暗纹东方鲀冻藏品质劣化的原因解析

通过比较冰晶、内源蛋白酶以及氧化对冻藏暗纹东方鲀(Takifugu obscurus)品质的影响，确定冻藏暗纹东方鲀品质劣化的关键因素。实验通过液氮浸渍快速冻结抑制鱼肉组织中冰晶增长、碘乙酸浸泡前处理抑制鱼肉内源蛋白酶活性、复合抗氧化剂浸泡前处理抑制蛋白/脂质氧化作用的设计，区分冰晶、内源蛋白酶和氧化3种因素对冻藏鱼肉品质的影响；并以硬度、解冻流失率、蒸煮损失率、挥发性盐基氮含量、K值、Ca2+-ATPase活性、肌原纤维小片化指数和肌纤维长度作为鱼肉品质的评价指标。结果显示，冻结过程中控制冰晶增长对暗纹东方鲀冻藏品质的改善作用最大，冻藏24周后，速冻组的硬度比内源蛋白酶抑制组和氧化抑制组分别提高了26.8%和20.5%，解冻流失率分别降低了44.2%和44.8%，且该处理组TVB-N、K值和Ca2+-ATPase活性变化更慢，24周后分别为10.5 mg/100 g、6.8%和1.43 μmol Pi/mg/10 min。综合各项指标发现，冰晶、内源蛋白酶和氧化对冻藏暗纹东方鲀品质劣化均有影响；其中，冰晶作用是导致暗纹东方鲀在冻藏过程中品质下降的最主要影响因素，内源蛋白酶和氧化对冻藏暗纹东方鲀品质的影响次之，且二者对品质影响无显著性差异。     

Response of Scotian Shelf silver hake (Merluccius bilinearis) to environmental variability

Commercially‐exploited fish populations are not only shaped by fishing pressure, but also by the dynamics of their environment. By quantifying the influence of environmental variability, fisheries management advice can be improved and uncertainties reduced. To this end, we developed statistical models of the response of Scotian Shelf silver hake stock metrics to variability in zooplankton community composition and phenology over the past 18 years and in the physical environment since 1985. Dominant modes of variability in these pelagic habitat indicators were characterized using principal component analysis, and the relationships of silver hake condition, abundance, and recruitment to pelagic habitat variability were assessed using generalized additive models. Condition was largely modulated by the onset and duration of the spring bloom, which controls food availability. In contrast, adult abundance was governed by composition of the zooplankton community and bottom‐water temperature, which dictates the distribution of silver hake. Finally, recruitment was affected by both thermal conditions and food availability. Our results presented here form the basis for qualitative assessment of ecosystem attributes and the influence on silver hake stock productivity.     

The effects of utilization of hazelnut oil,sunflower oil and their products on performance and fatty acid composition of yolk in layer hens

This research has been performed to determine the effects of hazelnut crude oil, sunflower crude oil and its refinery by-products over the laying hens performance and the fatty acid composition of the egg’s yolk. Four hundreds 36-week-old Nick Brown layer hens were allocated into five groups. Treatment groups were supplemented with 1.5% of sunflower crude oil, hazelnut crude oil, acidulated sunflower soapstock, acidulated hazelnut soapstock and acidulated hazelnut crude oil. The daily feed consumption for groups that were fed with crude oils were numerically improved as compared for those nourished with acidulated soapstocks. Although the percentages of cracked and broken eggs in acidulated hazelnut soapstock group was significantly higher than the other groups, daily feed consumption and egg production values were not different. The usage of acidulated hazelnut soapstock reduced the percentage of intact egg ratio. Egg’s specific gravity and yolk color index were the highest level throughout the experiment from start to end in hazelnut crude oil group (p < 0.05). In group that was nourished by hazelnut oil, Omega 3/Omega-6 fatty acid ratios in egg yolk were higher than the groups that were fed with sunflower oil. The oleic acid content of the egg yolk was increased in the groups which were supplemented with hazelnut crude oil and acidulated hazelnut crude oil. Consequently, hazelnut crude oil and acidulated hazelnut crude oil improved the egg shell quality, yolk color index and yolk oleic acid value which would increase egg’s shelf life. On the other hand acidulated hazelnut soapstock supplementation adversely affects the quality of egg shell.     

Pericarp total protein profiles as molecular markers of tomato fruit quality traits in two segregating populations

The tomato fruit quality results of biochemical and physiological changes that occur during the ripening process. Although, the pericarp total protein profiles are less polymorphic than DNA-based markers the polymorphism in those could be directly associated with fruit quality traits. The aim of this work was to identify associations between polymorphic polypeptides from fruit pericarp at two ripening stages and fruit quality traits evaluated in two segregating populations of tomato. A cross between a normal ripening cultivar of Solanum lycopersicum (C, Caimanta) and a genotype carrying the nor (non ripening) gene (N) as well as a cross between Caimanta and a cherry type tomato of S. lycopersicum var. cerasiforme (Ce) showed genetic variance for several fruit quality traits such as fruit weight, shape, solids soluble content, acidity, color and fruit shelf life. The quantitative variations observed at phenotypic level had correspondence with the polymorphism detected in the protein profiles. Indeed, the polymophic polypeptides associated with quality fruit traits and fruit shelf life would be useful to assist tomato breeding programs as protein molecular markers.     

