响应面优化酶法提取马铃薯皮渣中多酚的工艺

为研究酶法提取马铃薯皮渣多酚的最优工艺,采用单因素试验考察复合酶添加量、酶解时间、酶解pH及浸提剂乙醇浓度对多酚提取量的影响,并运用中心组合设计及响应面优化马铃薯皮渣多酚的最佳工艺参数。结果表明,各提取因素对马铃薯皮渣多酚提取量影响的次序为:浸提剂乙醇浓度酶解pH酶添加量。当复合酶添加量1.4%,酶解时间90 min,酶解pH 6.10,浸提剂乙醇浓度47%时,马铃薯皮渣多酚的提取量可达3.21 mg/g。     

蒲公英雪梨保健饮料加工工艺的研究

以蒲公英、雪梨为主要原料,研制蒲公英雪梨复合保健饮料,并探讨各因素对蒲公英浸提、雪梨汁酶解及饮料调配效果的影响。结果表明,蒲公英的最佳超声浸提条件为超声频率40 kHz,料液比1∶25,提取温度70℃,提取次数2次,提取时间1.5 h;雪梨汁的最佳酶解工艺为酶解时间2.0 h,酶解温度40℃,复合酶添加量0.6%,pH值3.5;饮料最佳调配工艺为雪梨汁添加量20%,冰糖添加量8%,苹果酸添加量0.15%,蒲公英浸提液添加量30%,蜂蜜添加量0.005%,制得的产品风味独特、营养丰富、质量最佳。     

海带多糖酶解辅助提取工艺的响应面优化及其稳定性研究

对海带加工下脚料中多糖的酶解提取工艺和化学稳定性进行研究。在单因素试验基础上，采用响应面法对酶解辅助提取的工艺参数进行优化，得出4种酶解因素对海带加工下脚料中多糖提取量影响顺序依次为：复合酶添加量＞pH ＞酶解时间＞温度。最优工艺条件为：液料比40∶1（mL/g），酶解时间135 min，酶解温度55 ℃，酶解液pH 6.0，复合酶添加量2.0%。在该条件下，制得的海带多糖提取量为149.662 g/kg。化学稳定性试验表明，海带多糖提取物在高温和酸性环境下，具有良好的化学稳定性，对碱性环境稳定性较差，是一种化学稳定性较好的天然活性多糖。     

光皮木瓜渣多酚的提取及其抗氧化活性的研究

利用超声法辅助提取光皮木瓜渣中的多酚,考察了乙醇浓度、料液比、超声时间、提取温度等因素对提取量的影响。通过单因素试验和正交试验确定了光皮木瓜渣多酚提取的适宜工艺条件为:乙醇体积分数55%,料液比1∶17,超声时间40 min,提取温度60℃,在此优化条件下,光皮木瓜渣多酚提取量为9.73%;该类光皮木瓜渣多酚粗提液具有较强的抗氧化活性,是一类具有开发价值的天然抗氧化剂。     

桑籽皮多酚的提取工艺研究

通过单因素试验,分析了不同浸提剂、浸提剂浓度、料液比、浸提时间、浸提温度5个因素对桑籽皮多酚提取量的影响,通过正交试验,确定了桑籽皮多酚的最佳提取条件为:浸提剂(丙酮)体积分数为70%,料液比1∶35,回流温度45℃,回流时间1.5h。在此提取条件下,提取量达到1.332mg/g干籽皮,为桑籽皮多酚的工业化提取提供科学依据。     

石榴渣多酚类物质提取工艺研究

以石榴渣为原料,研究了提取溶剂及其浓度、浸提温度、浸提时间和料液比对多酚提取效果的影响,并通过正交试验对4因素影响下的提取工艺进行了优化,确定了石榴渣多酚乙醇提取的最优工艺为:乙醇体积分数50%,浸提温度60℃,料液比1:20,浸提时间4h,以此优化工艺进行试验,一次提取得率为0.51%,二次提取得率为0.69%。超声波辅助提取的最佳处理时间为30min,提取2次,多酚得率为0.79%。原料干燥方式采用烘箱干燥较好。该工艺具有一定的实用性和可行性。     

