Kinetics of volatile organic compounds (VOCs) released by roasted Coffee during the first ten days after processing

The quality of coffee is linked to the aroma created by the chemical reactions that occur during the roasting process. While it is generally thought that roasted coffee is a stable product with a relatively long shelf-life, little information is available on the evolution (kinetic) of the volatile organic compounds (VOCs) in the days immediately following the process. The aim of this study is to determine the evolution of VOCs released by coffee beans, on samples of Coffea arabica (three different origins) and Coffea canephora (1 single origin), by using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) 24 hours after roasting, and for the next 9 days. Results confirmed the differences already highlighted in previous studies between the VOCs spectra of the two species. There were also significant differences in the intensity of emissions for the different origins of Coffea arabica, with the highest VOCs amount over time always detected in the Honduras Arabica samples. The involved detected protonated ions were grouped into three classes: compounds (ppbv) present with decreasing quantity ; weakly increasing; almost constant trend; or always increasing. A complex dynamic emerged for the different protonated ions over time, which not only affects the mass spectra of the different species but also influences the configuration of the mass spectra of the different geographical zones of production

Comparative analysis of Volatile Compounds (potential aromatic ability) in the fruit of 15 olive Italian cultivars

Virgin olive oils (VOOs) are characterized by peculiar flavors appreciated by the consumers all over the world. Their organoleptic characteristics depend on the aromatic properties of the fruits of the different cultivars, which will originate the final products. VOCs spectra of fifteen certified Italian olive cultivars of the University of Florence Germplasm collection, chosen as their different geographical origin, diffusion, and product purpose, were acquired using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS). The VOCs analyses highlighted a great variability among the fifteen cultivars, mostly due to compounds (C6 and C5) deriving from polyunsaturated fatty acids through the LOX pathway. The early identification in the olive fruit of these compounds which are considered among the major contributors to the positive VOOs attributes, would be useful to produce high quality olive oils, and get useful information to individuate the best parents for the genetic improvement.

Monitoring in real time the changes in VOCS emission in sunflower and extra virgin olive oil upon heating by PTR-TOF-MS

In this work the emission of volatile organic compounds (VOCs) upon the heating process of an extra virgin olive oil (EVOO) and a high oleic sunflower oil (SFO) was evaluated in real time by spectrometry. Two tests were carried out, in the first VOCs emitted from both kinds of oil were measured at room temperatures (not heated, NH) and at 180°C; in the second test, VOCs emission for selected masses were monitored under increasing temperatures over time: at room temperature not heated oils (NH), 60, 90, 120, 150, and 180°C, respectively. The spectra were acquired using a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS). The total VOCs emission increased at 180°C, determined both by the rise of the amount of compounds present in the NH samples and by the formation of new masses generated by oxidative chemical reaction from triglycerides and fatty acids. From the set of results it is evident that a good control of the temperatures can be useful in reducing the quantities of masses potentially harmful to health in human food

Higher circulating levels of proneurotensin are associated with increased risk of incident NAFLD

BackgroundNeurotensin (NT), an intestinal peptide able to promote fat absorption, is implicated in the pathogenesis of obesity. Increased levels of proneurotensin (pro-NT), a stable NT precursor fragment, have been found in subjects with nonalcoholic fatty liver disease (NAFLD); however, whether higher pro-NT levels are associated with an increased NAFLD risk independently of other metabolic risk factors is unsettled. MethodsUltrasound-defined presence of NAFLD was assessed on 303 subjects stratified into tertiles according to fasting pro-NT levels. The longitudinal association between pro-NT levels and NAFLD was explored on the study participants without NAFLD at baseline reexamined after 5 years of follow-up (n = 124). ResultsIndividuals with higher pro-NT levels exhibited increased adiposity, a worse lipid profile, and insulin sensitivity as compared to the lowest tertile of pro-NT. Prevalence of NAFLD was progressively increased in the intermediate and highest pro-NT tertile as compared to the lowest tertile. In a logistic regression analysis adjusted for several confounders, individuals with higher pro-NT levels displayed a raised risk of having NAFLD (OR = 3.43, 95%CI = 1.48-7.97, p = 0.004) than those in the lowest pro-NT tertile. Within the study cohort without NAFLD at baseline, subjects with newly diagnosed NAFLD at follow-up exhibited higher baseline pro-NT levels than those without incident NAFLD. In a cox hazard regression analysis model adjusted for anthropometric and metabolic parameters collected at baseline and follow-up visit, higher baseline pro-NT levels were associated with an increased risk of incident NAFLD (HR = 1.52, 95%CI = 1.017-2.282, p = 0.04). ConclusionHigher pro-NT levels are a predictor of NAFLD independent of other metabolic risk factors

Are circulating Mg2+ levels associated with glucose tolerance profiles and incident type 2 diabetes?

