Fungal enzymes as a powerful tool to release antioxidants from olive mill wastewater

Enzymatic hydrolysis of olive mill wastewater compounds (OMW) using culture broth of Aspergillus niger, Trichoderma atroviride and Trametes trogii was tested in order to release free simple phenolic compounds having high antioxidant activity. HPLC analysis of treated and untreated OMW indicated the release of large amounts of free hydroxytyrosol (HT). Enzymatic pre-treatment of OMW by A. niger and T. atroviride broth cultures which are rich in β-glucosidase increased the amount of HT respectively from 0.05 up to 1.1 and 0.50 g/L. However, the use of T. trogii broth culture showed an oxidation of phenolic compounds due to its high laccase activity. The ethyl acetate extract of OMW treated by A. niger broth culture with IC₅₀ of 45 μg/mL showed the strongest antioxidant potency compared to untreated OMW with IC₅₀ of 501 μg/mL.     

Antioxidant activity of phenolic fractions in olive mill wastewater

Olive mill wastewater (OMW) contains a substantial amount of valuable antioxidant phenols that can be recovered for industrial application as food additives and pharmaceuticals. The present study was aimed at extracting different phenolic OMW fractions, and determining their antioxidant potential. Five different OMW fractions were obtained using fractionation techniques, their antioxidant potential determined by DPPH, ORAC and a β-carotene bleaching test. The total phenol level ranged between 115 and 170 mg/l. The phenolic compounds present in individual fractions were identified using the HPLC–PAD method, where the main compounds were hydroxytyrosol, tyrosol, caffeic acid, vanillic acid, verbascoside, oleuropein, ferulic acid, and p-coumaric acid. The five OMW fractions showed different antioxidant levels depending on the test used. DPPH test showed that the fraction of alkyl aromatic alcohols (AAAs) was the best with EC₅₀ of 20 mg/l and the pure hydroxytyrosol with 2 mg/l. ORAC test showed that AAA and semi hydrolysed total phenol (s-TP) fractions were significantly better than Trolox when compared to 20 mg/l of Trolox.     

Dietary fiber suspensions from olive mill wastewater as potential fat replacements in meatballs

A dietary fiber containing material, named as alcohol insoluble residue (AIR), was recovered from the olive mill wastewater (OMW). It was separated into different fractions (water soluble and insoluble AIR) and characterized with regard to fiber and ion content. Dynamic rheological tests of the water soluble fraction (WSAIR) were conducted in order to examine its gelling ability. Thereafter, AIR as well as WSAIR were utilized as fat replacement in meatballs together or separately with carrot and starch and compared with regard to the total, water and fat loss or oil uptake during frying of the meatballs. Results indicated that AIR could not be considered as a potential fat replacement in meatballs due to the restricted water holding ability. Nevertheless, WSAIR could be utilized together with carrot fibers as additive in low fat meatballs, since it was able to improve the cooking properties of the product, by restricting the oil uptake and thereby giving rise to meatballs with sustained reduced fat content.     

The effect of heat processing on the functional properties of pectin contained in olive mill wastewater

The purpose of this study was to evaluate the effect of prolonged heat processing (180 min at 50-80 °C) on the functional and rheological properties of pectin, derived from olive mill wastewater (OMW). It was shown that a low temperature blanching of OMW at 60 °C, activates endogenous pectin methyl esterase and promotes demethylation, despite the high concentration of phenols. Activation of the enzyme resulted in enhanced solubilization and subsequent partial degradation of pectin. The induced degradation impaired pectin grade and resulted in loss of gelling functionality. An alternative heating process at 80 °C resulted in negligible enzyme induced degradation of the pectin and improved gelling properties of the recovered material, despite the lower solubilization of the pectin. The obtained results contribute to a better understanding of the temperature effect on pectin functional properties and can be utilized in order to optimize pectin recovery from OMW.     

