NMR study on the oxidation of vegetable oils for assessing the antioxidant function of trehalose

Authors: Liu, Zengshe - Kevin; Vermillion, Karl; JIN, CAN - Chinese Academy Of Forestry; WANG, XU - Henan Agricultural University; ZHAO, WEI - Shandong Fuyang Biotechnology Co

Submitted to: Biocatalysis and Agricultural Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2021
Publication Date: 8/24/2021
Citation: Liu, Z., Vermillion, K., Jin, C., Wang, X., Zhao, W. 2021. NMR study on the oxidation of vegetable oils for assessing the antioxidant function of trehalose. Biocatalysis and Agricultural Biotechnology. 36. Article 102134. https://doi.org/10.1016/j.bcab.2021.102134.
DOI: https://doi.org/10.1016/j.bcab.2021.102134

Interpretive Summary: Deep-fat frying (DFF) is one of the most common cooking techniques used in domestic and industrial food preparation. During the DFF process, edible oil is exposed to high temperature in the presence of air and moisture, and various chemical reactions take place which causes undesirable consequences to flavor, shelf-life and consumers’ health. In this research, we found that a natural antioxidant, trehalose, a sugar molecule consisting of the binding of two glucoses, shows excellent antioxidant activity for vegetable oils studied such as soybean oil, corn oil, canola oil, cottonseed oil and peanut oil in frying conditions. Nuclear magnetic resonance (NMR) spectroscopy was used to fingerprint the resulting changes in oil structure. NMR is a very useful technique and requires a very small sample and short processing time. This research would expedite the practical application of natural antioxidants in edible oils when the DFF process is used in the food industry.

Technical Abstract: The objective of this study was to investigate the antioxidant activity of trehalose in vegetable oils after 16 h deep-frying at 180 °C by using nuclear magnetic resonance (NMR) spectroscopy. 1H NMR spectroscopy is a useful technique for determining structure which requires small sample volumes and short processing time. The results of this study indicate the oxidation stability of vegetable oils can be improved with the addition of trehalose at 0.05% (w/w) concentration. The antioxidant activity of trehalose positively affected all vegetable oils studied with notable differences when used in conjunction with soybean oil. For example, the measured percent loss of olefinic protons in soybean oil (oil-0 control) changed from 6.17 to 2.52 (integral value) in sample soybean oil-1 with the addition of trehalose. Similarly, the percent loss of bisallylic protons changed from 8.19 to 3.32. Further, with respect to the percent loss of allylic protons changing from 3.02 to 0, the oxidation of an allylic proton was greatly depressed. Trehalose improved the oxidation stability of soybean oil much better than that of corn oil, canola oil, cottonseed oil and peanut oil. In summary, trehalose can be used as a safe and effective antioxidant for these edible oils.