Lucky dip of interesting research results (Part 4)
admin | November 12, 2010A real mixed bag this lot. As always remember, ‘resutls may vary’
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The optimum temperature for pollen germination in 4 varieites was 20-25C and lowest at 15C. Koroneiki pollen germination was reduced under conditions at 30C and low humidity.
Koubouris et al. (2009) Impact of temperature on olive pollen performance in relation to relative humidity and genotype. Environmental and Experimental Botany. 67, 209-214.
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After vertical centrifugation using 0.25L water/kg of oily must, dissolved oxygen increased 4.5 fold (cv before centrifugation) which resulted in increased peroxide values. Total phenols and fatty acid profiles were unchanged.
Masella et al. (2009) Influence of vertical centrifugation on extra virgin olive oil quality. J. Am. Oil Chem. Society, 86, 1137-1140.
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Picual oil made from fruit laying on the ground did not exceed the IOC limit for FFA until around day 52. The IOC limit for peroxide was not exceeded even after 90 days.
Allouche et al. (2009) Fruit quality and olive leaf and stone addition affect Picual virgin olive oil triterpenic content. J. Ag. Food Chem. 57, 8998-9001.
Comment: This result was not the major aim of the research but was interesting nevertheless. May go someway to explaining the ridiculously high FFA and peroxide limits set by the IOC for extra virgin grade.
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Madrid consumers are willing to pay between 11 and 13% extra for organic EVOO over conventional EVOO depending on their demographic.
Bernabea et al. (2009) Oporunidades comerciales para el aceite de olive de Casteilla-La Mancha. Grasas y Aceites 60(5), 525-533 (in Spanish)
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Hammer milling produced oils with more polyphenols compared with stone milling. Microscopy showed that hammer milling tended to slice the olive cells open while stone milling caused a significant amount of cell flattening via compression.
Veillet et al. (2009) Chemical changes in virgin olive oils as a function of crushing systems: Stone mill and hammer crusher. C.R. Chimie, 12, 895-904.
Comment: An unreplicated study, but the results were in line with other studies. The scanning electron microscope images of the olive cells just after milling showing the release of oil droplets from the cells are really cool!
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The bitter phenolic oleoropin decreased during ripening of 6 Italian cultivars. Coratina contained more than did Leccino at all ripeness stages.
Ranalli et al. (2009) Variations of iridoid oleuropein in Italian olive varieties during growth and maturation. Eur. J. Lipid Sci. Technol. 2009, 111, 678–687.