In the present paper, the role of amino acids of Penaeus vannamei was investigated in the formation of volatile substances during drying. The variations in volatile substances among samples with different moisture contents (raw, 45%, 30%, 15%, and 5%) were obtained by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS). The amino acid contents of the above samples were measured by the amino acid automatic analyzer. Correlation between pyrazines and the various amino acid contents was analyzed by the Pearson correlation coefficient. Their correlation was verified by conducting addition assays. The types and contents of volatile components increased significantly in samples with moisture contents between 30% and 5%. The most obvious increases in the type, content and odor activity value of pyrazines were observed in this range. Basic amino acids (Arg, Lys, and His) had a strong correlation with the formation of pyrazines. Addition assays verified that the addition of Arg and Lys increased the content of pyrazines in shrimp after drying.

Coconut kernel fiber (CKF) is a by-product of coconut oil processing; it is rich in protein and serves as a potential source of bioactive peptides. In this study, from the enzymatic hydrolysis products of CKF (CKFH), a low-molecular-weight CKFH component (LW-CKFH, 1–3 kDa), exhibiting 74.49% α-glucosidase inhibition and restoring glucose metabolism in IR-HepG2 cells to 71.37% of normal levels. In a type 2 diabetes (T2DM) mouse model, LW-CKFH alleviated insulin resistance and enhanced insulin sensitivity by repairing liver damage, thereby improving glucose and lipid metabolism and reducing inflammation; its effects on improving insulin resistance and sensitivity reached 75.43% and 75.47% of the efficacy of metformin, respectively. Molecular docking analysis identified FDLPAR, LPFPRPAGPR, and ANVFNPR as key active peptides responsible for inhibiting α-glucosidase activity. Furthermore, LW-CKFH exhibited good gastrointestinal digestibility and processing stability, while significantly reducing the glucose release rate from bread (>50%), indicating its suitability for the development of hypoglycemic or low-GI functional foods. LW-CKFH was particularly suitable as a functional ingredient for fruits, vegetables, grains, and dairy products to develop low-GI or hypoglycemic foods. This study provides new insights into the high-value utilization of the coconut processing by-product CKF.

Bullfrog skin, as a by-product of bullfrog processing, is an ideal source of high-quality collagen due to its high protein content and low-fat characteristics. However, its comprehensive utilization is relatively low, and the discarded skins cause resource waste and environmental pollution. In this study, a citric acid extraction process for frog skin collagen was established through single-factor optimization. A multifunctional double-network hydrogel was developed by combining the prepared high-purity type I collagen with oxidized hyaluronic acid (OHA). Due to the network structure design of Schiff base bonds and Zn²⁺ coordination bonds, the mechanical strength of the hydrogel based on collagen and OHA compositing Zn²⁺ (Gel–CO@Zn) enhanced significantly. It was found that the Gel–CO@Zn hydrogel had strong tissue adhesion (16.58 kPa shear strength), rapid self-healing (<6 h), and low hemolysis (60%) in the liver injury model of male Kunming mice. This research not only presents a novel approach for the high-value utilization of aquaculture by-products but also establishes a new paradigm for developing cost-effective, multifunctional biomedical materials, demonstrating the transformation of waste into high-value resources.