EFECT OF PRE-COOLING AND COLD STORAGE ON QUALITY AND QUANTITY OF SOME MEDICAL PLANTS

The object of the present study was to investigate the effect of pre-cooling and cold storage process on safe storage period, fresh weight loss, chlorophyll a and b, and volatile oil percentage and effect the optimum parameters on volatile oil components for Rosemary (Rosmarinus officinalis L.), and Spearmint (Menthaviridis Linn.) herbs. The pre-cooling process was done using cool medium at 5 ◦ C, and then the herbs were stored under three levels of storing temperatures of (2, 4 and 6 ◦ C) and relative humidity)RH) of 98 %. The obtained results from the experiment indicated that for both herbs under study should be pre-cooled at 5 ◦ C and stored at 2 ◦ C and 98 %(RH) to increase storage period, quantity and quality of oil, and to decrease the fresh weight loss for fresh consumption or marketing. Storage period at these conditions were 28 and 24 days, fresh weight loss were 1.29 and 9.98(g)/ 100 g fresh herbs, and percentage of the extracted volatile oil were 0.371 and 0.281 % for Rosemary and Spearmint herbs, respectively. Also at these conditions the quantity of volatile oil components was greater than the quantity of volatile oil if no pre- cooling was used. There was no difference found between pre-cooled and non- pre-cooled herbs and between the three storage temperatures of 2, 4, and 6 ◦ C on chlorophyll ‘a’ and ‘ b’ content for all plants under study.