Effects of ultrasound and high pressure argon on physico-chemical properties of white mushrooms (Agaricus bisporus) during postharvest storage

Effects of high pressure argon (H), ultrasound (U) and their combination treatments (UH) on physico-chemical characteristics of white mushrooms were studied during 9 d of postharvest storage at 4 °C. H treated samples exhibited the smallest weight loss and respiration rate compared to all other samples. Mass losses after 9 d of storage were 3.01%, 5.09%, 5.39% and 9.59% for H, UH, U and untreated mushrooms, respectively. Furthermore, U treated samples showed lower polyphenol oxidase activity (PPO, E.C. 1.14.18.1) during storage while UH treated samples showed a slight increase in antioxidant capacity during storage and also experienced reduced mass loss and respiration rate. In addition, treated samples were effective in retaining mushrooms colour changes compared to control. Physico-chemical properties of differently treated mushrooms (UH, H and U) stored at 4 °C were significantly different (p < 0.05) from control.     

Effects of Low Temperature Stress and INA Bacteria on Chlorophyll a Fluorescence Induction Kinetics in Young Fruit of Two Apricot Cultivars

Effects of low temperature and INA bacteria on the change of chlorophyll a fluorescence inyoung fruit from two apricot cultivars were investigated. Low temperature decreased the potential activity(Fv/Fo) ,conversion efficiency of primary light energy (Fv/Fm)of PS Ⅱ and photochemical quenching (qP) inyoung fruit of two apricot cultivars. Low temperature enhanced non-photochemical quenching qN, decreasingthe quantum yield of photosynthetic electron transfer. The presence of ice nucleating active (INA) bacteria in-tensified the effects of low temperature, raised the injury temperature threshold from - 4℃ to - 2 - - 3℃.INA bacteria can be a factor to induce frost susceptibility of apricot fruit. The amount of damaged PS Ⅱ activi-ty center was related to apricot fruit size and cultivar.     

黄河凌汛检测系统分析

根据清洁水体、浑浊水体和冰体在不同波段的反射率不同,运用C语言编写黄河凌汛检测系统程序,将清洁水体、浑浊水体和冰体检测出来,运用GIS的地图控件计算出清洁水体、浑浊水体和冰体面积以及它们的中心经纬度,以实现对黄河凌汛的动态检测。     

云南诱发霜冻害冰核活性细菌的鉴定

 1990年冬,从云南省宾川、大理、昆明、陆良等地采集受霜冻危害小麦、蚕豆、蕃茄上的33个标样,分离出12个冰核活性的细菌菌株.鉴定结果是Erwinia herbicola waranaanas及Pseudomonas syrindae.首次证明云南有冰核活性细菌.     

冰核活性细菌对黄粉虫幼虫耐寒性的影响

采用水浴和喂食两种接种方法,研究了冰核活性细菌(INA细菌)分别在不同接种浓度下对储粮害虫黄粉虫幼虫体内物质及耐寒性的影响。结果表明,分别用水浴法和喂食法接种不同浓度的INA细菌菌株S2和S24后,黄粉虫幼虫的耐寒性均显著降低,其体内脂肪、糖原和血糖含量也显著或极显著降低。同时,INA细菌水浴法接种的效果优于喂食法;INA细菌高浓度接种效果高于低浓度;菌株间,只有在用浓度为3×108cfu/ml水浴法接种时,菌株S24的效果优于菌株S2。说明利用INA细菌可显著提高储粮害虫黄粉虫越冬期间的死亡率。     

Bio-based Coating from Fish Gelatin,K-Carrageenan and Extract of Pomegranate Peels for Maintaining the Overall Qualities of Fish Fillet

ABSTRACT

To maintain the overall quality of fisheries products, functional edible coatings from natural ingredients including fish gelatin (Gf), k-carrageenan (Cr), and extract of pomegranate peels (PPE) were composed. The Gf was extracted from blue tilapia (Oreochromis aureus), microencapsulated with Cr, and then loaded with PPE (at concentrations of 0.5%, 1.0%, 1.5% and 2.0%). The Fourier transform infrared (FTIR) spectra of Gf/Cr composites verified their cross-linkage and functionality; the Gf/Cr microcapsules had a mean particle size of 36.2 µm with good distribution and homogeneity. The coating of Nile tilapia (Oreochromis niloticus) fillets, with constructed solutions from Gf/Cr/PPE, revealed their positive effects on fillet quality attributes; the effectiveness was dependent on the supplemented PPE concentration. The Gf/Cr/PPE solutions could effectively reduce the microbial counts of total aerobics, psychrotrophs, yeast and molds, and enterobacteriaceae groups throughout 30 days of refrigerated storage. Additionally, the analysis of spoilage chemical parameters (total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substances) in coated samples indicated that formulated solutions could hinder the increase of their values during storage. The sensorial evaluation indicated the acceptability and validity of coated samples for up to 30 days of storage. Gf/Cr/PPE coating is recommended for overall quality maintenance of fish fillets and prolongation of storage using safe and healthy biopreservatives.