Elsevier

Food Control

Volume 48, February 2015, Pages 155-162
Food Control

Influence of deep-fat frying process on phospholipid molecular species composition of Sardina pilchardus fillet

https://doi.org/10.1016/j.foodcont.2014.06.005Get rights and content

Highlights

  • Analysis of phospholipid play a key role on the control of the fried fish quality.

  • Frying led to a significant change on fish phospholipid molecular species profile.

  • Phosphatidylcholine profile was more affected by the frying than phosphatidylethanolamine.

  • Phosphatidylcholine profile changed according to the nature of frying oil.

  • Frying temperature had no effect on all phospholipid profiles.

Abstract

The effects of deep-fat frying performed using different culinary fats (extra virgin olive oil, conventional sunflower oil and high-oleic sunflower oil) and different frying temperatures (160 and 180 °C) on the composition of the preponderant fish phospholipid classes, phosphatidylethanolamine (PE) and phosphatidylcholine (PC), were investigated on Sardina pilchardus. The total fish lipid fraction was injected into the HPLC system coupled on line with a second order mass spectrometer (MS–MS) by means of electronebulization interface (ESI), without a prior clean-up of the phospholipid fraction.

The deep-fat frying process caused significant changes on PE and PC molecular species composition of the fish fillet.

In all cases, the deep-fat frying process caused a significant (P < 0.05) increase in the relative proportions of the PE and PC species constituted by the combination of palmitic and docosahexaenoic acids. At the same time, a depletion of the percentage of the PE and PC species formed by two docosahexaenoic acid residues in fried fillets was registered. Anyway, this depletion was statistically significant for PC, but not for PE.

Both PE and PC compositions were not influenced by the frying temperature, whereas the nature of the culinary fat had an effect on the PC composition. Particularly, the frying tests with conventional sunflower oil produced a statistically significant increase of PC species containing saturated/polyunsaturated fatty acids and a significant decrease of PC species formed by the combination of two polyunsaturated fatty acids.

Introduction

Fish is an excellent source of nutrients such as essential amino acids, bioactive fatty acids, minerals, vitamins, chitin and antioxidants (Gebauer, Psota, Harris, & Kris-Etherton, 2006). Extensive epidemiological studies have demonstrated the protective role of fish and fish oil consumption against a wide range of diseases that are becoming more widespread in Western populations, including coronary heart diseases (Barringer and Harris, 2012, Calder and Yaqoob, 2009, Saravanan et al., 2010), type 2 diabetes (Malekshahi et al., 2012), inflammatory disorders (Simopoulos, 2008), cancer (MacLean, Newberry, Mojica, & Khanna, 2006) and neurodegenerative diseases (Freeman et al., 2006, Huang, 2010).

The potential health and nutritional benefits of fish consumption are mainly attributed to the lipid fraction, which is primarily composed of phospholipids (PLs) and triacylglycerols (TAG) exceptionally rich in ω3 polyunsaturated fatty acids (ω3 PUFA). The strong and positive biological activities of ω3 PUFA have been confirmed by extensive research over the past several decades and various governments and health organizations are currently recommending dietary intakes for total ω3 PUFA of 1.4–2.5 g/day (Lichtenstein et al., 2006, Harris et al., 2009). Nevertheless, in many societies of the Western style diet, the daily ω3 PUFA dose requirement is not always ensured.

Despite intensive investigation devoted to the achievement of an adequate dietary intake of ω3 PUFA, more recently, attention has also been focused towards the effects of different ω3 PUFA dietary forms (i.e., ethyl esters or PLs) (Neubronner et al., 2011). Within this context, fish PLs have created a great deal of interest (Burri et al., 2012, Dasgupta and Bhattacharyya, 2007, Shirouchi et al., 2007) since they have shown to be more efficient carriers of ω3 PUFA than fish TAGs in terms of ω3 PUFA absorption in different tissues (Parmentier, Al Sayed Mahmoud, Linder, & Fanni, 2007). This is particularly true when ω3 PUFA, such as eicosapentaenoic acid (EPA, 20:5ω3), docosapentaenoic acid (DPA, 22:5ω3) and docosahexaenoic acid (DHA, 22:6ω3), are mainly esterified at the sn-2 position, as observed in marine PLs. In addition, fish PLs have also exhibited anti-inflammatory and antitumor-promoting effects.

