Dried snack foods such as apple chips are a convenient alternative to fresh fruit, providing longer shelf life and easier storage. Consumers increasingly demand product variety, so companies coat such snack foods with fruit and vegetable powders to enhance taste and sensory appeal. A new study explores the drying process of coated and uncoated apple chips using near-infrared (NIR) spectroscopy to measure moisture content in real time. NIR technology greatly enhances the speed and accuracy of measurements, the researchers say.

A new study from the University of Illinois explores the drying process of coated and uncoated apple chips using near-infrared (NIR) spectroscopy to measure moisture content in real time. NIR technology greatly enhances the speed and accuracy of measurements, the researchers say.

The purpose of coating is to make dried apple chips more functional and nutritional, as well as more appealing to eat, explains Ragya Kapoor, graduate student in Food Science and Human Nutrition (FSHN) at U of I and lead author on the paper.

«The idea is to get school-aged children to include apple chips in their diet. We use a cranberry powder coating to make the apple slices more attractive in terms of color and taste,» Kapoor says. «We dip the apple slices in a liquid-based solution for 60 seconds twice, and then conduct the hot air-drying operation.»

The researchers check the moisture content at various points throughout the drying process with miniature NIR spectroscopy to ensure the chips are dry enough.

NIR technology offers many advantages compared to standard monitoring techniques, says Mohammed Kamruzzaman, assistant professor in the Department of Agricultural and Biological Engineering (ABE) at U of I and co-author on the paper.

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Materials provided by University of Illinois College of Agricultural, Consumer and Environmental Sciences. Original written by Marianne Stein. Note: Content may be edited for style and length.