Easy Nitrite Analysis of Processed Meat with Colorimetric Polymer Sensors and a Smartphone App

Abstract

We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric filmshaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by only taking digital photographs of sensory films and analyzing digital color parameters. The film-shaped polymer sensor detects nitrite anions by an azo-coupling reaction, since they activate this reaction between two of the four monomers that the copolymer is based on. The sensory polymer is complemented with an app, which analyzes the color in two different digital color spaces (RGB and HSV) and performs a set of 32 data fittings representing the concentration of nitrite versus eight different variables, finally providing the nitrite concentration of the test samples using the best fitting curve. The calculated concentration of nitrite correlates with a validated method (ISO 2918(ISO : 1975 usually used to determine nitrite, and no statistically significant difference between these methods and our proposed one has been found in our study (26 meat samples, 8 prepared, and 18 commercial). Our method represents a great advance in terms of analysis time, simplicity, and orientation to use by average citizens.

International & Home News

“…Researchers in Spain at the Universidad de Burgos have developed an in situ methodology for determining nitrite concentration in processed meats that can be used by consumers 11 . It is based on a colorimetric film‐shaped sensory polymer that changes colour upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by taking digital photographs of sensory films and analysing digital colour parameters.…”

Democratization of Copper Analysis in Grape Must Following a Polymer-Based Lab-on-a-Chip Approach

“…Quality control in processed food products is an issue both related to food safety and to the organoleptic perception by the final user. Accordingly, it is gaining increasing relevance yearly, both in final products and in the intermediate production stages. − For example, a number of analyses are mandatory to pass specific controls and/or to determine the concentration of different markers in beverages such as wine and are related to different organoleptic properties, such as color, flavor, etc.…”

“…In this work, we propose the democratization of this type of analysis of copper in grape must by using a film-shaped smart sensory polymer that selectively interacts with copper and generates a color change. Furthermore, our proposal combines the use of the film with a free smartphone application, which analyzes the RGB parameters of the formed color. The material is mainly based on commercially available monomers (99.5 mol %), combined with a small amount (0.5 mol %) of a sensory monomer based on the chemical structure of a well-known copper chelating agent as bicinchoninic acid (BCA). , …”

Effect of Cold-Plasma-Treated Phosphate Solution to Substitute Partial Nitrite on the Color, Texture, and Flavor of Smoked Sausage

“…Nitrite is usually added to the smoked sausage, to improve the color, flavor, and anti-oxidation and antibacterial properties [ 3 , 4 , 5 ], but nitrite represents a potential hazard to humans, due to NO 2 - being directly associated with gastrointestinal tumors, stomach cancers, and certain diseases. In the human body, a concentration of 33–250 mg of nitrite per kilogram of weight is fatal, while a concentration of 0.4 to 200 mg of nitrite per kilogram of body weight is enough to cause methemoglobinemia [ 6 , 7 , 8 ]. Therefore, exploring nitrite replacement technologies is a common challenge in the meat industry.…”