Identification and Quantification of Fatty Acids in T. viridissima, C. biguttulus, and C. brunneus by GC-MS

Hindawi Journal of Lipids Volume 2018, Article ID 3679247, 8 pages https://doi.org/10.1155/2018/3679247 Research Article Identification and Quantification of Fatty Acids in T. viridissima, C. biguttulus, and C. brunneus by GC-MS Alexander M. Wathne , Hanne Devle , Carl Fredrik Naess-Andresen, and Dag Ekeberg Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway Correspondence should be addressed to Alexander M. Wathne; Received 27 July 2017; Revised 12 January 2018; Accepted 4 February 2018; Published 28 February 2018 Academic Editor: Maurizio Averna Copyright © 2018 Alexander M. Wathne et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Fatty acid (FA) profiles of the species Tettigonia viridissima, Chorthippus biguttulus, and Chorthippus brunneus were determined and quantitated. Extracted lipids were derivatized into FA methyl esters (FAMEs) prior to analysis by GC-MS. A total of 37 different FAs were identified in T. viridissima, yielding a total FA content of 10.4 g/100 g of dry matter. The contents of saturated FAs, monounsaturated FAs, and polyunsaturated FAs were 31.1, 35.9, and 33.0%, respectively. Lipids from T. viridissima were also fractioned into neutral lipids, free fatty acids, and polar lipids by offline solid phase extraction. For C. brunneus and C. biguttulus, 33 FAs were identified, yielding a total FA content of 6.14 g/100 g of dry matter. SFAs, MUFAs, and PUFAs, respectively, constituted 32.7, 25.1, and 42.1% of the total FA content. The contents of MUFAs, PUFAs, n-3 FAs, and n-6 FAs of each species, and the n-6/n-3 ratio, were subsequently discussed. 1. Introduction As the world’s population surges towards a total of 9 billion people by the middle of the 21st century, an increased global demand for food will inevitably follow. Additionally, a higher consumption of beef, fish, and poultry will be facilitated by the higher purchasing power of the emerging middle class in developing countries, resulting in an increased pressure on the food supply system [1]. An estimated 800 million people still experience hunger around the globe, chronically or transitionally [2]. To face the daunting task of feeding the growing population and those currently lacking basic nutrition, novel and more efficient foods will have to be studied and consequently utilized for human consumption on an industrial scale. Insects play an important role in human nutrition outside Europe in areas such Asia, Africa, and South-America, functioning as a nutritionally viable alternative to meats and fish [3]. Moreover, insects also provide important micronutrients such as calcium, iron, and zinc [4]. Approximately 13% of the insects consumed globally belong to the order Orthoptera, which includes grasshoppers, crickets, and locusts [4]. Essential fatty acids (EFAs) are defined as FAs essential to growth and development [5]. These EFAs must be supplied through the diet, as they are not synthesized by the human body. Linoleic acid (LA) and 𝛼-linolenic acid (ALA), an n-6 and n-3 FA, respectively, have been identified as the two EFAs required to be included in the diet [6]. Both are precursors to the n-6 FA arachidonic acid (AA), but only ALA acts as a precursor to the important n-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are produced through biosynthesis by elongation and desaturation [7]. DHA and EPA have been associated with proper retinal and immune function and are present in significant quantities in both the brain and the nervous system [8– 10]. Deficiencies of EPA and DHA have been linked to several chronic diseases and disorders [11, 12]. Furthermore, low levels of dietary ALA have been associated with overall deficiencies of both DHA and EPA [13]. The intake ratio of n-6 to n-3 FAs through diet has also been reported to be of significance in overall health [14–17], with ratios ranging from 1/1 to 2/1 being highlighted as optimal. Western societies in particular have a high intake of n-6 FAs compared to n-3 FAs [18]. A high intake of n-6 FAs results 2 in increased levels of proinflammatory, prothrombotic, and proaggregatory eicosanoid secondary metabolites at the expense of anti-inflammatory and hypolipidemic eicosanoids derived from n-3 FAs [5, 19]. However, it should be noted that the FAO does not give any specific recommendations for this ratio and that the importance of this ratio is debated [6]. In studies evaluating insects as a part of human diet one should consider the crucial role of FAs, and in particular the influence of EFAs on human health. The FA composition will vary with individual species, their development phase, diet, and environmental factors [20]. However, few efforts have been made to explore the composition of fats in grasshoppers [20]. The study of Paul et al. [21] elucidated the FA contents of three Orthopterans, Acheta domesticus (Gryllidae family), Conocephalus discolor (Tettigoniidae family), and Chorthippus parallelus (Acrididae family), by utilizing GC-FID. Their results revealed high concentrations of LA and ALA, as well as oleic acid. Yang et al. [22] studied the FA profiles of three Orthopterans (Gryllidae and Acrididae family) native to Thailand, also revealing significant concentrations of these FAs. Additionally, in their study the spur-throated grasshopper, Chondracris roseapbrunner (Acrididae family), displayed a favourable n-6/n-3 ratio of 0.3/1. Fractioning of FAs from insects by use of offline solid phase extraction (SPE) appears to be lacking in the literature. Grapes et al. [23] fractionated the lipids extracted from organs in adult females belonging to Acheta domesticus into three classes: neutral lipids (NLs), polar lipids (PLs), and free fatty acids (FFAs). In their study, diacylglycerides and triacylglycerides from the NL fraction were found to be present in major concentrations. The objectives of this study were to identify and quantitate FAs present in the grasshopper species Chorthippus brunneus and Chorthippus biguttulus (both from the Acrididae family, Chorthippus genus), as well as the bush cricket Tettigonia viridissima (Tettigoniidae family). C. brunneus and C. biguttulus were treated as a single species (Chorthippus sp.), as they are morphologically undistinguishable [24, 25]. All three species belong to the order Orthoptera and are commonly found in southern Scandinavia, continental Europe, temperate Asia, and parts of northern Africa. To evaluate the potential health benefits by incorporating these insects into the diet, saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), n-3, and n-6 FAs were the focus of the study, as well as the n-6/n-3 ratio. To the knowledge of the authors, the work pre (...truncated)