Effects of wilting and mechanical conditioning on proteolysis in sainfoin (Onobrychis viciifolia Scop) wilted herbage and silage

Ensiling legumes allows conservation of high‐quality forage. However, severe protein degradation occurs during ensiling of legumes. A field study was carried out in 1999 on sainfoin (Onobrychis viciifolia Scop) to investigate the effects of wilting and mechanical conditioning on proteolysis in wilted herbage and silage. The herbage was cut with both a rubber roll conditioning machine (C) and with a mower without conditioner (U). It was wilted in the field to three dry matter (DM) levels (220, 330 and 440 g kg^?1) and ensiled in laboratory glass silos. The herbages and the silages were analysed for ensilability characteristics, fermentation quality and nitrogen fractions. During wilting the non‐protein nitrogen (NPN) values increased (p < 0.05) in both U and C treatment. The free amino acid (free AA) values increased (p < 0.05) from 2.4 to 12.9 and from 2.4 to 7.2 mol kg^?1 total nitrogen, in the U and C treatments, respectively. Low wilted silages (DM content <320 g kg^?1) underwent butyric acid fermentation and extensive proteolysis in both treatments, with lower (p < 0.05) NPN and free AA values in the C treatment. Mechanical conditioning may limit protein breakdown and catabolism of some essential amino acids by reducing the field wilting time in both sainfoin wilted herbage and silage. Copyright © 2004 Society of Chemical Industry     

Assessment of the effect of condensed (acacia and quebracho) and hydrolysable (chestnut and valonea) tannins on rumen fermentation and methane production in vitro

BACKGROUND: Tannins added to animal diets may have a positive effect on energy and protein utilisation in the rumen. The objective of this study was to examine the impact of different sources and concentrations (20, 50, 100, 150 and 200 g kg^?1 dry matter (DM)) of condensed (acacia and quebracho) and hydrolysable (chestnut and valonea) tannins on rumen microbial fermentation in vitro. The experiment also included a negative control with no tannins (control) and a positive control with monensin (10 mg L^?1). RESULTS: In vitro gas production and total volatile fatty acid (VFA) concentration decreased as tannin concentration increased. Addition of acacia, chestnut or valonea tannins at ≥ 50 g kg^?1 or quebracho tannins at ≥ 100 g kg^?1 resulted in a decrease (up to 40%) in methane (CH₄) production compared with the control. Valonea tannins were the only tannin source that reduced (?11%) CH₄ production at 50 g kg^?1 without affecting VFA concentration. Tannin treatments reduced ammonia (NH₃) and branched‐chain VFA concentrations, indicating a reduction in ruminal protein degradation. Monensin reduced CH₄ production (?37%) and NH₃ concentration (?20%) without affecting total VFA concentration. CONCLUSION: Supplying acacia, chestnut or valonea tannins at 50 g kg^?1 has the potential to reduce CH₄ production and ruminal protein degradation with minimum detrimental effects on efficiency of ruminal fermentation. Copyright © 2012 Crown in the right of Canada. Published by John Wiley & Sons, Ltd     

Changes in the nitrogen fraction of sainfoin (Onobrychis viciaefolia) during growth

Sainfoin was harvested at four stages of increasing maturity. Samples were analysed for total N, true protein N, non-protein N, nitrate and amino acids. Variations in the concentrations of these nitrogenous fractions throughout the growing period of plant are described.     

Degradation of condensed tannins by rumen microbes exposed to quebracho tannins (QT) in rumen simulation technique (RUSITEC) and effects of QT on fermentative processes in the RUSITEC

In an earlier study it was observed that the rumen microbes from cattle which had never consumed tannin-containing diets do not have enzymes for degrading condensed tannins. In this study, rumen microbes were exposed to small amounts of quebracho tannins for 8 days using a rumen simulation technique (RUSITEC). The levels maintained in the RUSITEC were 0.1, 0.2 and 0.4 mg of the spray-dried quebracho powder (SDQT) per ml of the medium. After 8 days of tannin exposure, the liquor containing ‘exposed/adapted’ microbes from RUSITEC was incubated for 40 h without and with purified tannins of quebracho and Dichostachys cinerea leaves in in vitro gas method. There was no degradation of condensed tannins. The enzymes for degradation of condensed tannins were not induced in rumen microbes by exposure to different concentrations of tannins for 8 days in the RUSITEC. In the RUSITEC, SDQT significantly reduced the number of total protozoa, entodiniomorphs and holotrichs; effect was higher on holotrichs. There was no significant change in the levels of short chain fatty acid but the molar proportion of propionate was significantly higher and of butyrate significantly lower at 0.4 mg SDQT ml^?1. Significantly lower levels of ammonia in the medium was also observed on injection of tannins. Microbial mass production, calculated using ¹⁵N incorporation, was similar at 0.1 and 0.2 mg SDQT ml^?1 but significantly lower (13%) at 0.4 mg SDQT ml^?1. The dry matter digestibility of the feed (80% hay and 20% barley) was not significantly affected by SDQT.     