Magnesium (Mg2+) is an enzyme co-factor that plays a key role in many biochemical reactions, as well as in glucose metabolism. Clinical evidences have demonstrated that depletion of serum Mg2+ increases exponentially with the duration of type 2 diabetes mellitus (T2DM). Diabetes is associated with low Mg2+, and hypomagnesemia is associated with insulin resistance, inflammation, and increased risk for cardiovascular disease. In subjects at high risk of inflammation and insulin resistance, supplementation of Mg2+ alone ameliorates both phenotypes, slowing the development and progression of hepatic steatosis. We analyze the relationship between serum Mg2+ levels and the onset of T2DM in a large cohort of well-characterized adult white individuals participating in the CATAMERI study, who were reexamined after a mean follow-up of 5.6 ± 0.9 years. In our analysis we acquired a significant negative correlation between Mg2+ levels, fasting glucose, and 2h-post load glucose in subjects who underwent an OGTT. Moreover, Mg2+ levels correlated negatively with fasting insulin levels, and positively with the lipid profile. As for the detrimental effect of lower circulating Mg2+ levels, our data revealed a significant reduction of T2DM risk of about 20% for each 1 mg/dL increase of circulating Mg2+. The present results are consistent with the theory that Mg2+ supplementation could ameliorate insulin sensitivity reducing the risk to develop T2DM

Volatile compounds from different fruit parts of two cultivars of Cydonia oblonga

Quince is characterized as a fragrant fruit which, unlike other pomes (apple, pear), is not used for fresh consumption due to its astringency and compactness, but only in its processed form (jams, jelly, distillery products, and nutraceutical compounds). As a consequence, there is little knowledge currently available concerning the characteristics of the fruit, and in particular its aromatic and chemotaxonomic patterns. In this work, carpometric, chemometric and spectrophotometric measurements were performed on quince fruits. VOCs emitted by different tissues or parts of the fruit were studied to describe its aromatic profile. The study was carried out on the fruits of an old, well-known cultivar (‘Gigante di Wranja’, commonly called ‘Wranja’) and a new Tuscan accession. Intact, halved and solely pulp (cubed) samples were evaluated for each individual fruit. Data obtained from VOC analysis through Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) were evaluated by multivariate statistical analysis. The spectra obtained from the intact fruit samples showed a higher amount of masses corresponding to terpenes or terpenoid compounds, which fundamentally characterize the aroma of this type of fruit; these substances were found to be much less present in the VOCs emitted by the pulp, where high values of masses linked to the maturation processes were instead found

Tuberomics: a molecular profiling for the adaption of edible fungi (Tuber magnatum Pico) to different natural environments

Background: Truffles are symbiotic fungi that develop underground in association with plant roots, forming ectomycorrhizae. They are primarily known for the organoleptic qualities of their hypogeous fruiting bodies. Primarily, Tuber magnatum Pico is a greatly appreciated truffle species mainly distributed in Italy and Balkans. Its price and features are mostly depending on its geographical origin. However, the genetic variation within T. magnatum has been only partially investigated as well as its adaptation to several environments. Results: Here, we applied an integrated omic strategy to T. magnatum fruiting bodies collected during several seasons from three different areas located in the North, Center and South of Italy, with the aim to distinguish them according to molecular and biochemical traits and to verify the impact of several environments on these properties. With the proteomic approach based on two-dimensional electrophoresis (2-DE) followed by mass spectrometry, we were able to identify proteins specifically linked to the sample origin. We further associated the proteomic results to an RNA-seq profiling, which confirmed the possibility to differentiate samples according to their source and provided a basis for the detailed analysis of genes involved in sulfur metabolism. Finally, geographical specificities were associated with the set of volatile compounds produced by the fruiting bodies, as quantitatively and qualitatively determined through proton transfer reaction-mass spectrometry (PTR-MS) and gas-chromatography mass spectrometry (GC-MS). In particular, a partial least squares-discriminant analysis (PLS-DA) model built from the latter data was able to return high confidence predictions of sample source. Conclusions: Results provide a characterization of white fruiting bodies by a wide range of different molecules, suggesting the role for specific compounds in the responses and adaptation to distinct environments

Glucagon kinetics assessed by mathematical modelling during oral glucose administration in people spanning from normal glucose tolerance to type 2 diabetes

