In vitro Evaluating the Influence of Grape Seed Polyphenol Extract on the Digestibility of Macronutrients

Interaction between dietary polyphenol and proteins including digestive enzymes may result in reduced digestibility of food macronutrients, thus lowering absorption of nutrients that contributing to high energy accumulation in human body. The objective of this study was to investigate the effect of grape seed polyphenol extract （GSPE） on the digestibility of starch, food lipid and food protein by digestive enzymes such as u-amylase, lipase, pepsin and trypsin. The digestion of each substrate was conducted at the optimal pH and temperature of specific enzyme. Bread containing different amount of grape pomace was used as a real food model and its digestion was conducted under simulated digestion condition. Concentrations of reducing sugar, fatty acid and amino acids in enzyme digested mixtures were determined as indicators of starch, lipid and protein digestions, respectively. Results indicate that GSPE significantly inhibited the digestion of starch, cooking oil and casein, but did not inhibit digestion of whey protein and egg white protein. Instead, the digestion of egg white and whey protein by trypsin was moderately enhanced in the presence of GSPE. However, under simulated human digestion condition, the grape pomace in the bread significantly reduced the digestibility of bread starch and protein.

Protective Effects of Polyphenol Extracts from Sea Buckthorn (Hippophaë rhamnoides L.) on Rat Hearts

The objective of present study was to investigate the antioxidative and cardioprotective effects of polyphenol extracts from sea buckthorn (PESB) against myocardial ischemia reperfusion injury (MIRI). PESB was analyzed using HPLC-DAD and their antioxidant activities were evaluated by measuring the intrinsic free radicals cavenging capacity and inhibiting the formation of hydroxyl radical capacity. Experiments on the isolated rat hearts were carried out according to the improved Langendorff retrograde perfusion technology. Coronary effluent of lactate dehydrogenase (LDH) and creatine kinase isoenzyme (CK-MB) activities were analyzed to determine the extent of myocardial injury. Protein expression levels of Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) I and II were measured to evaluate the degree of autophagy. In conclusion, coupled results from both in vivo and in vitro experiments have confirmed that PESB has potential health implications in both prevention and amelioration of MIRI, which may be attributed to the inhibition of autophagy.

Evaluation of the intracellular lipid-lowering effect of polyphenols extract from highland barley in HepG2 cells

Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against obesity.In practical application,the research of food combinations is more significant than a specific food component.This study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid(OA).Five indexes,triglyceride(TG),total cholesterol(T-CHO),low density lipoprotein-cholesterol(LDL-C),aspartate aminotransferase(AST),and alanine aminotransferase(ALT),were used to evaluate the lipidlowering effect of highland barley extract.We also preliminary studied the lipid-lowering mechanism by Realtime fluorescent quantitative polymerase chain reaction(q PCR).The results indicated that highland barley extract contains many components with lipid-lowering effects,such as hyperoside and scoparone.In vitro,the lipase assay showed an 18.4%lipase inhibition rate when the additive contents of highland barley extract were 100μg/m L.The intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mmol/L OA-induced HepG2 cells.The results showed that intracellular TG,LDL-C,and T-CHO content decreased by 34.4%,51.2%,and 18.4%,respectively.ALT and AST decreased by 51.6%and 20.7%compared with the untreated hyperlipidemic HepG2 cells.q PCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγand Fabp4.

Antioxidant and antitumor effects and immunomodulatory activities of crude and purified polyphenol extract from blueberries

The antioxidant and antitumor effects as well as the immunomodulatory activities of crude and purified polyphenol extract from blueberries were investigated. The antioxidant and antitumor effects of the polyphenol extract were measured both in vitro and in vivo, and their effect on the immune systems of CD-1 tumor-bearing mice were also analyzed. In vitro assays demonstrated that blueberry purified polyphenol extract （BBPP） exhibited higher antioxidant activities than blueberry crude polyphenol extract （BBCP）, but the opposite effect was observed in vivo. Both the in vitro and in vivo antitumor activity and the immunity assay showed that BBCP not only inhibited tumor growth, but also significantly improved the immunity of the mice. According to physical and histological studies, the CD-1 tumor-bearing mice treated with the polyphenol extract, especially high doses of BBCP experienced a higher quality of life than the positive control group （treated with cyclophosphamide）. These results indicate that BBCP has significant antioxidant and antitumor activities and that it can enhance the immunity of CD-1 tumor-bearing mice.