Sardine (Sardina pilchardus) is one of the most commercialized and consumed fishes in the Mediterranean area (Ismea, 2012, pp. 2–5). Sardine lipids have important nutritional characteristics because of their particularly high level of ω3 PUFAs, thus allowing the recommended dietary intake of PUFAs to be easily reached consuming less than three serving of this kind of fish per week and without the need for any supplementation (Bandarra et al., 1997, Cardenia et al., 2013, Pacetti, Balzano, et al., 2013, Pacetti, Mozzon, et al., 2013). However, most fish are consumed cooked, and considering that the culinary processes undoubtedly alter the content, the composition and the biological activity of the fish lipids, the nutritional value of the final cooked product is of major importance for human health (Nomikos, Karantonis, Skarvelis, Demopoulos & Zabetakis, 2006). Within the wide range of available cooking procedures, deep-fat frying is one of the most common food processing methods used for preparing a worldwide variety of foods, including fish. During frying both oil and food are modified, with ω3 long chain PUFAs in PLs representing the most heat-labile and oxidation-sensitive fatty acids. Over the past 30 years, several studies were undertaken to determine the effects of deep fat-frying and pan-frying on the fatty acids of fish species (Ansorena et al., 2010, Candela et al., 1998, Gladyshev et al., 2007, Sanchez-Muniz et al., 1992, Sebedio et al., 1993, Sioen et al., 2006, Weber et al., 2008, Zervou et al., 2012; Zhang et al., 2013). However, despite the increased interest in the nutritional and biological activities of ω3 PUFA rich PLs, there are no current data regarding the modifications of PLs profile that occur during the deep fat-frying procedure. Therefore, the aim of our work was to determine the effects on PL composition of edible muscle (fillet) of S. pilchardus of deep-fat frying performed using different culinary fats (extra virgin olive oil, conventional sunflower oil and high-oleic sunflower oil) and different temperatures (160 and 180 °C). The PL molecular species of the main fish PL classes (phosphatidylethanolamine, PE, phosphatidylcholine, PC) were determined by high pressure liquid chromatography (HPLC) coupled with a second order mass spectrometer (MS–MS) with electronebulization interface (ESI).

Beyond providing new information about the effect of the frying process on the ω3 PUFA rich PLs composition, this work helps to clarify the influence of different culinary fats and frying temperatures on the evolution of the PLs fraction, thus providing consumers and food industry with additional knowledge that can be used for the control and/or the preservation of the fried fish quality.

Section snippets

Material

Chloroform and methanol were HPLC grade from Lab-Scan (Dublin, Ireland); ammonia solution (30%) of analysis grade was from Carlo Erba (Milano, Italy). All other chemicals, with noted exceptions, were obtained from Sigma Chemicals Co. (St. Louis, MO). PLs standards including 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE, purity > 99%), 1,2-dipalmitoyl-sn-glycero-3-phosphocoline (DPPC, purity > 99%), 1-palmytoil-2-oleoyl-sn-glycero-3-phosphocoline (POPC, purity > 99%), 1,2-dipalmitoyl-sn

Separation of phospholipid classes and identification of phospholipid molecular species

The HPLC/ESI-MS-MS method previously developed for the characterization of phospholipid molecular species in fish and shellfish (Boselli, Pacetti, Lucci, & Frega, 2012) was applied to the qualitative and semi-quantitative analysis of the phospholipid molecular species in raw and fried sardine fillets. In the chromatographic conditions adopted, all PL classes eluted within 14 min in the following order: plasmalogen phosphatidylethanolamine (pPE) < PE < phosphatidylinositol

Discussion

The deep-fat frying process caused significant changes on PE and PC molecular species composition. Frying led to a significant relative increase of the proportion of the PE and PC species formed by the combination of palmitic and docosahexaenoic acids and to a slight (P > 0.05) depletion of the percentage of the PE and PC species formed by two docosahexaenoic acid residues in fried fillets. The PC composition resulted to be more affected by the frying process than PE. In fact, although the

Conclusions

Nowadays consumers demand for an improved quality of foodstuffs expecting that certain processed food would exhibit nutritional quality in addition to sensorial attributes as well.