Background/ObjectivesGlucagon is important in the maintenance of glucose homeostasis, with also effects on lipids. In this study, we aimed to apply a recently developed model of glucagon kinetics to determine the sensitivity of glucagon variations (especially, glucagon inhibition) to insulin levels (“alpha-cell insulin sensitivity”), during oral glucose administration.Subjects/MethodsWe studied 50 participants (spanning from normal glucose tolerance to type 2 diabetes) undergoing frequently sampled 5-hr oral glucose tolerance test (OGTT). The alpha-cell insulin sensitivity and the glucagon kinetics were assessed by a mathematical model that we developed previously.ResultsThe alpha-cell insulin sensitivity parameter (named SGLUCA; “GLUCA”: “glucagon”) was remarkably variable among participants (CV=221%). SGLUCA was found inversely correlated with the mean glycemic values, as well as with 2-hr glycemia of the OGTT. When stratifying participants into two groups (normal glucose tolerance, NGT, N=28, and impaired glucose regulation/type 2 diabetes, IGR_T2D, N=22), we found that SGLUCA was lower in the latter (1.50 ± 0.50·10-2vs. 0.26 ± 0.14·10-2 ng·L-1GLUCA/pmol·L-1INS, in NGT and IGR_T2D, respectively, p=0.009; “INS”: “insulin”).ConclusionsThe alpha-cell insulin sensitivity is highly variable among subjects, and it is different in groups at different glucose tolerance. This may be relevant for defining personalized treatment schemes, in terms of dietary prescriptions but also for treatments with glucagon-related agents

Aroma fingerprinting in green and roasted beans and ground coffee by Proton PTR-ToF-MS

The research is based on the utilization of the PTR-TOF-MS headspace analysis to distinguish, by VOCs, different matrices in coffee beans. Two species, Coffea arabica and Coffea canephora, contribute to the total production; the commercial value of the coffee depends on the species (Coffea arabica generally being considered of highest quality) and on geographical origin, including not only the pedoclimatic conditions, but also the processing systems (dry or wet). Green beans, medium roasted beans and the related ground coffee of both C. arabica and C. canephora, coming respectively from 7 and 5 different geographical zones of Africa, America and Asia, were comparatively evaluated. By a PLS-DA analysis the green beans samples resulted sharply separated from the roasted beans and from the ground coffees, with a quantitative and qualitative increase of VOCs. The main protonated masses discriminating C. arabica from C. canephora were, in the green beans, m/z = 33.033 (tentatively identified as methanol), 49.010 (TI: methanethiol), 81.069 (TI: terpene fragment), 95.086 (TI: terpene fragment), 101.060 (TI: pentanedione) and, in the class of roasted beans, m/z = 69.033 (TI: furan), 85.028 (TI: furanone), 97.028 (TI: furfural), 111.045 (TI: acetilfuran), 141.055 (TI: furfurilacetate). In the arabica group, roasted beans and ground coffee resulted very well distinguished, without regard of the country of production. The different Indian samples (two canephora and one arabica) were correctly classified. The separation between the two subgroups roasted beans and ground coffee was determined by quantitative differences of the same protonated masses, as m/z = 43.054 (TI: alkyl fragment), 61.028 (TI: acetic acid), 85.028 (TI: furanone), 148.076 (TI: furfurilpyrrole). These results show that by the PTR-TOF-MS headspace VOCs analysis it is possible to check the correct attribution of the roasted beans and ground coffees to the right category (arabica or canephora), without regard of geographical origin of production

Comparing image (fractal analysis) and electrochemical (impedance spectroscopy and electrolyte leakage) techniques for the assessment of the freezing tolerance in olive

Olive growth and productivity are limited by low temperatures mainly during winter, but sometimes also in spring and fall. The most effective way to avoid these damages in areas subjected to these climatic conditions is to select least susceptible varieties, but the choice of the right method to determine cold hardiness is extremely difficult. The aims of the work were (1) to assess LT50 (lethal temperature at which 50% of damage in plants subjected to low temperatures occurs) of some olive varieties in two seasons (summer and winter) and (2) to assess the reliability of different methods to evaluate cold hardiness. LT50 was determined on 21 different olive (Olea europaea L.) Italian varieties by leaf and shoot electrolyte leakage, shoot impedance spectroscopy and leaf color determination of fractal spectrum. All the experiments were conducted on non-acclimated and cold-acclimated plants. Our results showed that all the three methods were able to detect damages on olive plants after exposure to low temperatures, with leaves appearing more sensitive to cold stress than shoots. Among these methods, fractal analysis could be very useful in assessing cold hardiness of plants on the basis of visible injury, without sophisticated or expensive instruments and in a reliable and cost-effective way, using only a scanning device, a personal computer and dedicated freeware software.[...