Assessment of anti-diabetic activity of peanut shell polyphenol extracts

The present study aimed to evaluate the anti-diabetic property of peanut shell polyphenol extracts （PSPEs）. Diabetic rats were oral-administrated with PSPE at doses of 50, 100, and 200 mg/kg body weight （BW） per day for 28 consecutive days, with metformin （Met） as a positive control. The results showed that, similar to the Met treatment, administration of PSPE caused significant decreases in food intake, water intake, fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, and methane dicarboxylic aldehyde in serum, and significant increases in BW, insulin level, high-density lipoprotein cholesterol, superoxide dismutase, glutathione, and liver gly- cogen. Further, glucose tolerance was markedly improved in the PSPE-treated diabetic groups. Histopathological results showed that PSPE improved cellular structural and pathological changes in liver, kidney, and pancreatic islets. Collectively, the results indicated that the hypoglycemic effects of PSPE on high-fat diet/streptozotocin （HFD/STZ）induced diabetes are comparable to Met, though their exact mechanism actions are still under investigation. Therefore, the current study suggests that PSPE could be a potential health-care food supplement in the management of diabetes.

Anti-oxidant and anti-inflammatory activities of ultrasonicassistant extracted polyphenol-rich compounds from Sargassum muticum

Polypehnol is an important,potentially bioactive component of Sargassum muticum.In this study,ultrasonic assisted extraction of polyphenol-rich substances was performed using a 38%ethanol solution at a solid:liquid ratio of 1:30 at 68℃ for 32min,determined by single-factor and response surface methodology(RSM)optimization.The content of polyphenol was 5.66mg/g in the crude extract.Further extraction showed that the polyphenol mainly distributed in ethyl acetate(SKEE)and water phases(SKEW).The anti-oxidation test by electron spin resonance(ESR)spectrum showed that the SKEE had the strongest scavenging activity on DPPH(1,1-diphenyl-2-picrylhydrazyl)and alkyl radicals.SKEE was shown noncytotoxic but could inhibit the generation of cellular ROS,showing protective effects in H2O2 and AAPHinduced Vero cells and UV-B irradiated HaCaT cells.SKEE also signifi cantly inhibited the release of NO of LPS-induced RAW 264.7 cells.Therefore,the polyphenol-rich extracts in ethanol and ethyl acetate showed excellent anti-oxidant and anti-infl ammatory activities,which is beneficial to the development of high-value bio-substances.

Extraction and Quantification of Total Polyphenol Content in Different Parts of Selected Tea Cultivars

Tea (Cammelia sinensis) is the most widely consumed beverage in the world and has been reported to have unlimited health benefits due to its antioxidant properties. There is a high correlation between polyphenol compounds with antioxidant properties. Tea leaves are a major source of polyphenols. The aim of the present investigation was to determine the approximate level of polyphenols in different other parts of the tea plant to give comparative data on obtaining extracts that can be used to design products through value addition to assist in the prevention of diseases associated with oxidative stress. Twenty-one selected region specific tea varieties were used to obtain roots, flowers, leaves and barks. Leaves were prepared by microwaving and the remaining portions processed as green non-aerated teas and black aerated tea. Roots, barks, flowers were sun-dried and milled. Total polyphenol content was determined by calorimetric method using Folin-Ciocalteu reagent. The obtained results suggest that different parts of tea plant have varying numbers of total polyphenols with microwaved leaves having mean levels at 23.1%, steamed leaves (non-aerated green tea) at 22.37%, aerated leaves at 15.51%, barks at 14.92%, flowers at 10.62% and roots at 1.48%.

Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction（SPE） for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry （UPLC/MS/MS） and multivariate analysis.Several adsorbing materials of SPE（C18,NH2,SAX and OASIS） were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols in tobacco samples after purification.All analytes were separated and determined in 2min.The limit of detection was 0.05 ng/mL.Cluster analysis（CA） and principal component analysis（PCA） were used for the analysis of 4 varieties（flue-cured tobacco,oriental tobacco,sun-cured tobacco and burley） in order to interpret the effect of planting and machining process on the concentration of polyphenols.The different types of tobacco samples could be easily clustered by CA.PCA on the chemical composition of tobacco resulted in two principal components（PCs） that take 84.2% of the total variance.The PCA and CA indicate that the polyphenols can be used for distinguishing tobacco types.

