Novel Insights into Milk Coffee Products: Component Interactions, Innovative Processing, and Healthier Product Features

Milk coffee is a composite beverage in which interactions among dairy proteins, lipids, and coffee polyphenols govern flavor, texture, and stability. This review synthesizes recent research to guide formulation and processing, covering conventional Ultra-high temperature sterilization (UHT) and innovative routes including blending-after-sterilization (BAS), high-pressure homogenization (HPH), ultrasound/pulsed electric field (PEF)/cold plasma (CP), microencapsulation, and plant-based matrices. Key findings show that non-covalent protein–polyphenol complexes and interfacial partitioning at fat-globule membranes control volatile retention, astringency, droplet structure, and phenolic bioaccessibility; appropriate fat levels and HPH refine microstructure; BAS better preserves aroma; and matrix or decaffeination choices modulate antioxidant capacity. Guided by these insights, we propose a concise “process–activity–stability” framework linking parameters to functionality and shelf life to accelerate the development of high-quality, nutritious, enjoyable, and more sustainable milk coffee products.