Giannelli Marta, Lacivita Valentina, Posati Tamara, Aluigi Annalisa, Conte Amalia, Zamboni Roberto, Del Nobile Matteo Alessandro
Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), Via Piero Gobetti 101, 40129 Bologna, Italy.
Department of Agricultural Sciences, Food and Environment, University of Foggia, Via Napoli 25, 71121 Foggia, Italy.
Foods. 2021 Nov 25;10(12):2921. doi: 10.3390/foods10122921.
In this study, a bio-based polymeric system loaded with fruit by-products was developed. It was based on silk fibroin produced by the silkworm and pomegranate peel powder, selected as active agent. The weight ratio between fibroin and pomegranate powder was 30:70. Pads also contained 20% / of glycerol vs. fibroin to induce water insolubility. Control systems, consisting of only fibroin and glycerol, were produced as reference. Both control and active systems were characterized for structural and morphological characterization (Fourier-transform infrared spectroscopy and optical microscope), antioxidant properties and antimicrobial activity against two foodborne spoilage microorganisms. Results demonstrate that under investigated conditions, an active system was obtained. The pad showed a good water stability, with weight loss of about 28% due to the release of the active agent and not to the fibroin loss. In addition, this edible system has interesting antioxidant and antimicrobial properties. In particular, the pad based on fibroin with pomegranate peel recorded an antioxidant activity of the same order of magnitude of that of vitamin C, which is one of the most well-known antioxidant compounds. As regards the antimicrobial properties, results underlined that pomegranate peel in the pad allowed maintaining microbial concentration around the same initial level (10 CFU/mL) for more than 70 h of monitoring, compared to the control system where viable cell concentration increased very rapidly up to 10 CFU/mL.
在本研究中，开发了一种负载水果副产品的生物基聚合物体系。它基于家蚕产生的丝素蛋白和作为活性剂的石榴皮粉。丝素蛋白与石榴粉的重量比为30:70。垫材中甘油与丝素蛋白的比例为20%，以诱导水不溶性。制备了仅由丝素蛋白和甘油组成的对照体系作为参考。对对照体系和活性体系进行了结构和形态表征（傅里叶变换红外光谱和光学显微镜）、抗氧化性能以及对两种食源性腐败微生物的抗菌活性研究。结果表明，在所研究的条件下，获得了一种活性体系。该垫材表现出良好的水稳定性，由于活性剂的释放导致重量损失约28%，而非丝素蛋白损失。此外，这种可食用体系具有有趣的抗氧化和抗菌性能。特别是，基于丝素蛋白和石榴皮的垫材记录的抗氧化活性与维生素C相当，维生素C是最著名的抗氧化化合物之一。关于抗菌性能，结果表明，与对照体系相比，垫材中的石榴皮在超过70小时的监测中使微生物浓度保持在大致相同的初始水平（10 CFU/mL）左右，而对照体系中活细胞浓度迅速增加至10 CFU/mL。
