Impact of Olive Extract Addition on Corn Starch-Based Active Edible Films Properties for Food Packaging Applications

Abstract

Active edible films based on corn starch containing glycerol as a plasticizer and an olive extract obtained from Spanish olive fruit (Olea europaea) by-products (olive extract; OE) at different concentrations (0, 0.05, 0.1 and 0.2 wt%) were prepared by using the casting technique and further solvent-evaporation. OE showed high total phenolic and flavonoids contents and antioxidant activity, which was evaluated by using three different methods: free radical scavenging assay by (1, 1-Dipheny l-2-picrylhydrazyl) DPPH, 2, 2-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ABTS radical inhibition and ferric reducing antioxidant power (FRAP). The incorporation of OE into the corn starch/glycerol matrix underlined the antioxidant potential and antimicrobial effect against E. coli and S. aureus of these novel active films, being noticeable for films added with 0.2 wt% OE. The developed active films showed a clear thermo-oxidative stability improvement with OE incorporation, in particular at 0.2 wt% loading with an increase of around 50 °C in the initial degradation temperature (Tini) and oxidation onset temperature (OOT). The functional properties of control films were also improved with OE addition resulting in a decrease in Young’s modulus, elongation at break, shore D hardness and water vapor permeability. The present work suggested the potential of the developed corn starch-based edible films as low-price and sustainable food packaging systems to prevent the oxidative deterioration of packaged foodstuff while reducing also the generation of olive by-products.

Hydroxytyrosol and Oleuropein-Enriched Extracts Obtained from Olive Oil Wastes and By-Products as Active Antioxidant Ingredients for Poly (Vinyl Alcohol)-Based Films

“…In accordance with the results of TGA characterization ( Figure 6 ), where we found thermal degradation of OleE and HTyrE beyond 130 °C [ 46 ], and by considering that PVA needs to be heated up to 240 °C to clearly identify its thermal behavior, we limited DSC analysis to a first heating scan. In fact, heating to 240 °C of PVA films loaded with OleE and HTyrE will induce thermal degradation of the extracts, altering the thermal response of the PVA matrix.…”

Multilayer Films Based on Poly(lactic acid)/Gelatin Supplemented with Cellulose Nanocrystals and Antioxidant Extract from Almond Shell By-Product and Its Application on Hass Avocado Preservation

“…The colour properties of the films were determined, in triplicate, with a Konica CM-3600d spectrophotometer (Konica Minolta Sensing Europe, Valencia, Spain) using the CIELAB colour notation system, according to Valdés et al [22].…”

“…Three tensile parameters (elastic modulus, tensile strength and elongation at break) were obtained from the stress-strain curves using a 3340 Series Single Column System Instron Instrument, LR30K model (Lloyd Instruments Ltd., Fareham Hants, UK), as described in a previous work [22].…”

Functionality and Applicability of Starch-Based Films: An Eco-Friendly Approach

“…It was observed that the addition of a lipid component would result in a significant increase in the film water-barrier properties (reduce moisture sorption) and affect the mechanical and oxygen barrier properties. On the contrary, in the case of film-forming emulsions obtained by casting method, the incorporation of the essential oil (cinnamon or ginger) in the starch-sodium caseinate films provoked a slighter increase in the oxygen permeability values due to the rise in oxygen solubility in the oil, and slightly reduced water vapor permeability [88][89][90]. This opposite behavior could be attributed to the lower content of plasticizer used; therefore, where fewer OVP values are required, glycerol could be recommended for film preparation.…”