光谱技术在油料作物油酸含量检测中的应用

油料作物中油酸含量的高低与其品质存在很大关系。光谱技术具有快速、无损地获取目标物光谱数据的优势。从高光谱技术和近红外光谱技术两个方面介绍了光谱技术在油料作物油酸含量检测中的研究进展,分析了目前光谱技术检测油酸含量存在的问题,并对其应用前景进行了展望。     

光谱技术在花生品质检测中的应用研究进展

综述了应用光谱技术进行花生品质快速检测的主要研究成果和发展趋势,介绍了光谱技术检测花生蛋白质、水分、含油量三个方面的研究进展,讨论了光谱技术在花生无损检测及选育方面的研究前景。     

近红外光谱技术及其在茶叶上应用研究

本文主要介绍了近红外光谱技术的发展历程和特点,以及近红外技术在茶叶上应用研究现状,并指出近红外光谱技术在茶叶上有着广阔的应用前景。     

光谱分析和光谱成像技术检测大豆品质的研究进展

光谱分析和光谱成像技术结合了化学计量学方法,可以用于检测物质中各成分的含量.随着我国大豆产业不断发展,光谱分析和光谱成像技术已应用到大豆品质检测技术的各个方面.本文介绍光谱分析和光谱成像技术的基本原理;归纳技术检测工艺,包括大豆检测状态、光谱预处理方法、光谱特征提取方法和常用建模分析方法;重点总结光谱分析和光谱成像技术...     

近红外光谱及高光谱技术在茶叶上的应用

光谱技术作为一种绿色、快速、高效、准确的无损检测技术,在茶叶及茶制品的理化检测、品质评价等方面显现出较大的应用潜力.综述了近红外光谱及高光谱技术在茶叶理化成分定量分析,茶叶种类、产地及品种的判别以及茶叶等级判别等方面的应用和研究进展,同时对该技术在茶叶上的应用前景进行展望.     

化学指纹图谱在茶叶中的应用

针对目前市场上茶叶产品较为混乱,对目前在茶叶品种与产地鉴别以及质量监控中具有广阔应用前景的化学指纹图技术做一综述,介绍基于高效液相色谱、近红外光谱、质谱、核磁共振等技术的指纹图谱在茶叶识别中的作用,并对指纹图谱的解析方法做了简要介绍,总结了化学指纹图谱在茶叶中的应用前景。     

近红外光谱技术在农产品品质检测中的应用

近红外光谱技术是一种新型的无损检测技术,在许多领域都得到了很好的应用。本文从农产品中各种物质成分含量预测、分类鉴别、腐烂鉴别、实时监测几个方面综述了近红外光谱技术在农产品品质检测上的应用,并对其在仪器硬件的研究和开发、化学计量学方法的探索与研究以及快速在线检测方法的研究等方面的发展趋势进行了展望。     

甜菜氮素营养及诊断技术研究进展

综述了目前国内甜菜生产中增施氮肥的积极作用及过量施氮存在的问题,同时介绍了国际国内作物氮素营养诊断的各种方法,重点介绍了当前较为先进的高光谱技术在农作物氮含量监测中的应用。提出借鉴其他作物生产栽培中运用高光谱技术对其氮含量进行监测的方法,为甜菜植株氮含量实时监测提供一种新的快速、有效的方法,为实现甜菜丰产高糖奠定基础。     

近红外光谱分析技术在稻米品质测定和遗传分析中应用研究概述

近红外光谱定量分析技术是一项高效、快速检测样品中化学成分的方法,在米质组分检测、快速筛选育种材料等方面得到广泛应用。文章简要介绍了该技术的基本原理、定量分析的步骤及其在稻米品质改良中的应用。近红外技术不仅能提高育种材料选择效率,而且还有助于品质遗传机理研究的深入,加速稻米品质改良进程。     

