Oleic Acid Is not the Only Relevant Mono-Unsaturated Fatty Ester in Olive Oil

Absolute kinetics of peroxidation and antioxidant protection of intact triglyceride vegetable oils

To verfy their difference from isolated fatty acids, the absolute kinetics of peroxidation was studied for seven triglyceride-based oils of olive (OLI-1, OLI-2), high-oleic sunflower (SUN-HO), high-oleic and high-linoleic safflower (SAF-HO, SAF-HL) grapeseed (GRA) and borage (BOR), by oxygen uptake monitoring, using 2,6-di-tert-butyl-4-methoxyphenol and 2,2,5,7,8-pentamethyl-6-chromanol as reference inhibitors. Propagation constants (kp/M-1 s-1 at 303 K in PhCl) were respectively 34.8 ± 2.3, 35.1 ± 1.8, 40.6 ± 5.5, 36.0 ± 7.7, 160.8 ± 5.1, 145.1 ± 24.5, 275.1 ± 63.8, while oxidizability responded to empirical equation kp(2kt)-½/M-½s-½ = 1.63 × 10-3[allyl >CH2/M] + 1.82 × 10-2[bisallyl >CH2/M], based on fatty acids residues assessed by GC-MS. Peroxidation kinetics was markedly different from that of isolated fatty acids. The H-bond basicity of all oils was measured by FT-IR affording Abraham's βH2 values in the range 0.55 ± 0.03. H-bonding explained the protection of oils measured for seven reference phenolic antioxidants, except for the catechols quercetin and caffeic acid phenethyl ester, which were 2-to-4-folds more effective than expected, supporting a proposed different mechanism.

Cold-Pressed Pomegranate Seed Oil: Study of Punicic Acid Properties by Coupling of GC/FID and FTIR

Over the last decades, we have witnessed an increasing interest in food-related products containing vegetable oils. These oils can be obtained either by extraction or by mechanical pressing of different parts of plants (e.g., seeds, fruit, and drupels). Producers of nutraceuticals have ceaselessly searched for unique and effective natural ingredients. The enormous success of argan oil has been followed by discoveries of other interesting vegetable oils (e.g., pomegranate oil) containing several bioactives. This work describes the pomegranate fruit extract and seed oil as a rich source of conjugated linolenic acid as a metabolite of punicic acid (PA), deriving from the omega-5 family (ω-5). Through the chemical characterization of PA, its nutritional and therapeutic properties are highlighted together with the physiological properties that encourage its use in human nutrition. We analyzed the composition of all fatty acids with beneficial properties occurring in pomegranate seed oil using gas chromatography (GC) with flame-ionization detection (FID) analysis combined with Fourier transform infrared spectroscopy (FTIR). Pomegranate seed oil mainly consists of 9,11,13-octadic-trienoic acid (18:3), corresponding to 73 wt % of the total fatty acids. Nine components were identified by GC in PSO, varying between 0.58 and 73.19 wt %. Using midinfrared (MIR) spectroscopy, we compared the composition of pomegranate seed oil with that of meadowfoam seed oil (MSO), which is also becoming increasingly popular in the food industry due to its high content of long chain fatty acids (C20-22), providing increased oil stability. From the results of FTIR and MIR spectroscopy, we found that punicic acid is unique in PSO (73.19 wt %) but not in MSO.

Exploring Lignans, a Class of Health Promoting Compounds, in a Variety of Edible Oils from Brazil

