Measuring Peroxide Value Research Articles

Measurement of Peroxide Value of Fatty Acids by Near Infrared Reflection Spectra and Analysis of Oxidation Rates

Measurement of Peroxide Value of Fatty Acids by Near Infrared Reflection Spectra and Analysis of Oxidation Rates

Oxidative stability of olive oil–lemon juice salad dressings stabilized with polysaccharides

Lipid oxidation is a major cause of quality deterioration in food emulsions. Polysaccharides used to improve emulsion stability and texture may also affect lipid oxidation. In the present study, the oxidative stability of olive oil–lemon juice salad dressings, stabilized with gum arabic or propylene glycol alginate in admixture with xanthan, was investigated. Oil-in-water emulsions (50:50, v/v) were prepared with lemon juice and extra virgin olive oil and then homogenized at various homogenization rates to form different particle sizes. Keepability was followed by storing at room temperature for 6–8 months and measuring the formation of primary and secondary oxidation products. The shelf life was compared to that of the bulk olive oil. It was shown that the polysaccharides had the ability to inhibit lipid oxidation, probably due to their amphiphilic character (gum arabic and propylene glycol alginate) as well as their ability to induce viscosity increase. Olive oil–lemon juice emulsions were also assessed for consumer acceptance. The panellists were asked to smell the samples and rate them according to rancidity using a four-point (1 = no perception, 4 = extreme) intensity scale. The results were in accordance to those of chemical analysis. Lipid oxidation was not affected by the oil droplet size, as demonstrated by peroxide value measurements and sensory evaluation.

Antioxidant Activity of Origanum majorana L. Oil from Tunisia

The antioxidant activity of Origanum majorana L. oil from Tunisia is tested against two refined vegetable oils (soybean and colza) and an animal fat : lard. The antioxidant effect is confirmed by measuring peroxide values and compared to α-tocopherol. Origanum majorana L. oil showed a high degree of activity at 1000 ppm.

Antioxidant activity of the methanolic extracts of some species of Phlomis and Stachys on sunflower oil

Antioxidant effects of the methanolic extract of Phlomis bruguieri, P. herba-venti, P. olivieri, Stachys byzantina, S. inflata, S. lavandulifolia and S. laxa were tested in sunflower oil stored at 70oC, by measuring peroxide values after regular intervals and compared with rosemary-, green tea- and BHAcontaining samples. The methanolic extracts of P. bruguieri and S. laxa were found to be most effective in stabilizing sunflower oil.

Microencapsulation of fish oil by spray drying--impact on oxidative stability. Part 1

The aim of this study was to investigate the influence of spray drying on oxidative stability of dried microencapsulated fish oil (DMFO) coated with modified cellulose. DMFO samples were obtained by spray drying of prepared emulsions consisted of water solution of modified cellulose and fish oil. Appearance and size of particles were measured by electron microscopy and laser light microsizer. The oxidative stability of samples was evaluated by peroxide value measurements. Additionally the influence of different antioxidant substances on oxidative stability of the fish oil was investigated. It was observed that oxidation changes were much slower in bulk fish oil compared to DMFO. The most important factor determining shelf-life of the product was the access to air. It can be concluded, that the production of fish oil microcapsules by spray drying technique is possible, however its oxidative stability is not improved.

Stabilisation of butter with rosemary antioxidants

The aim of the present study was to test the antioxidant activity of rosemary extract and its mixture with propylene glycol on the stability of fat in butter. Rosemary extract was added at a concentration of 0.02% (w/w) and mixture of rosemary extract with propylene glycol at a concentration of 0.25% (w/w) to the cream before churning. For comparison, control samples without added antioxidant were also prepared and tested. Samples were stored at 4 °C and at 20 °C for 27 days and their peroxide values were determined periodically. The measurement of peroxide values for butter at 60 and 98 °C was also performed. Activity of rosemary extracts was compared with synthetic antioxidant BHT. The rosemary extract and its mixture with propylene glycol exhibited strong antioxidant activity in butter when added to a cream before churning and in an aqueous emulsion system of β-carotene and linolenic acid.

