The pH at which the protein as a whole has no net charge. Proteins contain many different protonatable groups. The pH at which half are positively charged and half are negatively charged is the isoelectric point. Based on the experiment when protein is in its isoelectric point it has the least solubility.
Tofu is a vegetable curd which is made from the fermentation of soybean, it is high in protein and is said to have lots of benefits to health. The factors affecting tofu production are coagulants and temperature and gel forming capacity of protein. Several factors affect gel formation, such as protein type, protein concentration, temperature, ionic strength, type of ion and pH. Based on the results of the experiment probably the two most important factors in gel formation are the protein concentration and heating temperature. If either, or both the temperature and protein concentration are too low, gel formation will not occur. Once these factors are above their critical values, gel strength increases and gel formation time decreases with increasing temperature and concentration.
Foams are dispersions of gases in liquids. Proteins stabilize by forming flexible, cohesive films around the gas bubbles. The more quickly a protein molecule diffuses into interfaces and the more easily it is denatured, the more it is able to foam. Based on the results of the experiment foams collapse because large gas bubbles grow at the expense of small bubbles.
Maillard reaction is of great importance in food manufacturing and its results can either desirable or undesirable. An example of the first kind is the brown crust formation on bread and one of the second kind is the brown discoloration of evaporated and sterilized milk. Maillard reaction was clearly shown in the experiment where in carbohydrate is reacted with different kinds of proteins.
Denaturation is a process of change in structure without breaking of covalent bonds. The process is peculiar to proteins and affects different proteins to different degrees. Denaturation is basically when a protein falls apart or unfolds due to heat, organic solvents, detergents, acids, base, etc. Coagulation is the precipitation of protein as molecules aggregate. In the process of coagulation, coagulate forms a clot, a semisolid mass, or a gel, after initial denaturation of a protein; to produce a firm mass or gel by denaturation of protein molecules followed by formation of new crosslinks. Coagulation and denaturation differences are shown in the experiment.
Opalescence is a type of dichroism seen in highly dispersed systems with little opacity. The solution appears yellowish-red in transmitted light and blue in scattered light perpendicular to the transmitted light. Appearance of the blue color at the surface of the egg white solution and the red color at the bottom was seen in the experiment.
Hydration of protein occurs when the water molecules coils with the protein molecules. The pH of meat in its isoelectric point has the least hydration and the above and below its isoelctric point hydration increases.
It is recommended that different protein sources must be used to check their physical and chemical properties. In the experiment conducted, following proper procedures must be implemented. All data were placed on a data book not on pieces of paper that might be misplaced. Keeping a data book will also avoid confusions and allows data exchange easily.