Lab and pilot-scale ultrasound-assisted water extraction of polyphenols from apple pomace

Apple pomace, a residue from juice or cider production, shows high content of exploitable polyphenols. In this work, apple pomace was submitted to an Ultrasound-Assisted Extraction (UAE) in order to produce extracts rich in antioxidants. After a preliminary study, a solid/liquid ratio of 150 mg of dry material per mL was used, and optimized conditions obtained by response surface methodology for polyphenols water-extraction were 40 °C, 40 min and 0.764 W/cm². A comparison showed Total Phenolics Content (TPC) obtained by UAE was 30% higher than the content obtained by Conventional Extraction (CE)(555 and 420 mg of catechin equivalent per 100 g of dry weight, respectively) and both methods presented the same extraction kinetics. Furthermore, extracts obtained by ultrasound showed higher antioxidant activity, which was confirmed by HPLC analysis, that revealed main polyphenols were not degraded under the applied conditions. The large scale experiments of this ultrasound procedure showed a potential industrial application.     

Supercritical CO2 extraction of oleanolic acid from grape pomace

In this work, we investigated the possibility to extract oleanolic acid through supercritical fluid extraction from waste materials such as grape pomace, which can represent a yet unexploited source of highly added‐value products. Preliminary supercritical fluid extractions were performed on dried grape skin samples and compared with solid–liquid extraction. After optimising extraction parameters such as temperature, pressure and extraction time, the ratio between supercritical and solid–liquid extraction yields was approximately 1/5. Supercritical CO₂ extractions were also carried out on dried grape pomace samples. In this case, the ratio between supercritical and solid–liquid extraction yields was increased up to 1/3, thanks to a combination of static and dynamic extraction and the use of ethanol as modifier. This extraction technique proved successful in extracting oleanolic acid from grape pomace samples with extraction yields that were comparable with those obtained with well‐established extraction techniques such as solid–liquid extraction.     

苹果废渣中天然抗氧化物的提取、分离及活性研究

以苹果渣为原料,用不同浓度乙醇提取得到苹果多酚粗提物,再分别用乙酸乙酯萃取和薄层层析纯化,用猪油POV值测试为跟踪方法对各组分进行筛选,然后以BHT为对照,对最高活性组分与V_c、PG、柠檬酸的协同作用进行了系统探讨。结果表明,95％乙醇的提取效果最好,其干物质以无水乙醇重溶后活性显著提高；PG与苹果多酚的协同效果最好,是对照BHT的2．33倍。     

苹果渣果胶超声波辅助提取工艺优化与抗氧化性研究

目的 优化苹果渣中果胶超声波辅助提取工艺,并考查所提取果胶的抗氧化性.方法 在单因素实验的基础上,选取了料液比、pH、提取温度、超声波功率为因变量,以苹果渣中果胶得率为响应值,应用响应面设计方法建立数学模型并进行分析.结果 料液比、pH、提取温度、超声波功率对苹果渣中果胶得率的影响依次为:料液比＞pH＞提取温度＞超声波...     

杨梅渣中多酚类物质的超声波辅助提取研究

杨梅中的多酚类物质具有独特的生物活性。利用超声波辅助提取杨梅渣中的多酚类物质、总花色苷,得出的最佳提取条件为20kHz的超声频率、30W的超声功率,在60℃下提取70min。      

超临界CO2萃取牡丹籽粕多酚工艺 及其抗氧化性评价

为充分利用牡丹籽粕中的多酚资源,采用响应面法优化超临界CO_2萃取牡丹籽粕多酚工艺,以多酚提取量为响应值,得到了乙醇(夹带剂)体积分数、萃取温度和萃取压力的最优条件;通过测定牡丹籽粕多酚对DPPH和ABTS自由基的清除能力,对其抗氧化活性进行评价。结果表明,超临界CO_2萃取最佳工艺条件为乙醇体积分数83%、萃取温度52℃、萃取压力32 MPa,此条件下牡丹籽粕多酚提取量可达18.58 mg/g;牡丹籽粕多酚和VC对DPPH·清除率的IC_(50)分别为128.22μg/mL和147.72μg/mL,对ABTS~+·清除率的IC_(50)分别为109.18μg/mL和142.66μg/mL,牡丹籽粕多酚对DPPH·和ABTS~+·的清除能力均显著强于VC。     

