壳聚糖-植酸复合膜的制备及其对鲈鱼片保鲜品质的影响

以壳聚糖为成膜剂,植酸为抗氧化剂,并添加丙三醇制备一种具有保鲜性能的壳聚糖-植酸复合膜。以复合膜的拉伸强度、断裂拉伸率、水蒸气透过系数、透光率为考察指标,进行单因素试验,再以拉伸强度为响应值,运用Design Expert 软件对壳聚糖添加量、植酸添加量、丙三醇添加量进行三因素三水平响应面试验设计。以感官品质、色差、电子鼻分析为指标,探究复合膜对鲈鱼保鲜风味效果的影响。结果表明,复合膜的最佳工艺配方为：壳聚糖添加量1.5 g/100 mL,植酸添加量0.06 g/100 mL,丙三醇添加量0.225%。此条件下制成的复合膜工艺最好,拉伸强度可达29.281 MPa。由该复合膜包裹的鲈鱼片可以保持较高的感官品质,有效控制L*、a*值的降低和b*值的升高。采用电子鼻进行气味检测,发现随着储藏时间的延长,PE保鲜膜包裹的鲈鱼肉响应强度大于复合膜组。按最优配方制备的壳聚糖-植酸复合膜对鲈鱼片具有一定的保鲜效果。     

鼠尾草酸米糠蛋白复合膜的制备及性能研究

开发具有生物活性的鼠尾草酸可食性米糠蛋白复合膜,并研究其物理性能、结构及抗氧化活性。以米糠分离蛋白为成膜基质,添加鼠尾草酸制成复合膜,通过检测抗拉强度测试其机械性能,通过测定水蒸气透过率、透光率,通过扫描电镜等手段阐明其组织结构,并通过氧自由基清除能力判断其抗氧化性,研究和探讨鼠尾草酸米糠蛋白复合膜的理化性能。鼠尾草酸添加量在0~0.8%(W/V)时,随着添加量的增加,复合膜的透明度升高,颜色逐渐加深变为墨绿色,抗拉强度和断裂伸长距离均先升高后降低;0.5%鼠尾草酸添加量下米糠蛋白复合膜具有最大抗拉强度(984 g)和最长断裂距离(5.89 mm)。添加鼠尾草酸的米糠蛋白复合膜水蒸气透过率比未添加对照组有所提高,可见该膜具有较好的组织结构。添加鼠尾草酸的米糠蛋白复合膜,随着添加量的增大,该复合膜的自由基(DPPH·)清除活性提高,该复合膜的抗氧化活力(p0.05)显著提高。结果显示,所制备的鼠尾草酸米糠蛋白复合膜具有抗氧化性能,可应用于包装行业。     

壳聚糖对葡萄涂膜保鲜的应用研究

以葡萄为保鲜对象,采用涂膜法研究壳聚糖复合溶液对葡萄的保鲜效果。通过比较流延膜的力学、阻隔和透明等性能以及对葡萄的保鲜效果,确定壳聚糖、醋酸、丙三醇、山梨酸钾的最佳添加量。结果表明,壳聚糖复合膜的保鲜效果主要受p H值和壳聚糖溶解性影响;由壳聚糖添加量1.5%,醋酸添加量1%,丙三醇添加量0.5%,山梨酸钾添加量0.5%组成的壳聚糖复合膜对葡萄的保鲜效果最佳,相对于空白组延长了保鲜期5 d。     

扁实柠檬汁抗氧化活性及其对冷鲜肉保鲜效果的研究

以NFC扁实柠檬汁为试材,测定了扁实柠檬汁对羟基自由基和DPPH自由基的清除能力及其VC和总黄酮含量,并将10%扁实柠檬汁分别与0.05 mg/m L合成多肽AMP-D、0.1%茶多酚配制复合保鲜剂,研究其对冷鲜肉的保鲜效果。结果表明,扁实柠檬汁对羟基自由基和DPPH自由基具有较好的清除能力,其中对DPPH自由基的清除能力强于对羟基自由基的清除能力,扁实柠檬汁对自由基的清除效果受温度影响不大,具有较好的抗氧化性;扁实柠檬汁中的VC和总黄酮含量较高,VC含量随储藏温度的升高逐渐降低,总黄酮含量在35℃以内受温度影响不大;10%扁实柠檬汁分别与0.05 mg/m L合成多肽AMP-D、0.1%茶多酚配制的复合保鲜剂对冷鲜肉有一定的保鲜作用,与对照相比,在储藏温度4℃下,能够将肉样一级鲜肉等级延长4 d,在储藏温度15、25℃下,可延长鲜肉品质1 d。     

