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Ultrasound-assisted extraction (UAE) of antioxidant polyphenols from chicory grounds was studied in order to propose a suitable valorization of this food industry by-product. The main parameters influencing the extraction process were identified. A new mathematical model for multi-criteria optimization of UAE was proposed. This kinetic model permitted the following and the prediction of the yield of extracted polyphenols, the antioxidant activity of the obtained extracts and the energy consumption during the extraction process in wide ranges of temperature (20-60°C), ethanol content in the solvent (0-60% (vol.) in ethanol-water mixtures) and ultrasound power (0-100W). After experimental validation of the model, several simulations at different technological restrictions were performed to illustrate the potentiality of the model to find the optimal conditions for obtaining a given yield within minimal process duration or with minimal energy consumption. The advantage of ultrasound assistance was clearly demonstrated both for the reduction of extraction duration and for the reduction of energy consumption.

Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The main step in the extraction protocol used in the alginate industry is that of alkaline extraction. A batch process is used for this step, which is time-, water-, and reactant-consuming. The possibility of extracting by reactive extrusion was investigated. The reactive extrusion process appeared to be more efficient than the batch process for the alkaline extraction of alginates from Laminaria digitata in several key ways: Time demand is reduced from about an hour to only few minutes, water and reactant requirements are divided by more than a factor 2, extraction yield is 15% higher (relative enhancement), and the rheological properties of the product were all enhanced. Hence, reactive extrusion could be an interesting alternative process for the alginate industry to produce high rheological properties alginates.

Several antibacterial peptides can be obtained by enzymatic hydrolysis of the α chain of bovine hemoglobin. The kinetics of α1-32 peptide hydrolysis by pepsin was studied at several temperatures (15, 23 and 37 °C). Intermediate and final peptides were identified, and their antibacterial activity was assessed against four bacterial species. Evolution of generated peptides concentration enabled to propose a reaction pathway describing the parallel and consecutive reactions taking place during the hydrolysis. A mathematical model, based on the proposed mechanism, was developed to describe the kinetics of generated peptides during α1-32 hydrolysis. The constants of the main reactions were identified based on the experimental data, and their dependence on temperature was established using Arrhenius-type equations. Validation of the proposed model was performed by predicting kinetics of α1-32 peptide hydrolysis at 30 °C (all other experimental conditions being unchanged) with a good accuracy. This mathematical model could allow defining the optimal conditions for the production of various intermediate peptides with antibacterial activity from peptic hydrolysis of α1-32 peptide.

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