Importance Of Essential Oil And Mucilage Extraction

2. Materials and methods

Essential oil and mucilage extraction and purification

For essential oil extraction, dry plant materials of rosemary distilled within 24 h in a steam distiller with an aqueous phase recycling system, using a plant material: water ratio of 2:1. The distillation time was about 2 h, and the oil obtained was separated from the aqueous solution and dried by treating with anhydrous Na2SO4. Each essential oil was transferred into a dark glass flask filled to the top and kept at a temperature of 4 °C until used (Meepagala et al., 2002). Also for mucilage extraction, Cactus stems were removed skin and cubed (1 cm3). Samples were homogenised (20% w/v) in distilled water. The slurry was centrifuge for 10 min at 4,500 rpm and the supernatant precipitated in ethanol and finally dried (Sáenz et al., 1992).

Preparation of liposomal oil

Multilamellar vesicles were prepared according to the thin film hydration method (Gortzi et al., 2006). Lipid solution was prepared by dissolving 5 mg/ml of phosphatidylcholine, 1 mg/ml cholesterol and 0.1 mg/ml essential oil in 3 mg/ml chloroform. Phosphatidylcholine from fresh egg yolk and chloroform were obtained from Sigma Chemicals Company Ltd. (St. Louis, MO, USA). Cholesterol was purchased from Fluka (Buchs, Switzerland). 5.0 ml from the lipid solution was introduced in a 100 ml round-bottomed flask. The solvent was evaporated in a Heidolph Laborota rotary evaporator (model 4000; Heidolph Laborota, Schwabach, Germany), at 35-40 °C, under reduced pressure (13-14 mm Hg). The obtained dry lipid film was hydrated with 5 ml distilled water. The mechanical stirring of the lipids in aqueous medium was performed with the rotary evaporator equipment at 37 °C and by manual stirring in the wat...

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...Shimadzu UV-Vis 1601 spectrophotometer. The standard curve was established using gallic acid.

Microbiology

For the microbiological analysis, banana slices (10 g) were removed aseptically from each package and were transferred into a sterile plastic package to which 90 ml Ringer’s sterile solution was added. The sample and the ringer solution were blended for 60 s by using a stomacher, 400 Circulator (Seward Ltd, Thetford, UK). The Portuguese standard methods, EN ISO 4833 (ISO, 2003), was followed for counting total aerobic plate count (TPC).

Statistical analysis

The research was established according to complete randomised design with three replicates. All data obtained from the trial were analysed using analysis of variance (ANOVA) and using the computer software SPSS, version 15.0 (SPSS Inc., Woking, UK). Means were compared using the LSD test at the P<0.05 level.