Study On Physicochemical Properties And Processing Properties Of Different Aquatic Vegetable Starches

Starch is one of the most abundant natural polysaccharides in plants.It is nontoxic,renewable and degradable.Aquatic vegetables are edible and medicinal vascular plants growing in fresh water,which are rich in nutrients.However,there are few researches on aquatic vegetable starches at domestic and abroad.Comparisons among starches obtained from these aquatic vegetables have not been reported.In this study,four kinds of aquatic vegetables:Nelumbo nucifera Gaertn.,Eleocharis dulcis,Sagittaria sagittifolia L.,and Trapa bispinosa Roxb.were used as research materials to explore the differences in the physicochemical properties and processing characteristics,as well as the effects of ultrahigh pressure and ultrasonic treatment on the physicochemical properties of S.sagittifolia starch and film properties,and through the study of the film forming process of S.sagittifolia starch-based film,to provide theoretical guidance for the further development and utilization of aquatic vegetables.The physicochemical properties and film properties of four aquatic vegetable starches were studied.The results showed that there were significant differences in transparency,freeze–thaw stability,water solubility index,swelling power,water and oil absorption capacities,starch particle morphology,and rheology were observed among the starches from four aquatic vegetables.S.sagittifolia starch had higher gelatinization transparency,better freeze-thaw stability,higher solubility and swelling power,and higher viscosity.Based on the preliminary study of the starch-based film,it was found that S.sagittifolia starch film had the highest transparency(61.99%),lower water vapor permeability coefficient(3.65×10^-10g·s^-1·m^-1·pa^-1)and water solubility(46.20%).S.sagittifolia starch was selected as the research object and treated with different pressures(0.1,150,300,450,600 MPa)at ultrahigh pressure.The results showed that ultrahigh pressure treatment significantly improved the water and oil absorption capacity of starch,decreased the light transmittance of starch-based film,and increased the water solubility of starch-based film.Under the pressure of 300MPa,the starch of S.sagittifolia had better gelatinization transparency and freeze-thaw stability,and the base film of S.sagittifolia starch had higher transparency(50.66%),lower water vapor permeability coefficient(3.03×10^-10g·s^-1·m^-1·pa^-1)and water solubility(51.73%).Based on the study of the physicochemical properties and film properties of S.sagittifolia starch treated by ultrasonic at different time(0,10,20,30,40 min).The results showed that ultrasonic treatment improved the water absorption ability,gelatinization transparency and freeze-thaw stability of S.sagittifolia starch,and reduced the transmittance and water solubility of S.sagittifolia starch-based film.When the treatment time was 20 min,the transparency(55.68%)of the starch-based film was higher,and the water vapor permeability coefficient(2.82×10^-10g·s^-1·m^-1·pa^-1)and water solubility(38.85%)were the minimum,which improved the properties of the starch-based film.Through the study of film forming process of S.sagittifolia starch-based film,the optimum formulation of starch-based film was determined as glycerin content1%,twain 80 content 0.05%,starch content 1.5%and sodium alginate concentration 1.25%.Under these parameters,the transparency of the starch-based film is 55.29%,and the water vapor permeability coefficient is 3.12×10^-10g·s^-1·m^-1·pa^-1,and the film has the best comprehensive performance.