Detection of Aroma Profile in Spanish Rice Paella during Socarrat Formation by Electronic Nose and Sensory Panel

Abstract

Valencian paella is a world-famous dish that is originally from the Valencia Spanish region, in which rice is the basic ingredient along with others such as extra virgin olive oil, vegetables, seafood and/or meat. During the cooking process, the paella rice suffers a loss of moisture and the socarrat is formed, being crunchy and brown in color. The objective of this work was to evaluate the aromas generated during the formation of socarrat in paella rice (P) by an electronic nose (E-nose), discriminating against the aromatic profile of white rice (WR), and validate it with sensory analysis and gas chromatography. The results of the sensory analysis showed a decrease in positive fruity and sweet aromas of some volatile compounds such as hexanal and nonanal, among others, and an increase in roasted aromas due to the appearance of furans and furanones compounds, which is probably associated with socarrat formation. The acrylamide content increased by 33.8–48.3% as the intensity of the thermal treatment rose. The higher value of acrylamide (179.5 ng g−1) was achieved in P. The E-nose was sensitive to changes in the aromatic profile, and the PCA analysis explained 85.7% and 91.6% of the variance for WR and P, respectively. Furthermore, a strong clustering in the thermal treatments was observed, which is related to the composition of volatile compounds.

Electronic Prediction of Chemical Contaminants in Aroma of Brewed Roasted Coffee and Quantification of Acrylamide Levels

“…The aromatic compounds decreased over time, by up to 85.5% for the roasting time of 11 min. These types of compounds are essential in the production of coffee aroma both in the drying and roasting phases [ 23 , 28 ].…”

“…The scientific literature contains studies that discriminate coffee samples with electronic devices. Some researchers [ 28 ] discriminated coffee samples of different qualities from Colombia. Others [ 59 ] classified coffee submitted to different intensities of roasting periods.…”

“…Furthermore, it is an emerging market in terms of organic coffee, and due to its organoleptic properties, like Colombian coffee, Honduran coffee is a quality Arabica coffee. Fresh samples of 150 g were placed onto porcelain plates to be roasted in a conventional oven (model 210, J.P. Selecta ® , Barcelona, Spain) at 215 °C, as described by Barea-Ramos et al [ 28 ]. The roasting times were 8, 9, 10 and 11 min, respectively.…”