Product description & requirements
Olive oil is a natural product that is sensitive to oxygen and light. The oxidation of EVOO can occur principally in two ways: auto-oxidation and photo-oxidation. Oxygen in the air and dissolved in EVOO is not by itself very destructive; the presence of oxygen AND light is however a bad combination because of destructive oxidation chain reactions which occur. Therefore, PET bottles need to be colored with a masterbatch that reduces the amount of UV light passing through its wall. The use of oxygen scavengers will reduce the permeation of oxygen into the bottle and consequently into the EVOO. Also UV-blocking additive could help.
Target was to develop an aesthetically appealing plastic bottle comparable to glass and that would perform well in terms of mechanical and barrier (light and oxygen) properties, to obtain an optimum shelf-life.
Development & challenges
For EVOO the European Official limit for the amount of oxygen present is 20meq/kg. The main challenge at this point is to find the optimum color that gives the best protection against UV light.
EVOO becomes rancid with photo-oxidation. This spectrum shows that EVOO highly absorbs in the UV range once oxidation has occurred.
Fig 1 - EVOO becomes rancid with photo-oxidation.
(Source: Shimadzu, Azom.com)
Results & packaging features
PET bottles for EVOO must fulfill important requirements such as good aesthetic appearance both in brilliance and transparency, as well as good mechanical, thermal and chemical resistance.
With the right green/amber color, the PET bottle can reach the requested shelf-life.
Fig 2 - Wavelength (nm) vs light absorbance (%).
Yellow = PET clear;
Aqua = PET green;
Brown = olive green/brown
Filling process description
Flextronic W: Electronic Weight Filler
Extremely simple, clean and fast “no contact” valve, with a 3 position membrane valve featuring double speed.
This solution guarantees high flow performace, ideal for edible oil. Weight filling technology is considered the most reliable, clean and efficient system for filling bottles with edible oil.
It is particularly appreciated for the fact that it avoids overfill: by measuring the weight directly in the container (net weight), it takes into account the changes in the tare as well as in the temperature or nature of the oil and adapts to intrinsic changes of the product during the production cycle.
Fig 3 - 3D rendering of the Flextronic W filling valve
SIPA's products include a wide range of solutions for the manufacture of preforms and containers,
filling, process and secondary packaging, able to satisfy all the needs of the mineral water
market in terms of bottle shapes, products and productivity.