| With cassava starch as material, carboxymethyl starch and carboxymethyl maltodextrin were prepared. Then physical and chemical properties were studied. Furthermore the application of carboxymethyl starch and carboxymethyl maltodextrin to sausage was studied. The main results were as follows:1. At first, the factors which affect preparation of carboxymethyl starch were studied by single factor experiment, such as: starch concentration, ethanol concentration,the mole ratio of CH2ClCOOH/starch,the mole ratio of NaOH/ starch, reaction temperature and reaction time. Then by orthogonal test we got the optimum technique parameters: starch/NaOH/CH2ClCOOH mole ratio is1?1.6?0.7,25% starch concentration, 75% ethanol concentration , reaction temperature is 50℃,reaction time is 3h.2. Properties of carboxymethyl starch. Properties of native starch and carboxymethyl starch were compared, the conclusions were as follows:Starch molecular and granular structure changed, caves and cracks appeared on the surface of granules. With DS increased, granules were further destroyed. This indicate that carboxymethylation occurres not only in the amorphous regions but also in the crystalline regions.IR spectrum of carboxymethyl starch changed significant compared with native starch. Strong anti-symmetric and symmetric stretching vibration absorption peak of COO-objection appears in the 1635cm-1 and 1426cm-1, indicating the occurrence of carboxymethylation. Also the hydroxyl absorption peak in the 3700 cm-1 ~ 3000cm-1 and in the 2929 cm-1 C-H stretching vibration absorption peak were decreased, indicating the replace of hydroxyl。Compared with native starch, transparency, freeze-thaw stability, retrogradation, emulsion and emulsion stability of carboxymethyl starch are improved , with increasing degree of substitution, transparency, retrogradation and freeze-thaw stability enhanced while the emulsification reduced.The double helix structure and crystalline structure of the crystalline region and amorphous area within starch granules was destroyed by strong alkali in the carboxymethyl process,finally DSC curve of carboxymethyl starch changed into a straight line.3.With different degree of substitution carboxymethyl starch hydrolysis in high-temperature, carboxymethyl maltodextrin was prepared. Then physical and chemical properties were studied. The main results were as follows:SEM images showed that the shape of particles cassava starch matrix fat mimics significant changed compared with native starch. The particle surface erode, the surface became rough and particle size was significantly smaller. Aggregation of starch granules occurred.The particle size of carboxymethyl maltodextrin is smaller than carboxymethyl starch and maltodextrin after Carboxymethyl and enzyme modification, average size reduced to 5μm. It is suitable as fat substitute.Fat mimics had good transparence and freeze-thaw stability, with increasing DE value, transparence increased while freeze-thaw stability reduced.As the temperature increasing, the solubility and swelling of fat mimics were increased. Water holding capacity of carboxymethyl maltodextrin was bigger compared with native starch while water holding capacity of maltodextrin lower and with the DE value increased, water holding capacity decreased.Compared with maltodextrin paste viscosity lower than native starch, with DE value increasing the paste viscosity decreased, while the paste viscosity of carboxymethyl maltodextrin larger than maltodextrin.Molecular weight and degree of dispersion of carboxymehtyl maltodextrin were smaller than carboxymehtyl starch.4. Fat mimics were used to replace part fat in the sausage. Hardness, adhesion, flexibility, cohesiveness, gumminess and chewiness of samples were overall evaluated by Texture Analyzer, found that DE 2.40 and DS 0.331 carboxymethyl maltodextrin can replace about 25% fat.
|
PDF Full Text Request