红叶甜菜红色素的稳定性研究

采用80% 乙醇为提取溶剂,将提取的色素液在230～700nm 范围内进行紫外扫描,而后分别探讨碳水化合物、pH 值、温度、氧化剂还原剂、光照、金属离子对色素在紫外和可见光区的稳定性的影响。结果表明：该色素在紫外光区有两个吸收峰,波长分别为270、334nm,可见光区有两个吸收峰,波长分别为538、666nm;红叶甜菜红色素对热比较稳定,但不耐高温;pH 值对色素颜色影响不是很大,除pH10 以外;碳水化合物对其影响不显著;其抗氧化能化较弱;自然光照射一定时间会褪色;大多数金属离子对其无影响;而Fe3+ 等少数金属离子对色素有影响。     

Responses of Sugar Beet (Beta vulgaris) to Foliar Sprays of Copper

Previous studies have shown positive yield responses from foliar copper (Cu) applications to beet. However, some of these responses may have been due to fungicidal instead of nutritional effects. Also, since these studies, national yields have increased possibly increasing the Cu requirement of the beet crop. So, between 1987 and 1990 six field experiments tested the effect of foliar sprays of copper on the yield and processing quality of sugar beet. The copper was applied as Cu oxychloride or an inorganic Cu formulation, in factorial combination with a wetter or an adjuvant. Four of the experiments were on loamy sand textured soils, the remainder on peaty soils. The Cu sprays did not affect beet yields for crops grown on the peat soils. On two of the light textured mineral soils the Cu sprays did increase yield, but there was no clear relationship between soil ethylene diamine tetra acetic acid (EDTA) extractable Cu and yield response to added Cu. There was little difference between the forms of Cu tested on yield, or between the wetter or the adjuvant. Cu sprays did not affect beet processing quality, even when large yield responses were obtained. An analysis of the geographical distribution of sugar beet quota and soil extractable Cu showed that 15% of the UK's national crop could be affected by Cu deficiency.     

HPLC‐MSn Identification of Betalain Profile of Different Beetroot (Beta vulgaris L. ssp. vulgaris) Parts and Cultivars

The distribution of betalains in peel, flesh, and petioles of yellow and red beetroot cultivars has been investigated using an High‐performance liquid chromatography (HPLC) system with electrospray mass spectrometry. Differences in the levels of betacyanins and betaxanthins between different colored cultivars were individually determined for 3 plant parts. The content of almost all analyzed compounds decreased in the following order: peel > flesh > petiole. Betanin/isobetanin pigments comprised a major portion of the relative peak area measured in red beetroot peel. Isobetanin relative peak areas were also high in leaf petioles (68.94% to 74.16%) of red colored cultivars. However, betacyanins were completely absent from the extracts of all analyzed parts of yellow beet. Glutamine‐bx represented a very high relative peak area (59.54% to 64.18%) in flesh of red‐colored cultivars analyzed in the study. Our results indicate that red beet cultivars can be utilized as a potential source of red and yellow natural colorants. However, differences in pigment composition among different beetroot parts must be considered and in order to maximize the pigment yields petioles can also be used as a source rich in specific betalain compounds.     

Production of Isoamyl Acetate from Sugar Beet Molasses by Williopsis saturnus var. saturnus

Three strains of Williopsis saturnus var. saturnus were employed for the production of natural isoamyl acetate (the character impact compound of banana flavour) using sugar beet molasses as the carbon source and batch cultivation at 25°C under anaerobic conditions. Of the three strains, strain HUT 7087 was the best producer of isoamyl acetate, producing 20.7 mg/L. Sugar beet molasses was deemed to be an acceptable carbon source for the production of this flavour compound.     

Isolation and Characterization of Hemicellulose and Cellulose from Sugar Beet Pulp

Various conditions for the extraction of hemicellulose and cellulose from sugar beet pulp were examined, including pulp particle size, temperature of EDTA extraction, temperature and concentration of alkaline extraction, and delignification time. A procedure using 60 mesh pulp, 85°C EDTA extraction of pectins, 10% NaOH extraction at 25°C followed by one hour delignification gave the highest yields. Molecular weights of hemicellulose ranged from 40,000 to 150,000 daltons for the A form and 10,000 to 150,000 daltons for the B form. The monosaccharide composition of hemicellulose A and B differed significantly. Hemicellulose B had the highest water-holding capacity followed by hemicellulose A and cellulose. Viscosity of the hemicelluloses was very low.     

