Peroxide value

The eect of enzyme addition to the olive paste on the phenolic composition of virgin olive oil has been studied. The experiments were carried out with both Picual and Arbequina cultivars, using the continuous two-phase extraction system at industrial scale and for three consecutive seasons. Phenolic compounds, in particular orthodiphenols, increased their concentration in oils when enzymes were added to the olive paste before the malaxation stage. Among non-orthodiphenols, the lignans 1-acetoxypinoresinol and pinoresinol slightly increased their concentration. In general, the positive eect of enzymes was more marked for Arbequina than for the Picual cultivar. The peroxide index and ``Rancimat'' stability of oils were also positively aected when using enzymes. Besides, wash waters from the vertical centrifuge showed a higher concentration of phenolics when the pastes were treated with enzymes. Therefore, the use of enzymatic formulations during the extraction process of olive oil may not only increase the oil yield but also the nutritional quality of the oil.

In this study, the effects of frying, oven-baking, barbecuing, and smoking on the proximate composition and lipid quality of trout (Onchorhynchus mykiss) were studied. The proximate compositions were affected significantly by all cooking methods. An increase in the lipid content and a decrease in the moisture content were observed in all the cooking methods. A decrease in the protein content was found in barbecued and smoked samples, but not in fried or oven-baked, on dry-weight basis. Regarding the lipid quality, the free fatty acids (FFA, grams of oleic acid per 100-g lipid), peroxide values (POV, meq active oxygen per kg lipid), and thiobarbituric acid values (TBA, mg malonaldehydeper kg fish muscle) were analysed. The FFA contents in fresh, fried, oven-baked, barbecued and smoked trout on wet-weight basis were found to be 8.76, 0.76, 5.05, 0.81, and 9.44-g oleic acid per 100-g lipid, respectively. POV in fried, oven-baked, and barbecued samples increased significantly, while POV in smoked samples decreased significantly. An increase was observed in the TBA value in trout cooked with all methods. The results of this experiment showed that heating accelerates lipid oxidation.

The quality of wild common sole (Solea solea) stored in ice was investigated by chemical (K value, biogenic amines, protein degradation (SDS and SDS-PAGE), pH, peroxide value (PV), free fatty acids (FFA), total volatile basic nitrogen (TVB-N), tiobarbituric acid (TBA) analyses), sensory (raw and cooked fish) and microbiological methods. The quality of common sole decreased on day 16 (fair quality-B) and they were no longer acceptable on day 20 (unacceptable quality-C). When common sole were considered as fair quality (B) by assessors on ~16-18 days, the average K value was ≥ 80%. Among the investigated biogenic amines, histamine was not detected. No major change in the protein profiles of common sole was observed. Sensory, microbial and biochemical results revealed that the shelf life of common sole was approximately ~16-18 days. Among the chemical parameters, the most consistent indicator to measure the change in freshness was K value that showed linear response with storage time.

In this study, the effects of frying, oven-baking, barbecuing, and smoking on the proximate composition and lipid quality of trout (Onchorhynchus mykiss) were studied. The proximate compositions were affected significantly by all cooking methods. An increase in the lipid content and a decrease in the moisture content were observed in all the cooking methods. A decrease in the protein content was found in barbecued and smoked samples, but not in fried or oven-baked, on dry-weight basis. Regarding the lipid quality, the free fatty acids (FFA, grams of oleic acid per 100-g lipid), peroxide values (POV, meq active oxygen per kg lipid), and thiobarbituric acid values (TBA, mg malonaldehydeper kg fish muscle) were analysed. The FFA contents in fresh, fried, oven-baked, barbecued and smoked trout on wet-weight basis were found to be 8.76, 0.76, 5.05, 0.81, and 9.44-g oleic acid per 100-g lipid, respectively. POV in fried, oven-baked, and barbecued samples increased significantly, while POV in smoked samples decreased significantly. An increase was observed in the TBA value in trout cooked with all methods. The results of this experiment showed that heating accelerates lipid oxidation.

The main objective of this study was to assess the quality of bulk palm oil from the point of production (and its distributors) using the critical factors of vitamin A stability and carotenoids (expressed as beta-carotene) in Indonesia. The specific objectives were to analyze the peroxide value (PV), acid value of free fatty acid (FFA) and carotenoids (expressed as beta-carotene) content of unfortified bulk palm oil in Indonesia. The study showed that the quality of initial bulk palm cooking oil, both at the level of manufacturers and distributors, was inconsistent; however, it was still in compliance with the Indonesian standard for cooking oil (SNI 77092012). The PV and FFA range of bulk palm cooking oil analyzed was 0-8.94 meq O2 kg-1 and 0.06-0.23% respectively, and the range of carotenoids content (expressed as beta-carotene) was quite low, only 1.2-3.05 ppm, respectively. The results of this study could be used as the basis of vitamin A fortification in palm oil, since the sta...

In this study, the chemical and sensory qualities of fishburger produced from tilapia (Oreochromis niloticus) were investigated during frozen storage (18 C) over 8 months. The ratios of crude protein, lipid, moisture, crude ash, and polyunsaturated fatty acids in tilapiaburger were found to be 17.82%, 5.29%, 66.68%, 2.56% and 7.95% respectively. At the end of the study, the total volatile basic nitrogen value was found to have fluctuated throughout the storage periods. The highest thiobarbituric acid value was found at the 7th month as 0.142 mg malonaldehyde/kg. The peroxide value was 0.18 meq/kg at the beginning of the storage but increased to 5.03 meq/kg at 6th month of storage and then decreased to 0.82 meq/kg at the 8th month. The level of free fatty acids was 2.73% oleic acid at the beginning but reached 4.14% in the first month of storage and then increased to 5.92% at the end of the storage. pH values ranged between 8.01 and 7.97. At the end of the storage period, sensory quality criteria were scored as quite near those of the fresh samples.

