Weibo Zhang

Drying significantly influences the quality of micellar casein (MC) powder. This study investigated the effects of three pre-freezing temperatures (−20 °C, −80 °C, and liquid nitrogen) prior to freeze drying on the structure and rennet-induced gelation properties of MC powder. The results showed that as the pretreatment temperature decreased, the degree of disruption to the secondary and tertiary protein structures was reduced, while the particle size gradually increased. In terms of rennet-induced gel properties, the untreated raw MC consistently outperformed all MC powder samples. Among the MC powders, the sample pre-frozen at −80 °C and then freeze-dried (FD-80) exhibited the highest gel strength and a relatively shorter rennet coagulation time. The observed microstructures of the rennet-induced gel were consistent with the rheological results, showing that samples with smaller particle sizes formed more regular and compact gel networks. In conclusion, the MC powder prepared via pre-freezing at −80 °C and then freeze-drying better preserved protein structure and demonstrated superior rennet-induced gel properties, which were closely related to particle size. This study provides theoretical insights for the application of MC powder in products such as cheese, processed cheese, and protein-fortified foods.

Maintaining the solubility of micellar casein (MC) powder during storage is a major practical challenge. This study investigated the effects of storage temperature (−20 to 37 °C) on solubility and structure of MC powder. Results showed that solubility of MC powder was well preserved at 4 °C and −20 °C over 30 d, whereas higher storage temperatures led to a marked decline. Correspondingly, particle size and stability of rehydrated solution from powders stored at lower temperatures remained unchanged but increased significantly at elevated temperatures, alongside visible precipitation. Structural analysis indicated that surface cross-linking and reduced porosity occurred during storage, resulting in decreased solubility, which were effectively suppressed at 4 °C and −20 °C. These findings demonstrate that refrigerated storage at 4 °C is sufficient to maintain the solubility of MC powder, with no clear additional advantage observed at −20 °C under the tested conditions. This work provides practical guidance for optimizing MC powder storage.

Sensory attributes are the primary factors in the food product evaluation. However, traditional thermal processing often compromises the sensory qualities of foods, prompting the exploration of nonthermal technologies that preserve sensory attributes. Among emerging approaches, magnetic field (MF) treatment offers significant advantages in improving the sensory qualities of food products due to its noninvasive and residue‐free potential. Therefore, this review deeply focused on the effectiveness of MF treatment on the sensory quality, particularly the flavor profile, texture properties, and coloration. MF has shown promise in improving flavor attributes by reducing degradation, modulating enzyme activity, and preserving volatile compounds; Concerning texture properties, MF contributes to delaying softening, modulating protein structure, and forming smaller ice crystals, thereby maintaining tissue integrity and improving texture properties; In terms of color, MF can inhibit enzymatic browning, modulate protein structure, and reduce respiration rates, enabling coloration retention and achieving more fresh‐like qualities. In addition, outlining key challenges and future perspective were also discussed. Overall, MF interacts with food matrices by primarily modulating enzyme activity, protein conformation, and water behavior, influencing flavor, texture, and color profiles. This highlights that MF represents a promising nonthermal strategy for improving sensory quality in minimally processed food products.

Human serum albumin (HSA) plays an indispensable role as a carrier of endogenous and exogenous substances in vivo. The efficiency of endocytosis determines the transport capacity. However, the potential for enhancing the efficiency of HSA endocytosis remains largely unknown. This research represented a substantial advancement, revealing that Fe²⁺ markedly increased HSA endocytosis. Moreover, Fe²⁺ facilitated the endocytosis and transport of HSA in vivo. The enhancement in HSA uptake facilitated by Fe²⁺ is markedly decreased following iron chelation, indicating a specific interaction between Fe²⁺ and HSA that promoted endocytosis. Moreover, the study elucidated that FcRn and caveolin regulated HSA endocytosis under normal conditions. Yet, in the presence of Fe²⁺, endocytosis shifted toward clathrin‐ and caveolin‐enriched membrane domains, requiring both divalent metal transporter 1 (DMT1) and FcRn for efficient process completion. Thereby a new pathway is discovered for Fe²⁺‐dependent HSA endocytosis involving DMT1 and clathrin. This findings highlighted the crucial role of iron in enhancing HSA endocytosis and transport, establishing Fe²⁺ as a vital endocytic enhancer that required binding to HSA to substantially improve its uptake. This insight into the mechanism of HSA endocytosis not only expands the understanding of protein transport but also opens new avenues for therapeutic intervention.