Application of a Texture Analyzer friction rig to evaluate complex texture attributes in apples

• Friction measurements correlated strongly with crisp, juicy and mealy across years. • Penetrometry produced strong correlations with crisp. • Penetrometry had only weak to moderate correlations with juicy and mealy. • Penetrometer correlations were more variable across years. • Friction measurement is complementary to penetrometry, particularly in lab settings. Penetrometer measures are widely used to measure apple firmness to estimate texture attributes such as crispness during apple evaluation. Unfortunately, other texture attributes particularly those related to mouthfeel, such as juiciness and mealiness, are not well captured by this approach. The present study investigated correlations between friction measurements completed on a friction rig attached to a Texture Analyzer and apple texture attributes. The results are compared to the performance of penetrometry using a Magness-Taylor probe attached to a Texture analyzer over the course of several harvest seasons. Results indicated that the friction rig produced moderate to strong correlations (0.68 to 0.76) with apple crispness, juiciness and mealiness and correlations were consistently observed across years. In agreement with previous work, correlations between friction measurements and texture attributes were strongest during the earlier strokes of the friction runs indicating that short runs would be effective. Penetrometer measurements completed on the same apple sets produced moderate to strong correlations (0.60-0.87) with crispness. However, correlations with mouthfeel attributes (juicy and mealy) were lower (0.37-0.68). Penetrometers have certain advantages such as being low cost and they can also be used in-field. However, friction measurement is recommended as a complementary tool that can be used in more advanced stages of apple screening once samples are brought into the lab from the orchard and a more complete assessment of apple texture is needed.