超声辅助双水相提取石榴皮多酚

采用超声辅助双水相法提取石榴皮多酚,在单因素试验的基础上,选取超声时间、超声温度、(NH4)2SO4用量和液料比为自变量,石榴皮多酚得率为响应值,通过Box-Behnken试验设计及响应面分析法,研究各单因素及其交互作用对多酚得率的影响,优化石榴皮多酚的提取工艺条件。研究结果表明:最佳的提取工艺参数为,超声时间32 min、超声温度40℃、(NH4)2SO4用量0.36 g/m L、液料比为37∶1(m L∶g),在此条件下提取,多酚的得率为(10.63±0.28)%(n=3),与模型的预测值10.708 6%有较好的拟合性,表明超声辅助双水相提取石榴皮多酚的方法可行。     

天麻多酚的超声辅助提取工艺优化及抗氧化活性研究

以鲜天麻为试材,研究了天麻总酚的超声辅助提取工艺条件,以最佳工艺对不同干燥条件下的天麻粉进行总酚提取,测定其总酚含量与抗氧化能力,并分析两者的相关性。结果表明,影响天麻总酚提取效果的最主要因素是提取温度,最优工艺条件为:提取温度50℃、提取时间35min、提取功率80 W,料液比1∶10(g/mL),在该条件下,天麻总酚含量最高为5.62 mg/g;不同干燥条件下,55℃热风干燥制得的天麻粉总酚含量最高,达5.754mg/g,其总抗氧化能力、抗超氧阴离子自由基能力、抑制羟自由基能力和DPPH自由基清除能力也最高,同时,天麻总酚含量与其抗氧化能力呈显著相关,说明天麻总酚具有一定的抗氧化能力。     

青叶苎麻叶多酚超声辅助提取工艺优化及抗氧化活性研究

优化了青叶苎麻叶多酚的提取工艺参数,并以没食子酸为对照评价了青叶苎麻叶多酚的抗氧化活性。结果表明:优化出的多酚提取工艺参数分别为料液比(m_苎麻∶V_乙醇)1∶33 (g/mL)、乙醇体积分数40%、提取温度42℃,在此条件下青叶苎麻多酚提取量为47.97 mg/g。青叶苎麻叶多酚清除DPPH自由基和ABTS+自由基的IC₅₀值分别为(0.15±0.00),(2.28±0.03)μg/mL,氧自由基吸收能力为(42.41±0.01)g Trolox/g多酚,均明显优于没食子酸,具有良好的抗氧化效果。     

响应面优化超声辅助双水相提取槟榔多糖及抗氧化活性研究

采用超声辅助双水相提取槟榔多糖,研究料液比、超声温度、超声时间对槟榔多糖提取率的影响,并采用响应面法优化提取工艺条件。结果表明,选用质量比2∶1的（NH4）2SO4-乙醇作为最佳的双水相体系,超声辅助双水相法提取槟榔多糖最佳工艺为料液比1∶20(g/mL)、超声温度70℃、超声时间40 min,槟榔多糖的提取率达到(4.52±0.25)%。DPPH·、ABTS+·、·OH清除试验表明,在一定的浓度范围内,槟榔多糖具有较好的抗氧化性,且呈现良好的量效关系。     

超声辅助提取花生红衣中多酚物质及其抗氧化活性的研究

目的：研究花生红衣中多酚类物质的提取工艺及抗氧化活性。方法：采用超声辅助提取方法,通过单因素和正交试验对花生红衣中多酚类物质(PTP)的提取工艺进行优化;采用还原力和Rancimat 法对其抗氧化活性进行研究。结果：PTP 最佳提取工艺为料液比1:16(g/mL)、乙醇溶液体积分数80%、提取时间10min、提取功率240W;提取因素影响大小顺序为料液比＞乙醇溶液体积分数＞提取时间＞提取功率;在相同质量浓度条件下,纯化后的花生红衣多酚溶液PTP 的还原力强于VC 溶液的还原力;其对猪油抗氧化活性最优的质量浓度为150mg/L;相同质量浓度(150mg/L)条件下,其诱导时间长于VC、没食子酸溶液,而弱于BHT 溶液。     

