A Sustainable Approach for the Use of Plant Proteins as Functional Ingredients in Dairy Alternatives

The increasing global demand for sustainable and health-promoting foods has positioned plant-based proteins as key components in the development of dairy alternatives. This review critically examines plant protein sources: legumes, cereals, pseudocereals, oilseeds, and nuts not merely by composition, but by their comparative suitability for specific dairy applications, evaluating protein quality using the Digestible Indispensable Amino Acid Score (DIAAS), digestibility, and source-specific antinutritional factors (phytates in cereals; tannins, trypsin inhibitors, and lectins in legumes and oilseeds) relative to milk-derived reference proteins. Structural determinants of functional performance particularly the relative proportion of 7S versus 11S globulin fractions are identified as a stronger predictor of emulsifying, foaming, and gelling behavior than protein source or purity alone, while extraction method emerges as a recurring confounding variable, since conventional alkaline and acid extraction routes measurably compromise the same structural integrity that governs functional performance. Conventional and innovative extraction technologies (ultrasound-, pulsed-electric-field-, deep-eutectic-solvent-, and enzyme-assisted extraction) are compared on this basis, alongside their trade-offs between yield, structural preservation, and industrial scalability. Regulatory constraints on dairy-product naming in the EU and beyond, and the competitive landscape of plant-based dairy manufacturers including a shift toward precision-fermentation and mycoprotein-based approaches, are also examined. This review further highlights a methodological limitation affecting the underlying evidence base: the absence of standardized functional-property assays across studies means that a meaningful share of reported "source-driven" variability may instead reflect protocol-driven inconsistency, a caveat that should inform how findings across this literature are compared. Collectively, this review provides an evidence-based, application-oriented framework for selecting and processing plant proteins to meet the specific nutritional, functional, and regulatory demands of dairy-alternative formulation.