Effect of roasting temperature and time on volatile compounds, total tocopherols, and fatty acids of flaxseed oil

Abstract

Roasting affects the physicochemical and nutritional qualities of flaxseed oil (FSO). The FSO samples were extracted from the roasting flaxseeds at 10‐, 20‐, and 30‐min points and at different temperatures (140°C, 160°C, and 180°C). A total of 61 volatile compounds were identified, and the quantity of the volatile compounds increased significantly (p < 0.05) after roasting. The maximum aldehyde (25.83%) and heterocyclic content (29.26%) was obtained from the samples roasted at 200°C for 20 and 30 min, respectively. The predominant fatty acid in FSO samples was linolenic acid (46.01%–49.35%), which changed dynamically during roasting. The loss of α‐, γ‐, and δ‐tocopherol after roasting was 28.73, 109.78, and 6.67 mg/100 g, respectively. The principal component analysis and hierarchical cluster analysis results showed good discrimination of the different FSO samples into three groups, which were mainly related to the roasting time. Therefore, it can be concluded that roasting time has a stronger effect on the volatile composition of FSO than the temperature during the roasting process. This work provides a basis for improving the aroma of FSO. Practical Application The roasting process is used to extract flaxseed oil (FSO) from flaxseeds. Studying the physicochemical properties and quality characteristics of FSO under diverse roasting conditions is an important step in producing FSO in the food industry, which can give precise instructions to produce flaxseed oil in factories. The results of this study document the volatile constituents generated in FSO samples extracted from flaxseeds during roasting, which may help manufacturers, who are trying to develop natural and artificial FSO flavors.

Effects of roasting temperature and duration on color and flavor of a sesame oligosaccharide-protein complex in a Maillard reaction model

“…Comparing the total amino acids of ROP-1, ROP-2, and ROP-3, the total amino acids of ROP-3 decreased more than ROP-2, from which it can conclude that roasting temperature had a greater effect on the degree of Maillard reaction than duration. This conclusion is not consistent with that of Sun et al (2022) , who found roasting duration had a stronger effect on volatile compounds, presumably due to differences in materials and roasting conditions. Notably, the total amino acids decreased less than total sugars, indicating that SOL was easier to participate in the Maillard reaction than SPI because of the weak thermal stability of SOL.…”

“…Therefore, roasting temperature and duration are two important factors influencing the color and flavor formation in the process of roasting sesame seeds. It is noteworthy that roasting temperature affects color differently compared with roasting duration ( Sun et al, 2022 ).…”

Effects of different extraction methods on volatile profiles of flaxseed oils

“…Among the volatile compounds detected by HS–GC–IMS, the variety of aldehydes was the most abundant, which was consistent with the previous study (Sun et al., 2022). A total of 27 aldehydes were detected, including monomers and dimers.…”

“…The volatile compounds of oil are the basic substances of flavor generation, and their formation is closely related to the preparation technology (Chen et al., 2022). It is reported that roasting before pressing can render oil with some unique flavors, such as nutty, almond, and caramel aromas (Sun et al., 2022). Headspace–gas chromatography–ion migration spectrometry (HS–GC–IMS) can be used to establish the fingerprints of volatile compounds in FSOs extracted by different methods.…”

Bleaching techniques impact on some quality parameters in two different cold‐pressed oils obtained at farm scale

“…The content of total tocopherols of hemp and linseed oils obtained in the present study (Table 1) are consistent with the study of Siger and Gornas (2023) which place both species in the group of plants with an average/medium concentration (51–100 mg 100 g −1 oil). In linseed oil, the total tocopherol content was 53.5 mg 100 g −1 , in agreement with the minimum value of the range (56.4–575 mg 100 g −1 ) obtained by several previous experiments in different years and locations (Bozan & Temelli, 2008; Sun et al, 2022; Zhang et al, 2021). Similarly, the total content of tocopherols in hempseed oil (50.8 mg 100 g −1 ) was within the range (41 to 111 mg 100 g −1 ) obtained by Matthäus et al (2006), but lower than the minimum amount obtained by Liang et al (2015) (80 mg 100 g −1 ) in a biennial trial, with γ‐tocopherol as the predominant homologue.…”