京尼平交联乳清蛋白和壳聚糖膜的制备

以乳清蛋白和壳聚糖为原料制备复合膜,同时利用天然无毒的京尼平作为交联剂,研究其制备工艺。通过单因素试验研究成膜材料比例、热处理温度、塑形剂、交联剂对乳清蛋白和壳聚糖复合膜性能的影响,并对复合膜进行表征和抑菌性研究。结果表明,京尼平可以作为交联剂用来制备乳清蛋白和壳聚糖复合膜,并且可以较好地改善复合膜的拉伸性能和阻隔性能,膜制备的最佳工艺条件是乳清蛋白(WPC)与壳聚糖(CS)配比为6:4,甘油添加量4%,热处理温度70℃,京尼平添加量0.4%,此时复合膜的拉伸强度(TS)1.79 MPa,断裂伸长强度(E)30.28,透光率(T)37%,水蒸气透过率(WVP)1.25,溶解性(S)34%。在此条件下制得的复合膜具有良好的阻隔性能、抗拉强度、致密性和抑菌性能,可用于食品保鲜和抗菌内外包装的使用。     

菜籽饼中植酸粗提液的体外抗氧化能力初探

研究了3种不同溶剂体系提取菜籽饼中植酸粗提液的体外抗氧化性能力。通过Fenton反应体系产生羟自由基(.OH),由连苯三酚在碱性溶液中自氧化反应产生超氧阴离子自由基(O2-.);用分光光度法检测3种植酸粗提液的还原能力及对.OH、O2-.和DPPH.的清除作用。结果表明,3种溶剂提取得到的植酸粗提液都具有还原能力;对羟自由基、超氧阴离子自由基、DPPH自由基也有一定的清除能力。     

主成分分析法结合响应面优化亚麻籽胶与壳聚糖复合膜成膜工艺

为优化亚麻籽胶与壳聚糖复合膜的成膜工艺，以亚麻籽胶和壳聚糖为主要材料制备复合膜，研究亚麻籽胶膜液∶壳聚糖膜液(V/V)、壳聚糖质量浓度和甘油添加量对复合膜性能的影响，并以复合膜性能综合评分为考察指标，结合主成分分析法和响应面试验法，优化复合膜制备工艺参数。结果表明，复合膜最优制备工艺为：亚麻籽胶膜液∶壳聚糖膜液(V/V)为20∶10，壳聚糖质量浓度1.0 g/100 mL，甘油质量分数21%；在此条件下制备的复合膜性能综合评分为0.724，膜的各项指标分别为：拉伸强度(18.16±0.17)MPa，断裂伸长率57.15%±0.14%，水蒸气透过率(1.30±0.02)(g·mm)/(h·m²·kPa)，氧气透过率(7.30±0.08)cm³/(m²·d·Pa)，透光率95.55%±0.09%。该研究结果可为复合膜在食品保鲜中的应用提供理论基础。     

圣女果酵素的制备工艺及抗氧化性质研究

以圣女果为原料,以SOD酶活及总酸为检测指标,用液态分步发酵法制备圣女果酵素。优化分步发酵的工艺条件,并对圣女果酵素的抗氧化性质进行研究。结果表明,水添加量50%,白砂糖添加量20%,发酵温度32℃,活性干酵母接种量0.5%,pH值4.1,发酵时间16 h进行一次发酵;发酵温度30℃,乳酸菌接种量0.1%,pH值5.0,发酵时间36 h进行二次发酵。此时发酵效果最好,SOD酶活可达324 U/mL,总酸含量为0.219 g/mL.该圣女果酵素对DPPH自由基的清除能力超过了维C,对羟自由基的清除能力接近维C,但对超氧阴离子的清除能力低于维C。     

壳聚糖复合膜对黄瓜货架期保鲜的研究

以山梨酸钾、壳聚糖、酒石酸为保鲜剂,进行L9(34)正交试验,分析不同配比的壳聚糖复合膜对黄瓜进行涂膜保鲜性能的影响。通过测定其货架期间的失水率、硬度、可溶性固形物、呼吸强度,叶绿素及VC含量等指标以研究保鲜效果。结果表明,壳聚糖复合膜的膜特性良好,涂布均匀,可有效保持黄瓜的感官质量,降低黄瓜的失质量率和硬度,抑制其呼吸强度,减少可溶性固形物、叶绿素和VC含量的损失。其中以2.0%山梨酸钾、1.5%壳聚糖、1.5%酒石酸为配比的复合膜保鲜效果最好。     

交联羧甲基纤维素-藕粉复合膜对冷鲜猪肉的保鲜

以羧甲基纤维素和藕粉为基材制备的交联羧甲基纤维素-藕粉复合膜,具有良好的阻隔性能、力学性能和阻水性。通过研究该复合膜包装和复合膜液涂抹,并用PE膜包装方式对冷鲜猪肉做保鲜处理,结果表明2种处理方式均能较好地保持冷鲜肉的贮藏品质,延长猪肉的贮藏时间。该膜具有较好的抗氧化作用,采用复合膜液涂抹并用PE膜包装方式比单纯复合膜包装和PE膜包装的保鲜效果更好。     

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.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

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...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

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.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.