engleski

Antioxidant stability of medicinal plants' hydrosols during storage

In recent years, the demand for novel antioxidant agents derived from natural products is rising in the food industry. Medicinal plants such as bay laurel (Laurus nobilis L), sage (Salvia Officinalis L.) and thyme (Thymus vulgaris L.) contain a variety of bioactive molecules that contribute to the plants' antioxidant potential. While the antioxidant potential of plant extracts and essential oils has been well researched, the potential of hydrosols secondary products of hydrodistillation process, has recently raised research interest. Hydrosols consist of distillation water with small amounts of dispersed essential oils which provide them antioxidant and antimicrobial properties potentially applicable in the food industry. The aim of this study was to evaluate the antioxidant potential of hydrosols of bay laurel, sage and thyme, and their mixture (1:1:1) obtained during hydrodistillation on Clevenger apparatus, and to monitor their antioxidant stability through 28 days of storage at room temperature by DPPH Radical Scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. Bay laurel hydrosol showed the highest antioxidant activity on the first day with a value of 2000 µM of Trolox equivalents (TE) as determined by both DPPH and FRAP followed by the plant mixture (DPPH 1000 µM TE, FRAP 621 UM TE), thyme (DPPH and FRAP 370 µM TE) and sage whose antioxidant activity was at the bottom of detection level. Both FRAP and DPPH showed that the antioxidant activity of all hydrosols has gradually decreased down to approximately 50% after 28 days. Nevertheless, bay laurel hydrosol has shown the highest potential for application in the food industry, for example in minimal processing of fruits and vegetables with the goal of prolonged shelf life, since the DPPH and FRAP values were still relatively high (1000 µM TE) after 28 days.

medicinal plants, antioxidant activity, hydrosols, storage

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