Estimation of conjugated octadecatrienes in edible fats and oils (original) (raw)

Nutritional Characteristics of Oil Containing Conjugated Octadecatrienoic Fatty Acid

Annals of Nutrition and Metabolism, 1998

The nutritive value of conjugated octadecatrienoic fatty acid (C18:3 Δ9,11,13α-elaeostearic acid) as occurs in karela seed (Momordica charantia) oil was studied. When rats were fed at the 20% level for 6 weeks, the growth pattern of rats and the food efficiency ratio showed a slightly significant difference compared to the group raised on linseed oil with non-conjugated octadecatrienoic acid (C18:3 Δ9,12,15α-linolenic acid) as control. The concentrations of total cholesterol, triglyceride, VLDL-cholesterol, LDL-cholesterol and LDL/HDL-cholesterol in serum were significantly higher in karela oil than in linseed oil. The liver lipid profile showed no difference. The total lipid as well as phospholipid concentrations of heart lipid were significantly higher in karela oil. The brain weight of the linseed oil group was significantly higher than the karela group. The brain phospholipid concentration of the karela oil group was significantly higher than that of the linseed oil group.

Edible Fats and Oils

There is a lipid oxidation problem in edible oils and fats due to the fact that they are continuously exposed to various storage conditions or overheating. Therefore, investigation of the stabilization of edible oil products is an area worth researching due to consumer-related health concerns. Consequently, thermal oxidative deterioration might be prevented if the stability of the product is comprehended fairly. Thus, food formulations can be regulated depending on the findings of the stability measurements. In this review article, the mechanism and structure of lipid oxidation process have been explained. Furthermore, the significance of prediction of shelf-life has been mentioned as well as kinetic and thermodynamic comprehension in oxidation process. Additionally, all the mentioned stability measuring methods have been discussed, respectively.

Chemical and physiological aspects of isomers of conjugated fatty acids

Food Science and Technology (Campinas), 2010

Lifestyle factors, including diet, influence the development of many non transmissible chronic diseases such as cancer, atherosclerosis, inflammation, and obesity (PARK; PARIZA, 2007). The human diet contains saturated, monounsaturated and omega-3 and omega-6 polyunsaturated fatty acids (YANG et al., 2009). In addition, two types of structurally related conjugated octadecaenoic acids, namely, conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLNAs), are also present in the human diet although in small quantities (YANG et al., 2009). It has been noted that the quality of dietary lipids could be an important modulator in terms of the morbidity and mortality of these diseases (NAGAO; YANAGITA, 2005). Polyunsaturated fatty acids (PUFAs), such as linoleic acid (LA, 18:2, ω-6), α-linolenic acid (LNA, 18:3, ω-3), and arachidonic acid (20:4, ω-6) are important for the maintenance of biofunctions in mammals. It should be also noted that other polyunsaturated fatty acids of omega-series such as eicosapentaenoic acid (EPA, 20:5, ω-3) and docosahexaenoic acid (DHA, 22:6, ω-3) are correlated with a reduced risk of cancer and cardiovascular disease in clinical and animal studies (NAGAO; YANAGITA, 2008). Recently, many studies are focused on 'conjugated fatty acids' (CFAs), which is the general term for a set of positional and geometric isomers of polyunsaturated fatty acids with conjugated double bonds (YUAN, G. F.; YUAN, J. Q.; LI, 2009; YUAN et al., 2009a). Interest in health benefits of CFAs is increasing since they have been shown to possess antioxidant, antitumor, immunomodulatory, and serum lipid-lowering activity (CAO et al., 2009). According to Tran et al. (2010), CFAs are known to have pharmacologic activities relevant to the prevention and treatment of atherosclerosis, obesity, cancer, and hypertension. CFAs occur naturally as diene, triene, and tetraene compounds (YUAN, G. F.; YUAN, J. Q.; LI, 2009; YUAN et al., 2009a, c). Theoretically, several CFA isomers are possible with multiple combinations of numerical, positional, and geometrical configurations of conjugation in double bonds Resumo Ácido graxo conjugado (AGC) é o termo geral usado para descrever os isômeros posicionais e geométricos dos ácidos graxos poliinsaturados com duplas ligações conjugadas. Os AGCs do ácido linoléico (ALCs) são encontrados naturalmente em alimentos derivados de animais ruminantes, carnes e produtos lácteos. Os AGCs do ácido α-linolênico (ALNCs) são encontrados exclusivamente em óleos de sementes de vários tipos de plantas. Desenvolvem-se muitas investigações com o objetivo de avaliar os efeitos do consumo de AGCs para a saúde, já que estes têm sido associados a processos fisiológicos relacionados com doenças crônicas não transmissíveis como câncer, aterosclerose, inflamação e obesidade. Estudos conclusivos sobre os efeitos dos AGCs no organismo humano ainda são raros e mais pesquisas sobre sua atuação em processos fisiológicos são necessárias. O objetivo desta revisão é discutir a influência dos ácidos graxos conjugados sobre os processos fisiológicos. Palavras-chave: ácido linoléico conjugado (ALCs); ácido α-linolênico conjugado (ALNCs); efeitos à saúde; análises.

