A Lucky Dip of Relevent Research Results for EVOO Producers and (sometimes) Consumers (Part 1)
admin | October 29, 2010Around 40-50 scientific papers are published every week on olive oil. Typically 2/3rs will be related to the health aspects of olive oil and the remaining on olive growing, olive oil extraction and storage. Articles on waste treatment (zzzzz) also appear very regularly on the lists. And every now and then something even comes along on the use of olive oil in the kitchen.
Here are a few that I’ve read (yep from start to finish) and have distilled the interesting and relevent results into a short paragraph;. The link to the authors summary is also given. Our summaries don’t always match as I sometimes choose to add some of the obscurer but (in my opinion) more interesting results that they squirrel away somewhere on page 10,
This is Part 1 – lots more to follow. It is a mixed bag of stuff – sometimes, but not always contradictory. But that’s the nature of scientific endeavour. Some will be from last Monday and a few oldies but goodies from a decade ago. However I have drawn the line at reading and summarising papers on olive sludge – important as it may be.
Storage on the Healthy Components of EVOO
Total polyphenols in extra virgin olive oils declined by between 43 and 73% over a 21 month period when stored in dark cold storage without any headspace. Alpha-tocopherol levels also decreased by between 12 and 23% while oleic acid level remained unchanged.
Gomez-Alfonso et al. (2007) Food Chemistry.
http://www.elsevier.com/wps/find/journaldescription.cws_home/405857/description#description
How the Olives are Crushed Affects Quality
Hammer crushing produced hotter olive pastes cv disk crushing. Hammer crushed oils had higher FFA, peroxide values and shorter induction times i.e shelf life.
Caponio and Catalano (2007) European Food Research and Technology. http://www.springerlink.com/content/a5h1nh6h4w13vd0m/
Effect of Processing Temperature on Olive Oil Quality
Malaxing at 35C produced oils with lower amounts of desirable herbaceous aromas, higher disagreeable fermentation aromas and higher peroxide values compared with oils made from the same paste but malaxed at less than 30C.
Ranalli et al. (2001) European Journal of Lipid Science and Technology http://www3.interscience.wiley.com/cgi-bin/abstract/79503318/ABSTRACT
What happens if you make oil from olives that have been frozen by frost
Severely frosted olives produced olive oils with no bitterness and reduced pungency due to a reduction in polyphenol level. An increase in the vanillin content of the frosted oils probably accounted for the increased in perceived sweetness of the frosted oils. Frosted oils had a lower shelf life. (That is, you get flat lifeless oils that don’t taste like olive oil – rg).
Morello et al. (2003) Food Chemistry.
http://www.elsevier.com/wps/find/journaldescription.cws_home/405857/description#description
A rare clinical trial on olive oil and health
The role of polyphenols in the healthfulness of EV oil was investigated in a clinical setting. A high pp oil (330ppm) was blended with a refined oil with similar fatty acid profile to produce low, medium and high pp oils. Eating 25ml of EV olive oil over a 3 week period increased the (good) high density lipoproteins, and reduced the (bad) oxidised low density lipoproteins. These changes were strongest in oils highest in polyphenol level.
Covas et al. (2006) Annals of Internal Medicine,
http://www.annals.org/cgi/content/abstract/145/5/333
Eating olive oil and DNA oxidation
Eating 25mls of olive oil over a three week period was shown to reduce DNA oxidation (a cancer trigger) in healthy males by 13%. The size of the decline was unrelated to the polyphenol level of the oil, suggesting that components other than polyphenols are responsible.
Machowetz et al. (2007) FASEB Journal
http://www.fasebj.org/cgi/content/abstract/21/1/45
Thank you for doing this, Richard! Unfortunately, only Springerliink seems to want the rabble like me to read the papers in full. I am especially interested in that malaxation temperature study… I’ll get it somehow. Some days I really miss being at the UC. Other days, not so much.
Cheers,
Alexandra
Hi Alexandra – You could try emailing the corresponding author and ask for a copy. The publishers allow a reasonable number of copies to be freely distributed by the authors. The authors are usually very obliging as well. The hardest part is often finding their email address, but the abstracts provided by the publishers is a good place to start.
Richard