Investigation of the Antioxidant Behavior of Air- and Freeze-Dried Aromatic Plant Materials in Relation to Their Phenolic Content and Vegetative Cycle

• Published in: Journal of agricultural and food chemistry Vol. 56; no. 14; pp. 5743 - 5752
• Main Authors: Papageorgiou, Vassiliki, Mallouchos, Athanasios, Komaitis, Michael
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 23-07-2008
• Subjects: aerial parts; air drying; antioxidant activity; antioxidants; Antioxidants - analysis; Aroma and flavouring agent industries; Aromatic plants; bay (herb); Biological and medical sciences; chemical analysis; Chemical Composition of Foods/Feeds; Chromatography, High Pressure Liquid; Desiccation - methods; fennel; flavonoids; Flavonoids - analysis; Foeniculum - chemistry; Foeniculum vulgare; Food engineering; Food industries; Freeze Drying; Fundamental and applied biological sciences. Psychology; General aspects; Greek bay; harvest date; Laurus - chemistry; Laurus nobilis; marjoram; Mentha; Mentha - chemistry; Mentha viridis; mint; Odorants - analysis; Origanum - chemistry; Origanum majorana; phenolic compounds; phenolics; Phenols - analysis; Plant Development; Plant Leaves; Plants - chemistry; rosemary; Rosmarinus - chemistry; Rosmarinus officinalis; RP-HPLC; spearmint; RP-HPLC; rosemary; marjoram; fennel; Greek bay; freeze-drying; Aromatic plants; air drying; spearmint; antioxidant activity; phenolics; Freeze drying; Vegetables; Air drying; Materials; Spice; HPLC chromatography; Air; Antioxidant; Cycle; Fennel; Marjoram; Phenols; Rosemary
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf8009393

The total phenolic and flavonoid content of the aerial parts of five aromatic plants harvested at different periods was estimated, and their antioxidant capacity was evaluated. Major phenolic compounds present in their extracts were determined by RP-HPLC. The results demonstrated different amounts of total phenolic compounds and various degrees of antioxidant activity depending on the plant species, the time of harvest, and the drying method employed. Extracts from air-dried Mentha viridis L., Origanum majorana L., and Rosmarinus officinalis L. demonstrated the greatest efficacy during the flowering stage, in which the identified flavonoids were found in significantly higher amounts, whereas phenolic acids were found in their lowest concentration. Extracts from air-dried Laurus nobilis L. and Foeniculum vulgare Mill were less efficient in terms of antioxidant activity, with the highest values being observed during the early fruiting stage. This stage was characterized by the lowest flavonoid content and high phenolic acid content, except for L. nobilis L. extracts. Overall, the amount of identified phenolic acids did not vary considerably within the investigated year. The total phenolic concentration in all plant extracts decreased significantly when freeze-dried rather than air-dried samples were used. The HPLC analysis further supported the above for most of the phenolic compounds present in the extracts, except for hydroxybenzoic acids, which were better retained during the freeze-drying process.