Pengolahan limbah pertanian menjadi bioadsorben arang aktif, merupakan salah satu usaha pemanfaatan limbah pertanian. Penelitian ini bertujuan mempelajari pengaruh konsentrasi NaOH, sebagai aktivator dalam proses pembuatan arang aktif, terhadap kualitas minyak goreng bekas setelah pemurnian. Limbah pertanian yang sudah bersih dan kering kemudian dilakukan karbonisasi di dalam furnace selama 15 menit dengan suhu pembakaran 400oC. Selanjutnya arang diaktivasi dengan merendam dalam larutan NaOH selama dua belas jam. Konsentrasi NaOH yang digunakan bervariasi, yaitu 0,125; 0,25; 0,5; 1 dan 2 N. Setelah itu padatan dicuci sampai netral dan dikeringkan, sehingga diperoleh bioadsorben arang aktif. Minyak jelantah yang sudah dipanasi dicampur dengan bioadsorben. Campuran tersebut diaduk selama satu jam pada temperatur 110oC. Selanjutnya campuran disaring dengan pompa vakum diambil filtratnya yaitu minyak jelantah bersih. Minyak bekas yang sudah bersih, dianalisa kadar asam lemak bebas, bila...

The proximate composition of seeds and main physicochemical properties and thermal stability of oil extracted from Lannea microcarpa seeds were evaluated. The percentage composition of the seeds was: ash (3.11%), crude oil (64.90%), protein (21.14%), total carbohydrate (10.85%) and moisture (3.24%). Physicochemical properties of the oil were: refractive index, 1.473; melting point, 22.60°C; saponification value, 194.23 mg of KOH/g of oil; iodine value, 61.33 g of I 2 /100 g of oil; acid value, 1.21 mg of KOH/g of oil; peroxide value, 1.48 meq of O 2 /kg of oil and oxidative stability index, 43.20 h. Oleic (43.45%), palmitic (34.45%), linoleic (11.20%) and stearic (8.35%) acids were the most dominant fatty acids. Triacylglycerols with equivalent carbon number (ECN) 48 and ECN 46 were dominant (46.96% and 37.31%, respectively). The major triacylglycerol constituents were palmitoyl diolein (POO) (21.23%), followed by dipalmitoyl olein (POP) (16.47%), palmitoyl linoleyl olein (PLO) (12.03%), dipalmitoyl linolein (PLP) (10.85%) and dioleoyl linolein (LOO) (9.30%). The total polyphenol and tocopherol contents were 1.39 mg GAE g -1 DW and 578.56 ppm, respectively. γ-Tocopherol was the major tocopherol (437.23 ppm).

Phytonutrients retained palm olein (PRPOL) was prepared and blended into butterfat at different ratios. The physicochemical characteristics and the phytonutrient composition of blends, as well as its utilization in the preparation of functional chocolate spread were evaluated. The results showed that the redness, yellowness, slip melting point, free fatty acids, peroxide value, iodine value, unsaponifiable matter, diacylglycerol and monoacylglycerol increased while lightness, saponification value, and triacylglycerol significantly decreased upon incorporation of increased quantities of PRPOL into butterfat. The incorporation affected short chain, medium chain and long chain fatty acids content along with variation in the palmitic, stearic, oleic acids content of the blends as compared to butterfat alone. Improvement in carotenoids (6-27 fold), phytotosterols (3-15 fold), tocopherols and tocotrienols (4-17 fold), and squalene (1-6 fold) in blends was observed upon incorporation of PRPOL. Cholesterol level in the blends was reduced (10-50 %) as compared to the butterfat. The blends showed an intermediate solid fat content of PRPOL and butterfat. Moreover, radical scavenging activity of the blends increased with increase in PRPOL quantity. Prepared chocolate spreads showed similar fat, moisture, colour components (L*, a* and b*) and better emulsion stability. The hardness of the spreads was increased upon increasing quantity of PRPOL. The sensory evaluation showed that chocolate prepared by replacing butterfat with 20 % PRPOL had acceptable sensory attributes.

Exploring new sources of natural antioxidants is of great interest to edible oil producers, in line with the toxicological problems generated by the use of synthetic antioxidants. This study assesses the potential of lyophilized Pinot Noir grape pomace extract (GPE) to enhance the sunflower oil stability against thermo-oxidative damage compared to BHT during a prolonged exposure to convective heat at 185 °C. Oil thermo-oxidation was monitored based on specific indices such as peroxide value (PV), para-anisidine value (p-AV), inhibition of oil oxidation (IO), total oxidation (TOTOX) value, conjugated dienes and trienes (CDs, CTs), but also by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), where absorbance ratios A 3009 cm−1/A 2922 cm−1 (RI), A 3009 cm−1/A 2853 cm−1 (RII), A 3009 cm−1/A 1744 cm−1 (RIII) and RIV = A 1744 cm−1/A 2922 cm−1 (RIV) were investigated. GPE showed a significant inhibitory effect on oil thermo-oxidation and this response was co...

Linseed oil characteristics were evaluated to determine whether this oil could be exploited as an edible oil. Petroleum ether extraction of linseeds produced yields of30% (w/w) oil. The chemical composition, including moisture, total oil content and ash, was determined. Iodine value, saponification value, acid value and peroxide value of obtained linseed oil was analyzed. The fatty acids composition was analyzed with GC-MS method according to AOAC standards. Linseed oil was found to contain high levels of linolenic (53.21%) followed by oleic (18.51%), and linoleic (17.25%), while the dominant saturated acids were palmitic (6.58 %) and stearic (4.43%).

Aims: This study was aimed to investigate the physicochemical properties and fatty acids composition of Mangifera indica L. seed kernel oil; in addition to investigating the effect of solvent type and extraction duration on extracts properties. Study Design: Extraction of Mangifera indica L. seed kernel oil in different trials under the same conditions using two different solvents for different time of extraction, and determining their physicochemical properties and fatty acids constituents.

