Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Burjassot, Spain.
Int J Food Microbiol. 2010 Aug 15;142(1-2):222-8. doi: 10.1016/j.ijfoodmicro.2010.07.001. Epub 2010 Jul 23.
The antimicrobial activity of newly developed cellulose-silver nanoparticle hybrid materials was investigated during storage of minimally processed "Piel de Sapo" melon. Silver nanoparticles were produced after in-situ reduction by physical methods of 1% silver nitrate adsorbed on cellulose fibres; they accounted between 5 and 35 nm diameter, and were not aggregated. Fresh-cut melon pieces were stored for 10 days at 4 degrees C under natural modified atmosphere packaging, in presence or absence of silver loaded absorbent pads. The evolution of headspace gas composition, quality parameters, and the antimicrobial activity against spoilage-related microorganisms were investigated. The cellulose-silver nanoparticle hybrid materials released silver ions after melon juice impregnated the pad. The released silver ions were particularly useful to control the population of spoilage-related microorganisms in cellulose based absorbent pads in contact with vegetable matrices, showing a low chelating effect against silver ions; the lag phases of the microorganisms were considerably incremented and microbial loads in the pads remained in average approx. 3 log(10) CFU/g below the control during the investigated storage period. Furthermore, the presence of silver loaded absorbent pads retarded the senescence of the melon cuts, presenting remarkably lower yeast counts, lower degrees Brix values, and a juicier appearance after 10 days of storage.
新开发的纤维素-银纳米粒子杂化材料的抗菌活性在“Piel de Sapo”蜜瓜的微加工贮藏过程中进行了研究。通过物理方法原位还原吸附在纤维素纤维上的 1%硝酸银，生成了银纳米粒子，其直径在 5 至 35nm 之间，且未发生聚集。新鲜切割的蜜瓜块在 4°C 下用天然改良气氛包装储存 10 天，存在或不存在负载银的吸收垫。研究了顶空气体组成、质量参数的演变以及对与变质相关的微生物的抗菌活性。当蜜瓜汁渗透到垫子里时，纤维素-银纳米粒子杂化材料释放出银离子。释放出的银离子特别有助于控制与纤维素基吸收垫中与蔬菜基质接触的变质相关微生物的种群，对银离子的螯合作用较低；在研究的贮藏期内，微生物的滞后期大大增加，垫子里的微生物负载平均约为 3log(10)CFU/g，低于对照。此外，负载银的吸收垫的存在延缓了蜜瓜的衰老，在储存 10 天后，酵母计数显著降低，白利糖度值降低，外观更鲜嫩多汁。
