Effect of proteins on thermal and functional properties of corn, potato, rice and wheat starches

OLIETE, B.; RIBOTTA, P. D.; GÓMEZ M.; LEÓN, A. E.; PÉREZ, G. T.

Madrid, Spain

Congreso; 13th ICC Cereal and Bread Congress. Cereals in the 21st century: present and future; 2008

ICC International

Interactions among protein and starch play an important role in the properties of food products. The study of food ingredient interactions can supply information for the food industry and enhances the understanding of ingredients functionalities in real food systems. The influence of different proteins: gluten (G), soybean protein isolated (S), pea protein isolated (Pi), ovoalbumin (O) and whey (Wy) on gelatinization, retrogradation and pasting characteristics of four food starches: rice (R), corn (C), wheat (W) and potato (P) were investigated. Thermal analyses of starches and starch-protein slurries (starch:protein 80:20; solid:water 1:3), were performed in a DSC823e calorimeter (Mettler Toledo, Switzerland). Pasting properties were determined using a Rapid Visco-Analyser (RVA Newport Scientific, Australia). Protein incorporation modified the thermal behavior of starches and the effect depended on protein and starch type, even though proteins did not show endothermic or exothermic transition in DSC thermogram. The onset and peak temperature of gelatinization values of starches were in general increased by protein addition. The gelatinization enthalpy (expressed in J/g starch weight) was changed by some proteins. The most important modifications in gelatinization transition were caused by soybean proteins. Corn gelatinization enthalpy increased (C: 8.68; CS: 9.13 J/g, p<0.05), while the opposite trend was observed when potato starch was used (P: 17.66; PS: 12.08 J/g, p<0.05). Protein incorporation strongly decreased viscosity parameters related to a dilution effect by starch. However starch:ovoalbumin slurries presented higher peak viscosity, final viscosity and setback than other starch:protein blends. On the other hand, the setback of potato starch was strongly decreased by ovoalbumin addition. Starch retrogradation behavior was more affected by protein addition than gelatinization. Ovoalbumin increased significantly (p<0.05) the retrogradation degree of corn, wheat and potato starches (C: 21.55%, CO: 38.19%, W: 17.9%, WO: 31.95%, P: 29.68%, PO: 37.63%). The completely different effect of some proteins on thermal and pasting behavior of different starches suggested that water competition is not the only factor that modified gelatinization and pasting parameters; specific starch-protein interactions greatly contribute to the starch behavior.