In vitro interaction of polyphenols of coffee pulp and some proteins

The in vitro interaction of pure polyphenols and polyphenol extracts of coffee pulp with pure proteins was studied. The polyphenols used for the assays were tannic acid, chlorogenic acid and catechin, and the proteins were gelatin, casein and bovine serum albumin (BSA). Different pHs and different polyphenol/protein ratios were used in the experiments. Extracts of coffee pulp in methanol, methanol-water (50:50), ammonium hydroxide 3%, and calcium hydroxide 1%, were used. In general, the maximum binding of polyphenol with protein was obtained at a polyphenol/protein ratio of 1/2, at a pH of 5.0. The higher binding percentages were found with the ammonium hydroxide extract and with tannic acid. The lowest binding percentage was obtained with the methanol-water extract. The other extracts presented intermediate binding degrees. The results herein reported demonstrate that the polyphenols of coffee pulp have capacity to bind proteins in vitro at the pHs assayed. This phenomenon may be the cause of the deficient protein utilization when coffee pulp is included in the animals' diet.     

Effects of the treatment of coffee pulp, fresh or ensilaged, with calcium hydroxide, on its nutritive value

This study was carried out to determine the effects of the addition of calcium hydroxide on the chemical composition and nutritive value of fresh or ensilaged coffee pulp. Fresh or ensilaged pulp were mixed with 1, 2 and 3% of calcium hydroxide. The process was carried out during 0 and 16 hr, after which time the treated pulp was sun-dried for 36 hr until moisture content reached 12%. These samples were then analyzed for their proximate chemical composition and for some minerals (Ca, P, Na, K), as well as for caffeine, tannins and chlorogenic and caffeic acids content. Diets were then prepared from these materials, containing 15% protein and 15 or 30% fresh or ensilaged coffee pulp, and offered to weanling rats during six weeks. Information required on weight gain, food conversion, apparent digestibility and toxicity of the diets was recorded. Results of the chemical analysis revealed that the main changes found in both types of pulp as a result of the calcium hydroxide treatment were the following: a decrease in ether extract (from 4.0 to 2.5 g/100 g), crude fiber (from 18.3 to 11.9 g/100 g) and protein content (from 12.3 to 8.6 g/100 g) in an inverse relation to the amount of calcium hydroxide used. The amount of ash increased, fluctuated between 5.5 and 15.4%, depending on the amount of calcium hydroxide used. The latter affected the Ca:P ratio in the diets, where an average ratio of 7.2:1 was found in the control pulp (0% calcium hydroxide) and 59.0:1 in those treated with the highest amount of calcium hydroxide (3%). Regarding the caffeine, tannins and chlorogenic and caffeic acids contents, calcium hydroxide was effective in decreasing only tannins, more so in the fresh than in the ensilaged pulp; the decrease was in direct proportion to the amount of calcium hydroxide added and to the length of the Ca(OH)2 treatment. The results of the biological assays showed that the addition of Ca(OH)2 in either of the two time periods used and at either of the concentrations studied, did not improve the nutritive value of coffee pulp. There was always a better performance in the animals that consumed ensilaged pulp than in those fed fresh pulp. The animals fed 15% coffee pulp either fresh or ensilaged performed better than those consuming 30% coffee pulp.(ABSTRACT TRUNCATED AT 400 WORDS)     

Bleaching of Rice Straw Paper Pulp and Possibilities for Replacement of Sodium Hydroxide by Ammonium Hydroxide During the Extraction Stage

Bleaching of rice straw soda pulp was investigated under various conditions. The rate of the chlorination and hypochlorite reactions were studied; the best properties were attained by shortening the chlorination time to about 20 min. The extraction efficiency of ammonium hydroxide on chlorinated soda pulp was also investigated. The effectiveness of extraction can be deduced from the reduction of the kappa number, cuprammonium viscosity and the brightness obtained after the hypochlorite step. Extraction can be carried out with ammonium hydroxide instead of sodium hydroxide used in the conventional method. The strengths of unbleached and fully bleached pulps were evaluated. The fully bleached ammonium hydroxide extracted pulps were beaten faster and were usually stronger than the corresponding pulps extracted with sodium hydroxide.     

铁观音绿茶茶多酚提取工艺研究

将有机溶剂提取法这一技术应用于提取绿茶的有效成分---茶多酚.采用正交实验法优化茶多酚的最佳提取条件,选择浸提温度、浸提次数、浸取时间和有机溶剂的浓度作为考察因素,以茶多酚的提取率为评价指标,通过单因素试验的考察,每个因素选取4个水平.得出最佳的提取工艺为:温度65℃,洗提次数3次,有机溶剂提取时间35 min,有机溶剂浓度55%.在这种条件下从绿茶中提取的茶多酚的收率为最高.并采用红外波谱法对提取出的产品进行定性分析,检测得出绿茶提取物的主要成分为茶多酚.     

