Werner-type metal complexes of potato starch

It was shown that potato starch formed Werner‐type complexes. In these complexes a metal atom is ligated by the lone electron pairs of hydroxyl groups from d ‐glucose units and phosphate groups in starch. Acetate, chloride and nitrate were counter‐ions to the transition metal atoms. The metal cations bound preferentially to the phosphoric acid moiety of amylopectin, but secondarily they were co‐ordinated by the hydroxyl groups of the d ‐glucose units. This resulted in the formation of clathrate cages in which a significant number of the water molecules were trapped. Such structures were able to co‐ordinate further metal cations. Only Mn(II) and Co(II) ions, with acetate counter‐ions, neither formed clathrate cages nor were co‐ordinated by the hydroxyl groups of the d ‐glucose of starch.     

INFLUENCE OF FLAVORING ON THE VISCOELASTIC PROPERTIES OF STARCH GELS DURING GELATION AND LONG-TIME RETROGRADATION

The effect of three different aroma compounds on the texture of starch dispersions during gelation and retrogradation was studied. Oscillatory measurements were used to follow gelation and to check the structure of the starch dispersions after retrogradation up to 28 days. Rheological tests did not indicate any effect of the presence of any of the aroma compounds on the mechanism of gelation. During long‐time retrogradation, some added aroma compound did. We assume that this is a consequence of the ability of aroma compounds to form a complex or to show another type of interaction with starch molecules like entrapment in the amorphous regions of starch. Linalool is known to form complexes with amylase, but did not induce texture modifications, probably because, in our experiments, the added amount of this compound was too low. Isoamyl acetate, which according to literature interacts with amylopectin, exhibited a weak effect after 3 or 4 weeks, depending on the amount added. Octanal also increased gel stiffness after 3 weeks. This phenomenon is consistent with the observation that this aroma compound can form complexes with starch as demonstrated by X‐ray diffraction in this study.     

淀粉-多酚复合物制备及其消化特性研究进展

多酚是一种从植物中提取的,具有降血糖、抗炎、抗氧化、抗癌和抗菌特性的化合物。在一定条件下,淀粉可以与多酚发生相互作用,形成两种类型的复合物。一种是非包合物,即酚类化合物的羟基和羰基与淀粉相互作用形成分子间聚集体；另一种是V型包合物,即酚类化合物部分包封在淀粉的内部疏水螺旋内。上述两种复合物均对降低淀粉消化率有积极作用,但受加工方式、淀粉和多酚种类的影响。因此,本文在总结上述因素对淀粉-多酚复合物理化及消化特性影响的基础上,指出目前淀粉-多酚复合物研究中存在的不足之处,提出进一步的研究重点,以期为淀粉-多酚复合物在不同食品中的应用提供参考。     

Furcellaran metal salts – structure,thermal properties and their ligation with coumarin

Furcellaran formed complexes with transition metal ions. The amount of bound metal ions decreased in the following order: Fe(III) > Mn(II) > Cu(II) > Cr(III) > Zn > Ni(II), thus the hardness of these Lewis acids seemed to be the most essential factor controlling their ligation with the polysaccharide. Resulting complexes decomposed thermally at lower temperature than plain furcellaran. Neither furcellaran bound coumarin selected as the model molecule for mycotoxins nor this oxacompound coordinated to furcellaran metal salts.     

红豆淀粉-脂质复合物结构及体外消化性质

将红豆淀粉与棕榈酸、硬脂酸、油酸和亚油酸4 种脂肪酸复合,采用微波处理淀粉后,使用水浴加热方法制备红豆淀粉-脂质复合物,利用扫描电子显微镜、差示扫描量热仪、傅里叶变换红外光谱及X射线衍射探讨复合物的结构变化,并测定复合物的体外消化特性。结果表明,在扫描电子显微镜下观察,与对照红豆淀粉相比,红豆淀粉-脂质复合物的体积增大,表面凹凸不平。差示扫描量热分析结果表明红豆淀粉只有单一峰,而复合物有3 个峰,证明复合物是由I型和II型复合物共同构成;糊化起始温度、峰值温度、结束温度均升高,说明加入脂肪酸抑制了淀粉的糊化;热焓随着脂肪酸碳链长度及不饱和度的增加而增大,热焓的增加可能与抗性淀粉的形成有关。傅里叶变换红外光谱分析结果表明复合物形成,氢键的增加可能使抗性淀粉含量增多。复合物产生了V型结晶结构的衍射角,晶体特性发生改变,证明了复合物的存在,添加棕榈酸、硬脂酸、油酸形成复合物的特征峰强度明显高于添加亚油酸形成复合物的特征峰强度,随着V型特征峰强度的增加,抗性淀粉含量增多。复合物的快速消化淀粉质量分数降低、缓慢消化淀粉及抗性淀粉质量分数升高,抗消化性随着脂肪酸碳链长度的增加及不饱和度的增加而降低。4 种脂肪酸对红豆淀粉结构及体外消化影响不同,其中,以棕榈酸的影响效果最为显著。本实验可为淀粉-脂质复合物的结构性质及其在抗性淀粉的应用提供参考依据。     