学术交流

２００２年１０月１４日 ,广西大学和广西制糖学会安排福斯公司糖业快速分析技术的专家组前来南宁举办了“现代糖业生产品质快速监控技术交流会”。会议的主要内容有 :１．近红外光谱快速分析技术简介 ;２．糖业快速品质分析新技术 ;３．广西大学糖业工程技术研究中心关于应用近红外光谱技术的研究介绍。最后 ,与会代表还与专家们交流了近红外技术及设备的各种技术和应用问题学术交流     

Causes of variation in the rate of increase of wheat harvest index

Several crop simulation models calculate grain yield by assuming that the rate of change of harvest index (δHI/δt) is constant (at rate k) during grain growth. Such behaviour has been identified in many crops, although the literature contains many examples of variations in k. The concept is useful if it approximates the truth in most circumstances, or if departures from both linearity and constancy are predictable from either the environment or the state of the crop. In this paper we examine the hypothesis that much of the variation in k is related to both crop biomass at the start of grain filling (BGF) and the crop growth rate during grain growth (CGF). Calculations using simple partitioning rules indicated that both factors are important. We showed that k increases rapidly as BGF decreases below about 9.0 Mg DM/ha, but decreases only slowly with increases of BGF above 9.0 Mg DM/ha. The analysis also showed that the increase in HI with time is quadratic rather than linear. We analysed data from 68 field grown wheat crops with variation in cultivar, location, irrigation, ambient CO₂ concentration and sowing dates. These showed an almost three-fold variation in k (0.0058–0.0164 day⁻¹). Across all data sets, there was a negative linear relationship (y = 0.02 − 0.0006x, R² = 0.41, p < 0.001) between k and BGF. Overall, these results suggest that some of the variation in k can be accounted for by differences in BGF. We suggest that any model that uses harvest index change as a basis for calculating yield should account, at least, for variations in BGF.     

Valorization of three varieties of grape

In the present investigation, seed methanolic extracts of three Vitis vinifera (Muscat d’Italie, Syrah and Carignan) were assayed for their antioxidant activities. Results showed that there are strong variations in the contents of total phenols (440.97–121.94 mg GAE g⁻¹ DW), flavonoids (48.07–16.81 mg EC g⁻¹ DW) and tanins (37.15–14.9 mg EC g⁻¹ DW) from the studied seeds. The phenolic composition of these extracts was determined by RP–HPLC after acid hydrolysis. The main phenolic compound was quercetin with 27.2% in Muscat d’Italie, 48.8% in Syrah and 28.4% in Carignan. Besides, all seed extracts showed remarkable DPPH radical scavenging activity with IC₅₀ values ranged from 1.8 to 30 μg ml⁻¹. EC₅₀ values of reducing power activity ranged from 100 to 120 μg ml⁻¹. The high phenolic content and the considerable antioxidant activities of vitis seed extracts could potentially be considered as an expensive source of natural antioxidants.     

Host ranges of North American isolates of Penicillium causing blue mold of bulb crops

Single isolates of four Penicillium species belonging to series Corymbifera (Penicillium allii, Penicillium hirsutum, Penicillium tulipae, Penicillium venetum) plus an isolate of Penicillium polonicum, all from North American sources, were inoculated individually into Crocus sativus (crocus), Allium sativum (garlic), Allium cepa (onion), Allium stipitatum (ornamental onion), Iris hollandica (iris), Ornithogalum umbellatum (grass lily), and varieties of Gladiolus (gladiolus), Tulipa (tulip) and Narcissus (daffodil). All isolates were pathogenic to garlic and onion (but none to ornamental onion), and all but P. polonicum to Tulipa, although virulence varied considerably. Additionally, P. hirsutum was pathogenic to Crocus, Gladiolus and Iris; P. tulipae to Narcissus, Crocus, Ornithogalum and Iris; P. venetum to Gladiolus, Ornithogalum and Iris; and P. polonicum to Iris. Nomenclature and taxonomy of series Corymbifera are summarized, the above results compared to similar investigations in Europe, and management implications provided.     

