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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Bioproducts Research » Research » Publications at this Location » Publication #403311

Research Project: Zero Waste Agricultural Processing

Location: Bioproducts Research

Title: Changes in structures and properties of collagen fibers during collagen casing film manufacturing

item LIU, FEI - Jiangnan University
item YU, ZHE - Jiangnan University
item WANG, BEIBEI - Jiangnan University
item Chiou, Bor-Sen

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/26/2023
Publication Date: 4/29/2023
Citation: Liu, F., Yu, Z., Wang, B., Chiou, B. 2023. Changes in structures and properties of collagen fibers during collagen casing film manufacturing. Foods. 12(9),1847.

Interpretive Summary: Collagen films produced from animal hides have been widely used as casings in the production of sausages. Collagen undergoes multiple treatments, including pulverization, acid swelling, neutralization, washing, and drying, during the entire production process. However, few studies have examined the effects of these treatments on the triple-helix structure and material properties of the collagen films. In this study, we examined the changes in the material properties of colllagen during each stage of production. We found that acid swelling destroyed some triple-helix structure of collagen and increased the size of the helix structure. Also, neutralization destroyed most of the collagen structure. However, the helix structures reformed during drying of the films, although these structures were less thermally stable than the original ones. These results can be used to optimize production of casings to improve their material properties.

Technical Abstract: Collagen casing is an edible film, which is widely used in the industrial production of sausages. However, the detailed changes of collagen fibers from raw material to final collagen film have been rarely reported. In this research, changes of collagen fibers during the manufacturing process, including fiber arrangement, triple-helix structure and thermal stability, was investigated using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The relationship between structure stability and the arrangement of collagen fibers was also discussed. According to the SEM, XRD, TGA, DSC and FTIR results, collagen fibers were depolymerized during acid swelling and became uniformly aligned after the homogenization process. Degassing had no obvious effect on the triple-helix structure. Alkaline neutralization with ammonia destroyed the triple-helix structure, which could be partly reversed by the washing and soaking processes. During the final drying step, the depolymerized triple-helix of collagen fibers recombined to form new structures that showed decreased thermal stability. This study expanded the knowledge about the behavior of collagen fibers during the industrial process of producing collagen biobased casings.