Taking into account the nutritional relevance of food phospholipids, our finding contributes with original results concerning the effects of deep-fat frying on the fish phospholipid molecular species, needed to achieve the nutritional value of the final cooked fish. Noteworthy, most fish species, especially sardine,

References (66)

  • J.L. Sebedio et al.

    Stability of polyunsaturated omega-3 fatty acids during deep fat frying of Atlantic mackerel (Scomber scombrus L.)

    Food Research International

    (1993)
  • I. Sioen et al.

    Effects of pan-frying in margarine and olive oil on the fatty acid composition of cod and salmon

    Food Chemistry

    (2006)
  • J. Weber et al.

    Effect of different cooking methods on the oxidation, proximate and fatty acid composition of silver catfish (Rhamdia quelen) fillets

    Food Chemistry

    (2008)
  • K.A. Zemski Berry et al.

    Electrospray ionization tandem mass spectrometry of glycerophosphoethanolamine plasmalogen phospholipids

    Journal of the American Society for Mass Spectrometry

    (2004)
  • Q. Zhang et al.

    Chemical alterations taken place during deep-fat frying based on certain reaction products: a review

    Chemistry and Physics of Lipids

    (2012)
  • D. Ansorena et al.

    Effect of fish and oil nature on frying process and nutritional product quality

    Journal of Food Science

    (2010)
  • M. Araseki et al.

    Oxidative stability of polyunsaturated fatty acid in phosphatidylcholine liposomes

    Bioscience, Biotechnology and Biochemistry

    (2002)
  • N.M. Bandarra et al.

    Seasonal changes in lipid composition of sardine (Sardina pilchardus)

    Journal of Food Science

    (1997)
  • T.A. Barringer et al.

    Omega-3 fatty acids and cardiovascular disease prevention

    Current Nutrition Reports

    (2012)
  • E.G. Bligh et al.

    A rapid method of total lipid extraction and purification

    Canadian Journal of Biochemistry and Physiology

    (1959)
  • M.M. Blumenthal

    A new look at the chemistry and physics of deep-fat frying

    Food Technology

    (1991)
  • E. Boselli et al.

    Characterization of phospholipid molecular species in the edible parts of bony fish and shellfish

    Journal of Agricultural and Food Chemistry

    (2012)
  • L. Burri et al.

    Marine omega-3 phospholipids: metabolism and biological activities

    International Journal of Molecular Sciences

    (2012)
  • P.C. Calder et al.

    Omega-3 polyunsaturated fatty acids and human health outcomes

    Biofactors

    (2009)
  • M. Candela et al.

    Deep-fat frying modifies high-fat fish lipid fraction

    Journal of Agricultural and Food Chemistry

    (1998)
  • E. Choe et al.

    Chemistry of deep-fat frying oils

    Journal of Food Science

    (2007)
  • S. Dasgupta et al.

    Dietary effect of eicosapentaenoic acid (EPA) containing soyphospholipid

    Journal of Oleo Science

    (2007)
  • C. Dobarganes et al.

    Interactions between fat and food during deep-frying

    European Journal Lipid Science and Technology

    (2000)
  • J.S. Elmore et al.

    Effect of the polyunsaturated fatty acid composition of beef muscle on the profile of aroma volatiles

    Journal of Agricultural and Food Chemistry

    (1999)
  • L.J. Farmer et al.

    Interaction of lipid in the Maillard reaction between cysteine and ribose: the effect of a triglyceride and three phospholipids on the volatile products

    Journal of the Science of Food and Agriculture

    (1990)
  • L.J. Farmer et al.

    Effect of cysteine and ribose on the volatile thermal degradation products of a triglyceride and three phospholipids

    Journal of the Science of Food and Agriculture

    (1992)
  • M.P. Freeman et al.

    Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry

    Journal of Clinical Psychiatry

    (2006)
  • N.G. Frega et al.

    Evoluzione compositiva dell'olio durante il processo di frittura

    La rivista di Scienza dell'Alimentazione (Journal of Food Science and Nutrition)

    (2011)
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