Health Benefits of Broccoli. Influence of Pre- and Post-Harvest Factors on Bioactive Compounds

Abstract

Broccoli (Brassica oleracea L. var. italica) is a well recognized health-promoting vegetable due to its high beneficial compound content. Numerous epidemiological studies indicate that Brassicas, in general, and broccoli in particular, protect humans against some diseases since they are rich sources of glucosinolates as well as possessing a high content on flavonoids, vitamins and mineral nutrients. Glucosinolates are characteristic Brassicaceae compounds that, when the tissue is damaged, are hydrolysed by myrosinase to biologically active isothiocyanates such as sulforaphane, indole-3-carbinol and phenethyl isothiocyanate, the most responsible compounds of the anticancer activity of broccoli. Also, other phytochemicals, such as phenolic compounds and vitamin C have demonstrated antioxidant activity that protect against free radicals such as reactive oxygen species in the human body so that these have also been strongly associated with a reduced risk of chronic diseases. Accordingly, many studies have been done in order to determine the different factors that could affect these bioactive compounds. These factors could be classified into pre- and post- harvest aspects. The first group implies agronomic and environmental conditions or genetic and ontogenic factors. Thus, genotype, temperature, light radiation, fertilization, irrigation water, as well as age and harvesting time are the most important pre-harvesting factors, which may affect the bioactive composition of broccoli. The post-harvest group of factors such as packaging, storage, preservation, transport, and cooking processes have been widely reviewed and thus this review is focused on the wide bioactive content of broccoli and how the pre-harvest and post-harvest factors affect these health promoting phytochemicals.