Résumé:
This study was conducted in order to enhance the lemon peel (Citrus limon) by using their essential oil as a natural agent for preservation and aromatization in cream in order to diversify the types of
existing cream on the market.
This essential oil was extracted by hydroditillation, extraction yield was 0,89 ± 0,09%. The antioxidant activity of the extracted essential oil was studied by the DPPH° test, this free radical has been effectively reduced, compared to vitamin E. These results were confirmed by the test of β- carotene bleaching.
The study of antimicrobial activity of essential oil of C. limon showed that two tested bacteria are resistant against the effectiveness of the oil, resulting in very high MICs (4% and > 8%). Regarding yeast strains isolated and tested Debaryomyces sp. and Rhodotorula sp., they have some sensitivity
to the effect of essential oil, characterized by CMI respectively 0,25% and 0,5%. The other two strains Zygosaccharomyces sp1 and Zygosaccharomyces sp2, were resistant, their MICs are respectively in the order of 1% and > 4%.
The various tests on the formulation of the added essential oil of C. limon creams were tested by developing three fresh creams with concentrations of 0,125%, 0,25%, 0,5%. Characteristics are conforms to standard. The results of physicochemical and microbiological analyzes prepared fresh cream after opening the package, show that the presence of the essential oil at low concentrations does not limit microbial spoilage. The evaluation of the oxidative stability by Schaal test indicates that the fresh cream with essential oil of C. limon are more resistant than the control opposite the forced oxidation.
Sensory analysis show that the incorporation of essential oil in the cream, at concentrations of 0,125% and 0,25%, involves no significant difference (p > 0,05) in terms of flavoring, and make products which are classified in same order than the control. Only the rate of incorporation of the essential oil of 0,5% significantly downgraded the product compared to the control in the third row, which has led to changes in smell and flavor while the texture, color and taste are unchanged. The principal component analysis (PCA) showed a negative correlation (r = - 0,998) between the levels of incorporation of the essential oil and the aroma of raw milk, and a positive correlation (r = 0,956) with the color yellow.
