Recent applications of high-humidity hot air impingement blanching (HHAIB) on plant materials: A review

The growing demand for advanced thermal blanching technologies has accelerated the search for methods that preserve food materials physicochemical, functional, and nutritional quality while addressing environmental and energy concerns. High humidity hot air impingement blanching (HHAIB) has emerged as a promising alternative to conventional wet blanching methods such as hot water and steam blanching, which are often associated with nutrient leaching, high water and energy consumption, and inconsistent quality outcomes. HHAIB combines high-velocity humid air with controlled thermal input, offering rapid and uniform heat transfer, enzyme inactivation, and superior retention of sensitive nutrients such as ascorbic acid and carotenoids. Recent studies highlight HHAIB effectiveness in improving product texture, microstructural integrity, color stability, and antioxidant capacity, while significantly reducing drying times and enhancing extraction yields. Additionally, HHAIB has been shown to support microbial reduction through moist heat and impingement-driven shear forces, providing a cleaner alternative without generating wastewater. This review synthesizes current findings on HHAIB operational mechanisms, including latent heat transfer, airflow dynamics, and enzyme-targeted thermal kinetics. It also compares HHAIB to emerging blanching technologies such as microwave, ohmic, infrared, vacuum steam pulsed, and radio frequency systems. Challenges related to scalability, energy efficiency, equipment design, and process standardization are discussed, along with future opportunities such as AI-driven process optimization, hybrid technology integration, and applications beyond food, such as biomaterial processing. Collectively, HHAIB offers a sustainable and highly adaptable solution for modern food processing systems, bridging the gap between high product quality and industrial scalability.