Low trans hydrogenation of edible oils

Hydrogenation of edible oils is an important process in the food industry to produce fats and oils with desirable melting properties and an improved shelf life. However, beside the desired hydrogenation reaction trans fatty acids are formed as well. As several studies indicate a negative health effect of trans fatty acids, consumer demands will urge the food producers to lower the content of trans fatty acids in their products. This article describes the option to reduce the trans levels in the hydrogenation of an edible oil by changing process conditions and by applying alternative low trans heterogeneous catalysts.     

Modeling the degradation of natural rubber male condoms

Most condom manufacturers claim a 5 year shelf‐life for their products; however, condoms can decay much more rapidly than the reported shelf‐life would suggest, because of the uncontrolled storage conditions. For this reason, development of mathematical model to predict condom shelf‐life as a function of storage conditions can be very useful. In this work, six brands of condoms were aged under subtropical ambient conditions for 5 years and under accelerated conditions at four temperatures for various times. The changes in burst pressure and burst volume were used as the main indicators of product degradation. Experimental data were analyzed and two mathematical models (both based on the reparameterized Arrhenius equation) were proposed to describe the obtained data. It is shown for the first time that it is possible to estimate and predict the degradation of natural rubber condoms with confidence with the help of the proposed models, based on data obtained from accelerated degradation experiments, provided that different activation energies are used for the burst pressure and volume. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of filtration on virgin olive oil stability during storage

The effect of filtration and dehydration on the stability and quality of virgin olive oil during storage at room temperature (25 °C) and under accelerated conditions (40 °C) was studied. Different types of monovarietal olive oil, namely unfiltered (UF), filtered (F) and filtered‐dehydrated (FD), were obtained from Arbequina, Colombaia, Cornicabra, Picual and Taggiasca cultivars. Results showed that filtration and dehydration decreased the rate of hydrolysis of the triacylglycerol matrix, especially at the higher temperature and in oils with a higher initial free acidity (e.g. free acidity of 0.82% and 0.63% in UF and FD Colombaia samples, respectively, after 8 months of storage), and delayed the appearance of rancid defects (e.g. UF and FD Arbequina samples lost extra‐virgin grade after 10 and 12 months of storage, respectively). The formation of simple phenols due to the hydrolysis rate of their secoiridoid derivatives was also greater in unfiltered olive oils (e.g. 174 μmol/kg and 137 μmol/kg in UF and FD Picual samples, respectively, after 8 months of storage). Thus, filtration and especially dehydration could help to prolong the shelf life of high‐quality and less stable olive oils like those obtained from the Arbequina and Colombaia varieties.     

Analysis of Reaction Kinetics of Edible Oil Oxidation at Ambient Temperature by FTIR Spectroscopy

Edible oils are studied to analyze their reaction kinetics during oxidation and predict shelf life at ambient temperature. Rapeseed oil (RO), soybean oil (SO), linseed oil (LO), and peanut oil (PO) are detected via Fourier transform infrared spectroscopy with a mesh cell as spectral acquisition accessory. The reaction kinetics of ROOH bonds, C═O bonds, trans double bonds (TDBs), and carbon chain skeletons (CCSs) are determined by absorbance changes in their characteristic absorption peaks. Prediction models for shelf life based on various characteristic absorption peaks are converted via the reaction kinetics equations of the oils. Results show that first‐order reaction kinetics are used to describe absorbance changes of ROOH bonds in PO, SO, and LO, while zero‐order reaction kinetics are used to describe the absorbance changes in RO. Both C═O bonds and CCS absorbance changes in the four oils satisfy first‐order reaction kinetics. TDBs absorbance changes in PO, SO, and LO are in accordance with zero‐order reaction kinetics. The regression equations of reaction kinetics exhibit good fitting degree (coefficient of determination, R² > 0.9000) and statistical significance (p < 0.001), indicating that the proposed method can be used to analyze the reaction kinetics of oil oxidation and predict shelf life. Practical Applications: The reaction kinetics of RO, SO, LO, and PO are studied at ambient temperature and the shelf life is predicted by using FTIR spectroscopy based on the absorbance changes of ROOH bonds, C═O bonds, TDB bonds, and CCS in the oils. The shelf life of edible oils can be more effectively predicted in this case and provide a practical reference for food industries. Furthermore, the proposed technique is rapid, green, and accurate, and allows real‐time characterization of absorbance changes in various characteristic absorption peaks, which corresponded to different oxidation products. By this method, it is possible to reflect real‐time information for different quality indices (such as peroxides and acid values) of oil oxidation simultaneously, and unnecessary to measure these indices directly one by one, saving manpower and material resources. Therefore, FTIR spectroscopy is convenient for the rapid evaluation of oxidation stability and shelf life of edible oils under ambient temperature.     

