Effect of sustained deficit irrigation on physicochemical properties,bioactive compounds and postharvest life of pomegranate fruit (cv. ‘Mollar de Elche’)

In this study, the influence of sustained deficit irrigation (SDI; 32% of reference evapotranspiration (ET₀)) on physicochemical and sensory quality and bioactive compounds of pomegranates stored for 30, 60 and 90 days in air at 5 °C + 4 days at 15 °C, at each storage period, was studied and compared to a control (100% ET₀). Fruit from SDI had higher peel redness and greater firmness, soluble solids contents, vitamin C (27%), phloretin (98%) and protocatechuic acid (10%) levels, and total antioxidant capacity (TAC) (46%) than the control. Cold storage and shelf-life did not induce significant changes in soluble solids, pH, titratable acidity, and chroma and Hue. SDI fruit had retarded development of chilling injury (CI) symptoms, which appeared after 60 days of storage in comparison to 30 days in the controls. Anthocyanins, catechin, phloretin and protocatechuic, caffeic, p-coumaric and caffeic acids contents had greater increases in SDI fruit than in controls throughout the postharvest life. TAC was significantly (P < 0.05) correlated to anthocyanins, gallic acid and total vitamin C contents. Generally, after long term storage, the fruit grown under SDI showed higher sensory and nutritional quality, more health attributes and a longer shelf-life (up to 90 days at 5 °C + 4 at 15 °C) than fruit irrigated at 100% ET₀.     

Effect of atmospheres combining high oxygen and carbon dioxide levels on microbial spoilage and sensory quality of fresh-cut pineapple

Fresh-cut fruit such as pineapple have a very limited shelf-life. The study aims at prolonging the shelf-life of fresh-cut pineapple by means of modified atmospheres (MAs). The effect of MAs combining high O₂ (21–70%) and CO₂ (21–50%) levels on microbial spoilage and sensory quality of fresh-cut pineapple was therefore evaluated. In the first part of the study, the behaviour of two spoilage yeasts (Candida sake and Candida argentea) and one lactic acid bacterium (Leuconostoc citreum), which had previously been isolated from spoiled commercial fresh-cut pineapple cubes, were monitored on pineapple agar separately. In the second part of the study, the shelf-life of commercial fresh-cut pineapple cubes packaged in selected MAs was evaluated at 7 °C. The results showed that MAs combining high O₂ and high CO₂ levels had a large inhibitory effect on the growth and volatile metabolite production of C. sake and C. argentea on pineapple agar. A MA with 50% O₂ and 50% CO₂ was in both cases the most inhibitive. Although MAs induced the production of ethyl acetate by the yeasts, the quantity of ethyl acetate was much lower in high O₂ and high CO₂ than that in air due to lower yeast population density in MAs. With regards to growth, L. citreum was not sensitive to high O₂ and CO₂ levels. The fresh-cut pineapple packaged in air had deteriorated and were not acceptable any more by day 7, while those packaged in 50% O₂ combined with 50% CO₂, which also retarded the growth of aerobes and yeasts on pineapple cubes during storage, were still acceptable. It can be concluded that a MA with 50% O₂ and 50% CO₂ shows the best potential for extension of the shelf-life of fresh-cut pineapple.     

泵站多功能压力集测仪

介绍了一种适用于泵站和电站的测量多种压力量和在压力管道的收缩段或弯头处利用差压法测量流量的智能仪器的原理和构成，可对双路测试通道进行巡测，能适应不同量程及与不同输出量的传感器配套使用，并且具有通讯及打印输出功能。     

