Production and characterization of Gluconacetobacter xylinus bacterial cellulose using cashew apple juice and soybean molasses.

Bacterial cellulose (BC) has been largely used in biomedical and technological fields. The use of agro-industrial byproducts as alternative source of carbon and nitrogen in culture media reduces the BC cost production, adds value to the byproducts and minimizes the environmental impact. In this study, the use of cashew apple juice and soybean molasses were evaluated to produce BC by Gluconacetobacter xylinus in comparison to the usual Hestrin and Schramm medium (HS). BC produced in static cultivation was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The BC production (4.50 g L-1) obtained from the medium using cashew apple juice as carbon source (20 g L-1) with soybean molasses as nitrogen source (10 g L-1) was superior than HS medium (4.03 g L-1). Morphological analysis showed that bacterial celluloses produced with agro-industrial byproducts combined were similar to those found for the pellicle obtained from HS medium.

Use of grape pomace for the production of hydrolytic enzymes by solid-state fermentation and recovery of its bioactive compounds.

A cocktail of biomass hydrolytic enzymes was produced by solid-state fermentation (SSF) by the mutant strain Aspergillus niger 3T5B8, using as substrate a mixture of grape pomace and wheat bran, and compared to the production when wheat bran was used as the sole substrate. The two enzymatic cocktails were subsequently used for the extraction of bioactive compounds from grape pomace and the relationship between the activities of the cocktail and the release of phenolic compounds was evaluated. Although the wheat bran SSF process was more effective for enzyme production, the enzymatic cocktail produced by the grape pomace - wheat bran mixture was more effective for the extraction of compounds with higher proanthocyanidins content and higher antioxidant potential (p < 0.05). A significant correlation between the bioactive compounds and enzyme activity was observed.

Influence of processing conditions on bioactive compound extraction from Vitis vinifera L. var. Alicante Bouschet grape skin.

The aim of this study was to evaluate the effects of process conditions on the solid-liquid extraction of bioactive compounds from the Alicante Bouschet grape skin from the semi-arid region of Brazil. The influence of temperature (23-57 °C), ethanol concentration (16-84%) and citric acid concentration (0-4%) on the total phenolic content, monomeric anthocyanin content and on the antioxidant capacity of the extracts measured by oxygen radical absorbance capacity and cation radical scavenging activity (ABTS·+) methods was investigated. Ethanol concentration and temperature had a significant influence on total phenolic compounds extraction and antioxidant capacity while monomeric anthocyanins extraction was only affected by ethanol concentration. The conditions selected as the most adequate for the extraction were: temperature of 40 °C, 50% v/v ethanol and 2% m/v citric acid.

Effect of enzymatic treatment on the rheological behavior and vitamin C content of Spondias tuberosa (umbu) pulp.

Umbu is a native fruit of the semi-arid Northeastern region of Brazil, which presents an exotic and differentiated flavor. Containing vitamin C and presenting a high potential of consumption, no appropriated technology has been developed to process this fruit and expand its commercialization to other markets. The enzymatic treatment of fruit pulps leads to viscosity reduction, which makes possible an efficient processing for obtaining high quality umbu juices. In order to contribute to the valorization of this underexploited culture, two commercial pectinolytic enzymes, Pectinex Ultra SP-L® and Rapidase TF®, were used to promote viscosity reduction of umbu pulp. The effect of reaction temperature (35, 45 and 55 °C) and enzyme concentration (100, 200 and 300 ppm) on the rheological properties of the fruit pulp was evaluated. In relation to the viscosity of the original pulp (84.8 mPa s at 100 s-1 shear rate), a significant, four times lower, viscosity reduction of 18.9 mPa s was observed. Under optimum process condition (35 °C and Rapidase at 100 ppm concentration), the lowest viscosity was achieved after 40 min of reaction. Under these reaction conditions, no significant change was found in the vitamin C content, indicating the preservation of functional and nutritional properties of umbu pulp.