苹果幼果中酚类物质抗氧化活性研究

为研究苹果幼果多酚抗氧化活性强弱,实验采用四种体外抗氧化评价体系:亚铁还原能力（ferric reducing ability of plasma,FRAP）,DPPH法,邻苯三酚自氧化体系及邻二氮菲-Fe3+-H2O2法初步研究其抗氧化活性。结果表明,苹果幼果多酚具有较强的总还原能力,幼果多酚浓度为90μg/m L时,其对DPPH·、O-2·及·OH的最大清除率分别可达96.96%、70.61%和82.20%,且不同浓度幼果多酚与相应浓度阳性对照间差异显著（p<0.05）。相关性分析表明,幼果多酚与Fe SO4当量浓度、DPPH·清除率、O-2·清除率及·OH清除率之间均存在明显的量效关系。苹果幼果多酚是一种优良的天然抗氧化剂和自由基清除剂。      

山楂中熊果酸的超声提取及抗氧化性研究

采用索氏提取法与超声波法提取山楂中的熊果酸,探讨了山楂中熊果酸超声提取工艺的影响因素,并对熊果酸抗氧化性进行了研究。结果表明:超声波法与索氏提取法相比,熊果酸得率大大提高。通过单因素法和正交实验法得出超声波提取的优化条件为:以50%乙醇为溶剂,功率90W、时间50min、温度50℃、料液比1∶40;熊果酸有较强的清除自由基能力,表现出明显的抗氧化性。     

Effect of pectinase treatment on extraction of antioxidant phenols from pomace,for the production of puree-enriched cloudy apple juices

Effects of pomace maceration on yield, turbidity, cloud stability, composition of phenolics, antioxidant activity and colour properties were studied, to evaluate the potential applicability of enzyme preparations in puree-enriched cloudy apple juice production. The yield of mixed juice and puree from pomace obtained in the enzymatic processing of apple ranged from 92.3% to 95.3%, significantly higher than the yield from the control without enzymatic pomace treatment (81.8%). Higher turbidity was obtained upon pomace treatment with Pectinex XXL and Pectinex Ultra SPL enzymes. The total content of phenolic compounds in apple pomace was higher than in raw juices (1520 mg/kg and 441 mg/L, respectively). The total polyphenol yields were higher in juices treated with Pectinex AFP L-4, Pectinex Yield Mash and Pectinex XXL, as compared to the control treatment. During 6 months of storage, a significant change was observed in the content of polyphenols, especially in procyanidin fractions.     

Supercritical carbon dioxide extraction of antioxidant fractions from selected Lamiaceae herbs and their antioxidant capacity

Antioxidant fractions from four herb spices belonging to the Lamiaceae family: rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis) were isolated using supercritical CO₂ at 35 MPa and 100 °C. The antioxidant fractions were characterized chemically by HPLC-DAD/ESI-ToF-MS. Antioxidant activity of obtained extracts was determined by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5-dimethyl-1-pyroline-N-oxide (DMPO), using electron spin resonance (ESR) spectroscopy. The antioxidant activity of the extracts was compared to the activity of butylated hydroxyanisole (BHA) and Flavor' Plus? water-soluble rosemary extract. In DPPH radical assay the order from the strongest to the weakest antioxidant activity was: BHA, thyme extract, Flavor' Plus?, rosemary and sage extracts, and hyssop extract, while in hydroxyl radical assay order was: Flavor' Plus?, sage extract, rosemary extract, hyssop extract, BHA and thyme extract.Industrial relevanceSpices and herbs have been used not only for flavoring food but also for improving the overall quality of the product and to extend the shelf-life of foods. The present investigation relates to the field of food additives, and particularly to an antioxidant fractions from four herb spices which belong to the Lamiaceae family: rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis). Butylated hydroxyanisole (BHA) and Flavor' Plus? are used in food industry as antioxidants due to their ability to prolong the shelf-life of foodstuffs by protecting them against deterioration caused by oxidation, such as fat rancidity, colour changes, degradation of the flavor and loss of nutrient value. Synthetic antioxidants such as BHA now being replaced by natural antioxidants because of their possible toxicity and due to a suspected action as promoters of carcinogens. The present study confirms that investigated herb spices belonging to the Lamiaceae family present important sources for the production of food additives.     