川佛手中多酚提取工艺优化及抗氧化研究

采用超声波法提取川佛手中的多酚。通过单因素试验研究了提取温度、乙醇体积分数、料液比和提取时间等因素对提取效率的影响。在此基础上,进行L9(34)正交试验,确定了多酚的最佳提取工艺参数:提取温度为50℃,乙醇体积分数为60%,料液比为1∶30 g·mL-1,提取时间为1.5 h,最大提取率达到1.95%。以抗坏血酸(VC)为对照,测定川佛手多酚提取物的DPPH·和·OH的清除率,结果表明川佛手多酚具有较强的抗氧化活性。     

Effect of polyphenols of coffee pulp on iron absorption

The effect of the polyphenols of coffee pulp on iron absorption was studied using the method of ligated segments in rats. Optimal conditions to measure iron absorption, were determined using as criteria the concentration of Fe59 and the time that produced the highest value of blood radioactivity. A concentration of 0.4 uCi/dose of Fe59 and a 3-hr period were chosen to measure iron absorption. Experimental groups were formed assigning six rats randomly to each group. Each group was injected with a solution of 59Fe and either with the standard polyphenol solution or with the coffee pulp extract, except the control group which was injected with the Fe59 solution only. The effect of two polyphenol concentrations was also studied. Iron uptake from the duodenum was found to be the best indicator of iron absorption when compared to the sum of iron uptake by the tissues (blood, liver, spleen, kidneys, heart and carcass). Therefore, this indicator was used to interpret the results obtained. Catechin, tannic acid and the coffee pulp extract decreased significantly iron absorption when compared with the control group. The level of polyphenols used in these experiments is similar to the amounts consumed by animals fed coffee pulp at a 10% level. Therefore, we can conclude that the antinutritional effect of coffee pulp polyphenols may be partially due to their capacity to bind iron.     

Optimization of Phenolic Antioxidant Extraction from Wuweizi (Schisandra chinensis) Pulp Using Random-Centroid Optimazation Methodology

The extraction optimization and composition analysis of polyphenols in the fresh pulp of Wuweizi (Schisandra chinensis) have been investigated in this study. The extraction process of polyphenols from Wuweizi pulp was optimized using Random-Centroid Optimization (RCO) methodology. Six factors including liquid and solid ratio, ethanol concentration, pH, temperature, heating time and extraction times, and three extraction targets of polyphenol content, antioxidant activity and extract yield were considered in the RCO program. Three sets of optimum proposed factor values were obtained corresponding to three extraction targets respectively. The set of optimum proposed factor values for polyphenol extraction given was chosen in further experiments as following: liquid and solid ratio (v/w) 8, ethanol 67.3% (v/v), initial pH 1.75, temperature 55 °C for 4 h and extraction repeated for 4 times. The Wuweizi polyphenol extract (WPE) was obtained with a yield of 16.37 mg/g and composition of polyphenols 1.847 mg/g, anthocyanins 0.179 mg/g, sugar 9.573 mg/g and protein 0.327 mg/g. The WPE demonstrated high scavenging activities against DPPH radicals.     

Enhancing the recovery and concentration of polyphenols from camu-camu (Myrciaria dubia H.B.K. McVaugh) by aqueous two-phase flotation and scale-up process

In this study, polyphenols obtained from camu-camu pulp residue were recovered and concentrated from aqueous two-phase flotation (ATPF) by evaluating different operating conditions, such as solvent type, pH, ammonium sulfate concentration, flotation time, air flow, and volumetric ratio. Under optimal conditions, the polyethylene glycol 400/ammonium sulfate ATPF system showed an efficiency of 81.02% and a concentration coefficient two times higher than traditional aqueous two-phase extraction. Experiments were also carried out on a semi-pilot scale, using an apparatus with a 2.5-L working volume. The results showed that the semi-pilot system was comparable to the smaller scale system.     

