响应面法优化高DE值麦芽糊精制备工艺的研究

研究了耐高温α-淀粉酶水解制备高DE值麦芽糊精的工艺,用响应面法分析了反应时间、反应温度、酶添加量及淀粉乳浓度对DE值的影响,得出制备高DE值麦芽糊精的最优条件为:时间25 min,加酶量48 U/g,温度95℃,底物质量分数为20%,DE值为19%～20%。     

马铃薯淀粉制备脂肪模拟物的工艺研究

以马铃薯淀粉为原料,采用高温α-淀粉酶水解马铃薯淀粉,制备低DE值麦芽糊精脂肪模拟物。通过单因素试验,研究了酶添加量、反应时间、反应温度和底物浓度对产品DE值的影响,并通过正交试验确定了制备工艺的最佳条件为:酶添加量为0.02g,温度为95℃,反应时间为10min,底物质量分数为15%,水解产物的DE值为2.96。     

酶法制备低DE值小米淀粉糖浆的技术研究

为了研究高温α-淀粉酶水解小米淀粉制备低DE值(<20%)淀粉糖浆的工艺,笔者通过单因素试验,明确了温度、时间和酶加入量对水解产物DE值和液化得率的影响,并通过正交试验优化了小米淀粉酶解工艺参数。试验结果表明,当底物浓度为30%时,高温淀粉酶加入量50 U/g淀粉,反应温度为85℃,反应时间30 min,制备的糖浆DE值为16.77%,小米淀粉的液化得率为81.27%。     

辛烯基琥珀酸酶解淀粉酯制备条件的研究

以自制的酶解糯米淀粉为原料，对辛烯基琥珀酸糯米淀粉酯制备过程的pH值、反应温度、反应时间与淀粉乳浓度等影响因素进行了研究，得到单因素的最优工艺条件：反应温度35℃、反应时间12h、pH值8．0、淀粉乳质量分数40％、辛烯基琥珀酸酐用量为3％：     

荞麦饮料酶解工艺研究

未经处理的荞麦饮料具有极不稳定的性质,通过单因素试验和正交试验,利用α-淀粉酶的酶解作用,将淀粉大颗粒降解为可溶性糖,确定荞麦饮料最佳酶解工艺,以提高其稳定性。试验表明,料液比1:8,α-淀粉酶酶解温度65℃,酶添加量0.4%,酶解时间60 min为最佳酶解工艺,各因素对荞麦饮料DE值的影响主次顺序为酶解时间酶添加量酶解温度,对荞麦饮料DE值的影响表现为酶解时间极显著、酶添加量显著、酶解温度不显著。此条件下生产的荞麦饮料香味浓郁、口感好、稳定性较好。     

酶法去除米糠淀粉及其酶解动力学研究

以酶解后米糠中的残留淀粉量为考察指标,研究酶解反应过程中酶添加量、pH值、反应温度和反应时间对酶解效果的影响,在酶的最佳反应条件下测定淀粉酶的动力学常数Km和Vm。实验结果表明,利用α-淀粉酶酶解米糠中的淀粉的最佳工艺条件为酶添加量2.00%、酶解反应pH值为6、酶解反应温度60℃、酶解反应时间1h,酶解后米糠中的淀粉含量由22.65%降至0.43%。在60℃、pH值为6时测定α-淀粉酶水解米糠中的淀粉的动力学常数Km=8.649g/L、Vm=1.249g/L&#183;min。     

不同提取方法对半叶马尾藻多糖提取率的影响研究

应用热水提取法、酶解法、超声波提取法3种方法,从半叶马尾藻中提取多糖,以多糖提取率为指标,通过单因素和正交优化实验分别确立提取多糖的最佳工艺条件。结果表明,热水提取法的最佳工艺为：水浴温度85℃,pH值2．0,水浴时间5h,料液比1：30;酶解提取法的最佳工艺为：酶解温度50℃,时间2．5h,酶用量l％,pH值4．8,料液比1：30;超声波提取法的最佳工艺条件为：超声时间30min,温度80℃,功率300W,pH值2．0,料液比1：30。3种工艺的多糖提取率分别为：热水提取法4．50％,酶解法6．13％,超声波法10．55％。     

木薯交联多孔淀粉制备工艺的研究

研究了制备木薯交联多孔淀粉的工艺模型和最优条件。以交联多孔淀粉吸油率作为考察指标,通过回归正交试验,考察了温度、酶用量、时间、pH值和交联度（沉降积）等主要因素对交联多孔淀粉吸油率的影响。结果表明,吸油率与各试验因素之间的关系可用一次回归方程来描述,回归方程经F检验非常显著;较佳工艺条件为：反应温度50℃,反应时间8h,酶量1％,pH值5．0,酶配比1：5及低交联度（沉降积3．4）,在此条件下所得交联多孔淀粉的吸油率为90％。     

山药抗性糊精的微波预处理-酶解制备及其性质研究

抗性糊精属于水溶性膳食纤维范畴,可以作为益生元添加到食品中。以山药淀粉为原料,通过微波预处理-酶解的方式制备山药抗性糊精,并对其溶解性、热性质、相对分子质量和体外消化性进行分析测定。结果表明,在山药淀粉经过微波功率60 W,微波时间6 min预处理后,再通过添加β-淀粉酶20 U/g,转苷酶35 U/g,在酶解温度75℃的条件下酶解时间20 min,可得到含量为40.33%的山药抗性糊精。该山药抗性糊精分子量约为4 000 Da,具有较好的溶解性和热稳定性,对人造胃液和小肠液具有很强的抗消化性能。该方法制备的山药抗性糊精分子量小、溶解性好、热稳定性高,适用软饮料的配制。     

西番莲粉喷雾干燥工艺研究

采用酶解西番莲汁为原料,以麦芽糊精为助干剂,通过喷雾干燥法制备了西番莲粉,研究麦芽糊精添加量、进风温度、进料流量和进料浓度对西番莲粉产率、VC含量和含水率的影响。在单因素试验的基础上,采用正交试验优化了西番莲粉喷雾干燥工艺参数。结果表明,西番莲粉喷雾干燥的最佳工艺参数为:麦芽糊精添加量60%(按照喷雾干燥前料液总固形物含量计算),进风温度170℃,进料流量9 mL/min,进料浓度30%,此条件下西番莲粉的产率50.47%,VC含量58.88 mg/100 g,含水率4.8%。制得的产品具有西番莲特有的果香,研究为西番莲的产品多样化提供新的方法和思路。     

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.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

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.     

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...     

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.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...