American Oil Chemists Society Research Articles

A Comprehensive Study for Determination of Free Fatty Acids in Selected Biological Materials: A Review.

The quality of oil is highly dependent on its free fatty acid (FFA) content, especially due to increased restrictions on renewable fuels. As a result, there has been a growing interest in free fatty acid determination methods over the last few decades. While various standard methods are currently available, such as the American Oil Chemists Society (AOCS), International Union of Pure and Applied Chemistry (IUPAC), and Japan Oil Chemists' Society (JOCS), to obtain accurate results, there is a pressing need to investigate a fast, accurate, feasible, and eco-friendly methodology for determining FFA in biological materials. This is owing to inadequate characteristics of the methods, such as solvent consumption and reproducibility, among others. This study aims to investigate FFA determination methods to identify suitable approaches and introduce a fresh perspective.

Esterification effect on the recovery of vitamin E from palm oil refining residues by molecular distillation

AbstractWaste edible oils are an alternative source of high‐value natural compounds. Vitamin E can be recovered from palm oil refining residues by molecular distillation. However, the presence of other lipophilic molecules compromises the selective separation of vitamin E. Esterification of the free fatty acids can enhance the selective separation of vitamin E by molecular distillation, but the conditions for carrying out the reaction need to be investigated to simultaneously ensure the conversion of free fatty acids and the reduction of vitamin E losses. Thus, this study investigated the effect of the esterification of the industrial waste on the recovery of vitamin E by molecular distillation. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and analysis for fats and oils preconized by the American Oil Chemists' Society (AOCS) were used in the characterization of the industrial waste. Determination of the best condition to carry out the reaction was obtained by a central composite rotational design (CCRD) using the response surface methodology (RSM) and the desirability profile. The results showed that the best condition for the esterification was at 64°C, 213 min, 2 wt.% sulphuric acid, and a 10/1 methanol/free fatty acids molar ratio. This reaction condition achieved 97.9% conversion of free fatty acids and less than 3% of vitamin E loss. The esterification promoted concentration of vitamin E in the residue stream (145.4%) and reduction in the distillate stream (87.8%). Therefore, the obtained results presented a suitable route to obtaining vitamin E concentrate and adding value to an industrial residue.

Comparison of the nutrient composition of eggs produced in the Guatemalan highlands during the wet and dry seasons.

The potential of chicken eggs as a nutritionally complete protein and source of key micronutrients during the first 1000 days post-conception has been progressively recognized across the globe, particularly in resource-poor settings. Fluctuation of egg nutrient content by season is relatively unknown, which may influence international food composition databases and outcomes in intervention studies using egg supplementation. To better interpret the findings of The Saqmolo' Project, we conducted comprehensive nutrient analyses on eggs produced during the wet and dry seasons in the highlands of central Guatemala. We randomly collected 36 shell eggs from a local farm during both seasons, hard-boiled, and prepared them for transport to the United States, where they were pooled and assessed for their nutrient composition. Methods of the Association of Official Analytical Chemists, the American Oil Chemists Society, and the American Association of Cereal Chemists were utilized to determine total energy, moisture, ash, total protein, total fat, fatty acids, total carbohydrates, 12 vitamins, 11 minerals, and carotenoids, by season, in some instances with modifications. Differences in nutrient composition between de-shelled hard-boiled eggs collected between seasons were assessed using an analysis of variance (ANOVA) and Tukey's family error rate comparison test. Most nutrients in eggs produced in the highlands of central Guatemala differed negligibly (but statistically significantly) based on seasonality. Only vitamins A and E, folate, choline, and calcium fluctuated at clinically significant levels relative to the AI/RDA for infants 7-12 months. Total energy, protein, trans fatty acids, moisture, and vitamin D3 levels did not differ between seasons (p > .05). Further multi-year sampling is needed to examine how seasonal variation affects the nutrient composition of eggs. These data may be used to supplement existing national and regional food composition databases.

