Cyclic Fatty Acids in Food: An Under-Investigated Class of Fatty Acids

Cyclic fatty acids are an unusual class of minor fatty acids generally produced by bacteria and less frequently by plants. Among plants, the most known cyclic fatty acid is sterculic acid (9, 10-methyleneoctadecenoic acid) produced by Sterculia foetida. Bacteria (e.g., lactic acid bacteria) synthetize cyclopropane fatty acids, such as dihydrosterculic acid (9, 10-methylene octadecanoic acid) and lactobacillic acid (11, 12 methylene octadecanoic acid), to strength their membrane, improving their resistance to environmental stress. Another class of cyclic fatty acids is omega-cyclohexyl fatty acids, present in milk and probably produced by rumen bacteria. Cyclopropane and omega-cyclohexyl fatty acids have been recently found in bovine meat and dairy products, representing important foodstuffs in human diet. In this chapter, a review of literature data concerning the presence of cyclic fatty acids in foods, their metabolism in humans, and their potential bioactivity will be provided. The role of some cyclic fatty acids as molecular markers for food authenticity will also be highlighted

Influence of the killing method of the black soldier fly on its lipid composition

Black soldier fly (BSF, Hermetia illucens) represents a valuable source of biomolecules and it also constitutes an economic way to valorise residual biomasses. BSF prepupae contain high amounts of lipids (37% DM basis). The present investigation aimed at studying the composition of BSF lipids and the effect of killing/storage on their quality. The main fatty acid was lauric acid, sterols were represented primarily by beta-sitosterol and campesterol. Global fatty acid and sterol profiles, determined by GC–MS, were only slightly affected by the killing procedure, while lipid classes distribution, determined by 1H NMR, strongly changed. Prepupae killed by freezing showed a drastic reduction of acylglycerols during storage and a relevant release of free fatty acids, likely due to activation of lipases. On the contrary, prepupae killed by blanching have a stable lipid fraction constituted mainly by triacylglycerols. Therefore, killing procedure strongly influences BSF oil composition and the potential applications

An Overview on Cyclic Fatty Acids as Biomarkers of Quality and Authenticity in the Meat Sector

peer-reviewedA survey was conducted to determine the content of cyclopropane fatty acids (CPFAs) and ω-cyclohexyl fatty acids (CHFAs) by using gas chromatography- mass spectrometry (GC-MS) and proton nuclear magnetic resonance (1H NMR) techniques in various meat samples from different species, including commercial samples and complex and thermally processed products (i.e., Bolognese sauce). The CPFAs concentration (as the sum of two isomers, namely dihydrosterculic acid and lactobacillic acid) in bovine meat fat (ranging between 70 and 465 mg/kg fat) was positively related to a silage-based diet, and therefore, they are potential biomarkers for monitoring the feeding system of cattle. CHFAs, such as 11-cyclohexylundecanoic and 13-cyclohexyltridecanoic acids, were only found in lipid profiles from ruminant species, and a linear trend was observed in their content, together with iso-branched fatty acids (iso-BCFAs) deriving from ruminal fermentation, as a function of bovine meat percentage in both raw and cooked minced meat. Thus, CHFAs are potential biomarkers for the assurance of the meat species and, combined with iso-BCFAs, of the beef/pork ratio even in complex meat matrices. The proposed approaches are valuable novel tools for meat authentication, which is pivotal in the management of meat quality, safety, and traceability

Gamma-Ray Burst observations by the high-energy charged particle detector on board the CSES-01 satellite between 2019 and 2021

In this paper we report the detection of five strong Gamma-Ray Bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite (CSES-01), operational since 2018 on a Sun-synchronous polar orbit at a $\sim$ 507 km altitude and 97$^\circ$ inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3 - 100 MeV, protons in the range 30 - 300 MeV, and light nuclei in the range 30 - 300 MeV/n. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV - 50 MeV, even if with a moderate effective area above $\sim$ 5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterised by a fluence above $\sim$ 3 $\times$ 10$^{-5}$ erg cm$^{-2}$ in the energy interval 300 keV - 50 MeV, have been detected.Comment: Accepted for publication in The Astrophysical Journal (ApJ