This study assesses the capacity of a Fourier transform near-infrared (FT-NIR) spectrometer operating in the range 4500-12 000 cm (833.33-2222.22 nm) to provide quantitative predictions for the parameters of acidity (AV), p-anisidine (pAV), total polar materials (TPM), peroxide value (PV), and oxidative stability index (OSI). 562 samples of frying oil were analyzed from 14 distinct types of oil. The calibrations obtained accounted for 96%, 95%, 99%, 92%, and 91% of the AV, pAV, TPM, PV, and OSI variations in the study set and the similarity between the standard error of laboratory (RMSEP) values and the reference method errors (RMSEL), enabling the authors to conclude that NIR technology has the capacity to replace traditional methods in thermo-oxidative degradation studies in frying oils.

The evolution of some quality markers of baobab (Adansonia digitata L.) was studied. Baobab oil extracted by pressing was packaged in 30 mL non-amber glass bottles and stored at different temperatures: 20˚C, 30˚C and 45˚C. The physicochemical parameters (acid, peroxide, iodine, saponification, refraction and color indices) were determined during three months' storage. A significant 5% increase in acid, peroxide and saponification value was observed over time. However, the iodine value decreased. The yellowing and refractive index remained stable while storage at 45˚C caused the most significant changes in chemical parameters. The results obtained show that oils stored at 20˚C had the lowest acid (2.42 ± 0.26 mg KOH/g) and peroxide (0.82 ± 0.25 mEqO 2 /Kg) value after three months of follow-up.

Biji tanaman pala (Myristica fragrans Houtt.) yang terdiri dari bagian tempurung memiliki kandungan hemiselulosa, selulosa dan lignin, serta bagian biji mengandung fixed oil atau mentega pala dimana mayoritas penyusun senyawa tersebut adalah atom karbon. Tujuan penelitian ini adalah untuk mengetahui waktu terbaik proses pemurnian minyak jelantah menggunakan karbon yang berasal dari biji pala. Penelitian ini menggunakan metode karbonisasi dengan suhu tinggi untuk mendapatkan karbon aktif sebagai adsorban. Rendemen karbon aktif yang diperoleh sebesar 24.40%. Hasil karakterisasi karbon berupa bagian yang hilang dari pemanasan sebesar 7.14%, kadar air sebesar 2.00%, kadar abu sebesar 1.00%, dan daya serap terhadap I2 sebesar 847.64 mg/g. Variabel penelitian yang digunakan yakni lama waktu perendaman karbon aktif dalam minyak jelantah selama 8,16,24,32,40, dan 48 jam. Karakteristik hasil pemurnian minyak jelantah yang diamati antara lain warna kuning, berbau normal, bilangan asam sebesar...

Fortification of foods is a well sighted path for solving nutritional problems in developing society. Common vegetable oil such as sunflower oil was utilized for fortification with Vitamin A. The objective of this study was to fortify the sunflower oil with vitamin A as per World Food Program (2011) guideline and to test the stability of vitamin A during different storage, packaging and deep fat frying conditions. The fortified oil was analyzed for a period of 5 months for its physicchemical properties under various study conditions. The result of this study showed that vitamin A added to oil stored at room temperature under dark condition was stable for the entire study period. The retention of vitamin A in deep fat fried sunflower oil was found to be 85%, 68%, 49%, 38%, 19% and 7% for first, second, third, fourth, fifth and sixth frying, respectively. Further from the study was understood that there was no significant difference in the physic-chemical properties of the fortified oil during the study period. As a whole, the results of this study clearly revealed that Vitamin A added to refined oil remains stable during commonly adopted storage conditions while there is a significant reduction in vitamin A content during frying cycle.

Fortification of foods is a well sighted path for solving nutritional problems in developing society. Common vegetable oil such as sunflower oil was utilized for fortification with Vitamin A. The objective of this study was to fortify the sunflower oil with vitamin A as per World Food Program (2011) guideline and to test the stability of vitamin A during different storage, packaging and deep fat frying conditions. The fortified oil was analyzed for a period of 5 months for its physicchemical properties under various study conditions. The result of this study showed that vitamin A added to oil stored at room temperature under dark condition was stable for the entire study period. The retention of vitamin A in deep fat fried sunflower oil was found to be 85%, 68%, 49%, 38%, 19% and 7% for first, second, third, fourth, fifth and sixth frying, respectively. Further from the study was understood that there was no significant difference in the physic-chemical properties of the fortified o...

Aim: Certain edible plant sources contain vegetable oils that have been under-exploited both commercially and in research. This study aimed to determine the physicochemical properties, fatty acids composition, and antioxidant potential of the oil from the seed kernels of Telfairiapedata, which are used as food by the local population of Tharaka-Nithi County in Kenya. Materials and Methods: Telfairia pedata seeds were collected from farmers in the county of Tharaka-Nithi, Kenya. n-Hexane was used to extract the oil via soxhlet extraction. Standard laboratory protocols were used to characterize the oil’s physicochemical properties, while fatty acids composition and antioxidant potential were characterized using gas chromatography mass spectrometry and 2, 2-diphenyl-1-picrylhydrazyl assay, respectively. Results: The seed kernels of Telfairia pedata yielded more than 66% of oil. The oil’s physicochemical properties were found to be within the Food and Agriculture Organization set limits...

Date palm (Phoenix dactylifera) is considered to be one of the oldest cultivatable crops. The date palm kernels (DPK) considered a waste product of many date processing plants producing pitted dates, date syrup and date confectionery. Direct consumption of ...

