Free amino acid amounts in raw cocoas from different origins

Raw cocoa is the processed and traded form of the cocoa seed. Fresh seeds undergo fermentation and a drying process before they are prepared for transport and shipping. Depending on the local situation in the producer region the seeds are collected from big estates and are fermented and dried in big lots or they originate from small farmer's crop trees. In the subsequent transport and trading chain raw cocoas may be mixed and stored before they finally are sold and brought to the consumer countries. Local or regional variations in cocoa plant material, fermentation procedures and drying processes finally result in a typical traded good with respect to the amino acids, which form an important part of the flavour precursors. These free amino acids and their composition result from the fermentation procedure of fresh seeds. In the course of the fermentation specific cleavage of cocoa storage proteins delivers the amino acid patterns. In this study the variation of free amino acid amount and distribution of 108 commercially fermented and traded cocoa samples and two Theobroma grandiflorum (Willd. ex Spreng.) K. Schum samples were determined. This examination showed clearly, that content and distribution of free amino acids in raw cocoa from different origins vary greatly (5–25 mg g⁻¹ fatfree dry matter), in some cases country and even region-specific differences were apparent. It is important to notice typical, region-specific variations in the amounts and compositions of free amino acids.     

Assessment of film-forming potential and properties of protein and polysaccharide-based biopolymer films

This study assessed the film‐forming abilities of six types of proteins, as well as six types of polysaccharides at various concentrations (proteins: 0–16%; polysaccharides: 0–4%) and heating temperatures (60–80 °C). Biopolymer films evaluated included: sodium caseinate (SC), whey protein isolate (WPI), gelatine (G); caboxymethyl cellulose (CMC), sodium alginate (SA) and potato starch (PS). Screening trials showed that optimal film‐forming conditions were achieved using SC and G (4% and 8%), WPI (8% and 12%), PS, CMC (2% and 3%) or SA (1% and 1.5%) solutions heated to 80 °C in combination with 50% (w/w) glycerol. Films manufactured from 1.5% SA, 8% G and 3% CMC had the highest tensile strength (24.88 MPa); flexibility (89.69%)/tear strength (0.30 N) and puncture resistance (22.66 N), respectively. SC, WPI and G‐based films were more resistant to solvent than SA, CMC and PS. Film permeability to water vapour and oxygen decreased in the order: 12% WPI to 1% SA and 12% WPI to 1% SA. All films tested were impermeable to oil.     

桔梗多糖活性炭脱色工艺研究

研究桔梗多糖的活性炭脱色工艺。以脱色率和多糖保留率为指标,在单因素的基础上,采用正交试验对活性炭脱色工艺进行优化。结果表明,活性炭脱色的最佳条件为:在60℃下,调节pH为6.0,加入体积分数为0.5%的活性炭,脱色20 min,脱色率为80.47%,多糖保留率为83.51%。该脱色工艺对桔梗多糖可获得较高的脱色率和多糖保留率。     

Structural,morphological and rheological characterisation of bovine serum albumin–cress seed gum complex coacervate

The interactions between the bovine serum albumin (BSA) and cress seed gum (CSG) were investigated by structural, morphological and rheological characterisation as a function of pH level (7.0–2.0) and biopolymers’ concentrations (BSA, 0.1%, 0.5% and 1%, w/w and CSG, 0.01%, 0.05% and 0.1%, w/w). The results showed that turbidity, zeta potential and coacervate yield values had correlations with the initial number of biopolymers, which are influenced by the level of the positive and negative charges of BSA and CSG. Furthermore, the optimal complexation conditions in terms of pH, CSG-BSA content and yield were 3.5%, 0.05–0.1% and 61.17% respectively. Rheological properties revealed the formation of a weakly gel-like structure with a shear-thinning behaviour. X-ray diffraction (XRD) and scanning electron microscopy (SEM) authenticated an amorphous and branch-like network structure in the coacervate phase respectively. These results reflect that CSG-BSA complex coacervate could be an appropriate biopolymer carrier for susceptible and bioactive compounds.     

