Dynamic performance of optimized microwave assisted extraction to obtain Eucalyptus essential oil: energy requirements and environmental impact

The dynamic performance of a microwave-assisted extraction (MAE) was studied during the extraction of eucalyptus essential oil. The effect of different process variables such as solid/liquid ratio (1:1, 1:3, or 1:5), stirring speed (0, 200, or 400 rpm), and power microwave output (360, 450, or 540 W) on obtained yield, energy requirements and environmental impact were assessed. The maximum yield was 1.26 ± 0.01% and the steam generation velocities between 4.8 and 8.8 g/min favor the extraction. In terms of environmental impact, the lowest EI99 value obtained was 6.93 ± 0.1 mPT/g. A multi-response optimization was performed to identify the operating conditions that maximize yield, while minimize energy requirements and environmental impact. Temperature dynamics and extraction kinetics were fitted to a second-order transfer function model, aimed to evaluate the role of heating patterns on the process performance. Finally, a controlled temperature experiment was carried out under the optimal conditions.

Impact of Eutectic Solvents Utilization in the Microwave Assisted Extraction of Proanthocyanidins from Grape Pomace

The extraction of proanthocyanidins (PACs), despite being an important and limiting aspect of their industrial application, is still largely unexplored. Herein, the possibility of combining eutectic solvents (ESs) with microwave assisted extraction (MAE) in the extraction of PACs from grape pomace (GP) is explored, aiming to improve not only the extraction yield but also the mean degree of polymerization (mDP). The combination of choline chloride with lactic acid was shown to be the most effective combination for PACs extraction yield (135 mgPAC/gGP) and, despite the occurrence of some depolymerization, also enabled us to achieve the highest mDP (7.13). Additionally, the combination with MAE enabled the process to be completed in 3.56 min, resulting in a considerably reduced extraction time.

Optimization of Anthocyanin Extraction from Cockspur Coral (Erythrina Crista-Galli L.) Petals with Microwave-Assisted Extraction (MAE) using Response Surface Methodology

Cockspur coral (Erythrina crista-galli L) petals are flowers that contain anthocyanins and active compounds of flavonoids and tannins. This study aims to determine the optimum conditions for the anthocyanin extraction process of cockspur coral petals using Microwave-Assisted Extraction (MAE), analyzed through the Response Surface Method (RSM). This process uses ethanol-hydrochloric acid solvents and a Box-Behnken experimental design involving three factors, namely the solvent ratios (w/v) (1:5, 1:15, and 1:25), microwave powers (300, 450, and 600 watts), and extraction times (3, 9, and 15 minutes). As a result, the second-order polynomial model was enhanced and sufficient to explain the variation of the data that denoted the significant correlation with the independent variables and the response. Derringer's desired function methodology was used for optimizing studies and generated ideal conditions for each or combined an independent variable. The optimum anthocyanin extract of 5.82 mg/L was obtained at a power condition of 325,5 Watts, an extraction time of 3.05 minutes, and a solvent ratio of 20.5. Meanwhile, the operating conditions at a power of 310.8 Watts, a time of 14.94 minutes, and a solvent ratio of 24.96 resulted in the optimum color intensity (IC) of 1040.26. In the meantime, the optimum antioxidant activity was obtained at a power of 585.97 Watts, a time of 4.93 minutes, and a solvent ratio of 5.43 with IC50 of 0.115.

Comparison of Microwave-Assisted Extraction to Soxhlet Extraction of Mango Seed Kernel Oil using Ethanol and n-Hexane as Solvents

Mango seed kernel oil was extracted by Soxhlet Extraction (SE) and Microwave-Assisted Extraction (MAE) with ethanol and n-hexane as extraction solvents. To optimize the extraction condition for SE, the temperature was set to 90°C for ethanol and 80°C for n-hexane with varying solvent-to-feed ratios (S/F ratio) of 75/12, 75/10, and 60/6 mL/g. As for MAE, the same S/F ratios were considered. Extraction was done for 5, 10, and 15 minutes with microwave power levels of 120 and 240 W. It was found out that the highest yield per extraction process for SE was: 18.00±0.25 % and 9.38±2.03 % using ethanol and n-hexane, respectively; and 6.69±0.05 % and 4.68±0.06 %using ethanol and n-hexane, respectively for MAE. It was also noted that MAE, with the microwave power level of 120 W has less extraction time for about 15 minutes as compared to SE of 8 hours. Also, the best S/F ratio in this study is 60/6 for all processes. In oil quality determination, the oil extracted was examined through several tests such as FTIR, GC-MS, acid value, % FFA, iodine value, saponification value, and melting point. It was noted that oil extracted in ethanol has a better yield compared to that of n-hexane but the oil extracted using n-hexane would provide superior quality.

Assessment of Total Phenolic Content and Antioxidant Activity Potential of Clementine Extract Obtained by Microwave Assisted Extraction Method

Citrus peels are known as rich source of bioactive compounds. Therefore, the establishment of an appropriate and innovative extraction method is a major interest to the food processing industry. The aim of this work is to assess the total phenolic content (TPC) and antioxidant activity (AA) of peels extracts prepared from five Moroccan clementine varieties. Extracts were prepared with microwave-assisted extraction (MAE) technique using acetone and methanol solvents. The evaluation of the antioxidant activity was performed by DPPH and ABTS- free radical scavenging. The extraction conditions had significant effects on total phenolic content (TPC) and antioxidant activity (AA). In fact, the highest TPC amount of clementine varieties (730.850±0.004mg GAE/100g DM) was obtained with acetone solvent for the Sidi Aissa variety. Regarding antioxidant activity, results with DPPH method showed an important antiradical and antioxidant activities for Sidi Aissa variety with methanol solvent (46.30± 1.01%) . However, ABTS method showed a good antioxidant activity for Ain Taoujdat with methanol solvent (3.02 mg/100g DM). This work provided to study the biochemical quality of Moroccan clementine extracts obtained by two microwave-assisted extraction processes in order to investigate further industrial potential uses in agro-food and pharmaceutical industries