The aim of the study was to assess the antioxidant effect of concentrated oil macerate of sage (M) as a “green extract” in inhibiting the oxidation of Fish Oil (FO). In the homogenization-assisted maceration process, FO was used as a solvent for the sage active substances to produce M, which was then added to FO (25% w/w) and evaluated for its effect by monitoring the level of oxidation during refrigerated and room temperature storage. The macerate also examined polyphenols, plant pigments, DPPH antioxidant potential, oxidation level and sensory quality. It was shown that the maceration process made it possible to obtain aromatized M, containing polyphenols (carnosic acid, carnosol) and pigments, but with an increased level of peroxides, free fatty acids, compared to the control oil. M showed antioxidant properties and inhibited FO oxidation. It showed the best efficiency in FO during refrigerated storage, in the third month it reduced the level of peroxides by about 9 times, compar...

From ancient times the natural plant Cornelian cherry is used for various purposes. The healing properties of Cornelian cherry suit the human body and give it the necessary vitamins, acids, and everything else it needs for the body to function normally and healthily. Due to its antioxidant, antiallergic, antimicrobial, and antihistamine properties, it is increasingly used as a dietary supplement, as well as for medical and pharmaceutical purposes. In addition to the fruit of the Cornelian cherry, in the past, the oil of Cornelian cherry seeds was used, the content of which can be up to 30%. However, the data available in the literature are scanty and do not show true values because the oil content depends on many factors, such as the geographical origin of the Cornelian cherry, the harvest period, varieties, etc., which also affects the oil content in the seeds. Therefore, the aim of this study is to determine the average oil content of Cornelian cherry seeds, and to determine the o...

The aim of the investigation was to determine the changes in fatty acids profile and chemical quality indices of Red Tilapia fillets during frozen storage at -18°C. The fish were filleted by hand. The prepared fillets were then placed to the polyamide pouches and stored at -18°C for 150 days. Fatty acid profile, sensory properties and chemical quality indices were determined for a five month period. Results showed that 29 fatty acids were identified in the fresh and frozen samples. Polyunsaturated fatty acids (PUFA) were found higher than saturated fatty acids (SFA) in fresh samples but after 150 days of frozen storage this ratio became reverse. Oleic acid and Linoleic acid were the major MUFA (mono unsaturated fatty acids) and PUFA in fresh and frozen samples, respectively. The ratio of n3/n6 decreased from 0.59 to 0.49. The thiobarbituric acid value (TBA. Mg malondialdehyde/kg) increased significantly (p<0.05) throughout the storage time from 0.03 to 1.26 . Peroxide value (PV), Total volatile bases (TVB-N) and pH value also increased but were well within the limit of acceptability.

This study evaluates the combined efficiency of whey protein isolate (WPI) with maltodextrin (MD) and gum arabic (GA), as a delivery system for encapsulating Citrus reticulata essential oil (CEO). The wall materials blended at different rates were produced to obtain seven formulations of nanocapsules (NCEO), namely NCEO-GA, NCEO-MD, NCEO-WPI, NCEO-GA/MD, NCEO-GA/WPI, NCEO-MD/WPI, and NCEO-GA/MD/WPI. The interaction between CEO and WPI was simulated by molecular docking. Findings showed that the physicochemical characteristics and storage stability of formulations containing WPI were considerably improved. The NCEO-GA/MD/WPI formulation demonstrated the optimum values of encapsulation efficiency (92.08%), highest glass transition temperature (79.11 °C), high crystallinity (45.58%), high thermal stability (mass loss at 100 °C &lt; 5%), and also had the highest antioxidant activity and lowest peroxide value after storage. This study demonstrated that combining WPI with MD and GA, as wa...

The organic olives from Çine-Aydın (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO 2 /kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K 232 and K 270 values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K 232 value. Ozonated water washes had almost no effect on fatty acid composition.

Purpose -The purpose of this paper is to determine the peroxide value (PV), p-anisidine and total oxidation value (TOTOX) values of imported edible oils in Iran. Design/methodology/approach -A total 196 oil samples of different origin and types (corn, olive, canola and grape-seed oil) were collected randomly from Boushehr port of Iran and a total 27 oil samples were also collected from frying pans used to deep-fry local food items at different restaurants in Boushehr city. Findings -The PVs ranged from 1. 38-13.74, 3.90-20.00, 0.83-2.99, 0.67-11.95 and 0.00-9.96 mequiv/kg found in refined olive oil, virgin olive oil, canola oil, grape-seed oil and corn oil, respectively. The results showed that PVs of 18.37 percent of imported oil and 62.96 percent of frying oils from restaurant exceeded the maximum acceptable limits set by Institute of Standards and Industrial Research of Iran (ISIRI) (2-20 mequiv/kg for different types of oils). P-anisidine value ranged from 0.89-27.56 mequiv/kg in imported oils and 2.21-30.76 mequiv/kg found in frying oil from restaurants. The TOTOX value increased linearly with peroxide values and p-anisidine values. It ranged from 0.89-76.62. Originality/value -Fried foods are very common in Iranians' diet. A major portion of the edible oils in Iran are imported from other countries through Boushehr port. ISIRI has set maximum acceptable limit for PVs in different oils imported to the country. The possible effects of storage on oil oxidation are the original criteria of this research. The results of the study indicate that inappropriate storage of edible oils and their use in frying applications at restaurants facilitate oil oxidation and deterioration.

preventive action on certain diseases, such as atherosclerosis and cancer. The chemical composition of Virgin Olive Oil (VOO) changes varying on particular combinations of factors as variety, applied cultivation techniques 6) , climate, geographical site 7) , and ripening stage of olives 8) . The differentiation of olive oils according to the ripening degree is likely to be of an utmost significance for understanding how biologically active components accrue for the duration of olive development to detect the relationship between the ideal harvest time and the optimum oil quality. Overall, during the ripening period, many metabolic processes happen in olives with the ensuing changes on the chemical structure and concentration of some compounds. These

