Browsing by Author "Abarca, Romina L."

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    Biodegradable gelatin-based films with nisin and EDTA that inhibit Escherichia coli
    (2022) Abarca, Romina L.; Medina, Javiera; Alvarado, Nancy; Ortiz, Pablo A.; Carrillo Lopez, Bernardo
    In this study, we developed gelatin-based films for active packaging with the ability to inhibit E. coli. We created these novel biodegradable gelatin-based films with a nisin-EDTA mix. FT-IR, TGA, and SEM analysis showed that nisin interacted with the gelatin by modifying its thermal stability and morphology. The use of nisin (2,500 IU/mL) with concentrations of Na-EDTA (1.052 M stock solution) distributed in the polymer matrix generated a significant decrease in the growth of E. coli when compared to the control. In freshly made films (t(0)), the growth of E. coli ATCC 25922 was reduced by approximately 3 logarithmic cycles. Two weeks after the films were made, a reduction in antimicrobial activity was observed in approximately 1, 1 and 3 logarithmic cycles of the films with 5%, 10% and 20% of the compound (nisin/Na-EDTA) distributed in the polymer matrix, respectively. This evidences an antimicrobial effect over time. Also, biodegradation tests showed that the films were completely degraded after 10 days. With all these results, an active and biodegradable packaging was successfully obtained to be potentially applied in perishable foods. These biodegradable, gelatin-based films are a versatile active packaging option. Further research on the barrier properties of these films is needed.
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    Development and Characterization of Films with Propolis to Inhibit Mold Contamination in the Dairy Industry
    (2023) Abarca, Romina L.; Vargas, Francisco; Medina, Javiera; Paredes, Juan Carlos; Lopez, Bernardo Carrillo; Ortiz, Pablo A. A.; Vargas-Bello-Perez, Einar
    Due to the number of polyphenols with multiple biological activities, propolis has high potential to be used as an active agent in food protective films. Therefore, this study aimed to develop and characterize a sodium alginate film with ethanolic extract of propolis (EEP) for its potential use as protective active packaging against filamentous fungi in ripened cheese. Three different concentrations of EEP were analyzed: 0, 5 and 10% w/v. The films obtained were characterized, assessing thermal and physicochemical properties, as well as the concentration of polyphenols in the EEP and antifungal activity of the active films. The incorporation of EEP in the films generated thermal stability with respect to the loss of mass. Total color values (Delta E) of the films were affected by the incorporation of the different concentrations of EEP, showing a decrease in luminosity (L*) of the films, while the chromatic parameters a* and b* increased in direct proportion to the EEP concentration. Antifungal activity was observed with a fungistatic mode of action, stopping the growth of the fungus in cheeses without development of filamentous molds, thus increasing the shelf life of the ripened cheese under the analytical conditions, over 30 days at room temperature. Overall, EEP can be used to prevent growth and proliferation of spoilage microorganisms in cheese.
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    SYNTHESIS, CHARACTERIZATION AND FILM PREPARATION OF NEW CO-POLYIMIDE BASED ON NEW 3,5-DIAMINO-N-(PYRIDIN-4-YLMETHYL)BENZAMIDE, ODA AND 6FDA
    (2018) Tundidor-Camba, Alain; Saldias, Cesar; Tagle, Luis H.; Terraza, Claudio A.; Coll, Deysma; Perez, German; Aguilar-Vega, Manuel; Abarca, Romina L.; Ortiz, Pablo A.
    This work describes mainly the synthesis and characterization of new co-polyimides obtained from the polycondensation of the dianhydride 4,4'-(hexafluoroisopropylidene)diphtlialic anhydride (6FDA), 4,4'-oxydianiline (ODA) and the new diamine 3,5-diamino-N-(pyridin-4-ylmethyl)benzamide (PyDA). It describes as the different compositions of ODA and PyDA present in the polymers. produce variation on thermal and mechanical properties, which are important characteristics for the development of future nanocomposites derived from these polymers. Both PyDA monomer and polymers were characterized using FT-IR and NMR (H-1, C-13, F-19, dept 135 degrees, COSY, HMBC, HMQC) spectroscopy. The inherent viscosity of polymers is between 0.3 to 1.49 dL/g, they are soluble in aprotic polar solvents, such as: DMSO, DMF and DMA. In addition, all co-polymers showed thermal decomposition temperature and glass transition temperatures above 483 degrees C and 289 degrees C, respectively. Mechanical tests under tension of co-polymer films showed Young's modulus between 2.1-3.9 GPa and tensile strength between 35.5 and 120.0 MPa. On the other hand, an increase in crystallinity and hydrophilicity is observed when increasing the amount of pyridinyl groups.