Recovery of polyphenols from camu-camu(Myrciaria dubia H.B.K.McVaugh)depulping residue by cloud point extraction

In this study the potential of cloud point extraction formed by a non-ionic surfactant was used in order to separate polyphenols from industrial residues of camu-camu. The effects of operational conditions of the cloud point extraction(CPE) on the polyphenol recovery and volumetric ratio were investigated. The results showed a maximum recovery of 95.71% that was obtained using 7.0 wt% Triton X-114, native pH(3.25), and 80 wt%polyphenol extract at 30 °C. The use of cloud point extraction was successful to recover the polyphenols from agroindustrial residue since it is a simple as well as of low-cost technique.

Effect of Sodium Carbonate on Extraction by Aqueous Decoction of Total Polyphenols from Crushed and Whole Leaves of Combretum micranthum

Sodium bicarbonate is sometimes used to aid in the extraction of total polyphenols. Its main effect is to increase the pH of the extraction solution. Raising the pH can cause changes in the chemical structure of polyphenols. This can lead to variations in their biological properties, solubility and stability. This work studied the effect of sodium carbonate on the extraction by aqueous decoction of total polyphenols from the leaves of Combretum micranthum. The content of total phenolic compounds in the extracts was estimated by the Folin-Ciocalteu method. The color of the samples was measured using a colorimeter (type: KONICA MINOLTA. Japan) based on the CIELAB color system. The results obtained were subjected to a one-way ANOVA analysis of variance with R software version 3.2.4 Revised (2018) and Minitab-18 software. The results reveal a drop in the concentration of extracted polyphenols proportional to the addition of sodium carbonate, i.e. a drop from 3.30 to 1.04 mg·AG·100 g-1 of extract on whole leaves and 3.921 to 2.551 mg·AG·100 g-1 extract on crushed leaves. On the other hand, the intensity of the coloring of the extracts increases significantly with the addition of sodium carbonate from 0.0 g·L -1 to 0.666 g·L-1.

Ultrasound-assisted extraction of antioxidant polyphenolic compounds from Nephelium lappaceum L.(Mexican variety) husk

Objective: To reach the recovery and identification of antioxidant polyphenolic compounds from Nephelium lappaceum L.(Mexican variety) husk using ultrasound-assisted extraction and liquid chromatography/mass spectrometry as well as the in vitro antioxidant activity. Methods: Rambutan husk extracts were obtained by ultrasound-assisted extraction, mass/volume ratio, water/ethanol percentage and extraction time were evaluated. Once the best extraction condition of polyphenolic compounds was defined, a polyphenolic fraction was recovered using Ambetlite XAD-16. The total content of antioxidant polyphenolic compounds was determined by summation of the total hydrolysable polyphenol and total condensed polyphenol contents. Recovered compounds were identified by FTIR(ATR) spectroscopy and HPLC/ESI/MS. The antioxidant activity was carried out by ABTS, DPPH and lipid oxidation inhibition in vitro methods. Results: In Mexican variety rambutan husk, the total polyphenolic content was 487.67 mg/g, after ultrasound-assisted extraction. According to the HPLC/ESI/MS analysis 12 antioxidant polyphenolic compounds were identified, mostly ellagitannins such as geraniin, corilagin and ellagic acid. The antioxidant activity determined by ABTS, DPPH and lipid oxidation inhibition methods was demonstrated. The main functional groups of the identified compounds were determined by FTIR analysis. Conclusions: It was demonstrated that ultrasound-assisted extraction was effective and allowed the extraction and recovery of antioxidant polyphenolic compounds. Furthermore Mexican variety rambutan husk is an important source for recovering polyphenolic compounds with antioxidant activity, these compounds have potential application for the treatment/prevention of various diseases related to cancer and pathogenic microorganisms.