脱油苹果籽中多酚物质提取的研究

利用脱油苹果籽残渣进行多酚物质提取,通过单因素试验和正交设计得到提取苹果籽多酚的最优提取工艺条件:提取温度45℃、乙醇浓度80％、提取时间35 min、液料比30∶1(V∶m).在该条件下所得脱油苹果籽多酚提取率为3.094 mg/g.     

微波辅助萃取苹果渣中原花青素的工艺研究

为使苹果渣得到更充分的利用,进一步提高苹果渣中原花青素的提取效率,采用正交试验研究微波辅助提取和传统回流提取工艺相结合的苹果渣中原花青素的提取工艺,并与传统的回流提取工艺进行比较.结果表明:丙酮浓度对原花青素得率有极显著影响,微波功率、微波萃取时间、后浸泡时间对原花青素得率有显著影响.最优工艺条件是:微波功率500 W,微波萃取时间90 s,丙酮浓度70%,后浸泡时间15 min,此条件下提取的原花青素含量为0.92 mg/g,明显高于传统回流提取.因此微波辅助提取具有高效、快速、节能的特点.     

微波辅助提取苹果皮中的多酚类物质

以苹果皮为原料提取苹果多酚,对不同提取剂的提取效果进行了比较;通过单因子试验和正交试验对微波辅助提取多酚的工艺条件进行了探讨,研究了溶剂浓度、微波功率、微波处理时间以及料液比对多酚提取的影响;并对微波辅助提取和常规法提取的效果进行了比较。结果表明：综合考虑提取效果及食品安全性,选择乙醇作为提取剂为宜;微波辅助提取的最佳工艺条件为乙醇浓度70%、微波功率210W、微波时间25s、料液比（w/v）1∶5;微波辅助提取法提取物中原花色素含量0.3668mg/ml,常规法提取物中原花色素含量0.2552mg/ml,微波辅助提取效果优于常规法提取。     

甘薯渣多酚粗提液的抗氧化活性研究

多酚具有抗氧化特性。以从甘薯渣中提取的多酚类物质为材料,对其抗氧化性能进行了体外实验,分别测定了甘薯渣多酚粗提液对超氧阴离子自由基(O2-·)、H2O2、羟自由基(·OH)的清除能力及还原能力。结果表明,甘薯渣多酚提取物粗提液具有较强的综合抗氧化能力,是一种有开发价值的天然抗氧化剂。     

响应曲面优化余甘子多酚的亚临界水萃取工艺及其抗氧化性研究

以余甘子干果粉为原料,研究亚临界水萃取余甘子多酚的工艺条件及其抗氧化活性。通过单因素试验探讨了亚临界水萃取余甘子多酚工艺中萃取温度、萃取时间、萃取压力和液料比等因素对多酚提取率的影响,利用响应曲面分析法优化提取工艺。最佳优化工艺参数:余甘子干果粉碎过40目筛,纯水80m L,液料比47∶1,亚临界萃取温度212℃,提取11min,余甘子多酚平均提取率17.08%,实测值与预测值符合良好。高效液相分析表明,亚临界水萃取样品中没食子酸提取率达3.284%,远高于溶剂回流提取。体外抗氧化活性研究表明,亚临界水萃取余甘子多酚具有一定清除DPPH自由基和羟基自由基的能力,其IC50值分别为7.05μg/m L和54.35μg/m L,小于TBHQ和溶剂回流提取样品。体现了亚临界水萃取具有较好的选择性、快速、高效、环境友好等优点。     

苹果多糖提取的优化工艺研究

分别采用碱提、酸提和酶提的单级提取法和各法结合的多级提取法,从苹果渣中提取苹果多糖,通过正交实验等优化各提取方法的工艺参数,结果表明,碱提法优化工艺为:4mol/L NaOH溶液,70℃浸提1h;酸提法优化工艺为:pH2.3,100℃提取3h;酶提法时,采用复合酶组合比单一酶作用提取率高,最佳复合酶组合为:先加3%复合果胶酶,再加3%纤维素酶,最后加入5%α-淀粉酶,每次加新酶后于50℃保温2h.采用优化工艺对苹果多糖进行分级提取,结果比各一步提取法的多糖产率都高,可以有效地提高苹果渣的利用率.     

