不同储藏条件对牛肉品质的影响

为研究不同包装方式和储藏温度对牛肉品质的影响,以宰后24 h的牛背最长肌为材料,对其分别进行托盘、真空、涂膜3种方式包装,并置于（4±1） ℃冷藏及（-1.0±0.5） ℃冰温条件下储藏,并在储藏期间对牛肉的pH值、TVB-N含量、TBARS含量、微观结构以及挥发性成分进行检测。结果表明：储藏15 d后,冰温＋涂膜组牛肉的pH值和TVB-N含量最低,分别为6.23和11.59 mg/100 g;冰温＋涂膜组、冷藏＋涂膜组牛肉的TBARS值分别为0.35 mg/kg和0.39 mg/kg;电镜观察发现冰温＋涂膜组牛肉肌内膜结构相对完整,其他组都有不同程度松散和破坏;储藏期间牛肉中酮类、醛类、烃类、酯类物质的相对含量由低到高依次为：涂膜组＜真空组＜托盘组。综上所述,冰温储藏结合涂膜保鲜能更好地维持牛肉的品质,延长货架期。     

壳聚糖-nisin复合包装膜在烧鸡保鲜中的应用

研究壳聚糖- nisin复合包装膜处理对烧鸡保鲜的作用。采用3种包装形式（普通包装、1%壳聚糖膜、1%壳聚糖+0.02% nisin复合膜）对烧鸡进行处理,定期测定菌落总数、pH值、挥发性盐基氮（TVB-N值）、脂肪氧化（TBARS值）和感官评定。结果表明,在4℃条件下处理组样品货架期为7~14 d,对照组样品货架期约为3 d。低温贮藏过程中,处理样品的pH值、 TVB-N值、 TBARS值、菌落总数均显著低于对照组。     

两种不同保鲜剂处理对羊肉储藏品质的影响

以鄂尔多斯白山羊肉为试材，探究不同质量浓度抗菌保鲜剂ε-聚赖氨酸（0.10、0.15、0.20 g/L）以及乳酸链球菌素（0.1、0.2、0.4 g/L）处理对4℃条件下羊肉储藏品质的影响。结果表明：采用不同质量浓度的ε-聚赖氨酸进行处理时，在储藏前期，0.20 g/L处理组的保鲜效果较好，其高铁肌红蛋白较低，感官评分较高；在储藏后期，0.15 g/L处理组各项指标的储藏效果优于其他浓度处理组，其硬度平均值波动较稳定，同时维持肉品色泽及感官品质。采用不同质量浓度的乳酸链球菌素进行处理时，0.2 g/L的处理较其他浓度处理能够抑制高铁肌红蛋白含量的升高，维持肌肉硬度，延缓肌肉持水力的降低，维持较高的亮度值，且在储藏21 d后未腐败变质，与空白组相比能够有效延长羊肉的货架期约7 d。     

复配天然保鲜剂对青虾冷藏保鲜效果的影响

采用复配天然保鲜剂(保鲜剂中含有壳聚糖12.5 g/L,卡拉胶1.75 g/L,迷迭香提取物0.9 g/L,Nisin 0.7 g/L)对青虾进行保鲜处理,以青虾肌肉的pH值、挥发性盐基氮(TVB-N)值、硫代巴比妥酸反应物(TBARS)值和青虾菌落总数为指标,结合青虾肌肉蛋白质的SDS-PAGE电泳结果,分析复配天然保鲜剂对青虾4℃冷藏保鲜效果的影响.结果表明:与对照组相比,采用复配天然保鲜剂处理能延缓青虾冷藏期间肌肉pH值、TVB-N值、TBARS值和菌落总数的增长;SDS-PAGE图谱表明,该复配天然保鲜剂有利于维持青虾肌肉蛋白质结构和性质的稳定性.以上结果说明,在4℃冷藏条件下,复配天然保鲜剂处理青虾能够抑制其蛋白质降解、脂肪氧化酸败和微生物的生长,从而延缓青虾的腐败变质,货架期达到7 d,保鲜效果良好.     

大孔树脂纯化襄荷黄酮提取物及其对小鼠运动性疲劳的影响

采用大孔树脂纯化襄荷黄酮提取物,比较树脂之间静态吸附与洗脱性能的差异,确定最佳型号树脂的吸附机理后,采取动态吸附与洗脱试验确定最佳纯化工艺,另通过动物实验考查纯化后的襄荷黄酮抗疲劳活性.结果 表明,AB-8型大孔树脂为纯化襄荷黄酮的最佳树脂,饱和吸附量随上样浓度的升高逐渐增大,但随温度升高而逐渐减小,等温吸附线符合Langmuir模型特征,最佳纯化工艺条件为:60 mL上样浓度为6 mg/mL襄荷黄酮(pH 6.0),上样流速3 mL/min,洗脱流速2 mL/min,洗脱液乙醇浓度60％,洗脱液体积150 mL,产物的黄酮纯度由11.25％提高至47.52％.动物实验结果显示,中、高剂量的纯化产物可明显延长小鼠的负重游泳时间,降低运动后体内乳酸与尿素氮浓度,并提高乳酸脱氢酶的活力,因此可较好地缓解运动性疲劳.     