响应面试验优化辣木叶多酚超声辅助提取工艺及其抗氧化活性

为研究辣木叶多酚超声辅助提取工艺,明确辣木叶多酚体外抗氧化活性,选取超声功率、超声时间、超声温度和料液比为考察指标,研究不同工艺参数对辣木叶多酚提取量的影响,并采用响应面法优化辣木叶多酚提取工艺。此外,研究辣木叶多酚还原力及其对DPPH自由基、超氧阴离子自由基清除能力。结果表明,超声辅助提取辣木叶多酚最优工艺为：超声时间19.5 min、料液比1∶30（g/mL）、超声温度20.2 ℃、超声功率250 W。在此条件下,辣木叶多酚提取量为（25.14±0.46） mg/g。辣木叶多酚具有较强的体外抗氧化活性,其还原力、DPPH自由基和超氧阴离子自由基清除能力分别达到同等质量浓度VC的81.25%、94.15%和75.05%。该研究为辣木叶多酚等生物活性成分高效制备与抗氧化剂的深度开发提供理论依据。     

茼蒿多酚超声辅助提取工艺及其抗氧化活性

为充分利用茼蒿资源,同时检测茼蒿多酚的抗氧化活性,采用超声辅助法在单因素试验的基础上通过正交试验法优化茼蒿嫩叶多酚的提取条件,并对所提取多酚的总抗氧化能力(FRAP测定法)和羟基自由基清除能力进行分析.结果 表明,茼蒿多酚提取的最优条件为液料比20:1mL/g、超声波提取时间100 min、乙醇体积分数70％.此条件下...     

缬草总黄酮超声辅助双水相提取工艺优化及抗氧化活性研究

以缬草为原料,缬草总黄酮得率为指标,采用超声辅助乙醇-硫酸铵双水相体系对缬草总黄酮提取工艺进行单因素及Box-Behnken响应曲面试验优化,并与回流提取所得的总黄酮的还原力、DPPH自由基清除能力、羟自由基清除能力进行抗氧化能力比较。结果表明:缬草总黄酮超声辅助双水相提取的最佳工艺条件为超声时间35 min、硫酸铵用量0.20g/mL、超声温度51℃、液料比为241(mL/g),在该条件下总黄酮提取率为(6.37±0.08)%。两种提取方法所得的缬草总黄酮对DPPH自由基、羟自由基有较强的清除能力和较高的还原力,且超声辅助双水相提取的缬草总黄酮抗氧化能力显著高于一般回流提取。     

桑叶多酚的超声辅助低共熔溶剂提取工艺优化及其抗氧化活性研究

以秋桑叶粉末为原料,采用超声辅助低共熔溶剂法提取桑叶多酚并研究其抗氧化活性。以20种低共熔溶剂对桑叶多酚进行提取,筛选出最优低共熔溶剂组合,在单因素试验的基础上,采用响应面分析法进一步优化桑叶多酚提取工艺参数;采用DPPH和ABTS自由基清除试验分析桑叶多酚低共熔溶剂提取物的抗氧化能力。结果表明：桑叶多酚最佳提取工艺为氯化胆碱/果糖/乙醇摩尔比1:1:2、含水量45%、液料比40 mL/g、超声功率360 W、超声温度40℃、超声时间40 min,在此条件下桑叶多酚提取量为76.82 mg/g;体外抗氧化结果表明,桑叶多酚的抗氧化作用与浓度呈正相关,对DPPH自由基和ABTS⁺自由基有显著的清除作用。     

超声辅助酶解法优化油橄榄果渣多酚提取工艺及其抗氧化活性研究

通过单因素试验和响应面法优化超声辅助酶解法提取油橄榄果渣多酚的工艺，同时用Fe³⁺还原能力(FRAP)法评价多酚的抗氧化能力。结果表明：最优的提取工艺为双酶(纤维素酶和果胶酶质量比1∶1)添加量1.5%(以油橄榄果渣质量计)、超声时间30 min、溶剂pH 3.5、提取温度50℃,在此条件下油橄榄果渣多酚得率为1.798%±0.078%。当油橄榄果渣多酚质量浓度为10 mg/mL时，FRAP值为5.42μg/mL。     

Mode of inhibition of finger millet malt amylases by the millet phenolics

The effect of millet polyphenols on starch hydrolysis catalyzed by amylases developed during malting were investigated. The enzyme kinetic studies using Michaelis–Menten and Lineweaver–Burk equations showed the K_m remained constant (0.625%) but the maximum velocity (V_max) decreased in the presence of a crude extract of millet polyphenols, indicating mixed non-competitive inhibition. On the other hand, gallic acid, vanillic acid, quercetin and trans-cinnamic acid isolated from the polyphenol extract of the millet showed uncompetitive inhibition. Kinetic studies of amylase inhibition by phenolic compounds indicated the presence of secondary binding sites in malted finger millet amylases similar to other cereal amylases.     

