Effects of free fatty acids on oxidative stability of vegetable oil

1999 ◽  
Vol 76 (3) ◽  
pp. 325-329 ◽  
Author(s):  
N. Frega ◽  
M. Mozzon ◽  
G. Lercker
2021 ◽  
Vol 2 (1) ◽  
pp. 74-91
Author(s):  
Beatrice Casali ◽  
Elisabetta Brenna ◽  
Fabio Parmeggiani ◽  
Davide Tessaro ◽  
Francesca Tentori

The review will discuss the methods that have been optimized so far for the enzymatic hydrolysis of soapstock into enriched mixtures of free fatty acids, in order to offer a sustainable alternative to the procedure which is currently employed at the industrial level for converting soapstock into the by-product known as acid oil (or olein, i.e., free fatty acids removed from raw vegetable oil, dissolved in residual triglycerides). The further biocatalyzed manipulation of soapstock or of the corresponding acid oil for the production of biodiesel and fine chemicals (surfactants, plasticizers, and additives) will be described, with specific attention given to processes performed in continuous flow mode. The valorization of soapstock as carbon source in industrial lipase production will be also considered.


2021 ◽  
pp. 100166
Author(s):  
Carolina Medeiros Vicentini-Polette ◽  
Paulo Rodolfo Ramos ◽  
Cintia Bernardo Gonçalves ◽  
Alessandra Lopes De Oliveira

2020 ◽  
Vol 97 (8) ◽  
pp. 889-900 ◽  
Author(s):  
Ioan D. Fuller ◽  
Adam H. Cumming ◽  
Asli Card ◽  
Elaine J. Burgess ◽  
Colin J. Barrow ◽  
...  

2003 ◽  
Vol 2003 (1) ◽  
pp. 387-392 ◽  
Author(s):  
Zhengkai Li ◽  
Robert J. Downer ◽  
Brian A. Wrenn

ABSTRACT Floating vegetable oil can be effectively removed from the water surface and the water column as negatively buoyant oil-mineral aggregates by addition of a dense mineral, such as clay. In bench-scale experiments, it is possible to remove virtually all of the floating oil by addition of a sufficiently large dose of clay (>10 g clay/g oil). Once present in the sediments, vegetable oil can be completely transformed to harmless end products (e.g., carbon dioxide and methane) by naturally occurring microbial populations. Transient production of toxic intermediates (probably free fatty acids), measured as a reduction in sediment EC50 using the Microtox Solid-Phase Test (SPT), was observed during anaerobic biodegradation. The EC50 is the sediment concentration required to reduce light emission by bioluminescent bacteria by 50%. Addition of amorphous ferric hydroxide as an alternative electron acceptor stimulated the rate of vegetable oil biodegradation, but had no effect on the Microtox EC50. Alternative factors, including clay and calcium, were tested for their ability to reduce the transient toxicity by reducing the bioavailability of the free fatty acids. Calcium, and especially calcium plus clay, reduced the rate and extent of vegetable oil biodegradation but had no effect on the sediment toxicity as measured by the Microtox SPT. Only oil biodegradation significantly reduced the sediment toxicity.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Rosana Chirinos ◽  
Daniela Zorrilla ◽  
Ana Aguilar-Galvez ◽  
Romina Pedreschi ◽  
David Campos

The effect of roasting ofPlukenetia huayllabambanaseeds on the fatty acids, tocopherols, phytosterols, and phenolic compounds was evaluated. Additionally, the oxidative stability of the seed during roasting was evaluated through free fatty acids, peroxide, andp-anisidine values in the seed oil. Roasting conditions corresponded to 100, 120, 140, and 160°C for 10, 20, and 30 min, respectively. Results indicate that roasting temperatures higher than 120°C significantly affect the content of the studied components. The values of acidity, peroxide, andp-anisidine in the sacha inchi oil from roasted seeds increased during roasting. The treatment of 100°C for 10 min successfully maintained the evaluated bioactive compounds in the seed and quality of the oil, while guaranteeing a higher extraction yield. Our results indicate thatP. huayllabambanaseed should be roasted at temperatures not higher than 100°C for 10 min to obtain snacks with high levels of bioactive compounds and with high oxidative stability.


2020 ◽  
Vol 71 (3) ◽  
pp. 367
Author(s):  
A. Al-Farga ◽  
M. Baeshen ◽  
F. M. Aqlan ◽  
A. Siddeeg ◽  
M. Afifi ◽  
...  

