New research at the University of Vienna! Poly (lactic acid) (PLA) can be used as a packaging material for edible oil instead of PET
Bottles made of bioplastics PLA can protect edible oil from oxidative deterioration (rancidity), and the degree is similar to PET bottles. In addition, there are fewer substances that damage the taste and smell. This is the result of a study recently published in the magazine "Food Packaging and Shelf Life" by researchers from the University of Vienna led by Marc Pigniter of the School of Chemistry of the University of Vienna.
In order to keep healthy edible oil with high proportion of unsaturated fatty acids fresh for a long time, the bottle material is very important. Due to its material characteristics and low cost, PET bottles are usually the first choice for this purpose. However, PET (polyethylene terephthalate) is difficult to be biodegradable and has been retained in nature for up to 2000 years. For example, the global plastic production is close to 400 million tons (2021). Only one third of the plastic waste in Austria is being recycled, while one quarter of the plastic waste finally enters the landfill sites around the EU. Therefore, in 2022, the European Commission called for the formulation of new regulations within the EU to transition to bio-based, biodegradable and compostable plastics. The research team led by Marc Pigniter, a food analyst at the Institute of Physiology and Chemistry of the University of Vienna, is studying a group of substances in depth.
The research team is studying whether the bioplastics bottles made of PLA can be used to store edible oil. Given the global production of about 200 million tons of edible oil, this will have a decisive advantage in terms of sustainability and environmental compatibility.
In a 56-day storage study, two renewable bottle materials, polylactic acid (PLA) and biological polyethylene (Green-PE), were compared with traditional plastics composed of raw and recycled polyethylene terephthalate (PET, r-PET) and ordinary polyethylene (PE). The effects of different packaging materials on the oxidation stability and shelf life of sunflower seed oil were compared. The key is the production of oxidation products in oil caused by packaging, which is the cause of rancidity and bitterness. In addition, the compounds transferred from the bottle material to the oil were also analyzed.
The results of the storage study showed that the sunflower seed oil packed in PLA bottles showed similar results in terms of primary oxidation compounds, such as peroxide value, total hydroperoxides and hydroperoxide Z, E-conjugated dienes, as compared with the oil stored in r-PET and PET bottles. The formation of secondary lipid oxidation products (E) − 2-heptaldehyde and valeric acid in sunflower oil stored in PLA is not even as obvious as in r-PET or PET bottles. Therefore, PLA can be used as a renewable non-fossil packaging material for edible oil, because it can prevent the lipid oxidation of sunflower oil, and its degree is similar to r-PET and PET bottles.
In addition, compared with PET bottles, "inadvertent introduced substances" (NIAS) were not detected leaking into oil in PLA bottles.
All these evidences show that using PLA bottles to store edible oil may be a substitute for r-PET or PET, and providing oil without NIAS may be more acceptable to consumers. This study confirmed that PLA can be a reasonable substitute for traditional plastic packaging (such as PET for vegetable oil).
