ABSTRACT
A colorimetric pH indicator was developed using nanofibers of poly(lactic acid) (PLA) and polyethylene oxide (PEO) combined with biomass of the microalga Spirulina sp. LEB 18. This study evaluates the potential use of microalgal biomass encapsulated in polymer nanofibers to develop a colorimetric pH indicator. Nanofibers containing the biomass were exposed to solutions with different pH values (pH 1-10), and color variations were measured using a colorimeter. The wettability analysis of the nanofibers showed hydrophilicity (zero angle with water), which allows ions to interact with the biomass, indicating a fast color response as a function of pH. When subjected to pH variations, indicators containing 1, 2 or 3% (w v-1) of biomass provided ΔΕ values >12, indicating an absolute difference in color. Therefore, this innovative material has the potential to be applied as a intelligent indicator to verify food quality through a visual signal of the product condition.
Subject(s)
Colorimetry/methods , Nanofibers/chemistry , Spirulina/physiology , Biomass , Color , Hydrogen-Ion Concentration , Polyesters/chemistry , Polyethylene Glycols/chemistry , WettabilityABSTRACT
This paper presents the development of a new smart time-temperature indicator (TTI) of pasteurization whose operating principle is based on the complexation reaction between starch and iodine, and the subsequent action of an amylase on this complex causing its discoloration at a rate dependent on time and temperature of the medium. Laboratory simulations and tests in a manufacturing plant evaluated different enzyme concentrations in the TTI prototypes when exposed to pasteurization conditions. The results showed that the color response of the indicators was visually interpreted as adaptive to measurement using appropriate equipment, with satisfactory reliability in all conditions studied. The TTI containing 6.5% amylase was one whose best results were suited for use in validating the cooking of hams. When attached to the primary packaging of the product, this TTI indicated the pasteurization process inexpensively, easily, accurately, and nondestructively.
Subject(s)
Amylases/metabolism , Cooking/methods , Food Microbiology/methods , Meat/microbiology , Pasteurization , Temperature , Animals , Color , Food Packaging , Hot Temperature , Humans , Iodine/metabolism , Meat/analysis , Meat Products/analysis , Meat Products/microbiology , Reproducibility of Results , Starch/metabolism , SwineABSTRACT
This study evaluated the applicability of a photochromic time temperature indicator (TTI) to monitor the time-temperature history and shelf life of chilled boneless chicken breast. The results showed that the smart indicator showed good reproducibility during the discoloring process in all the conditions investigated. The response was not only visibly interpretable but also well adaptable to measurement using appropriate equipment. For an activation configuration of 4 s of ultraviolet light (UV) per label, the TTI's rate of discoloration was similar to the quality loss of the meat samples analyzed. Thus, the photochromic label (4 s UV/label) attached to the samples set out to be a dynamic shelf-life label, assuring consumers the final point of quality of chilled boneless chicken breast in an easy and precise form, providing a reliable tool to monitor the supply chain of this product.
