Isolation of prebiotic carbohydrates by supercritical fluid extraction. Scaling-up and economical feasibility

Lactulose production from lactose isomerization by chemo-catalysts and enzymes: Current status and future perspectives

Lactulose, a semisynthetic nondigestive disaccharide with versatile applications in the food and pharmaceutical industries, has received increasing interest due to its significant health-promoting effects. Currently, industrial lactulose production is exclusively carried out by chemical isomerization of lactose via the Lobry de Bruyn-Alberda van Ekenstein (LA) rearrangement, and much work has been directed toward improving the conversion efficiency in terms of lactulose yield and purity by using new chemo-catalysts and integrated catalytic-purification systems. Lactulose can also be produced by an enzymatic route offering a potentially greener alternative to chemo-catalysis with fewer side products. Compared to the controlled trans-galactosylation by β-galactosidase, directed isomerization of lactose with high isomerization efficiency catalyzed by the most efficient lactulose-producing enzyme, cellobiose 2-epimerase (CE), has gained much attention in recent decades. To further facilitate the industrial translation of CE-based lactulose biotransformation, numerous studies have been reported on improving biocatalytic performance through enzyme mediated molecular modification. This review summarizes recent developments in the chemical and enzymatic production of lactulose. Related catalytic mechanisms are also highlighted and described in detail. Emerging techniques that aimed at advancing lactulose production, such as the boronate affinity-based technique and molecular biological techniques, are reviewed. Finally, perspectives on challenges and opportunities in lactulose production and purification are also discussed.

Scale-up approach for supercritical fluid extraction with ethanol-water modified carbon dioxide on Phyllanthus niruri for safe enriched herbal extracts

Scaling-up supercritical fluid extraction (SFE) for the extraction of bioactive compounds from herbal plants is challenging, especially with the presence of alcohol-water as co-solvent. Hence, the main objective of this study is to validate the scale-up criteria of SFE process for Phyllanthus niruri (P. niruri), and analyse the extract safety and profitability process at the industrial scale. The study was performed by using supercritical carbon dioxide (SC-CO₂) with ethanol-water co-solvent at two operating conditions (L1: 200 bar, 60 °C and L2: 262 bar, 80 °C). The solvent-to-feed ratio (S/F) scale-up validation experiments were conducted at both operating conditions with feed mass capacity of 0.5 kg. The extraction yields and overall extraction curves obtained were almost similar to the predicted ones, with error of 5.13% and 14.2%, respectively. The safety of scale-up extract was evaluated by using a toxicity test against zebrafish embryo (FETT). The extract exhibited a low toxic effect with the LD₅₀ value of 505.71 µg/mL. The economic evaluation using a detailed profitability analysis showed that the SFE of P. niruri was an economically feasible process, as it disclosed the encouraging values of return on investment (ROI) and net present values (NPV) for all scale-up capacities.

Influence of conventional and recent extraction technologies on physicochemical properties of bioactive macromolecules from natural sources: A review

The incorporation of bioactive macromolecules from natural sources into marketable functional foods and nutraceuticals is of major significance to the agri-food sector. Interest in this area of research stems from the application of purified bioactive macromolecules in enhancing food quality and as an alternative to some pharmaceutical drugs for delivery of potential health benefits, with less associated adverse effects. To obtain bioactive macromolecules of high quality, appropriate use of extraction techniques and its influence on sensory and physicochemical properties is paramount. With the advent of technology-aided processes, there has been remarkable improvement in the extraction efficiency of these bioactive agents. An overview of the influence of these new techniques on extraction efficiency and physicochemical properties of proteins, lipids and fibers, which this detailed review provides, will prove to be a valuable resource to food industries aiming to maximize production of bioactive macromolecules from natural sources as well as the scientific community.

Biofuels from microalgae: lipid extraction and methane production from the residual biomass in a biorefinery approach

Renewable fuels and energy are of major concern worldwide and new raw materials and processes for its generation are being investigated. Among these raw materials, algae are a promising source of lipids and energy. Thus, in this work four different algae have been used for lipid extraction and biogas generation. Lipids were obtained by supercritical CO2 extraction (SCCO2), while anaerobic digestion of the lipid-exhausted algae biomass was used for biogas production. The extracted oil composition was analyzed (saturated, monounsaturated and polyunsaturated fatty acids) and quantified. The highest lipid yields were obtained from Tetraselmis sp. (11%) and Scenedesmus almeriensis (10%), while the highest methane production from the lipid-exhausted algae biomass corresponded to Tetraselmis sp. (236mLCH4/gVSadded).