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.     

超临界CO2萃取条件对紫苏籽油脂肪酸组成的影响及工艺优化

利用超临界萃取技术提取紫苏籽油,研究萃取压力、萃取温度、萃取时间、CO_2流量对主要脂肪酸组分含量的影响,并以亚麻酸萃取率为评价指标采用正交试验进行工艺优化。结果表明,棕榈酸、硬脂酸含量与萃取压力和萃取时间负相关,因萃取温度与CO_2流量的变化趋势是先降后升;油酸、亚油酸含量因CO_2流量的变化趋势是先降后升;亚麻酸含量与萃取压力和萃取时间正相关,因萃取温度与CO_2流量的变化趋势是先升后降。超临界CO_2萃取紫苏籽油的最佳工艺条件为:萃取压力25 MPa、萃取温度40℃、萃取时间2.0 h、CO_2流量20 L/h。在该工艺条件下亚麻酸萃取率为88.09%。所得紫苏籽油符合食用植物油质量要求。     

Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties

Mango biowastes, obtained after processing, contain large amounts of compounds with antioxidant activity that can be reused to reduce their environmental impact. The present study evaluates the effect of solvent (methanol, ethanol, acetone, water, methanol:water [1:1], ethanol:water [1:1], and acetone:water [1:1]), and temperature (25, 50, and 75 °C) on the efficiency of the extraction of antioxidants from mango peel and seed. Among the factors optimized, extraction solvent was the most important. The solvents that best obtained extracts with high antioxidant capacity were methanol, methanol:water, ethanol:water, and acetone:water (β-carotene test, antioxidant activity coefficient 173 to 926; thiobarbituric acid reactive substances test, inhibition ratio 15% to 89%; 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid ABTS(·+); and 2,2-diphenyl-1-picrylhydrazyl DPPH· scavenging, 7 to 22 and 8 to 28 g trolox equivalent antioxidant capacity [TE] per 100 g mango biowaste on a dry matter basis [DW]). Similarly, the flavonoid (0.21 to 1.4 g (+)-catechin equivalents per 100 g DW), tannin (3.8 to 14 g tannic acid equivalents per 100 g DW), and proanthocyanidin (0.23 to 7.8 g leucoanthocyanidin equivalents per 100 g DW) content was highest in the peel extracts obtained with methanol, ethanol:water, or acetone:water and in the seed extracts obtained with methanol or acetone:water. From the perspective of food security, it is advisable to choose ethanol (which also has a notable antioxidant content), ethanol:water, or acetone:water, as they are all solvents that can be used in compliance with good manufacturing practice. In general, increasing temperature improves the capacity of the extracts obtained from mango peel and seed to inhibit lipid peroxidation; however, its effect on the extraction of phytochemical compounds or on the capacity of the extracts to scavenge free radicals was negligible in comparison to that of the solvent. PRACTICAL APPLICATION: There are many antioxidant compounds in mango peel and seed, and they could be used as a natural and very inexpensive alternative to synthetic food additives. However, the conditions in which the antioxidants are extracted must be optimized. This work proves that conditions such as extraction solvent or temperature have a crucial impact on obtaining extracts rich in antioxidants from mango biowastes.     

羊肚菌多糖的提取优化及抗氧化活性研究

摘要：目的 对羊肚菌多糖（Morchella esculenta polysaccharides,MEP）的提取工艺进行筛选优化,获得最佳工艺和最佳活性组分。方法 采用热水浸提（Hot water extraction,HWE）、柠檬酸提取（Citric acid extraction,CAE）、碱提（Alkaline solution extraction,ASE）和低共融溶剂提取（Deep eutectic solvent extraction,DESs）4种方法,获得4种多糖（MEP-W、MEP-S、MEP-A和MEP-D）,通过比较选出最佳方法,采用响应面设计获得最佳工艺,采用乙醇分级获得三个组分MEP30、MEP60和MEP80,通过自由基清除试验（DPPH· 和·OH）和还原力测定评估其抗氧化活性。结果 HWE为最佳方法,最佳提取工艺为：时间3 h,液料比44∶1（mL/g）,温度83.6℃,提取得率为（8.13±0.38）%。MEP80在三个组分中清除·OH能力和还原力最强,EC50和RP0.5AU分别为0.44 mg/mL和1.52 mg/mL,高于其前体物MEP-W。结论 热水浸提为最佳方法,MEP80为抗氧化活性的最佳组分,值得进一步研究。     

