Secondary metabolites are molecules with unlimited applications that have been gaining importance in various industries and studied from many angles. They are mainly used for their bioactive capabilities, but due to the improvement of sensibility in analytical chemistry, they are also used for authentication and as a quality control parameter for foods, further allowing to help avoid food adulteration and food fraud, as well as helping understand the nutritional value of foods. This manuscript covers the examples of secondary metabolites that have been used as qualitative and authentication molecules in foods, from production, through processing and along their shelf-life. Furthermore, perspectives of analytical chemistry and their contribution to metabolite detection and general perspectives of metabolomics are also discussed.

Bioactive compounds derived from plants are secondary metabolites that can act through various bioactivities, namely as antioxidant, antimicrobial, anti-inflammatory, anti-hypertensive, and hypoglycemic agents. Combined with the pressure generated by consumers for more natural products with beneficial effects on health, these compounds may be suitable candidates to act as preservatives in food products. For this purpose, the extraction process becomes essential for the acquisition of a quality extract with efficiency and with the desired final properties. Therefore, the main objective of this work was to perform the optimization of the extraction yield of olive leaves (Olea europaea L.), by applying response surface methodology (RSM) and employing dynamic maceration as extraction technique. Three factors were analyzed: time (F1), temperature (F2), and solvent (F3), ranging from 5 to 120 min, 25 to 100 °C, and from 0 to 100% ethanol, respectively. The study used the Box Behnken design, relying on 17 individual randomized runs. The response was the dry weight of the extract (Y1), which ranged from 21.1 to 90.5 mg. The optimization studies pointed to the increase of yield with the increase of time and temperature, but inversely by applying higher time and lower temperature values and higher temperature and lower time values. The highest yield of the dry extract was achieved at 120 min (F1), 25 °C (F2), and 87% (F3) of ethanol:water. Future studies will be carried out to analyze the preservative effects of incorporating olive extract in foods, as well as analysis of other response for optimizing the best food preserving extract.

To meet the market demand for high-quality products, researchers and manufacturers have invested in the development of accurate methods for estimating shelf-life. Tests that consider the simultaneous effects of different parameters on food degradation are useful tools in shelf-life studies, as these parameters can directly influence quality and safety. With this in mind, the objective of this review is to gather pertinent information from recent studies (2006–2022) pertaining to multivariate analysis applied in accelerated shelf-life tests in order to facilitate a comprehensive understanding. The review focuses on multivariate techniques commonly employed in accelerated shelf-life modeling, namely, principal components analysis, partial least squares regression, orthogonal projections to latent structures discriminant analysis, and hierarchical cluster analysis. Through an extensive literature review, the collected data represent the evolution of these methods, taking into account current trends, advances in food shelf-life techniques, and future perspectives. It was observed that the recent literature provides limited information on the determination of shelf-life under multiple accelerated factors. However, the studies analyzed showed that multivariate analysis can be a useful tool in the interpretation of quality characteristics and can accurately predict the shelf-life of foods compared to univariate kinetic procedures. The multivariate statistical methods addressed in this work are presented as a promising method for foods tested, being applied together with different chemometric techniques. This comprehensive review contributes to the body of knowledge surrounding accelerated shelf-life testing, offering valuable insights for researchers, manufacturers, and stakeholders in the food industry.