Valorization of wastewater from table olives: NMR identification of antioxidant phenolic fraction and microwave single-phase reaction of sugary fraction

The table olive industry is producing a huge amount of wastewater, which is a post-processing cost and an environmental concern. The present study aims to valorize this processing by-product to obtain a value-added product, thereby enhancing resource efficiency and contributing to achieving sustainable development goals (SDGs). In this sense, a chemical reaction-based platform was developed to obtain valuable components, such as levulinic acid (LA) and 5-hydromethylfurfural (HMF). The products were then analyzed using NMR identification of the antioxidant phenolic fraction and microwave single-phase reaction of the sugary fraction. According to the results, the highest concentration of phenolic compounds does not correspond to the sample directly obtained from NaOH treatment (S1), indicating that water washing steps (S2-S5) are fundamental to recover phenolic substances. Moreover, glucose was presented in the sugary fraction that can be transformed into levulinic acid by a single-phase reaction under microwave irradiation. The information provided in this manuscript suggests that the wastewater from the olive processing industry can be valorized to obtain valuable products

Data for: Ohmic accelerated steam distillation of essential oil from lavender: energy consumption and physicochemical properties of the extract

This GC-MS graph compares the compositions of the extracted essential oils through SD and OASD

Data for: Environmental hazard of ohmic-assisted hydrodistillation: a critical study on a negative aspect of this selective and economic extraction technique

These are the ICP-MS and GC-MS conditions. The GC-MS file contains the raw graphs as well

Data for: Ohmic accelerated steam distillation of essential oil from lavender: energy consumption and physicochemical properties of the extract

This GC-MS graph compares the compositions of the extracted essential oils through SD and OASD.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Ohmic-assisted hydrodistillation technology: A review

Volumetric heating techniques such as ohmic heating have emerged as alternatives to conventional processing methods for diverse applications in the food industry. One of the novel applications of ohmic heating is ohmic-assisted hydrodistillation (OAHD), which utilizes the volumetric heating benefits to overcome traditional distillation shortcomings. This technique proffers benefits such as saving time and energy and has gained increasing interest as a preferred approach for ethanol distillation and essential oil extraction from various plant materials. Scope and approach This paper reviews the principles and current applications of OAHD. The effects of OAHD on process time, energy consumption, and distillate quality are discussed. Considerations for industrial application of OAHD are highlighted and its salient drawbacks are also taken into account. Key findings and conclusions Advantages of OAHD over conventional distillation include high thermal efficiency, short processing time and reduced operational cost. Further research on safety and sustainability along with economic study are prerequisites for commercial application of this technology

Data for: Environmental hazard of ohmic-assisted hydrodistillation: a critical study on a negative aspect of this selective and economic extraction technique

These are the ICP-MS and GC-MS conditions. The GC-MS file contains the raw graphs as well.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Accelerated texture softening of some root vegetables by Ohmic heating

Effects of different thermal processing methods (Ohmic heating, high and low power, microwave and conventional heating) on textural properties of cylindrical pieces of root vegetables of carrot, red beet and golden carrot were investigated and compared with conventional and microwave processes. The samples were subjected to different processing methods and textural parameters of the processed samples were analyzed using texture profile analysis (TPA) at different processing times. Texture parameters-processing time data were fitted into a previously suggested equation and texture softening rate (K) and residual constant (A) values were calculated. From the K and A values it can be concluded that not only Ohmic heating resulted in greater softening rates but also the final hardness of the samples treated by Ohmic heating was significantly lower than those of other samples treated by either conventional or microwave methods. Negative correlations were found between texture hardness and weight loss of all samples undergone different processing methods

Multiple effect concentration of ethanol by ohmic-assisted hydrodistillation

Our previous work on ethanol distillation by ohmic-assisted hydrodistillation (OAHD) successfully concentrated ethanol from 10 to 50% (v/v). In this work, two additional concentration steps were conducted using the 50% (v/v) product obtained from the first concentration stage at a constant wattage of 168 W using the same OAHD device. The second distillation step resulted in a product with ethanol concentration of 76% (v/v) and the third step yielded ethanol concentration of 84% (v/v). Results were compared to conventional hydrodistillation (HD), and were indicative that OAHD reduces one third of energy cost in ethanol distillation process. Not only was OAHD superior to HD in terms of time and energy consumption, but also resulted in higher ethanol concentrations than HD after the third step of distillation: 84.3 ± 0.3% vs. 82.5 ± 0.5%, respectively. OAHD also showed better process control and was able to stop the distillation process faster than HD. In both second and third distillation steps, the time required to stop the process with OAHD (1 min) was shorter than for HD process (10 min). The findings of this study further confirm our previous work, and reveal that this emerging distillation technique has the potential of yielding high concentrations of ethanol from dilute alcoholic solutions in a more economical and environmental friendly way

Ohmic-assisted hydrodistillation: A novel method for ethanol distillation

Distillation is one of the most time and energy consuming steps in bioethanol production and some food operations. Ohmic-assisted hydrodistillation (OAHD) is a new proposed extraction method which uses the advantages of ohmic heating and has been used for essential oil separation. In this study, an OAHD device was designed and developed for ethanol distillation using titanium electrodes. Results of the OAHD process were compared to those of traditional hydrodistillation (HD) at constant wattage of 168 W for 3 L of 10% (v/v) ethanol solution containing 0.5% (w/v) sodium chloride as the electrolyte. Results indicated that the required energy for separation of ethanol in OAHD was 33% less than HD. In addition, OAHD completed the distillation process in 75.2 ± 2.2 min while HD required 108.4 ± 5.3 min. The concentrations of ethanol in the final distilled product from both methods were similar (47.3% ± 3.2 for OAHD vs. 50.0% ± 2.6 for HD). Interestingly, in OAHD, process control is faster and distillation can be stopped in seconds and consequently, less unwanted distillate in comparison to HD (0.05% ± 0.01 and 2.28% ± 0.03 of total distilled product, respectively). The findings of this study introduce OAHD as a potentially economical and environmentally friendly method for the ethanol distillation process

Comparison of ohmic-assisted hydrodistillation with traditional hydrodistillation for the extraction of essential oils from Thymus vulgaris L.

Ohmic-assisted hydrodistillation (OAHD) is an advanced hydrodistillation (HD) technique utilizing ohmic heating process and could be considered as a novel method for the extraction of essential oils. One of the major problems with traditional methods is long extraction time. OAHD of essential oils from the aerial parts of Thymus vulgaris L. (common thyme) was studied and the results were compared with those of the conventional HD. The results showed that OAHD method had the extraction time of 24.75 min while this value was about 1 h for HD. Scanning electron micrographs of thyme leaves showed a sudden eruption of essential oil glands and their surrounding area for OAHD samples. GC-MS analysis did not indicate any noticeable changes in the compounds of the essential oils obtained by OAHD in comparison with HD. Results of this study introduced OAHD as a green technology because of less energy required per ml of essential oil extraction. Industrial relevance: The quality and quantity of essential oils extracted from herbs and other raw materials are affected by the extraction method. In this research ohmic-assisted hydrodistillation (OAHD) was used as an advanced and novel hydrodistillation (HD) technique and compared with traditional hydrodistillation in extraction of essential oils from the aerial parts of Thymus vulgaris L. (common thyme). OAHD method was quicker, more economical and environmentally friendly than hydrodistillation method. The results of this study introduced OAHD as a green technology