Ultrasound-Assisted Extraction of Anthocyanins from Haskap (Lonicera caerulea L.) Berries Using a Deep Eutectic Solvent (DES) DES Extraction of Anthocyanins from Haskap Berries.

RESEARCH BACKGROUND: Haskap berries are one of the richest natural sources of anthocyanins and their extracts can be used for nutraceuticals and functional food ingredients. Deep eutectic solvents (DES) comprising food-grade or generally recognized as safe (GRAS) components show promise as natural solvents, but have not been applied to haskap berries. Thus, the aim of this study is to investigate the extraction of anthocyanins from haskap berries using a DES consisting of citric acid and d-(+)-maltose. EXPERIMENTAL APPROACH: The experimental approach used ultrasound-assisted extraction with a DES consisting of citric acid and d-(+)-maltose as the solvent to achieve a sustainable green extraction process. Response surface methodology (RSM) with a Box-Behnken experimental design was used to study the effect of varying the extraction temperature, time of extraction, V(solvent)/m(sample) ratio (mL/g) and the water volume fraction (%) in the DES on the total anthocyanin content (TAC) in the haskap berry extracts. RESULTS AND CONCLUSIONS: Under the optimal extraction conditions (75 °C, 10 min, 50.4 mL/g and 90% water) a predicted TAC extraction on dry mass basis yielded 21.2 mg/g, with experimental error of 7.2%. The TAC yield and anthocyanin profiles were similar to those obtained with conventional organic solvents. NOVELTY AND SCIENTIFIC CONTRIBUTION: This is the first study investigating the use of a food-grade DES comprising GRAS components for the extraction of anthocyanins from haskap berries. These results indicate that the studied DES (citric acid and d-(+)-maltose) is a suitable alternative solvent for extracting anthocyanins for food-grade applications.

Sustainable approach for lycopene extraction from tomato processing by-product using hydrophobic eutectic solvents.

Lycopene, a non-polar antioxidant compound with important effects on human health and wide commercial applications, was extracted from tomato processing wastes using innovative hydrophobic eutectic mixtures (HEMs) replacing traditional organic solvents. HEMs were prepared using DL-menthol as hydrogen-bond acceptor (HBA) and lactic acid as hydrogen-bond donor (HBD), and the ultrasound-assisted extraction (UAE) was optimized using a Box-Behnken design to evaluate extraction conditions: extraction temperature (°C), molar ratio of eutectic mixture (moles HBA: mol HBD), solvent to sample ratio (volume to mass, mL/g), and extraction time (min), with lycopene extraction yield (µg/g d.w.) as the response variable. Optimization of parameters was performed using response surface methodology, and the optimized extraction conditions were determined to be 70 °C, 8:1 mol HBA/mol HBD, 120 mL/g solvent: sample, and 10 min. The experimental optimal yield was 1446.6 µg/g, in agreement with the predicted optimal yield, indicating the validity of the model. This new technique for lycopene extraction, using a HEM as extraction solvent in replacement of hazardous organic solvents, and tomato pomace as source material, represents a viable and more sustainable approach for obtaining a high value-added bioactive compound, and can contribute towards the development of greener extraction processes.

Development and evaluation of floating alginate microspheres for oral delivery of anthocyanins - A preliminary investigation.

The goal of this study was to develop floating microspheres that could be used as gastroretentive systems for the delivery of anthocyanins (ACNs). These compounds are absorbed in the stomach and small intestine, and insufficient residence time in these organs could result in limited absorption and contribute to degradation. The microparticles containing freeze-dried haskap berry extract (321.96 ± 8.35 mg cyanidin 3-glucoside equivalents per g) were prepared by ionotropic gelation of alginate (9%, w/w) with calcium ions (CaCl2 at 2%, w/v) in the gelation bath, with calcium carbonate as the gas-generating compound (added at different ratios in the alginate/extract mixture). The effect of acetic acid concentration (2 and 10%, v/v) in the gelation medium was investigated. Increasing the carbonate : alginate weigh ratio from 0 to 3:4 resulted in different degrees of floatability, larger particles, higher encapsulation efficiency, and lower amount of ACN released. The power law equation fitted the experimental data well, indicating that release occurred mainly by diffusion. This is the first time floating microspheres are proposed as gastroretentive platforms for the delivery of ACNs.

