Combined effects of prefermentative skin maceration and oxygen addition of must on color-related phenolics, volatile composition, and sensory characteristics of Airén white wine

The effects of the joint prefermentative maceration and hyperoxygenation of Airén white must and wine on the phenolic content, chromatic characteristics, volatile composition, and sensory characteristics, not previously described in combination, have been evaluated. A total of 20 phenolic and 149 volatile compounds have been identified and quantified for that purpose. As a consequence of the oxygen addition, the concentrations of hydroxycinnamic acid derivatives and flavan-3-ols decreased (above all t-GRP and (+)-catechin), leading to color stabilization, but also the concentrations of several volatile compounds with a great importance for quality aroma decreased. Prefermentative skin maceration, previously applied to the hyperoxygenation of Airén musts, provided the aforementioned color stabilization in the respective wine but also increased the content of short-chain fatty acid esters and terpenes and decreased the concentration of C(6) alcohols. That combination of prefermentative treatments (skin maceration followed by must hyperoxygenation) produced an improvement of the global impression of the final wine based on significantly better scores of tropical fruit, body, and herbaceous notes.     

Effect of chitosan, O-carboxymethyl chitosan, and N-[(2-hydroxy-3-N,N-dimethylhexadecyl ammonium)propyl] chitosan chloride on overweight and insulin resistance in a murine diet-induced obesity

Two water-soluble chitosan derivatives, O-carboxymethyl chitosan (O-CM-chitosan) and N-[(2-hydroxy-3-N,N-dimethylhexadecyl ammonium)propyl] chitosan chloride (N-CQ-chitosan), were prepared, and the therapeutic effects of chitosan, O-CM-chitosan, and N-CQ-chitosan on insulin resistance were simultaneously evaluated by rats fed on a high-fat diet. The parameters of high-fat diet-induced rats indicated that chitosan and its two derivatives not only have low cytotoxicity but can control overnutrition by fat and achieve insulin resistance therapy. However, the results in experiment in vivo showed that the therapeutic degree varied by the molecular weight and surface charge of chitosan, O-CM-chitosan, and N-CQ-chitosan. N-CQ-chitosan with a MW of 5 × 10(4) decreased body weight, the ratio of fat to body weight, triglyceride, fasting plasma glucose, fasting plasma insulin, free fatty acid, and leptin by 11, 17, 44, 46, 44, 87, and 64% and increased fecal lipid by 95%, respectively.     

Separation and HPLC-MS identification of phenolic antioxidants from agricultural residues: almond hulls and grape pomace

Almond hulls and grape pomace are residues abundantly generated by agricultural industries, which could be processed to obtain bioactive products. To this purpose, crude ethanol extracts from both agricultural byproducts were attained and subsequently fractionated in order to obtain an organic/water fraction (FOW). Extracts and fractions were analyzed for antioxidant power and their phenolic components tentatively identified by HPLC-MS. Chromatographic peaks of almond hull extracts showed the occurrence of hydroxybenzoic and cinnamic acid derivatives, with minor presence of flavan-3-ols (ECG, EGCG), whereas the FOW fraction offered the additional presence of epicatechin (EC) and glycosylated flavonols. In the composition for extracts of white and red grape pomace several of these compounds were also detected but basically consisted of glycosylated flavonols (quercetin, kaempferol). As a difference between both grape pomaces, myricetin glycosyde was found in that from the red variety, whereas flavan-3-ols (EC, afzelechin) were only identified in white pomace. When their FOW fractions were analyzed, gallic acid and some hydroxybenzoic acids were additionally detected. Antioxidant activity was assessed by DPPH and TBARS assays. Almond hulls showed inhibition percentages lower than 50% in both assays, while the inhibition percentage ranged from 80% to 90% in pomace extracts. Red grape pomace extract was the most efficient antioxidant, with an EC50 value of 0.91 g/L for TBARS and 0.20 g/L for DPPH. Even appearing as two quite different vegetal matrixes, the composition of phenolics in grape pomace and almond hulls is quite similar, the main difference being the major occurrence of flavonols in grape pomace. This fact could presumably explain the lower antiradical activity of hull extracts.     