Wijs, Potassium Iodate, and AOCS Official Method to Determine the Iodine Value (IV) of Fat and Oil

Fatty acid, present in edible oil, is a key constituent in our diet. The iodine number is a measure of the amount of unsaturated fatty acid in fat and oil. Iodine is a trace element that is required by humans for normal biological function. The iodine value (IV) of four edible oils was determined in this study: castor oil, peppermint oil, almond oil, and coconut oil. Iodine is a wonderful reagent for converting the unsaturation into the saturation of fat and oil. The purported technique offered a reliable and rapid determination of IV. The Wijs, or iodine monochloride, potassium iodate, and American Oil Chemists' Society's (AOCS) Fourier transform infrared spectroscopy (FT-IR) are all used to determine IV. Both Wijs and potassium iodate are iodometry-based titrations, whereas the AOCS method is applied through FT-IR. C=C stretching in the range of 1635.48cm-1-1652.77 cm-1, C=O band in the range of 1744.23 cm-1- 1747.49 cm-1, C-H stretching in the range of 2923.9 cm-1- 2925.85 cm-1, O-H stretching in the range of 3448 cm-1- 3472 cm-1 were observed in different dilution for identification of unsaturated fatty acid in numerous oils through FT-IR. All methods are satisfactory; meanwhile, the potassium iodate method is safer than the Wijs method experimentally and more economical than the AOCS method. IV for castor oil, peppermint oil, almond oil, and coconut oil were computed at 84.67 I2/100g,5.56 I2/100gm,99.09 I2/100gm,8.21 I2/100gm along with the deviation by three methods.

Enabling chlorophyll photo-response for in-line real-time noninvasive direct probing of the quality of palm-oil during mill process

During the milling process of palm oil, the degree of palm fruit ripeness is a critical factor that affects the quality and quantity of the oil. As the palm fruit matures, its chlorophyll level decreases, and since chlorophyll in oil has undesirable effects on hydrogenation, bleachability, and oxidative degradation, it’s important to monitor the chlorophyll content in palm oil during the milling process. This study investigated the use of light-induced chlorophyll fluorescence (LICF) for non-invasive and real-time monitoring of chlorophyll content in diluted crude palm oil (DCO) located at the dilution and oil classification point in palm oil mill. An LICF probe was installed at the secondary pipe connected to main DCO pipeline, and the system communicates with a computer located in a separate control room via a Wi-Fi connection. Continuous measurements were recorded with an integration time of 500 ms, averaging of 10, and a time interval of 1 min between each recording during the oil mill’s operation. All data were stored on the computer and in the cloud. We collected 60 DCO samples and sent them to the laboratory for American Oil Chemists’ Society (AOCS) measurement to compare with the LICF signal. The LICF method achieved a correlation coefficient of 0.88 with the AOCS measurements, and it also provided a direct, quantitative, and unbiased assessment of the fruit ripeness in the mill. By incorporating Internet of Things (IoT) sensors and cloud storage, this LICF system enables remote and real-time access to data for chemometrics analysis.

Oxidative and Frying Stabilities of Monodora myristica (Gaertn.) Du-nal Seed Oil of Nigerian Origin

Background: The demand for vegetable oils is on the increase. Deep frying is the commonest method by which vegetable oils are consumed. The aim of this study was to extract oil from an underutilized oil seed and compare its physicochemical properties, frying, and oxidative stability with those of commercial refined palm oil.
 Methods: Oil was extracted from Monodora myristica seeds using a soxhlet fat extractor and the percentage oil yield was determined. The physicochemical, oxidative, and frying stabilities of the extracted M. myristica Seed Oil (MMSO) were evaluated based on the standard procedure of the Association of Official Agricultural Chemists and official methods and recommended practices of the American Oil Chemists Society and compared with those of commercial refined palm oil- Kings Vegetable Oil (KVO). Data were statistically analyzed using SPSS version 20.
 Results: The oil yield of M. myristica seed was 37.64%. The refractive index, specific gravity, moisture content (%), and peroxide value (mEq/kg) were respectively 1.470, 1.468, 0.923, and 0.917 for MMSO; and 0.220, 0.253, 1.05, and 3.50 for KVO. MMSO had better oxidative stability and showed 80% lesser peroxide formation than KVO. The frying stability of MMSO was better as it showed a lower increase in FFA (28.4%) and peroxide value (9.54 mEq/kg) than KVO (45.99% and 26.19 mEq/kg, respectively) after frying.
 Conclusion: Deteriorative effect of oxidation and polymerization was lower in MMSO than in KVO indicating MMSO to be superior frying oil suitable for repeated frying.