Recycling of lipid-extracted hydrolysate as nitrogen supplementation for production of thraustochytrid biomass.

Efficient resource usage is important for cost-effective microalgae production, where the incorporation of waste streams and recycled water into the process has great potential. This study builds upon emerging research on nutrient recycling in thraustochytrid production, where waste streams are recovered after lipid extraction and recycled into future cultures. This research investigates the nitrogen flux of recycled hydrolysate derived from enzymatic lipid extraction of thraustochytrid biomass. Results indicated the proteinaceous content of the recycled hydrolysate can offset the need to supply fresh nitrogen in a secondary culture, without detrimental impact upon the produced biomass. The treatment employing the recycled hydrolysate with no nitrogen addition accumulated 14.86 g L(-1) of biomass in 141 h with 43.3 % (w/w) lipid content compared to the control which had 9.26 g L(-1) and 46.9 % (w/w), respectively. This improved nutrient efficiency and wastewater recovery represents considerable potential for enhanced resource efficiency of commercial thraustochytrid production.

Sequential recycling of enzymatic lipid-extracted hydrolysate in fermentations with a thraustochytrid.

This study extends the findings of prior studies proposing and validating nutrient recycling for the heterotrophic microalgae, Thraustochytrium sp. (T18), grown in optimized fed-batch conditions. Sequential nutrient recycling of enzymatically-derived hydrolysate in fermentors succeeded at growing the tested thraustochytrid strain, with little evidence of inhibition or detrimental effects upon culture health. The average maximum biomass obtained in the recycled hydrolysate was 63.68±1.46gL(-1) in 90h the first recycle followed by 65.27±1.15gL(-1) in 90h in the subsequent recycle of the same material. These compared to 58.59gL(-1) and 64.92gL(-1) observed in fresh media in the same time. Lipid production was slightly impaired, however, with a maximum total fatty acid content of 62.2±0.30% in the recycled hydrolysate compared to 69.4% in fresh control media.

Nutrient recycling of lipid-extracted waste in the production of an oleaginous thraustochytrid.

Improving the economics of microalgae production for the recovery of microbial oil requires a comprehensive exploration of the measures needed to improve productivity as well as to reduce the overall processing costs. One avenue for cost reduction involves recycling the effluent waste water remaining after lipid extraction. This study investigates the feasibility of recycling those wastes for growing thraustochytrid biomass, a heterotrophic microalgae, where wastes were generated from the enzymatic extraction of the lipids from the cell biomass. It was demonstrated that secondary cultures of the tested thraustochytrid grown in the recycled wastes performed favorably in terms of cell and oil production (20.48 g cells L(-1) and 40.9 % (w/w) lipid) compared to the control (13.63 g cells L(-1) and 56.8 % (w/w) lipid). Further, the significant uptake of solubilized cell material (in the form of amino acids) demonstrated that the recycled waste has the potential for offsetting the need for fresh medium components. These results indicate that the implementation of a nutrient recycling strategy for industrial microalgae production could be possible, with significant added benefits such as conserving water resources, improving production efficiency, and decreasing material inputs.

Nutrient and media recycling in heterotrophic microalgae cultures.

In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

Use of an oxygen-releasing compound to aerate eutrophic reservoir water.

This study examined the use of an Oxygen Release Compound (ORC) as a slow release chemical aeration agent within eutrophic surface water systems. Bench and pilot-scale experiments involving ORC treatment of eutrophic reservoir water were conducted to determine operational properties of ORC and examine its performance as an aeration agent within a surface water environment. The bench-scale study involved the application of 10, 25 and 50 g ORC doses to 1 L Erlenmeyer flasks containing various water and sediment samples. The pilot-scale study involved a scaled up simulation of full-scale reservoir systems using large fiberglass tanks, where water quality parameters in an ORC-treated tank were compared to an untreated tank over a 4 month period. The results of these experiments indicate that the application of ORC can result in substantial increases in dissolved oxygen and pH when applied to deoxygenated water systems. Within the pilot scale study, a 300 g/m2 dose of ORC at the sediment water interface prevented the onset of anoxic conditions over a 4 month growing season period, releasing approximately 20% of its mass as oxygen within this time frame.