Spray Drying Of Lotus Protein And Its Effect On Functional Properties

Lotus seed get the favor of people all the time,because it has special rich nutritional value and medicinal value.Lotus seed protein is important for lotus seed,and it is also an important limiting factor in its processing technology.But the functional features of lotus seed protein did not get in-depth study,the health care function and the functional food development of it are hindered in some extent.This paper was designed on the basis of the previous research of our laboratory,lotus protein was dried by Spray Drying,then the spray drying conditions would be optimized.At the same time,a comparative analysis about spray-drying lotus protein(SDLP)and freeze-drying lotus protein(FDLP)on basic components,color difference,structures and functional properties were investigated,and the antioxidant properties of SDLP were analyzed,all of this was laid a foundation for the development and processing of lotus seed health food.The main results were as follows:1.Lotus protein was prepared by alkaline extraction followed by isoelectric precipitation,then dried by spray drying,the effects parameters were explored by single factor and L9(34)orthogonal experiment,the results indicated that the optimal spray drying conditions were the sample concentration of 10%(w/v),inlet air temperature of 170?,the sample pH of 10 and flux rate of 15%.The basic components and color difference of SDLP and FDLP were investigated,moisture content of FDLP was significantly higher than that of SDLP(p<0.05),the soluble protein content of SDLP(87.25%)was also higher than FDLP(80.94%),but the ash content of the two kinds of drying protein were both higher than that of lotus seed powder,this was likely to be affected by the adding ions in extraction processing.For the color,SDLP was lightness,but the FDLP was partial red and yellow.2.The influence on structure and function characteristics to lotus seed protein powder dried by spray drying and freeze drying was analyzed.Scanning electron microscopy(SEM)showed that SDLP had folded or wrinkled morphology but FDLP had plate-shaped morphology structure.Differential scanning heat meter(DSC)results showed that the peak temperature,terminate temperature and enthalpy of SDLP were lower than that of FDLP,but the initial temperature of SDLP were higher than that of FDLP.The results of SDS-PAGE and Fourier infrared spectrum(FTIR)showed that two kinds of drying methods did not destroy the molecular weight distribution of protein.X-ray diffraction determination showed that two methods of drying protein were non-crystalline.Circular dichroism spectrum showed that the secondary structure of the two kinds of drying protein had no obvious changes,but both changed from rule structures to no rule structures.SDLP had higher water-holding capacity and foaming properties than FDLP,but FDLP had higher solubility,oil-holding capacity and emulsifying activity than SDLP.3.The simulated gastrointestinal digestion were employed to hydrolysis SDLP,the oxidation resistance of digested peptide was measured by different ways,the results showed that the oxidation resistance of digested peptide was related with concentration of sample,and higher than the original lotus seed at the sample concentration.The Sephadex G-25 was used to purified the digested peptides,four kinds of peptides with different molecular weight were got,the main composition of antioxidant activity was proved to be focused in peak ? through the determination of its oxidation resistance,the molecular weight of peak ? was 1405-1405 Da.