Microwave-Assisted Extraction of Bioactive Compounds from Lentil Wastes: Antioxidant Activity Evaluation and Metabolomic Characterization

Abstract

The recovery of industrial by-products is part of the zero-waste circular economy. Lentil seed coats are generally considered to be a waste by-product. However, this low-value by-product is rich in bioactive compounds and may be considered an eco-friendly source of health-promoting phytochemicals. For the first time, a sustainable microwave-assisted extraction technique was applied, and a solvent screening was carried out to enhance the bioactive compound content and the antioxidant activity of green and red lentil hull extracts. With respect to green lentil hull extracts that were obtained with different solvents, the aqueous extract of the red lentil seed coats showed the highest total phenolic and total flavonoid content (TPC = 28.3 ± 0.1 mg GAE/g dry weight, TFC = 1.89 ± 0.01 mg CE/100 mg dry weight, respectively), as well as the highest antioxidant activity, both in terms of the free radical scavenging activity (ABTS, 39.06 ± 0.73 mg TE/g dry weight; DPPH, IC50 = 0.39 μg/mL) and the protection of the neuroblastoma cell line (SH-SY5Y, IC50 = 10.1 ± 0.6 μg/mL), the latter of which has never been investigated so far. Furthermore, a metabolite discovery analysis was for the first time performed on the aqueous extracts of both cultivars using an HPLC separation which was coupled with an Orbitrap-based high-Resolution Mass Spectrometry technique.

Consumers left at the mercy of chefs for potency, consistency, safety and regulation—the edibles industry of cannabinoids—A critical review

“…de Vita et al (2019) compared different methods for cannabinoids by investigating the temperature, solvent and time and found that increase in temperature and time caused 4 times higher than the extraction methods using ethanol at 90 °C for 15 min. Pan et al (2021) also used microwave-assisted extraction to extract the Osmanthus fragrant flower and can achieve maximum antioxidant activity with a short time (59.03 s), solid-liquid ratio (31.14 mL g À1 ), and power of only 497.12 W. The extraction of bioactive compounds to guarantee sustainability and eco-friendly procedure was investigated by Cavalluzzi et al (2022), showing the highest total phenolic, flavonoid content and antioxidant activity extraction methods using the microwave-assisted extraction method compared with the solvent extraction methods. These studies show the safe and eco-friendly to replace the conventional solvent extraction process, which is time consuming.…”

Curcumin: Overview of Extraction Methods, Health Benefits, and Encapsulation and Delivery Using Microemulsions and Nanoemulsions

“…Curcumin can be extracted using either conventional or advanced techniques. Since conventional extraction methods such as solvent extraction and Soxhlet extraction [7] require a considerable amount of time, organic solvents, cooling water [40], and energy [41], several researchers have applied novel extraction methods such as ultrasound-assisted extraction [42], microwave-assisted extraction [43], enzyme-assisted extraction [44], supercritical fluid extraction [45], and pressurized liquid extraction [46] (Figure 3). Regardless of the technique used, the preparation of the raw material prior to processing and the selection of the best parameters have a significant impact on the efficacy of the extraction technique and the quality of the extract.…”