茶多酚提取工艺影响因素探究

茶多酚是茶叶的主要活性化合物,有效提取茶多酚,实现其综合利用具有十分重要的现实意义。初步探讨浸提次数、提取温度、不同浓度的提取液、不同的反应时间和茶叶的粉碎情况对茶多酚提取结果的影响。结果表明:70℃水浴为最佳提取温度,70%的甲醇水为最佳提取浓度,60min为最佳放置时间。     

从柑橘皮中超声提取橙皮甙

在超声波作用下,用饱和Ca(OH)2水溶液浸提、盐酸酸析,从柑橘汁加工下脚料———柑橘果皮中提取橙皮甙。以精制橙皮甙收率为评价指标,利用正交实验L9(34)筛选最佳工艺条件为:超声提取温度25℃、超声时间30min、饱和Ca(OH)2溶液与柑橘皮质量比4∶1、超声频率25kHz。按优选的最佳工艺实验3次,精制橙皮甙平均收率达2 32%(为常规浸提法的1 61倍),相对标准偏差(RSD)为0 91%(n=3)。     

葡萄籽多酚类物质的盐析萃取

采用乙醇/（NH₄）₂SO₄两相盐析体系,从酿酒副产物葡萄籽中提取多酚、类黄酮和原花青素。实验结果表明,在室温下用组成（质量分数）为30%乙醇/18%（NH₄）₂SO₄的体系提取葡萄籽中多酚、类黄酮以及原花青素,得率分别为64.54、42.45、23.16 mg·g^-1;它们富集于上相乙醇相,萃取回收率分别为97.31%、98.19%、97.92%。室温条件下用2,2-二苯基-1-苦基肼（DPPH）法与2,2'-连氮基-双-（3-乙基苯并二氢噻唑啉-6-磺酸）（ABTS）法测定两相盐析萃取物抗氧化、清除自由基能力,IC₅₀分别为61.85、71.76 mg·L^-1,比传统的热回流提取物具有更强的抗氧化活性。     

栾树叶总多酚的超声波辅助提取工艺及其抗氧化活性

以10g栾树叶粉末为原料,在单因素试验基础上,采用响应面法优化栾树叶总多酚超声波辅助提取工艺,以乙醇体积分数、液料比、提取时间、提取温度、超声波功率为因子,总多酚质量分数、总多酚得率为响应值,得到优化提取条件为乙醇体积分数72%、液料比25:1(mL:g)、提取时间15 min、提取温度60℃、超声波功率200 W以及提取3次。在此条件下,栾树叶粗提物总多酚质量分数为61.26%、总多酚得率为3.41%。抗氧化实验结果表明:栾树叶粗提物清除1,1-二苯代苦味酰基(DPPH)自由基能力显著高于BHT和Vc,IC₅₀值为103.78 mg/L;栾树叶粗提物的铁离子还原能力与BHT相当,明显高于Vc。     

Comparison of solvent systems on extraction,quality characteristics,and volatile compounds of palm kernel oil

Hexane (HEX) and dichloromethane (DCM) have been used to extract oils from various sources due to their expansive solubility and low volatility that ease removal at low temperatures. However, environmental and health concerns make them undesirable solvents. The aim of this study was to evaluate the extraction efficiency and physicochemical characteristics of palm kernel oil (PKO) extracted with the addition of acetone in HEX-acetone (1:1, vol/vol) and DCM-acetone (1:1, vol/vol) mixtures as an alternative to DCM and HEX alone. PKO extracted with co-solvent systems had better quality characteristics compared with single solvent extracts. The oil recovered, free fatty acid content, peroxide value and other quality characteristics, and thermal properties were within the range for PKO, and similar oils as stipulated in standards. Monounsaturated fatty acid content in PKO was up to 70% of which lauric acid was the most abundant (48%–52%). A total of 50 volatile compounds were identified by GC–MS in all the extracts including amide (1), alcohol (1), aldehydes (2), ketones (3), acids (6), esters (6) and hydrocarbons (31) with higher numbers of volatiles in the HEX extracts compared to the DCM extracts. Dodecanoic acid, hexanal, and 2-undecanone were the most abundant acid, aldehyde, and ketone, respectively. Principal component analysis (PCA) differentiated the volatiles identified on the polar and non-polar columns with 88.2% and 8.8%, and 67.3% and 19.6% of the variation accounted for by PC1 and PC2, respectively, with several common volatile components forming a cluster from all the solvents used.     

思茅松树皮中寡聚原花色素提取的初步研究

以甲醇、50%甲醇、70%丙酮及50%丙酮等为溶剂,石油醚为沉淀剂从思茅松树皮中提取了寡聚原花色素。以寡聚原花色素标准品为对照,比较了提取物与标准品的红外光谱,并通过紫外光谱法对提取物中寡聚原花色素的含量进行了测定,结果表明:上述溶剂均可从思茅松树皮中提取寡聚原花色素,提取率分别为1.08%、1.41%、1.78%和2.53%。     

花椒总多酚的超声提取与分离研究

以湘西青花椒为原料,采用超声辅助萃取法提取总多酚,用单因素实验和正交试验考查了丙酮体积分数,料液比,提取温度和提取时间对花椒总多酚提取率的影响.结果表明:以40%丙酮为溶剂,在料液比为1:15(m/V)、60℃温度下超声提取80 min,总多酚提取率为0.5068%.     