马齿苋全草油的亚临界流体萃取、脂肪酸分析及抗氧化活性

以马齿苋全草油提取率为考察指标,通过单因素实验和正交实验确定亚临界异丁烷萃取技术提取马齿苋全草油的最佳提取工艺;采用气相色谱-质谱联用仪(GC-MS)分析马齿苋全草油的脂肪酸组成,同时通过羟基自由基(·OH)、DPPH·自由基和总抗氧化能力3个体外抗氧化模型评价马齿苋全草油抗氧化活性。结果表明:亚临界异丁烷萃取技术的最优工艺条件为,萃取压力0.8 MPa,萃取温度40℃,萃取时间150 min,提取率达2.91%;GC-MS分析结果表明,马齿苋全草油主要含有33.19%亚油酸(∞-6多不饱和脂肪酸)和31.04%亚麻酸(∞-3多不饱和脂肪酸);并且马齿苋全草油具有明显的总抗氧化活性并且对DPPH·和·OH具有一定的清除能力。     

Effect of lactobacilli inoculation on cassava (Manihot esculenta) silage: Fermentation pattern and kinetic analysis

The major effect of Lactobacillus inoculation on laboratory cassava (Manihot esculenta Crantz) silage was a change from a heterofermentative pattern observed in natural silage to a homofermentation. Small amounts of starter culture (1% v/w) were required to produce a high level of lactic acid (> 28 g kg^?1 DM) and to reach a pH of at least 4. The Gompertz model was used to evaluate the effect of inoculation level on the lactic formation based on kinetic criteria. Also an empirical pH lactic acid correlation was proposed to monitor the progress of ensiling, based solely on pH measurements. The simulation model may be used to improve guidelines for silo safety and to evaluate the effect of lactobacilli inoculants.     

Supercritical fluid extraction of antioxidant and antimicrobial compounds from Laurus nobilis L. Chemical and functional characterization

Extraction of laurel leaves by using supercritical carbon dioxide was carried out on a supercritical fluid (SF) pilot-scale plant. The extraction pressure and temperature were set to 250 bar and 60°C, respectively, using a 4% of ethanol as modifier. The employed apparatus, owing to a two-stage separation, allowed us to obtain two different fractions (F1 and F2), whose antioxidant and antimicrobial activities were investigated. Two different methods, β-carotene bleaching test and DPPH^• free radical–scavenging assay, were carried out to determine the antioxidant activity. Moreover, antimicrobial activity of laurel fractions was tested against Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 10145, Escherichia coli ATCC 11775, Candida albicans ATCC 60193 and Aspergillus niger ATCC 16404. Minimum inhibitory concentration (MIC) and minimal bactericidal and fungicidal concentration (MBC) were obtained. Both fractions showed a similar antioxidant activity, although it was slightly higher for the fraction recovered in separator 2. However, antimicrobial activity against the microorganisms tested was only found when fraction 2 was used. Staphylococcus aureus was the most sensitive microorganism to this fraction, with maximal inhibition zones (25 mm) and the lowest MBC values (1.25 mg/ml), whereas the least susceptible was the fungi Aspergillus niger. In order to determine the compounds responsible for the antimicrobial activity, fraction 2 was analysed by GC–MS; results obtained showed that most of the compounds identified in the supercritical extract have been previously described to show antimicrobial activity; among them, the major compound found in the supercritical extract corresponded to a sesquiterpene lactone of the germacrolide type (6-epi-desacetyllaurenobiolide) previously described in laurel.     

