The influence of natural deep eutectic solvent glyceline on the yield, chemical composition and antioxidative activity of essential oil from rosemary (Rosmarinus officinalis L.) leaves

Advances in efficient extraction of essential oils from spices and its application in food industry: A critical review

With the increase of people's awareness of food safety, it is crucial to find natural and green antimicrobial agents to replace traditional antimicrobial agents. Essential oils of spices (SEOs) are low toxicity or nontoxic, which exhibited antioxidants and antimicrobial activity according to many in vitro and in situ experiments. Spices are widely available and low cost as a plant raw material for the extraction of SEOs. This review summarized highly efficient extraction techniques for SEOs, such as physical field assisted extraction technology, supercritical fluid extraction, and biological-based techniques. Furthermore, purification of SEOs and components were also recapitulated. Purification techniques of SEOs improve their utilization value due to the increased content of bioactive components. Finally, the review concentrated on the applications of SEOs in food industry, including food preservation, food active packaging by means of films or coatings, antioxidant properties. In addition, addressing the problem of unstability of SEOs and its role to inhibit the pathogenic bacteria, the encapsulation of SEOs for use in the food industrial sectors reduces the safety risk to human health.

Selective extraction and stabilization of bioactive compounds from rosemary leaves using a biphasic NADES

Rosemary (Rosmarinus officinalis) is a natural source of bioactive compounds that have high antioxidant activity. It has been in use as a medicinal herb since ancient times, and it currently is in widespread use due to its inherent pharmacological and therapeutic potential, in the pharmaceutical, food, and cosmetic industries. Natural deep eutectic systems (NADESs) have recently been considered as suitable extraction solvents for bioactive compounds, with high solvent power, low toxicity, biodegradability, and low environmental impact. The present work concerns the extraction of compounds such as rosmarinic acid, carnosol, carnosic acid, and caffeic acid, from rosemary using NADESs. This extraction was carried out using heat and stirring (HS) and ultrasound-assisted extraction (UAE). A NADES composed of menthol and lauric acid at a molar ratio of 2:1 (Me:Lau) extracted carnosic acid and carnosol preferentially, showing that this NADES exhibits selectivity for nonpolar compounds. On the other hand, a system of lactic acid and glucose (LA:Glu (5:1)) extracted preferentially rosmaniric acid, which is a more polar compound. Taking advantage of the different polarities of these NADESs, a simultaneous extraction was carried out, where the two NADESs form a biphasic system. The system LA:Glu (5:1)/Men:Lau (2:1) presented the most promising results, reaching 1.00 ± 0.12 mg of rosmarinic acid/g rosemary and 0.26 ± 0.04 mg caffeic acid/g rosemary in the more polar phase and 2.30 ± 0.18 mg of carnosol/g of rosemary and 17.54 ± 1.88 mg carnosic acid/g rosemary in the nonpolar phase. This work reveals that is possible to use two different systems at the same time and extract different compounds in a single-step process under the same conditions. NADESs are also reported to stabilize bioactive compounds, due to their interactions established with NADES components. To determine the stability of the extracts over time, the compounds of interest were quantified by HPLC at different time points. This allows the conclusion that bioactive compounds from rosemary were stable in NADESs for long periods of time; in particular, carnosic acid presented a decrease of only 25% in its antioxidant activity after 3 months, whereas the carnosic acid extracted and kept in the methanol was no longer detected after 15 days. The stabilizing ability of NADESs to extract phenolic/bioactive compounds shows a great promise for future industrial applications.

Influence of choline chloride-based NADES on the composition of Myristica fragrans Houtt. essential oil

Natural deep eutectic solvents (NADES) have emerged as green extracting solvents in recent years. In this study, a variety of choline chloride (ChCl)-based natural deep eutectic solvents (NADES) were used as co-solvents for the hydrodistillation of nutmeg with the aim to obtain M. fragrans essential oil (EO) in higher yield and with a lower content of toxic phenylpropenoids (e.g. myristicin and safrole). The influence of ChCl-based NADES as additives in the hydrodistillation process was studied. The results showed that NADES additives improved the yield of the extracted essential oil and influenced its composition leading to a decrease in toxic phenylpropenoids. Best results were achieved by using ChCl-CA NADES ultrasound-assisted pretreatment coupled with traditional 2 ​h Clevenger hydrodistillation that increased the yield of the EO from 0.98% (traditional) to 1.41% and a decrease of the phenylpropenoids amount in the essential oil.

Unassisted and Carbon Dioxide-Assisted Hydro- and Steam-Distillation: Modelling Kinetics, Energy Consumption and Chemical and Biological Activities of Volatile Oils

The demand for more suitable eco-friendly extraction processes has grown over the last few decades and driven research to develop efficient extraction processes with low energy consumption and low costs, but always assuring the quality of the volatile oils (VOs). The present study estimated the kinetic extraction and energy consumption of simultaneous hydro- and steam-distillation (SHSD), and SHSD assisted by carbon dioxide (SHSDACD), using an adopted modelling approach. The two isolation methods influenced the VOs yield, chemical composition and biological activities, namely, antioxidant, anti-glucosidase, anti-acetylcholinesterase and anti-inflammatory properties. SHSDACD provided higher VOs yields than the SHSD at a shorter extraction time: 2.8% at 30 min vs. 2.0% at 120 min, respectively, for Rosmarinus officinalis, 1.5% at 28 min vs. 1.2% at 100 min, respectively, for Lavandula angustifolia, and 1.7% at 20 min vs. 1.6% at 60 min, respectively, for Origanum compactum. The first order and sigmoid model fitted to SHSD and SHSDACD, respectively, with R2 value at 96% and with mean square error (MSE) < 5%, where the k distillation rate constant of SHSDACD was fivefold higher and the energy consumption 10 times lower than the SHSD. The rosemary SHSD and SHSDACD VOs chemical composition were similar and dominated by 1,8-cineole (50% and 48%, respectively), and camphor (15% and 12%, respectively). However, the lavender and oregano SHSDACD VOs were richer in linalyl acetate and carvacrol, respectively, than the SHSD VOs. The SHSDACD VOs generally showed better capacity for scavenging the nitric oxide and superoxide anions free radicals as well as for inhibiting α-glucosidase, acetylcholinesterase, and lipoxygenase.