A fast and cost-effective procedure for reliable measurement of trypsin inhibitor activity in soy and soy products.

Rapid and accurate measurement of trypsin inhibitor is critical for soy processors to assess the quality of soy meal. Currently, trypsin inhibitor activity is measured using the American Oil Chemists' Society (AOCS) and the American Association of Cereal Chemists International (AACCI) approved method. We have modified and improved the AACCI/AOCS approved method resulting in the elimination of several time-consuming steps and drastically reducing the assay volume. By employing our simplified procedure, we have measured trypsin inhibitor activity of several soy and soy products. A side-by side comparison of our simplified procedure with AOCS approved method revealed strikingly similar results indicating that several time-consuming and tedious steps associated with AACCI/AOCS approved methods can be eliminated without sacrificing the accuracy of the assay. Moreover, we demonstrate that our assay can also be carried out in 96-well microplates which will enable high-throughput screening of large number of soy meal samples.

Characterization of the Physicochemical Properties of Virgin and Used Vegetable Oil

Vegetable oils form a vital part of the diet in many homes. The repeated use of same oil for deep frying is widespread in commercial as well as domestic cooking processes. This study aimed at investigating the physicochemical properties of popular brands of virgin and used edible oils sold in Nigeria to ascertain the effects of using the same oil for repeated frying. Standard methods prescribed by the Association of Analytical Chemists (AOAC) and American oil Chemists Society recommended practice (AOCS) were used to determine relative density (RD), peroxide value (PV), iodine value (IV), acid value (AV), free fatty acid (FFA), volatile matter (VM), viscosity (VY) and insoluble impurities (IP). Results revealed that the temperature change in the oil samples induced a difference in their RDs, AVs and PVs. This was also observed in the proportions of the FFA content of the oil samples before they were used and after two frying cycles. PVs in the study ranged from 1.40 - 13.60 meqO2/kg; IVs ranged from 48.22-118.02 gI2/100g; RDs ranged from 0.91 -0.95 kg/l; AV ranged from 1.37 - 49.56 mgKOH/g; FFA ranged from 0.59 - 11.56%; VM range was 0.0003 to 0.0484 %. VY range was 136.04 -220.53 mgKOH/g and IPs ranged from 5.03 - 9.02 %.

Analysis of Physical and Chemical Properties of Dammar Resin as an Alternative Fuel

Efforts to obtain alternative and renewable energy continue to be carried out sustainably. Various natural materials continue to be studied for their feasibility in using alternative and renewable fuels. One of the natural materials that have the potential as a source of renewable energy is dammar resin (Shorea Javanica k. et v.). Therefore, it is necessary to analyze dammar resin's physical and chemical properties to determine its potential as an alternative fuel. This study evaluates dammar resin's physical and chemical properties as a renewable energy source. In this research, the physical and chemical properties of dammar resin were investigated related to its function as an alternative fuel compared to other alternative fuels. This study also aims to determine the advantages and disadvantages of dammar resin's physical and chemical properties as an alternative fuel. The American Society for Testing and Materials standard (ASTM), International Organization for Standardization (ISO), and the American Oil Chemists Society standard (AOCS) methods have been adopted to analyze the physical and chemical properties of dammar resins. This study's physical and chemical properties were cloud point, pour point, flash point, density, energy content, ash content, sulfur content, iodine value, saponification value, and cetane number. The result indicates that based on the physical and chemical property analysis, dammar resin has potency as a renewable energy source and can be developed as an alternative fuel. Dammar resin has a low flash point, sulfur content, and iodine value but a high saponification value and cetane number; these values have met European requirements. Moreover, the energy content of dammar resin is lower, and the ash content is higher than other biodiesel materials. However, dammar resin still requires advanced processes to be converted as alternative energy because it still has a high density, cloud, and pour point.

