Preparation And Performance Evaluation Of A New Coating Material For Enhancing Collagen Sausage’s Meat Adhesion

Collagen casings have been widely being employed in sausage production due to their edibility and similarity in chemical structure to natural casings.Despite,since overseas enterprises have been blocking and shielding the production technologies,the domestic collagen casings are being suffered from poor meat adhesion.This study intends to use ε-polylysine(ε-PL)and epichlorohydrin(ECH)as raw materials to prepare a meat adhesion-enhancing coating material so as to provide guidance for solving the problem of poor meat adhesion of domestic collagen casings.ECH is a highly reactive chemical intermediate,whose epoxy group can react with the primary amine groups in ε-PL,forming ECH-modified ε-PL containing pendant hydroxyl azetidinium(ECH-ε-PL).The hydroxyl azetidinium is supposed to react with the-COOH groups from both collagen casings and meat stuffs,leading to enhanced casing-meat adhesion.ε-PL is a food additive approved by the Ministry of Health of the People’s Republic of China and ECH may hydrolyze into glycerol.Therefore,the proposed ECH-ε-PL is expected to be safe as a meat adhesion-enhancing coating material.First,we have synthesized ECH-ε-PL by using 30 wt% ε-PL aqueous solution,with the molar ratio of NH2 in ε-PL to ECH as 1 : 1.Results from GC-MS,element analysis,TGA,FTIR and 1H NMR demonstrated that ECH can be successfully grafted onto the side chains of ε-PL with the conversion ratio of ECH as 99.49%;Dialysis can remove about 98.6% of the byproduct,1,3-dichloro-2-propanol,and its final content is as low as 0.021 mg/m L.Second,dipping method was employed to coat ECH-ε-PL.The concentration of ECH-ε-PL was found to regulate the uptake of ECH-ε-PL by collagen casings,higher concentration leading to higher uptakes.Compared with the casings coated with 30 wt% ε-PL(MCC-P30)and the virgin casings(MCC-00),the casings coated with 10 wt%(MCC-EP10),20 wt%(MCC-EP20)and 30 wt% ECH-ε-PL(MCC-EP30)demonstrated stronger meat adhesion,presenting an order of MCC-EP30 > MCC-EP20 > MCC-EP10 > MCC-P30 ≈ MCC-00.This verifies that ECH-ε-PL as a coating material can enhance the meat adhesion of collagen casings yet the degree of enhancement is dependent on the uptake of ECH-ε-PL.Further detection of the peeling forces of casings from meat stuff and observations of meat-casing interfaces by HE staining indicated that the ECH-ε-PL coating promotes the interfacial fusion between the collagen casing and the meat by increasing the interaction sites of casing-meat interface,thereby enhancing the meat adhesion of collagen casings.Finally,the cytotoxicity of ECH-ε-PL was preliminarily evaluated by using rat mesenchymal stem cells as model cells.It was found that both the ECH-ε-PL solution(0.1 mg/m L,0.25 mg/m L,and 0.4 mg/m L)and the coated collagen casings(MCC-EP30,MCC-EP20,MCC-EP10)after stuffed with meat and then suffered from cooking have no significant cytotoxicity yet ε-PL solution and MCC-P30 have obviously stronger cytotoxicity.These results suggested that ECH-ε-PL hopefully had good safety.In conclusion,this study successfully established the preparation method of ECH-ε-PL.ECH-ε-PL as a coating material can significantly enhance the meat adhesion of collagen casings,and it is hopeful to become a new type of food additive to enhance the meat adhesion of collagen casings.