超声提取辣木叶黄酮优化及其抗氧化活性

采用响应面分析法对辣木叶黄酮的超声提取工艺进行优化。以乙醇浓度、料液比、提取时间、提取温度为考察因素,总黄酮得率和氧自由基吸收能力（ORAC）值为响应值,进行四因素三水平的Box-Behnken实验设计,最优条件:乙醇浓度70%,料液比1∶27（g/m L）,提取时间46 min,提取温度50℃,在此条件下,总黄酮得率为（48.93±0.44）mg RE/g,ORAC值为（2747.17±301.51）μmol TE/g,与预测值（49.23 mg RE/g,2853.99μmol TE/g）的误差为0.6%和3.7%。采用聚酰胺树脂对辣木叶黄酮粗提物进行纯化,纯化后黄酮含量为65.89%,ORAC值为（5923.48±228.65）μmol TE/g,且纯化前后均表现出较强的DPPH和ABTS自由基清除能力,其EC50值分别为0.45、0.10 g/m L和0.26、0.05 mg/m L。结果表明超声提取是一种高效的提取辣木叶黄酮方法;聚酰胺树脂可有效提高辣木叶提取物中的黄酮含量并显著提高其抗氧化性。      

辣木叶多糖的分离纯化及其体外降糖活性研究

目的研究辣木叶多糖的制备、单糖组成以及体外降糖活性。方法采用水提醇沉、Sevage法、大孔树脂-阴阳离子交换树脂联用技术得到较高纯度辣木叶粗多糖,再进一步通过二乙氨基乙基纤维素和葡聚糖凝胶柱层析分离得到2个主要多糖组分(MOs-2-a、MOs-2-b),并通过水解衍生化对其单糖组成进行分析。此外,采用HepG2细胞建立胰岛素抵抗模型,以细胞葡萄糖消耗量为指标,考察辣木叶多糖的降糖作用。结果本文采用的制备工艺可以得到较高纯度的辣木叶粗多糖(纯度为73.10%),辣木叶多糖主要由甘露糖、鼠李糖、葡萄糖及半乳糖组成,其中各单糖摩尔比为0.49:3.65:0.63:1.27。与模型组相比,辣木叶多糖组分MOs-2-a、MOs-2-b均能显著增加胰岛素抵抗HepG2细胞的葡萄糖消耗量(P0.05)。结论辣木叶多糖MOs-2-a、MOs-2-b具有良好的降糖效果,本文可以为辣木叶多糖作为功能食品发展的提供科学依据。     

Effects of variety on chemical composition,in situ nutrient disappearance and in vitro gas production of spineless cacti

This study determined the chemical composition, in situ ruminal nutrient disappearance and in vitro gas production kinetics of three cactus varieties grown in northeastern Brazil. The varieties were Gigante, IPA‐20 and Miúda. Results of the chemical analysis showed no significant differences in ash, ether extract, crude protein (CP) and neutral detergent fibre (NDF) between the cactus varieties. However, acid detergent fibre was highest (P < 0.05) for IPA‐20, intermediate (P < 0.05) for Gigante, and lowest (P < 0.05) for Miúda. Fractionation of carbohydrate and true protein based on rates of ruminal degradation indicated that the main carbohydrate component was the rapidly degradable fraction, whereas the main true protein component was the intermediately degradable fraction. No differences in carbohydrate or protein fractions were observed between the cactus varieties. Results of the in situ experiment showed no differences in ruminal dry matter (DM, average 803 g kg^?1 of DM), CP (900 g kg^?1 of CP) and NDF (611 g kg^?1 of NDF) disappearance between the three cactus varieties after 48 h of ruminal incubation. Potential gas production at the end of 48 h of incubation was higher (P < 0.05) for Gigante than for the Miúda or IPA‐20 variety. However, rate of gas production and lag time in gas production were similar for the three cactus varieties at 6.8% h^?1 and 0.6 h respectively. Our results showed little or no differences in chemical composition or ruminal nutrient degradabilities between the three cactus varieties. Copyright © 2003 Society of Chemical Industry     

