Heat Treatment: A Strategy for Overcoming Challenges in Whole-Wheat Product Processing

Whole-wheat products offer significant health benefits due to their high contents of dietary fiber, vitamins, minerals, and bioactive compounds. However, challenges in their production and consumption persist. This review summarizes the following challenges: difficulties in bran breakage, microbial and mycotoxin contamination, pesticide residues, rancidity, inconsistent physical properties, poor physicochemical qualities and sensory attributes, and limited nutrient bioaccessibility. To overcome these challenges, researchers have proposed many strategies, among which heat treatment represents a widely studied strategy to address these issues. To better understand how heat treatments function, we introduce and analyze various methods, such as hot air, heat-moisture treatment (HMT), superheated steam, steaming, autoclaving, steam explosion, infrared heating, radio frequency (RF), ohmic heating, microwave, and extrusion, as well as the combination of multiple heat treatments or hybrid approaches with nonthermal methods. The results show that, the understanding of heat treatment mechanism is still insufficient, hindering further studies and applications, though these methods achieve promising results. Further efforts should prioritize combining diverse heat treatments or heat treatment with nonthermal methods. Future research should focus on the following areas: elucidating bran structure and sensory deterioration mechanisms, studying the heat-induced structural changes of mycotoxins and key components, and exploring synergistic combinations and process optimization.