Quality Characteristics Of Oil Research Articles

Benchmarking different brands of silicone oils.

To compare the analytical quality characteristics of currently available CE-marked silicone oils used as ocular endotamponades in vitreoretinal surgery. Thirty-four samples of 12 brands were analysed. To assess the quality characteristics of silicone oils, we measured the oligosiloxane content and polydispersity, widely accepted as purity parameters. UV-active substances (> 220nm) were analysed to draw conclusions about the integrity of primary packaging components. We identified significant differences in the impurity profiles of the products tested, which revealed oligosiloxane contents ranging from < 0.1 to 491ppm, polydispersity ranging from 1.6 to 3.0 and UV-active substances (> 220nm) ranging from 0.2 to 3.8AU. The quality characteristics of the analysed silicone oils vary significantly not only among different brands but also among batches of the same manufacturer. Manufacturers should communicate the purity and quality characteristics of their products in an understandable and clear manner. This involves providing a complete certificate of analysis with special focus on quality characteristics, to enable the vitreoretinal surgeon to differentiate between the effects of the silicone oil itself and those of impurities.

Non-destructive discrimination of sesame oils via hyperspectral image analysis

Sesame oil is produced from cheap imported raw materials, but its quality differs depending on the imported form. The purpose of this study was to determine the quality characteristics of sesame oil through hyperspectral image (HSI) analysis. The following types of sesame oil samples were used in this study: sesame oil WS (WS1, WS2) prepared using imported whole-sesame seeds, sesame oil SP (SP1, SP2) prepared using only imported sesame powder and sesame oil WSP (WSP1, WSP2) prepared by mixing imported sesame powder with whole-sesame seeds. The principal component analysis revealed that WS and SP or WS and WSP had different principal components. As a result of partial least squares-discriminant analysis, WS and WSP had an average R2 of 0.9289 in a training model, and prediction R2 was the highest at 0.8333 in a test model. The developed model was affected by C-H stretch second overtones for fatty acids and C-H and O-H bonds corresponding to phenolic absorbance. The average R2 of partial least squares regression developed owing to fatty acid and phenolic compound content was the highest. Therefore, it was possible to analyze the quality characteristics of sesame oil according to the form of raw material using hyperspectral image.

Temperature Dependence of Oxidation Kinetics of Extra Virgin Olive Oil (EVOO) and Shelf-Life Prediction.

Producers have to guarantee the extra virgin olive oil (EVOO) quality characteristics reported in the Regulation (CEE) 2568/91 throughout the product shelf-life (SL). Unfortunately, due to the development of oxidative reactions, some quality indices change during storage leading to a progressive deterioration of EVOO quality. To avoid the risk of product downgrading in the virgin oil category, the development of effective shelf-life prediction models is extremely important for the olive oil industry. In this research, the accelerated shelf-life testing (ASLT) protocol was applied to evaluate the temperature dependence of selected oxidation indexes as well as to develop a shelf-life predictive model. The evolution of conventional (peroxide value, K232, K270, polyphenols, tocopherols and hexanal) and unconventional parameters (conjugated trienes and pyropheophytin a) was monitored in bottled EVOO stored in the dark at increasing temperature (25, 40, 50 and 60 °C). Accordingly, for well-packed products with reduced oxygen in headspace, the best shelf-life index allowing the ability to predict EVOO SL turned out to be K270. In addition, pyropheophytin a (%) has been shown to be more sensitive to temperature changes than the secondary oxidation indices, thus suggesting its use as a freshness indicator for storage temperatures higher than 25 °C.

