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.

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.

Fresh-keeping Effects of Different Concentrations of 6-BA and B9 on Carnation Cut Flower

Using sucrose, citric acid and vitamin C as the basic liquid, different concentrations of 6-BA and B9 preservatives were added, and the carnation variety ＇ Master＇ was treated. The results showed that the formula of 3% sucrose ＋ 50 mg/L citric acid ＋ 600 mg/L vitamin C ＋ 20 mg/L 6-BA could effectively maintain the water balance of the cut flower, prolong the vase life of the cut flower to 16.4 d, and maximize the flower diameter and the crown height.

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.

弱酸性电解水用于提升鲜切马铃薯安全品质的研究

目的探究弱酸性电解水和自来水处理的鲜切马铃薯在室温贮藏条件下不同时间段内品质的变化。方法模拟现代厨房贮存模式,经弱酸性电解水和自来水处理的鲜切马铃薯在室温(25±0.5)℃贮藏环境下,贮藏0、7、14、21、28、35h时,检测其感官、色度、质构、淀粉、蛋白质、钾、维生素C、菌落总数、大肠杆菌、沙门氏菌、金黄色葡萄球菌、霉菌、酵母菌。结果经弱酸性电解水处理的鲜切马铃薯在室温贮藏21 h内,经自来水处理的鲜切马铃薯在室温贮藏14 h内,感官正常,其营养成分淀粉、蛋白质、维生素C、钾元素下降较少,金黄色葡萄球菌、沙门氏菌、菌落总数、大肠杆菌、霉菌、酵母菌的含量均在国家标准和团体标准许可的安全范围内,可安全食用。结论弱酸性电解水可显著提升鲜切马铃薯的贮藏品质,抑制其金黄色葡萄球菌、沙门氏菌、菌落总数、大肠杆菌、霉菌、酵母菌繁殖,延长室温贮藏期。

UTILIZATION AND FRESH PRESERVATION OF CUT LEAVES OF FIVE WILD PTERIDOPHYTE SPECIES ON MAOER MOUNTAINS

The cut leaves of five pteridophyte species were evaluated on their usage in cut flowers. Two species, Lunathy rium coreanum and Dryopteris crassirhizoma, were selected. The ef fects of vase-holding and fresh preservation of the cut leaves under different conditions was studied. By measuring the contents of soluble protein and chlorophyll of leaves, the best methods of fresh preservation was determined with the use of fresh preservation and wet storage. L. rium coreanum (christ) Ching may last 14 days. The best liquid used to arrange flowers in a vase is 5 g/L sucrose.With the use of fresh preservation liquid and wet storage. D. crassirhizoma may last 34 days.

褪黑素对鲜切山药酶促褐变的作用效果

分别采用1、2、3 mmol/L的褪黑素溶液处理鲜切铁棍山药,以蒸馏水浸泡鲜切山药为对照,室温(25℃)下存放4 d,测定鲜切山药颜色参数(L^(*)、a^(*)、b^(*)、总色差值(ΔE))、多酚氧化酶(PPO)活性、过氧化物酶(POD)活性、苯丙氨酸解氨酶(PAL)活性、过氧化氢酶(CAT)活性、H2O2含量、脂氧合酶(LOX)活性、丙二醛(MDA)含量、DPPH自由基清除率和ABTS自由基清除率等指标,探究褪黑素对鲜切山药酶促褐变的作用效果。结果表明:褪黑素处理能抑制鲜切山药中PPO、POD、PAL和LOX活性,贮藏4 d时,3 mmol/L褪黑素处理的样品的PPO、POD、PAL和LOX活性比空白对照组的分别小51.6%、65.6%、27.1%、24.6%;褪黑素处理能降低山药中H2O2和MDA含量,贮藏4 d时,3 mmol/L褪黑素处理的样品的H2O2和MDA含量相比空白对照组的分别降低了84.8%和21.0%;褪黑素处理能提高山药中CAT活性,贮藏4 d时,3 mmol/L褪黑素处理的样品的CAT活性为空白对照组的1.96倍;褪黑素处理能提高山药的DPPH和ABTS自由基清除能力,贮藏4 d时,3 mmol/L褪黑素处理样品DPPH和ABTS自由基清除率比空白对照组的分别提高了20.6%、18.7%;褪黑素处理也能有效延缓鲜切山药表面褐变,且其效果具有浓度依赖性,3 mmol/L的褪黑素护色效果最好,贮藏4 d时,3 mmol/L褪黑素处理的样品的L^(*)值比空白对照组大32.5%,a^(*)、b^(*)、ΔE比空白对照组分别小74.0%、50.7%、67.3%;相关分析结果显示,鲜切山药的ΔE与L^(*)、a^(*)、b^(*)、PPO活性、POD活性、PAL活性、H2O2含量和MDA含量均呈极显著相关,与ABTS自由基清除率呈显著相关。

