Comparative study of carbohydrates in the two major species of jute (Corchorus capsularis and Corchorus olitorius

Unretted and retted bark and stem of Corchorus olitorius L and retted stem of C capsularis L, two species of jute, were analysed for ash, lignin, low molecular weight carbohydrates and polysaccharides. The results are compared with those from C capsularis published earlier. The unretted bark and stem of C olitorius contained less low molecular weight carbohydrates than the corresponding fractions of C capsularis. C olitorius bark contained less cellulose and more hemicellulose than C capsularis, particularly after retting. Xylans isolated from the retted fibre and stem of C olitorius were found to have a similar composition to those from C capsularis.     

Phenolic acids in the jute plant (corchorus capsularis)

The bark and the stem of unretted jute plant (Corchorus capsularis) were found to contain various free, glycosidic and ester-linked phenolic acids. From an 80% aqueous ethanol extract, p-coumaric, ferulic, caffeic, vanillic and p-hydroxybenzoic acids were identified and quantified. p-Coumaric acid, the major component, and β-sitosterol were isolated and characterised.     

Analysis of carbohydrates in the jute plant (Corchorus capsularis)

Jute plants (Corchorus capsularis) were fractionated into bark and stick. Jute fibre was produced from the bark by retting in water. Polysaccharides and lignin (estimated as Klason lignin) were the major constituents of the three jute fractions. Glucose, fructose, sucrose, six low-molecular weight sugar alcohols (glycerol, erythritol, threitol, rhamnitol, arabinitol, and mannitol), and two inositols (myo-inositol and scyllitol) were identified and quantified in the bark; all these compounds, except rhamnitol were also measured in the stick. Cellulose, xylans and pectins were major polysaccharide constituents in the three jute fractions. During fibre production by retting, extractives and pectic polysaccharides were solubilised or degraded, producing a fibre material enriched in cellulose and xylans.     

Phenolic acids from malt are efficient acetylcholinesterase and butyrylcholinesterase inhibitors

Anticholinesterase activities of mashes produced using wheat (‘Wheat Pale’) or barley malts (‘Pilsner’, ‘Pale Ale’, ‘Munich Light’, ‘Carahell’ or ‘Carared’) were studied by spectrophotometric method. The highest inhibition of acetylcholinesterase and butyrylcholinesterase was observed at 52 °C and/or 64 °C, followed by a decrease or stabilization of the activity at 72 °C. Changes in the total phenolics content in the test mashes were correlated with changes in the acetylcholinesterase and/or butyrylcholinesterase activities. Phenolic acids were singled out from phenolic compounds for more detailed studies owing to their simplicity and structural similarity to well‐known cholinesterase inhibitors. The main phenolic acids in the test malts were ferulic, gallic, p‐coumaric and vanillic acids followed by chlorogenic, caffeic, syringic, p‐OH‐benzoic, sinapic and protocatechuic acids. The anticholinesterase activities of the phenolic acids were studied using model standard solutions at concentrations similar to the maximal content of these compounds in the test mashes. Among the phenolic acids, p‐coumaric acid had the largest share in the anticholinesterase activity, even though it was present in the test mashes at a significantly lower concentration (~0.38 mm L^?1) than ferulic acid (~1.00 mm L^?1). Sinapic acid and p‐OH‐benzoic acid (0.03 and 0.01 mm L^?1, respectively) were equally efficient inhibitors as ferulic acid at ~1.00 mm L^?1. This preliminary study should be extended to other phenolic compounds from malt (wort) in the near future. Copyright © 2012 The Institute of Brewing & Distilling     