Effect of freeze-thaw pretreatment on yield and quality of perilla seed oil

This work investigated the effect of freeze-thaw (FT) pretreatment on the yield and quality of oil cold-pressed from perilla seeds. FT pretreatment ruptured the perilla seed coat and internal structure, resulting in an oil yield of 78.71%, about 2.5-times greater than the yield from untreated control perilla seeds. Acid values were relatively low (0.54 mg KOH/g) and not different in the FT-treated and control oil. Likewise, peroxide values were low (1.34 meq/kg) and not different amongst the treatment groups. Viscosity values (96.5 mPa s) were indicative of a light oil while color values (L*a*b*) indicated a light yellow-green color. The major unsaturated fatty acids were identified as linolenic acid (C18:3, ω−3), linoleic acid (C18:2, ω−6), and oleic acid (C18:1, ω−9). The most abundant volatiles were 1-(furan-2-yl)-4-methylpentan-1-one and 3-(4-methyl-3-pentenyl)-furan in both of the oil samples. However, the normalized relative intensity of the volatile compounds was reduced in the FT-treated PO. The acylglycerol profile in FT-treated and control PO was not different, yet another indication that FT pretreatment did not increase oil rancidity or oxidative instability. FT pretreatment on oil seeds before cold-pressing is an attractive technique for obtaining high oil yield without deteriorative effects on the quality characteristics of edible oil.

Evolution of Phenotypic Traits and Main Functional Components in the Fruit of 'Chenggu-32' Olives (Olea europaea L.) Cultivated in Longnan (China).

China has taken olive cultivation as a significant part of its agricultural development. Longnan city of Gansu province was marked into the world olive distribution map by International Olive Oil Council in 1998. However, so far, little research has been done on the growth and development stages of Chinese olives. The objective of this study was to investigate the dynamics changes of several quality characteristics of olive oil at different sampling times. Olive fruit of 'Chenggu-32' grown in Longnan were harvested at twenty-four time periods and used for determination of phenotypic traits and oil quality characteristics: total polyphenols and flavonoids contents, as well as fatty acid composition by using Gas Chromatography-Mass Spectrometer (GC-MS) and analysed by using Principal Components Analysis (PCA). Towards maturation, fruit moisture content decreased while oil content increased. Levels of both total flavonoids and total polyphenols contents slightly decreased first then increased. The ratio of unsaturated to saturated fatty acids was close to three. The ratio of monounsaturated fatty acids (MUFA)/ polyunsaturated fatty acids (PUFA) was from 2.28 to 4.05. The oleic acid (C18:1)/linoleic acid (C18:2) ratio was varied between 5.23 and 10.67 according to different sampling dates. The olive oil had lower oleic acid (C18:1) levels, higher linoleic acid (C18:2), linolenic acid (C18:3), and palmitic acid (C16:0) levels compared to Codex values (2017) in some periods, which is the characteristics fatty acid composition of 'Chenggu-32' variety in Longnan, China.

Some investigations on surface quality indicators for OHNS die steel machined with suspended powder EDM process

The study focuses on the evaluation of surface quality characteristics of oil hardened non shrinking die steel surface machined with suspended powder electrical discharge machining process. Pure copper metal is used as an electrode material, and tungsten powder is used as suspended medium for the purpose. Machining experiments were carried out by varying one parameter at a time. After each test, the machined surface is analysed for evaluating its surface roughness and microhardness values. It is found that combination of 4 A gap current, 12 μs pulse on span and 7 μs pulse off span will result in optimum surface quality indicators for the SPEDM process. Also, dry sliding wear experiments were carried out on the machined surface to evaluate the frictional force and coefficient of friction. Spectroscopic analysis and energy dispersive X-ray diffraction analysis on the machined surface indicate a considerable rise in carbon and tungsten content on the recast white layer of the machined surface. Scanning electron microscopic analysis of the machined surface revealed the presence of compounds of tungsten on the recast white layer. Also, micro-cracks were observed on the machined surface which is due to higher gap current setting during EDM process.

Some investigations on surface quality indicators for OHNS die steel machined with suspended powder EDM process

The study focuses on the evaluation of surface quality characteristics of oil hardened non shrinking die steel surface machined with suspended powder electrical discharge machining process. Pure copper metal is used as an electrode material, and tungsten powder is used as suspended medium for the purpose. Machining experiments were carried out by varying one parameter at a time. After each test, the machined surface is analysed for evaluating its surface roughness and microhardness values. It is found that combination of 4 A gap current, 12 μs pulse on span and 7 μs pulse off span will result in optimum surface quality indicators for the SPEDM process. Also, dry sliding wear experiments were carried out on the machined surface to evaluate the frictional force and coefficient of friction. Spectroscopic analysis and energy dispersive X-ray diffraction analysis on the machined surface indicate a considerable rise in carbon and tungsten content on the recast white layer of the machined surface. Scanning electron microscopic analysis of the machined surface revealed the presence of compounds of tungsten on the recast white layer. Also, micro-cracks were observed on the machined surface which is due to higher gap current setting during EDM process.

