**1. Introduction**

The title of this chapter is a translation of a local saying in Galicia (Northwest of Spain) that literally states in the Galician language, "Os pementos de Padrón, uns pican e outros non". The saying refers to the typical local dish consisting of green, immature fruits of pepper fried in oil and salted. When a dish of these peppers is served, you find that most fruits are sweet or mild, but sometimes you eat one that is extremely hot by chance. Padrón pepper production is of great economic relevance not only in Galicia but also in other parts of Spain, and even it is produced in other countries like Marocco (**Figure 1**).

These pepper fruits belong to a local landrace called "Padrón," which is characterized by the presence of capsaicinoids (the pungent substances in peppers), but in low amounts when fruits are immature [1]. The origin of the landrace can be traced back from the seeds that were taken in the 17th Century from Tabasco (Mexico) to the monastery of Herbón (a place in the municipality of Padrón) by monks of the Franciscan order [2]. The monks transferred seeds to the local farmers. The landrace arose from local breeding and established the tradition of restricting seed transfer within the local community. Interestingly, Padrón seeds are always part of women's dowry.

### **Figure 1.**

*A). Commercial bag of PDO "Pemento de Herbón" with the PDO label. B). Three different labels of Padrón commercial brands.*

### **Figure 2.**

*Commercial products include Padrón peppers as an ingredient or as a motto. A) Paprika powder made with PDO Herbón peppers. B) PDO Herbón pepper jam. C) Hot candies. D) PDO Herbón chocolates. E) Padrón pepper sauce mimicking tabasco. F) Padrón pepper liquor. G) t-shirt with a "Galician roulette" pun regarding the Galician saying. H) Socks. I) Key chain.*

The quality of the fruit, not only the heat but also other organoleptic traits, is considered of great importance by consumers. To guarantee this quality, some pepper growers in Padrón and other closer municipalities promoted the creation by the European Union of the Protected Designation of Origin (PDO) Pemento de Herbón, established in 2010.

On the other hand, the popularity of these peppers has led to the release of numerous commercial products, which include these peppers as an ingredient (paprika, jam, sauces, candies, chocolates, liquors, etc.) or items like t-shirts, socks, etc. as a part of Padrón-pepper passion (**Figure 2**).

Padron pepper consumers are divided into those who like such a pungency Russian roulette and those who prefer only sweet or hot fruits. Therefore, finding technical solutions to control the heat level is essential. Furthermore, it is not only a local issue: many other pepper landraces and cultivars are hot or sweet, and this trait has to be preserved when pepper lines are bred for, e.g., plant resistance to diseases, pests, and abiotic stress. Consumers expect a specific level of pungency (heat) in a particular cultivar's fruit, which has to be bear in mind to achieve success in sales. Moreover, even a pepper with the pungency (heat) trait can show a modulation of the level of capsaicinoids due to several factors [3].

This chapter reviews the present knowledge about pepper pungency and its control.