Phenolic and antioxidant composition of by-products from the cider industry: Apple pomace

Eleven different cider apple pomaces (six single-cultivar and five from the cider-making industry) have been analysed for low molecular phenolic profiles and antioxidant capacity. The Folin index ranged between 2.3 and 15.1 g gallic acid per kg of dry matter. Major phenols were flavanols, dihydrochalcones (phloridzin and phloretin-2′-xyloglucoside), flavonols and cinnamic acids (chlorogenic and caffeic acids). The group of single-cultivar pomaces had higher contents of chlorogenic acid, (-)-epicatechin, procyanidin B2 and dihydrochalcones, whereas the industrial samples presented higher amounts of up to four unknown compounds, with absorption maxima between 256 and 284 nm. The antioxidant capacity of apple pomace, as determined by the DPPH and FRAP assays, was between 4.4 and 16.0 g ascorbic acid per kg of dry matter, thus confirming that apple pomace is a valuable source of antioxidants. PLSR analysis gave reliable mathematical models which allowed to predict the antioxidant activity of apple pomace as a function of the phenolic profile. The variables with the higher modelling power were phloridzin > procyanidin B2 > rutin + isoquercitrin > protocatechuic acid > hyperin.     

水浴提取、超声波和微波辅助提取枇杷叶中熊果酸的比较研究

目的 以熊果酸提取得率为指标, 研究对比水浴提取法、超声波提取法以及微波提取法提取枇杷叶中熊果酸的提取效果。方法 比较提取时间、温度、乙醇体积分数及料液比四个因素下三种方法的提起效果, 并在电子显微镜下进行比较研究。结果 在相同条件下, 微波法和超声波法提取率较接近, 均比水浴法高。在提取时间上, 当采用控温措施时, 超声波法比微波法和水浴法缩短提取时间至少20%, 当不采用控温措施时, 微波法比水浴法缩短时间至少92%, 比超声波法缩短90%;在提取温度上, 微波提取法比超声波法降低提取温度14.3%, 比水浴法降低至少25%;在乙醇体积分数上, 微波法和超声波法提取率均在乙醇体积分数85%时达到最高点, 比水浴法的高6.25%;在料液比上, 超声波法和微波法提取率达到最高点所需的料液比均比水浴法低, 微波法比超声波多消耗溶剂16.7%, 超声波法比水浴法减少消耗至少25%。结论 相比于水浴提取法, 超声波辅助提取法和微波辅助提取法在提取得率和效率上具有明显的优势, 超声波辅助提取法操作简便, 而微波辅助提取法效率更高, 但溶剂消耗更多。     

杏仁及杏仁皮多酚超声提取优化及抗氧化能力差异性研究

为获得杏仁及杏仁皮内多酚提取的最优方案,采用超声波处理样品,以料液比、超声温度、功率和时间为影响因素多酚得率为指标进行研究。结果表明:杏仁多酚超声提取最佳条件为料液比1∶10、超声温度50℃、超声功率400 W,超声时间60 min。而杏仁皮多酚超声提取最佳条件为料液比1∶10、超声温度60℃、超声功率400 W,超声时间60 min。采用还原力、OH、DPPH和ABTS自由基清除率四个抗氧化能力指标对杏仁及杏仁皮多酚的抗氧化能力进行差异性分析,以期为杏仁多酚这一功能性成分的开发提供参考依据。研究结果表明,杏仁多酚抗氧化能力大小与其含量成正比。甜杏仁多酚的还原力、OH和ABTS自由基清除率均高于苦杏仁多酚,而甜苦杏仁多酚的DPPH自由基清除率接近一致,且在0.024 mg/m L浓度时依次为25.4%和23.7%。甜苦杏仁皮多酚抗氧化能力差异不明显,其还原力、DPPH和ABTS自由基清除率三者基本一致,而在0.24 mg/m L浓度时,甜杏仁皮多酚的OH自由基清除率约为苦杏仁皮的2倍。总体来说,甜杏仁多酚的抗氧化能力优于苦杏仁多酚,潜在利用价值更高。