Acetin fats. I. Products made from mixed acetin fats

Summary The most striking effect of the introduction of the acetyl group into the glyceride molecule is the reduction in melting point. This effect permits the preparation of low melting fats and oils, or acetin fats, of a high degree of saturation and of a significantly increased oxidative keeping quality. Mixed acetin fats containing monoacetyl (monoacetins), diacetyl (diacetins), and normal triglycerides were made by random interesterification of normal fats or oils with triacetin, followed by removal of the residual triacetin. In general, mixed acetin fats may replace normal triglycerides in any edible fat use. Edible fat products including shortenings, margarines, or spreads, salad oils, and frying oils were made from acetin fats and oils. Suggested inedible use applications of the acetin fats and oils include plasticizers, tinning oils, and hydraulic oils.     

Fats and oils as chemical intermediates: Present and future uses

Currently, fats and oils possess about 40% of the paint binder, 50% of the surfactant, and 15% of the plasticizer markets. Other markets considered here, with estimated fats and oils percent share of these markets in parentheses, are: adhesives (1%), Agrichemicals (10%), engineering thermoplastics (2%) and synthetic lubricants (20%). With the expected growth for these markets and with fats and oils retaining the same percent share, an additional 3000 million pounds of fats and oils would be needed in 1990. In the likely event that the fats and oils share is accelerated, an additional 7500 million pounds would be required. These requirements could be met by an additional 10 or 25 million acres of soybean production, respectively, which can be easily attained by U.S. agriculture or by diversion of other crops or animal fats from edible use or export.     

Oxidative stability of black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.) and niger (Guizotia abyssinica Cass.) crude seed oils upon stripping

Information on stability of edible oils is important for predicting the quality deterioration of the oil during storage and marketing. Stripping of crude oils removes most of non‐triacylglycerol components, including polar lipids and phenolics. Oxidative stability of black cumin (Nigella sativa L.), coriander (Coriandrum sativum L.) and niger (Guizotia abyssinica Cass.) crude and stripped seed oils was investigated and compared. The factors influencing the oxidative stability of different seed oils were also discussed. Oil samples were stored under accelerated oxidation conditions for 21 d. The progress of oxidation at 60 °C was followed by recording the ultraviolet absorptivity and measuring the formation of oxidative products (peroxide and p‐anisidine values). Inverse relationships were noted between peroxide values and oxidative stabilities and also between secondary oxidation products, measured by p‐anisidine value and stabilities at termination of the storage. Absorptivity at 232 nm and 270 nm increased gradually with the increase in time, due to the formation of conjugated dienes and polyenes. In general, oxidative stabilities of crude oils were stronger than their stripped counterparts and the order of oxidative stability was as follows: coriander > black cumin > niger seed. Levels of polar lipids in crude oils correlated with oxidative stability. Thus, the major factor that may contribute to the better oxidative stability of crude oils was the carry‐over of their polar lipids.     

