Phytochemical composition of onion during long-term storage

Onion cultivar “Sunpower” has growing popularity in Korea due to high storability. The present study considers changes in flavonols, sugars, and two amino acids in onion bulbs during a long-term storage in the ambient dark storage room and in glasshouse equipped with a climate control system. Flavonol and sugar contents were found to fluctuate noticeably during the storage period. Amino acid content remained relatively unchanged till the onset of inner sprouting, increasing afterward. Visible sprouts appeared at week 22 in the dark storage room and for four weeks later in the glasshouse. The bulbs lost 20–30% of their weight depending on storage conditions at the end of the storage trials. At the same time, the content of nutraceutics in study expressed on the dry weight basis remained of the same order of magnitude. The nature of observed variations in chemical composition of onions as well as relation of this phenomenon to physiological development of stored onion bulbs is discussed. A conclusion is made that the “Sunpower” onion cannot sustain overwinter storage.     

Negative Turgor Pressures in Plant Cells

Non-osmotic moisture stress can be simulated by applying to a plant tissue a solute that cannot penetrate the cell wall. The external reduction in water potential caused by such a non-penetrating solute is compensated for by a reduction in pressure within the cell. The pressure is ambient throughout a cell that has been plasmolysed by a penetrating osmoticum. A supplementary non-penetrating osmoticum must also be compensated for by lowering the internal pressure, i.e. a negative turgor pressure must develop. Onion skin cells can withstand a resulting mechanical stress of up to about 10KPa (1/10 Bar) before collapsing.     

Structural carbohydrate differences and potential source of dietary fiber of onion (Allium cepa L.) tissues.

Onion tissues of three varieties were evaluated for dietary fiber (DF) composition. Insoluble (IDF) and soluble (SDF) dietary fibers were subjected to acid hydrolysis, and the resultant neutral sugars, uronic acids, and Klason lignin were quantified. Brown skin exhibited the highest total dietary fiber (TDF) content (65.8%) on a dry matter basis, followed by top (48.5%) and bottom (38.6%), IDF being the main fraction found. The SDF:IDF ratio decreased from inner to outer tissues. Brown skin and outer leaves byproducts appear to be the most suitable sources of DF that might be used in food product supplementation. The chemical composition reveals that cellulose and pectic polysaccharides were the main components of onion DF in all tissues, although differences between them were noticed. An increase in the uronic acids/neutral sugars ratio from inner to outer tissues was found, suggesting that the galactan side chain shows a DF solubilization role.     

Can the sample variance estimator be improved by using a covariate?

Variance componentsare quantities of central interest in many applications, e.g., in cultivar yield stability analysis and in the analysis of measurement errors. In some applications, the feasible sample size is rather limited, leading to estimates of variance components that are subject to considerable sampling variation. For example, new crop cultivars are tested in only a few environments before release to the market, so the sample size for the variance across environments is small. Similarly, testing a new measurement instrument for some chemical compound may be costly, allowing only a limited number of replications. This article investigates the potential for improving the usual sample variance estimator by exploiting covariate information. In a cultivartrial, yield data may be available for only a few environments while meteorological data or data on a standard cultivar has been recorded for a very large number of environments. Likewise, in the analysis of measurement errors, there may be long-term data on a standard measurement procedure that can be used as a covariate to improve the variance estimate for a new instrument. It is shown in this article that the gain in accuracy achieved by using a covariate can be considerable, provided there is sufficient correlation between the covariate and the variable of interest.     

