Storage stability of plain stirred whole milk yoghurt (3.7% fat) packed in polylactic acid and polystyrene

Plastic packaging used for dairy products challenges researchers and producers. Therefore, polylactic acid (PLA) was analysed as a sustainable packaging material for plain stirred yoghurt. PLA and polystyrene (PS) cups were filled and sealed with transparent PLA film or aluminium lids respectively and stored for 42 days with and without light exposure (2.4 +/- 0.4 degrees C; 78.8 +/- 5.4% relative humidity). Influence of packaging on yoghurt quality was evaluated by measurement of pH, water content, viscosity, colour, headspace oxygen, and peroxide value, and by sensory and microbial analyses. Water content and vis-cosity remained stable during storage. A slight decrease of oxygen concentration was observed in the headspace of PLA in comparison with PS. Scanning electron microscopic images revealed that no material changes could be attributed to yoghurt. Results indicate that opaque packaging like PLA can be used for yoghurt to avoid light-induced colour changes, vitamin loss and lipid oxidation. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The research on using polylactic acid (PLA) as a packaging material for plain stirred yogurt shows that opaque packaging like PLA can be used to maintain stable water content and viscosity of yogurt while avoiding light-induced color changes, vitamin loss, and lipid oxidation.