A reassessment of the electrophoretic mobility of high molecular weight glutenin subunits of wheat

The high molecular weight subunits of wheat glutenin (HMW-GS) are important for bread-making quality. Their composition is routinely identified by Tris-glycine SDS-PAGE after reduction of glutenin disulfide bonds. However, the relation between their molecular weight and, hence, their primary structure, and their mobility in Tris-glycine SDS-PAGE has proven to be ambiguous. We demonstrate a Bis-Tris SDS-PAGE procedure with a neutral, instead of alkaline, pH in the gel and running buffers. In this method commonly occurring HMW-GS from wheat migrated in the order 5 > 2 ≈ 3 > 1 > 6 ≈ 2* > 7 > 8 > 9 > 12 > 10, which is different from the order obtained in the Tris-glycine system. HMW-GS were identified by N-terminal sequencing after isolation with RP-HPLC. Protein sequences of HMW-GS were further confirmed by LC-MS/MS analyses of chymotryptic peptides after comparing the MS data to amino acid sequences in protein databases. The numbers of amino acids of HMW-GS reflected well the mobility order in Bis-Tris SDS-PAGE. The results indicate that Bis-Tris SDS-PAGE may not only be used to identify HMW-GS, but also to estimate the length of their polypeptide chain, as such avoiding previously observed anomalies in migration order.     

Influence of Core Oligosaccharide of Lipopolysaccharide to Outer Membrane Behavior of Escherichia coli

Lipopolysaccharides, major molecules in the outer membrane of Gram-negative bacteria, play important roles on membrane integrity of the cell. However, how the core oligosaccharide of lipopolysaccharide affect the membrane behavior is not well understood. In this study, the relationship between the core oligosaccharide of lipopolysaccharide and the membrane behavior was investigated using a series of Escherichia coli mutants defective in genes to affect the biosynthesis of core oligosaccharide of lipopolysaccharide. Cell surface hydrophobicity, outer membrane permeability, biofilm formation and auto-aggregation of these mutant cells were compared. Compared to the wild type W3110, cell surface hydrophobicities of mutant ΔwaaC, ΔwaaF, ΔwaaG, ΔwaaO, ΔwaaP, ΔwaaY and ΔwaaB were enhanced, outer membrane permeabilities of ΔwaaC, ΔwaaF, ΔwaaG and ΔwaaP were significantly increased, abilities of biofilm formation by ΔwaaC, ΔwaaF, ΔwaaG, ΔwaaO, ΔwaaR, ΔwaaP, ΔwaaQ and ΔwaaY decreased, and auto-aggregation abilities of ΔwaaC, ΔwaaF, ΔwaaG, ΔwaaO, ΔwaaR, ΔwaaU, ΔwaaP and ΔwaaY were strongly enhanced. These results give new insight into the influence of core oligosaccharide of lipopolysaccharide on bacterial cell membrane behavior.     

Comparison of resistance toFusarium spp. of glasshouse-and field-grown tuber progenies of potato

Summary Field-grown tubers of 22 progenies ofSolanum tuberosum L. generated in a crossing programme involving seven parents differing in resistance toFusarium coeruleum Lib. ex Sacc. andF. sulphureum Schlect. (=F. sambucinum Fuckel, teleomorphGibberella pulicaris (Fr.) Sacc.) were wound-inoculated with a cornmeal + sand culture of each pathogen. Parental genotypes were also included. The mean lesion size of each progeny was compared in 2 years of tests, as well as with published data on glasshouse-grown tubers. ForF. coeruleum there was a high correlation between years as well as with the glasshouse data, but no such correlations were apparent withG. pulicaris. Furthermore, parental and GCA values, as well as progeny means and mid-parent scores, also correlated highly forF. coeruleum but not forG. pulicaris. Glasshouse-grown tubers of 11 wildSolanum spp. were also inoculated with both pathogens. Some resistance to one or other, or both, was apparent, particularly inS. chacoense.     

