September / October, 2004

Graduate Research – Nicholas C Tipper

Subject: Non-destructive Firmness Measuring Device
for the Quality Assessment of Apples

Major: Biosystems Engineering

The firmness of an apple is a key attribute to knowing the quality, maturity, and value of the crop. The current industry standard for measuring the firmness (Magness-Taylor test) punctures the apple, greatly reducing its value. Methods that measure firmness without damage to the apple could lead to improved prediction of harvest time, online quality inspection, improved storage conditions and handling, and general improvement of consumer satisfaction.

My research will continue that of Dr. Hussain Ababneh, Dr. Renfu Lu, and Dr. Ajit Srivastava. The research involves the measurement of the bioyield point to determine the firmness of an apple. The measurement procedure of the bioyield point is similar to that of a Stress-Strain test except the test stops at an initial stress peak. This peak correlates to the apple’s structure compressing and the cellular structure beginning to burst. The key element to performing a successful test is the use of a specifically designed rubber tip. This maximizes the contact area with the apple, providing a uniform stress distribution. A successful measurement of the bioyield point incurs minimal damage the apple’s appearance and structure.

The bioyield probe I have constructed was designed for field use. I operates on battery power and runs on a stand-alone programmable microchip. This allows the collection of data without the need of a power source or computer connection to control the probe. After data collection has occurred, I can download the data to a computer for further analysis and record keeping. I intend to verify the design with several apple varieties by comparing results with the Magness-Taylor test. In addition, I may correlate the bioyield firmness to the maturity of the apple and moisture loss of the upper cellular layers. I hope that my results will provide accurate information about the quality of the apple and that my bioyield probe will become a useful tool for the industry.

Biosystems & Agricultural Engineering
Michigan State University
A.W. Farrall Hall
East Lansing, MI 48824-1323
(517) 355-4720

Questions or comments contact: webmaster

Past Newsletters | BAE Home | MSU Home

September 30, 2004