Carbohydrate composition and content of organic acids in fresh and stored apples

The contents of low‐molecular‐weight carbohydrates (LMWC; sorbitol, glucose, fructose and sucrose), starch, dietary fibre and organic acids were determined in seven apple cultivars at the start and end of the consumption interval. The cultivars included were Summered, Aroma, Ingrid Marie, Cox Orange, Mutzu, Belle de Boskoop and Jonagold. The total content of LMWC ranged between 615 and 716 g kg⁻¹ dry matter (DM). The dominating sugar was fructose, corresponding to on average 57% (range 48–62%) of the total LMWC. However, in Cox Orange the sucrose content was considerably higher and the fructose and sucrose contents constituted approximately 46% each. Total dietary fibre content was similar in the cultivars (total dietary fibre 160 ± 20 g kg⁻¹ DM), except for Belle de Boskoop which had a higher content (203 g kg⁻¹ DM). Mutzu had a lower proportion of soluble fibre (27% of total dietary fibre) compared with the others (mean 32%). The organic acid content was on average 80 ± 4 g kg⁻¹ DM, except for two of the cultivars (Summered and Belle de Boskoop) which had a higher content (105 ± 6 g kg⁻¹ DM). Interestingly, the organic acid content was only slightly reduced upon storage in the case of Belle de Boskoop, whereas there was a substantial decrease in all the other cultivars (p < 0.001). Sucrose (p < 0.01) and starch (p < 0.05) contents decreased in all cultivars following storage, whereas sorbitol (p < 0.05) and total dietary fibre (p < 0.05) contents increased. It is concluded that the observed differences in composition are of such magnitude that they may affect both nutritional and sensory properties. © 2000 Society of Chemical Industry     

Phenolic compounds,lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)

Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p‐coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59 mg kg^?1 fresh weight, while naringenin levels were lower than 12.55 mg kg^?1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32 mg kg^?1 fresh weight, followed by caffeic acid, while p‐coumaric and ferulic acids showed similar concentrations lower than 5 mg kg^?1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50 mg kg^?1 fresh weight), while the concentration in the other varieties was between 50 and 30 mg kg^?1, with the exception of Liso (less than 20 mg kg^?1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry     

Effect of Cooking on Isoflavones,Phenolic Acids,and Antioxidant Activity in Sprouts of Prosoy Soybean (Glycine max)

Soy sprouts possess health benefits and is required to be cooked before consumption. The effects of cooking on the phenolic components and antioxidant properties of soy sprouts with different germination days were investigated. A food‐grade cultivar Prosoy with a high protein content was germinated for 1, 2, 3, 5, and 7 d and cooked till palatable for 20, 20, 5, 5, and 7 min, respectively. Total phenolic content (TPC), total flavonoids content (TFC), condensed tannins content (CTC), individual phenolic acids, isoflavones, DPPH, ferric‐reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) of raw and cooked sprouts were measured. Cooking caused significant losses in phenolic content and antioxidant activities, and maximum loss was on day 3 > 5 > 7, including TPC (32%, 23%, and 15%), TFC (50%, 44%, and 20%), CTC (73%, 47%, and 12%), DPPH (31%, 15%, and 5%), FRAP (34%, 25%, and 1%), and ORAC (34%, 22%, 32%), respectively. Cooking caused significant losses in most individual phenolic acid, benzoic group, cinnamic group, total phenolic composition, individual isoflavones, and total isoflavones. The losses of phenolic acids such as gallic, protocatechuic, hydroxybenzoic, syringic, chlorogenic, or sinapic acids during cooking were not compensated by the increases in trihydroxybenzoic, vanillic or coumaric acids on certain days of germination. Cooking caused minimal changes in phenolic acid composition of day 1 and 2 sprouts compared to 3, 5, and 7 d sprouts.     

An improved gas chromatography-based approach for characterisation of fatty acids in fresh basil seed oil

An improved gas chromatography-based analytical method for the simultaneous separation of seventy-two fatty acids was developed. Twenty-six types of trans fatty acids and conjugated linoleic acids were separated and identified with this method, especially trans C18 isomers. This method was confirmed to be high throughput and have high sensitivity and a low detection limit. It was successfully applied to separate and identify fatty acids in fresh basil seed oil. The linolenic acid content (51.67 g/100 g) was highest in basil seed oil, followed by linoleic acid (20.16 g/100 g) and oleic acid (12.70 g/100 g). These unsaturated fatty acids in fresh basil seed oil were transformed into trans fatty acids, conjugated linoleic acids and saturated fatty acids after heating to a certain temperature for an adequate duration, and the formation mechanisms were characterised.     

