Abstract: In a method of producing cocoa mass from nibs from cracked, fermented cocoa beans, nibs are used from which nibs parts of an undesired degree of fermentation have been sorted out, for example by analysis of the individual nibs pieces for fluorescence, preferably by irradiation with UV light at two different wavelengths, preferably of about 254 nm and about 366 nm with a cut-off filter at about 390 nm, the analytical results being the basis of any sorting out of separate nibs pieces, or by sorting of the cocoa beans before cracking by thickness, by density or by hardness. In this respect, the fluorescence detection method can be used for monitoring the separation.

Abstract: A test sample containing L-lysine in proteinaceous substances is reacted with a .gamma.-formyl-pyridine reagent of the general formula ##SPC1##Wherein R.sup.1 and R.sup.2 are each aliphatic carbon groups having not more than 4 carbon atoms or forming with two adjacent carbon atoms in the pyridine ring aromatic rings, in order to form the corresponding Schiff base, and the amount of reacted pyridine reagent is determined.