Fabiola Dionisi

Assessment of olive oil adulteration by reversed-phase high-performance liquid chromatography/amperometric detection of tocopherols and tocotrienols

A method involving reversed-phase high-performance liquid chromatography with amperometric detection has been developed for the analysis of tocopherols and tocotrienols in vegetable oils. The sample preparation avoids saponification. Recoveries of α-tocotrienol and γ-tocotrienol in extra virgin olive oil were 97.0 and 102.0%, respectively. No tocotrienols were detected in olive, hazelnut, sunflower, and soybean oils, whether virgin or refined. However, relatively high levels of tocotrienols were found in palm and grapeseed oils. This method could detect small quantities (1–2%) of palm and grapeseed oils in olive oil or in any tocotrienol-free vegetable oil and might, therefore, help assess authenticity of vegetable oils.

Measurement of caffeic and ferulic acid equivalents in plasma after coffee consumption: small intestine and colon are key sites for coffee metabolism.

Previous studies on coffee examined absorption of phenolic acids (PA) in the small intestine, but not the contribution of the colon to absorption. Nine healthy volunteers ingested instant soluble coffee ( approximately 335 mg total chlorogenic acids (CGAs)) in water. Blood samples were taken over 12 h, and at 24 h to assess return to baseline. Many previous studies, which used glucuronidase and sulfatase, measured only PA and did not rigorously assess CGAs. To improve this, plasma samples were analyzed after full hydrolysis by chlorogenate esterase, glucuronidase and sulfatase to release aglycone equivalents of PA followed by liquid-liquid extraction and ESI-LC-ESI-MS/MS detection. Ferulic, caffeic and isoferulic acid equivalents appeared rapidly in plasma, peaking at 1-2 h. Dihydrocaffeic and dihydroferulic acids appeared in plasma 6-8 h after ingestion (T(max=)8-12 h). Substantial variability in maximum plasma concentration and T(max) was also observed between individuals. This study confirms that the small intestine is a significant site for absorption of PA, but shows for the first time that the colon/microflora play the major role in absorption and metabolism of CGAs and PA from coffee.

Biological Functions and Metabolism of Oleoylethanolamide

The present review is focused on the metabolism and the emerging roles of oleoylethanolamide (OEA) with emphasis on its effects on food intake control and lipid metabolism. The biological mechanism of action, including a non-genomic effect mediated through peroxisome proliferator-activated receptor alpha (PPAR-α) and transient receptor potential vanilloid type 1 (TRPV1) receptor, is discussed. The research related to fatty acid ethanolamides has been focused until recently on anandamide and its interaction with cannabinoid receptor subtype 1. The roles of other N-acyl ethanolamine fatty acid derivatives have been neglected until it was demonstrated that OEA can modulate food intake control through interaction with PPAR-α. Further investigations demonstrated that OEA modulates lipid and glucose metabolism, and recent study confirmed that OEA is an antagonist of TRVP1. It has been demonstrated that OEA has beneficial effects on health by inducing food intake control, lipid β-oxidation, body weight loss and analgesic effects. The investigation of the mechanism of action revealed that OEA activates PPAR-α and stimulates the vagal nerve through the capsaicin receptor TRPV1. Pre-clinical studies showed that OEA remains active when administered orally.

AUTHENTICITY ASSESSMENT OF FATS AND OILS

Authenticity is an important issue for the food industry due to legal compliance, economic reasons (right goods for the right price), guarantee of a constant well-defined quality, use of safe ingredients (no hazardous substitutes), and religious reasons (halal, kosher). This report gives an extensive overview on the authenticity assessment of oils and fats for food products and summarizes the principal techniques useful for this assessment. Scope and limits of different analytical tools are discussed.

