estimating the volatility for Safranal, Isophorone, HTCC and H2O

Since very low vapor pressures are considered in this case(Saffron volaatiles), the ideal gas equation of state is applicable and as a solution,I made the logarithm of vapour pressure plot (Plot 1) of the pure liquids as a function of temperature Po(1/T) which could help to estimate the vapour pressure of the substance at the desired temperature using Clausius-Clapeyron equation.

If we assume that in a multi component gas-liquid system, a substance is in equilibrium at temperature T and pressure P, then Raoult’s law equation for ideal liquids describes the relation between Pi , the partial pressure of the volatile i in gas phase, Xi, the molar fraction of the volatile in an oil or aqueous phase, and Po , the substance pure liquid vapour pressure in mmHg unit.1

Pi (Xi , T) = Xi Po (T)

1 Richard M.Felder ,Ronald W.Rousseau,Elementary Principles of Chemical Processes, third edition, John Wiley & Sons, Inc, New York

Methods suggesting for drying of Saffron in terms of highest possible colour and aroma yield are not unified and their efficiency has always been under debate by individuals involved in industry and research. Generally Speaking in drying of Saffron, different methods such as solar drying, room drying, oven drying and freeze drying are employed. For commercial Saffron the final water content should be at least below 12% (wb)1 according to ISO 3632. During different drying methods, changes in physical and chemical properties on Saffron take place depending on the conditions of drying process such as change in porosity2 , changes in colour, aroma, flavour and enzymatic activities.

1 International Organization for Standarization: Gene`ve, Switzerland, ISO 3632. Saffron (Crocus Sativus L.). Part 1 (Specification) and Part 2 (Test methods); 1993 – Technical document

2 Manuel Carmona,Amaya Zalacain,Jose Emilio Pardo,Eulogio Lopez,Andres Alvarruiz, and Gonzalo Luis Alonso, Influence of Different Drying and Aging Conditions on Saffron Constituents, Journal of Agricultural and Food Chemistry, 2005, 53, 3974-3979

Few words about Saffron (spice)

Saffron is the most expensive spice in the globe. It is the commercial name of dried stigmas of the autumn flowering Crocus sativus L. flowers that is mostly cultivated in Iran and other countries such as Spain, Greece, Italy, India and Morocco. It is used as a spice for its colour and flavour. The dominant amount of three major carotenoid metabolites of Crocin, picrocrocin and Safranal contributes to the known characteristics of vivid orange colour, bitter taste and aroma of saffron respectively.