辐照甘薯切苗选育新品系

用~(60)Coγ射线辐照甘薯切苗,获得了抗黑斑病的突变系。经多点试验、区域试验和生产试验,突变无性系农大601(12-11-8)的春薯鲜产量和干物质含量均比原品种有所提高,且具有较强的抗黑斑病性能。采用聚丙烯酰胺电泳技术进行酯酶同工酶分析表明,农大601和亲本品种间存在一定差异。根尖细胞观察结果表明:辐照当代有明显的染色体畸变,但到第6无性代时,已和对照一样。因此说明变异不是染色体畸变造成,而是基因突变。     

Weakening of salmonella with selected microbial metabolites of berry-derived phenolic compounds and organic acids

Gram-negative bacteria are important food spoilage and pathogenic bacteria. Their unique outer membrane (OM) provides them with a hydrophilic surface structure, which makes them inherently resistant to many antimicrobial agents, thus hindering their control. However, with permeabilizers, compounds that disintegrate and weaken the OM, Gram-negative cells can be sensitized to several external agents. Although antimicrobial activity of plant-derived phenolic compounds has been widely reported, their mechanisms of action have not yet been well demonstrated. The aim of our study was to elucidate the role of selected colonic microbial metabolites of berry-derived phenolic compounds in the weakening of the Gram-negative OM. The effect of the agents on the OM permeability of Salmonella was studied utilizing a fluorescence probe uptake assay, sensitization to hydrophobic antibiotics, and lipopolysaccharide (LPS) release. Our results show that 3,4-dihydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 3-(3,4-dihydroxyphenyl)propionic acid (3,4-diHPP), 3-(4-hydroxyphenyl)propionic acid, 3-phenylpropionic acid, and 3-(3-hydroxyphenyl)propionic acid efficiently destabilized the OM of Salmonella enterica subsp. enterica serovar Typhimurium and S. enterica subsp. enterica serovar Infantis as indicated by an increase in the uptake of the fluorescent probe 1-N-phenylnaphthylamine (NPN). The OM-destabilizing activity of the compounds was partially abolished by MgCl2 addition, indicating that part of their activity is based on removal of OM-stabilizing divalent cations. Furthermore, 3,4-dihydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, and 3,4-diHPP increased the susceptibility of S. enterica subsp. enterica serovar Typhimurium strains for novobiocin. In addition, organic acids present in berries, such as malic acid, sorbic acid, and benzoic acid, were shown to be efficient permeabilizers of Salmonella as shown by an increase in the NPN uptake assay and by LPS release.     

Preferential sorption of phenolic phytotoxins to soil: implications for altering the availability of allelochemicals

Allelopathy, secondary metabolite-mediated plant-to-plant interaction, is gaining application in current agricultural science as well as in invasion ecology. However, the role of sorption to soil in modifying the bioavailability of components in complex allelochemical mixtures is still obscure. Hence, the role of preferential sorption to soil in altering the chemical composition of plant exudates was studied in a silt loam soil using representative mixtures of plant phenolic acids, namely, hydroxybenzoic acid, vanillic acid, coumaric acid, and ferulic acid. The experiment was conducted using a batch equilibration technique, and data were fitted to a Freundlich isotherm. The concentration-dependent sorption coefficient (K(d)) at 10 microg mL(-)(1) was used to assess the sorption affinity of phenolic acids across different systems. Along with solid phase dissolution, all of the phenolic acids exhibited strong site-specific sorption, as evident from their nonlinear isotherms. Removal of organic matter substantially decreased the sorption affinity of all phenolic acids. Direct competition for sorption sites was observed even at low concentrations of phenolic acids. The K(d) of hydroxybenzoic acid was decreased more than 90% in the presence of coumaric acid. About 95% of sorbed vanillic acid was displaced into the soil solution in the presence of ferulic acid. Hydroxybenzoic acid did not affect the sorption affinity of other phenolic acids significantly, whereas ferulic acid showed low displacement by other phenolic acids. The displacement pattern indicated directional sorption of phenolic acids with -OH and -COOH groups. Soil organic matter was associated with preferential sorption. This is the first study to elucidate competitive sorption characteristics of plant secondary metabolites in soil matrix. The results demonstrate that preferential sorption to soil can alter the availability of plant exudates in mixtures and thus may mediate their phytotoxic effects.     