Influence of sodium chloride and its combination with Fe (II) or Cu (II) on the oxidative alteration of butter model systems

The effect of the incorporation of different levels of NaCl at 10.7, 21.4, 46 and 66 g kg -1 , and the combinations of NaCl (10 or 20 g kg -1 ) and Fe(II) or Cu(II) (25 or 50gg -1 ) in model systems of water dispersion in butter fat (WDIBFS) during storage was investigated by measuring peroxide value, p-anisidine index and TOTOX. The results indicated that NaCl at 10.7, 21.4 and 46 g kg -1 levels had a significant retarding effect against fat oxidation during 6 months of storage, while the higher concentration of 66 g kg -1 salt showed a significant prooxidant effect. NaCl significantly (p 0.05) increased the prooxidant effect of Cu(II) in all combinations, whereby the increase was directly proportional to the salt concentration. On the other hand, the addition of NaCl significantly increased the prooxidant effect of Fe(II) ions with no significant differences between the two salt levels (10 and 20 gkg -1 ). Ferrous ions were more effective as prooxidant than Cu(II) ions in the salt free WDIBFS. However, the addition of salt almost canceled the observed differences of the prooxidant influence of Fe(II) and Cu(II) ions.

Phenols, proanthocyanidins, flavones and flavonols in some plant materials and their antioxidant activities

Methanol extracts prepared from five plant materials native to the Mediterranean area, namely olive tree ( Olea europaea) leaf, St. John's wort ( Hypericum perforatum), hawthorn ( Crataegus laevigata), oregano ( Origanum vulgare) and laurel leaf ( Lauris nobilis), were examined for their phenolic components. Total phenolic content was determined by the Folin–Ciocalteu method. The content of proanthocyanidins in acid-hydrolysed extracts was determined spectrophotometrically. The contents of free flavones (apigenin and luteolin) and flavonols (kaempferol, myricetin and quercetin) were determined by HPLC analysis. The time of hydrolysis of flavones, flavonols and proanthocyanidins was optimised. Antioxidant activities of apigenin, luteolin, kaempferol, myricetin, quercetin and of plant extracts were examined. Antioxidative activities were studied in sunflower oil at 98 °C, by measuring peroxide value, and in an aqueous emulsion system of β-carotene and linoleic acid by measuring the absorbance of the sample. Among flavones and flavonols investigated, only myricetin inhibited oxidation of sunflower oil. All other flavones and flavonols showed pro-oxidative activity. Oppositely, in the emulsion system, only apigenin showed pro-oxidative activity while other flavones and flavonols and plant extracts inhibited oxidation of β-carotene.

Antioxidant activities of several Chinese medicine herbs

The antioxidant activity (AA) of ethyl acetate extracts of Caesalpinia sappan, Lithospermum erythrorhizon, Anemarrhena asphodeloides, Paris polyphylla and Illicium verum were tested in refined peanut oil at 60 ± 0.5 °C. The concentrations of the extracts added were 0.20% (w/w). The rate of oxidation was assessed by the measurement of peroxide value (PV) and calculation of such characteristics as induction period (IP), when PV reaches 20 meq kg −1, protection factor (PF), which is the ratio of `IP of the sample with additive' and `IP of the sample without additive', and AA (the ratio of `IP increase of the sample with extract' and `IP increase of the sample with butylated hydroxytoluene'). All of C. sappan, L. erythrorhizon extracts and their combinations were found to be high effective in peanut oil. But the extracts of A. asphodeloides, P. polyphylla and I. verum slightly decrease the formation of peroxides in peanut oil as compared with pure oil.

Isolation and concentration of natural antioxidants with high-pressure extraction

In present work, the purification of crude rosemary extract with supercritical fluids is presented. Carbon dioxide was used as a solvent. The crude extract was prepared from rosemary with conventional extraction process. The supercritical CO 2 extraction of crude extracts was performed at pressures 10 and 20 MPa and temperatures 35 and 60 °C. The best results were obtained at pressure 10 MPa and temperature 35 °C. The content of carnosic acid in the samples before and after high pressure extraction was identified by high performance liquid chromatography. The content of carnosic acid in purified extract is higher compared to crude extract. The antioxidative efficiency of extracts was determined by measuring peroxide value. Activity of purified rosemary extracts is higher compared to crude extracts.