In vitro degradability of mature and immature leaves of tropical forage legumes differing in condensed tannin and non‐starch polysaccharide content and composition

A study was designed to examine the relationships between protein, condensed tannin and cell wall carbohydrate content and composition and the nutritional quality of seven tropical legumes (Desmodium ovalifolium, Flemingia macrophylla, Leucaena leucocephala, L pallida, L macrophylla, Calliandra calothyrsus and Clitoria fairchildiana). Among the legume species studied, D ovalifolium showed the lowest concentration of nitrogen, while L leucocephala showed the highest. Fibre (NDF) content was lowest in C calothyrsus, L Leucocephala and L pallida and highest in L macrophylla, which had no measurable condensed tannins. The highest tannin concentration was found in C calothyrsus. Total non‐structural polysaccharides (NSP) varied among legumes species (lowest in C calothyrsus and highest in D ovalifolium), and glucose and uronic acids were the most abundant carbohydrate constituents in all legumes. Total NSP losses were lowest in F macrophylla and highest in L leucocephala and L pallida. Gas accumulation and acetate and propionate levels were 50% less with F macrophylla and D ovalifolium as compared with L leucocephala. The highest levels of branched‐chain fatty acids were observed with non‐tanniniferous legumes, and negative concentrations were observed with some of the legumes with high tannin content (D ovalifolium and F macrophylla). Linear regression analysis showed that the presence of condensed tannins was more related to a reduction of the initial rate of gas production (0–48 h) than to the final amount of gas produced or the extent (144 h) of dry matter degradation, which could be due to differences in tannin chemistry. Consequently, more attention should be given in the future to elucidating the impact of tannin structure on the nutritional quality of tropical forage legumes. Copyright © 2003 Society of Chemical Industry     

Compositional and nutritional attributes of seeds from the multiple purpose tree Moringa oleifera Lamarck

Moringa oleifera Lam is a multipurpose tree cultivated to use as a vegetable, for spice, for cooking and cosmetic oil and as a medicinal plant. Owing to the use of its seeds as food and as a clarifying agent of turbid water some nutritional and antinutritional characteristics were studied. The mature seeds contained 332.5 g crude protein, 412.0 g crude fat, 211.2 g carbohydrate and 44.3 g ash per kg dry matter. The essential amino acid profile compared with the FAO/WHO/UNU scoring pattern requirements for different age groups showed deficiency of lysine, threonine and valine. The content of methionine + cysteine (43.6 g kg⁻¹ protein), however, was exceptionally higher and close to that of human milk, chicken egg and cow's milk. The seed extract agglutinated rabbit erythrocytes but did not show trypsin inhibitor and urease activities. Feeding rats with a diet containing the seed meal showed loss of appetite, impaired growth, lower NPU and enlargement of stomach, small intestine, caecum + colon, liver, pancreas, kidneys, heart and lungs and atrophy of thymus and spleen in comparison with rats fed on an egg‐white diet. The results indicated that consumption of M oleifera raw mature seeds should be viewed with some caution until suitable processing methods are developed to abolish the yet unknown adverse factors. © 1999 Society of Chemical Industry     

气相色谱法分析不同产地辣木叶中植物甾醇的含量

目的研究西双版纳、韶关、安哥拉、印度和云南辣木叶中菜油甾醇、β谷甾醇和豆甾醇的含量差异。方法样品经50%氢氧化钾皂化后,用乙醚:正己烷(1:1,V:V)萃取游离甾醇并将溶剂蒸干,用N,N-二甲基甲酰胺:六甲基二硅氨烷:三甲基氯硅烷(8:2:1,V:V:V)将游离甾醇硅烷化,然后进行气相色谱分析,并分析各地辣木叶中菜油甾醇、豆甾醇和β谷甾醇含量。结果β谷甾醇在韶关辣木叶中含量为20 mg/100 g左右,在西双版纳辣木叶中含量为40 mg/100 g,在安哥拉、印度和云南辣木叶中含量为30 mg/100 g左右;菜油甾醇在韶关辣木叶中含量为5~7 mg/100 g,在印度辣木叶中含量为8 mg/100 g,在西双版纳、安哥拉和云南辣木叶中均大于10mg/100 g;豆甾醇在各个辣木叶中含量为2~12 mg/100 g。结论西双版纳、云南、安哥拉、印度辣木叶中菜油甾醇、β谷甾醇含量明显高于韶关辣木叶,豆甾醇含量没有明显的地域差异。     

