Recently, researchers from Innovative Team for Food Nutrition and Functional Foods at the Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (IFST-CAAS), successfully developed an alkaline-induced Dendrobium officinale polysaccharide-hemp seed protein (DOP-HSP) hydrogel system. DOP is well known for biological activities, such as relieving constipation and modulating immune function. HSP, contains all nine essential amino acids required by the human body and is highly digestible and absorbable. The combination of these two ingredients not only integrates nutrition and functionality but also provides a high-quality source of dietary protein and bioactive compounds for individuals with swallowing difficulties (dysphagia). On this basis, researchers systematically investigated the structural characteristics, molecular interaction mechanisms, and potential applications of the hydrogel system in dysphagia-targeted foods. The findings have been published in the international journal Carbohydrate Polymers (IF = 12.5). Ding Tingting, a Master's student, and Professor Fan Bei are co-first authors; Associate Professor Sun Jing and Professor Wang Fengzhong are co-corresponding authors. The research was supported by the Shandong Provincial Key R&D Program (2024SFGC0401) and the Major Science and Technology Project of Yunnan Province (202402AE090011), etc.

With the global aging population rapidly increasing, dysphagia has become a prominent issue threatening the health and quality of life of the elderly. However, most liquid foods currently available on the market suffer from limitations such as poor nutritional balance, uneven texture, and low palatability, failing to meet the dual demands of nutritional adequacy and sensory acceptability for special-needs populations. Therefore, the team innovatively integrated traditional medicinal and edible raw materials with modern colloidal food science to develop a novel functional food matrix that complies with the standardized International Dysphagia Diet Initiative (IDDSI) framework.

This study firstly constructed an alkaline-induced DOP-HSP hydrogel system. By precisely modulating the DOP concentration gradient (1.0%–3.0% w/v), the researchers systematically evaluated the physicochemical properties, functional performance, and biocompatibility of the composite hydrogels. The results showed that DOP, characterized by its unique branched structure and acetylation patterns, significantly improved the water-holding capacity, mechanical strength, and viscoelasticity of the gels. Meanwhile, HSP contributed a complete profile of essential amino acids, including approximately 12% arginine. The synergistic interaction between DOP and HSP enabled the resulting hydrogels to meet IDDSI level 5–6 standards, ensuring safety and suitability for dysphagic populations.

Further characterization using scanning electron microscopy, confocal laser scanning microscopy, and rheological analysis elucidated the gelation mechanism. Under alkaline conditions, DOP underwent deacetylation, exposing additional hydroxyl groups that facilitated hydrogen bonding with HSP. This interaction induced protein conformational transitions into β-sheet structures, ultimately forming a compact three-dimensional network. Disulfide bonds were identified as the dominant force stabilizing the hydrogel matrix.

This research not only provides a customizable food matrix solution for individuals with swallowing disorders but also opens new avenues for applying plant-derived polysaccharides and proteins in functional food development.

Article link: https://doi.org/10.1016/j.carbpol.2025.124153