Free and bound flavour components of Amazonian fruits: 3-glycosidically bound components of cupuacu

The total quantity (11.7 mg/kg of pulp) of aglycones released by enzymatic hydrolysis of the glycosidic extract indicates a significant aroma potential for cupuacu. Among the 47 aglycones identified, 24 are not present in the free volatile fraction, among them, 4-methylguaiacol, 4-propylguaiacol, 2,6-dimethyl-octa-1,7-dien-3,6-diol, 2,6-dimethyl-oct-7-en-1,6-diol, homovanillic acid, 2-methyl-but-3-en-1-ol and acetic acid. The quantitatively most important aglycones are 3-methyl-butan-1-ol, 2-phenylethanol, linalol, (Z)-2,6-dimethyl-octa-2,7-dien-1,6-diol, butan-1-ol and hexan-1-ol. The methylated alditol acetates analysis of monosaccharides released by acid hydrolysis of the heterosidic extract, indicates that glucose is involved in glucosidic and glycosidic structures. Moreover, rhamnopyranose and xylopyranose units, bound in the terminal position, suggest the presence of rutinosides and small amounts of primeverosides. Six glucosides, hexyl, benzyl, 2-phenylethyl, (R) and (S)-linalyl and geranyl β--glucopyranosides, five rutinosides, benzyl, (R) and (S)-linalyl, -terpineyl and 2-phenylethyl rutinosides and 3-methyl-but-2-enyl vicianoside were identified by GC–EIMS after TFA derivatization of the crude heterosidic fraction. Moreover, four linalol oxides, octyl, 3-methyl-butyl β--glucopyranosides and hexyl, octyl, two linalol oxides and 3-methyl-butyl rutinosides, have been tentatively identified from their TFA mass spectra. Some glucosides are probably substituted by malonyl and unidentified acyl residues.     

桔梗多糖抗氧化特性及对2型糖尿病大鼠降血糖作用

目的：研究桔梗多糖抗氧化性及其对2型糖尿病(T2DM)大鼠降血糖作用。方法：提取并测定桔梗多糖含量及桔梗多糖对不同自由基的清除能力。采用高脂高糖饲料喂养大鼠6周后,大鼠腹腔注射STZ(30 mg/kg·BW)建立T2DM模型,将其分为正常组、模型组、桔梗多糖高剂量组(400 mg/kg)、桔梗多糖低剂量组(200 mg/kg)、阳性组(二甲双胍200 mg/kg),定期测定大鼠体重及空腹血糖值(FBG);并进行口服糖耐量(OGTT)测试,测定大鼠总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)、丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)和过氧化氢酶(CAT)的变化。结果：桔梗多糖含量为89.65%,在1 000 μg/mL质量浓度下其对DPPH·、ABTS+·、·OH、PTIO的清除能力分别为91.3%,89.7%,83.8%,90.4%。与模型组相比,桔梗多糖能够有效缓解T2DM大鼠体重的下降,显著降低其FBG(P＜0.05),以及显著提高OGTT水平(P＜0.05),经桔梗多糖高剂量治疗后,TC、TG、LDL-C、MDA 水平显著下降,HDL-C、SOD、GSH、CAT水平显著上升(P＜0.05),且所有指标均呈剂量依赖性。结论：桔梗多糖具有较好的抗氧化性,可以通过改善T2DM大鼠脂代谢水平和氧化应激水平从而起到降血糖作用。     

MEASUREMENT OF RESIDUAL CARBOHYDRATE IN BEER

No standardized method exists for the determination of total or individual carbohydrates in beer and this could cause difficulties in view of regulatory requirements for labelling. A comparative study of known methods likely to be most suitable for the measurement of total carbohydrate in beer was therefore undertaken. Methods were also examined for estimating other important residual carbohydrates in beer, such as residual fermentable carbohydrates, β-glucan, total fructose and fructosans, and total pentose and pentosans. The beers analysed covered a wide range of carbohydrate levels and, as expected, the different methods gave different values for the carbohydrate content of the same beer. We consider that the colorimetric anthrone-sulphuric acid procedure (Yadav's version) is to be preferred for estimating the total residual carbohydrate content of beer. It is less prone to interference, relatively simple, rapid and gives more accurate results than acid or enzymic hydrolysis in combination with reductometric procedures. The within-laboratory coefficient of variation is 1.68%.     