Total Synthesis of Gobiusxanthin Stereoisomers and Their Application to Determination of Absolute Configurations of Natural Products: Revision of Reported Absolute Configuration of Epigobiusxanthin

(3R)-Gobiusxanthin stereoisomers (1a–d) were synthesized by stereoselective Wittig reaction of the (3R)-C₁₅-acetylenic tri-n-butylphosphonium salt 7 with C₂₅-apocarotenal stereoisomers 5a,b and 14a,b bearing four kinds of 3,6-dihydroxy-ε-end groups. The validity of the reported stereochemistry of gobiusxanthin was demonstrated by the fact that the reported spectral data of natural gobiusxanthin were in agreement with those of synthetic (3R,3''S,6''R)-gobiusxanthin (1a). On the other hand, the reported CD spectral data of natural epigobiusxanthin, which has been assigned as (3R,3''R,6''R)-isomer (3''-epigobiusxanthin), were identical with those of synthetic (3R,3''S,6''S)-isomer 1d (6''-epigobiusxanthin) rather than those of the corresponding synthetic 3''-epi-isomer 1b. It was found that the stereochemistry at C3-position has little effect on the shape of their CD spectra. Thus, in order to reinforce the validity of the absolute configurations at C3-position of natural specimens, (3S,3''S,6''R)- and (3S,3''S,6''S)-stereoisomers 1e and 1f were also synthesized and a HPLC analytical method for four stereoisomers was established by using a column carrying a chiral stationary phase. The HPLC analysis has proven that the stereochemistry of the natural epigobiusxanthin is 3R,3''S,6''S.     

Comparison of the impact of dextran and reuteran on the quality of wheat sourdough bread

This study investigates the influence of in situ exopolysaccharides (EPS) and organic acids on dough rheology and wheat bread quality. Dextran forming Weissella cibaria MG1 was compared to reuteran forming Lactobacillus reuteri VIP. For in situ production of EPS, sourdoughs were supplemented with 15% sucrose. Control sourdoughs were prepared with the same strain but without sucrose. W. cibaria MG1 and L. reuteri VIP formed 5.1 and 5.8 g kg⁻¹ dextran and reuteran, respectively. Formation of EPS from sucrose led to production of high amounts of acetate by L. reuteri VIP, but only small amounts were detected in W. cibaria MG1 sourdough. EPS containing sourdough or control sourdough was incorporated at 10% and 20% in wheat dough. EPS significantly influenced the rheological properties of the dough, with dextran exhibiting the strongest impact. The addition of dextran enriched W. cibaria MG1 sourdough significantly increased CO₂ production, whereas increased acidity in reuteran containing dough reduced gas production. The quality of wheat bread was enhanced when 10% of L. reuteri-sucrose sourdough was added. The positive effect of reuteran was masked by increased acidification after 20% sourdough addition. Incorporation of dextran enriched sourdough (10% and 20%) provided mildly acidic wheat bread with improved bread quality.     

Effect of physiological age on growth vigour of seed potatoes of two cultivars. 5. Review of literature and integration of some experimental results

Summary The most important literature on physiological age is discussed and an attempt is made to describe the relationship between the chronological age and growth vigour of seed of cvs. Jaerla and Désirée produced in three seasons and stored at 4 or 12°C in darkness. The seed of both cultivars reaches maximum growth vigour earlier when stored at 12°C, although this effect is greater in Jaerla than in Désirée. In both cultivars, storage at 12°C gives a lower maximum growth vigour and a shorter duration than storage at 4°C. Sprouting capacity seems to be the best measure of growth vigour, although peroxidase activity could also be a measure of growth vigour beyond its maximum. The incubation period might be useful to indicate the beginning and end of the phase of maximum growth vigour.

