Assisted extraction of rosemary antioxidants with green solvents

The use of natural antioxidants in the food industry has increased in the last years and there is a growing interest in improving the extraction processes using GRAS (general recognize as safe) solvents. In this work the extraction of antioxidants from rosemary with ethanol and water as solvents has been studied using different extraction processes (conventional, microwave assisted - MAE - and ultrasound assisted - USAE -) and plant pretreatments (deoiled and milled, deoiled and fresh plant). Total phenolic compounds in the extracts were determined by the Folin-Ciocalteu assay and HPLC with UV detection was employed for the quantitation of the main antioxidant compounds: rosmarinic acid and carnosic acid. The antioxidant activity of the extract was determined by the DPPH scavenging assay. The double pretreatment, deoiling by solvent free microwave extraction (SFME) and milling, has shown to be essential to overcome inner mass transfer limitations. Extraction efficiency can be additionally enhanced by microwave and ultrasound assisted extraction process, being this latter more significant in aqueous extracts.     

超临界二氧化碳萃取猕猴桃籽油的研究

采用超临界萃取方法，以二氧化碳作为溶剂，从猕猴桃籽中提取猕猴桃籽油，着重探讨了萃取压力、萃取温度、萃取时间等参数对萃取结果的影响，并确定了最佳的工艺条件；在此条件下萃取效率可达97％以上，与传统工艺进行比较，超临界萃取是一种优异的提油方法。     

Ultrasound‐assisted extraction kinetics,fatty acid profile,total phenolic content and antioxidant activity of green solvents' extracted passion fruit oil

The main objective of this current work was to evaluate the feasibility of green solvent's application on passion fruit oil extraction. In this study, the effects of green solvent on oil yield, fatty acid profile, oil physicochemical properties, total phenolic content and antioxidant activity associated with extracted oil were compared to those of conventional solvent, hexane application. Therefore, this study may provide supplementary information on previous studies that focused on oil recovery. Oilseeds' proximate composition and the influence of oilseeds‐to‐solvent (w/v) ratio on oil yield were investigated. The oilseeds contained high fibre, fat and protein. Oilseeds‐to‐solvent (w/v) ratio (1:8) provided the highest oil yield. Overall, acetone was suggested as a suitable hexane replacer due to its higher oil recovery, similar fatty acid profile and oil physicochemical properties with higher antioxidant activity. Ethanol‐extracted oil contained higher amounts of omega‐9 MUFA, which may indicate the influence of extraction solvent on final fatty acid composition and thus final oil application.     

食品工业中的超声提取技术

应用超声强化提取过程可有效地提高提取效率，缩短提取时间，节约成本，甚至还可以提高产品的质量和产量。本文论述了超声波与媒质的基本作用及其产生的效应，超声提取技术在食品工业中的应用，并阐述了超声强化提取的机理，指出了该技术所存在的问题和研究方向。     

乙醇沉淀法提取葡萄多糖的研究

利用乙醇沉淀法提取葡萄多糖。研究表明此法提取葡萄多糖的最佳条件为：温度90℃，时间2h，料液体积比1：2，次数为3。在提取液浓缩至原体积1／10的基础上用6倍体积的体积浓度95％乙醇进行沉淀。根据最佳提取工艺可使葡萄多糖的提取率达到99．9％。     

乙醇沉淀法提取葡萄多糖的研究

利用乙醇沉淀法提取葡萄多糖。研究表明此法提取葡萄多糖的最佳条件为:温度90℃,时间2h,料液体积比1∶2,次数为3。在提取液浓缩至原体积1/10的基础上用6倍体积的体积浓度95%乙醇进行沉淀。根据最佳提取工艺可使葡萄多糖的提取率达到99.9%。     

Supercritical fluid extraction of tea seed oil and its comparison with solvent extraction

Supercritical fluid extraction (SFE) of tea seed oil was performed to study the effects of various parameters such as pressure, temperature, extraction time (dynamic) and modifier (ethanol) on the yield and composition of the oil. The results were also compared with those obtained by Soxhlet extraction, ultrasonic extraction, and DGF (Deutsche Gesellschaft für Fettwissenschaft) standard method B-I5 (87) in lab conditions. The yield of tea seed oil obtained using SFE was similar to or higher than the other methods. The results from SFE showed that the modifier and pressure have significant effects on the extraction efficiency. The oil extracted by SFE in the absence of modifier was clearer than the oils obtained in other conditions. The fatty acid composition of each extract was determined by gas chromatography. Palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2) and gadoleic (C20:1) fatty acids were observed in the oil samples. Since it contains high-unsaturated fatty acids (UFA) and low saturated fatty acids (SFA), edible tea seed oil is also relatively healthy.     

