Visual Quality Measurements - Color & Browning
The measurement of product quality based on Tristimulus colorimetry and light absorption spectroscopy has been refined for use in food products.
Hach Ratio Turbidimeter Model 18900
Turbidity Measurements for Fluid Systems
Techniques for determination of cloud stability and fluid systems turbidity are used to evaluate product quality. A sensitive ratio turbidity meter enables assessment of fluid turbidity regardless of product color. This equipment is used for monitoring juice products involved in haze formation, generations of stable cloud emulsions, and the impact of other factors related to shelf stability.
Spectroscopy
Spectrophotometers are used to monitor specific wavelengths related to visual phenomena in fruit and vegetables. Browning reactions in fruit and vegetable extracts are tracked typically at 420nm. Multiple end-products resulting from enzymatic reactions associated with fruit browning have also been monitored through the use of a diode array detector.
Hunter Model D25 PC2D Colorimeter
Plot of experimental treatments to reduce browning in dried apple slices
Hunter Tristimulus Colorimetry
Measurement of color and mapping to uniform color is carried out with the Hunter Tristimulus Colorimeter. Calculations of Hue and Chroma can be plotted on a polar coordinate system. Samples studied for changes in visual quality include: whole fruit in harvest maturity studies, skin vs. flesh maturation studies, and changes in processed product quality for slices, purees and juices. The Hunter Colorimeter has been particularly useful in mapping the effects of process variations as illustrated in the above plot of hue and chroma for dehydrated apple slices treated to reduce browning.
Contact:
Dr. Chang Y. Lee - (Tel: 315-787-2271) Email: Chang_Lee@Cornell.edu