Does oxygen in the headspace of the packaging container influence Olive Oil quality?

28/11/19: Extra Virgin Olive Oil is the oil obtained from fresh olive fruit in perfect condition picked at optimal maturation with the utmost care and attention to the mechanical extraction processing to achieve the oil.  Olive Oil is the only vegetable oil that can be consumed directly in its raw state and contains important healthful nutritional properties.

Extra Virgin Olive Oil carries a unique profile of healthful properties and warrants special care and attention to the packaging and storage to uphold the nutrition, flavour and colour attributes of the product.

The 4 enemies which create a deterioration of olive oil are Heat, Air, Light & Time (HALT) and thus reducing these elements can greatly prolong the shelf-life of Extra Virgin Olive Oil.  Although no one has control over time but heat, air and light are at the centre of attention.   Evaluating the exposure to light, temperature, oxygen headspace, natural antioxidant or phenol content and oxygen dissolved in extra virgin olive oil during the bottling process all affects the deterioration rate and shelf-life during storage.

Researchers at the University of Florida aimed to assess factors to reduce or control the O2 headspace concentration in the package and the influence on quality, shelf-life and favourable sensory characteristics of Extra Virgin Olive Oil.  Due to the gap in information concerning the optimum package headspace O2 concentration during storage, additional research was needed to highlight the potential benefits of reduced oxygen headspace packaging of Extra Virgin Olive Oil.

The study looked at:

  • Headspace volumes at 50 mL after placing the oil in jars in dark and clear glass containers.
  • Four different oxygen concentrations were applied to the oil samples 21% oxygen (control/
    normal atmosphere pressure); and 10% oxygen; 5% oxygen; and 2% oxygen (at atmosphere pressure).

Researchers noted “Low headspace oxygen concentration is important for maintaining quality and shelf-life of Extra Virgin Olive Oil and the findings at 2% and 5% headspace oxygen, in clear or dark glass containers, at 10 °C protects chemical indices beyond 12 months and total polyphenols were protected beyond 6 months as was chlorophyll in dark bottles and colour parameters were protected beyond 9 months”

In another study, it was suggested that the above findings could be extended even further with the use of modified atmosphere packaging.

Modified atmosphere packaging (MAP) is the removal and/or replacement of the atmosphere surrounding the product within packaging.  In passive MAP, package atmospheres are left to change dynamically based upon gas consumption/production by packaged products and permeation characteristics of packaging.   Active MAP uses systems to remove and/or replace atmospheres prior to sealing packages.  Vacuum and/or gas flush systems are examples of active MAP systems.

It was also found that low oxygen MAP offers an opportunity to improve the shelf life of extra virgin olive oil.

Furthermore, the control of the storage environment (i.e. light and temperature) likely increase the efficiency of MAP on EVOO quality and shelf-life.

Overall, low oxygen MAP technology appears viable for enhancing the shelf-life of EVOO during storage. Understanding how MAP technology influences EVOO quality and shelf-life will ultimately assist processors in improving the storage conditions for EVOO. Combining MAP technology and other factors such as packaging type, package headspace volume, and storage temperature are also likely to present potential advantages for EVOO storage.

This research is interesting because it highlights possibly overlooked or under-appreciated factors that can influence quality parameters within the extra virgin olive oil.  Enabling to decrease the factors contributing to quality decline can have a beneficial effect for an extended time for the sale of the product.  It is also noted that no matter the type of packaging if temperatures are elevated during storage of the product in the container or at the retailer, will greatly contribute to a reduction in shelf life.

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Influence of Headspace Oxygen on Quality and Shelf Life of Extra Virgin Olive Oil During Storage

Abstract

This study evaluated the impact of low O2 headspace in clear and dark containers at different storage temperatures (10 °C and 28 °C) on the quality and shelf life of extra virgin olive oil (EVOO). Bottle headspace was controlled at four different O2 concentrations 2, 5, 10, and 21%. Quality parameters were determined after 3, 6, 9, and 12 months storage: free fatty acids, peroxide value, absorption coefficients K270 and K230, total polyphenols, chlorophyll content, oxidative stability index, and color. Results show low headspace oxygen levels of 2 and 5%, significantly increased EVOO shelf life stored in dark and clear bottles at 10 °C. While the improvement in EVOO shelf-life was less when stored at 28 °C. No significant differences occurred between EVOO samples packaged at 10 and 21% headspace O2 concentrations in clear bottles stored at 28 °C while significant differences were observed with 2 and 5% headspace O2 concentrations. These results suggest that it is important to minimize headspace oxygen in packages of extra virgin olive oil.

Authors:  Basheer M.IqdiamaBruce AWeltbReneeGoodrich-SchneideraCharles ASimsaGeorge L.BakerIVaMaurice R.Marshalla

  • a Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, United States
  • b Agricultural & Biological Engineering Department, University of Florida, Gainesville, FL 32611, United States

Read the full study at Food Packaging & Shelf Life

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