Relationship of Glucosinolate Thermal Degradation and Roasted Rapeseed Oil Volatile Odor

Abstract

This study aims to investigate the effect of glucosinolate (GSL) degradation on the volatile odor of rapeseed oil (RO) during roasting. Volatile compounds of RO and individual GSL contents in the seeds were identified and measured during roasting, separately. Total GSL content decreased by 30.47–84.44%. Nitriles were the key volatile compounds that were negatively correlated with GSLs for all samples. Results indicate that GSL degradation significantly affects the volatile odor of RO and tends to produce low-carbon nitriles. Furthermore, the thermal degradation pathways of GSLs were explored according to the structure of individual GSLs and nitriles. These results provide information for the thermal degradation pathways of GSLs and the formation mechanism of nitriles during seed roasting.

Effect of infrared ray roasting on oxidation stability and flavor of virgin rapeseed oils

“…Rapeseed oils are considered the third largest edible oil source in the world with growing demand and production (Mao et al., 2019). Most rapeseed oils are produced as refined oils with slight flavor and degraded nutritional components, and therefore virgin rapeseed oils (VROs) concentrate growing concern from consumers currently (Kraljić et al., 2018).…”

Flavor of rapeseed oil: An overview of odorants, analytical techniques, and impact of treatment

“…Mao et al. (2019) confirmed that hexanal, nonanal, and octanal were dominant volatiles in non‐roasted rapeseed oil, which were related to the grassy and fatty smelling. Hexanal, heptanal, ( E )‐2‐hexenal, ( E , E )‐2,4‐decadienal, and benzaldehyde were reported to be aroma‐active compounds in commercial fragrant rapeseed oils (virgin rapeseed oil obtained from roasted seeds) (Zhou et al., 2019).…”

“…( E , Z )‐2,6‐Nonadienal is known to be derived from 9‐hydroperoxy‐( E , Z , Z )‐10,12,15‐octadecatrienoic acid. 2‐Methylbutanal, 3‐methylbutanal, and 2‐methylpropanal, related to a malty odor in oil, are generated by Strecker degradation of the corresponding amino acids isoleucine, leucine, and valine during roasting of the seeds (Bonte et al., 2017; Gracka et al., 2016; Mao et al., 2019; Matheis & Granvogl, 2016a; Pollner & Schieberle, 2016; Zhou et al., 2019).…”

“…2‐Phenylethanol appears most frequently in the group of alcohols (Table 1). Significant contents of 1‐hexanol, 3‐methyl‐1‐butanol, and 2‐methyl‐1‐butanol were also identified in the oil from non‐roasted rapeseed (Mao et al., 2019). Flowery and honey‐like smelling 2‐phenylethanol was found as an important odorant in cold‐pressed rapeseed oil, which is also formed via the Ehrlich pathway (Matheis & Granvogl, 2016a).…”

“…Heterocyclic compounds are an essential class of aroma compounds containing pyrazines, pyrroles, pyridines, thiophenes, thiazoles, furans, and so forth that are generated during the Maillard reaction in many heat‐processed foods and are often responsible for their roasted aroma. Heterocyclic compounds positively correlate with applied heating temperature and time (Kraljić et al., 2018; Mao et al., 2019; Park et al., 1995).…”