Microencapsulation of Phenolic Extracts from Cocoa Shells to Enrich Chocolate Bars.

Cocoa bean shells were subjected to green extraction technologies, based on the absence of toxic organic solvents, to recover polyphenols; the extract was then encapsulated using a spray dryer and maltodextrin as coating agent. The best conditions observed in the spray drying tests (core-to-coating ratio 1:5; inlet temperature 150 °C; flow rate 6 ml min-1) were applied to produce the microcapsules used to enrich the same cocoa mass as the shells and processed for the preparation of the chocolate bars. Sensory analysis showed no significant differences between enriched chocolate bar and the unenriched reference one, except for the appearance. Both samples were then subjected to accelerated storage tests, at the end of which the polyphenols in the control chocolate bar (0.85 g 100 g-1) were reduced by about 50% (0.42 g 100 g-1), while in the enriched chocolate (1.17 g 100 g-1) by only 22% (0.97 g 100 g-1). The proposed process significantly enriched the chocolate bars with phenolic antioxidants recovered from cocoa waste without increasing the sensations of bitterness and astringency.

Kinetics of carotenoids degradation and furosine formation in dried apricots (Prunus armeniaca L.).

The kinetics of carotenoid and color degradation, as well as furosine formation, were investigated in apricot fruits during convective heating at 50, 60 and 70°C. Degradation of carotenoids and color, expressed as total color difference (TCD), followed a first and zero order kinetic, respectively. The activation energy (Ea) for carotenoids degradation ranged from 73.7kJ/mol for 13-cis-ß-carotene to 120.7kJ/mol for lutein, being about 91kJ/mol for all-trans-ß-carotene. Violaxanthin and anteraxanthin were the most susceptible to thermal treatment. The furosine evolution was fitted at zero order kinetic model. The Ea for furosine formation was found to be 83.3kJ/mol and the Q10 (temperature coefficient) varied from 1.59 to 4.14 at the temperature ranges 50-60°C and 60-70°C, respectively.

Rapid determination of collagen in meat-based foods by microwave hydrolysis of proteins and HPAEC-PAD analysis of 4-hydroxyproline.

A rapid microwave procedure for protein hydrolysis coupled with High Performance Anion Exchange Chromatography and Pulsed Amperometric Detection (HPAEC-PAD) was developed to quantify the amino acid 4-hydroxyproline in meat and meat-based products. This innovative approach was successfully applied to determine collagen content (4-hydroxyproline×8) as the index quality of meat material employed in the preparation of typical meat sausages ("Mortadella di Bologna PGI" and "Salamini italiani alla cacciatora PDO") and fresh filled pastas. Microwave hydrolysis showed a precision and accuracy similar to traditional hydrolysis (RSD% from 0.0 to 6.4; relative error 1.4-10.0%) with a reduction in the hydrolysis time from 24h to 20min. HPAEC-PAD allowed detection of 4-hydroxyproline without pre or post-column derivatization and the use of non-toxic eluents.

Development of a biosensor for monitoring of glycerol during alcoholic fermentation.

A biosensor for the measurement of glycerol in FIA was constructed using covalently immobilized glycerokinase and glycerol-3-phosphate oxidase in conjunction with a Pt based hydrogen peroxide probe. Different immobilization strategies have been studied including random and asymmetric immobilization onto a polymeric support and immobilization onto two different membranes. The latter resulted in the best configuration for batch measurement. The most effective configuration for measurement in FIA was the immobilization of glycerokinase in a glass beads reactor coupled with glycerol-3-phosphate oxidase on a preactivated Immobilon AV membrane kept at the electrode surface. Using a 250-microliter injection loop, 3 mmol ATP(Mg+2) in 0.1 M borate buffer pH 8.5 and a flow rate of 0.5 ml/min, a linear response in the 2 x 10(-6)/10(-3) mol/l range and a detection limit of 5 x 10(-7) mol/l were obtained for glycerol. Lifetime of the glycerol-3-phosphate membrane was extended up to 1 month by storage in the working buffer containing 1% DEAE-dextran and 5% lactitol. More than 350 samples can be assayed with this system. The biosensor was used to monitor off-line glycerol production during alcoholic fermentations carried out at different pHs and temperatures.