Lignans, a group of polyphenols, have been identified in eight cold pressed oils from fruits, nuts, and seeds, retrieved from the Brazilian market. The oils under investigation were avocado, Brazilian nut, canola, coconut, grapeseed, macadamia, palm, and pequi. Olive oil was selected as a reference oil, since numerous data on its lignan content are available in literature. The qualitative and quantitative profiles were obtained, after extraction, by means of UFLC-ESI-MS/MS analyses. The total lignan content showed a high variability, ranging from 0.69 mg·Kg-1 (pequi) to 7.12 mg·Kg-1 (grapeseed), with the highest content registered for olive oil. Seven lignans were quantified, matairesinol and pinoresinol being the most abundant. The LC-MS/MS method was validated, showing linearity in the range of 12.5-212.5 mg·Kg-1, LOD in the range of 0.18-11.37 mg·Kg-1, and LOQ in the range of 0.53-34.45 mg·Kg-1. Additionally, part of the study was focused on the evaluation of the flavor profile, this being a key element in consumers' evaluations, by means of HS-SPME-GC. In total, 150 volatile compounds were determined in the eight oils, with identified fractions ranging from 91.85% (avocado) to 96.31% (canola), with an average value of 94.1%. Groups of components contributed characteristically to the flavour of each oil.

Deep-frying purple potato Purple Majesty using sunflower oil: effect on the polyphenols, anthocyanins and antioxidant activity

The potato is a root vegetable native to the Americas; it consists of the starchy tuber of the plant Solanum tuberosum. There are many varieties, and the flesh can have different colour ranging from yellow to red and purple. Coloured varieties have a denser texture and slightly nuttier, earthier flavour than other potatoes. The desirable quality characteristics of potatoes depends on the intended use, and the acceptability of raw potatoes is determined by size, shape, colour, and the quality of can be evaluated in terms of colour, flavour, and texture. Deep-frying is the century-old and it is among the most common cooking processes, still being used to prepare a variety of food products on both industrial and domestic scales. Frying the potatoes is among the tastiest and appreciated way to cook this vegetable. Purple fleshed potatoes are widely considered one of the best-tasting purple potatoes varieties, they have a nice taste and add colour to a meal. They are a source of beneficial health compounds which makes them interesting as functional food. The anthocyanins present in the Purple Majesty variety are interesting for their health promoting abilities, anti-oxidative activity, and even other health beneficial effects, e.g. anti-influenza virus activity, and anti-stomach cancer activity. The aim of this study has been to assess the effect of deep-frying of purple potato Purple Majesty using sunflower oil on the polyphenols, anthocyanins and to evaluate the antioxidant activity of the cooked matrix compared to the fresh one. The results seem to suggest that the healthy characteristics of this functional food are retained after the cooking by frying.

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Purple potato “Purple Majesty” is rich in antioxidants and anthocyanins.

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Deep frying in sunflower oil affects positively the antioxidant activity.

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The anthocyanins increase their amount in the frying time range.

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Polyphenols amount decreases during frying time.

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The ferulic and gallic acids seem to increase their amount after 48 h of frying.

Cardoon (Cynara cardunculus L. var. altilis) seeds presscake: a natural by-product for pigs feeding

The cardoon seeds presscake is a natural by-product resulting from the mechanical treatment of the cardoon plant seeds. The chemical composition suggests its possible use in animal nutrition due to the content of proteins, fibre, lipids and biologically active substances. The presscake studied contained 7.1% of fat, 26.8% of fibre, 23.9% of protein, 37.1% of nitrogen-free extract and a goodly phenolic content (13.36 mg GAE g^-1 DW). The major fatty acids were oleic (26.5%) and linoleic (58.4%), showing a high degree of unsaturation. This study evaluated for the first time the inclusion of the cardoon presscake in pigs' diet. The effects of the dietary treatment on meat quality and fatty acids profile were assessed. The results indicate that the intramuscular fat (IMF) was higher in the untreated animals. The monounsaturated fatty acids (MUFAs) were lower in the IMF of the treated pigs, whereas the polyunsaturated fatty acids (PUFAs) were higher.

