrigerated storage of these treated samples. The results obtained draw attention to modified atmosphere packaging lettuce and the addition of bio-preservatives which could be an alternative of choice to replace chlorine to preserve the sanitary quality of green products.

Influence of cutting size and packaging materials on the quality of fresh-cut winter squash (var. Ajijimang)

Winter squash (var. Ajijimang) washed in 100 mg.L-1 chlorine water and cut into 4 and 8 parts was packed in different packaging materials, 35 μm micro-perforated P-Plus (MPP), 50 μm polyethylene (PE), 80 μm nylon/PE (Ny/PE), and 90 μm PE films separately. Fresh-cut samples were then stored at 10℃ for up to 17 days. The 35 μm MPP having a high oxygen transmission rate (OTR) has the most stable gas exchange ratio while the 80 μm Ny/PE was the most unstable. Firmness of the mesocarp remained acceptable until the end of storage regardless of the cutting size. Soluble solids content (SSC) remained stable and even slightly increased to a certain extent within 6 days. An increase in pH after 10-day storage suggested the activity of microorganisms within the packaging films. Strong off-odor was detected in samples packaged in 80 μm Ny/PE film after 13 days of storage. Mold was observed in all 1/4 cut samples on day 13 except the sample packaged with 80 μm Ny/PE film. However, no mold was found in all 1/8 cut samples except 35 μm MPP film on day 13. Severe mold invasion was apparent on the onset of the 17-day storage in 35 μm MPP film and 50 μm PE film. Samples cut into 8 parts and packed in 80 μm Ny/PE and 90 μm PE films had less mold incidence compared with other two packaging films. Fresh-cut winter squash packaged in 90 μm PE film maintained quality with shelf-life of 10 days at 10℃. Winter squash as fresh-cut commodity, with the right packaging material has the potential for longer period of storage in retail stores.

Effects of 2,5-Norbornadiene （NBD） on Physiological and Biochemical Responses of Fresh-cut Winter Squash

Ethylene is one of the most important plant hormones that regulate physiological responses, maturity and senescence of postharvest fruits and vegetables. The determination of its role in the wound-healing response of fruits and vegetables is helpful in understanding the wound responses. 2,5-Norbornadiene （NBD）, inhibitor ethylene binding were used to determine the effect of ethylene action on wound-induced response of fresh-cut winter squash, a kind of vegetables known to produce ethylene markedly after cutting. The effect of NBD on the physiological and biochemical changes of fresh-cut winter squash was investigated in this experiment. The results showed that NBD had great effects on physio-biochemical metabolism of fresh-cut winter squash. Ethylene production was inhibited significantly by NBD. NBD also had an inhibition effect on polyphenol oxidase （PPO）, peroxidase （POD） and phenylalanine ammonia lyase （PAL） activity. The effect of NBD on lipoxygenase （LOX） activity and superoxide dismutase （SOD） was not obvious. NBD treated sample showed a more rapid increase in catalase （CAT） activity, which may help in healing the damage of the tissue. These information are important in understanding the fundamental biology of wound response and in the development of new technology to hasten wound-healing and, thereby, to minimize costly wound-related problems in fresh-cut industry.

玉米须水芹酒酿造工艺优化

以玉米须与水芹为主要原料,选用酿酒酵母作为发酵菌种,按比例进行混合发酵,考察玉米须水芹酒最佳酿造工艺。以酒精度和感官评分为检测指标,运用单因素试验和Box-Behnken中心组合试验优化发酵条件,对水芹汁与玉米须汁的体积比、菌种添加量、发酵时间以及发酵温度进行控制,得到最佳的发酵工艺条件为水芹汁∶玉米须汁=1∶2(体积比)、菌种添加量0.6%、发酵时间11 d、发酵温度25℃。在该条件下得到的玉米须水芹酒呈淡黄色透明状,酒香醇厚,酒体柔和,且具有一定的抗氧化能力。

野生大雁新发单链环状DNA病毒基因组鉴定和分析

野鸟作为多种致病性病毒的天然宿主,可通过迁徙活动广泛传播病毒,给人类和其他动物的生命安全带来了严峻挑战。本研究中,我们从青海湿地公园的野生大雁泄殖腔拭子中鉴定出13个新型CRESS-DNA病毒全基因组。此外,基于Rep蛋白的系统发育分析表明,这13株新型CRESS-DNA病毒被划分为CRESS-DNA病毒家族的两个不同进化枝,其中1株隶属于未分类的CRESS-DNA病毒簇的分支,而其余12株则全部归类为类双生病毒科(Genomoviridae)。本研究在野生大雁体内发现13个新型CRESS-DNA病毒,将有助于我们对于CRESS-DNA病毒的多样性以及进化起源的研究。

水芹菜叶蔬菜纸成型工艺研究

围绕水芹菜叶蔬菜纸加工中的成型工艺关键点进行研究。实验发现,使用不粘涂料烤盘作为成型载体,并在70℃的鼓风干燥箱中进行干燥,可以使菜纸得到最佳成型效果。复配胶黏剂效果优于单一胶黏剂。在护色打浆后菜泥中添加0.4%羧甲基纤维素钠(CMC-Na)、0.5%海藻酸钠及2%淀粉组成的复合胶黏剂,并且以1%甘油作为增塑剂,可以获得最佳的纸型和风味。

非职业暴露人群血清有机氯农药残留物暴露水平的横断面研究

目的了解我国非职业暴露人群有机氯农药及其残留物的体内暴露水平、相关因素和性别差异。方法于2004年3—7月,运用横断面研究方法,调查了在成都市某综合性医院体检的107名男性和142名女性,均为社区健康人群。运用气相色谱-电子捕获的方法检测其血清中有机氯农药(DDTs和HCHs)水平。运用线性回归分析有机氯农药与年龄和身高体重指数的关系。结果血清中高检出率的有机氯农药及其代谢产物有p,p’-DDE(≥94.4%)、p,p’-DDT(≥91.6%)、β-HCH(≥82.2%)。女性的血清中上述3种物质水平高于男性(经Mann-Whitney检验,P<0.05)。随着年龄增长,这些物质的蓄积量增加(男性:标准偏回归系数≥0.214,P<0.05;女性:标准偏回归系数≥0.321,P<0.05),增长趋势在女性中更为突出。结论有机氯农药及其残留物在本次调查的非职业暴露人群中有一定蓄积,应重点关注有机氯农药蓄积对女性远期健康的影响。

水芹和旱芹营养器官结构和叶片光合特性的比较分析

以水芹品种‘南京八卦洲水芹’和旱芹品种‘六合黄心芹’为材料,采用盆栽的方法,对其营养器官结构和不同光照强度下叶片光合特性进行了比较研究。结果表明:水芹根系维管束比旱芹发达;水芹叶柄为中空结构,有较大的髓腔,而旱芹结构致密,无髓腔;旱芹叶片维管束和韧皮部细胞发达,木质部导管细胞数目较多,而水芹维管束相对不发达,木质部和韧皮部细胞较少。当光照强度为90μmol·m-2·s-1时,旱芹的净光合效率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)分别是水芹的1.45、1.81、1.49和1.69倍;当光照强度为270μmol·m-2·s-1时,旱芹的Pn、Gs、Ci和Tr分别是水芹的1.77、1.61、1.71和1.46倍。在一定光照强度范围内,旱芹和水芹的Pn与Gs、Tr呈正相关,与Ci呈负相关,并且旱芹的Pn要高于水芹。表明2种芹菜的光合特性与叶片的维管束、韧皮部、木质部导管相关。