Cyclic fatty acids in foods: origin, role in food authentication, relevance in the human diet, and health aspects

Cyclic fatty acids are an unusual class of minor fatty acids generally produced by bacteria and less frequently by plants. Bacteria (e.g. lactic acid bacteria) synthetize cyclopropane fatty acids, as dihycrosterculic acid (9, 10-methylene octadecanoic acid) and lactobacillic acid (11, 12 methylene octadecanoic acid), to strength their membrane, improving their resistance to environmental stress. Another class of cyclic fatty acids is omega-cyclohexyl fatty acids, present in milk and probably produced by rumen bacteria. Cyclopropane and omega-cyclohexyl fatty acids have been recently found in bovine meat and dairy products, representing important foodstuffs in human diet. The doctoral research project principally focused on the application of GC-MS and 1H NMR techniques to study cyclic fatty acids as molecular markers for food authenticity and their role in human nutrition. The occurrence and content of cyclopropane fatty acids in dairy and meat products were mainly correlated with the feeding system (use of silages in ration), whereas omega-cyclohexyl fatty acids have been proposed as markers for ruminant species. From a nutritional point of view, the origin and the presence of cyclic fatty acids (especially cyclopropane fatty acids) in several food sources, their bioavailability and potential bioactivity in humans have been investigated. Data presented in this PhD thesis represent a promising starting point for future studies on their potential healthy aspects

Preliminary evaluation of 3-keto-4-cholestene in Parmigiano Reggiano P.D.O. cheese

The maximum percentage of cheese rind in Parmigiano Reggiano P.D.O. grated cheese is fixed at 18% by the product Specification. Purpose of the present study is to evaluate the presence of 3-keto-4-cholestene in grated Parmigiano Reggiano cheese and rind in different ages (12 and 24 months) and from different cleaning treatments of the rind (washing by water and dry scraping of the rind). The study analysed 31 samples of cheese rind and 10 samples of cheese by GC-MS, detecting the ratio between the area of 3-keto-4-cholestene and cholesterol. Preliminary data suggested that the absence of this molecule in the samples from the inner part of the wheel and its presence in the samples from the rind could be used to discriminate these two kinds of samples. Regarding other variables (ages and cleaning treatment), due to low number of samples and high degree of variability among samples from the same group, it is not possible to define a significative correlation and further studies are needed

Development of a Quantitative GC-MS Method for the Detection of Cyclopropane Fatty Acids in Cheese as New Molecular Markers for Parmigiano Reggiano Authentication

Cyclopropane fatty acids (CPFA), as lactobacillic acid and dihydrosterculic acid, are components of bacterial membranes and have been recently detected in milk and in dairy products from cows fed with corn silage. In this paper, a specific quantitative gas chromatography-mass spectrometry (GC-MS) method for the detection of CPFA in cheeses was developed, and the quality parameters of the method (limit of detection, limit of quantitation, and intralaboratory precision) were assessed. Limit of detection and quantitation of CPFA were, respectively, 60 and 200 mg/kg of cheese fat, and the intralaboratory precision, determined on three concentration levels, satisfied the Horwitz equation. This method was applied to 304 samples of PDO cheeses of certified origin, including Parmigiano Reggiano (Italy), Grana Padano (Italy), Fontina (Italy), Comté (France), and Gruyère (Switzerland). Results showed that CPFA were absent in all of the cheeses whose Production Specification Rules expressly forbid the use of silages (Parmigiano Reggiano, Fontina, Comté, and Gruyère). CPFA were instead present in variable concentrations (300-830 mg/kg of fat) in all of the samples of Grana Padano cheese (silages admitted). A mix of grated Parmigiano Reggiano and Grana Padano was also prepared, showing that the method is able to detect the counterfeiting of Parmigiano Reggiano with other cheeses up to 10-20% Grana Padano content. These results support the hypothesis that CPFA can be used as a marker of silage feedings for cheeses, and the data reported can be considered a first attempt to create a database for CPFA presence in PDO cheeses