Determination of protein and casein in milk by fourth derivative UV spectrophotometry

被引:34
作者
Lüthi-Peng, QQ [1 ]
Puhan, Z [1 ]
机构
[1] Swiss Fed Inst Technol, Inst Food Sci, Lab Dairy Sci, CH-8092 Zurich, Switzerland
关键词
milk protein and casein determination; fourth-order derivative spectroscopy;
D O I
10.1016/S0003-2670(98)00823-X
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
The aim was to develop a simple and rapid method for determination of milk protein in general, and casein content in particular, in milk without involving preparation procedures such as skimming and casein precipitation. Fresh raw milk samples were diluted with 6 M guanidine-HCl buffer before spectroscopic scanning. The total protein and casein contents of 45 milk samples determined by this method were not statistically significantly different from the values obtained by the reference method based on Kjeldahl determination of N (p < 0.05). By using fourth derivative UV spectrophotometers, the determination of total protein and casein content in milk can be achieved directly in a single run. Treatments of milk such as heating, homogenization, preservation or hydrolysis with protease had no influence on the accuracy of protein determination in milk by this method. The accuracy of determination with 0.03% total protein and 0.04% casein for the reference method could not be achieved under the condition used, due to the effect of high dilution rate. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:227 / 234
页数:8
相关论文
共 18 条
[1]   2ND-DERIVATIVE SPECTROSCOPY OF PROTEINS - METHOD FOR QUANTITATIVE-DETERMINATION OF AROMATIC AMINO-ACIDS IN PROTEINS [J].
BALESTRIERI, C ;
COLONNA, G ;
GIOVANE, A ;
IRACE, G ;
SERVILLO, L .
EUROPEAN JOURNAL OF BIOCHEMISTRY, 1978, 90 (03) :433-440
[2]   QUANTITATION OF TRYPTOPHAN AND TYROSINE RESIDUES IN PROTEINS BY 4TH-DERIVATIVE SPECTROSCOPY [J].
BRAY, MR ;
CARRIERE, AD ;
CLARKE, AJ .
ANALYTICAL BIOCHEMISTRY, 1994, 221 (02) :278-284
[3]  
CANTOR CR, 1980, BIOPHYSICAL CHEM 2
[4]  
Creighton T. E., 1983, PROTEINS STRUCTURES, P1
[5]  
DEJONG EAM, 1995, 111692NL NIZO
[6]  
El-Din MZ, 1993, INT DAIRY J, V3, P141, DOI 10.1016/0958-6946(93)90013-P
[7]  
Havel H. A., 1996, SPECTROSCOPIC METHOD
[8]  
IDF, 1964, 29 IDF
[9]  
*IDF, 1962, 20 IDF
[10]   INTER- + INTRAMOLECULAR INTERACTIONS OF ALPHA-LACTALBUMIN .I. APPARENT HETEROGENEITY AT ACID PH [J].
KRONMAN, MJ ;
ANDREOTTI, RE .
BIOCHEMISTRY, 1964, 3 (08) :1145-&