IMPROVEMENT OF EXTRACTION METHODS AND QUALITY OF FENNEL AND ROSEMARY ESSENTIAL OILS

ABDALLAH ATEF ELSAFY;

Abstract


ABSTRACT

An efficient microwave irradiation pretreatment (MIP) method was applied to maintain high content and high quality essential oils (EO) of dry rosemary leaves and dry fennel fruits. Different times and levels of MIP were employed, the findings indicated that the oil yield increased as MIP power increased. Where, the highest yield of rosemary and fennel essential oil was obtained at 180 and 90 watts for 1 and 5 minutes, respectively, with an increment rate
14.91 and 17.14 %, respectively. In general, our data showed that although there are common increasing trend of yield of rosemary and fennel essential oils with increasing microwave irradiation power and time, the relationship was not linear. The obtained essential oils were fractionated and identified by using GC/MS technique. The main constituents of rosemary essential oil extracted by hydrodistillation only were 1,8 cineol, α-pinene and camphor, however, MIP increased the amounts of α-pinene, β-pinene, camphor and α-terpineol. Generally, MIP of rosemary oil led to disappearance of 1-octen-3-ol and limonene, simultaneously estragole, which was not present in control oil. On the other hand, methyl chavicole was the dominant compound in fennel fruits essential oil extracted by hydrodistillation only, followed by d-limonene and fenchone, however, MIP at 90 watts for 5 min. led to increase camphene, sabinene and β-pinene while, α-terpineol disappeared. Also, results ascertained that different pretreatments for both rosemary leaves and fennel fruits didn’t affect the physico-chemical properties of their essential oils compared with essential oil extracted by hydrodistillation only. Furthermore, no obvious differences were observed in an antioxidant capacity (IC50 µg/ml) of such oils obtained with hydrodistillation only and those treated with MIP method (p<0.05) with the superiority to rosemary essential oil, followed by BHT as a synthetic antioxidant agent (reference), meanwhile, fennel essential oil recorded the lowest radical scavenging activity. The antimicrobial activity purported that rosemary essential oil gave superior antimicrobial activity against S. aureus, S. cerevisiae and C. albicans where it exhibited a moderate effect against B. cereus, S. typhimurium, E. coli, A. niger and A. flavus. However, fennel fruits essential oil gave a higher antimicrobial activity against B. cereus, S. cerevisiae and C. albicans and lower activity against S. aureus, S. typhimurium, E. coli, A. niger and A. flavus. On the other hand, no significant differences were observed among all treatments used concerning the antimicrobial effect of rosemary leaves and fennel fruits essential oils. Thus, MIP could be a good method for increasing the essential oil yield with maintaining the original quality of aromatic oils.


Other data

Title IMPROVEMENT OF EXTRACTION METHODS AND QUALITY OF FENNEL AND ROSEMARY ESSENTIAL OILS
Other Titles تحسين طرق إستخلاص وجودة الزيوت العطرية للشمر والحصالبان
Authors ABDALLAH ATEF ELSAFY
Issue Date 2019

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