Photoprotective potential of strawberry (Fragaria × ananassa) extract against UV-A irradiation damage on human fibroblasts

Exposure to UV-A radiation is known to induce discrete lesions in DNA and the generation of free radicals that lead to a wide array of skin diseases. Strawberry (Fragaria × ananassa) contains several polyphenols with strong antioxidant and anti-inflammatory activities. Because the major representative components of strawberry are anthocyanins, these may significantly contribute to its properties. To test this hypothesis, methanolic extracts from the Sveva cultivar were analyzed for anthocyanin content and for their ability to protect human dermal fibroblasts against UV-A radiation, as assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide and Comet assays. Five anthocyanin pigments were identified using high-performance liquid chromatography-diode array detection-electrospray ionization/mass spectrometry. Moreover, the strawberry extract showed a photoprotective activity in fibroblasts exposed to UV-A radiation, increasing cellular viability, and diminishing DNA damage, as compared to control cells. Overall, our data show that strawberry contains compounds that confer photoprotective activity in human cell lines and may protect skin against the adverse effects of UV-A radiation.     

Onions: a source of unique dietary flavonoids

Onion bulbs (Allium cepa L.) are among the richest sources of dietary flavonoids and contribute to a large extent to the overall intake of flavonoids. This review includes a compilation of the existing qualitative and quantitative information about flavonoids reported to occur in onion bulbs, including NMR spectroscopic evidence used for structural characterization. In addition, a summary is given to index onion cultivars according to their content of flavonoids measured as quercetin. Only compounds belonging to the flavonols, the anthocyanins, and the dihydroflavonols have been reported to occur in onion bulbs. Yellow onions contain 270-1187 mg of flavonols per kilogram of fresh weight (FW), whereas red onions contain 415-1917 mg of flavonols per kilogram of FW. Flavonols are the predominant pigments of onions. At least 25 different flavonols have been characterized, and quercetin derivatives are the most important ones in all onion cultivars. Their glycosyl moieties are almost exclusively glucose, which is mainly attached to the 4', 3, and/or 7-positions of the aglycones. Quercetin 4'-glucoside and quercetin 3,4'-diglucoside are in most cases reported as the main flavonols in recent literature. Analogous derivatives of kaempferol and isorhamnetin have been identified as minor pigments. Recent reports indicate that the outer dry layers of onion bulbs contain oligomeric structures of quercetin in addition to condensation products of quercetin and protocatechuic acid. The anthocyanins of red onions are mainly cyanidin glucosides acylated with malonic acid or nonacylated. Some of these pigments facilitate unique structural features like 4'-glycosylation and unusual substitution patterns of sugar moieties. Altogether at least 25 different anthocyanins have been reported from red onions, including two novel 5-carboxypyranocyanidin-derivatives. The quantitative content of anthocyanins in some red onion cultivars has been reported to be approximately 10% of the total flavonoid content or 39-240 mg kg (-1) FW. The dihydroflavonol taxifolin and its 3-, 7-, and 4'-glucosides have been identified in onions. Although the structural diversity of dihydroflavonols characterized from onions is restricted compared with the wide structural assortment of flavonols and anthocyanins identified, they may occur at high concentrations in some cultivars. From bulbs of the cultivar "Tropea", 5.9 mg of taxifolin 7-glucoside and 98.1 mg of taxifolin have been isolated per kilogram of FW.     

Short-term effects of defoliation on the soil microbial community associated with two contrasting Lolium perenne cultivars