The content and distribution of condensed tannins in different species of the genus sorghum (Sorghum Moench) and their effect on seed protein electrophoresis

BACKGROUND: The interaction between condensed tannins (CTs) and seed protein in varieties of sorghum interferes with protein extraction and the separation by electrophoresis, so electrophoresis can not be used widely for determining seed purity and identifying a variety. The objective of this research was to classify the effect of CTs on the extraction of seed storage proteins and on their analysis by SDS–PAGE, and to search for a promising solution to reduce the negative effect of CTs in sorghum. RESULTS: The vanillin–HCl test confirmed that CTs were localised mainly in the glumes of grain sorghum, but distributed in every fraction of sudangrass. Samples with high CT content did not produce any bands in the gel after electrophoresis. Removal of the glumes and pericarp/testa prevented the influence of CTs on electrophoresis for grain sorghum but had little effect for sudangrass. Adding tannin/catechin to the protein extraction of sorghum kernel decreased the number of bands in the gel. Adding polyvinylpyrrolidine to the protein extraction of sudangrass increased the bands. CONCLUSION: Tannin–protein interactions are responsible for the absence of bands in varieties with high CT content. For grain sorghum, decortication can prevent the influence. Adding polyvinylpyrrolidine during the extraction of seed protein could solve the problem of tannin–protein interactions for varieties of sudangrass. Copyright © 2009 Society of Chemical Industry     

Complexes of the condensed tannins of sainfoin (Onobrychis viciifolia scop.) with fraction 1 leaf protein and with submaxillary mucoprotein,and their reversal by polyethylene glycol and pH

In vitro studies were made to determine the nature of complexes formed between the condensed tannins (i.e. pro-anthocyanidins or flavolans) of sainfoin (Onobrychis viciifolia) and either the major soluble dietary protein, Fraction 1 protein, of green leaves, or bovine salivary mucoprotein. Fraction 1 protein, uniformly labelled with ¹⁴C, formed only insoluble complexes with these tannins. Bovine salivary mucoprotein produced insoluble complexes only at temperatures below 25°C. Fraction 1 protein complexes were stable between pH 3.5 and pH 7.0. At pHs below 3.0 greater than 90% of the protein was solubilised in the presence of PEG but at pH 8.0 only 30% of the protein was released from the complex. In vivo experiments with sheep fed sainfoin, confirmed the stability of the tannin-Fraction 1 complexes in the rumen (pH 6.5) and break-up of the complexes in anterior duodenal samples (pH 2.5) as shown by the extractability of condensed tannin from the complex. The significance of these results with respect to (a) bloat in cattle, (b) nitrogen metabolism of ruminants, is discussed. Polyethylene-glycol, mol.wt. 4000 (PEG) exchanged with protein in the complex releasing protein into solution. The effectiveness of PEG was dependent on the amount of tannin in the complex and the age of the complex at the time of addition of PEG. The results explain the observation that PEG is unsuitable as a marker for rumen volume determination when animals are fed herbage that contains condensed tannins. A method for determining any deleterious effects of tannins on nitrogen metabolism by ruminants, is suggested.     

Effect of drying conditions on tannin,fibre and lignin levels in mature oak (Quercus incana) leaves

Oak (Quercus incana Roxb) leaves are rich in tannins and produce adverse effects when fed to livestock. The effects of shade and sun drying and oven drying at 60°C and 90°C for different lengths of time (24 to 72 h) on total phenolics, condensed tannins, protein precipitation capacity, degree of polymerisation, specific activity (protein bound per unit tannins), fibre-linked proanthocyanidins, acid and neutral detergent fibres and lignin levels in mature oak leaves were studied. Removal/inactivation of tannins was not observed on wilting or drying under several conditions. Similarly the drying conditions had no effect on fibre composition. The adverse effects on feeding fresh or dried oak leaves are expected to be of similar magnitude.     

