Lozano-Navarro Jessica I, Díaz-Zavala Nancy P, Velasco-Santos Carlos, Martínez-Hernández Ana L, Tijerina-Ramos Beatriz I, García-Hernández Margarita, Rivera-Armenta José L, Páramo-García Ulises, Reyes-de la Torre Adriana I
Tecnológico Nacional de México-Instituto Tecnológico de Ciudad Madero, Centro de Investigación en Petroquímica, Prolongación Bahía de Aldair, Ave. de las Bahías, Parque de la Pequeña y Mediana Industria, Altamira, Tamaulipas C.P. 89600, Mexico.
Tecnológico Nacional de México-Instituto Tecnológico de Querétaro, División de Estudios de Posgrado e Investigación, Av. Tecnológico s/n esquina Gral. Mariano Escobedo, Col. Centro Histórico, Querétaro, Querétaro C.P. 76000, Mexico.
Int J Mol Sci. 2017 May 5;18(5):997. doi: 10.3390/ijms18050997.
Natural extracts possess several kinds of antioxidants (anthocyanins, betalains, thymol, carvacrol, and resveratrol) that have also demonstrated antimicrobial properties. In order to study these properties, extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and resveratrol (from grapes) were obtained. Growth inhibition tests of mesophilic aerobes, coliforms, and fungi were conducted in films prepared from the extracts in accordance with Mexican Official Norms (NOM). Optical properties such as transparency and opacity, mechanical properties, and pH were also analyzed in these materials. The films with beetroot, cranberry, and blueberry extracts demonstrated the best antimicrobial activity against various bacteria and fungi in comparison with unmodified chitosan-starch film. This study shows that the addition of antioxidants improved the antimicrobial performance of these films. It was also found that antimicrobial properties are inherent to the films. These polymers combined with the extracts effectively inhibit or reduce microorganism growth from human and environmental contact; therefore, previous sterilization could be unnecessary in comparison with traditional plastics. The presence of extracts decreased transmittance percentages at 280 and 400 nm, as well as the transparency values, while increasing their opacity values, providing better UV-VIS light barrier properties. Despite diminished glass transition temperatures (g), the values obtained are still adequate for food packaging applications.
天然提取物含有多种抗氧化剂（花青素、甜菜红素、百里香酚、香芹酚和白藜芦醇），这些抗氧化剂也具有抗菌特性。为了研究这些特性，获取了蔓越莓、蓝莓、甜菜根、石榴、牛至、火龙果的提取物以及（来自葡萄的）白藜芦醇。按照墨西哥官方标准（NOM），在由提取物制备的薄膜中对嗜温需氧菌、大肠菌群和真菌进行了生长抑制试验。还对这些材料的透明度和不透明度等光学特性、机械性能和pH值进行了分析。与未改性的壳聚糖-淀粉薄膜相比，含有甜菜根、蔓越莓和蓝莓提取物的薄膜对各种细菌和真菌表现出最佳的抗菌活性。这项研究表明，添加抗氧化剂提高了这些薄膜的抗菌性能。还发现抗菌性能是这些薄膜所固有的。这些聚合物与提取物结合可有效抑制或减少因人类和环境接触而导致的微生物生长；因此，与传统塑料相比，可能无需预先进行杀菌处理。提取物的存在降低了280和400纳米处的透光率百分比以及透明度值，同时提高了它们的不透明度值，提供了更好的紫外-可见（UV-VIS）光阻隔性能。尽管玻璃化转变温度（Tg）有所降低，但所获得的值仍足以用于食品包装应用。