Betalain and Phenolic Compositions,Antioxidant Activity of Tunisian Red Beet (Beta vulgaris L. conditiva) Roots and Stems Extracts

In the present study, betalains content, phenolic composition, and antioxidant activity of different parts of red beet (Beta vulgaris L. conditiva) (i.e., roots and stems) were compared. Crude extract of root showed the highest betalain content with a maximum of 53 ± 4 mg betanin eq and 46 ± 3 mg vulgaxantin I eq g^?1 of extract stems showed higher total phenolic concentration than roots, ranging between 2.0 ± 0.4 and 14.6 ± 0.5 mg gallic acid eq^?1 of extract. Chemical composition was analyzed using LC-MS. Betalains (vulgaxanthin I, betanin, and isobetanin) and phenolics (gallic acid, ferulic acid, chlorogenic acid, caffeic acid, vanillic acid, syringic acid, ellagic acid myricetin, quercetin, rutin, kampferol) were identified in roots and stems. Betalain extract obtained from roots showed higher antioxidant activity than extract obtained from stems.     

TaqMan探针荧光定量PCR检测甜菜低温胁迫相关miRNAs

本项研究根据模式植物拟南芥中miR156,157,159,167,319,396在植物中所具有的广泛同源性及其在非生物胁迫环境下可能具有的共同调控机制,采用TaqMan探针实时荧光定量PCR技术检测低温胁迫下甜菜幼苗同源miRNAs的差异表达,以期揭示甜菜响应低温胁迫的可能分子机制.实验表明,甜菜中存在与拟南芥同源的miR156,157,159,167,319,396基因,miR159基因表达稳定,在本实验中用作定量内参,miR156,157,167,396明显下调,而miR319虽然被认为与miR159属于同一家族,但在甜菜幼苗低温胁迫下表现为明显上调,说明miR156,157,167,319,396是甜菜中响应低温信号的调控分子.本研究首次识别甜菜中存在与拟南芥同源的6个miRNAs,为进一步探索甜菜响应低温胁迫的分子机理奠定了技术.     

气相色谱-质谱法分析籽瓜中的化学成分

采用索氏提取法提取籽瓜籽中的脂肪酸,用气相色谱- 质谱联用仪(GC-MS)进行分析,分离鉴定出10 种脂肪酸,其主要化学成分为亚油酸、棕榈酸和硬脂酸。用同时蒸馏- 萃取法提取籽瓜皮中的挥发性物质,用气相色谱- 质谱法从籽瓜皮的挥发油中分离并鉴定出30 种化学成分。     

Impact of Thermal Treatment on Color and Pigment Pattern of Red Beet (Beta vulgaris L.) Preparations

ABSTRACT: The impact of heating at 85°C during 8 h on overall color and betalain pattern of red beet ( Beta vulgaris L. ssp. vulgaris ) juice was investigated. Although the hue angle of 358° in fresh juice was indicative of the typical red-purple appearance, heating for 8 h induced an unexpected shift to 62° resulting in a yellow-orange solution. To monitor the underlying structural alterations of betalains, a new high-performance liquid chromatography separation compatible with mass spectrometry was developed. Applying this method, 2 novel yellow neobetanin structures and 2 orange-red betanin degradation products were preliminarily identified, and neobetanin formation resulting from heat exposure was proven for the 1st time. These 5 compounds were held responsible for the orange shift of red beet juice during thermal treatment. The relevance of these findings for industrial beet processing was demonstrated by comparison of pigment patterns of heated red beet juice samples and a commercial concentrate. On the basis of these results, a scheme for the thermal degradation of betanin is proposed.     

Extraction and Charcterization of Pectins from Sugar Beet Pulp

Conditions (pH, temperature, time) for the extraction of sugar beet pulp pectins were studied on a laboratory scale and transposed into a pilot plant. Good yields (～ 14%) of pectins are obtained if the pulp is treated at pH 1.0, 85°C for 1 hr. The characteristics of the pilot extracted pectins are very close to those of the laboratory ones, except for a lower molecular weight (～30,000 daltons). Their physicochemical properties confirm their poor gelling ability.     

