Colorimetric Indicator Based on Gold Nanoparticles and Sodium Alginate for Monitoring Fish Spoilage.

In this work, a colorimetric indicator based on gold nanoparticles (AuNP) and a biodegradable and eco-friendly polymer (sodium alginate, Alg.), was developed for the real-time detection of fish spoilage products. The AuNPs and the colorimetric indicator were characterized using UV-VIS, FTIR spectroscopies, TGA, DSC, XRD, TEM, and colorimetry.

Protection of polyphenols in blueberry juice by vacuum-assisted block freeze concentration.

Block freeze concentration allows produces high-quality cryoconcentrates with important protection of valuable components from fresh fruit juices. The aim of this study was to investigate the use of vacuum-assisted block freeze concentration under different experimental conditions to protect polyphenols in the elaboration of concentrated blueberry juice. Fresh blueberry juice was radial or unidirectional frozen at -20 and -80 °C for 12 h and vacuum process was performed at 80 kPa during 120 min.