pH colorimetric indicator based on plant material waste to monitor the spoilage process of protein materials

Document Type : Research Article


Analytical chemistry, Assistant professor, Department of Chemistry, Faculty of Basic Sciences, Golestan University, Gorgan, Iran


In the food industry that produces protein materials such as chicken, fish, sausage and sausage, currently protein products are one of the most perishable food sources that require the use of new packaging methods such as smart packaging that is capable of performing intelligent functions. In order to increase the shelf life, it has always been interesting to control and show the changes during the storage period and maintain the quality of the product. The purpose of this research is to provide a pH-dependent color sensor, which, in addition to being simple, is low-cost and non-toxic, in order to detect the spoilage of protein materials during storage. Tests for protein samples have been carried out at both room and refrigerator (4 ºC) temperature. To make this sensor, Whatman paper was used, impregnated with aqueous extracts of fruits and plants wastes. The growth of microorganisms during the storage of protein materials leads to the decomposition of protein and the producting of volatile amines, which accumulate in the packaging chamber and cause the environment to become alkaline, and as a result, changes in the color of accumulated filter paper with aqueous extract will change with pH change. These color changes were investigated using CIELab system analysis and photography. Also, determination of the measurement of thiobarbituric acid index values, measuring the total amount of volatile nitrogen released from protein substances during the storage period, measuring the total phenol of aqueous extracts obtained from plant wastes and the appearance changes of the samples, in order to consider the consistency of the appearance changes of the samples was performed. The obtained results confirm the consistency of the color change of the sensor with the progress of the corruption.


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