Assessment of thin-film oxidation with ultraviolet irradiation for predicting the oxidative stability of edible oils

The oxidative stability of edible oils and samples of rapeseed oil with added antioxidants, metal ions, phospholipids and oxidized oil was assessed by a method involving oxidation of a thin film of oil with ultraviolet (UV) irradiation at 100°C. Induction times determined by this method were compared with those determined with the Rancimat at 100°C. The two methods agreed well in describing the effects of additives on the stability of the edible oil. Induction times were considerably shorter for the thin-film UV method, and the method may have potential as an accelerated test method for assessing the effect of additives on the oxidative stability of relatively stable oils and fats. The correlation between the Rancimat and the thin-film UV induction times also was assessed at 80°C for rapeseed oil containing additives, but there was no advantage in using the lower temperature alone because the induction times were 2–7 times longer than at 100°C. However, use of two elevated temperatures is likely to improve predictions of stability at lower temperatures, especially for samples containing copper, which have an exceptionally high-temperature coefficient. The thin-film UV method showed a poorer agreement with the Rancimat for comparing the oxidative stability of some fats and oils. For instance, corn oil was more stable than soybean oil in the Rancimat test but the order of stability was reversed in the thin-film UV test. Cocoa butter was much more stable in the Rancimat test than when assessed by the thin-film UV test.     

Lipidomic analysis of fats and oils – a lot more than just omega‐3

Edible oils and fats are among the most abundant cooking ingredients in the world, and are an important part of a healthy balanced diet, especially if they are high in omega‐6 and omega‐3 polyunsaturated fatty acids. Rather than just the total fatty acid compositions, the analysis of individual lipid species within these oils and fats has become increasingly important. Within the past decade several mass spectrometric lipidomics methods have been adapted and applied to the analysis of edible oils and fats. These methodologies are vital for the analysis of a plethora of lipid species that will be important for numerous health and sustainability issues in the future.     

Stability of a phenol‐enriched olive oil during storage

The use of an emulsifier to stabilize the phenolic compounds added in the preparation of an enriched olive oil was evaluated. Two emulsifiers, lecithin and monoglyceride, were studied. The results showed lecithin to be the most convenient, due to the increase in the value of the oxidative stability of the phenol‐enriched oils in relation to the enrichments prepared with monoglycerides. After that, the shelf life of the prepared oils was evaluated during a period of 256 days of storage at 25°C in the dark. Oil quality parameters, total phenolic content, bitterness index and oxidative stability were studied during the storage period. Additionally, the phenolic composition and antioxidant capacity (by using the ORAC assay) were evaluated at the end of the storage. The phenolic enrichment of the oils allowed the shelf life of the oils to be extended compared with the control (virgin olive oil without phenol addition), delaying the appearance of peroxides and improving their oxidative stability. In addition, the higher content of phenolic compounds in the oils at all stages of storage is desirable in order to increase the intake of these beneficial compounds. Practical applications : The preparation of phenol‐enriched olive oils with a higher phenolic content than the commercial virgin olive oils is of special interest to increase the ingestion of these healthy compounds the daily intake of which is limited due to the high caloric value of olive oil. There are two key points in the development of this product: (i) the dispersion and stabilization of the phenol extract in the oil matrix and (ii) the stability of the phenols in the prepared oils to guarantee the phenol concentration during their shelf life. It is important to study the use of emulsifiers to determine if they allow an improvement in the dispersion of the phenolic extract, and their stabilization in the final product. In addition, the emulsifiers could mask the bitter taste of the enriched oils, which is desirable to increase consumer acceptance of the enriched oil.     

Principles of palm olein fractionation: a bit of science behind the technology

Dry fractionation is a well‐established and versatile fat modification technology that can produce a broad spectrum of edible oils and fats. Due to its specific chemical composition, especially palm oil can be processed by this technology into fractions that serve as salad oils, frying oils, margarine fats. Whereas the first step of this multi‐stage production process is well understood, the edible oil industry all over the world is much more often confronted with problems in the second stage of the process, when the liquid palm olein is further fractionated. The process of palm olein crystallization is indeed a lot more difficult to control. This article therefore elaborately explains the main, fundamental causes for this sensitivity of palm olein during the fractional crystallization. It further discusses which and how components present in refined palm olein can be responsible for process instability and how they affect the quality of the end products on an industrial scale. The article also highlights which novelties and innovation in dry fractionation technology are currently under investigation.     