Cocozone Oil (CCO) is one of the ozonated oils, obtained by the ozonation process of Virgin Coconut Oil (VCO), that can be used as a material for skin care products. The purpose of this study was to determine: (1) the optimum time and ozone dose for CCO synthesis from VCO using ozonation; (2) the changes in physico-chemical properties of the oil; (3) the change in saturated-unsaturated fatty acids content and the existence any new substances in the CCO. The ozonation of VCO was carried out for 25 hours, with monitoring at the intervals of 4, 8, 12, 16, 20 and 25 hours, at a constant temperature (25 °C) with an ozone flow of 0.25 g/hr. From this study it can be concluded that: (1) The optimal time or dose of ozone required for the synthesis of CCO from VCO through the ozonation process was 25 hours or equivalent to 0.0208 gr O3/ml VCO, (2) Physico-chemical characteristics of the CCO produced: resulting acid value (AV) was 2.71 mg/gram i.e. an increase of 630%; the peroxide value (PV) obtained was 238,77 mgrek/kg i.e. increase of 3,453 %; the Iodine value (IV) was 0 (zero) i.e. a decrease of 100%; and, the viscosity was 13.30 centipoice i.e. it rose 116%; (3) the total content of saturated fatty acid increased by 3.34% whereas the unsaturated fatty acid decreased by 98.83; and based on the analysis results of 13 C and 1 H NMR spectra, the resultant CCO contains a new substance, that is aldehydes.

BACKGROUNDFats and oils represent the most concentrated source of energy available to animal nutritionists and form an expensive part of the diet. Thorough understanding of lipid quality and composition are required for efficient and precise diet formulation. Therefore, 724 samples of commercially available fats and oils were assessed for fatty acid profile, oxidation status and energetic value as per the Wiseman equation, with consideration of a correction factor K, which is based on the presence of the energy diluting compounds moisture, impurities and unsaponifiables.RESULTSEnergy diluting compounds were widespread across fat types and sources. Average MIU (moisture, insoluble impurities and unsaponifiable matter) presence in individual oils was 5.1–28.1 g kg−1. Using the adapted Wiseman equation presented in the current paper, which reflects the energy diluting potential of MIU, the calculated energy values of fats and oils is reduced by up to 46% in extreme cases compared to th...

A study on the photocatalytic detoxification of aflatoxins in Sudanese peanut oil was performed using titanium dioxide (TiO 2 ) that was immobilized on a glass support as the photocatalyst and a 500 W high-pressure lamp (with emitted UV of 920 W/m 2 and visible of 2000 W/m 2 ) as the light source. The study was performed on naturally contaminated peanut oil obtained from two different irrigation systems in Sudan. Aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) were identified, quantified and detoxified, whereas aflatoxin G1(AFG1) and aflatoxin G2 (AFG2) were not detected. The results showed that photocatalysis was better than photolysis, whereby ≥ 99.4 % of AFB1 and ≥ 99.2 % of AFB2 were effectively detoxified within 4 minutes of irradiation at room temperature. In addition, there was no significant changes in the physicochemical characteristics of the peanut oil after treatment, these include fatty acids composition, peroxide value, saponification value, acid value, free fatty acids, iodine value, moisture and volatile matters as well as the refractive index. Furthermore, the TiO 2 photocatalyst was also reusable for up to ten cycles of application, thus offering a practical way to detoxify aflatoxins in peanut oil.

Peroxide values, TBA numbers and chromatic parameters of edible vegetable oils (olive, sunflower, corn oils) thermally oxidised (75°C, 100°C, 180°C) during 5 days were determined. For calculating chromatic parameters the recommended standard CIE methods and several simplified methods were employed. With olive oil a remarkable change in spectral characteristics occurred as the temperature and time of heating were increased. Thermal autoxidation, as assessed by peroxide value and TBA number, was only observed at 75°C (Schaal oven test). In none of the three types of vegetable oil was the dominant wavelength modified during the course of the heating process. Luminosity and hue angle showed slight increases in olive and sunflower oils. Colour saturation underwent a remarkable decrease in olive oil. From a comparison and a correlation study it is concluded that the simplified methods could be applied only for certain chromatic parameters and types of vegetable oil. For a comprehensive st...

In this study, the oxidation stabilities of organic hazelnut oils (OHO) were compared to conventional hazelnut oils (CHO). For this purpose, oxidation parameters such as peroxide value (PV), free fatty acid (FFA), anisidine value (AV), volatile lipid oxidation compounds (VLOC), fatty acid composition, and total antioxidant capacity (TAC) of the hazelnut oil samples were investigated under conditions of accelerated storage. At the beginning of storage, OHO had lower PV, higher AV, TAC and linoleic acid content than CHO and similar FFA, VLOC, palmitic, stearic, and oleic acids contents to CHO. As expected, PV, FFA and AV increased in OHO and CHO during storage, while TAC decreased. No significant difference between OHO and CHO was observed in terms of FFA, TAC, palmitic and stearic acid contents at the accelerated storage condition. When compared to CHO, OHO showed lower oleic acid and higher linoleic acid at the end of storage. During storage, the highest AV and PV were determined in OHO. Results reveal that OHO has lower oxidation stability than CHO. According to these results, it can be recommended to consume the OHO without being exposed to long-term oxidation.

Headspace solid phase microextraction chromatography (HS-SPME/GC) was evaluated as a tool in determining the rate of oxidation in oxidized soybean oil samples by measuring the production of hexanal as a secondary major volatile breakdown product of linoleic acid. Samples of the headspace taken from sealed 20 mL vials, incubated 30 min at 50 °C followed by 5 min adsorption, were injected into a gas chromatograph with 2 min thermal desorption. In applying SPME, different analytical conditions were evaluated. The linearity of response of the volatiles for the HS-SPME/GC procedure using a carboxen-polydimethylsiloxane fiber was determined from 3 g of mineral oil spiked with a hexanal standard solution at different levels. Using the optimized extraction conditions, an R value close to unity (R = 0.999) was found, and the repeatability (n = 11) was 6.31%. The results indicated that hexanal is linearly related to peroxide value (PV) only intermediate PV ranges (10-18 meq/kg). The study also showed that HS-SPME/GC procedure was a simple and reproducible method for the analysis of hexanal in the HS of commercial soybean oil samples, and is useful as a quality control and research tool for the evaluation of flavor quality and shelf life of vegetable oils.

