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Terpenoids are a class of compounds found in hops which are responsible for the distinctive hop aromas in beer. Changes in terpenoid composition during fermentation as a result of yeast biotransformation influences beer aroma, but the pathways involved in these reactions are yet to be fully understood. In this study, eleven terpenoid standards (geraniol, nerol, citronellol, citral, α-terpineol, citronellyl acetate, caryophyllene, linalool, limonene, β-pinene and myrcene) were individually added to a model beer system fermented with commercially available Saccharomyces cerevisiaeyeast (SafAle US-05). Volatile organic compounds (VOCs) were measured before and after fermentation with headspace solid-phase microextraction gas chromatography/mass spectrometry (SPME-GC/MS). Upon adding a single terpenoid standard to the model beer system, multiple terpenoid products were detected in the resulting beer at the end of fermentation. For example, when geraniol (10 ppm) was added, geraniol, citronellol, citronellyl acetate, citronellal, nerol, dihydrolinalool and dihydrocitronellol were detected at the end of fermentation. This research illustrates the importance of studying individual terpenoids as it provides valuable insights into the complex chemistry of beer. This information can aid in the optimisation of brewing to enhance the production of the flavours and aromas in beer desired by consumers.

•Physio-chemical properties of four Italian flint maize landraces were analyzed.•SPME GC–MS and PTR-TOF-MS were applied for volatilome characterization.•Flours volatilome and nutritional traits are preserved into polenta.•Cooking triggered Maillard reaction, lipid oxidation and VOCs evaporation.

After harvest, apples are stored at low temperature to slow down the ripening physiological processes. This strategy can, however, also promote the development of superficial scald, a chilling injury-related disorder showing brown-discoloured areas on the fruit skin, totally compromising its marketability. To examine thoroughly the underlying physiological mechanisms and genetic control of superficial scald, the “Scald-Cold” project, a three-year Interegional Project Network, was granted by the European Region Tyrol, South Tyrol and Trentino (EGTC). The project is centred on a comprehensive approach, integrating into a joint effort different scientific disciplines, ranging from genetics and transcriptomics to NIR spectroscopy and hyperspectral imaging, together with the employment of distinct postharvest storage technologies distinguished by a specific regime of low oxygen. The core of this project aims to disclose novel regulatory processes of this disorder, providing new series of tools important for both the scientific and technical communities interested in apple breeding and postharvest. The “Scald-Cold” project will identify new molecular markers suitable for the selection of new apple varieties genetically resistant to superficial scald, while developing tools for an early detection of this phenomenon.

This study investigated the effects of chewing rate and food composition on in vivoaroma release and perception of composite foods. Bread or sponge cake paired with varying sugar content and viscosity strawberry jams, spiked with citral and limonene, were examined. In-nose release was characterized using Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometry (PTR-ToF-MS). Simultaneously, Time-Intensity (TI) profiling assessed citrus aroma perception (n= 8, triplicate) while fast and slow chewing protocols were applied (fast: 1.33 chews/s; slow 0.66 chews/s; each for 25 s). Chewing rate did not significantly impact the area under the curve and maximum intensity of in vivocitral and limonene release and citrus aroma perception. Faster chewing rates significantly decreased the time to reach maximum intensity of aroma release (p< 0.05) and citrus aroma perception (p< 0.001). Faster chewing rates probably accelerated structural breakdown, inducing an earlier aroma release and perception without affecting aroma intensity. Adding carriers to jams significantly (p< 0.05) increased aroma release, while perceived citrus aroma intensity significantly (p< 0.05) decreased regardless of chewing rate. In conclusion, chewing rate affects the temporality of in vivoaroma release and perception without affecting its intensity, and carrier addition increases in vivoaroma release while diminishing aroma perception.

Proton transfer reaction‐mass spectrometry (PTR‐MS), a direct injection mass spectrometric technique based on an efficient implementation of chemical ionisation, allows for fast and high‐sensitivity monitoring of volatile organic compounds (VOCs). The first implementations of PTR‐MS, based on quadrupole mass analyzers (PTR‐Quad‐MS), provided only the nominal mass of the ions measured and thus little chemical information. To partially overcome these limitations and improve the analytical capability of this technique, the coupling of proton transfer reaction ionisation with a time‐of‐flight mass analyser has been recently realised and commercialised (PTR‐TOF‐MS). Here we discuss the very first application of this new instrument to agro‐industrial problems and dairy science in particular. As a case study, we show here that the rapid PTR‐TOF‐MS fingerprinting coupled with data‐mining methods can quickly verify whether the storage condition of the milk affects the final quality of cheese and we provide relevant examples of better compound identification in comparison with the previous PTR‐MS implementations. In particular, ‘Trentingrana’ cheese produced by four different procedures for milk storage are compared both in the case of winter and summer production. It is indeed possible to set classification models with low prediction errors and to identify the chemical formula of the ion peaks used for classification, providing evidence of the role that this novel spectrometric technique can play for fundamental and applied agro‐industrial themes. Copyright © 2010 John Wiley & Sons, Ltd.

