Preparation Of Cyperus Esculentus L.cross-linked Esterified Starch And Its Application In Vegetarian Sausage

As a new type of starch resource,cyperus esculentus L.starch has both development and research value.However,compared with other raw starches,cyperus esculentus L.starch also has the defects of easy aging and high sensitivity to thermal decomposition.In order to broaden its application scope in food and other industrial fields,modification treatment is required,the cross-linking esterification modification is one of the most commonly used modification methods.In this study,the cyperus esculentus L.starch was used as the raw material,sodium trimetaphosphate(STMP)as the cross-linking agent and acetic anhydride as the esterification agent to prepare the cross-linked esterified starch,then its physicochemical properties and morphological structure were analyzed.Finally,it was applied to vegetarian sausages,the optimal preparation process was determined by response surface methodology,and the physicochemical properties and sensory properties of vegetarian sausages were analyzed.(1)0.5%,1.0% and 2.0%(m/m)of STMP were used as cross-linking agent to prepare the cross-linked starches which had different bound phosphorus content,and its properties were studied.The bound phosphorus content of the cross-linked starches of cyperus esculentus L.complies with the standard of edible starch.Compared with raw starch,the transparency,oil holding capacity,solubility and swelling power of cyperus esculentus L.starch were lower,but water holding capacity,aging resistance,gelatinization temperature,thermal stability of starch paste,freeze-thaw stability and digestion resistance were improved.When the addition amount of STMP was 0.5%,the peak viscosity,solubility,swelling power,transparency,oil holding capacity and water holding capacity of starch were higher than those of starches with other cross-linking agent additions.The occurrence of cross-linking reaction was confirmed by the Fourier transform infrared spectroscopy analysis.Fourier transform infrared deconvolution spectra showed that the short-range order of starch helical structure was improved compared with raw starches when the cross-linking agent was added at 2.0%.Scanning electron microscope observed that the edges of the cross-linked starch granules became blurred and the dents appeared on the surface.(2)The cross-linked starch of cyperus esculentus L.which had 0.5% STMP content was used as raw material,and 2%,4%,6%,and 8%(m/m)acetic anhydride were used as esterification agent to prepare the cross-linked esterified starches.Then the physicochemical properties and morphological structure of the obtained starches were detected and characterized.The acetyl group content of the cross-linked esterified starches of cyperus esculentus L.complied with the national standard of edible starch,and the reaction efficiency decreased with the increase of acetic anhydride.The solubility,swelling power,water holding capacity,oil holding capacity,peak viscosity,freeze-thaw stability and resistant starch content were higher than those of raw starch and cross-linked starches.The clarity was higher than that of cross-linked starches,but lower than that of raw starch,and the gelatinization temperature was reduced.The occurrence of the esterification reaction was confirmed by Fourier transform infrared spectroscopy.It was observed by scanning electron microscope that the surface of starch became rough,and when the addition of acetic anhydride reached at 8%,some pores appeared on the surface of starch granules.(3)Through single factor and response surface optimization experiments,the optimal process for the preparation of vegetarian sausages was obtained as follows: the addition of complex gum was 2.6%,the addition of starch was 10.2%,and the addition of soybean oil was 9.9%.Based on this condition,cyperus esculentus L.starch,cross-linked starch and cross-linked esterified starch were added respectively for the comparison.Through the detection of vegetarian sausage moisture,protein and fat,it is concluded that the prepared vegetarian sausage protein content conforms to the group standard Plant-based meat products.Starch had little effect on intestinal color and would not affect consumers’ choice.The addition of modified starch could improve the water holding capacity,oil holding capacity and gel strength of vegetarian sausage,and reduced the cooking-loss rate.According to the low field NMR water relaxation characteristics and imaging analysis,modified starches could improve the water retention of vegetarian sausage,and the cross-linked esterified starch was more obvious.The texture analysis and sensory evaluation showed that the addition of cross-linked and cross-linked esterified starches had an effect on the hardness of vegetarian sausage.Compared with raw starch and cross-linked starch,the vegetarian sausage which added cross-linked esterified starch had better elasticity and cohesion,and the sensory score also showed great advantages,which was more easily accepted by consumers.High water retention,oil retention and freeze-thaw stability made cross-linked esterified starch more suitable as a thickener,water-retaining agent,and emulsifier,which could be applied to the food processing for salad,pie,meat products and so on.