Investigation On Casein Phosphopeptides In Lactobacillus Helveticus Dairy Products

Lactobacillus helveticus shows high proteolysis ability in fermentation of milk, which is used to enhance flavor and texture. Some healthy function ingredients, such as amino acid and biopeptide are detected in Lactobacillus helveticus fermented yogurt and cheese. Lactobacillus helveticus was selected as starter to prepare yogurt and Camembert cheese. Casein phosphopeptides (CPPs) was extracted and purified from Lactobacillus helveticus fermented yogurt and cheese.According to the rapid acidification and slime-forming capacity of Lactobacillus helveticus, the Orthogonal Array Design was used to analyze fermented milk made from different culturing condition. The result indicated the optimal culture condition was that Lactobacillus helveticus could grow well at 37℃in 11% skim milk by inoculating 3% starter. The fermented milk had good coagulation, the fitness of mouthfeel and acidity.Fresh milk and Lactobacillus helveticus were applied for making Camembert cheese. Orthogonal experiments were conducted to optimize the parameters on soft cheese quality. The optimized parameters included the dose of the starter 0.005%, Lactobacillus helveticus 0.004%, pH 5.4 and cutting size 10 mm.CPPs was studied with in yogurt and cheese. Both contained Casein Phosphopeptides. CPPs in Lactobacillus helveticus fermented milk and cheese was isolated and purified through the single factorial and orthogonal experiments. The optimal operation conditions of D-201 anion-exchange resin for purifying CPPs included the elution rate 2.50 mL/min, the feeding concentration of CPPs 3%, the concentration of eluant (HCl) 0.3 mol/L and the temperature 40℃. The ration of nitrogen/phosphors (N/P) and activity to prevent calcium precipitation were determined through pH-Stat. The N/P of unpurified CPPs was approximately 11 and the N/P of purified CPPs after was 8. The purified CPPs showed stronger activity to prevent calcium precipitation than that of the unpurified CPPs.