Oxidative stability of chia seed oil and flax seed oil and impact of rosemary (Rosmarinus officinalis L.) and garlic (Allium cepa L.) extracts on the prevention of lipid oxidation

Hyojik Jung,Sunghyeon Jung,Inhwan Kim,Jihyun Lee

doi:10.1186/s13765-020-00571-5

Hyojik Jung, Sunghyeon Jung + Show 2 more

Open Access

https://doi.org/10.1186/s13765-020-00571-5

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Abstract

Chia seed and flax seed oils are rich in polyunsaturated fatty acids, but are susceptible to oxidative deterioration. The aim of this study was to determine the oxidative stability of chia seed and flax seed oils and enhance the stability using rosemary or garlic extracts. During accelerated storage at 65 °C for 14 days, the antioxidant abilities of rosemary or garlic extracts were evaluated and compared with those of butylated hydroxy toluene, ascorbyl palmitate, and α-tocopherol using peroxide value, conjugated dienoic acids, free fatty acid, thiobarbituric acid value analysis. The profile of volatiles, fatty acid composition, and the tocopherol contents in the treated and/or untreated oils were also determined. Active ingredients of rosemary and garlic extracts were also determined. Rosemary extract was found to provide higher oxidative stability than garlic extract after 14 days in most assays (e.g., the CDA values of 4.8% for rosemary extract and 5.2% for garlic extract in chia seed oil). The contents of γ-tocopherol, linoleic acid, and α-linolenic acid were well retained in the functional oils treated with the two extracts. After accelerated storage, the content of the major odor-active volatiles varied based on the type of oil. Our findings show the potential of natural aromatic plant extracts with respect to improving the oxidative stability of functional oils.

Highlights

Flax (Linum usitatissimum) seeds and chia (Salvia hispanica) seeds are rich sources of α-linolenic acid
We investigated the changes in indicators of lipid oxidation, in chia seed and flax seed oils treated with extracts of rosemary or garlic bulb during accelerated storage at 65 °C for 14 days
Cold-pressed chia seed oil was purchased from Organic Pure Foods (Florida, USA), whereas cold-pressed flax seed oil was purchased from Alliga (Richmond, Canada)

Summary

Introduction

Flax (Linum usitatissimum) seeds and chia (Salvia hispanica) seeds are rich sources of α-linolenic acid. Omega-3 fatty acids (e.g., eicosapentaenoic acid (EPA), decosahexaenoic acid (DHA), α-linolenic acid)-rich diet is associated with the prevention of heart diseases. Flax seeds have been widely used as raw materials for production of functional oils. Chia seeds contain the highest proportion of α-linolenic acid (0.6 g/g of oil) among all known vegetable sources [3]. Chia seed oil edible oils with high polyunsaturated fatty acid content are susceptible to oxidative deterioration. Oxidation destroys the essential fatty acids (EFA) and may result in the production of toxic compounds and oxidized polymers. The lipid oxidation increases during thermal treatment. Destruction of EFA occurs at relatively high level during thermal treatment. When heated as mixture at 90 °C for 60 min, only 60% of linoleic acid (LA), 50% linolenic acid (LNA), 30% arachidonic acid (AA), and 20% docosahexaenoic acid

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