Research On The Preparation And Properties Of Vegetarian Casing Based On Sodium Alginate

The continuous development of the sausage industry,the shortage of natural casings,the increase in consumer safety awareness,and the increase in demand for halal food have driven researchers to find the best alternative to collagen casings,vegetarian casings have become a current research hotspot.At present,overseas studies have begun to involve the development of sodium alginate(SA)casings,but the pure SA film is brittle and poor in toughness,and although the reported casings have good macro properties,they have not been put into commercial use.In view of this,this article selected guar gum(GG)from 8 plant-derived polysaccharides as the film-forming substrate,optimized the best preparation process of SA-GG casing and characterized its structure.On this basis,the impact of commercial cooking conditions on the performance of casings was explored and SA-GG casings were finally applied to sausage packaging,providing theoretical and application guidance for the industrial production of vegetarian casings.The specific contents are as follows:1.According to the film's mechanical properties,barrier properties,transparency and other indicators,select the film-forming matrix from 8 kinds of plant-derived polysaccharides.The results show that the film added with sodium carboxymethyl cellulose and high methoxy pectin has good mechanical properties,but the water resistance and transparency are poor;the film added with modified starch has the worst mechanical properties;the addition of guar gum significantly improves the wet fracture stretch rate of the casing,which is expected to improve the brittle and fragile defects of SA film.In addition,guar gum is less prone to bacteria growth and cheaper than konjac gum,so it is selected as a film-forming substrate.2.Formula and process optimization of casing.The optimal preparation process of SA-GG film was optimized through single factor experiment and orthogonal experiment:the compound ratio of SA and GG was 8:2,drying temperature was 50?,glycerol was added 20%,Ca Cl₂ concentration was 10%,and crosslinking was conducted for 5 minutes.The composite score of the film prepared under this condition was 0.66,and its properties were compared with those of commercially available collagen casings.The results show that SA-GG film has lower swelling property,better moisture barrier performance,and wet mechanical properties close to commercially available collagen casing,which has the possibility of enema application.3.Use XRD,FTIR,SEM to characterize the structure of the casing.The results show that there are interactions such as hydrogen bonds between SA and GG after blending.Ca Cl₂ is cross-linked with the carboxyl groups of sodium alginate to form an"egg box"structure and there is no phase separation between the two components,which has good compatibility.Thermogravimetric analysis shows that SA-GG vegetarian casing has better thermal stability than a single SA film,and is feasible in the subsequent processing of casings.4.Take commercial steamed sausages as an example to further explore the application possibilities of SA-GG casings.The tensile strength of SA-GG casing after cooking is 5.82MPa,the elongation at break is 45.4%,the water vapor transmission coefficient is 0.47gmm/hm²·k Pa,and the transmittance at 600 nm is 75.68%.Compared with collagen casings treated under the same conditions,SA-GG casings have better barrier properties and transparency,which may protect sausages from moisture and quality loss,and have the potential for good application performance.Next apply SA-GG casings and commercially available collagen casings to sausage packaging and store the sausages at 4°C.Periodically measure the texture,p H,TBARS,moisture content and other indicators of the sausages to explore the application effects of the casings.The results show that the SA-GG casing prepared in this paper can reduce the water loss of sausages and slow down fat oxidation,thereby ensuring the quality of sausages.