Triggering mechanisms for oxygen-scavenging function of ascorbic acid-incorporated whey protein isolate films.

Background: Incorporation of ascorbic acid (AA) into whey protein isolate (WPI) films has been shown to increase the film's ability to protect foods from oxidation. The O₂-scavenging function of AA-WPI films could be triggered upon being placed in contact with food products. Several food-related factors hypothesized to act as triggering mechanisms for activating the O₂-scavenging function of AA-WPI films were investigated, including change of water activity (a(w)), pH and/or metal catalyst presence.

Whey protein film with oxygen scavenging function by incorporation of ascorbic acid.

Unlabelled: Residual O(2) in a package headspace can be removed by an O(2)-absorbing sachet, which can be harmful if swallowed by the consumer, or by a chemically-active plastic packaging film, which is difficult to recycle. An edible, O(2)-absorbing film would avoid these disadvantages. The objective of our research was to assess the O(2)-scavenging potential of an edible whey protein isolate (WPI) film incorporating ascorbic acid (AA).

Storage stability of ascorbic acid incorporated in edible whey protein films.

The stability of ascorbic acid (AA) incorporated in whey protein isolate (WPI) film and the related color changes during storage were studied. No significant loss of AA content was found in any films prepared from pH 2.0 casting solution stored at 30% relative humidity (RH) and 22 °C over 84 days.

Whey protein-polysaccharide blended edible film formation and barrier, tensile, thermal and transparency properties.

Background: Films made from different protein (P) or polysaccharide (PS) materials have widely different properties. The objective of this study was to determine whether whey protein isolate (WPI)-PS blended films possess a combination of properties intermediate and possibly superior to WPI or PS film alone.

Results: Oxygen permeability (OP) and tensile strength (TS) for PS-WPI blended films were intermediate between the OP and TS properties of pure methycellulose (MC), hydroxypropylmethylcellulose (HPMC) or sodium alginate (SA) film and pure WPI film.

Whey protein-okra polysaccharide fraction blend edible films: tensile properties, water vapor permeability and oxygen permeability.

Background: A hot-buffer-soluble-solid fraction (HBSS) and an alkaline-soluble-solid fraction (ASS) of okra polysaccharides (OKP) were obtained using sequential extraction. These fractions were combined with whey protein isolate (WPI) and glycerol (Gly) plasticizer to form blend edible films. Effects of OKP fraction and content on tensile properties, water vapor permeability (WVP) and oxygen permeability (OP) were determined.