芦丁金属配合物的制备及抑菌活性研究

研究了芦丁与Cu(Ⅱ)、Zn(Ⅱ)、Mn(Ⅱ)形成的金属离子配合物的合成、初步表征及其抑菌活性.结果表明,配合物的组成为[M3L2(H2O)n](CH3COO)2(n=1,2,3…),配体不饱和环的3个羟基参与了金属离子的配位作用;测定其摩尔电导率和红外光谱,对其抑菌活性较为显著.     

Co-transport of metal complexes by the green mussel Perna viridis

We examined the uptake of ligand-bound metals (Cd and Zn) by the green mussel Perna viridis using defined artificial seawater. Different free ion concentrations (1 pM to 10 microM) in uptake solutions were created by adding different amounts of total metals (Cd 0.1 nM to 0.1 mM; Zn 0.5 nM to 0.05 mM) and ligands (EDTA, NTA, citric acid). Our results showed that Cd and Zn uptake could not be fully explained by the free Cd and Zn concentrations in the presence of different ligands, indicating that metal-ligand complexes were at least partially available for uptake by the mussels. Total Zn concentrations appeared to be a better predictor of metal uptake than the free Zn ion concentrations in the presence of different ligands. Uptake of lipophilic organic metal complexes was substantially greater than the hydrophilic metal complexes, even though the free ion concentration was comparable or lower. Moreover, the radiolabeled ligand compounds were directly accumulated by the mussels. The accumulation of metal complexes may explain the increased metal uptake with increasing ligand and total metal concentration, even though the free ion metal concentration was constant. Overall, our experimental results indicated that free metal ion cannot fully explain metal uptake since metal complex species were also available to the mussels to some extent, apparently through a co-transport process.     

V-amylose Structural Characteristics,Methods of Preparation,Significance, and Potential Applications

The amylose component of starch can form complexes known as V-amylose with amphiphilic or hydrophobic ligands. The V-amylose complexes are single, left-handed helices that are arranged as crystalline and amorphous lamellae, which may form distinct nano- or micron-scale structures. V-amylose has potential as a biomaterial for nanoencapsulation of sensitive bioactive and flavor ingredients, modification of rheological behavior of starch-containing products, reduction of starch retrogradation, and postprandial hyperglycaemia in diabetics. Various aspects of V-amylose structure, methods of preparation, factors that affect its formation, and the significance and potential applications of the V-amylose complexes are reviewed.     

Interaction between starch and aroma compounds as measured by proton transfer reaction mass spectrometry (PTR-MS)

The interaction between starch and the complexing aroma compounds hexanal and menthone was investigated by headspace analysis using proton transfer reaction mass spectrometry (PTR-MS). Starch systems with non-modified and modified tapioca starch were prepared containing single aroma compounds (hexanal, menthone) or a blend of the two aroma compounds at low aroma concentrations (6 × 10⁻³ mg/100 g). The headspace intensity of starch–aroma systems was slightly reduced due to starch–aroma interactions compared to aroma water-systems. The combination of hexanal and menthone did not lead to competitive aroma release effects, but hexanal retention increased by increasing the equilibration time from 48 to 96 h. Non-modified and chemically modified starch showed similar aroma release behaviour. It is concluded that the formation of starch–aroma complexes influences aroma release, but that at low aroma concentration the dissociation of the complex is not hindered by the aggregation of amylose–aroma complexes.     

低温挤压法制备玉米淀粉-GMS复合物及其回生性质研究

为解决玉米淀粉易于回生的难题,试验探讨了挤压蒸煮制备玉米淀粉酯复合物的结构和回生机理。试验结果表明:玉米淀粉-GMS复合物的回生凝胶焓值和回生凝胶温度低于原玉米淀粉的回生凝胶焓值和回生凝胶温度。X射线衍射分析原玉米淀粉属于A型衍射图,经挤压蒸煮处理制备的玉米淀粉-GMS复合物属弱V型结晶结构。FT-IR光谱的分析可知,玉米淀粉-GMS复合物的进程结晶度降低,在1735 cm~(-1)处有吸收峰,玉米淀粉与分子蒸馏单甘酯(GMS)发生酯交换反应生成了玉米淀粉-GMS复合物,分子蒸馏单甘酯能有效抑制玉米淀粉回生。随分子蒸馏单甘酯添加量的增加,分子蒸馏单甘酯对玉米淀粉回生的抑制作用增加显著。在食品工业生产中,玉米淀粉-GMS复合物是非常有应用价值抗回生的高质量淀粉基产品。     

