scholarly journals NMR Determination of Free Fatty Acids in Vegetable Oils

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 410 ◽  
Author(s):  
Maria Enrica Di Pietro ◽  
Alberto Mannu ◽  
Andrea Mele
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Vegetable Oils ◽  
31P Nmr ◽  
Waste Cooking Oils ◽  
Pros And Cons ◽  
Application Fields ◽  
Cooking Oils ◽  
13C And 31P Nmr

The identification and quantification of free fatty acids (FFA) in edible and non-edible vegetable oils, including waste cooking oils, is a crucial index to assess their quality and drives their use in different application fields. NMR spectroscopy represents an alternative tool to conventional methods for the determination of FFA content, providing us with interesting advantages. Here the approaches reported in the literature based on 1H, 13C and 31P NMR are illustrated and compared, highlighting the pros and cons of the suggested strategies.

Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins

Fuel ◽  
2008 ◽  
Vol 87 (10-11) ◽  
pp. 1789-1798 ◽  
Author(s):  
Nalan Özbay ◽  
Nuray Oktar ◽  
N. Alper Tapan
Keyword(s):  
Fatty Acids ◽  
Ion Exchange ◽  
Free Fatty Acids ◽  
Ion Exchange Resins ◽  
Waste Cooking Oils ◽  
Exchange Resins ◽  
Cooking Oils

scholarly journals pH-Metric Determination of the Acid Value of Vegetable Oils without Titration

1998 ◽  
Vol 81 (4) ◽  
pp. 873-879 ◽  
Author(s):  
Ilya Kuselman ◽  
Yakov I Tur’yan ◽  
Oleg Y Berezin ◽  
Lina Kogan ◽  
Avinoam Shenhar
Keyword(s):  
Fatty Acids ◽  
Quality Control ◽  
Free Fatty Acids ◽  
Vegetable Oils ◽  
Isopropyl Alcohol ◽  
Acid Value ◽  
Standard Acid ◽  
Initial Ph ◽  
The Difference

Abstract The acid value (AV) of vegetable oils is determined without titration by using a new reagent consisting of triethanolamine in a solution of water and isopropyl alcohol. When the oil sample is mixed with the reagent in the pH-metric cell, free fatty acids from the sample are extracted into the reagent ( 3 - 4 min). The initial pH, called conditional pH´, is measured, a standard acid (HC1) is added, and the final pH, pH´2, is measured. AV is calculated from the difference between pH´! and pH´2. The method is applicable for quality control of vegetable oils during their production, trade, and use

Detection of Adulterated Vegetable Oils Containing Waste Cooking Oils Based on the Contents and Ratios of Cholesterol, β-Sitosterol, and Campesterol by Gas Chromatography/Mass Spectrometry

2015 ◽  
Vol 98 (6) ◽  
pp. 1645-1654 ◽  
Author(s):  
Haixiang Zhao ◽  
Yongli Wang ◽  
Xiuli Xu ◽  
Heling Ren ◽  
Li Li ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Vegetable Oils ◽  
Waste Cooking Oil ◽  
Gas Chromatography Mass Spectrometry ◽  
Quick Method ◽  
Cooking Oil ◽  
Waste Cooking Oils ◽  
Cooking Oils

Abstract A simple and accurate authentication method for the detection of adulterated vegetable oils that contain waste cooking oil (WCO) was developed. This method is based on the determination of cholesterol, β-sitosterol, and campesterol in vegetable oils and WCO by GC/MS without any derivatization. A total of 148 samples involving 12 types of vegetable oil and WCO were analyzed. According to the results, the contents and ratios of cholesterol, β-sitosterol, and campesterol were found to be criteria for detecting vegetable oils adulterated with WCO. This method could accurately detect adulterated vegetable oils containing 5% refined WCO. The developed method has been successfully applied to multilaboratory analysis of 81 oil samples. Seventy-five samples were analyzed correctly, and only six adulterated samples could not be detected. This method could not yet be used for detection of vegetable oils adulterated with WCO that are used for frying non-animal foods. It provides a quick method for detecting adulterated edible vegetable oils containing WCO.

scholarly journals Production of biodiesel by esterification and transesterification from waste cooking oils

2020 ◽  
Vol 38 (1) ◽  
pp. 105-127
Author(s):  
Elsy Arenas ◽  
Aidin Urribarrí ◽  
John Sánchez ◽  
Marisela Rincón ◽  
Karina Martínez ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Fast Food ◽  
Methyl Esters ◽  
Reaction Times ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Waste Cooking Oils ◽  
Hcl Concentration ◽  
Cooking Oils

Large quantities of used vegetable oils (AVUs) are generated annually, as a result of food preparation, which can cause contamination of waters and soils, if they are not disposed of properly, but in turn have great potential in the production of biodiesel. In this work, the AVU collected from fast food establishments were subjected to an esterification pretreatment, varying the reaction conditions, molar ratio, catalyst concentration and time, to decrease the content of free fatty acids generated in the frying processes; after an alkaline transesterification. The initial acidity of the AVUs (10,08 ± 0,22 %) was found to drop below 1 % during esterification at 60 °C and 100 rpm, with RMAVU:MeOH of 1: 7 and HCl concentration of 0.3 % v/v, with a conversion of free fatty acids (FFA) to methyl esters of 94.48 and 98.61 % for reaction times of 4 and 6 hours, respectively. The previously esterified AVUs were subjected to a transesterification process with KOH as a catalyst in the presence of methanol, at 60 °C and 100 rpm, finding that the biodiesel produced was a mixture composed of the methyl esters of linoleic acids (57 %), palmitic (14 %), oleic (22 %), stearic (4 %) and elaidic (3 %). The highest concentration of methyl esters (93,797 ± 0.685 g.L-1) was obtained when using the esterified AVU during 6 hours of reaction. FTIR spectra confirmed the conversion of fatty acids to methyl esters, so this product could be used as a biofuel.

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