A comparison of several analytical techniques for prediction of relative stability of fats and oils to oxidation

Three analytical methods proposed by various workers for predicting the relative stability of fats and oils to oxidation have been compared on a series of samples. The Eckey Oxygen Absorption, the modification of the A.S.T.M. Oxygen Bomb (4), and the Active Oxygen Method (AOM) were applied to combinations of animal and vegetable fats and oils, with and without added monoglycerides and antioxidants. The results indicate that the Eckey Oxygen Absorption and modified ASTM Oxygen Bomb methods are more precise than the AOM method, and more in keeping with the experience in the fat and oil field in relation to actual performance stability than the AOM. Experimental relationships of these factors and methods to shelf life storage studies measured organoleptically will be the subject of a later paper.     

Oils and fats,the historical cosmetics

Many of the uses of oils and fats in cosmetics are the same as those of antiquity. However, technical progress has taken these natural materials apart and put them together differently. So now cosmetic chemists have the advantages of both natural and man-made fats and oils. Furthermore, today there are available a variety of antioxidants which extend the shelf life of cosmetics made with them.     

Stabilizer Depletion in Single Base Propellant from Unexploded Ordnance

Decomposition of nitrocellulose‐based propellant is a well‐known problem that results in insufficient shelf‐life of the ammunition if the propellant is not stabilized with appropriate materials. To investigate the influence of storage conditions on the shelf life of old propellant powder HPLC analytics according to AOP‐48 were carried out to determine the stabilizer consumption at different temperatures. The ingredients of the propellant were also analyzed. The results show that the examined propellant samples from WW II production are still containing stabilizer. Humidity in combination with elevated temperature seems to be the most influencing parameter for decomposition of this type. The analyzed propellants seem to be stable even after about 70 years under bad storage conditions. You might draw conclusions from these results for modern time propellant powders, which are stored under controlled conditions.     

Sodium azide and metal chelator effects on 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging compounds from methylene blue photosensitized lard

Thermal oxidation of edible oils can generate 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging compounds from oxidized lipids (RSOLs). However, effects of photosensitization on the formation of RSOLs have not been reported yet. Methylene blue (MB) photosensitization and involvement of singlet oxygen and transition metals on the RSOL formations were determined in stripped lard oils. RSOLs were formed in lard containing MB and visible light irradiation only. Addition of sodium azide decreased RSOLs with concentration dependent manner, which implies singlet oxygen was involved on the RSOL formation. Ethylenediammetetraacetic acid (EDTA), a well known metal chelator, accelerated the formation of RSOLs through protecting the decomposition of MB photosensitizer. Results from p‐anisidine values showed that RSOLs from photosensitization may not be formed from the same pathways compared to thermal oxidation. Practical application: Understanding mechanisms of lipid oxidation can help extend the shelf‐life of foods. Photosensitization plays important roles in accelerating the rates of lipid oxidation. The results of this study showed that foods containing photosensitizers can generate radical scavenging compounds from oxidized lipids (RSOLs) under visible light irradiation and singlet oxygen is involved in the formations of these compounds. However, these compounds may not share the same pathways with thermally oxidized lipids. Metal chelating agents accelerated the rates of lipid oxidation and formation of RSOLs which implies that metal chelators can act as prooxidant. Careful considerations are necessary on the addition of metal chelators because non‐polar photosensitizers can act a prooxidant.     

Sal olein and mahua olein for direct edible use

Vegetable butter oleins are obtained as by-products during the fractionation process employed for making cocoa butter substitutes from sal and mahua. Outlets for these olein portions would not only ensure total utilization of these nontraditional oils, but would also provide an extension of edible oil supplies. The normal analytical characteristics and fatty acid compositions of the olein portions obtained from sal and mahua fats were investigated under appropriate conditions of time and temperature. Sal olein was found to be rich in stearic (33.5–34.0%) and oleic acids (49.1–50.0), whereas mahua olein contained palmitic (18%), stearic (21%) and oleic (38%) acids. Projections from Schaal oven stability studies indicated that even without an antioxidant addition, the oleins could be stored for 4–5 months, and with 0.01% tertiary butyl hydroquinone, the storage life could be prolonged to over one year. Deep-fat frying experiments indicated that the oleins showed a slow buildup rate of total polar material and are quite suitable for such use.     