Influence of thermal treatment on tannin content and antioxidation effect of oak acorn quercus cerris extract

The results of investigation of the tannin content in the oak acorn kernel Quercus cerris, qualitative analysis of tannin and antioxidation effect of ethanol extracts of acorn on porcine lipid (prime steam lard) as a substrate are presented in this paper. Experiments were carried out on kernel samples of the domestic oak acorn, from the location Zaglavak, near by the town of Bajina Basta. Tannin content was determined by spectrophotometric procedure using phosphorus Wolframic acid on wave length of 715 nm. Qualitative analysis of tannin included sediment and stain responses as well as tannoform test with formalaldehyde and HCl. Antioxidant effect of ethanol extracts was investigated on fat samples treated at the temperature of 600C in the dark (Schaaloven test). The rate of oxidation was determined by measuring Peroxide value (Pb) and TBA value. The investigated extracts were obtained based on drying of acorn kernel and extracts based on thermal treatment - dry frying of acorn kernel. The obtained results show that dried acorn kernel contains 11.69 % of tannin and thermally treated acorn kernel 8.55%. Qualitative analysis confirmed the presence of gallic acid (pyrogallic, hydrolysing) tannins based on positive general sediment and stain responses on tannins. Ethanol extracts demonstrate antioxidation traits on porcine lipids in trial conditions. Synergistic effect of citric acid with primary anti oxidant was not proved. Thermal treatment of acorn kernel does not reduce the antioxidation activity of extracts.

Quenching Mechanisms and Kinetics of Quercetin in Inhibition of Photosensitized Oxidation of Palm Oil and Linoleic Acid

Effect of 0, 200, 400, 600, 800 and 1000 ppm (wt/vol) quercetin on the erythrosine sensitized photooxidations of palm oil and linoleic acid in methylene chloride containing 100 ppm erythrosine, were studied during storage under 4000 lux fluorescent light for 5 h by measuring peroxide value. Steady-state kinetic approximation was used to determine a quenching mechanism and quenching rate constant of quercetin in the erythrosine-sensitized photooxidation of palm oil and linoleic acid in methylene chloride model system. Erythrosine greatly increased the photooxidation of palm oil and linoleic acid, as was expected. Quercetin was extremely effective in minimizing erythrosine-sensitized photooxidation of palm oil and linoleic. As the concentration of quercetin increased from 0 to 200, 400, 600, 800 and 1000 ppm, the peroxide values of palm oil and linoleic acid decreased significantly (P <0.05). The steady-state kinetic studies indicated that quercetin quenched singlet oxygen only to minimize tire erythrosine-sensitized photooxidation of palm oil and linoleic acid. The calculated total quenching rate of quercetin on erythrosine photosensitized oxidation of palm oil in methtylene chloride was 4.3 x 10 9 M -1 s -1 and total quenching rate of quercetin on erythrosine photosensitized oxidation of linoleic acid in methtylene chloride was 3.2 x 10 9 M -1 s -1 .

Effect of sumach (Rhus coriaria L.) extracts on the oxidative stability of peanut oil.

The antioxidant activities of sumach (Rhus coriaria L.) extracts and butylated hydroxyanisole (BHA) at various concentrations were tested in natural peanut oil stored at 65 degrees C for 35 days. The concentrations (weight/volume) of extracts added into oil were 1.0%, 3.0%, and 5.0%, and those of BHA were 0.1%, 0.3%, and 0.5%. Antioxidant effect was determined by the measurement of peroxide value. After 7 days of storage, BHA and extracts of sumach were active in varying degrees against autoxidation of peanut oil, compared with the control test (P <.01). The sumach extracts generally inhibited the formation of hydroperoxide, as did BHA. After 28 days of storage, antioxidant effects of extracts were significantly decreased when compared with BHA. The decrease in the antioxidant activity of extracts might have resulted from the decrease of polyphenolic constituents. The results showed that high concentrations can enhance the potency of the antioxidant effect of sumach extract.

