Constructing an edible extracellular matrix (ECM) scaffold with good thermal stability, self-assembly properties and biocompatibility is crucial for manufacturing structured cell cultured meat products. In this study, carboxymethyl chitosan (CMCS) was introduced into the bovine bone collagen (BBC) system. Using ultraviolet (UV) absorption, infrared(IR) and fluorescence spectroscopy, it was found that the interaction between BBC and CMCS was enhanced with the increase in CMCS concentration, without affecting the triple-helical structure. The results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the introduction of CMCS reinforced the thermal stability of BBC. Turbidity test, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed an increase in the degree of fibrillogenesis and aggregation behavior and changes in self-assembly rate; a looser and twisted three-dimensional structure with a larger fibril diameter and a wider diameter distribution was observed after the introduction of CMCS. However, the introduction of CMCS did not significantly affect the formation and length of D-periodicity (a characteristic alternating light/dark transverse stripe structure formed during the self-assembly process of collagen fibers) in BBC, and there was no significant difference in the cell compatibility of the system before and after the introduction of CMCS. The BBC-CMCS interaction might be dominated more by electrostatic forces than covalent interactions and hydrogen bonds with the increase in CMCS concentration. These results indicated that the introduction of CMCS improved the thermal stability and self-assembly properties of BBC without affecting its biocompatibility or triple-helical integrity. This study provides a reference for the development of excellent edible collagen-based ECM as a biomimetic scaffold for cultured meat and for the deep processing and high-value utilization of livestock and poultry bone by-products.


In order to investigate the application potential of prolyl endopeptidase (PEP) in the enzymatic preparation of bone collagen peptides, the amino acid sequence characteristics of bovine bone collagen (BBC), porcine bone collagen (PBC) and chicken bone collagen (CBC) were comparatively analyzed, and their potential enzymatic cleavage sites and theoretical hydrolysis degrees were predicted. Collagen hydrolyzed by PEP at 55 ℃ and pH 8.0 was characterized by hydrolysis degree, molecular mass distributionand scanning electron microscopy (SEM). Infrared spectroscopy, X-ray diffraction (XRD) and circular dichroism (CD) spectroscopy were used to explore the structural changes of collagen during enzymatic digestion. The results showed that PEP could hydrolyze the three collagens. The hydrolysis degree of PBC was the highest (51.35%), followed by those of BBC (22.81%) and CBC (29.81%). The molecular masses of the three collagen hydrolysates were mostly distributed below 500 Da. Spectroscopic analysis showed that PEP destroyed the triple helix structure of collagen, and then degraded it. Therefore, PEP can efficiently enzymatically hydrolyze collagen into small molecule peptides, which provides a basis for the enzymatic preparation of functional collagen-derived peptides.
The preparation of bone peptides (livestock and poultry bone peptides, LBPs) for the development of bone-derived functional foods is one of the important ways for the high-value utilization of livestock and poultry bone by-products. In this experiment, the leg bone from four main livestock and poultry species were used as raw materials to prepare LBPs based on the same process, and their physicochemical properties and bioactivities were compared and analyzed, so as to provide the reference for the high-value utilization of livestock and poultry bone resources and the development of bone-derived functional foods.
Yak bone peptides (YBPs), bovine bone peptides (BBPs), porcine bone peptides (PBPs) and chicken bone peptides (CBPs) were prepared from yak, bovine, porcine and chicken leg bones, respectively. Physicochemical properties were characterized, including basic nutritional components, amino acid compositions, molecular weight and particle size distribution. Moreover, the bioactivities of the four LBPs, including osteoblast promoting proliferation, immune regulation, angiotensin converting enzyme inhibitors (ACEI) and antioxidation, were compared and analyzed.
The relative contents of crude protein in YBPs, BBPs and PBPs were (89.70±0.77)%, (90.43±0.88)% and (89.36±1.32)%, respectively, which were significant higher than that of CBPs (79.18±1.49)%). The essential amino acids and sulfur-amino acids of CBPs were significant higher than those of YBPs, BBPs and PBPs. The four LBPs were mainly composed of small molecular peptides with MW<2 kD, accounting for about 90%. There was no significant difference in particle size distribution of LBPs powder, which was mainly concentrated in the range of 10-20 µm and 40-60 µm. The bioactivities of different LBPs were analyzed. It was found that YBPs had the most significant osteoblasts promoting proliferation effect, and the proliferation rate was 37.27% at 0.5 mg∙mL-1; BBPs had the strongest effect on macrophage proliferation, and the proliferation rate was 39.26% at 5 mg∙mL-1; PBPs had the strongest ACEI activity, and the inhibition rate of ACE activity was 82.37% at 15 mg∙mL-1; YBPs had the strongest comprehensive antioxidant capacity, compared with BBPs, PBPs and CBPs.
The physicochemical properties of LBPs from four distinct species were different, but they all met the demand of raw material for the development of bone-derived functional foods. The bioactivities of LBPs from different species were different, which were suitable for the development of different bone-derived functional foods: YBPs had the strongest osteoblasts promoting proliferation effect and comprehensive antioxidant capacity, which was more suitable for the development of bone health improving or antioxidant bone-derived functional foods; BBPs had the strongest effect on promoting macrophage proliferation, which was more suitable for the development of immunomodulatory bone-derived functional foods; PBPs had the strongest ACEI activity and was more suitable for the development of bone-derived functional foods with blood pressure control effect; CBPs had the better powder properties and higher mineral content, which could be used as dietary nutritional supplements.

Bone collagen hydrolysates (peptides) derived from byproduct of animal product processing have been used to produce commercially valuable products due to their potential antioxidant activity. Maillard glycosylated reaction is considered as a promising method to enhance the antioxidant activity of peptides. Hence, this research aims at investigating the Maillard glycosylation activity and antioxidant activity of bone collagen hydrolysates from different sources. In this study, 3 glycosylated bone collagen hydrolysates were prepared and characterized, and cytotoxicity and antioxidant activity were analyzed and evaluated. The free amino groups loss, browning intensity, and fluorescence intensity of G-Cbcp (glycosylated chicken bone collagen hydrolysates (peptides)) were the heaviest, followed by G-Pbcp (glycosylated porcine bone collagen hydrolysates (peptides)) and G-Bbcp (glycosylated bovine bone collagen hydrolysates (peptides)). The results of amino acid analysis showed that amino acid composition of different bone collagen hydrolysates was significantly different and the amino acid decreased to different degrees after Maillard glycosylated reaction, which may lead to differences in Maillard glycosylated reaction activity. Furthermore, the 3 glycosylated hydrolysates showed no significant cytotoxicity. The results showed that glycosylation process significantly increased the antioxidant activity of bone collagen hydrolysates, and G-Cbcp showed the strongest antioxidant activity, followed by G-Pbcp and G-Bbcp. Therefore, compared with the bone collagen hydrolysates, 3 glycosylated hydrolysates showed significant characteristic and structural changes, and higher antioxidant activity.