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© 2014 Institute of Food Technologists®. Four chitosan samples were prepared from shrimp shells without deproteination and decoloration steps, by a deacetylation process at 2 reaction times (2 and 4 h) and with/without using a reducing agent (R.A.). Variations in the physicochemical properties of the final products were analyzed. Viscosity average molecular weight (Mw) determinations demonstrated the protective action of the R.A. on the molecular oxidative degradation. Oppositely, an increase on the reaction time produced samples with low Mw. Deacetylation degrees (DDs) were chemically evaluated by the nitrogen content and by spectroscopic techniques as infrared and nuclear magnetic resonance. The existing differences in crystallinity were studied by X-ray diffraction. Differential scanning calorimetry and thermogravimetry were used to demonstrate the dehydration and thermal degradation processes of the different chitosans. A novel method from calorimetric profiles is presenting for DD determinations of chitosan, which achieved highly satisfactory results (linear fit and Pearson's correlation coefficient) and is proposed to be generally extended to complex curves application. Practical Application: A new thermal parameter from differential scanning calorimetry is proposed for deacetylation degree analysis that could be of advantageous usefulness against traditional methods in complex reactions applications. A complete study of Pearson's correlation coefficient performed over all the investigated physicochemical and thermal parameters clearly supports the use of the new thermal parameter. After validation, it could be normalized and automatized to be implanted as a short and easy quality control, analytical method with potential applications in the food and related industries.

Active biodegradable bilayer films based on agar and sodium alginate were developed by the incorporation of cinnamon essential oil in the upper layer. The release of both cinnamaldehyde and eugenol from the agar and alginate bilayer films into water at 4 °C and 20 °C did not increase significantly from 9 h onwards, and consequently increasing values of antioxidant activity measured by ferric reducing ability and radical scavenging capacity were observed until 9 h in both cases. Agar bilayer films showed an antimicrobial activity approximately 1.4-fold higher than the alginate bilayer films, although both of them were effective against all the microorganisms tested in this study, especially against Photobacterium phosphoreum. Both agar and alginate bilayer films allowed to reduce significantly the microbial growth, including the pathogenic bacteria Listeria monocytogenes, in peeled shrimps during the chilled storage without a negative impact on the organoleptic properties. © 2014 Elsevier Ltd., This research was financed by the Spanish Ministry of Science and Innovation under the project AGL2011-27607

7 páginas, 3 figuras, 2 tablas, A concentration-response bioassay against the Mediterranean fruit fly, Ceratitits capitata, was performed to evaluate the insecticidal activity of biodegradable films containing clove (Eugenia caryophyllata, Myrtaceae) or citronella (Cymbopogon nardus, Poaceae) oils. We recorded the time of knock down flies after the exposure to soy protein-lignin films incorporated with 3% food grade clove or citronella essential oils, or control films without bioactive. The vapors of clove released from the film containing 3% essential oil were efficient to trigger the tumbling of the flies (40% after 4 h exposition) and after 20 h 90% of the flies died. However, films containing citronella essential oil had poor insecticidal activity. Citronella oil have a much higher insecticidal activity in a pure form, but probably one or both of their main bioactive compounds (citronellal and geraniol) were poorly released from the films. In this work, for the first time, a novel packaging system controlling the release of essential oil of clove with good insecticidal activity against Ceratitits capitata was achieved, that can be used to improve quality of fruit and for food products., Thank for the financial support to SENESCYT Scholarship of the Ecuadorian government of M. Arancibia and CYTED (action 309AC0382) Agrobioenvase

Presentado en el Congreso Effost Annual Meeting ,celebrado en España el 9 de noviembre de 2011., Technical University of Berlin. Alemania