UV-C照射对鲜切豇豆的保鲜效果研究

为探究短波紫外线(UV-C)照射对鲜切豇豆的保鲜效果,在预试验结果的基础上,分别采用0、0.5 kJ/m^(2)的UV-C处理豇豆,然后将其置于4℃条件下贮藏,定期测定相关指标。结果表明:采用0.5 kJ/m^(2)UV-C照射可以维持鲜切豇豆较高的VC、可溶性固形物、可溶性蛋白和叶绿素含量,减少鲜切豇豆丙二醛(MDA)的积累,同时还能保持鲜切豇豆较高的总酚、类黄酮含量,并提高抗氧化酶的活性,包括过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX),一定程度上稳定多酚氧化酶(PPO)的活性。综合来说,0.5 kJ/m^(2)UV-C处理可用于鲜切豇豆的贮藏保鲜。

1-MCP协同活性炭处理抑制鲜切胡萝卜木质化形成研究

鲜切胡萝卜在贮藏过程易发生木质化,导致品质下降。为探究1-MCP协同活性炭处理对鲜切胡萝卜木质化抑制保鲜效果,文章分析了乙烯利、活性炭、1-MCP和1-MCP协同活性炭等4种处理方式对鲜切胡萝卜硬度、总酚、抗氧化性、PPO、POD、PAL和木质素含量的影响。结果表明:1-MCP协同活性炭处理显著延缓了胡萝卜硬度下降;在贮藏第10 d总酚含量达0.20 mg GAE·g^(−1),显著高于其他处理组(P<0.05);抗氧化性也保持最高水平;DPPH自由基清除活性为0.90μmol TE·g^(−1);PPO、POD活性分别为0.23 U·g^(−1)和61.08 U·g^(−1),显著低于对照组(P<0.05);PAL活性和木质素含量分别为81.67 U·g^(−1)和65.88 mg·g^(−1),也显著低于对照组(P<0.05)。可见,1-MCP协同活性炭处理可有效抑制鲜切胡萝卜木质化,提升其贮藏品质。

不同质量分数柠檬酸和维C对鲜切糯米山药的保鲜效果研究

糯米山药是温州文成县特色农产品,因具独特的口感和保健功能成为市场的新宠,市场需求量日益增加。为了延缓鲜切糯米山药的褐变和品质劣变,采用不同质量分数的柠檬酸和维C分别对鲜切糯米山药进行保鲜处理,并真空包装,置于(4±1)℃的冰箱冷藏。以色泽Hunter L^(*)值、褐变度、多酚氧化酶和感官评分为考查指标进行单因素试验,筛选出对鲜切糯米山药保鲜效果最佳的柠檬酸和抗坏血酸质量分数。结果表明,鲜切山药最佳保鲜条件为柠檬酸保鲜剂质量分数0.8%,维C保鲜剂质量分数0.5%;0.5%维C保鲜效果总体上优于0.8%的柠檬酸;与清水对照组处理相比,2种保鲜剂可显著提高鲜切糯米山药贮藏过程中色泽亮度、降低褐变度、抑制多酚氧化酶的活性,延缓鲜切糯米山药的保鲜期,使鲜切糯米山药具有较好的感官品质。

不同保鲜剂组合对非洲菊切花保鲜效果的影响

以非洲菊(Gerbera jamesonii Bolus)鲜切花珍爱为试材,研究不同预处理液与瓶插保鲜液组合对丙二醛含量(MDA)、细胞膜透性、细菌含量及瓶插寿命的影响。结果表明,非洲菊切花经预处理液处理12 h后,MDA含量、细菌菌落数均显著低于对照(去离子水),且预处理能降低细胞膜的相对透性。非洲菊切花在瓶插处理期间MDA含量及细胞膜透性出现先下降后上升的变化趋势,瓶插14 d时达到最大值。花茎及瓶插液的细菌菌落数在瓶插过程中呈逐渐上升趋势,鲜花营养剂和免切通用鲜花营养液2种瓶插液表现了较好的抑菌效果。保鲜效果最佳的保鲜剂组合为可利鲜专业1号醒花液+鲜花营养剂,该处理可显著延长切花的瓶插寿命,其预处理及瓶插期间MDA含量、细胞膜透性和细菌菌落数的累积值均显著低于对照。

