Physicochemical properties and application in film preparation of prolamin from distiller's grains

Summary Prolamin of sorghum‐based distiller's grains was extracted and its physicochemical properties were further determined. The prolamin was found to be rich in acidic amino acids, resulting in an isoelectric point of pH 4.0. High content of α‐helix structure endowed the protein good thermostability with a denaturation of 123.47 °C. The prolamin was resistant to pepsin but susceptible to trypsin in vitro digestion. The nutritional evaluation score was low and the protein does not belong to a good source of food protein due to the low digestion and lack of essential amino acids. The prolamin exhibited low water‐holding capacity, oil‐holding capacity, foam properties, and emulsifying properties. Moreover, the protein possessed good film‐forming properties, and the characteristics of high temperature resistance, low water‐holding capacity and oil‐holding capacity of prolamin can endow the protein film with excellent properties of water blocking, oil blocking, and high thermal stability.