Comparison of ISO 14902:2001 with AOCS Ba 12a‐2020 for determining trypsin inhibitor activity in protein products

AbstractFor measuring trypsin inhibitor activity (TIA), there are two major official methods: American Oil Chemists Society (AOCS) method Ba 12a‐2020 and International Organization for Standardization (ISO) 14902:2001. The former was recently approved. The two methods differ in sample preparation, extraction, colorimetric assay systems and TIA calculations. In this study, the two methods were symmetrically compared using three unique sets of samples: assorted protein products of soybeans, pulses, and grains; soybeans boiled for varied durations; and soy white flakes toasted for varied durations. For given samples, significant differences existed in TIA measured by the two methods, resulting from effects related to the assay systems and TIA calculations, not from the difference in sample preparation and extraction. When the same trypsin was used, TIA (in mg trypsin inhibited/g sample) measured by the two methods were highly correlated (r = 0.9973, n = 27), giving an equation of y = 0.5464x − 0.4887, where y represents ISO values and x for AOCS values. The line connecting ratios of ISO/AOCS in TIA and AOCS values remained relatively flat around 0.53 but started to curve down when TIA approached the lowest. Furthermore, for the same samples, TIA values measured by the ISO method decreased with increasing specific activity of trypsin used, while AOCS values remained consistent, leading to decreasing ratios of ISO/AOCS. Therefore, accurate and direct comparison of the two methods was impossible. It could not be resolved by simply changing ISO method's calculations as hypothesized earlier. Regardless, for most samples, ISO values were roughly about 55% of AOCS values.

EVALUATION OF ALLANBLACKIA FLORIBUNDA SEED OIL FOR POTENTIAL USE IN SOAP MAKING.

Allanblackia floribunda seed oil was extracted and used for soap production, as an alternative to palm oil and other frequently used vegetable oils in industries. The physico-chemical properties of the oil in terms of density, melting point, saponification value and iodine value were measured using American oil chemists’ society (AOCS) standard methods. Medicated Allanblackia floribunda soap was produced by reaction of the oil produced with caustic soda, water, pine oil, chloroxylenol, colour, fillers of different percentages. The physiochemical parameter measured show that the oil has iodine value of 39, melting point of 37 0C, density of 0.914 g/ml, peroxide value of 0.86 mEq/kg, saponification value of 198 mgKOH/g, moisture content of 0.16 % and percentage free fatty acid of 1.15%. The values of the physico-chemical properties of Allanblackia soap made were: soap weight = 81.8 g, soap texture - soft, foam height = 59.6 ml, percentage moisture content = 8.56 %, percentage free caustic alkali = 0.01 %, percentage alcohol insoluble matter = 4.0 %, percentage water insoluble matter = 1.6 % and percentage total fatty matter = 72.0 %. There were little deviations in the values of the parameters of the soap produced with the Allanblackia floribunda seed oil from that of the commercial medicated soaps (tetmosol and dettol) analysed. The results from the study show that the soap produced from Allanblackia floribunda seed oil is good and can serve as an alternative to palm oil.

Identification of olfactory characteristics of edible oil during storage period using metal oxide semiconductor sensor signals and ANN methods

In this study, an electronic nose coupled with artificial neural network (ANN) was used to predict the shelf life of two oil with new production date and oil with old production date over a period of 150 days. According to the American Oil Chemists’ Society results, the oils were oxidized after 60 days. Principal component analysis results indicated that all the oil samples were correctly discriminated from each other during their storage times, and samples of oxidized and nonoxidized oils can be properly distinguished from each other. Two main components (PC1, PC2) managed to describe 97% of the data set variance concerning the shelf life of the oil. To develop the ANN models, the data were first divided into three groups: training (60%), validation, and test (40%). To determine the best model, two criteria (R2 and root mean square error) were used. The results revealed that the ANN model can be used as a powerful tool for pattern recognition and determination of the shelf life of oil and its oxidation degree at high precision. Scientific and feasible results can be obtained by matching ANN and the results obtained by metal oxide semiconductor sensors of E-nose. Practical applications One of the most important causes of food spoilage is lipid oxidation. The American Oil Chemists’ Society (AOCS) has developed a variety of methods for assessing the state of food oxidation. In this study, oil shelf life studied by a combination of artificial senses and chemometrics methods. The acidity, peroxide, anisidine, and Totox values of the edible oil samples were measured according to the AOCS standard. Principal component analysis and artificial neural neural methods succeeded in classifying the samples based on their storage time with high accuracy.