Inhibitory effect of raspberries on starch digestive enzyme and their antioxidant properties and phenolic composition

Seven primocane fall-bearing raspberry (Rubus idaeus L.) cultivars, Nova (red), Dinkum (red), Heritage (red), Autumn Britten (red), Josephine, Anne (yellow), Fall Gold (yellow) were analysed for potential health promoting properties including their inhibitory effect on starch and fat digestive enzymes, antioxidant activities, and phenolic composition. The tested raspberry extracts showed no detectable inhibition of pancreatic α-amylase and lipase. However, all the extracts exhibited potent inhibition of α-glucosidase with IC₅₀ from 16.8 to 34.2 μg/mL. Four phenolic compounds, ellagic acid, cyanidin-diglucoside, pelargonidin-3-rutinoside, and catechin were identified as the active α-glucosidase inhibitors. The raspberry extracts also possessed significant antioxidant activities with oxygen radical absorbance capacities (ORAC) ranging from 136.7 to 205.2 μmol Trolox equivalents (TE)/g dry weight fruit and DPPH radical scavenging activities from 305 to 351 μmol TE/g. The total phenolic content of raspberry cultivars varied significantly from 40.9 to 98.5 mg of gallic acid equivalents/g dry weight. The anthocyanin content varied widely from 0.1 to 9.5 mg cyanidin 3-glucoside equivalents/g. Nine phenolic acids were quantified in raspberries and their total amounts varied from 157.3 to 713.5 μg/g. The enzyme inhibition and antioxidant properties of raspberry cultivars were not correlated with their total phenolic, anthocyanin, and phenolic acid content. Overall, ‘Dinkum’ and ‘Josephine’ raspberry varieties possess higher total phenolic content, ORAC, DPPH radical scavenging activity, and α-glucosidase inhibitory activity than other five cultivars.     

籽粒苋油的超临界CO2萃取及其色谱分析

应用超临界CO2萃取技术,研究了籽粒苋油的提取工艺.采用三因素三水平正交试验,考察了萃取压力、温度、CO2流量对籽粒苋油萃取率的影响.研究得出最佳萃取条件为:萃取压力35 MPa,萃取温度35℃,CO2流量10 L/h.在最佳萃取条件下,籽粒苋油萃取率达5.96%.利用气相色谱仪分析了籽粒苋油的脂肪酸组成,结果表明,籽粒苋油总不饱和脂肪酸含量高达70%,还含有7.14%的角鲨烯,是一种理想的营养保健食用油.     

Studies on the synthesis and properties of hydroxypropyl derivatives of cassava (Manihot esculenta Crantz) starch

Cassava starch was subjected to hydroxypropylation in three different media, which included water, water in the presence of a phase transfer catalyst, and 2‐propanol, all at 30 ± 2 °C for 24 h. Propylene oxide was used in four different concentrations (50, 100, 150 and 200 g kg^?1 of starch dry weight). The products were characterized by determining their molar substitution (MS), structural and functional properties. The analyses were done in triplicate and the data were analyzed using the statistical package 8.01. The MS of the products ranged from 0.26 to 1.41. The MS of the hydroxypropyl derivatives were found to be higher when the reaction was carried out in the aqueous medium in the presence of tetrabutylammonium bromide, a phase transfer catalyst, when compared to the reaction in 2‐propanol, which was found to be not very effective at 30 ± 2 °C. The etherification altered the granular properties of starch, as could be seen from scanning electron micrographs. Hydroxypropylation resulted in starch pastes which were stable and with higher swelling volume, solubility, light transmittance and water binding capacity as compared to native starch. The hydroxypropyl starches showed significantly lower pasting temperatures and setback viscosities. The enzyme digestibility of the derivatives was seen to decrease with increase in MS and there was a significant reduction in the syneresis of the starch pastes of hydroxypropyl derivatives. Texture profile analysis showed that hydroxypropylated starch gels exhibited higher hardness, springiness (elasticity) and gumminess and lower cohesiveness than the native starch. Copyright © 2007 Society of Chemical Industry     