Potential nutritive value and tannin bioassay of selected Acacia species from Kenya

Six Acacia forage species–A. brevispica, A. elatior, A. mellifera, A. nilotica, A. senegal and A. seyal—were analysed for their chemical composition, including phenolics and rumen fermentation characteristics. In vitro gas production technique was used to study the rumen fermentation characteristics and the effect of tannins present in the browse forages on in vitro fermentation by including polyethylene glycol (PEG‐6000) in the incubation. The forages had high crude protein content (145.7–270.1 g kg^?1 DM) and low to moderate content of neutral detergent fibre (220.2–442.8 g kg^?1 DM). The forages had variable content of total extractable phenolics ranging from 18.4 to 384.2 g kg^?1 DM and total extractable tannins ranging from 7.1 to 364.8 g kg^?1 DM (tannic acid equivalent). Fractionation of the condensed tannin flavonoids showed that the delphinidin/cyanidin ratio ranged from not detected:100 to 71:29. The gas production potential ranged from 28.4 to 40.8 mL gas 0.2 g^?1 DM. The rate of gas production was highest in A. elatior and lowest in A. nilotica. Addition of PEG‐6000 increased gas production significantly (P < 0.05) in all species except A. mellifera. PEG‐6000 addition did not have any significant effect on in vitro true dry matter and organic matter degradability but decreased the partitioning factor in all the species. Gas production and degradability parameters correlated positively with the CP content and negatively with the fibre and phenolics contents. Based on chemical composition, gas production and degradability, the forages have high potential nutritive value, especially as supplements to low‐quality feeds in the tropics and particularly during the dry season. However, the presence of tannins in terms of high levels and biological antinutritive activity may limit the nutritive potential of some of the forages, such as A. seyal and A. nilotica. Copyright © 2007 Society of Chemical Industry     

辣木叶抗氧化活性研究及活性成分含量测定

目的:确定辣木叶抗氧化有效部位,建立HPLC测定辣木叶中新绿原酸和异槲皮苷含量的方法。方法:采用体外方法评价辣木叶提取物四个部位石油醚萃取物、乙酸乙酯萃取物、总奎宁酸和总黄酮的抗氧化活性;采用HPLC,选择Sepax Sapphire C₁8（250 mm×4.6 mm,5μm）色谱柱,流动相为乙腈-0.05%磷酸溶液梯度洗脱,流速为1 mL/min,检测波长330 nm,柱温30℃。结果:以异槲皮苷为代表的黄酮类成分和新绿原酸等奎宁酸类成分清除能力最强,二者浓度大于800μg/m L时,对DPPH清除率达80%以上,且对DPPH和羟自由基清除率均高于石油醚和乙酸乙酯萃取物;新绿原酸和异槲皮苷在检测范围内线性关系良好,平均加样回收率分别为98.84%、98.70%,RSD均小于3.0%。结论:辣木叶抗氧化有效部位为总奎宁酸和总黄酮;该方法简便可靠,可作为辣木叶中新绿原酸和异槲皮苷的定量分析方法。      

Unique interrelationships between fiber composition,water-soluble carbohydrates,and in vitro gas production for fall-grown oat forages