New bitter-masking compounds: hydroxylated benzoic acid amides of aromatic amines as structural analogues of homoeriodictyol

Starting from the known bitter-masking flavanones eriodictyol and homoeriodictyol from herba santa some structurally related hydroxybenzoic acid amides of benzylamines were synthesized and evaluated as masking agents toward bitterness of caffeine by sensory methods. The closest structural relatives of homoeriodictyol, the hydroxybenzoic acid vanillylamides 5-9, were the most active and were able to reduce the bitterness of a 500 mg L(-1) caffeine solution by about 30% at a concentration of 100 mg L(-1). 2,4-Dihydroxybenzoic acid vanillylamide 7 showed a clear dose-dependent activity as inhibitor of the bitter taste of caffein between 5 and 500 mg L(-1). Additionally, it was possible to reduce the bitterness of quinine and salicine but not of the bitter peptide N-l-leucyl-l-tryptophan. Combinations of homoeriodictyol and amide 7 showed no synergistic or antagonistic changes in activity. The results for model compound 7 suggested that the hitherto unknown masking mechanism is probably the same for flavanones and the new amides. In the future, the new amides may be alternatives for the expensive flavanones to create flavor solutions to mask bitterness of pharmaceuticals or foodstuffs.     

人GJB2分子进化与耳聋遗传效应的关联性分析

间隙连接蛋白β2（GJB2）基因突变与遗传性非综合征性耳聋密切相关,其广泛的突变类型及特异性的热点突变被认为是一种独特的致聋基因。本研究应用生物信息学方法对17个物种的GJB2蛋白进行了系统发育、保守性、跨膜区结构、三维结构和错义突变的分析,并结合已有报道的实验结果进行关联性分析。分析预测获得了166个固定的氨基酸位点、2个非保守区以及2个空间结构保守位点;关联性分析证实发生在保守位点的突变致病性高,非保守区突变的概率致病性小,跨膜区且改变氨基酸性质的突变,可能影响蛋白的空间结构而改变膜通道的通透性。本文为进一步研究GJB2基因突变与聋病的关联性及分子发病机制提供了理论依据,同时,这种研究思路对其它疾病的相关研究具有一定的借鉴价值。     

Comparison of the evolution of low molecular weight phenolic compounds in typical Sherry wines: Fino,Amontillado, and Oloroso

Changes in the content of low molecular weight phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, aldehydes, and their esterified derivatives, tyrosol and 5-(hydroxymethyl)-2-furaldehyde) during the aging of three different classes of Sherry wine, Fino, Oloroso, and Amontillado, have been studied. The samples studied were taken from each of the scales of the particular aging system applied to the three classes of wine. Clear differences were observed in the behavior of the low molecular weight phenolic in the three classes of wine. The wines subjected to oxidative aging presented a higher phenolic content overall, with the exception of the esterified derivatives of phenolic compounds that are mainly found in the samples that have not undergone any process of oxidation. MANOVA results confirmed that there are significant differences between all of the samples of the three types of wines. Using LDA, a classification of 100% of the samples has been made.     

空间诱变和γ射线辐照与离体培养相结合对水稻生物学效应的研究

利用返回式人造卫星搭载早籼品种中优早 3号干种子 ,研究比较其用不同剂量γ射线辐照对水稻的生物学效应。结果表明 ,空间诱变对M1 代成苗率、苗高和结实率的生理损伤明显比γ射线辐照轻 ,M2 代诱发的叶绿素缺失、株高及抽穗期突变的频率不及 30 0Gyγ射线处理。对空间诱变种子进行离体培养 ,叶绿素缺失和株高突变的频率有较大提高。空间诱变种子的愈伤组织经辐照处理后 ,绿点分化率和绿苗分化率下降 ,M2 的叶绿素缺失、株高及抽穗期突变频率超过空间诱变与离体诱变单独处理之和 ,也不同程度高于 30 0Gyγ射线辐照     

Metabolism of phenolic compounds during loquat fruit development.

