Silk Fibroin and Pomegranate By-Products to Develop Sustainable Active Pad for Food Packaging Applications

Abstract

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 Bombyx mori and pomegranate peel powder, selected as active agent. The weight ratio between fibroin and pomegranate powder was 30:70. Pads also contained 20% w/w 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 (104 CFU/mL) for more than 70 h of monitoring, compared to the control system where viable cell concentration increased very rapidly up to 108 CFU/mL.

Eco-Sustainable Silk Fibroin/Pomegranate Peel Extract Film as an Innovative Green Material for Skin Repair

“…Pomegranate organic fruits (WonderFul variety) were kindly provided by the Horticultural Association (A.P.O.130, Foggia, Italy), and pomegranate peel powder was prepared by the University of Foggia (Department of Agricultural Sciences, Food and Environment), according to literature data [ 31 ].…”

“…Several natural antioxidants, such as quercetin, grape seed extract, vitamin C, tannins, oleuropein and rutin, have been incorporated or absorbed into SF in order to obtain bio-based materials for biomedical applications [ 28 , 29 , 30 ]. Recently, we developed an active pad based on pomegranate peel powder and reduced the amount of SF, used as glue, for food packaging applications [ 31 ]. However, the use of SF in skin repair with a bioactive antioxidant product derived from waste material such as pomegranate peel had before now not been studied.…”

Pomegranate Peel Powder: In Vitro Efficacy and Application to Contaminated Liquid Foods

“…Chitosan-based coatings with incorporated pomegranate peel extracts have been applied to rainbow trout [ 22 ] and Pacific white shrimp [ 23 ]. Giannelli et al [ 24 ] recently developed an active pad based on silk fibroin and pomegranate peel powder, with the potential to be adopted for food packaging. It is abundantly recognized that for regulatory reasons, delivery systems of active compounds are advantageous.…”

“…In addition, biopolymers from biowastes offer great opportunities to decrease the devastating overuse of plastic-based packaging [ 18 ]. Starting from results of Giannelli et al [ 24 ], in the current study, the active pad made up of silk fibroin and pomegranate peel powder was applied to contaminated fresh liquid food. The active pad was developed by considering that silk fibroin acted as a reservoir of antimicrobial phenolics contained in the pomegranate peel, which reached the food mainly through diffusion.…”

EPR-based study to monitor Free Radicals in Treated Silk Fibroin with Anthocyanins

“…Achieved higher results in aqueous extract (15). Antioxidant and antimicrobial active pads have been developed from the interaction of pomegranate peel powder and SF solution (16). Ethyl acetate extract of smoke tree leaves has been used in both biomedical research and the development of anticancer therapeutic strategies and has yielded high results (17).…”