Effects of Mango Skin or Mango Skin Combined with Paprika Extracts on Production Performance, Egg Quality and Egg Yolk Polyphenols

The phenc, lic compounds found in mango fruit are antioxidants, and contribute to a reduction in the risk of cardiovascular diseases. Mango carotenoids are synthesized in mango fruit during ripening. A major by-product of mango fruit is the skin, which is available after the fruits is consumed or used, particularly in the preparation of jams and fruit juices by the fruit canning industry. The objective of this study was to investigate the effects of dietary mango skin （MS） or mango skin combined with paprika extracts （PE） on production performance, egg quality, and egg yolk polyphenols. Total of 60 44-week-old Boris Brown hens was assigned, based on egg production rate and body weight, to 6 groups （10 birds in each group）. The laying hens were fed a basal diet （control group, 18 CP, 2,800 kcal/kg ME）, a basal diet supplemented with 0.1% PE, 1% or 5% MS, or with a mixture of 0.1% PE with 1% or 5% MS respectively. During the three-week experimental feeding period, the birds had free access to feed and water. Feed consumption was measured weekly and egg production was recorded daily. The results for initial body weight, feed consumption, hen-day production, egg mass, mortality, and final body weight did not indicate any effects of the different treatments （P 〉 0.05）. There were no significant differences （P 〉 0.05） in shell-breaking strength, shell thickness, shell ratio, yolk ratio or Haugh units, except in the case of egg yolk color. Roche yolk color fan scores were better in all experimental groups than in the control （P 〈 0.0001）. The yolk color, yellow index, and ratio of redness to yellowness were greater （P 〈 0.0001） in the 0.1% PE, the 0.1% PE ＋ 1% MS, and the 0.1% PE ＋ 5% MS group than in the 1%, 5% MS, and control groups. Compared with the control, lightness was decreased significantly in the 0.1% PE, the 0.1% PE ＋ 1% MS, and the 0.1% PE ＋ 5% MS groups （P 〈 0.05）, whereas redness was increased significantly in the 0.1% PE, 0.1% PE ＋ 1% MS, and 0.1% PE ＋ 5% MS groups （P 〈 0.0001）. No significant differences among the treatments were observed in either yellowness or egg yolk polyphenols. The results of the present experiment indicate that dietary mango skin or mango skin combined with paprika extracts did not show adverse effects on production performance, egg quality or egg yolk polyphenols. Moreover, supplementation with only mango skin did not enhance egg yolk color.

Study on Processing of Clear Banana Juice Using Hot Water Extraction Method

In this study, the effects of hot water temperature on clarity, total soluble solids, polyphenol oxidase （PPO） and color of banana juice during hot water ex-traction were discussed based on the theory in which heat treatment might induce the pectin and protein in banana pulp to form insoluble products. The results showed the hot water temperature had a significant effect on the formation of insol-uble polymers in banana pulp from pectin and protein. In 75 ℃ water, the pectin and protein in banana pulp were most inclined to form insoluble products. Under this condition, the clarity of banana juice was also highest. The light transmittance at 660 nm was close to 90%. In the banana juice, extracted by 75 ℃ water, the pectin and protein contents were lowest, and they were lower than 7.3 mg/100 ml and 12.9 mg/100 ml respectively. The 75 ℃ water could not inactivate completely the pectin in banana pulp due to its high heat resistance, Therefore, 0.05% L-cys-teine or ascorbic acid needed to be added into banana pulp to inhibit the browning of juice induced by residual PPO.

Total phenolic content,in vitro antioxidant activity and chemical composition of plant extracts from semiarid Mexican region

Objective:To determine the extraction suitable conditions of total phenolic content(TPC) by heat-reflux system,antioxidant activities and HPLC characterization of the aqueous-ethanolic extracts of Jatropha dioica(J.dioica)(Dragon's blood).Flourensia cernua(F.cernua)(Tar bush).Eucalyptus camaldulensis(E.camaldulensis)(Eucalyptus) and Turnera diffusa(T.diffusa)(Damiana).Methods:TPC was evaluated by the well-known colorimetric assay using FolinCiocalteu reagent.The antioxidant activities were assayed by three methods based on scavenging of DPPH,ABTS and by lipid oxidation inhibition.The chemical composition of the extracts obtained was subject to HPLC analysis.Results:TPC in the plant extracts ranged from 2.3 to14.12 mg gallic acid equivalents/g for J.dioica and E.camaldulensis,respectively.The plant extracts of F.cernua,E.camaldulensis and T.diffusa showed similar strong antioxidant activities on scavenging of DPPH and lipid oxidation inhibition.In contrast,J.dioica extracts had lowest potential antioxidant in three assays used.HPLC assay showed the presence of several phenolic compounds in the extracts used.Conclusions:The results obtained suggest that F.cernua,E.camaldulensis and T.diffusa are potential sources to obtain bioactive phenolic compounds with high antioxidant properties which can be used in the factories as antioxidant agents or for treatments in diseases.