Composition Profiling and Authenticity Assessment of Camellia Oil Using High Field and Low Field 1H NMR

Camellia oil (CA), mainly produced in southern China, has always been called Oriental olive oil (OL) due to its similar physicochemical properties to OL. The high nutritional value and high selling price of CA make mixing it with other low-quality oils prevalent, in order to make huge profits. In this paper, the transverse relaxation time (T₂) distribution of different brands of CA and OL, and the variation in transverse relaxation parameters when adulterated with corn oil (CO), were assessed via low field nuclear magnetic resonance (LF-NMR) imagery. The nutritional compositions of CA and OL and their quality indices were obtained via high field NMR (HF-NMR) spectroscopy. The results show that the fatty acid evaluation indices values, including for squalene, oleic acid, linolenic acid and iodine, were higher in CA than in OL, indicating the nutritional value of CA. The adulterated CA with a content of CO more than 20% can be correctly identified by principal component analysis or partial least squares discriminant analysis, and the blended oils could be successfully classified by orthogonal partial least squares discriminant analysis, with an accuracy of 100% when the adulteration ratio was above 30%. These results indicate the practicability of LF-NMR in the rapid screening of food authenticity.

Chemical analysis, biological and therapeutic activities of Olea europaea L. extracts

The Olea europaea L. is a very well-known and widely used plant, especially for its nutritional qualities. Its extracts from leaves and fruits are widely used in contrasting and preventing various pathologies. In this review, the collected data highlight important chemical analyses and biological effects of this plant extracts. It exhibits cholesterol-lowering, hypoglycemic, cytotoxic, antibacterial, neuroprotective, antioxidant, anti-inflammatory and hypotensive activities. The results show that extracts from O. europaea could be used as a food additive in the supplementary treatment of many diseases.

Oxidative stability of high oleic sunflower oil during deep-frying process of purple potato Purple Majesty

The behaviour of high oleic sunflower oil in deep frying process of purple potato Purple Majesty has been evaluated simulating a fast food cooking process. This oil was used for 8h/day for 6 days, filling up from the 2nd day. A discontinuous and prolonged procedure was tested. Free Fatty Acidity (FFA), Peroxide Value (PV), Total Polar Compounds (TPC), Fatty Acid (FA) composition, Volatile Organic Compounds (VOC) have been determined at different times in thermo-oxidized (T-OX) oil, and in frying oil. The FFA in T-OX oil samples showed values in the range 0.09%–0.24%, whereas in the frying oil values varied in a range between 0.09% and 0.16%. TPCs values varied from 1.76% to 38.24% in T-OX oils, whereas in frying oil used for frying purple potatoes (FOPP) showed values in the range from 1.76 to 29.13%. The peroxides values did not follow a regular pattern, both during thermo-oxidation and during frying. Among the Long Chain Fatty Acids (LCFAs), oleic acid was the most represented (84.13%). Short chain fatty acids (SCFAs) amount was 0.34% (octanoic acid). Medium chain fatty acids (MCFA) amount was 4.45% (palmitic acid). During the thermo-oxidation, the poly-unsaturated fatty acids (PUFA) amount decreased during the 48 h of heat treatment, reaching an amount of 6.21%. This determined the increase in short chain fatty acids (SCFA). Trans fatty acids increased with the frying time. Unsaturated fatty acids (UFA) reached the value of 90.19%; SFA was 9.79%, and octanoic acid was 0.20%. A correlation between TPC vs UFA/SFA and TPC vs C18:2/C16:0 was observed in the frying oil. The most abundant volatile compounds in frying oil (from 0 to 48 h) were the aldehydes produced by decomposition of hydroperoxides of oleic and linoleic acids.

Olive Oil Quality and Authenticity Assessment Aspects Employing FIA-MRMS and LC-Orbitrap MS Metabolomic Approaches

