Effects Of Soluble Soybean Polysaccharide On The Batter And The Quality Of Spring Roll Wrappers In Frozen Storage

As a Chinese traditional snack,spring rolls are favored by consumers due to their golden appearance and crispy taste.Spring rolls are prepared with spring roll wrappers(SRW),an important raw material that plays a key impact on the quality of spring rolls.In recent years,with the industrialization of traditional Chinese foods,SRW has been industrially produced on a large scale and sold through cold chains in order to meet the demand of spring roll processing industry and self-help personalized consumption of families.However,the quality of SRW is deteriorated,including the water loss and crack of the surface due to temperature fluctuations during frozen storage and transportation or sales.The deterioration of SRW even affects the processing of spring rolls and leads to a decrease in crispiness and eating qualities of spring rolls.In order to solve the challenges in the SRW industry to explore a useful way for improving the quality of SRW,soluble soybean polysaccharide(SSPS)was added to wheat flour and its influence on the properties of the batter and frozen SRW as well as corresponding mechanism were investigated.The results obtained were as follows:(1)The influence of SSPS on the properties of flour-SSPS mixture and the batter The influence of SSPS supplement on the gelatinization properties of flour and the rheological behavior of the batter was studied using a rheometer.The results indicated that the addition of SSPS decreased the peak viscosity,trough viscosity,complete viscosity,breakdown value and setback value.Meanwhile,as the content of SSPS increased,the water separation rate of the batter decreased while the relative content of the?-type structure of the gluten protein increased,with increasing addition amount of SSPS.Besides,the rheological experiments showed that the batter was a pseudoplastic fluid,and the addition of SSPS reduced the fluidity of the batter and enhanced the consistency coefficient and yield stress,which was beneficial to the extension of the batter.In addition,the scanning electron microscopy(SEM)displayed that the swollen starch granules were buried deeply in the gluten in the batter with appropriate addition of SSPS,which promoted the formation of the gluten-starch network.When the addition amount of SSPS was 0.9%,the formation of gluten network structure and the swelling of starch were inhibited,and the quality of batter was reduced.Furthermore,the thermogravimetric tests and thermodynamic analysis revealed that water loss decreased,the temperature(T_o,T_pand T_c)and the gelatinization enthalpy value increased during the heating process of the batter.(2)The changes of processing properties and eating quality of SRW during freeze-thaw cyclesThe changes of processing properties and eating quality of SRW during freeze-thaw cycles were discussed using the physical and chemical analysis and the textural evaluation.It found that the addition of SSPS increased the moisture content and cohesion of SRW,reduced its hardness and adhesiveness,which helped to enhance the operability of the subsequent processing of SRW.In addition,SSPS inhibited the deterioration of the processing property of SRW in the freeze-thaw process.Otherwise,the addition of SSPS reduced the oil content of fried SRW,improved their brittleness and color as well as eating quality,especially with the highest sensory score at the addition of 0.6%SSPS.Besides,correlation analysis between the batter system and the quality of SRW indicated that the gelatinization properties of flour,the water separation rate of the batter,the?-helix,the fluid characteristic index and the mass loss during heating were mainly negatively related to the processing properties of the SRW and the sensory quality of the spring rolls,but positively related to the edible quality of SRW.However,the correlation of the intermolecular?-sheet,yield stress,consistency index and the thermodynamic properties of heating process on the processing properties,sensory quality and edible quality of spring roll skin is opposite to the former.(3)Effects of SSPS on water,starch,protein and the microstructure of SRW under freezing and thawing conditionsDifferential scanning calorimeter(DSC)and low-field nuclear magnetic resonance(LF-NMR)tests showed that during the freezing and thawing process,SRW with SSPS had a lower freezing water content and the water mobility than the control,indicating that SSPS inhibited the influence of ice crystal growth on the internal structure of SRW,reduced the extent of changes in the protein secondary structure,glutenin macromer(GMP)and free sulfhydryl content,and maintained the spatial conformation and network structure of gluten protein.SEM displayed that the addition of SSPS helped to preserve the tightness and continuity of the SRW structure,especially the SRW with0.6%SSPS having a large complete internal structure area after 12 freeze-thaw cycles.In addition,X-ray diffraction(XRD)and DSC tests reflected that the addition of SSPS inhibited the increase in starch crystallinity and aging enthalpy during the freezing and thawing process of SRW,and delayed the aging of SRW.Therefore,the results show that SSPS can be used as an effective food improver in the production and processing of quick-frozen SRW,and effectively promote the related quality of SRW.