Colorimetric film sensor for monitoring rancidity reaction of intermediate-moisture (Cake)

Abstract

Colorimetric films sensor based on wheat gliadin with natural dyes (including anthocyanin, chlorophyll, and beta carotene), glucose oxidase, alpha amylase /starch / were created and for real-time monitoring cake formula rancidity reaction is described in this study. The addition Glucose oxidase enzyme 0.9% (activity270U/0.09g), 0.9% (117U/0.09g) of α-Amylase, and 5% of natural extracted pigments and concentration 1:0.1 of Gliadin/ glycerol composition films and starch greatly raised sensitivity the reaction of films to rancidity. The mixture of enzymes and substrate has a great impact on changing the intensity of color films. In addition, when the color attributes of the active film are examined, it is discovered that the color of the chlorophyll film changes (from green to yellow) whereas, beta –carotene film from (yellow to pale yellow) and Anthocyanin film (alterated from red to brown) with increasing storage duration and oxidant percent, which can be utilized to detect the rancidity reaction of cake's fat. The absorbance at 494, 450, and 666 nm, respectively, demonstrated that the intensity of anthocyanin, beta-carotene, and chlorophyll color films was greatly reduced as a result of rancidity reaction in cake samples after 3 weeks of storage at room temperature 30-35˚C and 25-30% of relative humidity. Moreover, all treated samples showed a decrease in color pigment intensity compared to the control after 15 minutes of exposure to peroxide hydrogen addition (1 ppm), the lowest concentration at which films are susceptible to oxidation. Furthermore, after 4 weeks of storage, samples of cakes, odor turned rancid under the same ambient conditions, and the cake's fat's peroxide value increased dramatically, from 1.3 to 8 mEqO2/kg were approximately close to the maximum permissible limit in Codex regulations therefore color of film sensor was changed fully as a result of increasing peroxide value and rancidity.

Keywords

• Colorimetric films, Rancidity, Glucose oxidase, Alpha amylase, Hydrogen peroxide, peroxide value (PV)