Edible vegetable oils comprise integral components of humans' daily diet during the lifetime. Therefore, they constitute a central part of dietary-exposome, which among other factors regulates human health. In particular, the regular consumption of olive oil (OO) has been largely accepted as a healthy dietary pattern. Responsible for its recognition as a superior edible oil is its exceptional aroma and flavor. Its unique composition is characterized by high levels of monounsaturated fatty acids and the presence of minor constituents with important biological properties, such as the so-called OO polyphenols. Being a high added value product, OO suffers from extensive fraud and adulteration phenomena. However, its great chemical complexity, variability, and the plethora of parameters affecting OO composition hamper significantly the selection of the absolute criteria defining quality and authenticity, and a reliable and robust methodology is still unavailable. In the current study, Flow Injection Analysis-Magnetic Resonance Mass Spectrometry (FIA-MRMS) was investigated under a metabolic profiling concept for the analysis of Greek Extra Virgin Olive Oils (EVOO). More than 200 monovarietal (Koroneiki) EVOO samples were collected from the main Greek OO producing regions and investigated. Both intact oil and the corresponding polyphenols were analyzed in fast analysis time of 2 and 8 min, respectively. In parallel, an LC-Orbitrap MS platform was used to verify the efficiency of the method as well as a tool to increase the identification confidence of the proposed markers. Based on the results, with FIA-MRMS, comparable and improved projection and prediction models were generated in comparison to those of the more established LC-MS methodology. With FIA-MRMS more statistically significant compounds and chemical classes were identified as quality and authenticity markers, associated with specific parameters, i.e. geographical region, cultivation practice, and production procedure. Furthermore, it was possible to monitor both lipophilic and hydrophilic compounds with a single analysis. To our knowledge, this approach is among the few studies in which two FT-MS platforms combining LC and FIA methods were integrated to provide solutions to quality control aspects of OO. Moreover, both lipophilic and hydrophilic components are analyzed together, providing a holistic quality control workflow for OO.

Theoretical prediction of 13C NMR spectrum of mixed triglycerides by mean of GIAO calculations to improve vegetable oils analysis

This pioneering study based on GIAO-DFT methods is aimed to the best prediction of ¹³C Nuclear Magnetic Resonances (NMR) arising from triglycerides (and also glycerols), known to be the main component of vegetable oils. Provided that fatty esters bound to the glycerol moiety are not affected by the other esterification chains, and slightly affected by their own esterification position (2- internal, or 1/3- external), eight natural molecules are first optimized despite the challenging presence of many non-hydrogen atoms and the large conformational freedom. This preliminary study sheds light on the total chemical shift prediction concerning five fatty esters (Oleic, Palmitic, Linoleic, Stearic and Linolenic) either present in internal or external positions (ten fragments in total); these results display a very good matching to the experimental profile recorded for several vegetable oils chosen as natural mixtures of glycerides. In order to further improve the theoretical to experimental matching, ten simplified triglycerides with the mentioned fatty esters in the two different esterification positions, and flanked by acetyl esters, were studied and optimized. Beyond the best matching reached so far, we notice that the theoretical rationalisation of the overcrowding in the 28.7-29 ppm spectral region in unable to decode the necessary resolution, nonetheless the same theoretical prediction can still drive the appropriate assignments (as for the fifth and sixth carbon attribution of every chain) even against actual misleading reports.

Development of Food Chemistry, Natural Products, and Nutrition Research: Targeting New Frontiers

The Special Issue entitled: "Development of Food Chemistry, Natural Products, and Nutrition Research" is focused on the recent development of food chemistry research, including natural products' sources and nutrition research, with the objectives of triggering interest towards new perspectives related to foods and opening a novel horizon for research in the food area. The published papers collected in this Special Issue are studies that refer to different aspects of food, ranging from food chemistry and analytical aspects, to composition, natural products, and nutrition, all examined from different perspectives and points of view. Overall, this Special Issue gives a current picture of the main topics of interest in the research and proposes studies and analyses that may prompt and address the efforts of research in the food area to find novel foods and novel applications and stimulate an environmentally-friendly approach for the re-use of the by-products of the agro-food area. This notwithstanding, the main challenge is currently addressed to achieve a full comprehension of the mechanisms of action of food components, the nutrients, outlining their high potential impact as preventive and/or therapeutic tools, not only as a source of macro- and/or micro-nutrients, which are necessary for all the metabolic and body functions.