Glycidol and 3‐MCPD Analysis Methods for Mono‐ and Diglycerides

AbstractDistilled monoglycerides (DMG) and mono‐di‐glycerides (MDG) are commonly used as emulsifiers in various processed foods, e.g., bread, margarine, and ice cream. DMG and MDG are derived from triacylglyceride (TAG) oils, and thus it is speculated that the harmful substances glycidol and 3‐monochloropropane‐1,2‐diol (MCPD) or their esters can also appear in DMG and MDG as they do in edible oil. However, present analysis methods, often developed for MCPD esters and glycidyl esters in TAG oils are not suitable for many DMG and MDG products. Dissolution of the DMG and MDG is the main problem. In this work a method for quantifying content of glycidol esters (GE) and 3‐MCPD using an indirect method quantifying the compounds with GC‐MS has been tested. The development has been developed based on the American Oil Chemists' Society (AOCS) Cd 29c method including the modifications implemented by Axel Semrau in the automated procedure for triglycerides. With the proposed procedure it is shown that the new analysis method produces valid results in the range 1–10 ppm, and acceptable results at 0.5 ppm for both 3‐MCPD and glycidol. The method is an important part of providing safe and healthy emulsifier improved food products to consumers in European Commission and the rest of the world.Practical Applications: The European Commission (EU) has requested the emulsifier industry to supply data for GE and MCPD content as a first step in making legislation for maximum content as in edible oils and fats. However, there is no analysis method for emulsifiers (e.g., mono‐ and diglycerides). This work is a contribution to development of such an analysis method.

Compact low-field NMR spectroscopy and chemometrics applied to the analysis of edible oils

Compact nuclear magnetic resonance (NMR) spectroscopy combined with chemometric tools opens new perspectives for NMR use. This work compares the potential of 43, 60 and 400 MHz NMR spectroscopy for quality control of edible oils. Partial least squares regression (PLSR) and support vector regression (SVR) models built on the three NMR devices had equivalent performances for fatty acids and iodine value, and the models built with the low field spectra were equivalent to the high field. Moreover, performances for calibration indicated that most of the models built with medium/or high-resolution fields presented reproducibility values lower than the minimum accepted by the American Oil Chemists' Society (AOCS). Compared to classical methods, this new approach allows the application of medium resolution devices as a sample screening tool in analytical laboratories since it allows the spectrum obtention in a few seconds, without the need for sample preparation or the use of deuterated solvents.

Extraction of Rice Bran Oil from Rice Bran by Supercritical Carbon Dioxide

Extraction of Rice Bran Oil from Rice Bran by Supercritical Carbon Dioxide

An International Collaborative Study on Trypsin Inhibitor Assay for Legumes, Cereals, and Related Products

AbstractFor determining trypsin inhibitor activity (TIA) in soy products, the American Oil Chemists' Society (AOCS) Method Ba 12‐75 has been used. It measures differences in absorbance at 410 nm of bovine trypsin activity toward a synthetic substrate (Nα‐benzoyl‐DL‐arginine‐p‐nitroanilide) in the absence and presence of an inhibitor. Recently, a significantly improved method was developed (JAOCS, 2019, 96:635–645), featuring 5 mL of total assay volume, enzyme‐last sequence, and single inhibitor level in duplicate. It is proposed as the AOCS Method Ba 12a‐2020. As a part of the AOCS method approval process, a collaborative study involving 12 international laboratories was conducted to evaluate the performance of the proposed method. The study involved measuring TIA in 10 selected test samples plus a blind duplicate. They included soybeans, pulses, cereals, and their processed products (flours, concentrates, and isolates). After rigorous statistical treatment of the data, only three outliers were removed from the data of two samples. Repeatability relative standard deviations (RSDr) for the 11 samples ranged from 0.99% to 5.52%. Reproducibility RSD (RSDR) ranged from 7.07% to 22.92%, with seven samples having RSDR around 10% or less. The remaining four samples had very low TIA, and their RSDR values ranged from 13.34% to 22.92%. The study has demonstrated reliable performance of the proposed AOCS method. Several collaborators carried out additional experiments addressing some aspects of the method, leading to further refinements. The proposed method is undergoing evaluation by the AOCS Uniform Methods Committee for adoption as an Official Method for measuring TIA in various legume and grain products.

