Summary of interesting research results (Part 8)
admin | December 11, 2010Oil yields, polyphenols and colour depth were higher, and oils were clearer when made using Pectinex Ultra SP-L and Pectinase 1.6021 enzymes compared with untreated controls. Pectinex treatment was more effective than Pectinase in increased polyphenols in Koroneiki oils.
Najafian et al. (2009) Aqueous extraction of virgin olive oil using industrial enzymes. Food Research International 42, 171-175.
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Potted mature Koroneiki and Mastoidis trees subjected to increasingly salty irrigation produced fruit with higher moisture and lower oil content. Increasing salinity produced oils with higher phenolics and lower oleic acid levels.
Stefanoudaki et al. (2009) Olive oil qualitative parameters after orchard irrigation with saline water. Journal of Agricultural and Food Chemistry 57, 1421-1425.
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The phenolic oleocanthal induced pungency that was mostly perceived at the back of the throat and was most intense at 15 seconds after eating. Significant variation between individuals was observed.
Cicerale et al. (2009) Sensory characterization of the irritant properties of Oleocanthal, a natural anti-inflammatory agent in extra virgin olive oils. Chemical Senses 34, 333-339.
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A 10 yr study of 4856 adults found an association between oleic acid intake and reduced risk of depression in women. No association between intake and incidence of depression was observed in men.
Wolf et al. (2009) Dietary linoleic and oleic acids in relation to severe depressed mood: 10 years follow-up of a national cohort. Progress in Neuro-psychopharmacology and Biological Psychiatry, 33, 972-977.
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Irrigating at 25% of that required to meet evapotranspiration throughout the entire growing season and only during midsummer both reduced per hectare oil yield by around 15%. Irrigating up to evapotranspiration cost 1 megalitre of water for each extra 10kg of oil produced.
Iniesta et al. (2009) The effects of regulated and continuous deficit irrigation on the water use, growth and yield of olive trees. European Journal of Agronomy 30, 258-265.
Comment: In Australia water is currently being traded on the open market at around $40 per megalitre – so irrigating to this extent would increase the cost of production by a massive $4 (EUR 3) per kg – aka more than EVOO is currently worth.
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Destoning olives prior to crushing produced oils with higher polyphenols and tocopherol than those made with whole olives. The addition of cytolase enzyme further increased these components while talc addition during malaxation had little effect.
Ranalli et al. (2009) Evaluation of functional phytchemicals in destoned virgin olive oil. Food Bioprocess and Technology 2, 322-327.
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The blue tasting glasses used in EVOO assessment do not effectively mask the colour of olive oils. Between glass variation was significant and higher than the variation in colour of the different oils in the same glass.
Melgosa et al. (2009) Color measurements in blue-tinted cups for virgin-olive-oil tasting. J. Americal Oil Chemists Society, 86, 627-636. Comment: I’ve never been convinced of the need to cover the colour up anyway. Recite after me “green oils aren’t always herbaceous and yellow oils aren’t always ripe” Got it? Pretty straightforward after all. 🙂
Re the color of the tasting glasses: as I’ve said before, sometimes the unconscious brain is not quite listening to what the rational mind knows 😉 . There’s a substantial corpus of psych. research that shows pretty clearly that very subtle things *do* influence the judgements of real adults, even for things with which they’re familiar, like how the (falsely) stated cost or appellation of a wine, or brand of a soda or cigarette, affects people’s reported taste of either, or how the size of a serving of food (or the vessel in which it’s served) affects how much one eats of it, or things like trivial gifts (pens, pads of paper) of no particular monetary value still favorably influence medical students’ perception of a drug. We bring our whole brains to bear onto any act of discrimination that we perform, and our brains spit out a single judgement on what what is supposed to be a very narrowly-defined characteristic, not just the parts we ‘know’ are relevant or ‘appropriate.’
Hi again Richard,
A followup on the color question: in a recent study, summarized in the University’s press release:
The researchers manipulated orange juice by changing color (with food coloring), sweetness (with sugar), or by labeling the cups with brand and quality information. They found that though brand name influenced people’s preferences for one cup of juice over another, labeling one cup a premium brand and the other an inexpensive store brand had no effect on perceptions of taste.
In contrast, the tint of the orange juice had a huge effect on the tasters’ perceptions of taste. As the authors put it: “Color dominated taste.”
Given two cups of the same Tropicana orange juice, with one cup darkened with food coloring, the members of the researcher’s sample group perceived differences in taste that did not exist. However, when given two cups of orange juice that were the same color, with one cup sweetened with sugar, the same people failed to perceive taste differences.
"It seems unlikely that our consumers deliberately eschewed taste for color as a basis for discrimination,” write the authors. “Moreover, our consumers succumbed to the influence of color but were less influenced by the powerful lure of brand and price information.”
Another study finds that (oh, horrors!) that "AMBIENT LIGHTING MODIFIES THE [perceived] FLAVOR OF WINE”.
Hi again Richard,
Sorry: the color thing again:
54 subjects were invited to a series of two experiments in which they had to comparatively describe a real red wine and a real white wine. Some days later the same subjects had to comparatively describe, in their own words, the same white wine and a red-[food]-coloured white wine. … What in fact is in the glasses during the first experiment a glass of red wine and a glass of white wine whereas during the second there were two glasses of identical white wine, except from the point of view of colour. …
The real red wine was described from an olfactory and gustative point of view in classical red wine terms. Whereas the white wine was described in usual white wine terms during this first experiment. In a similar fashion the white wine of the second experiment was described with white wine terms, this opposed to the same white wine coloured red. The Chi test carried out on the descriptions permitted the affirmation that the subjects described the two wines of the colour red in an identical fashion whereas one of them presented the aromas of a white wine. On the contrary the presence of the colour red in the white wine reversed the description of its descriptive parameters.
In this experiment the perception of fragrance and taste conformed therefore to colour. This phenomena has been the object of an abundant literature (Maga, 1974, Dubose, 1980, Davis, 1981, Johnson, 1982, Zellner and Kautz, 1990 in the food processing field; and in the wine field (André, 1970, Williams, 1984). The principal conclusions of this work have also been practical: colourless syrups have disappeared from the market. [Tee hee! -M]
The obvious limitation here is that everyone knows that red wine is actually different from white, and known to be so, whereas most tasters should know, and could be taught, that “green oils aren’t always herbaceous and yellow oils aren’t always ripe”. But sensory experience is a gestalt, created in the brain from the multiple neurological inputs, including present sensory stimuli, memory, and cognitive elements, which can’t be segregated fully by an act of will; and, we’re a dominantly-visual species. Maybe dogs could be trained to let their tastebuds override their eyes, but I’m skeptical that humans can do so.
Oops– the reference:
Brochet F.Chemical Object Representation In The Field Of Consciousness. 2001; Application presented for the grand prix of the Académie Amorim following work carried out towards a doctorate from the Faculty of Oenology, General Oenology Laboratory, 351 Cours de la Libération, 33405 Talence Cedex.