This study aimed to design a Pickering emulsion (PE) stabilized by whey protein isolate nanofibers (WPINs) prepared with subcritical water (SW) to encapsulate and prevent curcumin (Cur) degradation. Cur-loaded WPINs–SW stabilized PE (WPINs–SW–PE) and hydrothermally prepared WPINs stabilized PE (WPINs–H–PE) were characterized using the particle size, zeta potential, Congo Red, CD, and TEM. The results indicated that WPINs–SW–PE and WPINs–H–PE showed regular spherical shapes with average lengths of 26.88 ± 1.11 μm and 175.99 ± 2.31 μm, and zeta potential values were −38.00 ± 1.00 mV and −34.60 ± 2.03 mV, respectively. The encapsulation efficiencies of WPINs–SW–PE and WPINs–H–PE for Cur were 96.72 ± 1.05% and 94.07 ± 2.35%. The bio-accessibility of Cur of WPINs–SW–PE and WPINs–H–PE were 57.52 ± 1.24% and 21.94 ± 2.09%. In addition, WPINs–SW–PE had a better loading effect and antioxidant activities compared with WPINs–H–PE. SW could be a potential processing method to prepare a PE, laying the foundation for the subsequent production of functional foods.

Deer tendon, a deer processing byproduct, is an excellent protein source for the preparation of peptides for improving osteoporosis by its high protein content and high nutritional value. The optimal process of collagen acid extraction was implemented and the results showed that the acid concentration was 7%, the material–liquid ratio was 1:25, and the soaking time was 48 h. DTCHs could promote MC3T3-E1 cell proliferation and increase alkaline phosphatase activities in vitro. In addition, compared with the model group, the DTCHs treatment groups with an oral dosage of 350, 750, and 1500 mg/kg rat/day could significantly improve the shape, weight, bone mechanics, and alkaline phosphatase activities of tail-suspended mice. Bone microstructure and mineralization also recovered significantly in vivo. This result is expected to provide the structural and biological information for DTCHs-based functional foods.