Interfacial properties of poppy seed protein (Papaver somniferum L.) as an alternative protein source at oil/water interface: influence of pH on stability, morphology and rheology

This study was systematically investigated the bulk and interfacial rheological properties of the poppy seed proteins as new source of plant proteins for healthier diets. Results revealed that low molecular weight of proteins (> 15 kDa) might contribute to the emulsion stability. The droplet size increased inversely with protein band density in the 10–15 kDa range. The pH value of the most stable emulsion was pH 3.0. An increasing trend of emulsion activity was observed for decreasing pH values which perhaps could be attributed to an opening of protein conformational structures. The optical microscopy results showed that the decrease in pH resulted in a better storage stability as promoting the formation of a more uniform distribution and smaller oil droplets. We conclude that present study puts forth a major contribution to plant protein research by demonstrating its ability to make stable emulsion as a function of pH at the O/W interface.