Intra-species variation in response to defoliation and soil amendment has been largely neglected in terms of the soil microbial community (SMC). The influence of defoliation and soil fertiliser amendment on the structure of the SMC was assessed with two Lolium perenne cultivars contrasting in ability to accumulate storage reserves. Plant response to defoliation was cultivar specific and depended on the nutrient amendment of the soil. Results suggested a greater ability to alter plant biomass allocation in the low carbohydrate accumulating cultivar (S23) compared to the high carbohydrate cultivar (AberDove) when grown in improved (IMP), but not in unimproved (UNI), soil. Although differences in plant growth parameters were evident, no treatment effects were detected in the size of the active microbial biomass (total phospholipid fatty acid (PLFA) 313.8 nmol g⁻¹ soil±33.9) or proportions of PLFA signature groups. A lower average well colour development (AWCD) of Biolog sole carbon source utilisation profiles (SCSUPs) in defoliated (D) compared to non-defoliated (ND) treatments may be indicative of lower root exudation 1 week following defoliation, as a consequence of lower root non-structural carbohydrate (NSC) concentrations. Within the bacterial community the lower cyclopropyl-to-precursor ratio of PLFAs, and the trans/cis ratio of 16:1w7, in UNI relative to IMP soil treatments indicates lower physiological stress in UNI soils regardless of L. perenne cultivar. Discrimination of broad scale SMC structure, measured by PLFA analysis, revealed that soil treatment interacted strongly with cultivar and defoliation. In IMP soils the SMCs discriminated between cultivars while defoliation had little effect. Conversely, in UNI soils defoliation caused a common shift in the SMC associated with both cultivars, causing convergence of overall community structure. Separation of SMC structure along the primary canonical axis correlated most strongly (P<0.001) with root:shoot ratio (47.6%), confirming that differences in cultivar C-partitioning between treatments were influential in defining the rhizosphere microbial community.     

Fruit maturity and juice extraction influences ellagic acid derivatives and other antioxidant polyphenolics in muscadine grapes

Polyphenolic compounds including ellagic acid, ellagic acid derivatives, and anthocyanins were characterized and quantified by novel chromatographic conditions in eight muscadine grape (Vitis rotundifolia) cultivars and evaluated for antioxidant capacity as influenced by two ripening stages and their location within the fruit (skin, pulp, and juice). All polyphenolics generally increased as fruit ripened and the highest concentrations were located in the skins. Free ellagic acid, ellagic acid glycosides, and total ellagic acid ranged from 8 to 162, 7 to 115, and 587 to 1900 mg/kg, respectively, in the skin of ripe grapes. Hot-pressed juices contained considerably lower polyphenolic concentrations than were present in whole grapes. Five anthocyanidins were present in each cultivar in variable concentrations (delphinidin > petunidin > malvidin + peonidin > cyanidin). Antioxidant capacity was appreciably influenced by cultivar, maturity, and location in the fruit with good correlations to soluble phenolics found in both methanolic and ethyl acetate extracts (r = 0.83 and 0.92, respectively).     

Apple peels, from seven cultivars, have lipase-inhibitory activity and contain numerous ursenoic acids as identified by LC-ESI-QTOF-HRMS

Apple peel contains numerous phytochemicals, many of which show bioactivity. This study investigated the identity of triterpenoid compounds contained in ethanolic extracts of peel from seven apple cultivars. Using HPLC-ESI-QTOF-HRMS, accurate mass information was obtained for 43 compounds, and chemical identity was inferred from the calculated elemental composition, fragment masses, ms/ms, and a limited set of authentic standards. Compounds were identified as triterpene acids and tentatively identified as ursenoic (or oleanoic) acid derivatives containing hydroxyl, oxo, and coumaroyloxy groups. These apple skin extracts exhibited lipase-inhibitory activity, which may be linked to the ursenoic acid content. Furthermore, both triterpene content and lipase-inhibitory activity varied by cultivar.     

不同氮效率水稻品种增硝营养下根系生长的响应特征

试验采用两室分根盒和溶液培养方法,研究了在增硝营养下不同氮效率水稻品种根系生长的响应特征。结果表明,在本试验条件下,与全铵培养下的根系相比,氮高效水稻品种南光在铵硝混合培养下的根系干重和氮积累量显著增加,增幅达33%和41%;同时其根系表面积、根系体积和侧根数增幅均达到显著水平,但根系长度却无明显增加。氮低效水稻品种Elio在铵硝混合培养下的根系生长差异均不显著。这表明氮高效水稻品种南光的根系生长对增硝营养的响应度强,进而促进了根系对氮素的吸收利用。从本试验的结果可推论,水稻对增硝营养的强响应度可能是水稻氮素高效吸收利用的生理机制之一。     

Fruit quality of Redhaven and Royal Glory peach cultivars on seven different rootstocks

