Gelatin based films capable of modifying its color against environmental pH changes

YANINA MUSSO; PABLO SALGADO; ADRIANA N MAURI

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2016 vol. 61 p. 523 - 530

0268-005X

The aim of this work was to develop biodegradable protein-based films capable of sense pH changes.These protein films were prepared by casting from aqueous solutions of bovine gelatin, glycerol and threeacid-base indicators: methyl orange (MO), neutral red (NR) and bromocresol green (BCG), at pH 2, 6 and11. All resulting protein films were homogeneous, thin and had different colors depending on pH and theindicator used. The response of these materials was evaluated simulating their contact with liquid andsemisolid media, and with a container headspace at acid and alkaline pH. In all tests, developed proteinfilms could modify their color after being in contact with media of different pH. The physicochemicalproperties of films were also affected differently by the presence of each acid-base indicator. While theaddition of BCG did not significantly modify the properties of control gelatin films, except its color; theincorporation of MO and NR into film-forming solutions significantly improved mechanical propertiesand decreased the water solubility and moisture content of the resulting protein films without affectingtheir water vapor permeability.