Submitted to: Pacific Basin Society Chemical International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 14, 2001
Publication Date: N/A
Technical Abstract: Demand for fresh fruits and vegetables is increasing worldwide in response to health issues, enhanced economic conditions, and desire for variety in the diet. However, consumption of fresh fruits and vegetables is contingent on the industry's ability to provide high quality fresh produce that is safe, convenient, and economical. Texture is frequently the quality attribute that limits a consumers' willingness to use fresh produce. Texture is the human perception of the mechanical properties of the tissue, determined by structure and composition of the cell walls and by turgor. Instrumental measurements are preferred to human evaluations for research and commercial applications because instruments are more convenient, less expensive, and more consistent when used by different people. Different measurements detect different textural attributes. Firmness is the most commonly measured attribute, but is poorly defined and dmeasurements are mostly destructive. The most widely used texture measurement for produce is the Magness-Taylor fruit firmness test, which measures maximum force to puncture in a specified way. Fruits and vegetables exhibit viscoelastic behavior under mechanical loading, which means that the force, distance, and time involved in loading determine the value of any measurement. There are many modes of instrumental measurement; e.g., puncture, compression, torsion, extrusion, tension, vibration, and impact. Nondestructive methods being developed are based on vibrational behavior, small impacts or deflections, or light scatter, or on detection of compositional factors by optical technologies. Instrumental measurements can provide a common language among researchers, producers, packers, regulatory agencies, and customers.