Monocyclic saturated fatty acids formed from oleic acid in heated sunflower oils

Chemistry and Physics of Lipids, 1996

Fractions of saturated cyclic fatty acids, formed from oleic acid in normal and high-oleate sunflower oils during small-scale frying operations, were isolated by silver ion high-performance liquid chromatography. By means of gas chromatography of the methyl esters and gas chromatography/mass spectrometry of the dimethyloxazoline derivatives, eight monocyclic saturated fatty acids, comprising four basic structures, were identified: cyclopentyl fatty acids with rings from C 5 to C-9 and C-10 to C-14, and cyclohexyl fatty acids with rings from C 4 to C-9 and C-10 to C 15 of the original fatty acid chain. Each structure was represented by two components corresponding to cis and trans ring isomers. The cyclopentyl fatty acids were twice as abundant as those with a cyclohexane ring. Possible mechanisms for formation of the cyclic fatty acids via radical intermediates are discussed.

Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements

Food & Nutrition Research, 2011

There is convincing evidence that replacing dietary saturated fats with polyunsaturated fats (PUFA) decreases risk of cardiovascular diseases. Therefore, PUFA rich foods such as vegetable oils, fatty fish, and marine omega-3 supplements are recommended. However, PUFA are easily oxidizable and there is concern about possible negative health effects from intake of oxidized lipids. Little is known about the degree of lipid oxidation in such products. To assess the content of lipid oxidation products in a large selection of vegetable oils and marine omega-3 supplements available in Norway. Both fresh and heated vegetable oils were studied. A large selection of commercially available vegetable oils and marine omega-3 supplements was purchased from grocery stores, pharmacies, and health food stores in Norway. The content of lipid oxidation products were measured as peroxide value and alkenal concentration. Twelve different vegetable oils were heated for a temperature (225°C) and time (25 minutes) resembling conditions typically used during cooking. The peroxide values were in the range 1.04-10.38 meq/kg for omega-3 supplements and in the range 0.60-5.33 meq/kg for fresh vegetable oils. The concentration range of alkenals was 158.23-932.19 nmol/mL for omega-3 supplements and 33.24-119.04 nmol/mL for vegetable oils. After heating, a 2.9-11.2 fold increase in alkenal concentration was observed for vegetable oils. The contents of hydroperoxides and alkenals in omega-3 supplements are higher than in vegetable oils. After heating vegetable oils, a large increase in alkenal concentration was observed.

Rapid Method for Extracting and Quantifying Synthetic Antioxidants in All Edible Fats and Oils

Food Analytical Methods, 2016

A simple, rapid, and accurate analytical method was applied to the quantification synthetic antioxidants (SAs) in all kinds of fats and oils, including propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT). Moreover, the activity and function of the added SAs to edible oils were evaluated by quantifying oxidative stability (OS) and peroxide value (PV) of the test samples. For the quantification of SAs, high performance liquid chromatography (HPLC) with the gradient method was applied. Under the recommended conditions, the separation of four SAs was achieved in less than 14 min. In this method, the SAs were extracted from the edible oils using methanol/ acetonitrile (1:1, (v/v)). The mixture was subjected to vortex/ ultrasonic treatment. The extracts were next kept in a freezer (−20°C) for 1 h. The upper layer was injected into HPLC. The recovery value of each SA was obtained in the ranges of 89.95-100.38 % for PG, 96.45-100.10 % for TBHQ, 91.57-98.80 % for BHA, and 90.23-95.56 % for BHT. The method was applied for the evaluation of SAs in 57 samples of fats and oils such as sunflower, canola, frying, hydrogenated, soybean, olive, margarine, blended oils, animal butter, and butter oils. The amount of each SA in the test samples was in the legal standard limit set for SAs in the National Standards of Iran (INSO 3608). Results showed that OS was directly related to the amount of SAs and inversely related to PV in all the test samples. PG and TBHQ were detected in almost all margarine and all edible oil samples, respectively.