苹果酒中酚酸、黄烷-3-醇的检测

以小国光(Ralls)和富士(Fuji)及其所酿制的新鲜苹果酒为试验材料,采用反相高效液相色谱法测定分析苹果原汁、发酵中酒样和苹果成品酒中11种酚酸、5种黄烷-3-醇的含量。结果表明:苹果和苹果酒中存在4种酚酸(原儿茶酸、绿原酸、咖啡酸、对-香豆酸)、2种黄烷-3-醇(儿茶素和表儿茶素);不同品种的苹果原汁和苹果成品酒中酚类物质的含量都存在显著差异。其中,小国光苹果和小国光苹果酒中的酚类物质总含量较高;对于每个品种,绿原酸都是最主要的酚酸类物质,含量最高的黄烷-3-醇类物质都是表儿茶素。随着发酵过程的进行,苹果酒中酚类物质的含量有不同程度的增加。其增加趋势为S型曲线,即先平缓再较快再平缓。     

半自动连续发酵残次鲜红枣醋及其有机酸分析

以残次鲜枣为原料,通过破碎制浆、酒精发酵、半自动连续醋酸发酵等工序加工枣醋,探讨残次鲜枣生产枣醋的可行性。将洗净的残次鲜枣,加1.5倍水打浆后接种0.1%的酿酒活性干酵母进行常温酒精发酵(72h),得到枣酒液酒精度8.07%Vol;枣酒液接种10%的活化醋酸菌菌种,经过60h可完成第一批醋酸发酵;采用分割留种发酵法进行10批次半自动连续醋酸发酵制备红枣醋,发酵周期为30h,各批枣醋平均酸度为4.81g/100 mL。采用反相高效液相色谱法(RP-HPLC)从残次鲜枣果醋中检出10种有机酸,主要为醋酸、乳酸和苹果酸,其有机酸组成和含量与优质鲜枣果醋无明显差异。以残次鲜枣为原料通过半自动连续醋酸发酵法能高效生产红枣醋,品质与优质鲜枣果醋相当,表明该方法可用于枣产区转化残次鲜枣资源生产果醋。     

七种养殖淡水鱼类肌肉营养组成及对比研究

本文采用国家标准方法分析了我国常见的七种淡水养殖鱼类肌肉中的水分、灰分、蛋白质、粗脂肪、氨基酸、脂肪酸等营养成分。七种鱼的水分含量范围在74.7%⁸0.5%;草鱼肌肉中蛋白质最高为20.5%;乌鳢肌肉中灰分含量最高为1.4%;鲫鱼的粗脂肪含量最高11.9%。七种淡水鱼氨基酸总量在15.4%¹6.8%（鲜重计）;它们的必需氨基酸占总氨基酸的比值（WEAA/WTAA）在40.45%⁴3.5%之间,必需氨基酸与非必需氨基酸的比值（WEAA/WNEAA）为在86.8%⁹4.2%之间,它们的第一限制性氨基酸都是Met+Cys,其中鳜鱼的EEAI值最高,达85.8,最理想的均衡补充氨基酸的营养食品。在七种鱼中鲫鱼肌肉中脂肪酸总量最高达3.79%;其EPA和DHA的含量也达到最高,分别为0.01%和0.16%;鳊鱼肌肉中亚油酸:亚麻酸值达到了6.3,最接近中国居民膳食营养素参考摄入量均衡比例。本文为常见淡水经济鱼种的养殖和加工利用提供基础资料。      

Lignification of switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii) plant parts during maturation and its effect on fibre degradability