Effect of diets supplemented with linseed alone or combined with vitamin E and selenium or with plant extracts,on Longissimus thoracis transcriptome in growing-finishing Italian Large White pigs

Background: Supplementing farm animals diet with functional ingredients may improve the nutritional quality of meat products.Diet composition has been also demonstrated to influence the gene expression with effect on biological processes and pathways.However,the knowledge on the effect of nutrients at the molecular level is scant.In particular,studies on the effects of antioxidants and polyphenols dietary supplementation have been investigated mainly in rodents,and only scarcely in farm animals so far.RNA-Seq with next-generation sequencing is increasingly the method of choice for studying changes in the transcriptome and it has been recently employed also in pig nutrigenomics studies to identify diet-induced changes in gene expression.The present study aimed to investigate the effect of diets enriched with functional ingredients(linseed,vitamin E and plant extracts) on the transcriptome of pig Longissimus thoracis to elucidate the role of these compounds in influencing genes involved in muscle physiology and metabolism compared to a standard diet.Results: Eight hundred ninety-three significant differentially expressed genes(DEGs)(FDR adjusted P-value ≤ 0.05)were detected by RNA-Seq analysis in the three diet comparisons(D2-D1,D3-D1,D4-D1).The functional analysis of DEGs showed that the diet enriched with n-3 PUFA from linseed(D2) mostly downregulated genes in pathways and biological processes(BPs) related to muscle development,contraction,and glycogen metabolism compared to the standard diet.The diet supplemented with linseed and vitamin E/Selenium(D3) showed to mostly downregulate genes linked to oxidative phosphorylation.Only few genes involved in extracellular matrix(ECM)organization were upregulated by the D3.Finally,the comparison D4-D1 showed that the diet supplemented with linseed and plant extracts(D4) upregulated the majority of genes compared to D1 that were involved in a complex network of pathways and BPs all connected by hub genes.In particular,IGF2 was a hub gene connecting protein metabolism,ECM organization,immune system and lipid biosynthesis pathways.Conclusion: The supplementation of pig diet with n-3 PUFA from linseed,antioxidants and plant-derived polyphenols can influence the expression of a relevant number of genes in Longissimus thoracis muscle that are involved in a variety of biochemical pathways linked to muscle function and metabolism.

Rapid and Sensitive Analysis of Eight Polyphenols in Tobacco by Rapid Resolution Liquid Chromatogarphy

A rapid resolution liquid chromatographic (RRLC) method for the determination of eight polyphenols in to-bacco was developed. Polyphenols were extracted from tobacco samples by methanol/ water in an ultrasonic bath, then subjected to clean up by solid phase extraction. The separation was performed on a 50 × 4.6 mm, 1.8 μm ZORBAX Eclipse XDB-C18 column. Compared with conventional HPLC method, the analysis time for eight polyphenols by RRLC method was reduced from 20 to 5 min without sacrificing resolution, and the sensitivity was improved. This method appears simple, accurate and precious. The relative standard devia-tions (RSD) of overall analysis procedure for eight tobacco polyphenols were less than 2% with the recover-ies ranging from 94% to 107%. This method could be applied to the rapid determination of major polyphe-nols in tobacco with satisfactory results.