白花菜籽油的制备及脂肪酸组成分析

采用溶剂浸提法提取白花菜籽油,对其提取工艺条件进行了研究,并用气相色谱法对其脂肪酸的种类和相对含量进行了测定。结果显示,以异丙醇为浸提溶剂,料液比(质量体积比)为1∶7,浸提时间为60 min,浸提温度为60℃时,白花菜籽油的提取率最高为28.4%。利用气相色谱鉴定出14种脂肪酸,主要有亚油酸(62.65%)、油酸(20.66%)、棕榈酸(10.98%)、硬脂酸(4.18%),饱和脂肪酸质量分数为15.68%,不饱和脂肪酸质量分数为84.32%,其中单不饱和脂肪酸质量分数为21.01%,二不饱和脂肪酸质量分数为62.65%,三不饱和脂肪酸质量分数为0.67%。     

响应面优化百香果果皮黄酮提取工艺

本实验以百香果果皮为原料,采用超声提取工艺,探索乙醇浓度、料液比、提取时间、提取温度、超声功率这五个实验因素对黄酮提取率的影响。在单因素实验结果的基础上,采用响应面建立了提取百香果果皮中黄酮的二次多项数学模型,并进一步验证了该模型的有效性,同时利用响应面分析法对提取工艺进行优化。结果表明:在乙醇浓度60%、提取时间40 min、提取温度50℃,料液比(g/mL)1∶50,超声功率250 W条件下,测得黄酮得率为19.2124 mg/g,该工艺提取量稳定,方法简单、可靠。     

水酶法提取光皮树油的研究

从市售的木聚糖酶、淀粉酶、纤维素酶、中性蛋白酶、复合植物水解酶、果胶酶中筛选提取光皮树油的水解酶,实验结果得到纤维素酶对光皮树果实的提油作用最强,其提油率达65.29%,复合植物水解酶次之,为64.05%,木聚糖酶效果最差,仅为54.47%。通过单因素实验得到纤维素酶提取光皮树油的最适工艺条件为:酶解pH 5.8,料液比1∶3,酶加量2.5%,酶解温度40℃,酶解时间4h。该条件下,油的乳化率低,提出来的基本上是清油,且提油率达76.64%。     

Temperature-dependent diffusion coefficient of oil from different sunflower seeds during extraction with hexane

Oil extraction from confectionery, oilseed and wild sunflower seeds with n-hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent-ground seed ratios are reported. A mathematical model of oil extraction from seeds of sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10⁻¹² to 1.87 × 10⁻¹² m²/s for confectionery, 2.06 × 10⁻¹² to 5.03 × 10⁻¹² m²/s for oilseed, and 9.06 × 10⁻¹³ to 1.18 × 10⁻¹² m²/s for wild sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild sunflower, respectively.     

An overview of papaya seed oil extraction methods

Papaya seeds account for about 20% of the total fresh fruit weight. The seeds are generally discarded as agricultural waste products during fruit processing despite being edible. The seeds contain high levels of lipid and thus can be a new source of edible oil. Numerous technologies have been used for extraction of crude oil from papaya seeds. Papaya seed oil is composed mostly of unsaturated fatty acids with oleic acid being the major one. The oil also contains lipophilic phytochemicals such as tocopherols, phytosterols and carotenoids. Further investigations are necessary to validate the functional properties of papaya seed oil produced from different extraction techniques.     

百香果醋生产工艺的研究

对百香果醋研制中的酒精发酵、醋酸发酵过程进行了研究,确定酒精发酵的适宜条件为发酵时间48h,发酵温度32℃,接种量10％;醋酸发酵的最适条件为发酵温度32℃,接种量10％,发酵醪酒精含量6％vol。     

黄色和紫色百香果籽油抗氧化作用的对比研究

本论文对比分析了两种百香果籽油中的抗氧化物质含量。两种百香果籽油中均含有黄酮、β-胡萝卜素和维生素E,其中黄酮含量最高,达到45μg/m L左右,黄色百香果籽油和紫色百香果籽油的总酚含量分别达到16.69、15.82 mg GAE/kg。比较分析了两种百香果籽油对铁离子的还原能力和对DPPH自由基、超氧阴离子自由基（O-2·）和羟自由基（·OH）的清除效果等的抗氧化作用,结果紫色百香果籽油的铁离子还原能力和清除DPPH自由基的能力强于黄色百香果籽油,而清除羟自由基和超氧阴离子能力则相反,两种百香果籽油对DPPH自由基的最高清除率都高于84%,对超氧阴离子自由基的最高清除率都超过80%。实验结果表明两种百香果籽油均具有较强的抗氧化活性。      

