K. Duerrschmid, H. Yogurtcuoglu, G. Schleining

University of Natural Resources and Applied Life Sciences, BOKU Vienna, Department of Food Science and Technology, Division of Food Quality Assurance

Vegetables usually possess a very specific texture and must have matching acoustic properties. In front of this background suitable instrumental test methods and settings were developed to characterize cucumber in terms of textural and acoustic properties and to facilitate distinction between cucumbers of different quality.  

Different varieties of cucumber stored under different temperatures were eaxmined by a penetration and a cutting test using a SMS TA-XT2i Texture Analyzer from Stable Microsystems Inc. (cylinder probe Ø=6mm and cutting probe l=10 cm). Acoustic Measurements were performed with a Bruel and Kjaer microphone and an acoustic envelope detector using a lower limit of 3,125 kHz. Suitable settings to identify samples of different quality were as follows: For the penetration and cutting tests high test speeds (40 mm/s) performed best. The penetration of cucumber (test speed 40 mm/sec, distance 20 mm), showed the largest differences regarding different quality in the maximum force, in the linear distance and the number of peaks. The cutting test (test speed 40 mm/sec, distance 100 %) of cucumbers showed the largest differences in the parameters determined from the acoustics curve (maximum acoustic peak, linear distance and number of peak).

In conclusion our data show that acoustic measurements can contribute complementary information on the texture of tested samples. In many cases, acoustic analysis even reveals more details of the tested product than conventional texture measurement.