Alcohols Extraction Process and Content of Active Ingredients in Chinese Northeastern Auricularia auricula

[Objectives] The aim was to study the type and content of alcohol-soluble active ingredients in Auricularia auricula. [Methods]With total yield of alcohol extract as an indicator,the optimal concentrations of ethanol,isopropanol and n-butanol for alcohol extraction of A. auricula powder were determined. The contents of total flavonoids,polyphenols and triterpenoids in three different alcohol extracts of A. auricula,as well as in the alcohol extracts of polysaccharides and melanin extraction residue of A. auricula were determined. [Results] When90% ethanol was used,the yield of alcohol extract of A. auricula was 10. 7%. In the alcohol extract,the contents of total flavonoids,polyphenols and triterpenoids were 5. 68 mg/100 g,0. 43% and 0. 55%,respectively. When 100% isopropanol was used,the yield of alcohol extract was 10. 1%. In the alcohol extract,the contents of total flavonoids,polyphenols and triterpenoids were 4. 84 mg/100 g,0. 66% and 0. 37%,respectively. When 70% n-butanol was used,the yield of alcohol extract was 5. 4%. In the alcohol extract,the contents of total flavonoids,polyphenols and triterpenoids were 4. 07 mg/100 g,1. 68% and 0. 30%,respectively. The yields of ethanol,isopropanol and n-butanol extracts of polysaccharide and melanin extraction residue of A. auricula were 13. 8%,14. 3% and 8. 9%,respectively. In the three kinds of alcohol extracts,the contents of total flavonoids were 8. 28,11. 99,and 12. 38 mg/100 g,respectively; the contents of polyphenols were 0.14%,0. 38% and 0. 75%,respectively; and the contents of triterpenoids were 0. 25%,0. 60% and 0. 58%,respectively. [Conclusions]This study will provide certain reference for the in-depth study and development and utilization of active ingredients in A. auricula.

响应面法优化马齿苋总多酚提取工艺及其抗氧化活性分析

以马齿苋为原料,采用超声辅助提取马齿苋总多酚。以总多酚提取量为指标,在单因素试验的基础上通过响应面法优化提取工艺,并分析马齿苋总多酚的抗氧化活性。结果表明:最佳提取工艺为液料比30:1(mL/g)提取温度45℃、乙醇体积分数60%、提取时间40min,在此条件下马齿苋总多酚提取量为6.89mg/g。抗氧化试验表明,马齿苋总多酚具有较好的抗氧化活性。

Novel drug designing rationale against Brugia malayi microfilariae using herbal extracts

Objective:To explore the effect of herbal polyphenolics on filariasis in vitro.Methods:Two herbal extracts,methanolic extracts of roots of Vitex negundo Linn.（Nirgundi） and leaves of Aegle marmelos Juss.（Beal） in different concentrations ranging from 40-80 ng/mL were tested for their antifilarial activity either alone or in combination with diethyl carbonate（DEC）（300μg/mL） and/or H2O2（0.5 mM）.Results:Combination of DEC and each extract had significant anti-filarial effect.And fractions of both extracts were not effective as crude herbal extract.Conclusions: Such unique pharmacodynamics reported in this study might provide new drug development stratagem against filariasis.

Evaluation of the Antioxidant Activity of Ethanolic Extracts of Some Varieties of Onion

The content of polyphenolic in commercial onions has been determined. The antioxidant activity of their ethanolic extracts, as well as their effects on the oxidation of edible corn oil during accelerated ageing, was studied. Maceration of taxonomically identified commercial vegetable samples, previously peeled and thinly sliced, was carried out at ambient temperature, out of direct light, with occasional agitation and ultrasound, employing 95% ethyl alcohol as the extraction solvent, allowing them to stand for 7 days. The total polyphenolic contents were determined on the filtrated extracts using the Folin-Ciocalteau method. The antioxidant activity was evaluated on emulsions of ethanolic extracts of onion prepared in edible commercial corn oil, using sorbitan monooleate as emulsifying agent. The peroxide values were analyzed using the iodometric method;oxidation induction times were obtained from the peroxide evolution graphs, using the tangent method. Oil samples emulsified with ethanolic onion extracts showed an extension of the induction period. A 7 day ageing study at 45℃ was additionally performed to determine the conjugated dienes on pure commercial corn oil and its emulsions by visible spectrophotometry. The spectral analysis showed an increase of the measured absorbances in oil samples without additives and no change for the oils emulsified with onion extract. An increasing of diene values was observed for corn oil without additives during ageing;no changes in the value were observed in oils emulsified with onion extracts.