Effect of condensed tannins prepared from several forages on the in vitro precipitation of ribulose-1,5-bisphosphate carboxylase (Rubisco) protein and its digestion by trypsin (EC 2.4.21.4) and chymotrypsin (EC 2.4.21.1)

A series of in vitro experiments was undertaken to determine the extent to which Sephadex LH-20 treated extracts from a range of temperate forages precipitated ribulose-1,5-bisphosphate carboxylase (Rubisco) and affected the enzymatic hydrolysis of Rubisco protein by trypsin and chymotrypsin at a range of pH values. Rubisco was chosen because it represents the principal dietary protein for ruminants fed fresh forages. Condensed tannins (CT) or proanthocyanidins (PA) are routinely purified by chromatography using Sephadex LH-20 as a matrix. However, these extracts contained non-CT phenolics together with PA so the term ‘CT extract’ was preferred to ‘PA’ to describe the extracts. The in vitro precipitation of Rubisco provided a means to compare the reactivity of the CT extracts. The amount of CT extract required to precipitate all the Rubisco in 10 μg of total soluble leaf protein from white clover (Trifolium repens) when this protein was incubated with CT extracts of Lotus corniculatus, L pedunculatus and sainfoin (Onobrychis viciifolia) was similar, with between 25 and 50 μg of extract required. The CT extract of sulla (Hedysarum coronarium) also precipitated all the Rubisco, however this only occurred with 50 μg of the extract. The CT extract of dock (Rumex obtusifolius) precipitated all the Rubisco when 5 μg of extract or greater was incubated with total soluble leaf protein. However, the differences between the reactivity of all these CT extracts at a range of pH values appeared to be small. Condensed tannin extracts of L corniculatus and L pedunculatus partially inhibited the hydrolysis of Rubisco by trypsin and chymotrypsin to a similar extent, but the extent of the inhibition was affected by pH. The inhibition was greater at pH 6·0 than 7·0, whilst at pH 8·0, CT extracts had little or no affect on trypsin and chymotrypsin. It was concluded that, although the precipitation of Rubisco provided an ideal method for comparing CT extracts, reactivity alone was unlikely to account for the differences in nutritive value that occur with forages containing CT. © 1998 SCI.     

Drying method and origin of standard affect condensed tannin (CT) concentrations in perennial herbaceous legumes using simplified butanol‐HCl CT analysis

BACKGROUND: Several factors affect condensed tannin (CT) levels in plants and accuracy of the butanol‐HCl assay for total CT. Six native, perennial, herbaceous legumes from Texas were harvested at three stages of growth over a growing season; young vegetation, initial flowering, and late season. The samples were subjected to oven‐drying and freeze‐drying and analyzed for extractable (ECT), protein‐bound (PBCT), and fiber‐bound (FBCT) CT using a butanol‐HCl procedure, comparing several types of purified CT as standards. RESULTS: There was a wide range of CT concentration in the legumes, but little change in ECT and total (TCT) tannin concentrations over the growing season. Oven‐drying decreased (P < 0.05) ECT and increased (P < 0.05) PBCT and FBCT concentrations compared with freeze‐drying, but both methods ranked the forages similarly throughout the growing season relative to TCT. Quebracho tannin as a standard increased CT values for the forages compared with purified legume CT standards, but all standards ranked the forages similarly relative to tannin concentration. Modifications to the procedure increased speed and ease of using the CT analysis method. CONCLUSION: Quantitative CT values have limited value except to allow a relative ranking of forages. Selection of appropriate standards is important in providing realistic CT values. Improvements in the total (extractable + bound) CT analysis method will allow wider use of this procedure. Although ECT and TCT values changed little in native legumes over a growing season, biological activity and potential nutritional/medicinal benefits of CT in these plants needs further evaluation. Copyright © 2008 Society of Chemical Industry     