Sixty samples of ‘ForagePlus’ oat were selected from a previous plot study for analysis of in vitro gas production (IVGP) on the basis of 2 factors: (1) high (n = 29) or low (n = 31) neutral detergent fiber (NDF; 62.7 ± 2.61 and 45.1 ± 3.91%, respectively); and (2) the range of water-soluble carbohydrates (WSC) within the high- and low-NDF groups. For the WSC selection factor, concentrations ranged from 4.7 to 13.4% (mean = 7.9 ± 2.06%) and from 3.5 to 19.4% (mean = 9.7 ± 4.57%) within high- and low-NDF forages, respectively. Our objectives were to assess the relationships between IVGP and various agronomic or nutritional characteristics for high- and low-NDF fall-oat forages. Cumulative IVGP was fitted to a single-pool nonlinear regression model: Y = MAX × (1 – e ^{[–K× (t – lag)]}), where Y = cumulative gas produced (mL), MAX = maximum cumulative gas produced with infinite incubation time (mL), K = rate constant, t = incubation time (h), and lag = discrete lag time (h). Generally, cumulative IVGP after 12, 24, 36, or 48 h within high-NDF fall-oat forages was negatively correlated with NDF, hemicellulose, lignin, and ash, but positively correlated with WSC, nonfiber carbohydrate (NFC), and total digestible nutrients (TDN). For low-NDF fall-grown oat forages, IVGP was positively correlated with growth stage, canopy height, WSC, NFC, and TDN; negative correlations were observed with ash and crude protein (CP) but not generally with fiber components. These responses were also reflected in multiple regression analysis for high- and low-NDF forages. After 12, 24, or 36 h of incubation, cumulative IVGP within high-NDF fall-oat forages was explained by complex regression equations utilizing (lignin:NDF)², lignin:NDF, hemicellulose, lignin, and TDN² as independent variables (R² ≥ 0.43). Within low-NDF fall-grown oat forages, cumulative IVGP at these incubation intervals was explained by positive linear relationships with NFC that also exhibited high coefficients of determination (R² ≥ 0.75). Gas production was accelerated at early incubation times within low-NDF forages, specifically in response to large pools of WSC that were most likely to be present as forages approached boot stage by late-fall.     

Assessment of nutritive value of cereal and legume straws based on chemical composition and in vitro digestibility

The nutritive value of 17 straws was determined on the basis of their chemical composition, in vitro dry matter (DM) digestibility and rumen fermentation kinetics (from gas production curves measured in vitro). Five roughages were from the cereal species Avena sativa (oat), Hordeum vulgare (barley), Secale cereale (rye), Triticum aestivum (wheat) and Zea mays (maize stover). The other 12 samples were legume straws, two samples from each of the species Cicer arietinum (chickpea), Lens culinaris (lentil) and Phaseolus vulgaris (bean) and one sample from each of the species Lathyrus sativus (chickling vetch), Lupinus albus (white lupin), Pisum sativum (field pea), Vicia articulata (one‐flowered vetch), Vicia ervilia (bitter vetch) and Vicia sativa (common vetch). All samples were collected after harvesting from different farms located in León (northwestern Spain). Based on their chemical composition, digestibility and gas production characteristics, species could be clustered into two groups with a significant linkage distance, one for cereal straws that merged at a level of similarity of 80% and the other for legume straws with a degree of similarity of 50%. Species varied widely and significant differences (P < 0.05) were observed between the two groups of straws. Legume straws showed higher crude protein (74 ± 6.1 vs 29 ± 2.2 g kg^?1 DM) and lower fibre (584 ± 18.1 vs 793 ± 27.5 g neutral detergent fibre kg^?1 DM) contents than cereal straws and, consequently, DM digestibility coefficients (0.670 vs 0.609; standard error of difference 0.0054) and metabolisable energy values (7.4 ± 0.15 vs 5.7 ± 0.24 MJ kg^?1 DM) were significantly greater in legume than in cereal straws. Although there were noticeable differences among species within each botanical family, legume straws showed better nutritional quality than cereal straws, indicating that they could be considered promising and interesting sources of roughage for incorporation into ruminant diets. Copyright © 2005 Society of Chemical Industry     

Comparison of sheep and red deer rumen fluids for assessing nutritive value of ruminant feedstuffs

