Developments in Traditional Indian Heat-Desiccated Milk Products: Process Intensification, Quality Transformations, Shelf-Life Technologies and Research Priorities

Abstract

Traditional Indian heat-desiccated milk products are a technologically distinctive family in which evaporation, surface heating, agitation and product working jointly determine concentration, structure, flavour and storage stability. Khoa and its variants form the principal intermediate for peda, burfi, kalakand and milk cake, whereas rabri and basundi are directly concentrated products with their own structural signatures. This critical narrative review evaluates developments in the field with emphasis on process intensification, heat-induced physicochemical transformations, product-specific scale-up, reformulation, packaging, preservation, authenticity and translation to industrial practice. Literature published from January 2000 to 30 June 2026 was examined, with earlier foundational evidence retained when necessary. The evidence indicates that scraped-surface heat exchangers, controlled vats, ohmic heating and mechanised forming can reduce dependence on highly manual operations and improve throughput or process control, but equivalence to traditional sensory quality is not automatic because thermal history and shear are integral to product identity. Heat concentration promotes desirable cooked and caramelised notes while simultaneously driving protein denaturation, protein–protein interactions, Maillard chemistry, lipid deterioration and loss of available lysine; raw-milk acidity and neutralisation can intensify several undesirable changes. Packaging interventions, particularly vacuum and product-specific modified atmospheres, can materially extend shelf life under controlled conditions, while essential oils, microwave thermisation and active antimicrobial films offer additional hurdle options. Yet most studies remain laboratory or pilot scale, use narrow sensory panels, and rarely integrate distribution abuse, economic performance, life-cycle burdens or inter-site reproducibility. Sugar and lactose modification further demonstrate that reformulation changes the physical matrix, not merely nutritional composition. The field is therefore moving from empirical batch craftsmanship towards measurable process–structure–quality relationships, but robust industrial validation remains limited. Future progress requires product-specific process fingerprints, validated sensors and control strategies, larger consumer studies, challenge testing, harmonised quality metrics, authenticity surveillance, and comparative energy, cost and environmental assessment.