Phenolic compounds in loquat fruit were identified as 5-caffeoylquinic acid (chlorogenic acid), neochlorogenic acid, hydroxybenzoic acid, 5-p-feruloylquinic acid, protocatechuic acid, 4-caffeoylquinic acid, epicatechin, o-coumaric acid, ferulic acid, and p-coumaric acid. Neochlorogenic acid was found to be dominant in the early stages of loquat fruit development. Both the concentrations and types of phenolic compounds were high in young fruit but then decreased steadily during growth. However, the concentration of chlorogenic acid increased during ripening and became predominant in ripe fruit. The large rise in chlorogenic acid concentration appears to be a characteristic of loquat fruit ripening. In all of the cultivars tested, the types of phenolic compounds were similar but the total phenolic content varied from 81.8 to 173.8 mg/100 g of fresh pulp. In the biosynthetic pathway of chlorogenic acid, the enzyme activities of phenylalanine ammonia-lyase (PAL), 4-coumarate:CoA ligase (CL), and hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase (CQT) were high at the early stage of growth, diminished to low levels approximately 3 weeks prior to harvest, but then rose to a peak at 1 week before harvest. The changes of these enzyme activities seemed to be associated with variations in chlorogenic acid concentration during development, maturation, and ripening of loquat fruit.     

Phenolic compounds and browning in sherry wines subjected to oxidative and biological aging

The composition in hydroxybenzoic and hydroxycinnamic acids, hydroxycinnamic esters, tyrosol, syringaldehyde, and flavan-3-ol derivatives of three different types of sherry wine obtained by aging of the same starting wine under different conditions was studied. So-called "fino" wine was obtained by biological aging under flor yeasts, "oloroso" wine by oxidative aging, and "amontillado" wine by a first stage of biological aging followed by a second oxidative step. On the basis of the results, the wines subjected to oxidative aging exhibited higher phenol contents, in addition to scarcely polar compounds absorbing at 420 nm that were absent in the wines obtained by biological aging. Taking into account that flavan-3-ol derivatives play an important role in wine browning, a model catechin solution was inoculated with flor yeast which, contrary to the findings of other authors in the absence of yeasts, formed no colored compounds. This different behavior may account for the resistance to browning of pale sherry wines in the presence of flor yeasts.     

Capability of Lactobacillus plantarum IFPL935 to catabolize flavan-3-ol compounds and complex phenolic extracts

Lactobacillus plantarum IFPL935 was incubated with individual monomeric flavan-3-ols and dimeric A- and B-type procyanidins to identify new metabolites and to determine the effect of compound structural features on bacterial growth and catabolism. Complex extracts rich in A-type proanthocyanidins and phenolic acids from cranberry were also tested. The results showed that L. plantarum IFPL935 exhibited higher resistance to nongalloylated monomeric flavan-3-ols, A-type dimeric procyanidins, and cranberry extract than to (-)-epicatechin-3-O-gallate and B-type dimeric procyanidins. Despite these findings, the strain was capable of rapidly degrading (-)-epicatechin-3-O-gallate, but not A- or B-type dimeric procyanidins. However, it was able to produce large changes in the phenolic profile of the cranberry extract mainly due to the catabolism of hydroxycinnamic and hydroxybenzoic acids. Of most relevance was the fact that L. plantarum IFPL935 cleaved the heterocyclic ring of monomeric flavan-3-ols, giving rise to 1-(3',4'-dihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)propan-2-ol, activity exhibited by only a few human intestinal bacteria.     

