Oxidative Stability of Stripped Soybean Oil during Accelerated Oxidation: Impact of Monoglyceride and Triglyceride—Structured Lipids Using DHA as sn-2 Acyl-Site Donors

The current work aimed to clarify the effects of four structured lipids, including monoglycerides with docosahexaenoic acid (2D-MAG), diacylglycerols with caprylic acid (1,3C-DAG), triglyceride with caprylic acid at sn-1,3 and DHA at sn-2 position (1,3C-2D-TAG) and caprylic triglyceride on the oxidative stability of stripped soybean oil (SSO). The results revealed that compared to the blank group of SSO, the oxidation induction period of the sample with 2 wt% 2D-MAG and that with 1,3C-DAG were delayed by 2–3 days under accelerated oxidation conditions (50 °C), indicating that 2D-MAG and 1,3C-DAG prolonged the oxidation induction period of SSO. However, the inhibitory effect of α-tocopherol on SSO oxidation was reduced by 2D-MAG after addition of 2D-MAG to SSO containing α-tocopherol. 2D-MAG exhibited different antioxidative/pro-oxidative effects in the added/non-added antioxidants system. Compared to caprylic triglyceride, DHA at the sn-2 acyl site induced oxidation of structured lipids, thus further promoting the oxidation of SSO. The antioxidant was able to inhibit not only the oxidation of DHA in the SSO, but also the transesterification of sn-2 DHA to sn-1/sn-3 DHA in the structured lipid.

Download Full-text

Linseed oil: Characterization and study of its oxidative degradation

Grasas y Aceites ◽

10.3989/gya.1059182 ◽

2020 ◽

Vol 71 (1) ◽

pp. 337 ◽

Cited By ~ 1

Author(s):

B. M. Berto ◽

R. K.A. Garcia ◽

G. D. Fernandes ◽

D. Barrera-Arellano ◽

G. G. Pereira

Keyword(s):

Fatty Acid ◽

Oxidative Stability ◽

Induction Period ◽

Room Temperature ◽

Linseed Oil ◽

Oxidative Degradation ◽

Acid Value ◽

Quality Parameters ◽

Time Intervals ◽

Accelerated Oxidation

This paper proposes to characterize and monitor the degradation of linseed oil under two oxidation conditions using some traditional oxidative and quality parameters. The experimental section of this study was divided into 2 stages. In the first one, three commercial linseed oil samples (OL1, OL2, and OL3) were characterized according to oxidative stability (90 °C) and fatty acid composition. In the second stage, the OL1 sample, selected due to its availability, was subjected to the following oxidation procedures: storage at room temperature conditions with exposure to light and air (temperature ranging from 7 to 35 °C) for 140 days and accelerated oxidation at 100 °C for 7h. Samples were collected at different time intervals and analyzed for oxidative stability (90 °C), peroxide value, and acid value. The results showed that all the samples presented a similar fatty acid profile and that the OL3 sample showed a higher induction period (p < 0.05). Regarding the oxidative degradation, the induction period of the OL1 sample reduced from 9.7 to 5.7 and 9.7 to 6.3 during 140 days of storage under room temperature and 7 h of accelerated oxidation, respectively. The end of induction period of the OL1 sample is expected to occur within 229 days according to an exponential mathematical model fitted to the induction period values at different temperatures. In addition, the OL1 sample met the limits proposed by Codex and Brazilian regulations for peroxide and acid values during the oxidation time intervals.

Download Full-text