A study of the recovery of the dietary fibres from olive mill wastewater and the gelling ability of the soluble fibre fraction

A novel method of the recovery of a dietary fibre containing material from olive mill wastewater (OMW) was developed. Extraction was based on thermal treatment with mixtures of ethanol and acids, prior to the isolation of the alcohol insoluble residue (AIR). Different mixtures were tested and the extracted residues were characterized. The maximum AIR recovery accounted 64.8 g/100 g OMW dry matter, while the corresponding total fibre content was 5.1 g/100 g of the AIR. Despite the high potassium (8.4 g/100 g) and the low galacturonic acid content (3.3 g/100 g), AIR was able to form gels after a simple isolation and concentration of the soluble fraction. The soluble fibres were exclusively composed of pectin (93.9 and 6.1 mol/100 mol galacturonic acid and arabinose, respectively) with 59 mol/100 mol GalA degree of methylation. The viscoelastic properties of the gels were evaluated as a function of galacturonic acid content, where the gel rigidity and elasticity was found to increase exponentially with this parameter. A further treatment of the pectin material with citric acid during its concentration, allowed the formation of more rigid, but less elastic gels.     

Isolation of a hydroxytyrosol-rich extract from olive leaves (<Emphasis Type="Italic">Olea Europaea</Emphasis> L.) and evaluation of its antioxidant properties and bioactivity

In this research, a phenol extract of high hydroxytyrosol (OLPE) content was obtained from olive leaves (Olea europaea L.), and subsequently tested under different contexts. The method used to obtain the OLPE basically involved two steps: the use of strongly-acid aqueous steam, generated from 10% HCl (v/v) at 100°C, to directly hydrolyse the native complex phenols from integral olive leaves, and OLPE recovery by liquid–liquid extraction with ethyl acetate. Hydrolysis time was 1 h. Finally, the dried extract was dissolved in distilled water. The OLPE total phenols were determined by Folin–Ciocalteu’s method and by HPLC analysis. Hydroxytyrosol was about 92% of the total phenols present in OLPE, and the yield was about 0.2% on fresh leaves. OLPE showed antioxidant effects on different food lipids and did not inhibit lactic acid bacteria growth; however, it showed cytotoxicity on NIH/3T3 fibroblasts and human umbilical vein endothelial cells at concentrations higher than 0.32 mM (as hydroxytyrosol).     

Spray drying of a phenolic‐rich membrane filtration fraction of olive mill wastewater: optimisation and dried product quality

Olive mill wastewater (OMWW) from 3‐ and 2‐phase mills was subjected to a two‐step membrane filtration process. The obtained reverse osmosis retentate (RO‐R) is a phenolic‐rich coproduct stream, and the reverse osmosis permeate is a near‐pure water stream. A pilot‐scale spray dryer was used for the production of RO‐R powder. The optimum temperature/feed pump conditions were obtained for 3‐phase (150°C/4.4 Hz) and for 2‐phase RO‐R (175°C/3.8 Hz). The powders obtained by spray drying under these conditions were analysed for physicochemical properties, including identification and quantification of phenolic compounds. Protocatechuic acid, 3‐hydroxytyrosol, tyrosol, vanillic acid and p‐coumaric acid were quantified in both RO‐R powders, which show the possibility to obtain a phenolic‐rich powder from an OMWW filtration fraction. This will lead towards better usage of by‐products from olive oil production.     

籽瓜多糖的提取分离及单糖组成的GC-MS分析

用微波辅助萃取技术从籽瓜中提取籽瓜多糖,并用GC-MS分析其单糖组成。依据响应面设计(response surface methodology,RSM)原理,使用SAS(SAS Package)软件的中心组合设计建立提取数学模型,对影响籽瓜多糖得率的提取时间、微波功率、提取温度和料液比4个因素进行优化组合。确定最优提取工艺参数为时间19.5min、温度62℃、料液比(g∶mL)1∶0.9、功率302 W。多糖得率为4.58%。对得到的籽瓜多糖进行了红外扫描,3 408、2928、1 408、1 645.08、1 074 cm-1都出现了糖类的特征吸收峰。GC-MS分析结果表明籽瓜多糖由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖、半乳糖六种单糖组成,摩尔比为4.48∶13.14∶4.16∶7.82∶10.1∶60.3。     

Chemical composition of a protein concentrate from Saccharomyces and its effect on immunologic response]

The content of the main nutrients, as well as amino-acid, fatty-acid and mineral composition of a protein concentrate prepared from yeast-Saccharomyces grown in molasses were studied. It was found that the product contained a significant amount of protein, all essential amino acids, insignificant quantity of lipids in which saturated fatty acids prevailed. The concentrate ash was rich in calcium, phosphorus, magnesium, silicon, iron and other elements. The protein product included into experimental rations during a month produced no significant effect on the B-system immunity and did not induce sensitization.     