茶叶浸提液微波辅助萃取过程中溶剂选择的差异

研究了绿茶中活性成分儿茶素单体在不同性质的溶剂(甲醇、乙醇、水、乙酸乙酯)下,微波辅助萃取的效率和选择性差异。实验结果发现,酯型儿茶素单体(L-EGCG和L-ECG)用甲醇或乙醇萃取较用水萃取效率高,其他三种简单儿茶素单体(L-EGC,D,L-C,L-EC)则是以纯水作为萃取溶剂萃取效率为佳。乙酸乙酯对儿茶素各单体的浸出量相对水、甲醇和乙醇都大幅减少。适当增加萃取溶剂的离子浓度,会有利于微波辅助萃取效率的提高,但溶剂的离子浓度过大时,会降低儿茶素各单体的浸出量。     

正己烷、正庚烷、正戊烷浸出大豆油动力学特性研究

采用平板模型建立浸出动力学模型,确定正己烷、正庚烷、正戊烷等不同溶剂浸出大豆油浸出参数和对浸出过程影响。结果表明:采用平板模型建立数学指数模型能较好描述浸出过程,回归分析得出浸出速率和平衡系数,表明溶剂不同对油料浸出效果有较大影响,油脂萃取过程中正庚烷浸出速率较大和扩散系数较高,使用正戊烷萃取后大豆粕残油率较低。     

百香果籽油超临界CO2萃取工艺优化及其体外抗氧化活性

以百香果为原料,在单因素试验基础上,采用Box-Behnken响应面分析,优化超临界CO_2萃取百香果籽油的工艺,并对百香果籽油的体外抗氧化活性进行研究。结果表明,超临界CO_2萃取百香果籽油的最佳工艺为萃取温度53.1℃,萃取压力33.9 MPa,萃取时间3.6h,百香果籽出油率值为26.95%,所得百香果籽油具有较好的还原力,且呈量效关系,对DPPH·的清除能力达80%。超临界CO_2萃取百香果籽油工艺稳定可行,提取的百香果籽油具有抗氧化活性,是一种潜在可用的天然抗氧化资源。     

Study on extraction technology of flavonoids from natural green cotton fiber

Abstract

Studies have shown that the number of flavonoids between colored cotton and dyed cotton is quite different. Flavonoids content of natural colored cotton is higher than that of white cotton or dyed cotton, so natural colored cotton and dyed cotton can be distinguished by the content of flavone in fibers. Extraction of flavonoids is essential for identification, but there is a lack of simple and trustable extraction method in the market so far for this purpose. This study aim is to explore the most effective method of extracting flavonoids from cotton fibers. Single factor experiment and orthogonal experiment have been designed to get the effect of experimental conditions on the extraction of flavonoids from cotton fibers, and the optimized extraction process has been obtained. Five variables, including the liquid-solid ratio, ethanol concentration, extraction temperature, extraction time, sodium hydroxide concentration, were selected as the main factors, and each factor was studied at four levels. The UV absorbance value at 264?nm was used to evaluate the effect of different extraction conditions on the extraction rate of flavonoids from natural green fibers. The results showed that the extraction efficiency was influenced mostly by ultrasonic temperature, followed by ethanol concentration, the liquid-solid ratio, sodium hydroxide concentration and ultrasonic time. The optimized extraction conditions have been concluded as 1:40 liquid-solid ratio, 50% ethanol concentration, 70?°C extraction temperature, 1?h extraction time, 0.15% sodium hydroxide concentration.     

百香果籽油对衰老小鼠运动耐力及抗疲劳功能研究

通过向衰老小鼠施用百香果籽油,研究百香果籽油对衰老小鼠运动耐力和生化指标的影响。结果表明:灌服百香果籽油的衰老小鼠跑步时间和负重游泳的力竭时间均显著增加(P 0.05),血清尿素氮和血乳酸含量显著减低(P 0.05),肝糖原和肌糖原能够满足机体的对能量的需求。同时,衰老小鼠机体内丙二醛含量显著降低(P 0.05),超氧化物歧化酶和谷胱甘肽过氧化物酶的活力升高。并且,灌服200 mg/(kg·d)剂量时,衰老小鼠的运动耐力和生化指标均最好。综上,百香果籽油能够对抗D-半乳糖对小鼠造成的衰老,显著提升衰老小鼠的运动耐力。