This study investigated the effects of blending alhydwan seed oil and peanut oil as a way of enhancing the stability and chemical characteristics of plant seed oils and to discover more innovative foods of high nutraceutical value which can be used in other food production systems. Alhydwan seed oil and peanut oil blended at proportions of 10:90, 20:80, 30:70, 40:60 and 50:50 (v/v) were evaluated according to their physi­cochemical properties, including refractive index, relative density, saponification value, peroxide value, iodine value, free fatty acids, oxidative stability index, and tocopherol contents using various standard and published methods. At room temperature, all of the oil blends were in the liquid state. The physicochemical profiles of the blended oils showed significant decreases (p < 0.05) in peroxide value (6.97–6.02 meq O2/kg oil), refractive index at 25 °C (1.462–1.446), free fatty acids (2.29–1.71%), and saponification value (186.44–183.77 mg KOH/g), and increases in iodine value and relative density at 25 °C (98.10–102.89 and 0.89–0.91, respectively), especially with an analhydwan seed oil to peanut oil ratio of 10:90. Among the fatty acids, oleic and linoleic acids were most abundant in the 50:50 and 10:90 alhydwan seed oil to peanut oil blends, respectively. Oxidative stability increased as the proportion of alhydwan oil increased. In terms of tocopherol contents (γ, δ, and α), γ-tocopherol had the highest values across all of the blended proportions, followed by δ-tocopherol. The overall acceptability was good for all blends. The incorporation of alhydwan seed oil into peanut oil resulted in inexpensive, high-quality blended oil that may be useful in health food products and pharmaceuticals without compromising sensory characteristics.


2020 ◽  
Vol 4 (2) ◽  
pp. 76-85
Author(s):  
Abdelmalik M. Shakorfow ◽  
Abdulaziz. H. Mohamed

AbstractSeveral techniques, in which different homogenous catalysts and procedures, that are in use for transesterification of a vegetable oil or an animal fat have been successful in synthesizing biodiesel, although with some certain limitations. For such a purpose, among the catalysts employed are acidic as well as basic catalysts. It has been found that acidic catalysts can be tolerant with a high content of free fatty acids found in those low value feedstock oils/fats to be transesterified, although some sort of pretreatment by means of esterification might be required in order to synthesize biodiesel. Moreover, with employing homogenous acidic catalysts, it seems that biodiesel purification procedures are simplified; thus, reducing synthesis cost. In fact, these features of homogenous acidic catalysts render them advantageous over basic ones. With basic homogenous catalysts this; however, has not been possible due to the development of saponification reaction. To effectively perform, such catalysts require that the content of free fatty acids in the feedstock oil/fat is minimal. This requirement is also applicable to the moisture level in the feedstock. In terms of corrosive effects; nevertheless, acidic catalysts are disadvantageous compared to basic ones.


2020 ◽  
Vol 17 (98) ◽  
pp. 63-72 ◽  
Author(s):  
Dariush Khademi Shurmasti ◽  
Farid Shariatmadari ◽  
Mohammad Amir Karimi Torshizi ◽  
◽  
◽  
...  

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Philip Raine ◽  
Bennette Attipoe ◽  
Jeffrey Field

Abstract Objectives Degradation of oil is characterized by oxidation, polymerization and hydrolysis of the chemical compounds of the oil. This process of deterioration increases the amount of several types of compounds, including polar compounds, such as alcohols, ketones and free fatty acids. Currently, there is no universal assay for measuring the quality of frying oil, and tests that do exist to examine frying oil are often costly and time consuming. This study set out to examine the utility of Reichardt's dye, a solvatochromic dye that indicates degrees of solvent polarity, as a possible way to accurately predict the degree of degradation of cooking oils. Methods Several pH indicators were used to indicate the pH of the substances tested. Reichardt's dye was first tested against well-known indicators, including Bromophenol blue, Bromothymol blue, Bromocresol purple, and Phenolphthalein. One milliliter of each oil sample was combined with 0.5 milliliters of the Reichardt's dye solution and the color changes were observed. To determine the percentage of free fatty acids in each of the three oils, approximately 2 grams of oil with a pH indicator was dissolved in 100% ethanol and titrated with 1 M potassium hydroxide solution. The titrations assigned quantitative values to the color changes observed when Reichardt's dye was used. Results The addition of Reichardt's dye solution to all three oils indicated presence of polarized substances through varying degrees of color change whereby the fresh vegetable oil had the lowest concentration of polar compounds (dark blue) and the degraded oil had the highest concentration of polar compounds (greenish-orange). The degree of color change correlated with the results of titrations which demonstrated increasing amounts of free fatty acid (FFA) content in the fresh vegetable oil (0.17% FFA), the slightly degraded kitchen oil (2.7% FFA) and the degraded oil (15% FFA). Conclusions Our experiment showed that Reichardt's dye was effective in indicating the polarity of oil substances, a reflection of the degree of degradation in oil. Given that oxidized oil is harmful to health, it is important to measure this oxidation process. This study warrants future research into the utility of Reichardt's dye. Funding Sources National Institute of Environmental Health Sciences, NIH; University of Pennsylvania TREES Program (R25 ES021649).


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