响应面法优化麦麸中植酸的提取条件及植酸抑菌效果分析研究

以麦麸为原料,采用盐酸提取麦麸中植酸。在单因素实验的基础上,选择提取时间、提取温度、酸浸液浓度和料液比为自变量,植酸含量为指标,通过响应面法优化植酸提取的工艺条件,建立了植酸提取的二次多项式数学模型,并得到最佳工艺条件。采用牛津杯法研究了其对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌和沙门氏菌的抑菌谱及最小抑菌浓度;探讨了不同浓度、金属阳离子及浓度、温度和有机溶剂对其抑菌效果的影响。结果表明:麦麸中植酸提取的最佳工艺条件为:提取时间2.2h,提取温度40℃,酸浸液浓度1.2mol/L,料液比1∶22(g/m L)。经验证在最佳提取工艺下,植酸的含量为1.215%。植酸提取液对四种细菌均有较好的抑制效果,最小抑菌浓度依次为2.17、2.89、3.61、3.61μg/m L;随着植酸提取液浓度增大,抑菌效果增强;分别与100、200、300mmol/L的氯化钠、氯化钾、氯化镁、氯化钙溶液混合,抑菌效果减弱;与10%(v/v)乙醇、丙二醇、丙三醇等有机溶剂混合后,其抑菌效果明显下降;经0、65、121℃处理后的植酸提取液的抑菌效果无明显变化。      

Optimisation of acid extraction of pectin from sweet potato residues by response surface methodology and its antiproliferation effect on cancer cells

The response surface methodology was employed to study the acid extraction of pectin from sweet potato residues. The effects of extraction temperature, extraction time, solution pH and liquid/solid ratio on yield and galacturonic acid content of pectin were investigated. Experimental data were fitted to quadratic polynomial models and analysed using appropriate statistical methods. The determined optimum conditions were extraction temperature 93 °C, extraction time 2.2 h, solution pH 1.7 and liquid/solid ratio (v/w) 30:1. Under these conditions, the experimental extraction yield and galacturonic acid content of pectin were 5.09% and 70.03% (w/w), which were in good agreement with predicted values, 5.08% and 69.40%, respectively. In addition, sweet potato pectin exhibited remarkable antiproliferation effects on human colon cancer cells HT‐29 and human breast cancer cells Bcap‐37 by 46.64% and 42.64% at 1.00 mg mL^?1 separately, indicating that it could potentially be used as a natural supplement in functional foods.     

The effect of cream and ointment bases on the steady state penetration of permeants through intact skin: the reciprocal of the onset time of a pharmacodynamic effect as parameter of response

To characterize cream or ointment bases for cosmetic or pharmaceutical purposes with regard to their effect on permeant penetration through intact healthy skin, the measurement of the pharmacodynamic response of a suitable model drug incorporated in these bases has been shown to be a promising approach. In general, it may be distinguished between thermodynamic vehicle effects owing to different permeant escaping tendencies from the vehicles and penetration-enhancing vehicle effects resulting from a change of the stratum corneum structure, which manifests itself in an increase of the permeant diffusion coefficient and/or its solubility in this barrier. As the latency time of onset of a pharmacodynamic effect, usually used as reciprocal value, represents a suitable response parameter under certain circumstances, this study was done to further evaluate this parameter with regard to the determination of relative bioavailability and penetration enhancement data obtained from simulated dose- and activity-response curves assuming infinite dose conditions, i.e. zero order penetration kinetics and considering varying lag times of drug penetration. The results indicate that bioavailability and enhancement factors may be determined accurately from the horizontal distance between dose- or activity-response curves of a standard and a test preparation as long as the curves are parallel to each other, as it is the case with uniform lag times of permeant penetration. Non-parallel curves observed with varying lag times indicate an influence of the vehicles on the permeant diffusion coefficient in the barrier. Enhancement factors from these curves may be obtained after determination of the lag times from the plateau region of the curves, subsequent subtraction of these values from the measured latency time data, and finally plotting of the reciprocal data as a function of the drug activity. Enhancement factors then correspond to the inverse logarithm of the horizontal distances between the resulting parallel curves.