Proteins and polysaccharides are two main groups of functional components in food formulation. They play different roles in food industry due to their physico-chemical properties, such as; thickening agent emulsifying agent and stabilising agent. By Complex formation between the protein and polysaccharide, functional properties of proteins are improved. Among the different types of interactions between the protein– polysaccharide, covalent bond is very strong, specific, non electrostatic and permanent linkage. So, the maillard reaction between proteins and polysaccharides can be used to form a covalent bond because of safety and without the use of extraneous chemicals. In this study, the functional properties of soy proteins by formation covalent bonds between starch by use of the maillrd reaction was improved. To achieve the above objectives, on the basis of the total biopolymer (4% (w/w)), a mixture of soy protein and native starch and hydrolyzed starch (i.e., hydrolyzed for 20, 40 and 60 minutes) by 1:1, 1: 2 and 1: 3 protein / polysaccharide ratio were prepared. The pH value of the mixtures was adjusted to pH 9 and heated for 6 hour. Disappearing some soy protein bands, and highlighted bands more at the beginning of conjugated samples at the SDS-PAGE gel, also peak shift of soy protein and starch, especially the peak of the amide bond of 1 and 2 in the FT-IR spectrum of the soy protein - starch conjugate showed the complex formed between them. Evaluation of physicochemical properties of soy protein – starch conjugate, indicated that surface hydrophobicity of protein decreased, and water absorption, solubility, especially at the isoelectric point, and the zeta potential increased. The emulsion activity and emulsion stability of conjugated samples were evaluated with use of turbidity measurement and comparison average droplet size in the beginning and after 28 days ( p 0.05). Soy protein was used as a control sample. The results showed that the samples with 1:3 protein / polysaccharide ratio by native starch and 20 minutes hydrolysied starch, and with 1:1 protein / polysaccharide ratio by 40 and 60 minutes hydrolysied starch had the highest stability compared with the control sample. Finally, the samples with 1: 3 protein / polysaccharide ratio by native starch and 1: 1 protein / polysaccharide ratio by 60 minutes hydrolysied starch indicated better function than the other samples because of lower primary average particle size. In order to evaluate the effects of conjugated samples on quality characteristics of whipping cream, conjugated samples with 1:1 and 1:3 protein / polysaccharide ratio by hydrolysied starch between 0-60 minutes at a concentration of 1-2% were added to whipping cream with 20-30% fat. The RSM methodology was use for evaluating the effects of these characteristics. With increasing in fat content, overrun, firmness and stability significantly increased and synersis decreased. With increasing in conjugated samples concentration, overrun significantly increased and, synersis and firmness decreased. Also, increasing stability was near significant value (. p =.0556). The only significant effect of starch hydrolysis was on the firmness, that by increasing time of hydrolysis, the firmness increased. Conjugated sample type had a significant effect on the characteristics of whipping cream. Conjugated samples with ratio of 1:1 had the greatest effect on stability and overrun. Conjugated samples with 1: 1 protein / polysaccharide ratio led to more stability, and better able to compensate for the effects of fat reduction. Also, its effect was lower on the firmness. Keyborad : Emulsion, Conjugate, Covalent bond, Maillard, Soy protein, Starch