Two peach cultivars, Redhaven and Royal Glory, grafted on seven different rootstocks (Adesoto, Barrier 1, GF 677, Ishtara, Monegro, Penta, and peach seedling) were analyzed for tree vigor and yield. Fruit of similar ripeness (fruit firmness) was analyzed in terms of pomological (fruit weight, soluble solids content) and biochemical parameters (individual sugars, organic acids, phenolic acids in the flesh and peel, as well as flavonols and anthocyanins in the peel). A uniform effect of rootstock on tree size was evident in the cases of both cultivars. The Ishtara rootstock induced weak tree growth; Adesoto, Penta and peach seedling semivigorous growth; and Barrier 1, GF 677, and Monegro vigorous tree growth. We recorded higher yields in the Redhaven cultivar, while no significant differences in yield in the fourth growing season were found among the rootstocks for each cultivar. Rootstock had no effect on soluble solids in the Redhaven cultivar, while in the Royal Glory it did. Penta yielded the highest soluble solids content levels, while Adesoto and Monegro were associated with low levels. In the fruit from both cultivars, the rootstock had a significant influence on individual sugars, organic acids, and phenolic acids in the pulp. We also found that phenolic acids in the pulp and skin were more affected by the rootstock than other secondary metabolites analyzed, regardless of the cultivar.     

Hybrids between wild and cultivated carrots in Danish carrotfields

It is well known that wild carrots may pollute the seed cropsof cultivated carrots, but whether cultivated carrots can alsodisperse pollen and seed, and thereby introduce genes into wildcarrot populations, is only little described. In Denmark, there is nocommercial seed production of carrots, and as biennials they shouldnormally not flower before harvest of the roots. Still, floweringindividuals can be found in most Danish fields, and sometimes in veryhigh numbers. At least 75% of the flowering plants are malefertile, with ca. 83% of the pollen being viable. More thanhalf of the plants produce seeds. Pollen and seed dispersal fromfields into wild carrot populations is probably rather frequent inDenmark. A closer inspection of the morphology of flowering plantsindicate that some of these (2–60%) arebolters of pure cultivar origin, as indicated primarily by orangeroot colour. The remainder is probably first or advanced generationhybrids between wild and cultivated plants, as indicated by theirwhite roots and combinations of morphological characters from eitherplant type. Some of these hybrids are imported to Denmark togetherwith the sowing seed, as indicated by significantly differentfrequencies of bolters with white roots in different carrot cultivarstested in the field.     

Comparison of volatile compounds isolated from the skin and flesh of four potato cultivars after baking

Four potato cultivars, Cara, Nadine, Fianna, and Marfona, were selected. Potatoes were baked in their skins prior to separating the skin and flesh and preparing extracts of the volatile flavor compounds using a modified Likens--Nickerson apparatus. The concentrated extracts were analyzed by gas chromatography--mass spectrometry. Volatiles were identified and classified according to their origin, that is, lipid, sugar degradation and/or Maillard reaction not involving sulfur amino acids, sulfur compounds, methoxypyrazines, and other compounds. Quantitative and qualitative differences were observed between isolates from flesh and skins and among cultivars grown at different sites. Strongest isolates from skin were obtained for Nadine. For flesh, Cara gave isolates approximately 10-fold more concentrated than the other three cultivars. For skin, sugar degradation and/or the Maillard reaction was by far the most important source in all cultivars except Nadine, for which 62% of the volatiles were accounted for by the sesquiterpene solavetivone. Lipid and sugar degradation and/or the Maillard reaction were the main origins of volatiles in flesh. Calculated aroma values for a selection of the key potato volatiles identified reinforce the effects of cultivar and growing site on baked potato flavor.     

