Almond proteins have potential utility in a range of food and beverages but it is not clear how pH affects protein structure and function. The behaviour of almond protein isolate was examined under conditions of neutral and acidic pH (pH 7 and 4). The isolate was highly soluble (70-80%) at either pH. An increase in acidity lead to protein unfolding, an increase in random coil structure and the appearance of lower molecular weight proteins due to acidic hydrolysis. These structural changes at pH 4 increased the capacity for foam formation and foam stability, increased viscosity and led to concentration and age dependent thickening. Gels, similar in strength but with distinct microstructures and properties were obtained following heating. At pH 7, a particulate type gel with an interconnected protein network was formed, while the gel at pH 4 had a dense continuous protein matrix. The gels differed in their susceptibility to...

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