Food grade fungal stress on germinating peanut seeds induced phytoalexins and enhanced polyphenolic antioxidants

The effects of food grade fungus Rhizopus oligosporus stress on phytochemicals and phytoalexins of germinating peanut seeds were investigated by comparing the metabolic profiles of ungerminated (UG), germinated (G), and germinated seeds under fungal stress (GS). Three types of peanut seeds with different skin color (red, reddish brown, and black) were compared in the process. The polyphenolic contents were analyzed and correlated with antioxidant capacity for specific free radicals including peroxyl radical ROO(?) (ORAC), hydroxyl radical HO(?) (HORAC), superoxide radical O(2)(?-) (SORAC), and DPPH radical. The polyphenolic fingerprints analyzed by HPLC and LC-MS(n) showed that phenolic acids (coumaric, sinapinic, and ferulic acids derivatives) were the major group of phenolic compounds in ungerminated seeds. G or GS increased the level of phenolic acids, phytoalexins, and antioxidant capacity values in reddish and red peanuts but not in black peanuts. From the LC-MS(n) spectral data, 45 compounds were identified tentatively in the germinated peanuts, including 14 coumaric acids, 3 ferulic acids, 4 sinapinic acids, 2 hydroxybenzoic acids, 1 caffeic acid, 2 flavonoids, and 19 stilbenoids derivatives. Reddish brown germinated peanuts produced the highest amount of phytoalexins after GS with 55 compounds detected. Forty-five of these compounds were suggested as stilbenoid phytoalexins derivatives. The high content of phytoalexins may enhance the bioactivity of peanut seeds as functional food ingredients.     

Comparisons of soil organic matter and its fractions by pyrolysis mass-spectrometry

Pyrolysis mass-spectra from a sample of the A₁-horizon of a soil from southern Spain showed predominant peaks related to furan derivatives similar to those observed from complex polysaccharides in which not only hexoses but also pentoses and deoxyhexoses were constituent units. Smaller peaks, typical for protein materials and phenolic units, were also observed. On the other hand, typical peaks for the methoxyphenols of lignins were very small and indicated only limited amounts of undecomposed lignin residues in this soil sample. Peaks related to benzene or toluene were also very small.Humic acid samples from this soil showed much more prominent signals related to protein materials, benzene and phenolic derivatives and weaker polysaccharide-related signals than did the entire sample. Typical lignin related peaks were small or insignificant. Spectra from the grey or brown humidic acid fractions were much like those of the parent humic acid. Brown humic acid, however, showed stronger signals for nitrogen and sulphur compounds, indicating a higher content of protein-like materials in this fraction. Preparations of humic acid hydrolyzed by 6 N HCl showed in their pyrolysis products a marked increase in phenols and methoxyphenols.In its pyrogram, humin resembled humic acid, but signals for complex polysaccharides were more evident. Lignin-like materials seem not to be higher in this fraction. Hymatomelanic acid showed prominent signals related to polysaccharides and lignin. Pyrograms from the soil polysaccharides showed the characteristic pattern of a complex polysaccharide with the presence of fragments from polymers of amino acids or amino sugars. Fulvic acid spectra showed obvious dissimilarities to those from humic acid in that signals for protein, as well as those related to phenols, were low. Depending upon the isolation method, the fulvic acid preparations showed differing signals related to polysaccharide or phenolic materials.     

Orosensory-directed identification of astringent mouthfeel and bitter-tasting compounds in red wine

Application of sequential solvent extraction, followed by HPLC combined with the taste dilution analysis, enabled the localization of the most intense velvety astringent, drying, and puckering astringent, as well as bitter-tasting, compounds in red wine, respectively. Isolation of the taste components involving gel adsorption chromatography, ultrafiltration, and synthesis revealed the identification of 26 sensory-active nonvolatiles, among which several hydroxybenzoic acids, hydroxycinnamic acids, flavon-3-ol glycosides, and dihydroflavon-3-ol rhamnosides as well as a structurally undefined polymeric fraction (>5 kDa) were identified as the key astringent components. In contradiction to literature suggestions, flavan-3-ols were found to be not of major importance for astringency and bitter taste, respectively. Surprisingly, a series of hydroxybenzoic acid ethyl esters and hydroxycinnamic acid ethyl esters were identified as bitter compounds in wine. Taste qualities and taste threshold concentrations of the individual wine components were determined by means of a three-alternative forced-choice test and the half-mouth test, respectively.     