The effect of red beet (Beta vulgaris var. rubra) fiber on alimentary hypercholesterolemia and chemically induced colon carcinogenesis in rats

The effect of diet supplemented with 5% and 15% cellulose or with 15% fiber isolated from red beet (Beta vulgaris var. rubra) on the development of alimentary hypercholesterolemia and chemically induced colon carcinoma was studied in male Wistar rats. Hypercholesterolemia was induced by a diet containing 0.3% of cholesterol and colon carcinoma was induced by treatment with dimethylhydrazine (20 mg/kg, 12 doses applied s.c. in one-week intervals). Fibrous matter isolated from red beet contained 89% fiber, of which 9% was in water soluble form. Animals were killed 14 weeks after the application of dimethylhydrazine (i.e. 26 weeks after starting on the diets). Red beet fiber diet (and not the increased cellulose intake) caused a reduction of serum cholesterol and triacylglycerol levels (by 30 and 40%, respectively) and a significant increase in the fraction of cholesterol carried in HDL. This diet induced also a significant decrease (almost by 30%) of cholesterol content in aorta. Higher cellulose content in the diet and even more so the administration of red beet fiber caused a significant reduction of conjugated dienes content in plasma, erythrocytes and in liver. Also observed were increases in the activities of superoxide dismutase and catalase in erythrocytes and in colon and activities of glutathione peroxidase and glutathione-S-transferase in liver. The presence of both higher cellulose content and red beet fiber in the diet significantly reduced the incidence of precancerous lesions--aberrant crypt foci--in the colon. The diet containing red beet fiber did not affect significantly the incidence of colon tumours although the number of animals bearing tumours was reduced by 30%.     

Phenylacetonitrile; an auxin-like growth substance from sugar beet (Beta vulgaris)

Steam distillates and ethyl acetate extracts of sugar beet leaves and roots contained an auxin-like substance that stimulated elongation of wheat-coleoptile sections, and whose mobility on paper chromatograms was similar to phenylacetonitrile. Gas chromatography-mass spectrometry detected and identified phenylacetonitrile, together with 11 other volatile constituents, from sugar beet leaves.     

Kinetic Properties of Peroxidase Enzyme from Chard (Beta vulgaris Subspecies cicla) Leaves

Peroxidases are heme containing enzymes that are produced by a number of organisms. A plant peroxidase was purified from leaves of chard (Beta vulgaris subspecies cicla) by ammonium sulphate precipitation, dialyses, and CM-sephadex cation exchange chromatography. Purification fold was approximately 36 with 14.4% yield. Optimum pH, optimum temperature, optimum ionic strength, and stable pH values of purified enzyme were determined for the guaiacol substrate. Michaelis constant (K_M) and maximum rate (V_max) values were determined from the Lineweaver–Burk graph for pyrogallol and guaiacol substrates. Phenolic and flavonoid contents in chard that connected with antioxidant properties were determined as 17.5 μg (GAE/mg extract) and 11.7 μg (QE/mg extract), respectively. In conclusion, chard is shown to be a novel rich source of phenolic antioxidants and has a high peroxidase activity.     

The availability of soluble oxalates in stir‐fried silver beet (Beta vulgaris var. cicla) leaves eaten with yoghurt

Silver beet (Beta vulgaris var. cicla) leaves contain oxalates, and the addition of yoghurt, a food rich in calcium, to stir‐fried leaves was investigated as a way of reducing the soluble oxalate content. Fourteen participants ingested 115 g stir‐fried silver beet leaves with or without standard yoghurt and low‐fat yoghurt, respectively. Stir‐fried silver beet leaves contained 209.1 ± 0.1 mg of total oxalates per meal fresh weight (FW) and 109.2 ± 0.1 mg of soluble oxalates per meal FW. The proportion of soluble oxalates was reduced from 52% to a mean of 30% of the total oxalates when standard yoghurt or low‐fat yoghurt was added. The mean absorption of oxalate was determined by measuring the output of oxalate in the urine over a 6‐h period following ingestion of the meals. The mean absorption of oxalate from stir‐fried silver beet leaves was 2.41%, which reduced to 1.10% and 0.89% when consumed with standard yoghurt and low‐fat yoghurt, respectively.     