Olive tree (Olea europaea L. cv. Zelmati) grown in hot desert climate: Physio-biochemical responses and olive oil quality

Several studies have highlighted the particular vulnerability of the Mediterranean region regarding climate change. In Tunisia, predictions indicate a temperature increase of 2.7 °C on the horizon of 2050, which may contribute to the degradation of agro-ecosystems and particularly the olive sector. The question that arise: how will the “Zelmati” olive tree behaves in the case of global warming as it is predicted for the south of the country? Therefore, olive trees (Olea europaea L. cv. Zelmati) were cultivated in Kebili-Rjim Maatoug region, which is a desert oasis in southwestern Tunisia characterized by a hot desert climate. The physio-biochemical responses of olive trees as well as olive oil quality characteristics were determined in comparison to those of plants cultivated in the classic region of Sfax-Taoues characterized by an arid climate. Kebili-Rjim Maatoug region exhibited high temperature and insolation, low air humidity and rainfall than Sfax-Taoues region during the different phenological stages of the olive trees. The hot desert climate resulted in a decrease of chlorophyll content, associated with an increase of malondialdehyde, soluble proteins, proline and soluble sugars contents in leaf tissues. Furthermore, polyphenols and carotenoids contents significantly increased (p < 0.05) in olive oil from olive trees grown in Kebili-Rjim Maatoug region. Nevertheless, the oleic acid content decreased below 50%, the palmitic acid exceeded 20% and the linolenic acid exceeded 1%, which was not in accordance with the commercial standards of olive oils.

Acoustic Control Method of Quality Characteristics of New Transformer Oil

Power transformers are the most expensive and strategically important components of any power generation and transmission system. Diagnostics methods result from the necessity to provide the operational reliability of power equipment and extend its operation time. Acoustic method is one of the perspective methods to determine transformer oil quality. In comparison with standard methods the acoustic method have follow important advantages: low labor intensity, need lack of the difficult expensive equipment, carrying out researches in vitro frames and high qualification of researches. This study represents results of impurity influence investigation (water and cellulose) on an acoustic range of new transformer oil

Effect of bag-in-box packaging material on quality characteristics of extra virgin olive oil stored under household and abuse temperature conditions

• Shelf life of EVOO packaged in tin-plated steel containers at 22 °C was 80 days. • Shelf life of EVOO packaged in tin-plated steel containers at 37 °C was 60 days. • Shelf life of EVOO packaged in bag-in-box containers at 22 °C was 120 days. • Shelf life of EVOO packaged in bag-in-box containers at 37 °C was 100 days. • Bag-in-box retains EVOO quality longer than tin-plated steel. The effect of bag-in-box (B) packaging material on quality characteristics of extra virgin olive oil (EVOO) was studied as a function of storage time (0–120 days) and temperature (22 °C and 37 °C). Olive oil packaged in tin-plated steel (S) containers served as control. Olive oil sampling was carried out every 20 days, assessing quality deterioration by monitoring multiple quality parameters: acidity, PV, K 232 , K 270 , ΔK, color, total phenolic content (TPC), FA composition and volatile compounds’ profile. Based mainly on acidity, PV, K 232 , and K 270 values, samples packaged in S could no longer rank as EVOO after 80 days of storage at 22 °C, and after 60 days at 37 °C. Samples stored in B retained EVOO specifications throughout storage at 22 °C and had a 100 days shelf life at 37 °C. Conclusively, results showed that B packaging proved to be more suitable for all olive oil samples even for those exposed to abuse temperatures.