桔梗多糖脱蛋白方法的研究

目的：探讨桔梗多糖脱蛋白的方法。方法：以蛋白去除率和多糖损失率为指标,比较Sevag法、三氯乙酸-正丁醇法、正丁醇法、AB-8大孔吸附树脂法去除桔梗多糖中蛋白质的效果。结果：AB-8大孔吸附树脂脱蛋白的效果最好,蛋白去除率为90.1%,多糖损失率为17.4%。结论：AB-8大孔吸附树脂蛋白去除率高,且多糖损失率低,是一种有效的脱蛋白方法。     

桔梗多糖的制备工艺及生物活性研究进展

桔梗为桔梗科多年生植物[Platycodon grandiflorum (Jacq.) A.DC.]的根,具有悠久的食用和药用历史,是药食同源大宗品种之一,具有重要研究价值。桔梗根鲜品在中国东北和华北地区常被腌制为咸菜,市场需求量大,其干燥根则在中医临床常用于治疗咳嗽痰多,胸闷不畅,咽痛音哑,肺痈吐脓等病症。现有研究表明,桔梗中含有丰富的功能性多糖,在免疫调节、抗炎、止咳等生物活性方面发挥着至关重要的作用,具有重要的研究和开发前景。然而,当前国内外主要针对其结构与生物活性进行研究,尚无关于桔梗多糖的系统文献综述。该文通过梳理国内外有关桔梗多糖提取、分离纯化以及生物活性等方面的研究文献,对桔梗多糖的最新研究进展进行了系统归纳和总结,为日后桔梗多糖类成分的研究和深度开发利用提供参考。     

2021版《中华医学会肿瘤学分会肺癌临床诊疗指南》非小细胞肺癌诊疗更新专家解读

目的：探究不同提取工艺桔梗多糖（PGP）的理化性质,不同提取工艺所得的PGP对奥沙利铂（OXA）体内分布的影响。方法：本研究采用了热水提取（HW）、醋酸辅助提取（CA）、氨水辅助提取（KA）、超声辅助提取（UA）制备桔梗多糖,通过红外光谱、紫外光谱、凝胶色谱、高效液相色谱等方法测定多糖的理化性质;建立OXA电感耦合等离子体-质谱（ICP-MS）体内分析方法,考察OXA单用组、OXA联用PGP-HW组、OXA联用PGP-CA组、OXA联用PGP-KA组、OXA联用PGP-UA组SD大鼠体内奥沙利铂分布的变化;使用Western Blot方法来测定肺组织中Oct-2和Pg-P蛋白的表达水平,考察PGP改变OXA体内分布的机制。结果：四种桔梗多糖在理化性质方面呈现出明显的区别。其中,PGP-KA的得率最高;四种桔梗多糖红外图谱均具备典型的多糖特征吸收峰;在分子量组成上,它们主要由7 kDa和3790 kDa两个分子量构成,但各自的分子量分布比例有所不同。此外,这四种桔梗多糖都含有甘露糖（Man）、鼠李糖（Rha）、半乳糖醛酸（GalA）、葡萄糖（Glu）、半乳糖（Gal）以及阿拉伯糖（Ara）,但比例存在差异;四种多糖粒径主要集中在300 nm左右,且具有良好的溶液稳定性;与OXA单用组比,OXA联用PGP-CA组、OXA联用PGP-KA组分别增加肺组织OXA含量为36.93%和35.12%,且OXA联用PGP-KA组显著（P<0.05）增加Oct-2蛋白表达水平,而P-g-P蛋白表达水平无显著差异。结论：不同的提取工艺获得的PGP的理化性质不同,其中OXA联用PGP-CA组和OXA联用PGP-KA组能显著增加OXA在肺组织分布水平,其机制可能与增加肺组织中Oct-2的表达量有关。

     

响应曲面法优化桔梗多糖提取条件研究

以桔梗根为实验材料,基于单因素(提取时间、提取温度、物料比、pH值和NaCl浓度)试验结果,确定桔梗多糖提取主要因素,分别为物料比、提取时间和提取温度。通过中心组合试验设计,得到最佳提取条件为物料比34.43,提取时间89.83min,提取温度52.47℃,桔梗多糖提取率为39.87%。通过验证实验,此模型确认有效。     

MEASUREMENT OF CARBOHYDRATES IN WORT AND BEER—A REVIEW

Methods are reviewed for measuring total wort and beer carbohydrate and carbohydrate fractions, such as dextrins, oligosaccharides, fermentable sugars, β-glucans, total fructose and fructosans, pentose and pentosans. The methods are conveniently classified under the following headings: reductometry, colorimetry, enzymic procedures, automated analyses, paper and column chromatography, thin layer chromatography, gas liquid chromatography and high performance liquid chromatography. Techniques involving chromatography are particularly useful for separating and estimating individual sugars.     