Shelf‐life prediction of perilla oil by considering the induction period of lipid oxidation

Kinetic models for the induction period (IP) of lipid oxidation were developed to predict the shelf‐life of perilla oil during storage. The degree of lipid oxidation was measured in terms of peroxide values (PV). The perilla oil was stored in the dark at various temperatures. The IP was measured at the intersection point of two linear lines and in terms of time and PV at the IP. The IP was expressed by an Arrhenius‐like relationship. Before and after the IP, the reaction followed pseudo‐zero‐order kinetics. The oxidation degrees according to storage times were computed by considering the variables, IP and reaction rate constants. The prediction model equation that was developed to determine shelf‐life is more accurate than in previous studies. Conclusively, considering the IP of lipid oxidation is essential for predicting the shelf‐life of perilla oil and is expected to be applicable to other vegetable oils. Practical applications : In kinetic modeling for shelf‐life estimation in terms of lipid oxidation, induction period (IP) is rarely considered. Thus the estimation of peroxide values (PV) from such models might be inaccurate. The IP was observed in perilla oil oxidation and kinetic models involving the IP were developed. This work enables a better estimation of oxidation. Besides, a shelf‐life diagram of perilla oil has been constructed as a valuable tool for quality control in the food industry.     

Accelerated Shelf Life Testing (ASLT) of Oils by Light and Temperature Exploitation

The peroxide formation rate was measured in sunflower and soybean oils exposed to increasing light intensity, from 0 to 8000 lx, at 10, 20 and 30 °C. Results indicated that shelf life estimation of photosensitive foods under actual or accelerated conditions cannot be correctly achieved if the effect of light is not taken into account. At each lighting level, the Arrhenius equation was applied to develop a model predicting oil shelf life. Thermal activation energy was lower than 50 kJ/mol, indicating temperature to be a scarcely efficient accelerating factor. In contrast, the oxidation rate was significantly affected by light according to a power law equation, whose parameters describe the electromagnetic activation energy of the reaction. The model accounting for the effect of light on oxidation rate was merged with the Arrhenius equation to get a model predicting shelf life on the basis of the concomitant changes in both temperature and light.     

Rapid and direct quantitative analysis of positional fatty acids in triacylglycerols using 13C NMR

There is increasing evidence that the positional fatty acid composition (FAC) of TAG is more important than total FAC with regard to nutrition values of edible oils and fats. A rapid and direct regiospecific analysis of positional fatty acids in TAG using ¹³C NMR was developed to overcome the tedious conventional methods which involve enzymatic hydrolysis, Grignard chemical degradation, and chromatography analysis. A set of NMR data acquisition parameters and processing methods had proven their excellent versatility and applicability on various types of oils and fats, with systematic error of 1.0 mol%. It was found that there are discrepancies between the regiospecific analysis results obtained by the current method and by conventional methods. Probable acyl migration occurring in the hydrolysis process in conventional methods is a noted problem. As the current ¹³C NMR method is a direct measurement and no hydrolysis of the sample is needed, acyl migration during the analysis is eliminated. As a result, the saturation level is always higher at sn‐1, 3 positions and lower at sn‐2 position in TAG structure of oils in the regiospecific data obtained from the current ¹³C NMR than that from conventional methods. In the absence of laborious chemical derivatization, this method is simple, accurate, and user‐friendly for researchers, especially for nutritionists to support their nutritional studies from the perspective of positional FAC of edible oils and fats.     

废弃食用油脂运用活性凹凸棒土脱色的试验研究

因为废弃食用油脂直接采用超临界法制备生物柴油的外观品质很差,所以本文选用活性凹凸棒土对废弃食用油脂进行预处理脱色研究,对影响废弃食用油脂脱色率的因素进行了讨论。得出活性凹凸棒土对废弃食用油脂脱色的最佳条件:活性凹凸棒土质量分数15%,初始脱色温度60℃,终止脱色温度110℃,脱色时间20m in,凹凸棒土投放次数为1次,搅拌速度350 r/m in。