Previous work in our laboratory demonstrated that soybean oil oxidation, expressed as PV, can be determined using NIR transmission spectroscopy as an alternative to the official AOCS iodometric titration method. In the present study, a comparison of four peroxide analytical methods was conducted using oxidized soybean oil. The methods included the official AOCS iodometric titration, the newly developed NIR method, the PeroxySafe™ kit, and a ferrous xylenol orange (FOX) method, the latter two being colorimetric methods based on oxidation of iron. Five different commercially available soybean oils were exposed to fluorescent light to obtain PV levels of 0-20 meq/kg; periodic sampling was done to ensure having representative samples throughout the designated range. A total of 46 oil samples were analyzed. Statistical analysis of the data showed that the correlation coefficient (r) and standard deviation of differences (SDD) between the standard titration and NIR methods were r = 0.991, SDD = 0.72 meq/kg; between titration and the PeroxySafe™ kit were r = 0.993, SDD = 0.56 meq/kg; and between the standard titration and FOX method were r = 0.975, SDD = 2.3 meq/kg. The high correlations between the titration, NIR, and PeroxySafe™ kit data indicated that these methods were equivalent.

Headspace solid phase microextraction chromatography (HS-SPME/GC) was evaluated as a tool in determining the rate of oxidation in oxidized soybean oil samples by measuring the production of hexanal as a secondary major volatile breakdown product of linoleic acid. Samples of the headspace taken from sealed 20 mL vials, incubated 30 min at 50 °C followed by 5 min adsorption, were injected into a gas chromatograph with 2 min thermal desorption. In applying SPME, different analytical conditions were evaluated. The linearity of response of the volatiles for the HS-SPME/GC procedure using a carboxen-polydimethylsiloxane fiber was determined from 3 g of mineral oil spiked with a hexanal standard solution at different levels. Using the optimized extraction conditions, an R value close to unity (R = 0.999) was found, and the repeatability (n = 11) was 6.31%. The results indicated that hexanal is linearly related to peroxide value (PV) only intermediate PV ranges (10-18 meq/kg). The study also showed that HS-SPME/GC procedure was a simple and reproducible method for the analysis of hexanal in the HS of commercial soybean oil samples, and is useful as a quality control and research tool for the evaluation of flavor quality and shelf life of vegetable oils.

NIR spectroscopy was used successfully in our laboratory to monitor oxidation levels in vegetable oils. Calibration models were developed to measure PV in both soy and corn oils, using partial least squares (PLS) regression and forward stepwise multiple linear regression, from NIR transmission spectra. PV can be measured successfully in both corn and soy oils using a single calibration. The most successful calibration was based on PLS regression of first derivative spectra. When this calibration was applied to validation sample sets containing equal numbers of corn and soy oil samples, with PV ranging from 0 to 20 meq/kg, a correlation coefficient of 0.99 between titration and NIR values was obtained, with a standard error of prediction equal to 0.72 meq/kg. For both types of oil, changes occurred in the 2068 nm region of the NIR spectra as oxidation levels increased. These changes appear to be associated with the formation of hydroperoxides during oxidation of the oils.

Electronic nose and SPME-GCMS were used to monitor the autoxidation in long chain polyunsaturated fatty acid (LCPUFA)-enriched lipid microparticles produced by spray congealing with ultrasonic nebulization, during storage at 20 • C up to 6 weeks with sufficient air supply and limited air supply. Conjugated dienes and peroxide value as well as secondary lipid oxidation products were analysed to follow the course of autoxidation. Principal Component Analysis evidenced that only MOS sensors but not MOS-FET sensors contributed to the discrimination of the samples and facilitated the ability of the electronic nose to distinguish the LCPUFA-enriched lipid microparticles into two groups according to the different oxidative status. The selected MOS sensor responses correlated well with quantitative dominating volatile compounds (propanal and hexanal) and with volatile compounds which have been associated with fishy and rancid off flavour (1-penten-3-one, 1-penten-3-ol, 2,4-heptadienal and 2,6-nonadienal). Bread mix supplemented with the LCPUFA-enriched microparticles was analysed as an example for a LCPUFA supplemented food. Data from the present study indicate that the electronic nose can be used as a sensitive tool to evaluate the lipid oxidative status of LCPUFA-enriched microparticles. In supplemented foods like bread mix, matrix-related changes, which occur in supplemented and non-supplemented samples, make a clear distinction more difficult.

The effect of processing on physicochemical properties of freshly extracted crude groundnut oil was determined. Crude groundnut oil was extracted following the traditional method and half of it was processed as done industrially. Chemical properties [acid value, free fatty acid, peroxide value, saponification value, ester value, iodine value, total phenol (TP), p-Anisidine value, total tocopherol (TT), and total antioxidant capacity (TAC) and thiobarbituric acid reactive species (TBARS)] and physical properties (refractive index, surface tension, smoke point, flash point, viscosity and specific gravity) were determined following the AOAC and other standard methods. Analysis of the results indicated that the processing of the crude groundnut oil, although improved the physical appearance and reduced free fatty acid by 56% hence, could improve its stability but it also compromised the levels of antioxidant compounds such as tocopherols in the oil that reduced by 16.4%. TAC, an antioxi...

