Electrochemical sensor detecting free sulfhydryl groups: evaluation of milk heat treatment.
We describe a new and rapid method for the evaluation of reactive sulfhydryl groups in whey proteins obtained after precipitation of casein by acetic acid at pH 4.6. The procedure is based on the use of a wire tungsten electrode operating at -0.2 V versus saturated calomel electrode in flow injection analysis. The method was applied to raw milks and to commercial pasteurized and UHT milks. Results showed that the tungsten electrode constituted a robust amperometric sensor that could be used to differentiate milks that underwent different heat treatments. The decrease of thiol content in the whey proteins from samples was in agreement with the whey protein content found by HPLC. The procedure is suitable for on-line quality control of heat-treated milks.
Cosio
M S
MS
Department of Food Science and Technology, University of Milan, Italy.
Mannino
S
S
Buratti
S
S
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003124:Colorimetry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D005511:Food Handling / Q000592:standards; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis* / Q000737:chemistry; D011786:Quality Control; D015203:Reproducibility of Results; D013438:Sulfhydryl Compounds / Q000302:isolation & purification*; D013997:Time Factors; D000067816:Whey Proteins
D008894:Milk Proteins; D013438:Sulfhydryl Compounds; D000067816:Whey Proteins