Valorization of Artichoke Industrial By-Products Using Green Extraction Technologies: Formulation of Hydrogels in Combination with Paulownia Extracts.

The integral valorization of artichoke bracts generated during industrial canning of artichoke was assessed. The extraction of bioactive compounds was addressed with pressurized hot water under subcritical conditions. The performance of this stage on the extraction of phenolics with antioxidant properties and the saccharidic fraction using conventional and microwave heating was compared. The microwave assisted process was more efficient than the conventional one regarding extraction yields of total solubles, and glucose and fructose oligomers and phenolics, because lower operational temperatures and shorter times were needed. Degradation of fructose oligomers was observed at temperatures higher than 160 °C, whereas the maximal phenolic content occurred at 220 °C. Both the extracts and the residual solids, obtained at conditions leading to maximum phenolics yields, were evaluated for the production of starch-based hydrogels, supplemented with Paulownia leaves' aqueous extracts.

The enhancement of antioxidant compounds extracted from Thymus vulgaris using enzymes and the effect of extracting solvent.

We evaluate the total phenolic compounds (TPC) content and the antioxidant activity (AA) of extracts obtained from ground fresh thyme (FT) and depleted thyme (DT), a by-product of the process of essential oil extraction. In addition, enzymatic treatments were evaluated to improve the extraction yields of polyphenolic compounds from thyme. Extractions were performed using several solvents as methanol, ethanol, and water. Enzymes were applied prior to extraction or during the extraction process. The best results were obtained using a mixture of methanol and water, resulting in 2790 and 220 mg Gallic acid equivalent (GAE)/L of TPC for FT and DT, respectively. A similar result was observed for AA. With regard to enzymatic treatment, application of Grindamyl CA 150 enzyme as a pre-treatment resulted in the production of an extract from DT with 614 mg TE (trolox equivalent)/L of AA, 70% more than the control, and an AA of 621 mg TE/L (74% more than the control sample) was obtained using Grindamyl CA 150 during the extraction process. These results suggest that enzymatic treatment is an interesting alternative for producing antioxidant extracts from DT.

Phenolic antioxidants extraction from raspberry wastes assisted by-enzymes

The effect of enzymatic hydrolysis on phenolic antioxidant extraction was studied in raspberry solid wastes. This by-product possesses high content of crude fiber (60 percent) and low values of protein, oil and ash. Raspberry fiber composition suggests that biocatalysts with cellulase, hemicellulase and pectinase activities would be useful for carrying out an enzymatically assisted antioxidant extraction. Hydro-alcoholic extraction was done using different commercial enzymes. Total phenol content and antioxidant activity of enzyme-hydrolyzed residue extracts were measured and compared with those obtained without enzyme application. All biocatalysts evaluated increased soluble solids in comparison to the non-enzymatic control. Among them, Grindamyl and Maxoliva offered the best recovery of polyphenols. Enzymatic assisted extraction with an hydro-ethanolic mixture (75:25, v/v) during 18 hrs at 50°C increased phenolic content up to 35 percent and antioxidant capacity around 50 percent, 15 percent and 30 percent according to 2,2-diphenyl-1-picrylhydrazyl = 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl) (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) methods, respectively. Use of a higher enzyme concentration significantly improved extraction of phenolic antioxidants.

Inmovilización de lactasa microbiana / Immobilization of microbial lactase

La lactasa tiene un gran potencial de aplicación en la industria láctea como modificador de propiedades funcionales y nutricionales de leche y derivados y como agente de recuperación del suero de quesería. Este último aspecto se ha abordado a fin de producir y utilizar catalizadores enzimáticos para la hidrólisis continua de permeado de suero. La selección de enzima y soportes y la optimización de la metodología de inmovilización ya han sido reportadas. Los resultados obtenidos con lactasa inmovilizada en quitina han motivado el intento de escalar los procedimientos a nivel productivo, Un primer objetivo ha sido el desarrollo de un sistema de inmovilizacion en el reactor (in situ) adecuado a la operación en planta. Se presentan los resultados de inmovilización in situ en sistemas por lote cerrado y con recirculacióon. Los resultados del protocolo de inmovilización original optimizado son reproductibles, si bien se observan gradientes de actividad enzimática a lo largo del reactor, las que no se logra eliminar por recirculación de reactantes. Se presenta los resultados de operación de reactores continuos de lecho fijo con lactasa inmovilizada in situ, operando a distintos flujos y concentraciones de lactosa. Los grados de conversion y productividad obtenidos se comparan con un modelo simple, desarrollado en base a la expresión cinética correspondiente y un regimen de flujo piston. La desviación es significativa a flujos de operación altos, lo que se atribuye a retromezclamiento y canalización a través del lecho catalítico, obteniéndose un mejor ajuste a flujos bajos y altas concentraciones de sustrato de alimentación. La productividad fue máxima a 120 g/1 de lactosa y 40 ml/h e igual a 58 g de glucosa/1.h. La estabilidad del catalizador fue evaluada en el reactor a pH 4,0 y 40 C con permeado de suero, calculándose un tiempo de vida media operacional de 120 dias