Ultrasound-Assisted Extraction of Lavender (Lavandula angustifolia Miller, Cultivar Rosa) Solid By-Products Remaining after the Distillation of the Essential Oil

Federica Turrini,Giorgia Triglia,Margherita Beruto,Luciano Mela,Paolo Curir,Raffaella Boggia,Fernando Monroy,Paola Zunin

doi:10.3390/app11125495

Abstract

FINNOVER is an EU Interreg-Alcotra project that aims to bring new perspectives to floriculture enterprises by recovering useful bioproducts from the waste produced during processing of several aromatic species. In this study, a new operation strategy to recover lavender (Lavandula angustifolia Mill.) solid by-products remaining after the extraction of the essential oil was developed. Pulsed ultrasound-assisted extraction was employed as a sustainable and eco-compatible technology to extract, in a very short time (10 min), this agricultural waste using a food-grade solvent (a mixture of ethanol/water). All the extracts obtained from both flower and leaf waste and flower-only residues, exhibit a promising total phenolic content (38–40 mg gallic acid/g of dry waste), radical scavenging activity (107–110 mg Trolox/g of dry waste) and total flavonoid content (0.11–0.13 mg quercetin/g of dry waste). Moreover, the chromatographic analysis of these extracts has shown that this overlooked agriculture waste can represent a valuable source of multifunctional compounds. Particularly, they exhibit a content of polyphenols and flavonoids up to 200 times higher than the corresponding leachate, and they are a valuable source of gentisic acid (1.4–13 mg/g dry waste) representing a new low-cost ingredient usable in different fields (i.e., cosmetic).

Highlights

The total solid waste (TW) composed from flower and leaf residues remaining after the distillation of essential oil, was supplied to the residues remaining after the distillation of essential oil, was supplied to the food chemis-food chemistry of the University
There is little information of flavonoid variation at the cultivar level, our results suggest that pulsed ultrasound-assisted extraction (PUAE) of distillation by-products may contribute to lavender characterization at this level
The solid by-products remaining after the traditional distillation of lavender essential oil constitute an interesting source of antioxidant compounds such as polyphenols and flavonoids, whose recovery could be performed as a first step in their valorization before using the remaining lignocellulosic biomass for other purposes

Summary

Introduction

The solid by-products remaining after the distillation of lavender, which are still little studied in scientific literature, are taken into account as a potential and still underutilized source of bioactive compounds to be valorized. These solid wastes, sometimes called “distilled straws of lavender” are lignocellulosic-rich materials, which have been proposed as an interesting source to be converted into biofuel [1]. Could represent a useful first step towards its utilization as an economic resource still to be exploited This recycling possibility has been evaluated inside a European research project called Finnover. The management of waste deriving from agricultural and food processing is one of the main topics of the project, offering new perspectives to floriculture enterprises by recovering useful bioproducts from the waste produced during the distillation of essential oils from lavender and other aromatic species

Methods

Results

Conclusion