二氧化氯释放膜在鲜切火龙果保鲜中的应用

以亚氯酸钠和柠檬酸为主要原料,制备了气态二氧化氯(ClO_(2))释放膜,并探讨了在4℃下该释放膜对鲜切火龙果抑菌效果、氯残留及营养感官品质的影响。结果表明,在含有ClO_(2)释放膜的包装体系中,ClO_(2)的释放时间为24~28 h,最大释放量达0.44 mg/L。释放膜中亚氯酸钠和柠檬酸含量越高,ClO_(2)释放速率越大、释放时间越短。ClO_(2)释放膜可有效抑制细菌和酵母菌的生长。在经ClO_(2)释放膜处理的鲜切火龙果中检测到氯离子和氯酸盐两种氯残留化合物,其中氯离子含量在贮藏期显著上升,但氯酸盐残留量与对照组的无显著差异,该处理未造成基于氯残留的安全隐患。ClO_(2)释放膜可显著抑制火龙果可溶性固形物含量的下降,在贮藏期8 d时使得可滴定酸含量增加10%左右。ClO_(2)释放膜处理会造成火龙果中维生素C和总酚的损失,其中在贮藏期8 d时维生素C含量下降17%~32%,总酚的损失率可通过减少释放膜中亚氯酸钠和柠檬酸含量显著降低到27%以下。此外,ClO_(2)释放膜可显著抑制火龙果的褐变并降低POD活性。因此,ClO_(2)释放膜能够明显延长鲜切火龙果的贮藏期,使其维持较好品质。

中药材泽泻的商品规格等级划分现状调查与分析

目的:综合调研中药材泽泻规格等级现状,为进一步修订其商品规格等级标准奠定扎实基础。方法:综合文献调查、实地走访和通讯问卷法等调查方法,分析泽泻药材商品规格等级划分的历史沿革、标准现状及在产地、市场中的实际应用状况与关键问题。结果:泽泻按基原及产地划分为“川泽泻”与“建泽泻”两大商品规格,但目前市场上的主流商品川泽泻的基原植物却一直未被现有泽泻药材商品规格等级标准正式收载,同时市场上的泽泻趁鲜切制药材商品长期处于“有商品、无标准”的现状;在等级划分方面,缺乏体现泽泻药效的内在质量指标;除建泽泻,其它产地泽泻在实际加工和交易时均未参照现有标准,等级划分标准极不统一。结论:泽泻商品规格等级标准已不符合“基于药典”“基于市场”的基本原则,对生产、市场的规范及指导作用有限,建议应重点针对市场主流商品川泽泻及趁鲜切制药材作标准修订,以真正引导我国泽泻药材“优质优价”体系的形成,以“高标准”促进泽泻高质量产业健康发展。

基于智能凝胶标签的鲜切网纹瓜新鲜度无损监测

以卡拉胶、羧甲基纤维素钠和黄原胶为基质材料,溴百里香酚蓝(bromothymol blue,BTB)作为显色指示剂,复配一种新型凝胶状智能标签,用于鲜切网纹瓜新鲜度的实时监测。智能凝胶标签颜色随包装内CO_(2)浓度变化,由蓝色逐渐转变为黄绿色、黄褐色和橙黄色,从而反映鲜切网纹瓜的新鲜度。使用扫描电子显微镜、衰减全反射-傅里叶变换红外光谱、X射线衍射仪和热重分析仪对凝胶标签的形态和结构进行表征。结果表明,加入羧甲基纤维素钠和黄原胶未改变凝胶标签的微观结构,三者具有良好的相容性,同时凝胶标签的热稳定性随着BTB的加入得到提高。凝胶标签在4℃和25℃贮藏时,凝胶标签保持出色的颜色稳定性,将其用于鲜切网纹瓜4℃贮藏时,凝胶标签的颜色显示出明显的颜色变化。相关性分析表明凝胶标签色差值与包装中的CO_(2)浓度、鲜切网纹瓜的pH值和菌落总数均有显著相关性。该标签具有出色的pH值敏感性,可以作为监测鲜切网纹瓜新鲜度的有效方法。

LED光处理对鲜切果蔬品质影响的研究进展

鲜切果蔬因其方便、新鲜、安全等优点而受到消费者喜爱,但果蔬经切分处理会引发微生物侵染、褐变和货架期缩短等一系列问题。发光二极管(Light-emitting diode, LED)光处理技术能降低果蔬呼吸强度,延缓衰老,且因其成本低廉、绿色安全等优点在鲜切果蔬中应用广泛。综述了LED光处理对鲜切果蔬感官品质、生理品质和表面微生物的影响,以期为LED光处理技术在鲜切果蔬保鲜应用中提供理论参考。