Green Tea Extract Enhances the Oxidative Stability of DHA-Rich Oil.

Caroline Waingeh Nain,Melissa Page,Gwennaëlle Berdal,Phan Thi Phuong Thao,Marine Buchet,Eric Mignolet,Yvan Larondelle

doi:10.3390/antiox10060982

Caroline Waingeh Nain, Melissa Page + Show 5 more

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https://doi.org/10.3390/antiox10060982

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Abstract

Docosahexaenoic acid (DHA) is one of the most important omega-3 polyunsaturated fatty acids, with proven health-promoting properties. However, oils with a very high content in DHA (DHAO) are extremely susceptible to oxidation, which affects shelf stability and limits incorporation in food products. Green tea extracts (GTE) are potential candidates for the protection of these oils, but their use in such oils has not been previously reported. This study investigated the effect of GTE (160 ppm, 400 ppm, 1000 ppm) and α-tocopherol (80 ppm, 200 ppm, 500 ppm) on the oxidative stability of a DHAO over a 9-week storage at 30 °C. The oxidative status was monitored during storage by the measurement of peroxide value (PV) and p-anisidine value (p-AV). Changes in eicosapentaenoic acid (EPA) and DHA content, as well as in catechins and tocopherol contents, were also evaluated. The addition of GTE enhanced the oxidative stability of DHAO by reducing the formation of peroxides and secondary oxidation products, whereas α-tocopherol had no significant effect on the PV of oil during storage but led to a significantly higher p-AV. The EPA and DHA content of DHAO was stable in GTE-supplemented samples whereas a decrease was observed in the control and α-tocopherol-supplemented samples. GTE also delayed the degradation of tocopherols initially present in the oil, while catechins resulting from the addition of GTE decreased progressively during the storage period.

Highlights

Docosahexaenoic acid (DHA, C22:6n-3) is a long chain omega-3 fatty acid and an essential component of a healthy diet
The DHA-rich oils (DHAO) had a polyunsaturated fatty acid (PUFA) content of 873 mg/g corresponding to 99% of total fatty acids in the oil, with the major fatty acid being DHA (626.7 mg/g = 71.1% of total fatty acids), followed by eicosapentaenoic acid (EPA) (149.3 mg/g = 16.9% of total fatty acids) and omega-3 docosapentaenoic acid (54.7 mg/g = 6.2% of total fatty acids)
The oil had a good oxidative status with a peroxide value (PV) of 2 meq O2 /Kg and a p-anisidine value (p-AV) of 5.2, which complied with the PV limit of 5 meq O2 /Kg oil and the p-AV limit of 20 established by the Global Organization for EPA and DHA Omega-3s (GOED) and by the Codex Alimentarius [5,43]

Summary

Introduction

Docosahexaenoic acid (DHA, C22:6n-3) is a long chain omega-3 fatty acid and an essential component of a healthy diet. Its consumption has been associated with a decrease in the risk of cardiovascular and inflammatory diseases, cancer and neurological disorders, among others [1,2]. DHA can be produced endogenously from alpha-linolenic acid (C18:3n3) by humans but the rate of biosynthesis is low and insufficient to meet physiological demands [3]. Dietary sources are required to meet the recommended daily intake of 250 mg DHA/day set for adults by the French Food Safety Agency (AFSSA) [4]. The traditional sources of long-chain omega-3 fatty acids, namely DHA and eicosapentaenoic acid (EPA, C20:5n-3) in the diet are oily fish and seafoods, which are naturally rich in these fatty acids. Microalgae are a primary source of DHA in the marine ecosystem and in recent years, the cultivation of microalgae for oil production has emerged as a new source of DHA

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