羊肚菌多糖纯化、结构分析及抗氧化活性

对羊肚菌多糖(Morchella esculentapolysaccharides,MEP)进行分离纯化,对多糖组分进行纯度鉴定及结构分析。利用DEAE-52纤维素层析柱和Sephadex G-100层析柱纯化得到2种组分(MEP-2和MEP-3),均为均一多糖。利用红外图谱(fourier transform infrared spectroscopy,FT-IR)和刚果红实验分析内部结构,MEP-2是一种吡喃环多糖且具有双螺旋结构,MEP-3含有甘露糖无双螺旋结构。利用高效凝胶渗透色谱法(high-performance gel permeation chromatography,HPGPC)与高效液相色谱法(high-performance liquid chromatography,HPLC)测定2种组分分子量及单糖组成,MEP-2由甘露糖、葡萄糖、半乳糖、阿拉伯糖组成,摩尔比为2.97∶13.69∶1∶2.60,分子质量为8.3 kDa。MEP-3由甘露糖、鼠李糖、葡萄糖、半乳糖组成,摩尔比为18.25∶0.84∶1∶1.53,分子质量为11.6 kDa。扫描电镜(scanning electron microscope,SEM)和原子力显微镜(atomic foree microseope,AFM)对MEP-2和MEP-3的组成和结构进行分析,MEP-2呈现不同大小的球形构象,MEP-3主要为球状和片状。MUP-3清除DPPH自由基、·OH、ABTS·的能力、还原力优于MUP-2,清除O2-·的能力弱于MUP-2。     

软枣猕猴桃籽油的超临界萃取及成分分析

用正交实验对超临界CO2流体萃取软枣猕猴桃籽油的工艺条件进行了优化,并用气相色谱法对软枣猕猴桃籽油中脂肪酸种类和含量进行了测定.结果表明,萃取温度为40℃,萃取压力为35 MPa,萃取时间为2.5 h的条件下,软枣猕猴桃籽油的出油率达到20.8%.软枣猕猴桃籽油中主要含棕榈酸、亚油酸和油酸.     

Physical,nutritional and antioxidant properties of Zimbabwean bambara groundnut and effects of processing methods on their chemical properties

This study examined the physical, nutritional and antioxidant properties of popular Zimbabwean bambara groundnut landraces and the effects of different processing methods on their chemical properties. The physical, nutritional and antioxidant properties of grains of the bambara landraces differed significantly with grain type, and the processing methods investigated had varying effects on the chemical properties of the grains. Bambara had significantly lower protein content than the reference common bean. Protein and carbohydrate content of the grains increased upon dehulling, while tannin (approx. 36%), total phenolic content (approx. 83%) and antioxidant activities (approx. 18%) decreased. Roasting alone seemed to have little or no effect on the nutrient content of the grains, while sifting significantly reduced the phenolic content and antioxidant activity of all the dehulled and roasted samples. The results indicate that roasting bambara grains would be a suitable method as it is relatively more conservative of nutrients and antioxidants than the other methods investigated.     

Supercritical fluid and solid–liquid extraction of phenolic antioxidants from grape pomace: a comparative study

Distilled white grape pomace (Vitis vinifera var. Garnacha) was subjected to extraction by using two different methods: (1) solid–liquid extraction (SLE) employing 96% ethanol and water and (2) supercritical extraction (SFE) by running carbon dioxide coupled with ethanol as a modifier. Higher phenolic concentrations of extracts were attained by SFE (∼400 ppm), doubling those obtained by SLE. In the latter, increasing values of both temperature (from 25 to 50 °C) and contact time (from 30 to 90 min) and lower solvent-to-solid ratios (from 5:1 to 1:1) resulted in an enhancement of extraction efficiency. In SFE, the addition of the modifier (8%) was also found to favour the release of phenolic compounds. Antiradical activity values—evaluated by the ability to scavenge DPPH radicals—were, as general, also higher for SFE extracts, although maximum values reached at were similar (73% inhibition versus 68%). Chromatographic profiles confirmed the diverse nature of phenolic species occurring in extracts obtained from both extraction methods. Extracts from SLE contained more proanthocyanidins, whereas SFE ones contained basically gallic acid, catechin and epicatechin. Protection against oil oxidation assayed with two samples confirmed these results.     

