Annex White book.pdf

A4.1.1.8extractsCrocine, picrocrocine and safranol determination in methanolThe quantitative determination of the characteristic componentsof saffron is carried out by absorbance measurements in metabolicsubstance extracts that dissolve appropriately in the following wavelengths:· 440 nm for crocine· 318 nm for safranol· 257 nm for picrocrocineWe use as blank the same diluent, existing in the extract. The absorbancemeasurements are performed with a double ray UV Vis spectrophotometer.The quantitative indications are calculated in respectto the A values (1%, 1 cm). In accordance with the law, the lowest absorptionlimit is 0,44 for 440 nm solution extract that derives from thetreatment of 0,10 g saffron with 5 ml water after diluting 1 ml of theinitial solution up to 500 ml. The absorption values in 440 nm of waterextracts produced in San Gavino Monreale, vary between 0,96 and 1,13.The quantitative values of absorption measurements at 440 mm of themetabolic extracts show that the crocine content, rendered in crocine1, varies between 17,45% and 19,27%. The quantitative data regardingpicrocrocine vary between 24,54% and 30,09%.A4.1.2 TECHNIQUES BASED ON ISO 3632ISO (International Organization for Standardization) has establishedthe technical specification ISO/TS 3632 2003 (parts 1 and 2,regarding saffron specifications and testing methods respectively). TheISO standard for saffron has been altered three times (1980, 1993 and2003) since its initial creation in 1975. The text of the ISO standardhas been consecutive improved and adapted to the international tradedemands of the spice. The 1980 issue defined three commercial categorieswith flower residue tolerance between 7 and 20%. Concerningchemical terms, the maximum admissible humidity was at 14% for saffronthreads and at 8% for saffron powder. Minimum values regardingcrude ashes content, cold water diluted extract and nitrogen contentwere also defined as well as a minimum value for coloring power thatwere measured through absorbance measurements at 440 nm. Theaqueous solution was the afloat received before filtration and duringdetermination in cold water soluble extract according to the proceduredescribed in ISO 941:1980.The next issue, the one of 1993, defined the commercial categoriesanew and standardized the parameters defining the international trade145