Valuable furan fatty acids in soybeans and soy products

Abstract

Furan fatty acids (FuFAs) are valuable minor fatty acids, characterized by a central furan ring within the acyl chain. This furan moiety can be substituted with one (monomethyl, M-FuFAs) or two methyl groups (dimethyl, D-FuFAs). The carboxyalkyl chain is usually odd-numbered (7 to 13 carbon atoms) while the terminal alkyl residue is typically a propyl or a pentyl group [1]. FuFAs short terms such as 9M5 (Figure 1) and 11D5 are derived from (i) a number for the carbon number of the carboxyalkyl chain (here 9 or 11), (ii) a letter for the furan moiety (M or D) and (iii) a number of carbons of the alkyl residue (here: 5 for pentyl) [2].

Furan Fatty Acids in Some 20 Fungi Species: Unique Profiles and Quantities

“…Free 8F6 (purity 95%) was ordered from Santa Cruz Biotechnology (Dallas, TX, USA) and converted into its ethyl ester (EE) according to the method of Wendlinger and Vetter . 9M5 (purity >98%; determined using GC/MS) was extracted from powder-free disposable latex gloves (VWR, Darmstadt, Germany) according to Müller et al, followed by ethylation and purification according to Müller et al 11D5-EE (purity >99%; determined using GC/MS) was isolated from a fish oil fraction . Similarly, a semiquantitative mixture of 13% 9D5-ME and 86% 11D3-ME (purity >98%; determined using GC/MS), gained from an enriched fish oil fraction, , was transesterified and purified according to Müller et al A mixture consisting of 3.2 μg/mL 8F6-EE, 2.8 μg/mL 9M5-EE, and 3.1 μg/mL 11D5-EE was prepared and used as the internal standard solution (ISTD mix).…”

“…9M5 (purity >98%; determined using GC/MS) was extracted from powder-free disposable latex gloves (VWR, Darmstadt, Germany) according to Müller et al, followed by ethylation and purification according to Müller et al 11D5-EE (purity >99%; determined using GC/MS) was isolated from a fish oil fraction . Similarly, a semiquantitative mixture of 13% 9D5-ME and 86% 11D3-ME (purity >98%; determined using GC/MS), gained from an enriched fish oil fraction, , was transesterified and purified according to Müller et al A mixture consisting of 3.2 μg/mL 8F6-EE, 2.8 μg/mL 9M5-EE, and 3.1 μg/mL 11D5-EE was prepared and used as the internal standard solution (ISTD mix). Undecanoic acid (11:0; purity >97%) and myristic acid (14:0; purity >98%), both purchased from Fluka (Steinheim, Germany), were ethylated according Müller et al 11:0-EE (0.1 mg/mL) was used as ISTD II in FuFA-ME analysis, while 14:0-EE was used as the ISTD for GC/MS analysis of CPC and CCC fractions, respectively (Supporting Information, Sections S3 and S4).…”

“…Two milliliters of the ASE extract (∼50–85 mg lipid) was transferred into a 20 mL amber glass tube, evaporated to dryness (38 °C, N 2 ), and fatty acids were converted into FAMEs according to the method of Müller et al with slight changes. In brief, 1% sulfuric acid in methanol was added, the headspace was flooded with N 2 , and the sample was heated for 2 h at 80 °C.…”

“… , β-/β′-positions of the furan moiety can either bear (i) methyl groups in both positions (family of dimethylated FuFAs; D-FuFAs), (ii) one methyl group in the β-position (family of methyl substituted FuFAs, M-FuFAs), or (iii) no methyl group (family of N-FuFAs) (Figure ). , While D-FuFAs and M-FuFAs are natural products, , N-FuFAs are low abundant secondary oxidation products of unsaturated fatty acids. , …”

“…D-/M-FuFAs are biosynthesized by plants and bacteria, while humans and animals accumulate them from food and feed. ,, In bacteria, 9M5 and 9D5 were formed from (Z)-octadec-11-enoic acid (vaccenic acid), while linoleic acid has been suggested to be the precursor of FuFAs in plants . With a few exceptions, food from animals (e.g., fish, 30–900 mg/100 g fat and butter, 1.6–48 mg/100 g fat) ,, is richer in D-/M-FuFAs than most plant-derived samples [e.g., soy 14–65 mg/100 g fatty acid methyl esters (FAMEs), fresh spinach 0.07–6.6 mg/100 g fresh weight (FW), and herbs 0.2–2.2 mg/100 g FW]. ,− …”