Five cultivars of switchgrass (Panicum virgatum L) and four cultivars of big bluestem (Andropogon gerardii Vitman) were harvested at vegetative, boot and heading stages of maturity. Leaf and stem fractions were analysed for detergent fibre composition and 48-h ruminal in-vitro degradability, ester- and ether-linked non-core lignin phenolic acids, and core lignin composition. Big bluestem leaves contained more neutral detergent fibre than switchgrass, but general composition of the fibre did not differ. Stem fibre of switchgrass had relatively lower levels of cellulose and lignin at the vegetative stage than observed in big bluestem. Esterified and etherified p-coumaric and ferulic acid concentrations were generally higher in switchgrass plant parts. Yield of nitrobenzene oxidation products from core lignin was greater for switchgrass leaves, but very little difference in composition was noted. Leaf tissue contained lower concentrations of all lignin components than stems. Maturation resulted in increased total lignification, but all components did not respond in the same manner. Variation for all measures of lignification seemed to be as great within species as between the grass species. Degradability of fibre declined with maturation. The only species difference was that switchgrass fibre was more degradable at the vegetative stage. Relationships between lignification and fibre degradability were in agreement with some, but not all, previously reported relationships. Concentration of core lignin was only a significant predictor of fibre degradability when the relationship was examined across maturity stages. Within a stage of maturity, lignin composition was more closely related to fibre degradability than was concentration. However, the best predictors of fibre digestibility differed among species, plant part and maturity.     

苦荞中酚酸和原花色素的分析测定

采用了反相液相色谱法 (RP HPLC) ,结合二极管阵列检测器 (DAD)分析 ,测定了苦荞籽粒各部分 (壳、麸皮、外层粉、内层粉 )的酚酸和原花色素。测定结果表明 ,苦荞中的酚酸种类主要是苯甲酸类———原儿茶酸和对羟基苯甲酸 ;酚酸总量在 94.61～ 1745 .3 3mg/kg。原花色素含量在 0 .0 3 %～ 5 .0 3 %。     

植物食品原料中酚酸的生物合成与调控及其生物活性研究进展

酚酸是高等植物中广泛分布的含有酚羟基和羧基的一类次生代谢产物,主要通过酯键及醚键与细胞壁结构 组分以结合态存在于植物食品原料中,具有抗氧化、抗菌和抗癌等多种生物活性。植物食品原料中的酚类物质已成 为当前食品领域研究热点之一。通过一系列生物调控技术能够在植物食品原料中富集酚酸,从而提高其营养价值。 本文综述了植物食品原料中酚酸的类型与结构、生物合成与调控及其生物活性,并对此进行了展望。     

Distribution of bound and free phenolic acids in oranges (Citrus sinensis) and Grapefruits (Citrus paradisi)

Free phenolic acids may be the precursors for vinyl phenols and off-flavours formed in citrus products during storage. Quantitative determination of free and bound phenolic acids in fruit parts of grapefruit (Citrus paradisi Macfadyen) and oranges (Citrus sinensis (L) Osbeck) was performed by extraction with ethyl acetate, silica gel column chromatography and HPLC analyses of samples before and after alkaline hydrolysis. The content of free and bound phenolic acids was further determined in juice derived from fruit harvested early, mid and late in season. As found previously for ferulic acid, phenolic acids occur mainly in bound forms in grapefruits and oranges. In both fruits the peels contained the major portion of cinnamic acids compared with the endocarp, and the flavedo was richer in hydroxycinnamic acids than the albedo. In most cases, hydroxycinnamic acid content was in the following order: ferulic acid>sinapic acid>coumaric acid>caffeic acid. Results showed that the content of bound cinnamic acids was unchanged or slightly elevated from early to late season. However, the content of free acids was reduced during that period.     

温州蜜柑、椪柑采后酚类物质及抗氧化活性比较研究

通过研究温州蜜蜂柑、椪柑两个常见柑橘品种贮藏期间类黄酮、酚酸类物质及抗氧化活性的变化规律,评价其采后的营养品质。结果表明：贮藏60d后温州蜜柑较好地保持了抗坏血酸含量,而椪柑损失较大。类黄酮类物质较稳定,温州蜜柑中黄烷酮含量贮藏后有所增加,椪柑中则呈缓慢下降趋势,2种柑橘中酚酸类物质贮藏后都有所增加。总酚含量在贮藏前期呈下降趋势,贮藏后期温州蜜柑中总酚含量增加而在椪柑中进一步下降。抗氧化能力与抗坏血酸的变化趋势类似。与椪柑相比,贮藏期间温州蜜柑能更好地保持果实的营养品质及酚类物质,从而保持较高的抗氧化活性。