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Zusammenfassung Nach Durchsicht der wichtigsten Literatur über das physiologische Alter von Kartoffeln wird der Versuch gemacht, Ergebnisse über Untersuchungen an Pflanzknollen der Sorten Jaerla und Désirée in drei Wachstumsperioden sowie bei 4°C und 12°C zu integrieren (Hartmans & van Loon, 1987; van Es & Hartmans, 1987: Bodlaender & Marinus, 1987: van Loon, 1987). Zuerst werden die Zusammenh?nge zwischen dem chronoligischen Pflanzgutalter und den Pflanzen- bzw. Knollenwachstums-Merkmalen verglichen. Wichtige Elemente für die Beschreibung der Zusammenh?ngen zwischen Pflanzgutalter und Wachstumsintensit?t sind (1) das Ende der Ruheperiode. (2) der Anfang und das Ende des Maximums von einigen Knollen- und Pflanzenwachstums-Charakteristika (Tabelle 1), (3) die Zusammenh?nge zwischen dem Pflanzgutalter (Lagerungstage) und Keimungskapazit?t, Auflauf, Triebl?nge. Zahl der Triebe, Blattfl?chen-Index und gesamtem Pflanzegewicht rund 60 Tage nach Pflanzung (Hartmans & van Loon, 1987; Bodlaender & Marinus, 1987) und (4) die Zahl der Lagerungstage, bis einige oder alle gepflanzten Saatknollen ersch?pft sind (Tabelle 1). Aufgrund dieser Elemente wurde ein m?gliches Modell für den Zusammenhang zwischen Pflanzgutalter und relativer Wachstumsintensit?t (RGV) entwickelt (Abb. 2). Abbildung 2 zeigt klar, dass h?here Lagertemperatur (12°C) das Altern der Knollen beider Sorten underschiedlich beschleunigt. Dafür wurde des Ausdruck ‘physiologisches Alter’ übernommen. H?here Lagertemperatur f?rdert die maximale RGV für Saatknollen beider Sorten, obwohl Jaerla betr?chtlich st?rker als Désirée reagiert. Obwohl Désiréc ihre maximale RGV bei 12°C früher erreicht als bei 4°C, ist der RGV bei 4 °C-Lagerung im gleichen Moment h?her als der von Knollen, die bei 12°C gelagert werden. Desweiterent ist von Interesse, dass die maximale RGV bei beiden Sorten durch die h?here Temperatur gesenkt wird, und dass h?here Temperature die L?nge der Periode mit maximaler RGV verkürzt. Keimungskapazit?t und Inkubationsperiode zeigten im Ganzen die h?chsten Korrelationen mit der Wachstumsintensit?t (GV). w?hrend die Peroxydase-Aktivit?t auch dann gut korrelierte, nachdem die GV sich von ihrem Maximum entfernt hatte (Tabellen 4–6). Man kann annehmen, dass diese Studie die Keimungskapazit?t als bestes Mass zur Bestimmung der GV darstellt. Die Inkubationsperiode erscheint als brauchbare Methode zur Bestimmung des Anfangs und des Endes der Periode mit maximaler GV (Tabelle 7), welehe ein wichtiges Charakteristikum jeder Sorte ist. Der Einfluss des physiologischen Alters der Saatknollen auf den sp?teren Knollenertrag scheint oft gering zu sein. Den Ergebnissen dieser Studie und der Literatur zufolge wird angenommen, dass Pflanzgut mit ‘unterschiedlichem’ physiologischem Alter in Wirklichkeit noch an oder nahe an der maximalen GV ist: das war mit Pflanzgut von Désirée in unseren Versuchen der Fall. Zus?tzlich kann mit Madec (1981) angenommen werden, dass im zweiten Teil des Wachstumszyklus andere ertragsbestimmende Faktoren oft über die GV des Pflanzgutes dominieren.

