Melting Index Calculation and Gravimetric Analysis of Ice Cream Melting

To begin, download the images of melting ice cream captured by the digital camera setup to a computer. Then, in the image analysis software, click on File and Open to open the ice cream images. Start processing the first image and click on Edit and Rotate to adjust its rotation if necessary.

Then, zoom into the size reference and click on Measure, then Calibration, followed by Spatial. Next, click on Image to spatially calibrate the image. Move the scale over the size reference and calibrate the length to convert pixels to millimeters.

Next, click Edit, NEW AOI, and rectangular to select a rectangular area of interest that includes the ice cream sample avoiding the edge of the metal wire mesh screen. Crop this area and convert it to grayscale by clicking Edit, then Convert To and selecting Gray Scale. To apply the best fit filter, click on Enhance, then Equalize and Best Fit to automatically adjust brightness and contrast.

Then, open the Measure and Count/Size window and set the parameters of Area, Box Height and Box Width. Choose manual measurement in the Count/Size window and click on Select Ranges to set the histogram values to segment the bright shape of the ice cream. After closing the Segmentation window, click on Count in the Count/Size window of the software to measure the parameters.

View the results by clicking on View and Measurement Data. Then click on File and Data to Clipboard to copy these results and paste them into a data management software spreadsheet To evaluate the melting index, use this equation on the H and W data at different melting times to calculate the shape retention index. Refer R and A data at each time point to the corresponding index at time zero, and plot these results over time according to these equations.

For gravimetric data analysis, save the spreadsheet with the weight of the melted sample per minute. At the end of the 90-minute melting trial, open this spreadsheet in data management software to create a melting curve showing the melted weight over time. Select data from the linear portion of the melting curve to calculate the least squares regression line and the regression coefficient.

The slope of this line represents the ice cream melting rate in grams per minute. Calculate the starting time of melting as the x-intercept where y is zero. Using this protocol, melting behavior was analyzed for ice creams made with different sweeteners such as sucrose, sucromalt, and erythritol.

Shape retention curves showed that ice cream made with sucrose lost its shape faster than the others, whereas the ice cream made with erythritol kept its shape until the end of the trial. Similarly, area retention curves showed that ice cream containing erythritol showed a lower meltdown rate compared to ice creams with sucromalt and sucrose. Further, gravimetric analysis showed that the ice cream containing erythritol showed the highest melting starting time and lowest melting rate out of the three samples.