Study On The Wheat-Potato Yogurt Pie Bread Processing Optimization And Quality Characteristics Evaluation

Potato is the major staple food crop of China,many potato products have been made from potato that include potato steamed bread,potato bread,potato noodles,potato chips,potato cakes,and so on.Potato flour used as a potential food by replacing gluten containing wheat flour can enrich the nutritional value and profound functional properties of bread.The study has shown the viable use of potato flour with yogurt for pie bread making.In this study,effect of different proportions of potato flour and different kinds of yogurt on fermentation properties of dough and nutritional and functional properties of potato yogurt pie bread were investigated.On this basis,the formula of potato yogurt pie bread was optimized by investigating the influence of different kinds of ingredients on dough properties and quality characteristics of pie bread,thus providing a new kind of potato staple food for consumers.0%-60%of potato flour was used to study the effects of different proportions of potato flour on dough properties and quality of potato-wheat-yogurt pie bread.Fermentation rheological properties showed that the dough height?H_m?was decreased significantly but total gas volume?V_t?showed no significant difference with the addition of 10%-60%potato flour compared to dough with 0%potato flour?wheat flour?.SEM showed that dough with 10%-40%potato flour revealed smooth surface and continuous network structure of gluten,and NMR results revealed that the dough with 10%-60%potato flour presented larger water mobility than that of control.Proximate composition results depicted that addition of 0%to 60%potato flour in pie bread were increased the ash,dietary fibre,Ca,K,P,Mg,B₁,B₃ and resistant starch content,while exhibited lower fat,carbohydrate,Fe,Mn and Cu content and energy value.In addition,pie bread with 10%-40%potato flour presented similar specific volume,height/diameter ratio,and light color and texture properties compared to that of wheat pie bread.The overall results indicated that lower addition of potato flour?less than 40%?was suitable for potato yogurt pie bread processing from a sensory and nutrition perspective,thus,30%potato flour addition was used for the following studies.Effects of yogurt-1 Lactobacillus bacteria i.e.?Lactobacillus?yogurt-2?Bifidobacteria?and yogurt-3?Streptococcus thermophilus/Lactobacillus sspbulgaricus/Lactobacillus acidophilus?on dough properties and quality of potato yogurt pie bread were investigated.Dough height?H_m?significant decreased in yogurt pie dough1-3?YPD1-3?,but total gas volume?V_t?showed no significant difference.SEM images showed soft and smooth surface in yogurt pie dough when the three kinds of yogurt was added,and CLSM showed that there were some connections between protein and starch,which was similar to gluten network.With the addition of three kinds of yogurt highest bound water content were obtained in yogurt pie bread dough-1 compared to YPD2-3.The content of moisture,carbohydrate,protein,fat,dietary fibre and energy value showed no significant difference among the three kinds of yogurt pie bread except for ash content.YPB-2 obtained higher specific volume and height/diameter ratio than YPB-1and 3.YPB-1 bread showed the lowest hardness,springiness value compared to YPB-2 and YPB-3.Proline and glutamic acid were the major FAAs,which were 33.10 to 39.44,22.70 to 26.61 mg/100g DW in YPB-1,2 and 3.Overall total 51 kinds of volatile compounds were detected in three yogurt pie bread samples among them,YPB-1 bread showed highest 39 compounds volatile compounds,followed by YPB-3 and 2,alcohols category were dominant with others groups,while ethanol content were significant increase from 43.18%to 46.27%in YPB-1,2 and 3.On the basis of above investigations,it can be concluded that yogurt-1 proved to better potential dairy ingredient for yogurt pie bread formulation with rich flavor substances and it will be beneficial addition in consumer grocery markets.Four kinds of protein and hydrocolloids were used to investigate the different ingredients on the properties of dough and quality characteristics of pie bread.Compared to wheat flour dough H_m significantly decreased?P?0.05?.Dense gluten network,stiff and smooth surface dough observed with wheat and potato-wheat flour dough compared to thick gluten strands,scattered starch granules,and less cracks surface dough was observed in egg white protein?EWP?and total egg protein?TEP?protein added dough.The unbound water content T₂₂ significantly increased in EWP,TEP and carboxymethyl cellulose CMC added dough compared to wheat and potato-wheat dough.Moreover,specific volume and height diameter were significantly increased from 3.99 to 5.70 cm³/g,and 0.33 to 0.51 with addition of EWP,TEP and CMC in pie bread?P?0.05?,all pie bread added with EWP,TEP and CMC showed similar crumb color to wheat flour pie bread.Hardness and chewiness increased after addition of EWP,TEP and CMC compared to wheat flour pie bread and CMC+TEP pie bread showed lowest hardness and chewiness value that was 3717.66 N,2649.79 N,respectively.The sensory quality of pie bread were improved with addition of protein and hydrocolloid.The lowest count of yeast,mould and coli form bacteria were observed at 0.15mg/kg concentration of?-polylysine contain pie bread and extend 30 days of storage life.Therefore both kinds of protein showed that improved textural and other technological properties of pie bread.