Physicochemical And Biochemical Characteristics Of Soymilk Cheese During Ripening

In this paper, cooked soymilk was coagulated with acid-coagulant, salt-coagulant andsoymilk clotting enzyme respectively, to get the technological routes and parameters ofmaking fresh soft soymilk cheeses; and then make them into semi-hard soymilk cheeses. Thevariety of physical and chemical indexs during the ripeing of semi-hard soymilk cheeses wasresearched, then we compared the physicochemical, sensory and biochemical properties ofthe three semi-hard soymilk cheeses. The main conclusions were obtained as follows:1. Acid, inorganic salt and soymilk clotting enzyme can be used to coagulate soymilk,these coaulants have their appropriate temperature and addition amount respectively.Different temperatures and addition amounts both have important effects on coagulating time,coagulating state, coagulum texture and whey OD value of soymilk.2. Compared with the coagulum from soymilk treated with GDL and MgCl₂, the textureof papain-induced coagulum was smooth, but it was of low hardness and high adhesiveness,the network structure was unsharp and gathered as clouds. The whey could not easily drainfrom the coagulum and it’s not good for cutting. Adding CaCl₂could shorten clotting time ofsoymilk induced by papain and improve the hardness and adhesiveness of the coagulum.3. The optimum technological parameters of GDL soymilk cheese were as follows: theaddition amount of culture0.020%, coagulant0.20%and salt1.0%; for MgCl₂soymilkcheese:0.020%,0.20%, and1.0%; and for papain, the amounts of lactic culture, CaCl₂,papain and salt were found to be0.010%,0.02%,0.05%, and1.0%respectively. We can gethigher yields and better qualities of soymilk cheeses.4. Among the three kinds of fresh soft soymilk cheeses, the sensory score of papainsoymilk cheese, the protein content of MgCl₂soymilk cheese and the yield of GDL soymilkcheese were the highest respectively. Comparing the physicochemical and sensory propertiesof fresh soft soymilk cheeses and fresh soft bovine milk cheese under the same technologicalconditions, the results showed that the protein contents of them were similar and the sensoryscores of soymilk cheeses were a little lower than that of the bovine one.5. The pH value of papain semi-hard soymilk cheese descended at the initial stages, andthen ascended during the later ripening stages, and the final pH value was reach to5.04. The content of pH4.6soluble nitrogen, amino nitrogen and free fatty acid increased graduallyduring ripening. The total free amino acid of riped papain semi-hard soymilk cheese wasincreased, and the nutritional value of cheese was improved. After ripening, its microstructurebecome loose, and the subunits of the electrophoretic band disappeared. These showed thatthe soymilk protein and fat hydrolyzed by the action of papain and culture. But thesemi-hard soymilk cheeses made by MgCl₂å’ŒGDL had no substantial changes duringripeing.6. The saltness of the three kinds of semi-hard soymilk cheeses were between2%and4%, the yields and moisture contents of the MgCl₂and GDL soymilk cheese were similar, andhigher than papain soymilk cheese significantly. The fat content of the papain soymilk cheeseand the protein content of the MgCl₂soymilk cheese were highest in these three. Papainsoymilk cheese smelled bean flavor, tasted freshness and with fine organization, but it wassoft and easy to be broken. The flavour of MgCl₂and GDL soymilk cheeses was similar withtofu, these two cheeses featured bright surface, homogeneous struture, and had good hardnessand flexibility. To taste, MgCl₂and GDL soymilk cheeses was similar to dried bean curd, thepapain soymilk cheese had a sticky mouthfeel and it’s better to eat with sliced bread. The TPAresults showed that the adhesiveness of the papain soymilk cheese was higher than that of theMgCl₂and GDL soymilk cheeses, but lower in the indexs of hardness, cohesiveness,springiness, gumminess and chewiness.