乙醇水溶液提取樟树叶活性成分工艺及其成分分析

以樟树叶提取率为响应值,采用单因素试验和响应面法对提取时间、提取温度、液料比和乙醇体积分数4个影响因素进行优化选择,确定最优工艺参数;而后利用顶空固相微萃取-气相色谱-质谱法对所得提取物进行成分分析。结果表明:各因素对樟树叶提取率的影响由大到小依次为液料比、提取时间、提取温度、乙醇体积分数,其中液料比属极显著影响因素;樟树叶提取最优工艺参数为乙醇体积分数45%,提取温度58℃,提取时间78 min,液料比16(m L)∶1(g),平均提取率达到19.33%;提取的樟树叶提取物中含有大量醇烯化合物,其中异丁香酚甲醚(18.42%)、芳樟醇(11.59%)、反式-橙花叔醇(10.40%)、丁香酚甲醚(6.37%)等都是经济价值较高的化合物。     

河源独头火蒜与独头蒜挥发成分测定

[目的]了解河源火蒜与普通蒜的香气成分差异。[方法]采用静态顶空进样-气相色谱-质谱联用法(SHS-GC-MS)对河源独头火蒜和独头蒜的挥发性物质及含量进行分析。[结果]该试验条件下,共检出独头蒜挥发性风味成分主要有23种,12种为含硫化合物,其中主要成分是二烯丙基三硫醚(25.11%)、二烯丙基二硫醚(19.78%)、3,4-二甲基-1,2-二硫环戊烯酮(18.65%)、二氧化硫(5.20%)、3-乙烯基-1,2-二硫环戊烯(2.61%)、烯丙基甲基硫醚(2.31%)、2-乙烯基-1,3-二噻烷(2.07%)、2-恶唑烷硫酮(2.00%)、甲硫基乙腈(1.78%)、硫氰酸乙酯(1.28%),共占总含量81.73%;共检出独头火蒜主要挥发性风味成分也为23种,14种为含硫化合物,其中主要成分是二烯丙基三硫醚(38.03%)、二烯丙基二硫醚(22.63%)、3-乙烯基-1,2-二硫环戊烯(7.95%)、3,4-二甲基-1,2-二硫环戊烯酮(7.55%)、二氧化硫(4.08%)、甲硫基乙腈(4.04%)、二烯丙基硫醚(2.99%)、异硫氰甲酸甲酯(2.08%)、硫氰酸乙酯(1.49%)、烯丙基甲基硫醚(1.41%)、硫化丙烯(1.25%)、2-乙烯基-1,3-二噻烷(1.15%),共占总含量95.59%。[结论]河源独头火蒜的挥发性物质的数量和含量比普通独头蒜都高。     

东北黑熊不同基因组DNA模板来源的比较研究

文章主要探讨使用黑熊毛发作为试验材料替代其他生物样品进行遗传多样性研究的可行性,筛选满足试验需求的最佳使用量.以延边白头山制药有限公司养熊场的4头成年东北黑熊为试验材料,分别5次拾取2头黑熊铁笼内散落的带有毛囊的50、100根毛发,对麻醉的2头黑熊抽取全血3 mL以及皮下结缔组织1 g,并分别采用不同方法提取基因组DNA.以微卫星位点ABB12和UT35为引物,设置20、50、100 ng·μL-13种模板浓度进行PCR扩增.结果显示,采用50 ng·μL-1的模板浓度均可获得较好的PCR产物,采用聚丙烯酰胺凝胶电泳对扩增基因具有较好的分辨效果.毛发DNA、血液DNA和组织DNA的PCR产物数量和质量并无明显差异.毛发数量与所提取的DNA浓度有一定关系.利用15个毛发DNA的PCR产物进行聚丙烯酰胺凝胶电泳,均可观察到清晰的条带.研究结果进一步证明毛发DNA可作为东北黑熊遗传多样性研究的试验材料.     