Reactivity of ferulic acid and its derivatives toward hydrogen peroxide and peracetic acid.

The reactions of ferulic acid and its derivatives with hydrogen peroxide and peracetic acid in lignin-retaining bleaching conditions have been investigated to determine their susceptibility to oxidative degradation. The conjugated side chain of ferulic acid and its etherified or esterified derivative was shown to be fairly stable, especially to hydrogen peroxide. The major reaction was trans-cis isomerization that possibly involved a radical mechanism but did not cause bond cleavage. The peracetic acid reaction increased the rate of trans-cis isomerization and was also accompanied by a minor cleavage of the side chain. Esterification did not have a substantial effect on the reactivity of ferulic acid, but 4-O-etherification significantly stabilized it against these two oxidants. By contrast, aldehyde substitution tremendously enhanced the susceptibility of the cinnamyl side chain to oxidative degradation, as evidenced by an intensive degradation of coniferaldehyde.     

小麦优良亲本宁麦9号的研究与利用

宁麦9号是高产稳产、适应性广、中抗赤霉病、高抗梭条花叶病的优质弱筋小麦品种,由该品种衍生的10个品种已成为或即将成为长江中下游麦区的主推品种。为探讨宁麦9号作为亲本在小麦育种上的利用价值,本文分析了该品种的高产生理基础,产量、品质和抗病性状的遗传以及其衍生品种的主要特点。结果表明,宁麦9号光合优势明显,后期叶片不易早衰,水分利用率高、抗旱性强,其高产优势表现为成穗数和穗粒数多。遗传分析表明,该品种穗粒数、收获指数、蛋白质含量、碱水保持力以及抗病性等性状的配合力高,易于传递给后代。以宁麦9号为亲本,通过不同育种方法,育种工作者先后育成了宁麦13、宁麦14、宁麦16、生选4号、生选6号、扬麦18、扬辐麦4号、镇麦5号、镇麦8号、南农0686等10个小麦新品种,这些衍生品种都保持了宁麦9号高产稳产、中抗赤霉病、抗梭条花叶病等优良特性。因此,认为:宁麦9号是一个一般配合力较高的优良亲本,对选育高产、优质、抗病小麦新品种有重要利用价值。     

Determination of Fatty Acid Composition of Turfgrass by High‐Performance Liquid Chromatography

Abstract

The fatty acid composition of warm‐season turfgrasses is physiologically regulated by environmental changes, particularly temperature. Species or cultivars, which have increased degree of unsaturation, usually have a greater freeze resistance. Quantifying fatty acid composition not only can help understand the freeze‐resistant mechanism of warm‐season turfgrasses but also in practice develop a management strategy for better turf. A high‐performance liquid chromatography (HPLC) method was developed for this purpose. The method is based on the bromophenacyl reaction of fatty acids and separation on a C8 column with gradient elution. Information on limit of identification, linearity of quantification, response factor, and derivatization conditions is presented and discussed. The method presented is simple to apply and provides an alternative to the traditional gas chromatography (GC) method. The results of fatty acid composition from a field freezing‐resistance experiment are discussed.     

履带车辆转向时最大驱动力矩的计算

履带车辆转向时不仅要克服行走阻力,还要克服转向阻力,该文对不考虑车体重心偏移时的转向驱动力矩进行了研究,并在此基础上着重研究了考虑重心偏移时的转向驱动力矩的计算方法,进行了实例计算和比较分析,可知横向偏心距对总的转向阻力矩没有影响,而纵向偏心距对其有影响,且随纵向偏心距的增加转向阻力矩减小;只考虑纵向偏心距,而不考虑横向偏心距时,转向时驱动力矩小于不考虑重心偏移时的驱动力矩;当只考虑横向偏心距,而不考虑纵向偏心距时,转向驱动力矩最大。当履带车辆原地转向,且只存在横向偏心距时靠近偏心一侧的履带的驱动力矩最大。