The effect of processing on physicochemical properties of freshly extracted crude groundnut oil was determined. Crude groundnut oil was extracted following the traditional method and half of it was processed as done industrially. Chemical properties [acid value, free fatty acid, peroxide value, saponification value, ester value, iodine value, total phenol (TP), p-Anisidine value, total tocopherol (TT), and total antioxidant capacity (TAC) and thiobarbituric acid reactive species (TBARS)] and physical properties (refractive index, surface tension, smoke point, flash point, viscosity and specific gravity) were determined following the AOAC and other standard methods. Analysis of the results indicated that the processing of the crude groundnut oil, although improved the physical appearance and reduced free fatty acid by 56% hence, could improve its stability but it also compromised the levels of antioxidant compounds such as tocopherols in the oil that reduced by 16.4%. TAC, an antioxi...

Fortification of vegetable oil with vitamin A is considered a cost-effective and simple to implement strategy, but the stability of vitamin A remains a limiting factor. To account for losses of vitamin A, oil producers add an overage. Optimizing the amount of this overage can result in considerable savings for industry and government while ensuring a supply of adequately fortified oil to consumers. To estimate vitamin A losses in oil with different chemical characteristics. Samples of fortified oils with different chemical characteristics were collected from two Egyptian companies (oil A and B) and stored for 1 month. Vitamin A levels were analyzed periodically during storage to determine losses over time, and peroxide values were determined. Fortified oil B, with a high peroxide value (5.8 mEq/kg), exposed to sunlight had significantly higher losses of vitamin A after 4 weeks than fortified oil A, with a low peroxide value (0.4 mEq/kg): 31.1% vs. 19.7% (p &lt; .001), respectively. ...

Unbranded palm cooking oil has been fortified for several years and can be found in the market with different oxidation levels. This study aimed to investigate the stability and shelf life of unbranded, bulk, vitamin A-fortified palm oils with the most commonly observed oxidation levels in Indonesia. Three types of cooking oils were tested: (i) cooking oil with a peroxide value (PV) below 2 mEq O2/kg (PO1); (ii) cooking oil with a PV around 4 mEq O2/kg (PO2); and (iii) cooking oil with a PV around 9 mEq O2/kg (PO3). The oil shelf life was determined by using accelerated shelf life testing (ASLT), where the product was stored at 60, 75 and 90 °C, and then PV, free fatty acid and vitamin A concentration in the oil samples were measured. The results showed that PO1 had a shelf life of between 2-3 months, while PO2's shelf life was a few weeks and PO3's only a few days. Even given those varying shelf lives, the vitamin A loss in the oils was still acceptable, at around 10%. However, the short shelf life of highly oxidized cooking oil, such as PO3, might negatively impact health, due to the potential increase of free radicals of the lipid peroxidation in the oil. Based on the results, the Indonesian government should prohibit the sale of highly-oxidized cooking oil. In addition, government authorities should promote and endorse the fortification of only cooking oil with low peroxide levels to ensure that fortification is not associated with any health issues associated with high oxidation levels of the cooking oil.

The objective of present study was to evaluate the vegetable oils used for commercial frying of chicken and samosa, an indigenous fried product of Pakistan. Physiochemical analysis of the excessively used vegetable oils showed that refractive index and specific gravity was affected non significantly as a result of frying operation. However, acid value, saponification value, peroxide value, free fatty acids and total polar compounds were significantly lower (p<0.05) in the oil used before frying as compared to the values recorded after frying operation. The oils, before and after frying of samosa and chicken exhibited the iodine values in the range of 87.9±0.07-120.5±11 and 86.5±1.03-118.4±10.45, respectively. Stearic acid, palmitic acid and oleic acid content were found to be lower in oils before frying than after frying in both the products, however, linoleic acid and linolenic acid indicated higher values in oil before frying than after frying. Total polar compounds (TPC) were shown to be significantly lower in oil before frying than after frying of samosa and chicken. TPC increased from 2.3±0.25 to 32.2.9±0.83 and 2.30±0.30 to 29.18±0.96, respectively in oils used for samosa and chicken. The higher values of TPC might be due to excessive number of frying and use of low quality oil. The study concluded that the changes in the chemical profile of excessively used oil were severe enough to cause several health hazards and rendered oils unfit for human consumption.

Palm oil is one of the important commodities of Malaysia and is superior for frying due to its high oxidative stability and high content of unsaturated fatty acids. The quality of frying oil will decrease with time and repeated cycles of frying, and may subsequently affect the safety of the food. Several parameters such as peroxide value (PV) and conjugated diene value (CDV) have been used conventionally to monitor the quality of edible oils. In this study, Fourier Transform Infrared (FTIR) spectroscopy was used to evaluate the quality of palm oils after repeated cycles of frying. FTIR spectra were recorded from 4,000 to 400 cm-1, and analysed using multivariate data analysis (MVA) to select important spectral regions and identify clustering pattern among samples. FTIR frequencies at 1,744 and 2,922 cm-1 were found to be the most discriminating variables influencing the separation between fresh and used frying oils. The correlations between peak areas at 1,744 and 2,922 cm-1 with PV...

Microwave heating is one of the most attractive cooking methods for food preparation, commonly employed in households and especially in restaurants for its high speed and convenience. The chemical constituents of oils that degrade during microwave heating do so at rates that vary with heating temperature and time in a similar manner to other type of processing methods. The rate of quality characteristics of the oil depends on the fatty acid composition and the minor components during heating. Addition of oxidative-stable palm olein (PO) to heat sensitive canola oil (CO), may affect the quality characteristics of CO during microwave heating. The aim of this study was to evaluate how heat treatments by microwave oven affect the quality of CO in presence of PO. The blend was prepared in the volume ratio of 40:60 (PO:CO, PC). Microwave heating test was performed for different periods (2, 4, 8, 12, 16 and 20 min) at medium power setting for the samples of CO and PC. The changes in qualit...

