مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

EFFECT OF COLD STORAGE AND DIFFERENT PACKAGING MATERIALS ON THE QUALITY OF FRESH ROSEMARY HERB: II- EFFECT ON THE ESSENTIAL OIL PERCENTAGE AND COMPOSITION.COMPOSITION.ABSTRACT Fresh culinary herbs are one of the fastest growing markets for gourmet production on a world wide scale. Some herbs are sold fresh rather than dry because they do not retain their flavor when dried. Rosemary (Rosmarinus officinalis L.) plant is an important aromatic culinary herb. Essential oil of rosemary is considered one of the strongest natural antioxidants. A study was carried out during two successive summer seasons 2006 and 2007, at the Post Harvest Lab in the Vegt. and Floric. Dept., Fac. of Agric., Monsoura Univ. This part (II) aimed to investigate the effect of cold storage temperatures and different packaging materials on the essential oil percentage and composition of fresh rosemary herb and the changes that took place during storage until the end of their shelf life as fresh herbs. Fresh rosemary herbs were packaged in nine different packaging materials: Butter bags (P1), Cellophane bags (P2), Nylon bags (P3), Polyethylene bags (P4), Aluminum foils (P5), Aluminum plates covered with foil (P6), Aluminum plates covered with plastic film (P7), Foam plates covered with foil (P8), Foam plates covered with plastic film (P9), and then stored at (1, 3, and 5 °C) for 6 weeks. Gas Liquid Chromatography (G.L.C.) analysis was carried out in second season summer 2007 to compare between the composition of the oil of the freshly harvested herb and the of oil of herbs packaged in Aluminum plates covered with foil (the package that gave best marketability for fresh herb shown in Part 1) after one and three weeks of storage under the three cold storage temperatures. The results showed that the essential oil percentage of the herb increased with increasing the length of the storage period. Oil percentage in herbs stored at 3 °C was superior to those stored under the other two temperatures in both seasons. Herbs kept in Butter bags (P1) had maximum oil percentage until the second week of storage. Cellophane bags (P2) were the highest in the fourth week of storage, while at the fifth week of storage; Foam plates covered with foil (P8) was the highest. At the end of six weeks of storage at 3 C only Aluminum plates covered with foil (P6) and Aluminum foils (P5) were marketable in both seasons, but (P6) had higher oil percentage than (P5). GLC analysis identified 14 compounds constituted 88.8 % of the essential oil of rosemary fresh herb after harvest (control). The identified compounds included seven hydrocarbons forming 57.25 % and seven oxygenated forming 31.55 % of the total compounds. Hydrocarbons were α- pinene (11.93 %), β- pinene (7.01 %), limonene (3.01 %), ρ- cymene (10.11%), camphene (7.94 %), γ- terpinene (9.23 %), and α- terpinolene (8.02 %). Oxygenated compounds were 1,8 cineole (7.27 %), linalool (6.79 %), verbenol (1.94 %), borneol (3.83 %), thymol (4.47 %), camphor (2.3 %), and terpineol (4.95 %). The total percentage of hydrocarbons and oxygenated compounds decreased after storage compared with the control. The total percentage of each of hydrocarbons and oxygenated compounds were higher at 3°C than those at either 1 or 5 °C at the two comparable storage periods. At a storage temperature of 3°C, all hydrocarbons had higher percentages after one week of storage than after three