Preparation And Application Of Lotus Root Starch-whey Protein Isolate Composite Gel

Lotus root is an important economic plant and widely distributed in China,India,Japan and Australia.It has been reported that lotus root contains much starch,dietary fibres,proteins,amino acids,and vitamins.Among all nutritional components,starch has been proved to be the largest component in lotus root.Whey protein isolate?WPI?,a by-product of cheese production,has been widely used as edible protein due to its great nutritional benefits.Additionally,the gelation is another important property of the WPI.Thus,WPI is often considered as a food additive to improve the texture and taste characteristics of the food.Previous study revealed that the formation of WPI gels were influenced by polysaccharides,pH and salt ions.In this study,the effects of LRA,pH and salt ions on the formation of LRA-WPI composite gel were investigated.In addition,we discussed the effects of LRA-WPI composite gel on the encapsulation and bioavailability of VD3.The main results obtained in this study are shown as the follows:?1?The effects of LRA on the formation of WPI gel were investigated.Results exhibited the gel properties of LRA-WPI composite gel were gradually enhanced with the addition of LRA from 0 to 1%?w/v?.Compared the gel with free of LRA,the gel strength and water holding capacity?WHC?of WPI gel containing 1%?w/v?LRA were enhanced by 12.7-fold and 24.9%,respectively.In addition,the storage modulus?G'?,loss modulus?G''?and thermal stablity were also increased.According to the analysis of scanning electron microscopy?SEM?,colorimetric reaction and Fourier transform infrared spectroscopy?FT-IR?measurements,it was concluded that the LRA-induced enhancement of LRA-WPI composite gel properties were possibly attributed to the formation of stable three-dimensional gel network,increased contents of reactive sulfhydryl group,C-N bond and N-H bond.?2?The effects of pH on the formation of LRA-WPI composite gel were investigated.Results exhibited the gel properties of LRA-WPI composite gel were increased at the pH range from 5 to 7,whereas decreased between 7 and 9.When the pH at 7,the LRA-WPI composite gel showed the highest gel strength,WHC,thermal stablity,G' and G''.The results of SEM,colorimetric reaction and FT-IR measurements showed that the suitable pH?pH=7?induced enhancement of LRA-WPI composite gel properties were possibly attributed to the formation of homogeneous and compact gel network,increased contents of disulfide bond,C-N bond and N-H bond.Therefore,pH=7 is the best condition for the formation of LRA-WPI composite gels?3?The effects of salt ions on the formation of LRA-WPI composite gel were investigated.Results exhibited that the gel properties of LRA-WPI composite gel showed an increased,followed by decreased at the concentration range from 0 to 0.2 M.Compared the gel with free of salt ions,when adding 0.1 M CaCl₂ or 0.05 M NaCl,the gel strength was increased by 2.2-fold,3.1-fold,the WHC was increased by 3.4%,2.2%,respectively.Moverover,the G' and thermal stablity were also improved.According to the results of SEM,colorimetric reaction and FT-IR,it was concluded that suitable salt ions concentration induced increasement of LRA-WPI composite gel properties were possibly attributed to the formation of stable gel network,increased contents of disulfide bond,C-N bond and N-H bond.?4?The effects of LRA-WPI composite gel on the stability and bioavailability of VD3 were investigated.It was found that the stability of VD3 could be increased by the encapsulation of in 4 ?storage,in room temperature storage or upon exposure to intensive UV-light.Moreover,the stability of VD3 in the presence of simulated intestinal fluid was increased by 60%.According to the resultsin vivo,it was showed that the bioavailability of VD3 could be improved by the encapsulation of WPI-LRA composite gel.