HYDROLYSIS AND LOSS OF EXTRACTABILITY OF PROTEINS DURING RIPENING OF IBERIAN HAM

To elucidate the extent of the hydrolysis and loss of extractability o f protein during the traditional ripening of Iberian ham, the evolutio n during processing of non-protein nitrogen (NPN) and protein fraction s soluble in 0.03 M pH 7.1 phosphate and 1.1 KI + 0.1 m phosphate pH 7 .4 buffers and 6 M urea was followed from Semimembranosus and Biceps f emoris muscles. The NPN steadily increased during processing, showing maximum intensity at salting and drying. Electrophoretic study of the proteins extracted, and microscopical examination of the pellet obtain ed after consecutive extractions with the above buffers, revealed that hydrolysis and insolubilization are more intense in myofibrillar than in sarcoplasmic proteins. Protein aggregation involves mainly the myo fibrillar fraction, and occurs during the first stage of processing.