Study Of Gel Properties And Application Of Chicken Bone Protein

There are lots of chicken bones in China,and the content of protein in chicken bone is as high as14.40%,of which the collagen protein accounts for 35%-40%.Therefore,carrying out research on gel properties of chicken bone collagen will enrich the gel sources and improve the added value of chicken bone.In this work,we studied the isolation and physicochemical properties of acid-soluble collagen?ASC?and pepsin-soluble collagen?PSC?from chicken bone.Then,we investigated the effect of heating temperatures and time on the structure and gel properties of chicken bone collagen.Besides,the relationship of hot-pressure extraction conditions and gel properties of chicken bone protein?CBP?was investigated,and the best extraction conditions was obtained.Finally,CBP prepared at best extraction temperature and time was used in chicken sausages to provid the reference for its industrial application.The results were as follows:ASC and PSC were isolated from the chicken bone and its structure was characterided.Results suggested that the yield,content of protein and hydroxyproline?Hyp?,and denaturation temperature of PSC were all higher than that of ASC.The amino acid profiles of ASC and PSC was similar to each other with high imino acid content,being 190 and 217 residues/1000 residues,respectively.Electrophoresis showed that ASC and PSC were type I collagen and consisted of two different?chains??₁ and?₂?,?chain and?chain.Fourier transform infrared spectroscopy confirmed their triple-helical structure,and indicated more intermolecular crosslinks in PSC.UV scanning showed that the maximum absorption peak of ASC and PSC occurred in 234 nm.Scanning electron microscopy?SEM?of ASC and PSC showed regular and fibrous network structure.These results indicated that enzymatic extraction is more suitable to extract collagen from chicken bone.The influence of heat treatment on the structure and gel properties of chicken bone collagen was investigated.The results showed that the protein solubility increased significantly and the degree of hydrolysis reduced significantly during heat treatment?P<0.05?.Heat treatment caused the degradation of collagen,meanwhile macromolecular proteins were formed by cross-linking of small molecular proteins.Secondray structure of collagen changed significantly upon heating,with relative content of?-sheet decreased and random coil increased significantly?P<0.05?.Gelatin gels prepared by collagen hydrolysates?gelatin?obtained at 90?for 30 min exhibited higher melting temperature,better gel structure and higher texture profile analysis?TPA?values when compared to 50 and 70??P<0.05?.Hot-pressure extraction was utilized to prepare chicken bone protein?CBP?to study the effect of extraction temperature and time on gel properties.The study was expected to provide a reference for the preparation technology of edible gel by using chicken bone by-products.The results showed that hot-pressure extraction temperatures and time had a significant effect on the yield of CBP?P<0.05?,leading to the variable structure of protein and consequently affected the properties of CBP gels.Results of colour suggested that gels prepared by CBP of 120 min at 120?,60 min at 130?and 20 min at 135?were better than others.CBP gels of 60,90 and 120 min at 120?has higher melting temperature?25.10,23.10and 22.10?,respectively?and better stability than others.CBP obtained at 120 min at 120?had the highest viscosity.Results of TPA suggested that CBP gels of 90 and 120 min at 120?was higher than others.Correlation analysis showed that the content of Hyp,degradation of protein were considerably related to gelatin properties?P<0.05?.Given yield of protein,colour of gelatin,TPA,melting temperature etc.,CBP extracted at 120 min?120??were more proper for preparation of gel.The effect of CBP addition at different levels on properties of chicken sausages was investigated to provide the reference for its industrial application.The results indicated that the proportion of CBP has a significant impact on the quality of the chicken sausages?P<0.05?.The cooking loss of CBP2?0.50g/100 g?was significantly lower than others,while excess addition of CBP?1.00 g/100 g,1.50 g/100 g and 2.00 g/100 g?caused the increase of cooking loss?P<0.05?.Sausages with 0.25 g/100 g CBP had the lowest total expressible fluid of 23.02%.Colour analysis showed that sausages of 0.50 g/100 g CBP had the best colour,with highest L*and whiteness and lowest a*.Results of TPA indicated that proper addition of CBP?0.25 g/100 g and 0.50 g/100 g?is helpful to the improvement of hardness and springness,while excessive addition of CBP?1.00 g/100 g,1.50 g/100 g and 2.00 g/100 g?will lead to the decreased of hardness,springiness and chewiness of chicken sausages.SEM of sausages suggested that C,CBP1and CBP2 had good microstructure of three dimensional network.And CBP1 and CBP2 got highest scores of sensory evaluation.These results indicated that chicken sausages of CBP1?0.25 g/100 g?and CBP2?0.50 g/100 g?were the best in quality.