Sustainable green extraction of anthocyanins and carotenoids using deep eutectic solvents (DES): A review of recent developments.

Recently, deep eutectic solvents (DES) have been extensively researched as a more biocompatible and efficient alternative to conventional solvents for extracting pigments from natural resources. The efficiency of DES extraction for the anthocyanin and carotenoid can be enhanced by microwave-assisted extraction (MAE) and/or ultrasound-assisted extraction (UAE) techniques. Apart from the extraction efficiency, the toxicity and recovery of the pigments and their bioavailability are crucial for potential applications. A plethora of studies have explored the extraction efficiency, toxicity, and recovery of pigments from various natural plant-based matrices using DES. Nevertheless, a detailed review of the deep eutectic solvent extraction of natural pigments has not been reported to date. Additionally, the toxicity, safety, and bioavailability of the extracted pigments, and their potential applications are not thoroughly documented. Therefore, this review is designed to understand the aforementioned concepts in using DES for anthocyanin and carotenoid extraction.

Utilization of natural deep eutectic solvents and ultrasound-assisted extraction as green extraction technique for the recovery of bioactive compounds from date palm (Phoenix dactylifera L.) seeds: An investigation into optimization of process parameters.

The green extraction of bioactive compounds from date seeds was investigated using seven natural deep eutectic solvents (NADES) coupled with ultrasound-assisted extraction (UAE). The seven NADESs mainly consisted of choline chloride as hydrogen bond acceptors (HBA) and four sugars, two organic acids, and one polyalcohol as hydrogen bond donors (HBD) were utilized in this study. When the extraction efficiency of the NADESs was compared to that of the conventional solvents, all the NADESs showed superior bioactive compounds recovery efficacy. The lactic acid-based NADES had the highest extraction efficiency and was further optimized using the response surface method and Box-Behnken design. A four-factors including extraction time (10, 20, and 30 min), ultrasound amplitude (70, 80, and 90 %), % NADES content (30 %, 50 %, and 70 %) and solid-to-solvent ratio (1:30, 1.5:30, and 2:30 g/ml) each at three levels (-1, 0 and 1) using Box-Behnken design was applied. The % NADES content and the solid-to-solvent ratio were the major factors influencing the extraction efficiency of the total phenolic content (TPC) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The optimum extraction conditions included an extraction time of 15 min, ultrasound amplitude of 90 %, % NADES content of 70 % and solid-to-liquid ratio of 1:30 g/ml. The experimental values for TPC and DPPH at optimum extraction conditions were 145.54 ±â€¯1.54 (mg GAE/g powder) and 719.19 ±â€¯2.09 (mmol TE/g powder), respectively. The major phenolic compounds observed in the date seeds extracted using ChCl-LA were 3,4-dihydroxybenzoic acid, catechin and caffeic acid. This study reveals that the extraction of date seeds with NADES in combination with UAE technique was able to recover significantly higher amounts of phenolic compounds which could find useful applications in the food, pharmaceutical, and cosmetics industries.

Microencapsulation of Moringa oleifera leaf extracts with vegetable protein as wall materials.

Moringa oleifera, often referred to as 'miracle tree' contains high amount of bioactive nutrients and dietary antioxidants, which help in ameliorating oxidative stress and degenerating diseases. However, the bioactive compounds are highly susceptible to degradation, and this may decrease the antioxidants activity present in M. oleifera. To prevent these limitations, the utilisation of microencapsulation technique is of necessity. This study investigated the effect of two vegetable proteins: soy protein isolate and pea protein isolate as wall materials for M. oleifera leaf extracts encapsulation by spray drying technique. Three inlet air temperatures (140, 160, and 180 ℃) and two different formulations of core:wall material ratios (1:4 and 1:9, w/w) were studied. The total phenolic contents, antioxidant activity, microencapsulation yield, morphology, colour, tapped and bulk densities, particle size, and storage stability of M. oleifera microcapsules were analysed. Moringa microencapsulates with pea protein isolate had better powder quality than Moringa microencapsulates with soy protein isolate considering its significant higher particle size, bulk and tapped densities. Moringa microencapsulates with soy protein isolate proved to be a better carrier of bioactive compounds of both total phenolic content and 2,2-diphenyl-1-picrylhydrazyl activity at inlet air temperature in the range of 140-180 ℃. The total phenolic content and 2,2-diphenyl-1-picrylhydrazyl activity tend to be the most stable compound. The storage stability of bioactive compounds of both Moringa microencapsulates with pea protein isolate and Moringa microencapsulates with soy protein isolate was better preserved at 4 ℃ compared to that of 25 ℃.