Real-Time Monitoring of Rancidity in Granola Foods: A Study Using Peroxide Value and Colorimetric Sensors

One of the main causes of food quality and product degradation is lipid oxidation. It is known that a significant problem with the preservation of fatty acids in food products is lipid oxidation. Therefor this research explored the potential of granola products to develop rancidity by analyzing peroxide value (PV) and implementing smart packaging solutions. The PV method functions as a reliable quality index for the early stages of lipid oxidation. It was evaluated using six granola samples. The findings revealed a notable rise (p < 0.05) in PV from baseline levels (0.2 to 0.6 mEq O₂/kg) after storing the samples for two weeks at 32.5 ± 2.5°C and 27.5 ± 2.5% relative humidity, confirming the progression of rancidity. Furthermore, moisture content, which is a key determinant of food quality, showed a significant rise (p < 0.05) during storage, underscoring the absorption of moisture and its detrimental effect on shelf life. To enable real-time rancidity monitoring, smart packaging with natural dyes (anthocyanin and chlorophyll) was used. The chlorophyll-based indicators shifted from green to yellow, while anthocyanin-based indicators changed from red to brown when exposed to H₂O₂. Over the two-week period, significant decreases (p<0.05) in absorbance were recorded for chlorophyll (from 1.803 to 0.383) and anthocyanin (from 1.757 to 0.75). The color changes corresponded with increasing PV levels, offering a visual cue for granola quality decline. Using of smart labels on granola packaging successfully demonstrated real-time visual monitoring of product quality, consistent with earlier studies on colorimetric methods for detecting rancidity in food. The combined approach presents a practical alternative to conventional analytical methods, enhancing storage strategies and maintaining product quality.