EPR Studies of Thermally Treated Oxidized Corn Starch

The formation of radicals in oxidized corn starch at 20–250°C in air was investigated by quantitative EPR spectroscopy. It was found that the presence of carboxyl groups in the oxidized starch increases the starch's ability to generate radical species. Introducing Cu²⁺ ions into the starch, as a catalyst or as an EPR probe, leads to the formation of copper‐carboxyl complexes containing two carboxyl ligands. Drastic increase in the number of radical species at about 250°C is accompanied by a decrease in the intensity of EPR signal of Cu²⁺‐carboxyl complexes, indicating that the thermal degradation of oxidized corn starch occurs with the formation of radicals, probably via breaking the chemical bonds in the carboxyl groups.     

玉米淀粉-脂质复合物对曲奇饼干体外消化和血糖生成指数的影响

目的 探究玉米淀粉-脂质复合物的结构和消化特性以及对曲奇饼干的体外消化特性与血糖生成指数的影响。方法 利用水热法制备了制备不同脂质(包括饱和脂肪酸与不饱和脂肪酸)与玉米直链淀粉的复合物, 通过傅里叶红外光谱仪(fourier transform infrared spectroscopy, FT-IR)与X-射线衍射(X-ray diffractometer, XRD)探究了淀粉分子短程和长程有序性。结果 研究表明, 淀粉-脂质复合物的形成使快消化淀粉含量显著降低, 慢消化淀粉和抗性淀粉含量显著增加。水热法制备中通过疏水相互作用得到的淀粉-脂质复合物利用氢键链接使其结构更加稳定, 体外消化速率呈降低趋势。其中玉米淀粉-卵磷脂复合物、玉米淀粉-硬脂酸复合物与玉米淀粉-肉豆蔻酸复合物为 V+B 型晶体结构, 玉米淀粉-大豆油复合物与玉米淀粉-玉米油复合物的晶型结构未发生改变。在五种淀粉-脂质复合物中, 玉米淀粉-卵磷脂复合物的水解率最低, 水解指数预估血糖指数分别为44.65%、64.22%, 所对应的曲奇饼干的水解指数与预估血糖指数也最低, 分别为51.68%、68.08%。结论 表明玉米淀粉-卵磷脂复合物适合作为新型淀粉-脂质复合物用于开发具有低血糖指数的饼干食品。     

菠萝蜜淀粉-月桂酸复合物的理化特性研究

淀粉与油脂热加工过程中会产生大量淀粉-脂质二元复合物,这会显著影响淀粉基产品的品质、保质期、物理化学特性等.菠萝蜜是新型小颗粒、直链淀粉含量高的热带特色淀粉资源.以木薯和玉米两种淀粉与菠萝蜜淀粉同为A型结晶的淀粉作参照,探究加热过程中菠萝蜜原淀粉与月桂酸形成复合物的复合指数、糊化特性、粒径分布、颗粒形貌和短程有序性.实...     

碱法制备的4种淀粉-脂肪酸包合物的热力学性质研究

采用差示扫描量热仪、热重分析仪和X-射线衍射仪研究绿豆淀粉、木薯淀粉、甘薯淀粉和马铃薯淀粉对HCl/KOH法制备的淀粉-脂肪酸包合物糊化和热分解性质、玻璃化转变温度(T_g)、结晶结构等的影响。研究表明,淀粉与脂肪酸复合后晶型变为V型。在薯类淀粉-硬脂酸包合物中,马铃薯淀粉-硬脂酸包合物的糊化温度、T_g和热分解稳定性最高,木薯淀粉-硬脂酸包合物的糊化温度、T_g和热分解稳定性最低。在薯类淀粉-油酸包合物中,木薯淀粉-油酸包合物的糊化焓值(?H)最高,热分解稳定性最小;甘薯淀粉-油酸包合物的?H最低,热分解稳定性最大。比较马铃薯淀粉和绿豆淀粉,马铃薯淀粉-硬脂酸包合物的糊化温度、热分解稳定性高于绿豆淀粉-硬脂酸包合物;马铃薯淀粉-油酸包合物的?H和T_g高于绿豆淀粉-油酸包合物。     

Effects of Malting on Phase Transition Behaviour of Starch in Barley Cultivars with Varying Amylose Content

The effect of malting on the phase transition behaviour of starch in barley cultivars with varying amylose content was studied using differential scanning calorimetry (DSC). A slight elevation in the melting transition temperature of amylopectin of malt starch and a pronounced decrease in gelatinisation enthalpy for both malt flour and starch were observed for all samples. Evidence was provided from the calorimetric data and the ¹³C CP/MAS NMR spectra that starch-lipid interactions in the form of complexes are enhanced as a result of malting. There was also a large reduction in the melting transition temperature of the amylose-lipid complexes of malt flours, presumably due to partial degradation of amylose in malt, whereas the transition enthalpies of the complexes increased for both malt flours and starches. The DSC transition characteristics of the three good malting barley cultivars grown in different locations and of their respective malts showed that environmental conditions during starch synthesis have a great influence on starch granule organization, and thereby affect the thermal stability of amylopectin crystallites.     

