Food volatilomics by direct injection mass spectrometry

Volatile metabolites play a pivotal role in food science and technology across various stages of the production chain. They are integral to plant ecology and physiology, influencing plant responses and signaling amidst biotic or abiotic stresses. Additionally, these compounds act as both drivers and byproducts of fruit changes during ripening and storage, profoundly shaping the sensory experience of food from its odor, flavor, and aroma before, during, and after consumption.

Furthermore, due to their spontaneous and continuous release, volatile compounds offer a non-invasive and rapid means for assessing food samples and monitoring biological and technological processes in real-time. Consequently, the analysis of the food volatolome is of significant interest, particularly in an omic approach, where it can offer high sensitivity and a broad dynamic range. This capability is crucial as volatile compounds can elicit biological or sensory effects at varying, sometimes minute, concentrations. Additionally, rapid and non-invasive measurements enable the screening of extensive sample sets and the monitoring of swift processes.
These challenges are effectively addressed by various Direct Injection Mass Spectrometry (DIMS) methods, with Proton Transfer Reaction Mass Spectrometry (PTR-MS) standing out. While these techniques may lack the specificity of chromatographic methods, they compensate with their speed, non-invasiveness, and high sensitivity, even without prior sample pretreatment.
This seminar, following a brief overview of a prototypical DIMS setup based on PTR-MS tailored for agroindustrial applications, aims to highlight the advantages and drawbacks of DIMS in food volatolomics. This will be achieved by outlining selected applications explored at the Volatile Compound Facility at FEM.
Firstly, PTR-MS profiling of berry fruits, apples, and dairy products has been instrumental in exploring sample sets and establishing classification or calibration models that correlate the food volatolome with sensory or genomic data. This facilitates efficient identification of quantitative trait loci related to fruit volatile compounds, development of instrumental models of sensory quality for realistic "sensomic" studies, and identification of typicality markers. Secondly, a fully automated system for monitoring volatile compounds released during biological or technological processes has been devised. This system has been employed to investigate various microbiological processes such as bread leavening, lactic and alcoholic fermentation, and spoilage during storage. Finally, DIMS enables the examination of the interaction between food and humans or animal models, both from a sensory and health perspective. This involves measuring metabolites released during food consumption (nose-space analysis) or in exhaled breath (breath analysis). Additionally, some recent advancements aimed at enhancing the specificity of PTR-MS-based methods without compromising their positive attributes are also discussed.

Biosketch

Franco Biasioli is a physicist by training and holds a qualification as a full professor in analytical chemistry. Currently, he leads the Sensory Quality Unit at the Innovation and Research Centre of Fondazione Edmund Mach, where he has established a PTR-MS based facility for high-throughput volatilome profiling. His research primarily focuses on the applications of direct injection mass spectrometry in food science and technology, encompassing rapid product characterization, phenotyping, online process monitoring, correlation of food volatile compound profiles with sensory analysis and genomics, as well as nose-space measurements. Additionally, he possesses expertise in multivariate analysis and data mining methods applied to mass spectrometry and sensory data. He contributed to over 250 ISI papers.