Stability of cyclopropane and conjugated linoleic acids during fatty acid quantification in lactic acid bacteria

Seven methods commonly used for fatty acid analysis of microgrganisms and foods were compared to establish the best for the analysis of lyophilized lactic acid bacteria. One of these methods involves fat extraction followed by methylation of fatty acids, while the other methods use a direct methylation of the samples, under different operating conditions (e.g., reaction temperature and time, reagents, and pH). Fatty acid methyl esters were identified by gas chromatography-mass spectrometry and quantified by on-column capillary gas chromatography. Two reliable methods for the analysis of fatty acids in bacteria were selected and further improved. They guarantee high recovery of classes of fragile fatty acids, such as cyclopropane and conjugated acids, and a high degree of methylation for all types of fatty acid esters. These two direct methylation methods have already been successfully applied to the analysis of fatty acids in foods. They represent a rapid and highly reliable alternative to classical time-and solvent-consuming methods and they give the fatty acid profile and the amount of each fatty acid. Using these methods, conjugated linoleic acids were identified and quantified in lactic acid bacteria.

Identification of the botanical origin of pine nuts found in food products by gas-liquid chromatography analysis of fatty acid profile.

Pine nuts are traditionally used in various part of the world for the preparation of desserts or sauces or in salads. Local production is not sufficient to cope with the high demand of pine nuts around the world, and countries such as China or Pakistan are exporting much of their production to Western countries. Almost all the nuts that are traditionally consumed belong to the Pinus genus, but over the past years, the number of consumer complaints following consumption of commercial pine nuts increased. Some consumers experienced taste disturbance lasting for up to two weeks after consumption. Food safety agencies raised some concerns regarding pine nuts imported from Asia and their association with taste disturbance. However, even though a formal association has not been found to date, the Pinus genus comprises species that are not classified as edible and could be eventually used to adulterate edible species. Pinus spp. seed lipids are known to contain very specific polyunsaturated fatty acids know as Delta5-olefinic acids. Seed fatty acid profile of conifers had been used in the past as a taxonomic marker, and in the present study to identify the botanical origin of pine nut in nine commercial products. Fast gas-liquid chromatography (GLC) was used to resolve the complete fatty acid profile of Pinus spp. samples in less than 5 min. A diagnostic index based on the relative levels of the main fatty acids including distinctive Delta5-olefinic acids was used to identify botanical origins. Results revealed the occurrence of the following Pinus spp. in commercial products: P. pinea, P. koraiensis, P. gerardiana, P. armandii and P. massoniana. The later two species, known as Chinese white pine and Chinese red pine, are only cultivated in China and are not listed as common source of edible pine nuts by the Food and Agriculture Organization (FAO). The present study shows that the botanical origin of pine nuts can be identified in products based on the fatty acid profile.

Nondairy Creamer, but Not Milk, Delays the Appearance of Coffee Phenolic Acid Equivalents in Human Plasma

Chlorogenic acids (CGA) are antioxidants found in coffee. They are becoming of interest for their health-promoting effects, but bioavailability in humans is not well understood. We hypothesized that adding whole milk or sugar and nondairy creamer to instant coffee might modulate the bioavailability of coffee phenolics. Nine healthy participants were asked to randomly drink, in a crossover design, instant coffee (Coffee); instant coffee and 10% whole milk (Milk); or instant coffee, sugar, and nondairy creamer already premixed (Sugar/NDC). All 3 treatments provided the same amount of total CGA (332 mg). Blood was collected for 12 h after ingestion and plasma samples treated using a liquid-liquid extraction method that included a full enzymatic cleavage to hydrolyze all CGA and conjugates into phenolic acid equivalents. Hence, we focused our liquid chromatography-Electrospray ionization-tandem MS detection and quantification on caffeic acid (CA), ferulic acid (FA), and isoferulic acid (iFA) equivalents. Compared with a regular black instant coffee, the addition of milk did not significantly alter the area under the curve (AUC), maximum plasma concentration (C(max)), or the time needed to reach C(max) (T(max)). The C(max) of CA and iFA were significantly lower and the T(max) of FA and iFA significantly longer for the Sugar/NDC group than for the Coffee group. However, the AUC did not significantly differ. As a conclusion, adding whole milk did not alter the overall bioavailability of coffee phenolic acids, whereas sugar and nondairy creamer affected the T(max) and C(max) but not the appearance of coffee phenolics in plasma.

