Centre for Rapid and Sustainable Product Development

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Poultry Shelf-Life Enhancing Potential of Nanofibers and Nanoparticles Containing Porphyra dioica Extracts

Publication . Reboleira, J.; Adão, P.; Guerreiro, S.; Dias, J.; Ganhão, R.; Mendes, S.; Andrade, Mariana; Vilarinho, Fernanda; Sanches-Silva, A.; Alves, N.; Bernardino, S.

Aqueous extracts of commercially available red macroalgae Porphyra dioica were integrated as inner coatings of food-grade polypropylene (PP) films through use of electrospinning and electrospraying technologies. Two coating formulations (A = 5 wt% P. dioica extract and 7.5 wt% polyvinyl alcohol (PVA); B = 1 wt% P. dioica extract, 1 wt% PVA, and 17% gelatine) were evaluated as to their capacity to delay spoilage of minced chicken breasts, through monitoring of microbial growth (total mesophile aerobic colony counts), colour stability, lipid oxidation (thiobarbituric acid reactive substances (TBARS)), and sensory analysis over a 4-day refrigerated storage. Scanning electron microscopy (SEM) imaging revealed an increased nanofiber and nanoparticle density on extract-enriched fibers, without compromise to their morphology or the homogeneity of the coatings. Total microbial counts on coating B samples was significantly (p < 0.001) reduced compared to uncoated plastic wraps. The coated samples also exhibited fewer colour degradation, though the coatings did not di er substantially from uncoated plastic wrap. Sensory analysis test subjects successfully distinguished the raw samples based on their treatment and gave a positive approval rating (66.7%) to the extract-enriched coatings when asked about edibility post storage.

2020-03-26Journal article

Open access

Optimization of Extraction Conditions for Gracilaria gracilis Extracts and Their Antioxidative Stability as Part of Microfiber Food Coating Additives

Publication . Reboleira, João; Ganhão, Rui; Mendes, Susana; Adão, Pedro; Andrade, Mariana; Vilarinho, Fernanda; Sanches-Silva, Ana; Sousa, Dora; Mateus, Artur; Bernardino, Susana

Incorporation of antioxidant agents in edible films and packages often relies in the usage of essential oils and other concentrated hydrophobic liquids, with reliable increases in antimicrobial and antioxidant activities of the overall composite, but with less desirable synthetic sources and extraction methods. Hydroethanolic extracts of commercially-available red macroalgae Gracilaria gracilis were evaluated for their antioxidant potential and phenolic content, as part of the selection of algal biomass for the enrichment of thermoplastic film coatings. The extracts were obtained through use of solid-liquid extractions, over which yield, DPPH radical reduction capacity, total phenolic content, and FRAP activity assays were measured. Solid-to-liquid ratio, extraction time, and ethanol percentages were selected as independent variables, and response surface methodology (RSM) was then used to estimate the effect of each extraction condition on the tested bioactivities. These extracts were electrospun into polypropylene films and the antioxidant activity of these coatings was measured. Similar bioactivities were measured for both 100% ethanolic and aqueous extracts, revealing high viability in the application of both for antioxidant coating purposes, though activity losses as a result of the electrospinning process were above 60% in all cases.

2020-09-05Journal article

Open access