香蕉单宁的提取、结构及功能研究进展

单宁作为植物多酚家族的一员,具有抗氧化、抗肿瘤和抗炎症等生理活性,被广泛应用于食品、医药和制革等行业中。香蕉是“世界四大水果”之一,被证明含有丰富的单宁,但鲜有关于香蕉单宁近年来研究进展的总结。因此,本文对香蕉单宁的提取、结构及功能研究进展进行系统性综述。目前,关于香蕉单宁提取工艺的研究主要围绕溶剂提取法、超声波辅助提取法、微波辅助提取法和酶辅助提取法展开,化学结构研究包括对其分子质量分布、聚合度范围、主要化学组成、结构单元及其连接方式的阐明,而功能活性研究则集中在评价香蕉单宁的抗氧化、抗菌、降血脂、降血糖、降低农药对机体毒性、结合金属离子和吸收紫外线等方面的作用。最后,对香蕉单宁今后的研究方向趋势提出展望,以期为扩大其在食品行业中的应用提供一定的理论指导。     

Organic matter digestibility of poplar (Populus) and willow (Salix) forage trees and its in vitro prediction

Cuttings from poplar (Populus) and willow (Salix) trees are used increasingly as supplementary feed for livestock in summer‐dry and drought‐prone regions of New Zealand. The present experiment aimed to measure in vivo organic matter digestibility and digestibility of organic matter in the dry matter in tree fodder and investigated whether the in vitro system of Roughan and Holland can be used to predict in vivo organic matter digestibility and digestibility of organic matter in the dry matter in poplar and willow tree fodder, which contains high concentrations of secondary compounds, including condensed tannin. In vivo work showed that the digestibility of tree fodder declined from late spring to autumn (p < 0.05) and that this decline was much smaller than the decline in digestibility of grass‐based pastures in New Zealand over the same time period. Mean metabolizable energy concentrations and digestibilities were generally higher for willow than for poplar. The in vitro enzymatic system of Roughan and Holland can be used to predict in vivo digestibility of tree fodder. A standard curve using in vivo values determined with animals fed tree fodder would be preferable, owing to the very different chemical compositions of pasture and tree fodder, particularly the greater concentration of secondary compounds in willow and poplar. However, the accuracy and the range of prediction need to be improved. Willow and poplar had similar ME concentrations to high‐quality lucerne hay; willow cuttings also had similar ME and CT concentration to vegetative Lotus corniculatus, a high‐quality forage legume. Copyright © 2005 Society of Chemical Industry     

Oral administration of apple condensed tannins delays rheumatoid arthritis development in mice via downregulation of T helper 17 (Th17) cell responses

Apples are known to contain high concentrations of phenolic compounds such as condensed tannins. Consumption of condensed tannins has been reported to reduce the risk of many types of chronic diseases including allergies. However, their therapeutic effectiveness and potential in treating autoimmune disease remain controversial. Here, the effect of oral administration of apple condensed tannins (ACT) prepared from apples (Malus pumila cv. Fuji) on bovine type II collagen (CII)‐induced arthritis in DBA1/J mice, a well‐established murine model of human rheumatoid arthritis (RA), was evaluated. As compared to the control (without ACT administration) group, RA development was delayed and a significant reduction in the RA clinical score was observed in the ACT‐administered group. Using cultured splenocytes isolated from CII‐immunized mice, ACT‐administration was shown to decrease the CII‐induced increases in IL‐17 expression and production in vitro. We propose that downregulation of T helper (Th) 17 cells is responsible for the ACT‐induced RA suppression.     

保健食品标准中重(装)量差异指标的分析及应用

近年来, 保健食品注册和备案技术指引要求保健食品制剂制订重量差异或装量差异指标, 如片剂等剂型应制订重量差异指标, 胶囊剂等剂型应制订装量差异指标, 以替代原先对包装食品通用的净含量与负偏差指标。在执行过程中, 检测机构众多检验结果显示有不少生产企业可能未能完全理解重量差异和装量差指标的具体分析算法和应用细节要求, 导致抽检结果与生产企业出厂检验结果不一致的情况。本文着重对重量差异和装量差异测定方法的质控目的、限度设定、计算与判定方法等进行详细解读, 以帮助相关企业更好地理解重量差异和装量差异的指标特性和分析应用要点, 阐明重量差异和装量差异指标与包装食品通用的净含量与负偏差指标的不同, 使规范制订保健食品标准并正确执行分析检验。     

Yield and composition of cell wall residues isolated from various feedstuffs used for non-ruminant farm animals

