Lucky Dip of Research Results (Part 3)
admin | November 6, 2010My interpretation of some interesting research, and the odd comment where I felt it necessary.. A couple of older papers for those interested in flavoured olive oils. I hope there is something of interest.
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Frying with extra virgin olive oil produced less airborne acrolein than either canola or vegetable (soybean) oil. Exposure to acrolein can aggravate childhood asthma and is a component of cigarette smoke which contributes to lung cancer risk. A significant amount of the free radical containing ozone was also generated by the deep frying process.
Seaman et al. (2009) Indoor acrolein emission and decay rates resulting from domestic cooking events. Atomspheric environment, 43, 6199-6204. –Comment – I wouldn’t recommend burning any oil regarless of what type -RG
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The pungency producing and anti-inflammatory phenolic Oleocanthal was resistant to degradation during prolonged heating falling by less than 16%. However, its biological activity fell by around a third when heated under the same conditions.
Cicerale et al. (2009) Influence of heat on biological activity and concentration of Oleocanthal – a natural anti-inflammatory agent in olive oil. Journal of Agricultural and Food Chemistry 57, 1326-1330.
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Oils were made from two varieties by malaxing at three temperatures (25, 35, 45C). Increasing temperature resulted in higher phenolics and induction time and no change in fatty acid profile. However, fruitiness tended to decline and burnt characters were detected in oils made at 45C.
Boselli et al. (2009) Are virgin olive oils obtained below 27oC better than those produced at higher temperatures? LWT- Food Science and Technology 42, 748-757. Comment: The results were based on the results of single batches of olives malaxed at the three temperatures. That is the trial was unreplicated.
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Oil from the variety Cornicabra was made on a production scale using three malaxation times (30, 60, 90 mins) and temperatures (2O, 28, 40oC). No effect on fatty acid profile was seen. Increasing temperature produced higher phenolics, carotene (yellow pigment) and wax content. Similar but less pronounced effects occurred with increasing malaxation time.
Inarejos-Garcia et al. (2009) Influence of malaxation conditions on virgin olive oil yield, overall quality and composition. European Food Research and Technology 228, 671-677. Comment: Despite the title, overall quality was not assessed as the oils were not subjected to sensory assessment.
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Infusing a low polyphenol EV olive oil both with dried oregano and dried rosemary increased the stability of the oil over 12 months as measured by peroxide value. Infusing the oil with garlic did not affect its stability. A panel of students preferred oils with medium to low levels of herbal flavour over the strongly flavoured oils.
Antoun and Tsimidoun (1997) Gourmet olive oils: Stability and consumer acceptance studies. Food Research International, 2, 131-136. Comment: An old paper, but very few studies have been conducted on flavoured oils so worth a review.
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Infusing olive oil both with rosemary and oregano resulted in increased chlorophyll and phenolics over the unflavoured base oil. The infused oils were more stable than the control when stored in the dark, but were substantially less stable when stored in the light. The reduced stability was likely due to chlorophyll being a catalyst for oxidation in the presence of light.
Damechki et al. (2001) Antioxidant and pro-oxidant factors in oregano and rosemary gourmet olive oils. Grasas y Aceites 52, 217-213.
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Co-crushing a batch of olives with dried garlic, cayenne, oregano, and fresh lemons, rosemary resulted in flavoured oils with much lower total polyphenol levels than the unflavoured control. However the antioxidant activity of the unflavoured oil at 9 months only exceeded that of the garlic flavoured oil.
Baiano et al. (2009) Changes in quality indices, phenolic content and antioxidant activity of flavored oils during storage. J. Am. Oil Chem. Society, 86, 1083-1092.