Phenolic acids and flavonoids profiles of extracts from edible wild fruits and their antioxidant properties

In this study, the total phenolic, total flavonoids, phenolic compounds, the mineral content, and antioxidant activity of fruit extracts of seven wild species (Crataegus monogyna Jacq., Prunus spinosa L., Rosa canina L., Hippophaë rhamnoides L., Rubus fruticosus L., Prunus padus, Cornus mas L.) were investigated. The results indicated significant differences (p < 0.05) in the total phenolics and total flavonoids content, between the seven analyzed species. These ranged from 184.69 to 727.29 mg GAE/100 g FW and 17.27 to –165.55 mg QE/100 g FW, respectively. The antioxidant activity found in fruits was not directly affected by the total phenolic content (TPC). This activity was linked to a larger extent to the type of individual phenolic compounds and to a lesser extent to the TPC, because fruits with higher TPC have not always presented the highest values of antioxidant activity. HPLC analysis of methanolic extract showed the presence of phenolic acids (i.e. gallic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, ferulic, sinapic, salycilic, elagic, and trans-cinnamic) and flavonoids (i.e. catechin, epicatechin, rutin, myricetin, and quercetin). Significant differences (p < 0.05) were observed in each individual mineral between fruits from wild flora. The fruits tissues of wild species turned out to be a good source of calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), manganese (Mn), copper (Cu), chromium (Cr), zinc (Zn), and boron (B). The results demonstrated that wild species possessed great potential for food production as sources of bioactive compounds such as phenolic compounds and minerals, for food supplements or functional foods.     

Supercritical fluid extraction of grape seed: Process scale-up, extract chemical composition and economic evaluation

The scale-up of the supercritical fluid extraction (SFE) process for grape (Vitis vinifera L.) seed was studied from the laboratory (0.29 L) to the pilot scale (5.15 L) at 35 MPa and 313 K. The scale-up criterion adopted consisted of maintaining a constant solvent to feed ratio (S/F), and the criterion was successfully used to predict the approximate behavior of the SFE process from the laboratory at the pilot scale for a 17-fold scale-up. Linoleic acid was the major component of the extract; palmitic, stearic and oleic acids were also detected. The economic evaluation showed that it is viable to establish a SFE plant in Brazil for SFE processing of grape seed. From the technical-economic evaluation, for SFE of grape seed at 313 K/35 MPa, an extraction time of 240 min and S/F of 6.6 produced the best relationship between yield and cost.     

超临界CO_2流体萃取琉璃苣籽油及其脂肪酸分析

利用超临界CO2流体萃取技术萃取琉璃苣籽油,考察了萃取压力、萃取温度、萃取时间和CO2流量对琉璃苣籽油出油率的影响,并通过正交试验确定了超临界CO2萃取琉璃苣籽油的最佳工艺条件。研究结果表明,超临界CO2萃取琉璃苣籽油的最佳工艺条件为:萃取压力25 MPa,萃取温度45℃,萃取时间2.5 h,CO2流量45 L/h。在此条件下,出油率为28.08%。气相色谱对琉璃苣籽油的脂肪酸组成分析表明,琉璃苣籽油富含油酸、亚油酸和γ-亚麻酸。     

Effect of extraction solvents on polyphenolic composition and antioxidant, antiproliferative activities of Himalyan bayberry (Myrica esculenta)

Himalyan bayberry (Myrica esculenta) fruit in Indian Himalayan region was evaluated for total polyphenol contents, antioxidant, and anticancer activities in 4 different solvent systems namely 80% each of methanol, acidicmethanol, acetone, and acidic-acetone to ensure the optimum recovery. Himalyan bayberry acidic-acetone (MeAA) extracts showed highest recovery of phenolics, flavonoids, freeradical scavenging, and ferric-reducing activities followed by acetone (MeA), acidic-methanol (MeAM), and methanol (MeM) extracts. Both MeA and MeAA extracts showed potent anticancer activities leading to 70–92% reduction in the viability of C33A, SiHa, and HeLa cells while exhibiting no cytotoxicity towards normal transformed cell lines. The RP-HPLC analysis revealed abundance of gallic acid [793.74 mg/100 g of fruit weight (f.w.) in MeA], myricetin (345.6 mg/100 g f.w. in MeAA), caffeic acid (246.6 mg/100 g f.w. in MeM), catechin (190.181 mg/100 g f.w. in MeAA) while traces of chlorogenic acid (17.67 mg/100 g f.w. in MeAA), transcinnamic acid (5.91 mg/100 g f.w. in MeA), p-coumaric acid (5.84 mg/100 g f.w. in MeA), and ellagic acid (2.21 mg/100 g f.w. in MeA) corroborating the high antioxidant and anticancer activities of Himalyan bayberry fruit extracts.