赤霉素对休眠微型薯多酚氧化酶的影响

为了明确赤霉素对微型薯休眠及其酚类物质的影响。对赤霉素处理后20 d的微型薯发芽率及其酚类物质进行测定。结果表明：赤霉素能够显著地提高微型薯的发芽率，其中50 mg·L^-1GA3处理的微型薯发芽率最高，达98.1%，显著高于对照66.8%；酚类物质的测定结果表明，赤霉素浓度在50 mg·L^-1左右时，多酚氧化酶活性最低，酚类化合物的总含量相应最低，为325.0μg·g^-1.FW；酚类化合物中对微型薯休眠起主要作用的为儿茶酚和咖啡酸。     

二氧化硅/木材复合材料的动态黏弹性

为弄清二氧化硅/木材复合材料的动态黏弹性,通过动态热机械分析仪研究不同增重率的二氧化硅/木材复合材料松弛过程的转变温度及力学损耗角正切的变化.结果表明:二氧化硅/木材复合材料的松弛过程数量减少,直接溶胶-凝胶法制备的二氧化硅/木材复合材料,α松弛过程的转变温度随着增重率的增加而向高温方向移动.增重率为0,5.10%和28.00%的α松弛过程的转变温度分别为75.2,76.8和93.6℃;α松弛峰的峰值减小,增重率为0,5.10%,12.63%和28.00%的α松弛过程的损耗角正切值分别为0.043,0.041,0.033和0.03.加硅烷偶联剂法制备的二氧化硅/木材复合材料,随着增重率的增加,α松弛过程的起始温度向低温方向移动,增重率为6.61%,8.08%和10.58%的α松弛过程的起始温度分别为44.9,41.0和32.2℃.     

Alpha-amylase treatment increases extractable phenolics and antioxidant capacity of oat (Avena nuda L.) flour

In this work, α-amylase was used to treat oat flour with the intent to release phenolic compounds with known antioxidant properties. After methanol extraction, the amounts of nine beneficial phenolic compounds were measured using HPLC. The antioxidant activities of the extracts were assessed using 2,2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS)，2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and protein oxidative damage protection assays. Compared with heating-only treated oat flour, that treated with α-amylase showed significant increase of extractable total phenolic content (0.46–1.35 μmol gallic acid equivalents per gram oat), total antioxidant capacity, and an increased ability on the protection of protein from oxidative damage. Heating-only increased caffeic acid and vanillin content by 17 (0.03 vs 0.54 μg/g oat) and 1.8 (0.62 vs 1.11 μg/g oat) folds, but slightly increased the content of other phenols. Excluding heating effect, α-amylase treatment increased gallic acid content by 2.6 folds (0.38 vs 1.38 μg/g oat), caffeic acid content by 2.4 (0.54 vs 1.82 μg/g oat) folds, and other phenols by 1.0–1.8 folds. In conclusion, α-amylase treatment can yield oat products containing more extractable phenolic compounds with increased antioxidant capacity.     

The potential for using cyanobacteria (blue-green algae) and algae in the biological control of plant pathogenic bacteria and fungi

Cyanobacteria (blue-green algae) and eukaryote algae occur in freshwater, marine, and terrestrial (soil) habitats. In fact, these microorganisms comprise most of the world's biomass. Although the cyanobacteria are mostly photoautotrophic, some are facultative heterotrophs, capable of growing on certain substrates in darkness. Also, some are non-phototrophic and hence, are obligate heterotrophs. A number of cyanobacteria and eukaryote algae, particularly macroalgae, produce various, biologically active compounds. These include antibiotics which in laboratory tests inhibited bacteria and fungi that incite diseases of humans. In addition, the following fungi which are of interest to plant pathologists, were inhibitedin vitro by substances produced by various cyanobacteria: The saprophytesChaetomium globosum, Cunninghamella blakesleeana, andAspergillus oryzae and the plant pathogensRhizoctonia solani andSclerotinia sclerotiorum. Extracts from seaweeds (macroalgae) sprayed on plants have been reported to reduce the incidence ofBotrytis cinerea (gray mold) on strawberries,Erysiphe polygoni (powdery mildew) on turnips, and damping-off of tomato seedlings. Because many cyanobacteria and algae produce a large number of antibacterial and antifungal materials, are almost never a threat to the environment, and many can be grown in quantity in mass culture, they are suitable candidates for exploitation as biocontrol agents of plant pathogenic bacteria and fungi. Much additional work remains to be done however, to thoroughly evaluate cyanobacteria and algae and their products for this role.