超声波辅助双水相体系提取橡实仁多酚的研究

采用超声波辅助双水相体系提取橡实仁多酚,通过单因素实验和正交实验对提取条件进行优化。结果表明:丙酮体积分数对多酚得率有显著影响,硫酸铵用量、超声时间、料液比在考察的范围内对多酚得率影响不显著;橡实仁多酚的最佳提取条件为:丙酮体积分数80%,硫酸铵用量0.16g/mL,超声时间25min,料液比(W/V)1:45;在此条件下进行了验证实验,得到橡实仁多酚的平均得率为3.3033mg/g,RSD为0.7674%,表明提取结果稳定性极好。     

Evaluation of antioxidant and antimicrobial properties of finger millet polyphenols (Eleusine coracana)

Phenolic acids from finger millet (Eleusine coracana) milled fractions (whole flour, seed coat, 3%, 5% and 7%) were isolated and their antioxidant and antimicrobial properties were evaluated. Acidic methanol extracts from seed coat to whole flour were rich in polyphenol content and were found to be stable up to 48 h at pH 4, 7, and 9 as studied by ultraviolet spectroscopy. Diadzene, gallic, coumaric, syringic and vanillic acids were identified as major phenolic acids from the extracted phenolics. Diadzene content was highest in concentration in the 5% flour. The reducing power of seed coat extract was significantly (p < 0.05) higher than that of whole flour extract. Antioxidant activity (AA) as determined by the β-carotene–linoleic acid assay indicated that the AA was highest in seed coat extract (86%), whilst at the same concentration it was only 27% in the whole flour extract. The seed coat extract showed higher antimicrobial activity against Bacillus cereus and Aspergillus flavus compared to whole flour extract. From these observations, it can be inferred that the polyphenols are responsible for the microbial activity of the millet and the results indicate that potential exists to utilise finger millet seed coat as an alternative natural antioxidant and food preservative.     

神秘果种子多酚超声双水相复合提取工艺及其抗氧化活性

利用超声波与双水相体系复合提取神秘果种子多酚,研究不同条件下提取的多酚的抗氧化能力。分别考察丙酮浓度、硫酸铵用量、超声波温度、超声波时间、料液比对神秘果种子多酚提取率的影响;采用单因素试验及响应面设计,优化神秘果种子多酚提取工艺。结果表明,最佳提取工艺条件为:丙酮浓度50%、硫酸铵用量0.22g、超声波温度60℃、超声波时间100min、液料比1∶20(m∶V),多酚理论提取率为11.54%。该条件下神秘果种子多酚的平均提取率为11.56%。该体系提取的多酚纯度为87.85%,优于单独采用超声波提取,可实现初步纯化。抗氧化性试验结果表明,神秘果种子多酚提取物对DPPH·的清除能力和还原能力较强,且还原力和DPPH·清除率与总多酚含量呈正比关系;其抗氧化活性强于抗坏血酸。     

Influence of major polyphenols on antioxidant activity in Mencía and Brancellao red wines

The purpose of this work was to examine the relationship of the total polyphenol index (TPI) as measured spectrophotometrically and individual phenols as determined by HPLC to antioxidant activity in red wines made from two Vitis vinifera grape varieties grown in NW Spain (viz. Mencía and Brancellao) during bottled storage in the dark for 12 months. Antioxidant activity was determined by using various methods based on inhibition of the coupled oxidation of the β-carotene/linoleic acid mixture. Also, free radical scavenging activity was determined with 2,2-diphenyl-1-picrylhydrazyl (DPPH). Antioxidant activity as measured by DPPH after storage for 3 months was higher in Mencía wines than in Brancellao wines (4.5 ± 0.60 vs. 3.7 ± 0.30 mmol/L trolox equivalents). Beyond 3 months of storage, radical scavenging activity increased in both types of wine (from 4.5 ± 0.60 to 6.0 ± 0.80 mmol/L in Mencía wines and from 3.7 ± 0.30 to 4.7 ± 0.71 mmol/L trolox equivalents in Brancellao wines). The significant correlation found between antioxidant activity and TPI in all wines (r > 0.88) is indicative of the significance of condensation and polymerisation products to the total antioxidant activity of the wines. The relatively high correlation of total flavonols (r = 0.89) and acylated anthocyanins (r = 0.70) as measured by HPLC with to the overall antioxidant capacity suggests that these two polyphenol classes can substantially influence the antioxidant properties of these wines. The linoleic acid/β-carotene assay exposed a higher antioxidant capacity in Brancellao wines than in Mencía wines after 3 months of storage (6.0 ± 0.80 vs. 4.7 ± 0.70). Most of the studied wines lost an average 45% antioxidant activity during bottled storage. Antioxidant activity as measured with the linoleic acid/β-carotene assay was closely correlated with both hydroxycinnamic acids (r = 0.90) and flavanols (r = 0.71 and 0.61 for monomeric and polymeric forms, respectively).     