甜菜废粕中食用纤维的制取

对甜菜废粕制取食用纤维的工艺进行了研究。将压粕和磨碎的干粕分别采用盐酸、氢氧化钠和乙醇处理。结果表明：用95％乙醇处理压粕的工艺最佳，所得的产物干燥、筛分后即为食用纤维，产品无色无味。对产品的主要成分和理化性能作了分析。     

The effect of three organic pre-harvest treatments on Swiss chard (Beta vulgaris L. var. cycla L.) quality

Despite the increasing interest in organic products, our understanding of how different organic treatments affect fruit and vegetable quality is still limited. The effect of three organic pre-harvest treatments [effective microorganisms (EM), a fermented mixture of effective microorganisms with organic matter (EM-Bokashi + EM), and an auxiliary soil product (Greengold^®)] on Swiss chard quality was evaluated. The Swiss chard was analyzed 8 and 19 weeks after sowing. The treatments did not notably modify the physical and chemical quality of the chard when compared with control plants. Chard harvested 19 weeks after sowing showed greater differences in nutritional quality than chard harvested 8 weeks after sowing. Control plants had higher water content than the plants treated with EM, EM-Bokashi + EM and Greengold^®. Chards treated with EM-Bokashi + EM had lower ascorbic acid content and higher phosphor and magnesium content than control plants. Application of EM to plants induced higher levels of calcium compared with non-treated plants.     

Betalain and phenolic compositions of four beetroot (Beta vulgaris) cultivars

Four cultivars of red beetroot (Beta vulgaris) were evaluated with respect to their betalain and phenolic contents. The compounds were analysed using HPLC and identified by HPLC-DAD, HPLC-ESI-MS and NMR techniques. Betalains (vulgaxanthins I and II, betanin and isobetanin) and phenolics [5,5',6,6'-tetrahydroxy-3,3'-biindolyl, feruloylglucose and #-D-fructofuranosyl-!-D-(6-O-(E)-feruloylglucopyranoside)] were determined in different parts of the root; betalains were analysed separately in the water extract and phenolics in the fractionated 80% aqueous methanol extract (betalain-free water fraction). In each cultivar, both betanin and isobetanin were found in greater amounts in the peel than in the flesh. A similar trend was not observed in the distribution of vulgaxanthins. The three studied phenolics appeared in all root parts of the beetroot cultivars with the flesh generally containing the least content. Additionally, two phenolic amides (N-trans-feruloyltyramine and N-trans-feruloylhomovanillylamine) and four flavonoids (betagarin, betavulgarin, cochliophilin A and dihydroisorhamnetin) were detected in the fractionated 80% aqueous methanol peel extracts (acetonitrile fraction) of beetroot.     

Primary structures of proteinase inhibitors fromPhaseolus vulgaris var.nanus (cv. Borlotto)

The primary structures of two trypsin-chymotrypsininhibitors fromPhaseolus vulgaris var.nanus (bush bean, cv. Borlotto), PVI-3₂ und PVI-4, were derived from automated Edman degradation data, amino acid composition and manual Edman degradation results of enzymatic fragments and homology with other Bowman-Birk type proteinase inhibitors. The highest degrees of homology were observed between PVI-3₂ or PVI-4 and the trypsin-chymotrypsin inhibitors from lima beans (LBI I, IV and IV′, 86%), black-eyed peas (BTCI, 81%), and, in part, adzuki beans (ABI I, II and II′, 74–77%). Similarly, the primary structure of the trypsin-elastase inhibitor from the same source, PVI-3₁, was deduced which showed highest homology with that of the trypsin-elastase inhibitor GBI II from garden beans (92%), followed by GBI II′ from garden beans (86%) and C-II from soybeans (71%). In contrast, homology between PVI-3₂ and PVI-4 on the one hand and PVI-3₁ on the other was relatively low (61%).     

Characterization of native microbial populations on Swiss chard (Beta vulgaris,type cicla) cultivated by organic methods

The native microflora of fresh Swiss chard (Beta vulgaris, type cicla) cultivated by organic methods was quantified and characterised. The concentration of the different microorganism groups presented less variability among different lots than results found on chard leaves produced by conventional methods. These results would indicate a greater degree of homogeneity among the different samples of chard produced by organic procedures.The microbial populations on Swiss chard leaves produced by organic methods were 6.8×10⁵ CFU/g for mesophilic microorganisms, 3.9×10³ CFU/g for psycrotrophic microorganisms, 1.4×10⁴ CFU/g for lactic acid microorganisms, 5.1×10³ CFU/g for total coliforms and 1.66×10³ CFU/g for Staphylococcus spp. Neither fecal coliforms nor human pathogens were identified. Immersion of organic Swiss chard leaves in tap water at 18°C for 4 min reduced microbial populations but did not accomplish more than 70% removal in any of the populations under study.