Reaction of Starch and Cellulose with Products of Thermal Decomposition of Mono- and Disaccharides

D(—)-Fructose, dextrose and sucrose were thermally decomposed in the presence of native and pregelatinized corn starch, cellulose as well as its mixtures with native corn starch. Several products were obtained in which reactive intermediates thermally generated from lowmolecular saccharides were involved. When starch either was not gelatinized or it could not gelatinize on reaction, the preference for the formation of a physical mixture of caramel with starch and starchsugar complexes was observed. Otherwise products of substitution of starch with reactive intermediates and inclusion complexes were formed. Cellulose appeared to be more reactive. It was grafted to starch by reactive intermediates thermally generated from dextrose.     

Complexation of starch and phenolic compounds during food processing and impacts on the release of phenolic compounds

Phenolic compounds can form complexes with starch during food processing, which can modulate the release of phenolic compounds in the gastrointestinal tract and regulate the bioaccessibility of phenolic compounds. The starch–phenolic complexation is determined by the structure of starch, phenolic compounds, and the food processing conditions. In this review, the complexation between starch and phenolic compounds during (hydro)thermal and nonthermal processing is reviewed. A hypothesis on the complexation kinetics is developed to elucidate the mechanism of complexation between starch and phenolic compounds considering the reaction time and the processing conditions. The subsequent effects of complexation on the physicochemical properties of starch, including gelatinization, retrogradation, and digestion, are critically articulated. Further, the release of phenolic substances and the bioaccessibility of different types of starch–phenolics complexes are discussed. The review emphasizes that the processing-induced structural changes of starch are the major determinant modulating the extent and manner of complexation with phenolic compounds. The controlled release of complexes formed between phenolic compounds and starch in the digestive tracts can modify the functionality of starch-based foods and, thus, can be used for both the modulation of glycemic response and the targeted delivery of phenolic compounds.     

淀粉/聚胺复合物纸张增强机理初探

研究了淀粉/聚胺复合物、阳离子淀粉及原淀粉在纸浆上的吸附类型,测定了淀粉/聚胺混合糊液及单一组分的黏度,探讨了淀粉/聚胺复合物在不同浆种纸张中的作用效果。结果表明,淀粉与聚胺形成了复合物,该复合物对再生浆的作用效果与阳离子淀粉相当,具有明显的增强作用。淀粉/聚胺复合物用量为1.5%时,可使纸板的裂断长增加22.6%,纤维留着增加率提高了6.8%。淀粉/聚胺复合物在纸浆纤维上的吸附为化学吸附和物理吸附共同作用的结果,与阳离子淀粉的吸附相似。     

Formation of Supramolecular Structures of Aroma Compounds with Polysaccharides of Corn Starch Cryotextures

The binding absorption of individual alcohols, ketones, alkyl acetates and their mixtures — used as aroma compounds — from aqueous solutions by corn starch cryotextures was studied by capillary gas chromatography at different starting concentrations of the odourants (1—25 mmol/L). The amount of compound sorbed by the cryotextures increases with concentration of this compound in the initial sol and increasing length of the alkyl chain in the corresponding compound. Linear equations describing the concentration dependence were proposed. The presence of octanol in the mixture increases the binding of hexanol as compared to hexanol alone. The methods of scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy, differential scanning microcalorimetry (DSC) and scanning tunneling microscopy (STM) were used for estimation of the microstructure of sols, and cryotextures, and for the determination of supramolecular complex formation in the systems odourant/cryotexture and odourant/sol. It was shown that waxy corn cryotextures do not form supramolecular complexes with aroma compounds.     

Effect of proteins on the formation of starch–lipid complexes during extrusion cooking of wheat flour with the addition of oleic acid

The formation of starch–lipid complexes plays an important role in extruded products. The effect of gluten proteins on thermal conditions at which the starch–lipid complexes formed during extrusion cooking of wheat flour with the addition of oleic acid was evaluated, considering wheat starch as a reference. The presence of gluten proteins in wheat flour extrudates brought about a reduction of the formation of starch–lipid complexes compared to blend of wheat starch and oleic acid extruded at the same operating conditions (melting enthalpy: 0.4 vs. 1.6 kJ kg^?1). Moreover, the lubricant effect of oleic acid observed during extrusion of wheat starch (low values of specific mechanical energy and residence time) was not found during extrusion of wheat flour with addition of oleic acid because of the interaction between gluten proteins and oleic acid. This research points out the importance of proteins on biopolymer modifications and their effect on extrudate quality.