不同壳聚糖抗菌膜对草鱼保鲜效果的比较

本试验比较不同壳聚糖抗菌膜对草鱼鱼片的保鲜效果。试验以壳聚糖作为成膜材料,以葱、姜、蒜乙醇提取液作为抗菌剂,制备了4种涂膜液（壳聚糖、壳聚糖＋葱、壳聚糖＋姜、壳聚糖＋蒜）,以蒸馏水作为对照,对草鱼鱼片浸渍涂膜后进行冷藏保存（8℃）,分别在冷藏0、3、6天时取样,对鱼片进行感官分析,测定鱼片的细菌总数、挥发性盐基氮（TVB-N）和pH值。试验结果为4 种涂膜液组鱼片的感官评分均显著高于对照组,而细菌总数、TVB-N和pH显著低于对照组;壳聚糖＋葱、壳聚糖＋蒜组的感官评分显著高于壳聚糖组,而细菌总数、TVB-N和pH之显著低于壳聚糖组。试验结果表明,壳聚糖涂膜利于草鱼鱼片的贮藏,添加葱、蒜提取液可提高壳聚糖涂膜的保鲜效果。     

复合香辛料提取物对冷藏猪肉糜氧化及品质特性的影响

为探究桂皮、生姜、八角茴香复合香辛料提取物对冷藏期间猪肉糜氧化稳定性及品质的影响,分别向猪肉糜中加入浓度为0.3%、0.7%、1.1%的香辛料提取物溶液,测定不同处理组的硫代巴比妥酸值（Thiobarbituric acid reactive substances,TBARS）、蛋白质羰基、总巯基、pH、蒸煮损失、色差、质构特性等指标,并通过电镜观察其微观结构。结果表明：添加复合香辛料提取物的猪肉糜TBARS值、羰基含量和巯基损失量显著低于空白组（P＜0.05）,添加浓度为0.7%和1.1%两组间无显著差异;与空白组相比,冷藏后期3个不同提取物浓度组肉糜的pH、蒸煮损失、L*值、a*值、质构特性均有显著改善（P＜0.05）,并降低了因氧化诱导引起的微观结构的改变,但1.1%浓度组肉糜a*值较其他浓度组低（P＜0.05）,说明高浓度的复合香辛料提取物对肉糜色泽有一定的负面影响。综上所述,添加浓度为0.7%的复合香辛料提取物可有效抑制冷藏猪肉糜的氧化和品质的劣变。     

不同光照处理对金枪鱼新鲜度的影响

以冷藏金枪鱼前腹肉为试材,托盘包装后置于4℃冷柜中,经700 Lux光照强度的不同光源(红光(波长630 nm)、绿光(波长530 nm)、紫光(波长400 nm))照射处理4 d后测定L~*值等理化指标。结果表明,不同光源照射对金枪鱼新鲜度的变化有显著影响,供试波长越长,越有利于保持冷藏金枪鱼的新鲜度;红光照射的效果最好,可考虑做为金枪鱼展柜的光源;红光照射金枪鱼4 d后的L~*值、a~*值、硫代巴比妥酸反应产物(TBARS)值、高铁肌红蛋白(Met Mb)相对百分含量和鱼肉鲜度K值分别为32.27、7.11、0.89 mg/100 g、30.34%和12.96%。     

酸性电解水对冰鲜鸽保鲜效果的研究

以刚宰杀急速冷却的鸽子为研究对象,用酸性电解水处理后进行0~4 ℃冷藏保鲜,通过测定鸽肉的pH、挥发性盐基氮（TNB-N）含量、菌落总数、汁液流失率及感官评价等指标,研究酸性电解水电解时间、浸泡时间及pH对冰鲜鸽保鲜效果的影响。结果表明：酸性电解水能有效抑制冰鲜鸽肉中微生物的生长繁殖,在一定程度延缓TNB-N含量、汁液流失率、pH的上升。在0~4 ℃冷藏条件下,对照组鸽肉可以保存5 d,经pH 2.65的酸性电解水浸泡15~20 min后的鸽肉能保存7~9 d,延长了2~4 d的保质期。     

电子束辐照对储藏期间三文鱼鲜度的影响

为探究电子束辐照技术对三文鱼保鲜效果的影响,以新鲜三文鱼为原料,经不同低剂量（0~4 kGy）电子束辐照结合真空包装处理,研究4 ℃储藏条件下三文鱼的鲜度变化情况。以微生物菌落总数（Total bacterial counts, TBC）、挥发性盐基氮（Total volatile base nitrogen,TVB-N）含量及鲜度值（K值）为指标,并结合感官评价（Sensory assessment, SA）对三文鱼的鲜度进行综合评定,同时对各鲜度指标进行了相关性分析。结果表明,辐照剂量越高,杀菌效果越好;电子束处理后的三文鱼K值和TVB-N含量随贮藏时间的延长均呈现不同程度的增加,且冷藏期内其K值、TVB-N含量的上升速度均低于对照组;低剂量辐照对三文鱼感官品质影响不明显,其中经2、4 kGy辐照处理的三文鱼虽有一定的保鲜效果,但同时伴有色泽变淡,轻微辐照异味产生的现象。综合考虑,电子束辐照处理三文鱼的最佳辐照剂量为1 kGy,相应的货架期可达到12 d,与对照组相比,延长了6 d左右。同时三文鱼的K值与菌落总数、感官评分均具有极显著的相关性（P＜0.01）。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.