Purple eggplant and zucchini color, mechanical properties, mastication, and sensory perception influenced by boiling...

The present study investigated the influence of boiling and grilling deployed at 15, 30, and 45 min on selected eggplant and zucchini qualities. The colorants present in these vegetables contribute to their attractive appearance while presenting health-benefit components. This study shows that boiling and grilling differently affected the color properties of the eggplant and zucchini flesh and skin, leading to discoloration. However, the multifactorial mechanisms behind this phenomenon are not yet fully uncovered. Both boiling and grilling caused softening in examined vegetables within cooking prolongation, but different effects were observed. In the case of grilling, large- and small-deformation mechanical parameters established higher values. Thus, grilling produced firmer samples, which was further projected on mastication and dynamic sensory perception. Although there was limited differentiation in mastication parameters, it was observable that grilled products were more mastication-demanding. The number of chews and consumption time provided most of the information and established higher values for short-time cooking treatments and grilling. As a consequence, samples that had longer in-oral exposure times were perceived as bitter (eggplant) or sweet (zucchini). Oppositely, boiled vegetables were juicier. Regardless of the type of vegetable or cooking method, the shortest cooking treatments resulted in products dominantly perceived as firm.