Effect of pea milk preparation on the quality of non-dairy yoghurts

Neutral pea milk was prepared from direct soaking and blending of yellow peas by fresh water at 25 degrees C (Neu). Four different methods, including alkali water soaking at 25 degrees C (Alk), dry dehulling and alkali water soaking (Deh + Alk), boiling water blanching, wet dehulling and alkali water soaking (Bla + Alk), as well as boiling water blanching-dehulling and acid water soaking (Bla + Acid) were designed to treat peas. Pea milks were prepared by blending of the treated peas with water at 25 degrees C followed by centrifugation to remove solid residue. Using pea milk Neu as a reference, the properties and lactic acid bacteria fermentation features of pea milks as affected by pea treatment methods were investigated. Pea treatments resulted in changes in the contents and compositions of proteins, legumin/vicilin ratios, TCA-soluble nitrogen and volatile flavor components of pea milks. Compared with Neu, pea yoghurts prepared from Alk, Deh + Alk and Bla + Alk showed prominent improvements in gel hardness while pea yoghurt from Bla + Acid gave better flavor than others through volatile components analysis and sensory evaluations. On the other hand, different treatment decreased acid formation yield during lactic acid fermentation of pea milks.