Bioactive extracts of orange (Citrus sinensis L. Osbeck) pomace obtained by SFE and low pressure techniques: Mathematical modeling and extract composition

The objective of this study was to obtain orange (Citrus sinensis L. Osbeck) pomace extract using supercritical fluid extraction (SFE) with CO₂ and with CO₂ and co-solvent. In order to evaluate the high pressure method in terms of process yield, extract composition and biological activity, low pressure methods were also applied to obtain orange extracts, such as ultrasound (UE) and soxhlet (SOX), with different organic solvents, and hydrodistillation (HD). The SFE conditions were temperatures of 313.15 K and 323.15 K and pressures from 100 to 300 bar. The SFE kinetics and mathematical modeling of the overall extraction curves (OEC) were also investigated. The antioxidant potential of the extracts was evaluated by the DPPH method, by the Folin-Ciocalteau method and by the β-carotene/linoleic acid bleaching method. The antimicrobial activity of the extracts was also studied. The main compounds identified were l-limonene, palmitic and oleic acids, n-butyl benzenesulfonamide and β-sitosterol.     

Ability of cellulosic materials to initiate graft copolymerization by photo-irradiation

The ability of various kinds of cellulose samples to initiate graft copolymerization of methyl methacrylate by photo-irradiation was examined. Untreated samples (absorbent cotton, sulfite pulp, dissolving pulp, and semichemical pulp), extracted samples (1% sodium hydroxide, methanol, and ethanol-benzene mixture as extraction solvent), oxidized samples (periodic acid, sodium hypochlorite, hydrogen peroxide, and nitrogen dioxide), a reduced sample, an oximated sample, and a ferric ion-adsorbing sample were used for the experiments. It was found that impurities in the sample as well as the oxidized states affect the initiation reaction remarkably. It was also noted that the contribution of these factors was remarkable in an irradiation system with a light of wavelength longer than 300 nm, although in the systems using sensitizers or irradiation with a light of shorter wavelength, initiation took place almost indifferent to the cellulose characteristics.     

Extraction of coal through dilute alkaline hydrolytic treatment at low temperature and atmospheric pressure

Assam coal was extracted with ethylenediamine (EDA) using batch as well as Soxhlet techniques. It was found to be further extractable in EDA after a first extraction step. Stepwise extraction of coal in EDA resulted in 44% extraction. Alkali treatment enhanced the extractability of coal in EDA. Two step (1.5%) aqueous alkali treatment followed at each step by EDA extraction, resulted in 50% extraction of coal. Various solvents were tried in the aqueous alkali treatment of coal. EDA, tetralin, phenol, quinoline, ethanol and butanol were found to give good results. The use of Na₂CO₃ and Ca(OH)₂ along with NaOH in the alkali treatment did not improve the extractability of the coal. Nonaqueous alkali treatment of coal in different solvents also resulted in an enhanced extraction. Phenol, tetralin and pyridine were found to be good reaction solvents for the treatment of coal using solid NaOH in these solvents.     

Extraction of Glycyrrhizic Acid and Glabridin from Licorice

The extraction and separation conditions of glycyrrhizic acid and glabridin from licorice were investigated. By changing the different extraction solvents, procedures, times and temperature, the optimum extraction condition was established: the used of ethanol/water (30:70, v/v) as an extraction solvent, and 60 min dipping time under 50°C. The extracts of licorice were separated and determined by reversed-phase high performance liquid chromatography with a methanol/water (70:30, v/v, containing 1% acetic acid) as the mobile phase. Under the optimum extraction condition, 2.39 mg/g of glycyrrhizic acid and 0.92 mg/g of glabridin were extracted from Chinese licorice and the recoveries were 89.7% and 72.5% respectively.     

提取方法对4种中药雌激素活性的影响

针对4种具有雌激素活性的中药———虎杖、葛根、蛇麻花和女贞子,分别采用水煎和w(C2H5OH)=70%的乙醇水溶液超声法进行提取,用转基因酵母法对其提取产物进行了雌激素活性的测试,对比研究了两种提取方法对4种中药雌激素活性的影响。实验结果显示,虎杖水煎和超声提取样品的EC50分别为3.5×10-3和1×10-3g/L;葛根水煎和超声提取样品的EC50分别为3.5×10-2和1×10-2g/L;女贞子水煎提取样品不显示活性,而超声法提取样品的EC50为2.5×10-3g/L;蛇麻花用这两种方法提取的样品均检测不出雌激素活性。