The hydrogel formed by lentinan, a β-glucan extracted from the edible waste portion of shiitake mushrooms (Lentinula edodes), was investigated using dynamic viscoelastic measurements to determine whether it is a true gel. Furthermore, we analyzed the structural changes in the lentinan associated with gelation using NMR. Results from dynamic viscoelastic measurements suggested that structural changes in the lentinan occurred around 6°C during cooling, and that a true gel formed at temperatures below 6°C. This gel was similar to the hydrogels of scleroglucan, a β-(1,6)-branched β-(1,3)-glucan, and β-glucan derived from Sparassis crispa that we previously reported. Based on NMR results, the lentinan in this study was considered to have two β-(1→6)-linked glucose side chains for every five glucose units in the main chain. The NOESY measurement results suggested changes in side-chain orientation, indicating that the gel formed through the partial association of triple helices with reduced steric hindrance in the side chains.

This review presents a theoretical framework for the control of food texture and mouthfeel by shifting the focus from fat content adjustment to the design of interfacial properties and the spatial distribution of oil droplets through the use of hydrocolloids. The paper describes two hierarchical approaches: macro- and micro-level structural design. At the macro level, emulsion-filled gels are used to control bulk mechanical properties. By selecting appropriate emulsifiers, oil droplets can function as either active or passive fillers, thereby influencing the elasticity, chewiness, and breakdown behavior of the food matrix. At the micro level, oil droplets stabilized by soft polysaccharide microgels are employed to modulate oral tribological behavior. These microgels exhibit enzyme responsiveness; their degradation by salivary amylase during mastication induces the gradual release of oil, contributing to the perception of smoothness and creaminess over time. Finally, the review proposes a “nested structure” that integrates both approaches. This hierarchical design allows independent control of bulk elasticity and interfacial lubrication, providing a strategy to enhance desirable sensory attributes associated with fats without relying solely on fat content.