The Development Of Low GI Potato Steamed Bread And Its Effect On The In Vitro Digestion Release Of Procyanidins

The"potato staple food"policy can be realized by processing potatoes into traditional staple foods such as steamed breads.However,potato steamed breads usually have high glycemic index(GI),long-term intake will increase the risk of type?diabetes and limit the development of the relevant industry.Grape seed procyanidins(GSP)can inhibit the digestion of starch by inhibiting the activity of amylase,or by combining with starch through non-covalent bonds.However,research on the combination of GSP and potato starch and its anti-digestive effect is still lacking.In addition,adding GSP will also reduce the sensory quality of food and limit its application in food industry.Therefore,this article firstly complexed potato starch and GSP,analyzed its structure,physicochemical and digestive properties,and explored the mechanism of GSP inhibiting potato starch digestion.On this basis,the recipe of potato steamed breads was optimized from the perspective of sensory and GI.Finally,from the microstructure and the digestive properties points of view,the regulatory effects of different food matrices on GSP release were evaluated.Conclusions as below:(1)Potato starch had a high loading rate to GSP(68.49?73.41%).The complex had better thermal stability and shear resistance on the RVA spectra.With the increase of GSP addition,DSC showed that the gelatinization temperature and enthalpy of starch increased.XRD and FTIR spectra showed that GSP might combined with potato starch through hydrogen bonds,changing the crystal structure of starch.TPA indicated that the combination of GSP inhibited the aging of starch.Most of all,the content of RDS decreased by 28.77%,the content of SDS increased by 19.51%and RS increased by9.35%with the increase of GSP addition.(2)This part looked at the effects of potato flour,water,yeast,GSP and vital gluten on the sensory,physical properties and GI of steamed breads.The addition of potato flour and GSP could reduce the GI of steamed breads,but it would destroy the sensory of steamed breads.Water and yeast could optimize the sensory of steamed breads but would increase the GI of steamed breads.Vital gluten could not only optimize the sensory of steamed breads,but also reduce the GI of it.Through L₉(3⁴)orthogonal optimization,the optimal formula was determined to be:15%replacement of potato flour,75%of water addition,1.0%of yeast addition,1.5%of GSP addition and 6.0%of vital gluten addition.Under these conditions,the sensory score of steamed breads reached 86.4,and GI also reached a low level(54.21).(3)In order to explore the matrix effect on the stability of GSP in steamed bread during processing and digestion,two wheat products with different food matrices were prepared by using the optimized formula as comparison:bread and noodles.The results showed that the loss of GSP was 24.01%and 37.90%after baking and boiling,respectively,and the loss of GSP after steaming was even lower,which was 20.38%.After in vitro digestion,the release patterns of GSP in three food matrices were similar.The GSP content in digestive fluid was the highest in stomach,followed by oral,lower in intestine,and the lowest in intestinal dialysate.Observing the microstructure of different matrices by SEM and CLSM,it was found that a compact and complete matrix structure could better maintain the stability of GSP during the in vitro digestion process.