The goal of this work was to investigate the impact of the flavoring of some aromatic plants/spices, including rosemary (R), lemon (L) and orange (O) at the concentration of 5% and 35% (w/w) added by 2 methods (conventional maceration and direct flavoring), on quality attributes, chemical changes and oxidative stability of extra virgin olive oil (EVOO). Six flavored oils were obtained (EVOO + O, O + O, EVOO + R, O + R, EVOO + L and O + L). The physicochemical parameters (water content, refractive index, acidity and peroxide value, extinction coefficient, fatty acids, volatile aroma profiles, Rancimat test, phenols and pigments composition) of the flavored oils were investigated. Based on the results obtained, it was observed that flavoring with a conventional process provided increased oxidative stability to the flavored oils, especially with rosemary (19.38 ± 0.26 h), compared to that of unflavored oil. The volatile profiles of the different flavored oils revealed the presence of 3...

In this research, the extraction of polyphenols from Convolvulus arvensis (CA) leaves was optimized using ethanol (80%) at plant/solvent ratios and extraction times which varied between 1/10 to 1/30 (w/v) and 20 to 120 min, respectively. The extract with the highest polyphenol content was obtained at a ratio of 1/30 and 90 min. At 120 ppm, the preceding extract in either lyophilized (LyCAE) or encapsulated (EnCAE) form was evaluated as an antioxidant during the frying process using sunflower oil in comparison to TBHQ. Frying oil quality indices including refractive index, smoke point, acid value, anisidine value, polar and polymer compounds were monitored throughout frying times. FTIR spectroscopy was used to investigate the changes in trans-fatty acids, hydroperoxides and aldehyde contents. The results showed that the phenolic extract, especially in EnCAE form, exhibited superior antioxidant activity over TBHQ, which consequently led to the utilization of this phenolic extract as an antioxidant in frying oils.

The effect of two types of modified atmosphere (MA1: 69% N 2 , 25% CO 2 , 5% O 2 , 1% CO; MA2: 70% N 2 , 30% CO 2 ) on changes in physical and chemical parameters (pH, a w -water activity, TVBN -total volatile basic nitrogen, TMA -trimethylamine, FFA -free fatty acids, PV -peroxide value, TBA -thiobarbituric acid) in muscle tissues of the silver carp was monitored in the study. The samples were stored at temperatures +2 ± 2 o C for 18 days. Changes in gas volumes (CO 2 and O 2 ) in MA s were also monitored. CO 2 levels increased in MA1 but decreased in MA2. At the end of 18 days of storage, a significantly (P < 0.01) lower water activity (a w ) levels were found in samples packaged under MA1, in contrast to samples packaged under MA2 where water activity values showed considerable fluctuation. Variations in pH values in the two types of MA showed similar trends. Sample pH gradually decreased until day 9 of storage. On day 11, muscle tissue pH increased markedly and then began to decrease again. The overall decrease in pH values was more profound in samples packaged under MA1. TVBN and TMA levels in samples packaged under the two types of MA s remained almost identical until day 9 of the experiment. Later, however, significantly (P < 0.01) higher levels of both parameters were found in muscle tissues packaged under MA1. FFA concentrations in silver carp samples in MA1 were significantly lower (P < 0.01) throughout the experiment. The PV increased significantly in both muscle samples tested. Greater fluctuations in this parameter's values throughout the experiment were observed in samples packaged under MA2. Faster rates of oxidation (P < 0.01) were found in samples packaged under MA1 starting on day 9. Maximum TBA values in MA1 and MA2 were observed on days 14 and 18 of the experiment, respectively. From the course of proteolytic and oxidative changes point of view, the more appropriate combination of gases for silver carp storage seems to be the mixture of 70% N 2 and 30% CO 2 (MA2), which allows for muscle storage of up to 9 days. We recommend TVBN as a suitable indicator of freshness, and TBA assay as a suitable indicator of the extent of oxidative processes.

In this study, Ethiopian castor seeds were collected from a local market and studied for their oil yield and physicochemical characteristics including fatty acid composition. Their oil was extracted using mechanical method and using hexane, ethyl acetate, and methanol solvents and its physicochemical properties were studied. It was done by varying solid-to-solvent ratio (1:9, 1:12 and 1:15) and time (1, 3, 5, 6, and 7 h) for the different solvents used for the extraction. A maximum yield of 72.3% for methanol, 68% for ethyl acetate and 61.6% for hexane was obtained at optimum conditions of 1:12 ratio and 7 h extraction. Specific gravity, viscosity, moisture content, refractive index, acid value, saponification value, iodine value, and peroxide value were measured for the different types of oils. Gas chromatography-mass spectrometry analysis of the four types of oils showed that polar solvents give slightly higher ricinoleic acid content than hexane-extracted oil. Hence, use of polar solvents gave the highest yield, good quality, and purer fatty acid composition for the oil prepared from Ethiopian castor seed, making it suitable for industrial applications due to ease of modification of the chemical structure of the oil.

The oxidative stability of mixtures of edible oils containing polyunsaturated fatty acids (PUFA) and microcrystalline cellulose (MCC) was investigated. The mixtures studied consisted of oils of either camelina (CAM), cod liver (CLO), or salmon (SO) mixed with either colloidal or powdered MCC. A 50:50 (w/w) ratio of oil:MCC resulted in an applicable mixture containing high levels of PUFA edible oil and dietary fiber. The oxidative stability of the formulated mixtures and the pure oils was investigated over a period of 28 days. The peroxide value (PV) was assessed as a parameter for primary oxidation products and dynamic headspace gas chromatography mass spectrometry (GC/MS) was used to analyze secondary volatile organic compounds (VOC). CAM and the respective mixtures were oxidatively stable at both 4 and 22 °C during the storage period. The marine oils and the respective mixtures were stable at 4 °C. At 22 °C, an increase in hydroperoxides was found, but no increase in VOC was detec...