Behaviour of polydiacetylene vesicles under different conditions of temperature, pH and chemical components of milk

• Cristiane Patrícia de Oliveira^a, , 
• Nilda de Fátima Ferreira Soares^b, , , 
• Edimar Aparecida Filomeno Fontes^b, , 
• Taíla Veloso de Oliveira^b, , 
• Antônio Manoel Maradini Filho^b, 

• Received 21 February 2012. Revised 17 May 2012. Accepted 20 May 2012. Available online 28 May 2012.
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Abstract

Blue polydiacetylene vesicles were studied with regard to their behaviour under variations in storage temperature, heating, potentiometric titration and in the presence of chemical components of milk, to evaluate their application as a sensor in the food industry. Vesicles were prepared using 10,12-pentacosadienoic acid (PCDA)/1,2- dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC). Their changes were monitored using UV-Vis absorption. Temperatures not exceeding 25 °C did not cause colour change in PCDA/DMPC vesicles for a period of up to 60 days of storage. Heating for 10 minutes at 60 and 90 °C, exposure to pH higher than 9.0 and the simulant solutions of the whey proteins, β-lactoglobulin and α-lactalbumin, promoted colour change from blue to red for the vesicles studied. The effects of routine factors on the characteristics and stability of polydiacetylene vesicles is important in defining the parameters related to their application as a sensor for the food industry.