Oxidative Stability of ω3‐rich Camelina Oil and Camelina Oil‐based Spread Compared with Plant and Fish Oils and Sunflower Spread

ABSTRACT: The oxidative stability of ω3‐rich oil from Camelina sativa and the storage stability of a camelina oil‐based spread were evaluated. Camelina oil was more stable than fish oil and linseed oil, but less stable than sunflower, corn, sesame, and olive oils, indicated by measuring peroxide values (PV), ρ‐anisidine values (AV), total oxidation values (Totox), thiobarbituric acid reactive substances (TBARS), conjugated diene levels (CD), and conjugated triene levels (CT) during storage at 65 °C for 16 d. The camelina oil‐based spread had higher PV, AV, Totox, TBARS, CD, and CT than the sunflower spread but maintained adequate sensory quality for 16 wk of storage at 4 °C or 8 °C.

Effects of β‐carotene and lycopene thermal degradation products on the oxidative stability of soybean oil

AbstractThe relative oxidative stability of soybean oil samples containing either thermally degraded β‐carotene or lycopene was determined by measuring peroxide value (PV) and headspace oxygen depletion (HOD) every 4 h for 24 h. Sobyean oil samples containing 50 ppm degraded β‐carotene that were stored in the dark at 60°C displayed significantly (P&lt;0.01) higher HOD values compared with controls. Lycopene degradation products (50 ppm) in soybean oil significantly (P&lt;0.05) decreased HOD of samples when stored in the dark. PV and HOD values for samples containing 50 ppm of either β‐carotene or lycopene degradation products stored under lighted conditions did not differ significantly from controls (P&lt;0.05). However, soybean oil samples containing 50 ppm of unheated, all‐trans β‐carotene or lycopene stored under light showed significantly lower PV and HOD values than controls (P&lt;0.01). These results indicated that during autoxidation of soybean oil held in the dark, β‐carotene thermal degradation products acted as a prooxidant, while thermally degraded lycopene displayed antioxidant activity in similar soybean oil systems. In addition, β‐carotene and lycopene degradation products exposed to singlet oxygen oxidation under light did not increase or decrease the oxidative stability of their respective soybean oil samples.

ANTIOXIDANT ACTIVITY OF SEAFENNEL (CRITHMUM MARITIMUM L.) ESSENTIAL OIL AND ROSE (ROSA CANINA) EXTRACT ON ANTIOXIDANT ACTIVITY OF SEAFENNEL (CRITHMUM MARITIMUM L.) ESSENTIAL OIL AND ROSE (ROSA CANINA) EXTRACT ON NATURAL OLIVE OILNATURAL OLIVE OIL

The antioxidant effects of seafennel (Crithmum maritimum L.) essential oil and rose (Rosa canina) methanol extract at different concentrations were tested in natural olive oil stored at 60 °C, by measuring peroxide values and free oil acidity after regular intervals. All concentrations of both plant extracts showed antioxidant effect compared with control in experiments. The most effective extracts were 0.4% level of rose. The 0.2% concentrations of rose extract and seafennel oil and 0.4% level of seafennel oil followed in a decreasing order, respectively. The 0.2% level of seafennel oil in olive oil had more effect than those of only 0.02% concentrations of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Acidity values of seafennel oil at the 0.4% concentration were high compared with its 0.2% level. Acidity values of both rose concentrations were found partly similar.

Chemical composition and antioxidant effect of glycosidically bound volatile compounds from oregano (Origanum vulgare L. ssp. hirtum)

Abstract The present work examines the content and chemical composition of the glycosidically bound volatiles from oregano as well as their antioxidative properties. The glycosidically bound volatiles amounted to 20 mg kg−1 in dried leaves and flowers of oregano. Fourteen volatile aglycones were identified with thymoquinone as the major component. Other important aglycones were benzyl alcohol, eugenol, 2-phenyl-ethanol, thymol, 3-hexen-1-ol and carvacrol. It was found that all of the aglycones have an antioxidant effect when tested by measuring peroxide values of lard stored at 60°C. These results were compared to the antioxidative activity of oregano essential oil, pure thymol, thymoquinone and also to α-tocoferol which is well known among natural antioxidant compounds.

