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.

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.

鲜切荸荠褐变抑制剂组合的筛选

新鲜荸荠经过清洗、挑选、去皮后采用不同抑制剂组合按L9(34)处理,在4℃下贮藏。贮藏期间定期检测鲜切荸荠的褐变度(BD值)、总酚含量(TP)、多酚氧化酶(PPO)和苯丙氨酸转氨酶(PAL)的活性。正交实验结果表明,防褐变的最佳抑制剂组合为0.2%异抗坏血酸(D-AA)+0.05%N-甲酰-L-半胱氨酸(AC)+1.0%的柠檬酸(CA)。与对照(清水)相比,该组合可以较好地抑制鲜切荸荠的褐变,但略差于0.1%亚硫酸氢钠的处理。鲜切荸荠BD值与TP含量、PPO和PAL的活性有显著的相关性。

碱式次氯酸镁对鲜切荸荠护色保鲜效果研究

目的探索碱式次氯酸镁(BMH)对鲜切荸荠的护色效果。方法将鲜切荸荠进行托盘化包装,并在包装中放入BMH小包装袋,通过观测鲜切荸荠的黄化情况来研究BMH对鲜切荸荠的护色效果。结果当BMH小包的质量为4 g时,鲜切荸荠的黄化率较低;控制鲜切荸荠表面的水分也有利于抑制黄化;低温有利于鲜切荸荠的保色,但在高温贮藏条件下可更清楚地看出BMH对鲜切荸荠的护色效果;BMH对鲜切荸荠失重和维生素C变化也有一定的抑制作用。结论 BMH可以用于鲜切荸荠的保鲜。

油莎豆资源的综合开发利用

油莎豆为莎草科多年生草本,全生育期110～130 d,块茎产量高且富含油脂,已成为生产生物柴油的原料植物.油莎豆是多用途的经济作物,除可加工成生物柴油外,还可以进行综合利用.对油莎豆在生物柴油、天然药物、食用油和食品工业等方面的综合开发进行了介绍,以期为油莎豆的综合利用提供借鉴.

鲜切荸荠黄化组织中微生物分离鉴定研究

本研究从鲜切荸荠的黄化表面组织进行分离培养到了5种微生物,包括1种真菌和4种细菌.将分离的5种微生物分别接种到鲜切荸荠表面,结果表明微生物均加快了鲜切荸荠组织黄化的发生.通过形态学研究表明,这5种微生物中真菌为地霉属(Geotrichum)真菌,其余4种细菌分别属于盐水球菌属(Salinococcus)、链球菌属(Strep-tococcus)、黄杆菌属(Flavobacterium)和葡萄球菌属(Staphylococcus)细菌.其中地霉属真菌、链球菌属和葡萄球菌属细菌可导致鲜切荸荠严重黄化.

复合保鲜液对鲜切荸荠的保鲜效果

根据鲜切荸荠在储藏过程中容易氧化变质的现象,研究一种复合保鲜液对鲜切荸荠进行保鲜;利用食盐、白糖、白醋等溶液对鲜切荸荠进行浸泡预处理后再进行包装,置于室温条件(25℃)下储藏;分别测定了特定时间内鲜切荸荠的颜色、硬度、失重率、电导率、多酚氧化酶活性、可溶性固形物、总酚含量等参数,并对气味、胀袋情况等进行了感官评价;同时在单因素试验的基础上进行正交试验。结果表明:最佳工艺组合为食盐浓度80g/L+白糖浓度3g/L+白醋浓度100g/L+浸泡时间15min,与对照组相比,使鲜切荸荠保鲜期延长了6d以上。

油莎豆油制备生物柴油的研究

以油莎豆油为原料,四甲基氢氧化铵为催化剂,通过酯交换反应制备生物柴油。通过单因素试验和正交试验研究了催化剂用量、醇油摩尔比、反应温度和反应时间对生物柴油转化率的影响。结果表明,酯交换反应的最佳反应条件为:催化剂用量为油莎豆油质量的0.5%,醇油摩尔比为6∶1,反应温度50℃,反应时间4.5 h。在最佳反应条件下,生物柴油转化率达94.5%。

青鳞鱼骨粉的食用营养价值及应用研究

研究了青鳞鱼骨粉的食用营养价值及其在玉米粥、马蹄粉和鸡精中的应用。结果表明 :( 1)青鳞鱼骨粉是一种蛋白质含量为 2 7.0 %、脂肪含量为 2 .0 %的典型的高营养低热能食品 ;它具有独特的补钙生物学功能的关键因素和优势。( 2 )青鳞鱼鱼骨粉钙磷比为 2 .3 2∶ 1,钙和铁易于被人体吸收和利用。( 3 )青鳞鱼骨粉氨基酸总量为 2 4 .3 6mg/10 0 g,其中必需氨基酸为 5 .2 3 mg/10 0 g,占氨基酸总量的 2 1.4 9% ;蛋白质质量优越于猪骨粉 ,具有更大的利用价值。 ( 4 )以 10 %的比例将超微鱼骨粉分别添加到策友牌玉米粥 ,互润牌桂花马蹄粉和美极牌鲜鸡精中 ,可以提高产品的感官质量 ,达到强化蛋白质和钙磷铁等矿物质元素。

荸荠产粉废浆中功能组分及其功能效果的初步研究

以马蹄粉厂产粉废浆为原料,提取、分离、纯化了一种功能组分,并对其进行组成成分、化学结构分析以及功能活性测定。实验首先采用溶剂从产粉废浆中粗制功能组分,然后采用层析法对功能组分进行分离纯化,进而用气相色谱和质谱联用测定分析其结构,并采用抑菌谱检测、小鼠体内抗菌试验以及小鼠耳二甲苯致炎法、小鼠跖蛋清致炎法和小鼠醋酸扭体法等方法对其功能活性进行测定。实验结果显示马蹄产粉废浆中的主要功能成分为24-乙基-△7-胆甾醇,该成分有显著的体外和体内抗菌能力,且有明显的消炎作用及对疼痛的抑制作用。

杨桃荸荠复合果汁的工艺研究

以荸荠、杨桃为主要原料,采用正交设计方法筛选了杨桃荸荠复合果汁的最佳配方,确定了荸荠杨桃复合果汁的最佳加工工艺,即:柠檬酸0.1%、苹果酸0.1%、蔗糖10%、荸荠/杨桃30%∶20%;以0.2%CMC-Na为稳定剂;90～95℃下杀菌15min。