Plasma appearance and correlation between coffee and green tea metabolites in human subjects

Coffee and green tea are two of the most widely consumed hot beverages in the world. Their respective bioavailability has been studied separately, but absorption of their respective bioactive phenolics has not been compared. In a randomised cross-over design, nine healthy subjects drank instant coffee and green tea. Blood samples were collected over 12 h and at 24 h to assess return to baseline. After green tea consumption, (-)-epigallocatechin (EGC) was the major catechin, appearing rapidly in the plasma; (-)-EGC gallate (EGCg) and (-)-epicatechin (EC) were also present, but (-)-EC gallate and C were not detected. Dihydroferulic acid and dihydrocaffeic acid were the major metabolites that appeared after coffee consumption with a long time needed to reach maximum plasma concentration, suggesting metabolism and absorption in the colon. Other phenolic acid equivalents (caffeic acid (CA), ferulic acid (FA) and isoferulic acid (iFA)) were detected earlier, and they peaked at lower concentrations. Summations of the plasma area under the curves (AUC) for the measured metabolites showed 1.7-fold more coffee-derived phenolic acids than green tea-derived catechins (P = 0.0014). Furthermore, we found a significant correlation between coffee metabolites based on AUC. Inter-individual differences were observed, but individuals with a high level of CA also showed a correspondingly high level of FA. However, no such correlation was observed between the tea catechins and coffee phenolic acids. Correlation between AUC and maximum plasma concentration was also significant for CA, FA and iFA and for EGCg. This implies that the mechanisms of absorption for these two classes of compounds are different, and that a high absorber of phenolic acids is not necessarily a high absorber of catechins.

Cholesterol-lowering properties of amaranth grain and oil in hamsters.

Amaranth was an important ancient grain and has current nutritional potential, being high in protein, fiber, lysine, magnesium, calcium, and squalene. Limited, inconsistent evidence demonstrates amaranth grain or oil can lower cholesterol in animal models. In the present study, hamsters received hypercholesterolemic diets consisting of a control, 10 or 20% Amaranthus cruentus grain, or 2.5 or 5% crude amaranth oil for four weeks. Amaranth oil (5%) decreased total and non-high-density lipoprotein (HDL) cholesterol by 15 and 22%, respectively, compared to control. Amaranth grain (20%; providing 1.4% amaranth oil) lowered non-HDL cholesterol and raised HDL cholesterol. Amaranth grain and oil decreased very low-density lipoprotein (VLDL) cholesterol by 21-50%; and increased fecal excretion of particular neutral sterols and the bile acid ursodeoxycholate. Amaranth oil (5%) additionally increased the cholesterol synthesis rate, possibly due to compensatory mechanisms; and decreased hepatic cholesterol ester, indicating reduced cholesterol ester availability for VLDL secretion and consistency with reduced VLDL cholesterol. Amaranth thus affected absorption of cholesterol and bile acids, cholesterol lipoprotein distribution, hepatic cholesterol content, and cholesterol biosynthesis. Amaranth grain and oil did not affect these pathways identically.

Dose‐dependent absorption of chlorogenic acids in the small intestine assessed by coffee consumption in ileostomists

SCOPE Until now, the question of how the ingested doses of chlorogenic acids (CGA) from coffee influence their absorption and metabolism remains unresolved. To assess absorption in the small intestine, we performed a dose-response study with a randomized, double-blinded, crossover design with ileostomist subjects. METHODS AND RESULTS After a polyphenol-free diet, the volunteers consumed, on three separate occasions, coffee with different total CGA contents (high 4525 μmol; medium 2219 μmol; low 1053 μmol). CGA concentrations in plasma, ileal effluent, and urine were subsequently determined by HPLC-DAD-ESI-MS and -ESI-MS/MS. The results show that the consumption of higher CGA concentrations leads to a faster ileal excretion. This corresponds to a renal excretion of 8.0 ± 4.9% (high), 12.1 ± 6.7% (medium), and 14.6 ± 6.8% (low) of total CGA and metabolites. Glucuronidation of CGA became slightly greater with increasing dose. After enzyme treatment, the area under the curve (AUC)(0-8h) for CGA metabolites in plasma was 4412 ± 751 nM × h(0-8) (-1) (high), 2394 ± 637 nM × h(0-8) (-1) (medium), 1782 ± 731 nM × h(0-8) (-1) (low), respectively. Additionally, we were able to identify new metabolites of CGA in urine and ileal fluid. CONCLUSION We conclude that the consumption of high CGA concentrations via coffee might influence the gastrointestinal transit time and consequently affect CGA absorption and metabolism.