EFFECT OF CHOCOLATE COATING ON OXIDATIVE STABILITY OF NORMAL AND HIGH OLEIC PEANUTS

ABSTRACTOxidative stability studies were performed on roasted high‐oleic acid peanuts (HOP‐SunOleic 95) and normal oleic acid peanuts (NOP‐Florunner). Peanuts were dry‐roasted to a Hunter Lab value of approximately 50. Chocolate‐coated peanut bars (6″x4″×1/2″) were prepared using milk chocolate, white chocolate, and reduced‐fat chocolate (containing salatrim). Chocolate bars were stored at 25C and 0.60 water activity (aw). Uncoated peanuts were stored at 0.60 and 0.19 aw at 25C. Samples were removed from storage at 4‐week intervals for peroxide value measurement. Oxidation of peanuts with chocolate coatings were higher than the peanuts that were stored uncoated at the same aw. The peroxide values of NOP were similar for chocolate coated treatments and 0.60 aw control but the 0.19 aw control was 2–4 times higher than the others. Chocolate‐coated peanuts had higher oxidation rates compared to uncoated peanuts.

Preliminary screening of antioxidant activity of some plant extracts in rapeseed oil

The antioxidant activity (AA) of acetone extracts of sage ( Salvia officinalis L.), sweet grass ( Hierocloë odorata Wahlnb.), sea buckthorn leaves ( Hipophaë rhamnoı̈des L.), costmary ( Balsamita major Desf., syn. Chrysanthemum balsamita L.), Roman camomile ( Anthemis nobilis L.), and tansy ( Tanacetum vulgare L.) were tested in refined, bleached and deodorised rapeseed oil at 40°C. The concentrations of the extracts added were in the range from 0.02 to 0.20% (w/w). The rate of oxidation was assessed by the measurement of peroxide value (PV) and calculation of such characteristics as induction period (IP), when PV reaches 20 meq kg −1, protection factor (PF), which is the ratio of IP of the sample with additive with IP of the sample without additive, and AA (the ratio of IP increase of the sample with extract with the IP increase of the sample with butylated hydroxytoluene). Sage and sweet grass extracts were found to be most effective in stabilising rapeseed oil, followed by tansy, Roman camomile, costmary and sea buckthorn in a decreasing order. The IP of rapeseed oil increased with extract concentration. AA's of the extracts added at different concentrations were the following: sage, sweet grass (0.05, 0.1 and 0.2%) and tansy (0.2%) — very high, (PF>3); tansy and Roman camomile (0.1%) — medium (PF=2–2.5), tansy (0.05%), Roman camomile (0.02 and 0.05%) and sea buckthorn (0.1 and 0.2%) — low (PF=1.5–2.0), tansy (0.02%) — very low (PF=1.0–1.5). The extracts of sea buckthorn (0.02 and 0.05%) slightly increased the formation of peroxides in rapeseed oil as compared with pure oil.

Comparison of Natural Polyphenol Antioxidants from Extra Virgin Olive Oil with Synthetic Antioxidants in Tuna Lipids during Thermal Oxidation

Polyphenols extracted from extra virgin olive oil (EVOO) were tested for their ability to inhibit lipid oxidation of canned tuna. Hydroperoxide formation during oxidation was monitored by measurement of peroxide value and decomposition of hydroperoxides by static headspace gas chromatographic analysis of volatiles. In tuna oxidized at 40 and 100 degrees C, 400 ppm of the EVOO polyphenols was an effective antioxidant as compared with 100 ppm of a 1:1 mixture of the synthetic antioxidants butylated hydroxytoluene and butylated hydroxyanisole. However, at concentrations <100 ppm, the EVOO phenolic compounds promoted hydroperoxide formation and decomposition. The EVOO polyphenols were effective antioxidants when added to heated tuna muscle in the presence of either brine or refined olive oil. The oxidation rate in tuna muscle packed in brine was higher than that of tuna packed in refined olive oil. The EVOO polyphenols had higher antioxidant activity in the brine samples than in the refined olive oil. The higher antioxidant activity of EVOO polyphenols in tuna packed in brine may be explained by their greater affinity toward the more polar interface between water and the fish oil system.