Four forages (alfalfa hay, barley straw, maize silage and beet pulp), four cereal grains (barley, maize, sorghum and wheat) and four shrubs (Calluna vulgaris, Erica australis, Cytisus cantabricus and Genista occidentalis) were incubated using rumen fluids from sheep and red deer, to examine differences in in vitro fermentation rates and ruminal parameters. For the forages and cereal grains, results suggest few differences between species in parameters related to gas production, rates of fermentation, organic matter disappearance and extent of degradation. Deer showed slightly better results for shrubs than sheep did. Disappearance of neutral detergent fibre was generally greater when the rumen fluid was derived from red deer (P < 0.05). On the other hand, ammonia‐N concentration and total volatile fatty acids (VFAs) were higher in sheep (P < 0.05). Molar proportions of the major VFAs showed significant differences (P < 0.05) associated with the species of the inoculum donor and suggest that fermentation pathways might have been more efficient in red deer. The estimated amount of methane was higher in sheep, regardless of the substrate incubated (P < 0.001). The results indicate that although the sheep could be valid as a model to assess the nutritive value of good quality feedstuffs for red deer, it would fail to offer reliable information on non‐conventional, low‐quality feeds such as shrubs. Copyright © 2005 Society of Chemical Industry     

Comparison of in vitro degradation of temperate forages using the gas production and filter bag techniques

BACKGROUND: Two of the most promising in vitro techniques for dynamic forage evaluation are the gas production (GP) and filter bag (FB) techniques. To improve our understanding of how these techniques describe the dynamic degradation of forages, 20 temperate forage samples were analysed by each method at different time points during a 96 h incubation period. The results of the recordings were fitted to a biphasic Michaelis–Menten model describing the degradation of rapidly and slowly degrading forage fractions. RESULTS: GP and disappearance from the FB measurements were correlated at all time points from 6 to 96 h (R² = 0.27–0.74), except at the 24 h incubation point. When GP was transformed into organic matter degradation (OMD), there was an even stronger correlation (R² = 0.54–0.75) between the techniques at all intervals. Comparison of the parameters from the Michaelis–Menten model resulted in correlations (R² = 0.83) between the sizes of the estimated forage fractions, but not between parameter determining the rates of their degradation. CONCLUSIONS: Both the GP and FB techniques have the potential to estimate the degradation of individual feed fractions in forages. Further studies in which the in vitro parameters are evaluated against livestock data, are needed to confirm the findings of this study, however. Copyright © 2007 Society of Chemical Industry     

Feeding value,in vitro digestibility and in vitro gas production of different by‐products for ruminant nutrition

Nine by‐products used in animal nutrition were examined for their nutritive value by determining the chemical composition (crude protein, crude fat (ether extract), neutral detergent fibre, acid detergent fibre, lignin), in vitro organic matter digestibility and rumen fermentation kinetics (from gas production curves measured in vitro). The by‐products studied were giant pumpkin, red pepper, stem broccoli, brewer's grain, fresh artichoke, scalded artichoke, lemon peel, orange peel and melon. The nutritive value was very variable, depending on the by‐product and on the process applied to the material during industrial processing. In vitro gas production was measured for 500 mg dry matter in quadruplicate at 39 °C after 6, 12, 24, 36, 48 and 72 h of incubation and fitted to single‐pool exponential equations. The fermentation kinetics indicated that brewer's grain was the only by‐product which fitted well with the p = a + b(1 ? e^?ct) equation model; all other by‐products had a very fast degradation rate and their gas production fitted the equation p = b(1 ? e^?c(t?L)), because in the other exponential model a was negative. © 2002 Society of Chemical Industry     

Difference in in vitro fermentability of four carbohydrates and two diets,using ileal and faecal inocula from unweaned piglets