Aqueous two-phase extraction,identification and antioxidant activity of anthocyanins from mulberry (Morus atropurpurea Roxb.)

Aqueous two-phase extraction (ATPE), identification and antioxidant activity of anthocyanins from mulberry (Morus atropurpurea Roxb.) were investigated in this study. The optimal differential partitioning of mulberry anthocyanins (MAY) and sugars was achieved in a system (pH 4.5, temperature = 35 ± 1 °C) composed of 30% (w/w) ethanol, 20% (w/w) concentration of ammonium sulphate, 10% (w/w) mulberry juice and 40% (w/w) water. The multiple partitioning indicated a single ATPE step could isolate the majority of anthocyanins, while removing near to 90% of the free sugars. The composition of the MAY extracted by ATPE had no obvious changes, and five anthocyanins were identified by HPLC–ESI-MS/MS. The ATPE extract showed a relatively high antioxidant ability compared to that by the conventional extraction. Our results indicated that ATPE was a valuable method for the removal of the majority of free sugars, which held great promise in the purification of natural anthocyanin pigments.     

响应面法优化超声提取芝麻粕中多酚工艺及其抗氧化活性研究

采用超声辅助提取芝麻粕中多酚。通过单因素试验考察提取溶剂、超声功率、超声温度、液料比、超声时间对多酚产率的影响,在此基础上,基于Box-Behnken进行了四因素三水平响应面优化设计,并测定了芝麻粕多酚提取物体外抗氧化活性。结果表明:超声辅助提取芝麻粕中多酚的最佳提取条件为以60%乙醇溶液为提取溶剂、超声功率320 W、超声温度54℃、液料比57∶1、超声时间30 min,此条件下多酚产率为2. 86%,与预测值(2. 95%)无显著性差异。与食品抗氧化剂TBHQ相比,芝麻粕多酚提取物具有较强的体外抗氧化活性,芝麻粕多酚提取液清除DPPH·的能力(IC_(50)为34. 91μg/m L)大于TBHQ的(IC_(50)为92. 40μg/m L)。     

Multiple molecular forms of finger millet subtilisin and amylase inhibitors

Nine varieties of finger millet (Eleusine coracana Gaertn) including a wild form were screened for proteinase and α-amylase inhibitory activities. Subtilisin inhibitory activity was present in all the varieties examined and was highest in the wild form, while the cultivated varieties had more trypsin inhibitory activity. Isoelectric focusing of a 60% ammonium sulphate fraction of the wild form, before and after complexing with subtilisin, showed multiple forms of subtilisin inhibitors one of which was also active against trypsin. Isoforms of finger millet subtilisin inhibitors were isolated from the ammonium sulphate fraction by ion exchange chromatography on DEAE-Sephadex followed by SP-Sephadex chromatography. Copurification of trypsin and α-amylase inhibitory activities with subtilisin inhibitory activity was observed during cation exchange chromatography. PAGE analysis revealed them to be charge isomers with pI in the range 5·5–6·0. SDS–PAGE gave an estimate of 12 000 mol wt for each of them. Finger millet subtilisin inhibitors were more active on bacterial proteinases than on bovine trypsin and chymotrypsin.     

超声波提取牡丹籽壳多酚工艺响应面法优化及抗氧化性研究

采用超声波提取牡丹籽壳多酚,以多酚含量为指标,通过单因素实验分别考察乙醇体积分数、液料比、提取时间和提取温度的影响,并采用响应面法获得最优的超声波提取牡丹籽壳多酚的工艺条件。以抗氧化剂(VC和BHT)为参照,采用DPPH和FRAP法评估牡丹籽壳多酚的抗氧化性。结果表明,超声波提取牡丹籽壳多酚最优工艺条件为:超声波功率100 W,乙醇体积分数70%,液料比25∶1,提取时间80 min,提取温度60℃;在最优条件下,多酚含量为5.75%。牡丹籽壳多酚清除DPPH自由基的IC50为71.0μg/m L,FRAP值为18.33 mmol/L,具有一定的抗氧化作用。     

Evolution of the colour,antioxidant activity and polyphenols in unusually aged Sherry wines

The present paper reports the results of a study monitoring several key analytical parameters in a set of aged samples of vintages from 1999 back to 1935. The analysed parameters were: colour, antioxidant activity, low molecular weight phenolics, index of total polyphenols and SO₂ content.