Fig 1.
Cuvette image of the milk sample treated.
Example of capture strategy using a common smartphone.
Fig 2.
Spots of the region of interest (ROI) for image processing.
Here we denote the 2 ROIs as the blank (left) and sample (right).
Fig 3.
LPO calibration curve in units mL-1.
Calibration curve for lactoperoxidase analysis showing the absorbance vs lactoperoxidase concentration. Adjusted R2 = 0.98.
Fig 4.
Multivariate data analysis comparing milk treated samples and RGB channels.
Principal Component Analysis (PCA) model biplot of variables in Jersey (J), Gir (GI), and Guzerat (GU) milk samples with autoscaling.
Fig 5.
Enzyme activity calibration curve.
Lactoperoxidase analysis showing the predicted activity (y-axis) vs measured activity (x-axis) and the correlation between the proposed method for quantifying lactoperoxidase and the reference method. Adjusted R2 = 0.96 by multiple linear regression.
Fig 6.
Multiple linear regression for CCS.
Image processing analysis of predicted (RGB) vs. measured CCS. Adjusted R2 = 0.97.