Hydrolyzed casein as a source of bifidus factor
z . ZBIKOWSKI and s. ZlAlKA
In the breast-feed infants about 90% of microflora present in the intestinal tract is constituted by Bi'dubacterium bifidum. Many investigators have attempted to isolate various Bzjidobacterium bijidum growth promoting factors in human milk. These substances are referred to as a bifidus factor. Cow milk, contrary to human milk, has a minimum growth promoting activity for these bacteria. According to RAYNAUD [6] these activity can be improved after hydrolysis of cow milk casein. Cow milk casein can be hydrolyzed by means of proteolytic enzymes or mineral acids. The properties of the casein bifidus factor are not well recognized and may depend on the method used for its isolation. That is why the purpose of this study has been to establish which way of casein hydrolysis yields the most promoting bifidus factor and to determine its properties.
Samples of casein bifidus factor (CBF) were obtained'by acid and proteolytic enzymes hydrolysis. Isolation of CBF by sulfuric acid (0.18 N) hydrolysis was conducted according to KEHAGIAS et al. [2]. The following proteolytic enzymes were used for casein hydrolysis: pepsin (1 : 3000) and papain ( I :350). Hydrolysis by enzymes was carried out as follows:
Pepsin hydrolysis: 500 g of casein were suspended in 5 1 of water and pH was adjusted to 3 by sulfuric acid. A suspension was heated to 37 "C and 13.5 g pepsin were added. Hydrolysis was carried out through 3 h. After that time pH was changed to 4.6 with Ca(OH),. Then hydrolyzate was heated at 80 "C for 5 min, cooled