High Moisture Extrusion of Soy Protein and Millet Flour Blends for Development of Texturized Protein Rich Foods

Abstract

Protein deficiency remains a significant public health issue in India, where plant-based diets dominate. These proteins, primarily derived from cereals and pulses, often lack essential amino acids, and their high carbohydrate content can lead to metabolic concerns. A shift towards environmentally sustainable solutions is crucial as global protein demand rises. This thesis generates the understanding of proteins functionality, high moisture extrusion process, blending principles and chemistry of fiber formation. Firstly, different proteins were characterized for their functionality, nutrition and rheological properties. A method was developed for simulating extrusion like conditions for better understanding of behaviour of raw materials/proteins. Soy protein isolate (SPI) was found to be superior in various properties which are important for extrusion. Further, extrusion process, system and product properties were studied and established the relationships by taking SPI as a model protein. These relationships help to create a wide range of texturally differentiated products. Incorporating millet flours up to 30% with SPI improved both visual and instrumental anisotropy and higher amino acid scores, making these products more comparable to real meat in terms of both texture and nutritional value. Additionally, fractionated millet components – fiber rich and starch rich fractions were studied to better understand the role of macromolecules (starch and dietary fibers). Starch rich fraction blend improved the textural profile and are comparable to the whole cut real meats. A method was developed to quantify the visual fiber through an image analysis technique. The research introduces a novel approach to using minimally processed plant fractions, highlighting millets as a key component in the future of sustainable, protein-rich, texturized plant-based foods.