engleski

The effect of plant extract addition on oxidative stability of different oils

Over the last decade scientific studies on aromatization of plant-derived oils and potential prolongation of their shelf-life by the addition of natural plant extracts have increased exponentially. This study investigated the chemical composition and oxidative stability of cold pressed and unrefined oils of hemp seed, flaxseed, sesame, and sunflower, as well as the effect of plant extract addition (balm, rosemary, winter savory, oregano, and lavender) on its stability. The oxidative stability of oils (3 g) without or with plant water extract additon (100 µL) was tested by Rancimat apparatus (20 L/h, 120°C). The fatty acid profile of oils was analysed by gas chromatograph with FID detection Linoleic acid was the dominant fatty acid in all oils (range from 45 to 65%) except in flaxseed oil where high content of linolenic acid (50%) was detected. Among tested oils, sesame oil had the longest stability time (3.28 h) while most susceptible to oxidation was flax oil. The addition of balm, savory and oregano extracts in hemp seed and flax oil resulted with increased rate of their oxidation while in all other cases time of oil stability was prolonged. Especially good results were detected for lemon balm extract in case of sesame and sunflower oils, where 33 and 48% longer induction time was obtained.

plant extracts ; oil oxidative stability ; Rancimat ; fatty acid profile

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