Effect of inclusion of soluble and insoluble fibres into extruded breakfast cereal products made with reverse screw configuration

Five dietary fibre rich ingredients were used at 5%, 10% and 15% replacement levels in a white flour cereal base to produce an extruded cereal product. The inclusion of the dietary fibres into the flour bases had no significant effect on the expansion ratio of the products. However, the bulk density of the extruded products increased with inulin addition. The pasting properties of the raw flour and fibre base as well as the extruded products were altered with the incorporation of dietary fibre, with guar gum enriched products showing elevated peak and final viscosity readings. This appeared to be related to moisture manipulation and hence the regulation of gelatinisation. In vitro starch hydrolysis of the raw bases and the extruded samples illustrated that the extrusion process significantly increased the availability of carbohydrates for digestion. Additionally, the inclusion of dietary fibres in the raw bases significantly reduced the rate and extent of carbohydrate hydrolysis of the extruded products. As such the addition of dietary fibres to extruded products reduced the amount of readily digestible starch components of breakfast products, and increased the amount of slowly digestible carbohydrates.     

CARBOHYDRATE BALANCES AND WORT FERMENTABILITY ESTIMATIONS

Brewery mashing extracts virtually all the malto-saccharides from malt, but slightly less carbohydrate is extracted than can be obtained in the laboratory. Fermentation with the ale yeast NCYC 240 results in complete removal of fermentable sugars except maltotriose which is less than half utilized. The concentration of pentosan, β-glucan and total dextrin fractions does not change significantly during fermentation. However, both β-glucan and pentosan fractions decrease very slightly during fining and filtration. The discrepancy between different values obtained for wort fermentability using a yeast method and using procedures involving the analysis of total and individual sugars is mainly due to the presence of non-carbohydrate material, which must be taken into consideration in the yeast procedure when calculating the gravities of the wort and beer. Good agreement is found between fermentability values obtained using chemical and yeast procedures when this correction is applied.     

打瓜不同部位的可溶性总糖分析与水溶性多糖的自由基清除活性

分别测定了打瓜外皮、内皮、瓤和籽中的蛋白质和可溶性总糖,再提取各部位多糖并测定其自由基清除活性。实验结果表明,在干打瓜外皮、内皮、瓤和籽中蛋白质含量分别为6.65%、1.22%、5.60%和30.04%。在鲜瓜外皮中可溶性糖含量为33.94mg/g,鲜内皮中为29.77mg/g,鲜瓤中为58.94mg/g,干籽中为32.95mg/g。用醇沉法由鲜外皮、内皮、瓤和干籽中所得的提取物中多糖含量分别为33.29%、28.05%、93.39%和15.77%,鲜外皮、内皮、瓤和干籽中多糖含量分别为0.17%、0.016%、0.19%和1.59%。外皮、内皮、瓤和籽的水溶醇沉提取物对羟基自由基、超氧阴离子和DPPH自由基具有一定的清除能力。其中打瓜外皮、内皮、瓤和籽提取物对羟基自由基清除,以及打瓜内皮提取物对DPPH的清除能力好于同浓度维生素C。      

The carbohydrate composition of cotyledons and hulls of cultivars of Lupinus angustifolius from Western Australia

The hulls and cotyledons from three Western Australian cultivars (Gungurru, Yorrel and Danja) of Lupinus angustifolius, all of low alkaloid content, were analysed separately for their carbohydrate content and composition. Only minor differences in composition between these three cultivars were observed. More notably, the cotyledons of all the cultivars contained levels of non-starch polysaccharides (NSP), ranging from 290 to 310 g kg^?1 dry weight considerably higher than had been measured previously in cultivars of this species. Galactose, arabinose and uronic acid residues accounted for approximately 67%, 13% and 10%, respectively, of the cotyledon NSP. Although only a small proportion of the cotyledon NSP is soluble, a much larger proportion could be extracted with hot EDTA treatment. The oligosaccharide content of the cotyledons ranged from 74 to 80 g kg^?1 dry weight. Cotyledons had very low contents of cellulose, lignin and starch. Hulls consisted predominantly of NSP, with values ranging from 856 to 891 g kg^?1 dry weight. Glucose, xylose, uronic acids and arabinose were the principal sugar residues present reflecting the compositions of the major constituent polysaccharides, cellulose, hemicelluloses and pectins. Only low levels of lignin were measured in hulls. Cotyledon NSP and hulls from these cultivars may have considerable value as sources of dietary fibre in the human diet.