The contents of cell wall residue were measured in 14 common feedstuffs used for non-ruminant farm animals by utilising a technique involving pronase and α-amylase treatments. Comparison with the contents of neutral detergent fibre (NDF) revealed that the NDF procedure underestimated cell wall contents in the dicotyledonous plant materials. The losses of cell wall material due to the neutral detergent solution were correlated (r=0.931, P<0.01) with the amount of pectic substances present in the cell wall residues of the dicotyledonous plant materials. Cell wall residues were analysed for starch, crude protein, polysaccharides, condensed tannins, sulphuric acid lignin, acetyl bromide lignin, and ash. Condensed tannins in the cell wall residues of sorghum, rapeseed meal and field bean resulted in a large protein contamination (11.3–26.6%) of these residues and to an overestimation of their lignin content. Compositions of polysaccharides are discussed from chemical and nutritonal viewpoints.     

A rapid method for the measurement of Leucaena spp proanthocyanidins by the proanthocyanidin (butanol/HCl) assay

Proanthocyanidin (PA) extraction, sample preparation and proanthocyanidin assay (butanol/HCl) reaction conditions were evaluated for measuring PA in Leucaena spp leaf material. The optimal conditions for extracting PA from leaf tissue are described, with short sequential sonications in 70% aqueous acetone being as efficient as prolonged sequential mechanical agitation. In methanol–based extracts, after back extraction to remove pigments, increasing the water content of the reagent/sample matrix suppressed colour development. The addition of low concentrations of Fe³⁺ to the butanol/HCl reagent enhanced colour yield, but higher Fe³⁺ concentrations suppressed colour development. The presence of ascorbic acid in the sample extract was shown to increase colour development. Varying the reagent: sample extract ratio from 4:1 to 6:1 significantly decreased colour yield, but neither ratio was different from 5:1. Optimum conditions for the PA assay were as follows: a water content of 8%, the omission of Fe³⁺, a reagent: sample extract ratio of 5:1 and the addition of ascorbic acid to the stock PA standard solution to match that contributed by the extract in the final mixture. Sample preparation procedures, using back extraction to remove pigments and non-PA phenolics with diethyl ether and ethyl acetate, respectively, were time-consuming and subject to PA losses. The measurement of PA directly in the 70% aqueous acetone extract eliminated these PA losses, but the PA assay required additional optimisation for direct analysis of crude acetone extracts. In the final optimised procedure, PA was extracted by sequential sonication with 70% aqueous acetone containing 5·26 mM sodium metabisulphite as the antioxidant. These extracts were directly analysed by the butanol/HCl reaction using a reagent: sample extract ratio of 5:1, the omission of Fe³⁺ from the butanol/HCl reagent and the addition of sodium metabisulphite to match that contributed by the extract. This produced consistent linear calibration curves over the range 25–1000 μg PA with an average recovery of 101%. © 1998 Society of Chemical Industry.     

Bioactive composition and sensory evaluation of blended jambolan (Syzygium cumini) and sugarcane alcoholic fermented beverages

The consumption of wine has increased considerably in recent years, which has aroused consumer interest in the consumption of alternative wines produced from various fruits. This study evaluates polyphenolic composition, identifies bioactive compounds and assays the total antioxidant capacity of four different formulations of jambolan (Syzygium cumini) and sugarcane fermented beverages (100:0, 70:30, 50:50 and 30:70), as well as their physical and chemical characteristics and also the sensory profile of the beverages. Significant levels of different phenolic compounds were found in the fermented alcoholic beverages. Beverages with higher jambolan content had the greatest content of phenolic compounds. The product produced with 100% jambolan presented 2.99 g gallic acid equivalents per litre of phenolic compounds, 0.67 g Cy3Glu L^?1 of anthocyanins, 0.92 g tannic acid equivalents per litre of tannins and a DPPH free radical scavenging capacity of 85.24%. The phenolic compounds found in higher amounts in the beverages were caffeic, chlorogenic and gallic acid. Treatments elaborated with 100, 70 and 50% of jambolan pulp received the best overall feedback from consumers. The results suggest that jambolan fruit (currently not consumed fresh or used in other ways) could serve as a source of bioactive compounds and therefore be of interest to the food industry. Copyright © 2016 The Institute of Brewing & Distilling