Oil Quality and By-product Yield Characteristics Based on Pre-treatment of Waste Plastics in Pyrolysis Process

Oil Quality and By-product Yield Characteristics Based on Pre-treatment of Waste Plastics in Pyrolysis Process

Impact of infrared and dry air roasting on the oxidative stability, fatty acid composition, Maillard reaction products and other chemical properties of black cumin (Nigella sativa L.) seed oil

Black cumin seed (BCS) is a novel oil source with potential health benefits. This study investigates the influence of infrared (IR) and dry air (DA) roasting (140, 160 and 180 °C for 5 and 10 min) on BCS oil quality characteristics. Results revealed that the oxidative stability index (OSI), Maillard reaction products (MRPs), chlorophyll and carotenoid contents were increased while acid value (AV), peroxide value (PV) and color values were decreased in DA roasted (180°C for 10 min) BCS oil compared to other DA and IR treatments. DA and IR roasting slightly influenced the fatty acid composition (FAC) of BCS oils. FTIR spectra showed minor changes in peak intensities (at 2854, 2929 and 3008 cm−1) of DA and IR roasted BCS oils. DA roasting proved more effective than IR roasting. The oil from the DA roasted BCS at 180°C for 10 min had significantly higher oil quality and oxidative stability.

Analysis quality characteristics of virgin coconut oil (VCO): comparisons with cooking coconut oil (CCO)

This study aims to examine the quality of cooking coconut oil (CCO) and virgin coconut oil (VCO). The analysis was carried out as a physical parameter test including organoleptic and density while the chemical parameter test was: free fatty acid (FFA) peroxide number and test of saponification number. The sample oil used comes from coconut oil made traditionally by virgin coconut oil or commonly abbreviated as VCO, which is coconut oil which passes through a different extraction process with ordinary coconut oil so it is believed to have higher quality and provide more benefits. Samples derived from coconut oil traditionally processed in Beji Village, Boyolangu District with the brand "MALIKA". It was found that both oils had relatively the same physical parameters, the difference in density on VCO and CCO: 0.88 g / ml and 0.82 g / ml. As for the chemical parameters of free fatty acids, peroxide numbers, and saponification numbers of the VCO and CCO comparisons: 0.165: 0.207; 0.54: 0.68; 203: 321, so that the overall VCO has good quality, while CCO has an unfavorable saponification number.

Impact of roasting and extraction methods on chemical properties, oxidative stability and Maillard reaction products of peanut oils.

This study was designed to investigate the influence of dry air roasting (140, 160 and 180°C for 5 and 10min) and extraction methods (solvent and mechanical) on peanut oil quality characteristics. Oil yield, oxidative stability index (OSI), radical scavenging activity (RSA), and Maillard reaction products were increased while peroxide value (PV) and conjugated dienes were decreased in oil of peanuts roasted at 180°C for 10min. Oils extracted mechanically from roasted peanuts had lower PV while higher OSI and RSA than the solvent-extracted oils. The fatty acid composition of oils from roasted peanuts (at 160 and 180°C for 10min) changed slightly compared to unroasted peanuts. The level of 5-hydroxymethylfurfural and non-enzymatic browning index was significantly increased in oil from peanuts roasted at 180°C for 10min. FTIR spectra showed a slight change in peak intensities with no observed peak shift in oils extracted from peanuts roasted at 180°C for 10min. Based on the results obtained, mechanically extracted oil from peanuts roasted at 180°C for 10min improves oil quality characteristics and enhances oxidative stability.

Effect of Enzymatic Aqueous Extraction on Quality Characteristics of Maize Germ Oil During Storage

Enzyme-assisted aqueous extraction (EAAE) method is among the emerging technologies and eco-friendly process for oil extraction. The aim of this study was to evaluate the effect of oil extraction methods and packaging material on shelf life of maize germ oil. Maize germ oil extraction was done by EAAE and solvent extraction method. HDPE and glass bottles were used as packaging materials. Quality characteristics evaluated were acid number, pH value, total phenolics content, colour change, unsaponifiable matter, saponification value, peroxide value and density at 15-day intervals for 90 days of storage period. The quality characteristics of oil changed with the passage of storage periods, and maximum change upto 190 % increase in peroxide value occurred when oil was solvent extracted and stored in HDPE bottle. The quality parameters of EAAE extracted oil were superior to solvent extracted oil. During storage acid number, pH, total phenolics, unsaponifiable matter and peroxide value of oil were significantly affected (P&lt; 0.05) by packaging material, storage period and method of oil extraction.