酶解组合高速匀浆法提取人参总皂苷和多糖

以人参总皂苷和多糖提取得率为考察指标,采用酶解组合高速匀浆法同时提取人参中的两种重要成分,比较不同酶及组合对两者得率的影响,筛选出提取效果较好的果胶酶。通过单因素试验对酶解温度、酶解时间、酶解pH、酶添加量和人参粉末粒径分别进行优化,继而进行响应面试验,得到最佳酶解工艺为:酶解温度60℃,酶解pH 4.7,酶解时间4 h,酶添加量6%,人参粉末粒径约285μm,此时人参总皂苷得率为6.88%,多糖得率为28.58%。将提取后的渣料进行高速匀浆提取,以乙醇浓度、匀浆时间、固液比为变量设计正交试验,得到最佳提取条件为:乙醇浓度0%(蒸馏水),匀浆时间4 min,固液比1∶50(g/mL),此条件下人参总皂苷得率为2.56%,多糖得率为16.92%。两步提取法人参总皂苷得率9.44%,多糖得率45.50%,均高于现有方法的提取得率。     

超声波辅助复合酶法提取苹果多酚工艺优化

为获得超声波辅助复合酶提取苹果多酚的最佳工艺,在单因素试验的基础上,采用正交设计,以多酚得率为评价指标,对工艺条件进行优化。结果表明,最适合苹果多酚提取的复合酶为纤维素酶和果胶酶(质量比1∶1),添加量0.07%,酶解时间60 min,提取温度65℃,超声时间10 min,在此工艺条件下多酚得率为1.99 mg·g~(-1)。     

欧李叶片中多酚的提取工艺优化

【研究目的】以欧李叶片为试验材料,多酚提取率为评价指标,探讨欧李叶片多酚提取的工艺条件。【方法】以丙酮为提取剂,选定浸提时间、溶剂浓度、料液比、浸提温度为考察的4个因素,以L9（34）正交试验设计,采用常规提取法和微波提取法研究提取欧李叶片中多酚的最佳条件。【结果】利用常规法从欧李叶片中提取多酚各因素对多酚提取率影响的主次顺序为：浸提温度＞浸提时间＞固液比＞提取剂浓度,得出最优方案为A1B3C3D3,与试验中最佳处理组合A1B3C3D3相一致;利用微波法从欧李叶片中提取多酚各因素对提取率影响的主次顺序为：提取剂浓度＞固液比＞辐射时间＞辐射功率,得出最优方案为A1B2C3D2,与试验中最佳处理组合A1B2C2D2不一致。【结论】欧李叶片中多酚提取的最佳工艺为70%丙酮溶液,固液比1︰450,浸提时间1.5 h,浸提温度70℃。     

菠萝皮渣多糖的酶法制备及体外抗氧化活性研究

以干菠萝皮渣为原料,采用木瓜蛋白酶法提取菠萝皮渣中的多糖,通过单因素试验和响应曲面试验,确定最优的提取工艺为木瓜蛋白酶添加量1.29%,料液比1∶16(g∶mL),酶解pH值6.37,酶解时间3.24 h,多糖提取率达到4.89%;所提多糖具有清除羟自由基的能力。     

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.     

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.     

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.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding barriers between the cultivated strawberry, Fragaria × ananassa, and related wild germplasm

Five-hundred interspecific and intergeneric crosses were performed among accessions of the wild strawberries Fragaria vesca(2x), Duchesnea indica (8x), Potentilla tucumanensis (2x) and 9 genotypes of the cultivated strawberry, Fragaria×ananassa (8x), following an incomplete diallele mating design. Crosses between D. indica and F.×ananassa produced many putative hybrids when D. indica was used as female but a few achenes and plants when used as male; therefore, pollen-pistil compatibility relations were analyzed by fluorescence microscopy in this direction of the cross. Of the genotypic combinations, 78.6% were incompatible at the stigma level and 17.2% at the first third of the style. Only 3.6% were pollen-pistil compatible and produced fruits with achenes (seven did not germinate or originated short-lived plants and nine produced normal plants). F.vesca×F.×ananassa crosses produced 35 hybrid achenes but only 14% germinated, yielding short-lived plants; histological analyses revealed that inviable seeds had less developed (or collapsed) endosperms and smaller embryos than control plump F. vesca seeds. P.tucumanensis was only used as male, with negative results. These species and genera are partially isolated by a complex system of pre- and post-zygotic barriers. Knowledge of their nature would allow the breeder to devise strategies to put the genetic variability available in the group into a useful form. This revised version was published online in July 2006 with corrections to the Cover Date.