In-Situ Epoxidation of Waste Cooking Oil and Its Methyl Esters for Lubricant Applications: Characterization and Rheology

In the present investigation, in-situ epoxidation of waste cooking oil and its methyl esters was prepared, and the rheological behavior was analyzed for biolubricant applications. Rheological properties of the prepared epoxides were measured at a temperature of 25–100 °C, at a shear rate ranging from 5 to 300 s−1. As viscosity is one of the critical parameters for potential biolubricant applications, in the present study, the power-law model was used to investigate the flow behavior of the epoxides. The viscosity of epoxidized waste cooking oil and its methyl ester epoxides showed Newtonian flow behavior in the studied temperature range. Different shear rates (5–100, 5–300, 100–300 s−1) were studied to determine the shear rate dependency of the epoxidized waste cooking oil and its methyl ester epoxides at different temperatures. From the average viscosity values, it was shown that the epoxides show identical results at all shear rates. The dynamic viscosities of the epoxidized waste cooking oil and its methyl ester epoxides were found to be dependent on fatty acid chain length, unsaturation, and temperature. Detailed physicochemical characterization for epoxide waste cooking oil (EWCO) and epoxide waste cooking oil methyl esters (EWCOME) were carried out to evaluate the properties for suitable biolubricant applications using standard American Society for Testing and Materials (ASTM) and American Oil Chemists’ Society (AOCS) methods. Based on the viscosity for EWCO (278.9 mm2/s) and EWCOME (12.15 mm2/s) and viscosity index for EWCO (164.94) and EWCOME (151.97) of the prepared epoxides, they could complement the standard ISO vegetable grade (VG) lubricants in the market.

The COVID-19 pandemic, one year later

When shutdowns began in the spring of 2020, we thought we might have to work from home for a couple of weeks to let the spread of the novel corona virus subside. Avoiding the daily commute was a nice change of pace at first, but then weeks turned into months. As the year dragged on, we realized the myriad things we took for granted in our pre-COVID lives: health, human contact, childcare, collaboration…the list goes on. © 2021, American Oil Chemists Society. All rights reserved.

The green machine: commercializing microalgae products

Sales of plant-based foods are booming. The growing popularity of non-animal protein sources has led to their increased presence in grocery stores and fast-food restaurants. Even while venture capital investments declined due to the COVID-19 pandemic, start-ups focused on plant-based ingredients raised millions (https://tinyurl.com/plantbasedinvestments). In the Netherlands alone, there are more than 60 companies dedicated to the development of plant-based proteins (https:// tinyurl.com/netherlandsplantbased). With so much lucrative potential in plant-based ingredients, some companies are trying to capitalize on algae as a unique source of protein and fatty acids. © 2021, American Oil Chemists Society. All rights reserved.

The Influence of Oil Raw Materials on The Quality of Finished Soap Products in The Laboratory Division at PT. Solar Wings Corps

The business actors are required to generate the maximum profit possible, thus demanding workers to work productively. This cannot be denied because workers are the most essential element in running the company’s wheels. PT Wings Surya is a manufacturing company that produce soap. this research activity focuses on how to check soap products using the AOCS Method, in which the AOCS (The American Oil Chemists’ Society) method is a method applied to measure and analyze levels in oil so that it is known whether these levels already meet the standards to be processed into a quality product. The quality of the finished soap product can be determined and anticipated by looking at the quality of the Iodide Value, Peroxide Value, and Saponification Value of the raw oil used for the soap product. The finished product of soap at PT. Wings Surya in November based on the quality of the raw material used, it will produce a finished product of soap with good quality but not with the rancid smell caused by the raw material of the oil it self.