The Pretreatment of the Seeds Affects the Quality and Physicochemical Characteristics of Watermelon Oil and Its By‐Products

AbstractThe aims of this study were to produce cold‐pressed oils from watermelon seeds, which were previously treated with seed boiling and roasting, and to characterize the oils and press cakes. The watermelon seeds were found as rich sources of protein, oil, and minerals. Seed boiling pretreatment resulted in a higher oil recovery (51.31%) than seed preroasting (44.21%). Seed pretreatments did not cause any difference in the fatty acid (FA), sterol, and tocopherol compositions. Linoleic acid (LNA) was the major FA (54.57 and 54.62%) with higher contents of total unsaturated (74.41 and 75.52%) FA. β‐Sitosterol (202.79 mg/100 g oil and 202.90 mg/100 g oil) and γ‐tocopherol (361.45 mg kg−1 oil and 365.98 mg kg−1 oil) were the major components. The oils started to crystallize at around 1.80 and 1.75°C, and completely crystallized oils melted at around −35.66 and −35.78°C, respectively. Seed boiling pretreatment reduced the quantity of the most phenolic compounds in the oil (51.54 and 22.74 mg kg−1 total phenolics). The oxidative induction times of the oils were 11.91 and 11.49 min. In these cold‐pressed oils, volatile compounds associated with roasted/nutty and vegetable/herbal aroma descriptions were predominantly detected. Sensory descriptive analysis indicated that the oils are poor in terms of different sensory terms. Consumer tests showed that these oils are acceptable for direct consumption. Hence, this raw material could be used to produce edible oils.

Effect of Enzymatic Aqueous Extraction on Quality Characteristics of Maize Germ Oil During Storage

Enzyme-assisted aqueous extraction (EAAE) method is among the emerging technologies and eco-friendly process for oil extraction. The aim of this study was to evaluate the effect of oil extraction methods and packaging material on shelf life of maize germ oil. Maize germ oil extraction was done by EAAE and solvent extraction method. HDPE and glass bottles were used as packaging materials. Quality characteristics evaluated were acid number, pH value, total phenolics content, colour change, unsaponifiable matter, saponification value, peroxide value and density at 15-day intervals for 90 days of storage period. The quality characteristics of oil changed with the passage of storage periods, and maximum change upto 190 % increase in peroxide value occurred when oil was solvent extracted and stored in HDPE bottle. The quality parameters of EAAE extracted oil were superior to solvent extracted oil. During storage acid number, pH, total phenolics, unsaponifiable matter and peroxide value of oil were significantly affected (P&lt; 0.05) by packaging material, storage period and method of oil extraction.

METHOD FOR EXPERIMENTAL DETERMINATION OF THE LIQUID DIELECTRIC RESOURCE AND MEASURES FOR ITS RESTORATION

The theoretical foundations of changes in the transformer oil quality characteristics, depending on the aging degree, are presented. The introduction of a new indicator of the exploitational transformer oils quality – “stability against oxidation” – is substantiated as a way of solving the scientific and technical problem of assessing the resource characteristics of a transformer insulating system. In order to select the best measures to maintain the quality of power transformers insulating oils, a newly developed “Method for the Experimental Determination of the Luquid Dielectric Resource and Measures for its Restoration” is presented.

시중 유통 생 들기름의 저장기간별 품질특성

시중 유통 생 들기름의 저장기간별 품질특성

Chemical and Sensorial Characteristics of Olive Oil Produced from the Lebanese Olive Variety ‘Baladi’

The olive oil quality, nutritional and sensorial characteristics are associated with the chemical composition, which is the result of a complex interaction between several environmental, agronomical and technological factors. The aim of the present study is to investigate the impact of the geographical origin, harvesting time and processing system on the chemical composition and sensorial characteristics of olive oils produced from the Lebanese olive ‘Baladi’. Samples (n = 108) were collected from North and South Lebanon, at three different harvesting times and from four processing systems. Results showed a strong effect of origin, processing system and harvest time on oil quality, fatty acid composition, total phenols and OSI. The early harvest showed higher total phenols content (220.02 mg GAE/Kg) and higher OSI (9.19 h). Moreover, samples obtained from sinolea and 3-phases recorded the lowest free acidity (0.36% and 0.64%), and the highest OSI (9.87 and 9.84 h). Consumers were not unanimous regarding the studied factors, although samples recording high ranks were mostly from South using sinolea, 3-phases and press systems at early and intermediate harvest. The overall findings suggest that the selection of the harvesting time and of the processing system could have significant influence on the characteristics of the olive oil.