Pectin active films incorporated with Morinda citrifolia extract: antioxidant effect

Food industry has been looking for the innovation of food packaging’s field in order to fulfil the growing consumer demands for biodegradable materials, for food without chemical addition, preserving the sensory food qualities, the nutritional properties and the food microbiological security. To satisfy these consumer demands, active packaging have been produced by the incorporation of plant extracts into food packages to extend a product’s shelf life. Noni (Morinda citrifolia Linn) is Southeast Asia’s fruit which contains bioactive compounds that present anti-inflammatories, antioxidants and antimicrobials properties and the fruit is obtained by plant extracts. In this context, this study proposed to produce an active biodegradable films by the noni aqueous extracts (EAN) incorporation in pectin matriz (2% w/v) using polyethylene glycol (10% w/w) as plasticizer. The active films were prepared by casting method using different concentrations of EAN (T1-0%, T2-100% and T3-50%). The films’ properties, such as color, thickness, antioxidant activity in vitro (DPPH • and ABTS • +) and antimicrobial activity against Escherichia coli and Staphylococcus aureus (halo-diffusion test) were evaluated for films’ characterization. The average EAN’s data was 142.60 ± 1.5 mg for gallic acid equivalent/100g pulp, 17.10 ± 17.55% for free radical capture inhibition by ABTS•+ method and 13,.59 ± 0.16% by DPPH • methods in 1.20 mg.ml-1 of noni’s extracts. As regards to EAN’s films, the treatment with 100% of extract addition presented higher values for chromaticity parameters a* (4.56 ± 0.88), b* (24.56 ± 0.47) and yellow index (50.52 ± 2.5), and lower value for the L* coordinate (88.41 ± 2.12), differing significantly from treatments T1 (0% of EAN) and T3 (50% of EAN). The EAN films’ thickness were affected by the extract addition and T2 and T3 thickness values were significantly higher than T1. The EAN films’ did not present antimicrobial properties for the bacteria tested in this study, and this behaviour could be observed by halo-diffusion test because this active packagings were not able to inhibit the E. coli and S. aureus growth. In relation to DPPH• free radical capture for EAN films, there was a significant difference among the treatments evaluated and the percent inhibition was 0.82 ± 0.55% for T1, 47.56 ± 14.50% for T2 and 30.90 ± 3.62% for T3. It was observed that the film control (T1) presented the lowest DPPH• values than the other treatments containing extract in the films’ formulation indicating that the antioxidant properties were due to the Noni extracts addition in pectins matriz. Free radical capture inhibition data for EAN films using ABTS•+ method presented that T2 differed significantly from the other treatments (T1 and T3). Even if T1 and T3 were not significantly different, a higher percentage was observed for T3 (6.84 ± 3.83%) compared with the T1 (0.72 ± 2,13%). In this study, it was observed that the noni extracts presented expressive antioxidant activities and the production of active packagings by noni extracts incorporation in pectin matriz was a viable alternative to minimize the lipid oxidation effects in food packaged.

Financial support: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).