An experiment was conducted to examine differences in the in vitro fermentability of four carbohydrate‐rich feed ingredients and two weaning piglet diets with and without these ingredients, using both the ileal contents and the faeces of unweaned piglets as inocula. In the first part of the experiment, cumulative gas production was measured over time, using faecal inocula mixed from nine specially raised crossbred piglets (no creep feed or antibiotics) at 3 weeks of age. Inulin, lactulose, unmolassed sugar beet pulp, wheat starch and the two diets were used as substrates and fermented in vitro for 72 h. Gas production was measured as an indicator of the kinetics of fermentation. Fermentation end‐products, including volatile fatty acids and ammonia, and organic matter loss, were also measured. For the fermentations of feed ingredients, samples were also collected for polymerase chain reaction/denaturing gradient gel electrophoresis analyses initially and after the fermentation process, to study changes in the composition of the bacterial community. This procedure was repeated 1 week later, using ileal contents from the same piglets as inoculum. There were significant differences between the inocula, in terms of both overall fermentation characteristics and composition and between the substrates. There was also a significant interaction between inocula and substrates, which suggests that there were potentially important differences in the microbial activity occurring in these two areas of the gastrointestinal tract (GIT). For the two diets, one with and one without addition of these fermentable ingredients, there were significant differences in terms of the kinetics, but less so in terms of the end‐products of fermentation. It was concluded that inocula from both the small and large intestine should be used to obtain a more accurate assessment of potential feed ingredients which will stimulate fermentation in the piglet GIT. Copyright © 2005 Society of Chemical Industry     

Effects of cultivars on ensiling characteristics,chemical composition,and ruminal degradability of pea silage

A study was conducted to determine the effects of cultivar on ensiling characteristics, chemical composition and ruminal nutrient degradability of pea (Pisum sativum L.) silage. The cultivars evaluated were Lenca (L), Carneval (C), and Delta (D). Peas were field-grown and forage was harvested and ensiled in mini-silos for 0, 2, 4, 8, 16, and 70 d. The ensiled forage of all cultivars went through a rapid fermentation with a sharp reduction in pH during the first 2 days of ensiling. Extensive proteolysis took place between 0 and 2 d as indicated by a reduction in true protein and neutral detergent insoluble protein (NDICP) and an increase in nonprotein nitrogen. Chemical analysis of the 70 d silage showed that cultivar L contained higher neutral detergent fiber (NDF) and acid detergent fiber and lower starch levels than C and D. Crude protein was highest for C (20.5% DM), intermediate for D (19.0% DM) and lowest for L (17.9% DM). Distribution of protein fractions showed that L contains lower soluble protein and higher NDICP levels than the other two pea cultivars. However, no difference in acid detergent insoluble protein levels was observed between the three cultivars. Results of the in situ incubation experiment indicated that L had lower ruminal DM (69.2 vs 74.0%) and CP (84.1 vs 90.6%) degradabilities than C or D. However, ruminal degradability of NDF was similar among the three cultivars (average of 32.9%). It was concluded that chemical composition and ruminal nutrient degradability of pea silage are significantly influenced by cultivars.     

Nutritive evaluation of herbage from permanent meadows by near‐infrared reflectance spectroscopy: 1. Prediction of chemical composition and in vitro digestibility

This study was implemented to evaluate the potential of near‐infrared reflectance spectroscopy (NIRS) technology to estimate the chemical composition and in vitro digestibility of botanically complex herbage mixtures characterised, moreover, by a noteworthy variation among samples in the maturity of the forage plants. A total of 107 herbage samples harvested from permanent meadows located in the uplands of León (northwestern Spain) were analysed to determine their chemical composition. In addition, the in vitro digestibility of each herbage sample was measured by two different in vitro procedures using buffered rumen fluid. A Bran + Luebbe InfraAlyzer 500 spectrophotometer was used to obtain the near‐infrared spectra corresponding to each herbage sample. Prediction equations developed for the estimation of the chemical components showed that NIRS technology could predict these parameters accurately, especially the crude protein and neutral detergent fibre contents ( in both cases). In vitro digestibility parameters could also be predicted with an acceptable degree of accuracy using NIRS technology, particularly the in vitro Tilley and Terry organic matter digestibility ( , standard error of prediction (SEP) = 2.165% organic matter) and the in vitro dry matter true digestibility measured according to the Goering and Van Soest procedure ( , SEP = 2.208% dry matter). Copyright © 2005 Society of Chemical Industry