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Résumé Après avoir passé en revue les plus importants articles de la littérature concernant l'age physiologique des tubercules, une tentative est faite pour intégrer les résultats des études sur les tubercules de semence de deux variétés, Jaerla et Désirée, produites pendant trois saisons et conservées à 4°C et 12°C (Hartmans & van Loon, 1987; van Es & Hartmans, 1987: Bodlaender & Marinus, 1987; van Loon, 1987). Premièrement, les relations entre l'age chronologique du plant et les caractéristiques se rapportant au développement du tubercule et de la plante sont comparées. Les éléments importants pour décrire les relations entre l'age du plant et la vigueur de croissance sont (1) la fin de la période de repos végétatif (2) le début et la fin du maximum atteints par quel-ques caractéristiques de croissance du tubercule et de la plante (tableau 1), (3) les relations entre l'age du plant (jours de conservation) et la capacité germinative, la levée, la longueur des tiges, le nombre de tiges, l'index de surface foliaire et le poids sec total de la plante environ 60 jours après la plantation (Hartmans & van Loon, 1987; Bodlaender & Marinus, 1987) et (4) le nombre de jours de conservation jusqu'à ce que quelques ou tous les tubercules plantés soient épuisés (tableau 1). Sur la base de ces éléments un modèle possible pour établir une relation entre l'age du plant et la vigueur de croissance relative (RGV) peut être établie (figure 2). La figure 2 montre clairement qu'une température de conservation élevée (12°C) accélère différemment le vieillissement des tubercules de semence de deux variétés. Par conséquent, le terme ‘age physiologique’ est adopté. Les plus hautes températures de conservation avancent la vigueur de croissance relative pour les deux variétés, bien que Jaerla réagisse considérablement plus fortement que Désirée et que celle-ci conservée à 12°C atteigne son maximum plus rapidement qu'à 4°C, la RGV du plant conservé à 4°C est à ce moment plus élevéc que celle du plant maintenu à 12°C. De plus, il est intéressant de noter que pour les deux variétés une température de conservation plus haute diminue la RGV maximum et raccoureit sa durée. La capacité germinative et la période d'incubation ont montré les corrélations les plus élevées avec la vigueur de croissance, tandis que l'activité péroxydasique présente une bonne corrélation avec la vigueur de croissance passé le maximum (tableux 4–6). On en conclut que cette étude fait appara?tre la capacité germinative comme la meilleure mesure pour déterminer la vigueur de croissance. La durée d'incubation constitue une méthode utile pour évaluer le début et la fin de la phase avec le maximum de la vigueur de croissance: ce dermier étant une caractéristique importante de chaque variété. Il semble que l'effet de l'age physiologique des tubercules de semence sur le rendement final en tubercules est souvent faible. Sur la base des résultats de ces essais et de la littérature on peut supposer que les plants d'ages physiologiques différents sont en réalité souvent au maximum ou près du maximum de la vigueur de croissance; cela est le cas du plant de la variété Désirée dans nos expériences. De plus on peut supposer, comme Madec (1981), que dans la seconde partie du cycle végétatif d'autres facteurs déterminant le rendement prédominent souvent sur la vigueur de croissance du plant.

     

Assessment of commercial milling potential of hard wheat by measurement of the rheological properties of whole grain

The single-kernel characterisation system (SKCS) 4100 instrument has previously been shown to provide in situ measurements of the rheological properties of the bran and endosperm layers of wheat, otherwise only possible following their isolation by dissection or machining. The current study has confirmed that endosperm maximum stress (endosperm strength (ES) as measured using the SKCS 4100 correlates highly (r=0.898$r=0.898$) with compressive strength (maximum stress, σ_max) measurements performed on specimens of endosperm tissues of known dimensions, isolated from different subsamples of the same bulk wheat samples. This provides a means of scaling the stress axis of the crush–response profile plots to the Instron scale (MPa) so that the SKCS endosperm stress/strain curves for hard wheat, soft wheat and durum can be compared with Instron results presented in the literature. In addition, a simple method for the measurement of ES and stiffness, using the SKCS 4100, has been developed. The method has been shown to rank wheat samples according to their performance when processed on a 650 kg/h pilot mill. The criterion against which the SKCS-derived rankings were compared was the Milling Quality Index, which uses both the percentage flour extraction and Branscan speck count measurements.