--1. Introduction

The Brassica family is a group of vegetables widely consumed around the world, including cabbages, cauliflower, Brussels sprouts, radishes and broccoli (Brassica oleracea L. var. italica) among others [1]. In the last few years, the consumption of cruciferous foods in Spain has increased. Specifically, the consumption of broccoli has undergone a significant rise, with a positive effect on the agricultural economy, particularly in the Murcia region (southeastern Spain), which is the region with the greatest production of broccoli in Europe [2,3]. This rise in consumption is related to increased adherence to healthier diets by European consumers, since this family of vegetables, and particularly broccoli, has high contents of fiber, minerals and vitamins, and is an important source of bioactive compounds with high antioxidant activity (carotenoids, phenolic compounds and glucosinolates) [4].

2. Influences

Although a single serving of broccoli provides a wide range of phytochemicals with beneficial effects for human health [1], the contents of these compounds vary depending on physiological, genetic and agronomic factors (including the cultivar, soil composition, agronomic treatments, climatic conditions and pre- and post-harvest treatments [5,6]). Carotenoids, one of the characteristic groups of compounds in broccoli, are natural pigments derived from the isoprenoid pathway, and are formed of a C40 backbone that differs according to the specific carotenoid being considered [7]. Carotenoid content can vary in broccoli plants as a result of environmental conditions—mainly temperature and sunlight [8,9]—while genetic factors and treatment applications can also affect the content [10]. Moreover, the content varies among the distinct parts of the plant, being higher in florets than in stalks [11]. The major carotenoids found in broccoli are β-carotene and lutein [12]. Phenolic compounds comprise one or more aromatic rings attached to hydroxyl groups [13]. Quercetin and kaempferol are the main flavonol glycosides, whereas chlorogenic and sinapic derivatives are the main hydroxycinnamic acid derivatives found in broccoli [14,15]. Glucosinolates (GLSs) are constituted by a thioglucose group, a sulphonated oxime group and a side chain derived from methionine, phenylalanine, tryptophan or a branched-chain amino acid [16]. Glucoraphanin (GRA), glucoiberin (GIB) and glucobrassicin (GBS) are the major GLSs in broccoli [17,18], and their breakdown products are important due to their health-promoting activity.

In vivo and in vitro studies have associated the consumption of broccoli and its phytochemicals with a reduction in the risk of suffering metabolic syndrome (obesity, diabetes and dyslipidaemia) and some types of cancer (lung, stomach, colon and rectal) [19–21]. For this reason, there is increased industrial interest in the improvement of the synthesis and accumulation of these bioactive compounds in plants, which naturally varies due to physiological, genetic and agronomic factors [6,22,23]. With regard to improving the quality of the vegetables or the content of bioactive compounds, an increase in plant stress [6,24] can lead to a higher synthesis of these secondary metabolites.

This entry is adapted from the peer-reviewed paper 10.3390/foods9101371