Morpho-structural description of epidermal tissues related to pungency of Capsicum species

Chili peppers (Capsicum spp.) production is important worldwide due to its capsaicin contents. This work aimed to evaluate morphometrics of chili pepper tissues and in the formation of ampullas (structures related to pungency) by digital image analysis (DIA). Structural changes of epidermis in pungent chili peppers “habanero” and “jalapeno” were evident at 15 and 31 dpa (days post-anthesis), respectively, while in “bell pepper” (no pungent), only minor changes were observed during 82 dpa. Fractal dimension (Fd) and lacunarity (Λ) values of cropped tissue images were useful to distinguishing between pungent on one side and intermediate and non-pungent varieties on the other. Correlations between fractal areas of evaluated tissues were high for “jalapeno” and “bell pepper” while for “habanero” no correlation was found. Linear regressions and significant correlations between Fd and Λ indicated that DIA morphology characteristics are related to ripening stages, thus indicating commercialisation and processing possibilities.