Composition of transgenic soybean seeds with higher γ-linolenic acid content is equivalent to that of conventional control

γ-Linolenic acid (GLA) has been used as a general nutraceutical for pharmacologic applications, particularly in the treatment of skin conditions such as eczema. Four transgenic soybean lines that produce GLA at high yields (4.21% of total fatty acids, up to 1002-fold) were generated through the stable insertion of the Delta-6-fatty acid desaturase gene isolated from Borago officinalis into the genome of a conventional soybean cultivar. As part of the safety assessment of genetically engineered crops, the transgenic soybean seeds were compared with their parental soybean seeds (nontransgenic) by applying the principle of substantial equivalence. Compositional analyses were conducted by measuring the fatty acids, proximate analysis (moisture, crude protein, crude fat, carbohydrates, TDF, and ash contents), amino acids, lectins, and trypsin inhibitor activity. The present results showed that the specific transgenic cultivar studied was similar to the conventional control.     

Morphological biodiversity and local use of the Himalayan pear (<Emphasis Type="Italic">Pyrus pashia</Emphasis>) in Central Bhutan

A survey was undertaken in two valleys of the Bumthang area in Central Bhutan to study the morphological diversity, farmers’ knowledge, management practices, yield and income generation potential of the neglected Himalayan Pear (Pyrus pashia Hamilton ex D. Don). For this study a total of 148 Pyrus pashia accessions were collected and 103 households interviewed. Three quantitative and 14 qualitative traits such as colour, size, shape and texture of fruits and tree habit were used for morphological characterization of the accessions. The results demonstrated a high morphological diversity within the P. pashia trees. Fruit shape varied widely from globose to pyriform, fruit skin colour from light yellow and glossy to brown and dull. The observed diversity is likely due to the fact that under farmers’ conditions trees are propagated through seedlings rather than by grafting. None of the characters were specific and correlated with region or altitude. Distinct local cultivars with specific characters were absent making it impossible to group the pears morphologically. Interviews revealed low numbers of trees per farmers, lacking marketability of the fruits and farmers’ subsequent preference for improved varieties as major obstacles for the in situ preservation of biodiversity in P. pashia in this area.     

Effect of genotype and storage time on stability of colour,phenolic compounds and ascorbic acid in red raspberry (Rubus idaeus L.) jams

Changes in colour, phenolic composition and ascorbic acid (AA) concentrations in jams made from eight, floricane fruiting, red raspberry genotypes stored for six months at 20°C were investigated. Additionally, the relationship between genotypes and quality parameters was assessed. On average for all genotypes, 83% AA degradation was observed during the first three months of storage. After six months, the concentrations of anthocyanins, total quercetin glycosides and lambertianin C decreased by 80%, 13% and 7%, while ellagic acid conjugates and total phenolics increased by 47% and 8%, respectively. The anthocyanins detected in highest concentrations in fresh jams, that is, cyanidin-3-(2^g-glucosylrutinoside), cyanidin-3-sophoroside, cyanidin-3-glucoside and cyanidin-3-rutinoside showed the highest stability during storage, that is, 28%, 21%, 12% and 11% left after six months of storage, respectively. A significant decrease in colour (lightness, chroma and hue) was also observed during storage. The colour changes of stored jams, however, were much slower than the pigment degradation. On average, lightness, chroma and hue decreased by 13%, 29% and 18% during six months of storage, respectively. The lowest anthocyanin degradation was observed in jams characterised by red-bluish colour and high initial anthocyanin content, that is, ‘Veten’, ‘RU024 01003’ and ‘RU974 07002’ with 72–78% degradation after storage for six months, while the highest losses (82–93%) were observed in jams characterised by saturated red-orange colour, high ellagitanin and low initial anthocyanin contents, that is, ‘Glen Magna’, ‘Malling Hestia’ and ‘Octavia’. The results indicate that the genotypes ‘RU024 01003’ and ‘RU974 07002’ might have the potential to replace ‘Veten’, the main cultivar for jam processing in Norway, as new cultivars for industrial processing provided good cultivation qualities and satisfactory taste and flavour of the products.     

