Plant Extracts Inhibit the Formation of Hydroperoxides and Help Maintain Vitamin E Levels and Omega‐3 Fatty Acids During High Temperature Processing and Storage of Hempseed and Soybean Oils

• Published in: Journal of food science Vol. 84; no. 11; pp. 3147 - 3155
• Main Authors: Kitts, David D., Singh, Anika, Fathordoobady, Farahnaz, Doi, Brenda, Pratap Singh, Anubhav
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-11-2019
• Subjects: Aldehydes; Cannabis - chemistry; Cooking; Edible oils; Evaluation; Fatty acids; Fatty Acids - analysis; Fatty Acids, Omega-3 - analysis; Food; Food Handling - methods; Food industry; Food processing; Food production; Food Storage - methods; GLA; Heat treatment; heating; hempseed oil; High temperature; Hot Temperature; Hydrogen Peroxide - analysis; lipid oxidation; Lipid peroxidation; Lipid Peroxidation - drug effects; Lipids; natural preservatives; Oils & fats; Oxidation; Oxidation process; oxidative stability; Peroxide; Peroxides; Plant extracts; Plant Extracts - pharmacology; Plant Oils - chemistry; Polyunsaturated fatty acids; Processed foods; Rosemary; Rosmarinus - chemistry; Salvia officinalis - chemistry; Seeds - chemistry; Soybean oil; Soybean Oil - chemistry; Soybeans; Stability analysis; Storage; Thyme; Thymus Plant - chemistry; Tocopherol; Tocopherols; Vegetable oils; Vitamin E; Vitamin E - analysis; ω‐3PUFA; hempseed oil; tocopherols; natural preservatives; oxidative stability; lipid oxidation; storage; ω-3PUFA; heating; GLA
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.14817

Oxidative stability of hempseed and soybean oils, was evaluated after heating at 180 °C, followed by a subsequent 14‐day storage at 38 °C. Natural plant extracts (Rosemary, Sage, and Thyme) were added to oils, to evaluate the carry‐over stabilizing potential. Heated oils exhibited a relatively faster (P < 0.05) onset of lipid oxidation, as depicted by the analysis of the peroxides and aldehydes formed during the lipid oxidation process, with hempseed oil being more susceptible to lipid oxidation than soybean oil. There were notable losses in ω‐3 PUFA and ω−6‐GLA during storage of heat treated hempseed oil (P < 0.05). Moreover, peroxide values measured from hempseed oil remained low after high‐temperature heating but progressed at a relatively greater rate than that observed in soybean during storage (P < 0.05). The addition of different plant extracts to oils did not prevent oxidation due to heating, but effectively inhibited the generation of hydroperoxides during subsequent storage (P < 0.05). This stabilizing effect was attributed to retention of tocopherols, in particular, γ‐tocopherol.
Practical Application
This research demonstrates the use of plant extracts like rosemary, sage and thyme, for improving the shelf‐life and nutritional stability of hempseed and soybean oil. We demonstrate the deterioration of fatty acid profiles and vitamin E levels in the oil on heating and subsequent storage, and show the efficacy of using plant extracts in slowing down these deteriorations. This research will be applicable in food industries using or producing oils for use in food during cooking, and also as dressing on already processed food products.