Metal oxides are ideal for the fabrication of gas sensors: they are sensitive to many gases while allowing the device to be simple, tiny, and inexpensive. Nonetheless, their lack of selectivity remains a limitation. In order to achieve good selectivity in applications with many possible interfering gases, the sensors are inserted into an electronic nosethat combines the signals from nonselective sensors and analyzes them with multivariate statistical algorithms in order to obtain selectivity. This review analyzes the scientific articles published in the last decade regarding electronic noses based on metal oxide nanowires. After a general introduction, Section 2 discusses the issues related to poor intrinsic selectivity. Section 3 briefly reviews the main algorithms that have hitherto been used and the results they can provide. Section 4 classifies the recent literature into fundamental research, agrifood, health, security. In Section 5, the literature is analyzed regarding the metal oxides, the surface decoration nanoparticles, the features that differentiate the sensors in a given array, the application for which the device was developed, the algorithm used, and the type of information obtained. Section 6 concludes by discussing the present state and points out the requirements for their use in real-world applications.

Condiments such as spreads, dressings, or sauces are usually consumed together with carrier foods such as breads or vegetables. Dynamic interactions between condiments and carriers occur during consumption, which can influence aroma release and perception. This study investigated in vivoaroma release (PTR-MS) and dynamic sensory perception (time–intensity) of mayonnaises spiked with lemon aroma (limonene, citral). Mayonnaises were assessed without and with carrier foods (bread, potato). When different mayonnaises were consumed and assessed alone, aroma release and intensity perception were positively correlated. Interestingly, when mayonnaises were combined with carriers, aroma release and perception were no longer positively correlated. Addition of carriers increased release of limonene and citral into the nasal cavity during consumption but decreased perceived aroma intensity of condiments. The increase in aroma release induced by the carriers can be explained by differences in oral processing behaviors and by the increased surface area of mayonnaise-carrier combinations. Carrier addition is likely to modulate aroma perception of composite foods by cross-modal texture–aroma interactions. This work demonstrates that not only physicochemical characteristics of foods but also cross-modal interactions play a role in influencing flavor perception of composite foods.

To elucidate the physiology underlying the development of superficial scald in pears, susceptible “Blanquilla” fruit was treated with different compounds that either promoted (ethylene) or repressed (1-methylcyclopropene and lovastatin) the incidence of this disorder after 4 months of cold storage. Our data show that scald was negligible for the fruit treated with 1-methylcyclopropene or lovastatin, but highly manifested in untreated (78% incidence) or ethylene-treated fruit (97% incidence). The comparison between the fruit metabolomic profile and transcriptome evidenced a distinct reprogramming associated with each treatment. In all treated samples, cold storage led to an activation of a cold-acclimation-resistance mechanism, including the biosynthesis of very-long-chain fatty acids, which was especially evident in 1-methylcyclopropane-treated fruit. Among the treatments applied, only 1-methylcyclopropene inhibited ethylene production, hence supporting the involvement of this hormone in the development of scald. However, a common repression effect on the PPOgene combined with higher sorbitol content was found for both lovastatin and 1-methylcyclopropene-treated samples, suggesting also a non-ethylene-mediated process preventing the development of this disorder. The results presented in this work represent a step forward to better understand the physiological mechanisms governing the etiology of superficial scald in pears.

Species that cannot be easily distinguished based on morphology, but which form distinct phylogenetic lineages based on molecular markers, are often referred to as cryptic species. They have been proposed in a number of fungal genera, including the basidiomycete genus Fomes. The main aim of this work was to test new methods for species delimitation in cryptic lineages of polypores, and to define useful characters for species identification.

To decipher the transcriptomic regulation of the on-tree fruit maturation in pear cv. ‘Abate Fetel’, a RNA-seq transcription analysis identified 8939 genes differentially expressed across four harvesting stages. These genes were grouped into 11 SOTA clusters based on their transcriptional pattern, of which three included genes upregulated while the other four were represented by downregulated genes. Fruit ripening was furthermore investigated after 1 month of postharvest cold storage. The most important variation in fruit firmness, production of ethylene and volatile organic compounds were observed after 5 days of shelf-life at room temperature following cold storage. The role of ethylene in controlling the ripening of ‘Abate Fetel’ pears was furthermore investigated through the application of 1-methylcyclopropene, which efficiently delayed the progression of ripening by reducing fruit softening and repressing both ethylene and volatile production. The physiological response of the interference at the ethylene receptor level was moreover unraveled investigating the expression pattern of 12 candidate genes, initially selected to validate the RNA-seq profile. This analysis confirmed the effective role of the ethylene competitor in downregulating the expression of cell wall (PG) and ethylene-related genes (ACS, ACO, ERS1, and ERS2), as well as inducing one element involved in the auxin signaling pathway (Aux/IAA), highlighting a possible cross-talk between these two hormones. The expression patterns of these six elements suggest their use as molecular toolkit to monitor at molecular level the progression of the fruit on-tree maturation and postharvest ripening.