Soil colour: its measurement and its designation in models of uniform colour space

The principles of colour perception are outlined and applied to the problems of soil colour measurement using ‘Munsell Soil Color Charts’. As care is needed in using these charts to make an accurate assessment of soil colour, recommendations for the correct methods for soil colour measurement are outlined. The three soil colour characteristics of Munsell Hue, Value and Chroma are commonly used in multivariate analyses as orthogonal, equi-dimensional, linear variables that describe perceived colour space. Such an approach may be inappropriate because the angular separation of Hue and an approximately 2.5:1 scaling relationship between Value and Chroma should be accounted for in any model of perceived colour space. An appropriate and simple polar transformation of Munsell colour data is compared with some other coordinate systems for representing colour space, including the CIELAB system. This polar transformation is recommended for processing colour data in multivariate analyses.     

Molecular characterization of short-day onion genotypes by intron length polymorphic (ILP) markers

Genetic Resources and Crop Evolution - Onion (Allium cepa L.) is an economically important vegetable that is in high demand around the world. It is a highly cross pollinated crop, which could...     

3种大蒜中洋葱黄矮病毒的RT-PCR分子鉴定

洋葱黄矮病毒（Onion yellow dwarf virus,OYDV）是危害大蒜产量和品质的主要病毒之一。快速有效的病毒检测方法可为大蒜病毒病的研究和有效防御提供理论与技术资料。本研究利用反转录-聚合酶链式反应（RT-PCR）技术对甘肃＂成县迟蒜＂和山东＂鲁蒜王2号＂中OYDV外壳蛋白基因进行特异性扩增,并克隆到载体PMD18-TEasy Vector上进行核苷酸序列测定及分析。成功分离得到OYDV的两个DNA片段——GSCCS和SDLSW2,与GenBank中已报道的AB000837.1、AB000838.1和AJ409311.1等22个OYDV DNA片段的核苷酸相似性分别为81%～98%和81%～84%,氨基酸相似性分别为85%～99%和89%～94%,二者之间核苷酸相似性为84%,氨基酸相似性为89%。系统进化树显示不同DNA片段可聚为3个组群,GSCCS与中国山东金乡OYDV DNA片段同属一组,SDLSW2与其它16个OYDV DNA片段同属一组,表明OYDV在甘肃＂成县迟蒜＂和山东＂鲁蒜王2号＂中均存在,但具有一定差异。本实验确定了OYDV的基因变异程度,为进一步研究病毒进化和变异提供了有利条件。     

Primary and secondary metabolite composition of kernels from three cultivars of Portuguese chestnut (Castanea sativa Mill.) at different stages of industrial transformation

Chestnut (Castanea sativa) is an important basic food in rural diets and a major starch crop used in a similar way to potatoes. Chestnuts are a fundamental economic resource in the "chestnut regions" not only for the fruit but also for the chestnut wood. Chestnuts have become increasingly important with respect to human health, for example, as an alternative gluten-free flour source. Chestnuts are also a rich source of other beneficial compounds, but there have been few studies on the composition during processing. In this study, we analyzed the chemical composition of three Portuguese cultivars at different stages of industrial processing. The chestnut cultivars were Longal, Judia, and Martaínha. All three cultivars had high moisture contents but were low in ash, crude fat, and crude protein contents, with high starch and low fiber contents. The free amino acid contents, including various essential amino acids, varied depending on the cultivar. All three cultivars also had a significant content of polyphenolics with gallic acid; ellagic acid was predominant among hydrolyzable and condensed tannins. Many of these compounds are known to exert significant positive effects on human health. The one-way analysis of variance for fresh chestnut shows significant differences among the three cultivars for most of the studied parameters. The same statistical analysis applied to each one of the two cultivars (Judia and Longal) sampled for the four processing steps analyzed indicates a significant effect of this factor in practically all of the constituents. On the other hand, the two-way analysis of variance shows that, besides the residual, the processing step and the interaction cultivar x processing step were the factors that more contributed for the total variation observed in the constituents analyzed, while the contribution of cultivar was much less significant.