stress (Frost et al. 2008). Plants are not only a source of carbohydrates, proteins,
and fats for food but also they are a valuable source of a wide range of secondary
metabolites (Gry et al. 2007). These metabolites are needed by plants to defend
themselves in a hostile environment (protection against predation, protection
against fungal and bacterial diseases, or against adverse climatic conditions), but
also they are useful to herbivores like humans, because they have beneficial effects
on health (Rea et al. 2010). For this reason, phytochemicals with bioactive
properties are attracting increased interest from consumers. Hence, improvements
in agricultural practices, as mentioned before, should focus not only on yield, but
also on the maintenance and/or augmentation of bioactive phytochemicals present
in plants.
Epidemiological studies have demonstrated an inverse association between fruit
and vegetable intake and chronic diseases (Alwan 2011). Some secondary
metabolites have been indicated to be responsible for this observed protective
effect. Nevertheless, population studies have demonstrated an inadequate consumption of fruit and vegetable. To increase consumption of fruit and vegetables
has been a public health effort for years, but with minimal success. As the amount
of fruits and vegetables does not seem to increase, it results in an approach that the
development of fresh product containing a greater concentration of phytochemicals
with biological activity. Controlled greenhouse environments provides an opportunity to modify not only the concentration of phytochemicals in fruit and vegetables but also the yield (Kubota et al. 2006). However, further knowledge to
improve this practice is still needed.
Although the presence of bioactive compounds in vegetables and fruits depend
both quantitatively and qualitatively on their genetic bases (Hervert-Hernández
et al. 2010), they could be increased through modifications of environmental
conditions and crop management strategies (fertilization, efficient water management, and techniques such as grafting). It is known that even the maturity state of a
fruit or vegetable, harvest time, postharvest storage, and processing could
affect the amount of secondary metabolites present in agricultural products
(Ghasemnezhad et al. 2011).
Fertilization and agronomic condition such as organic and inorganic soil
composition are relevant factors that affect not only crop yield, but also quality
(Martínez-Ballesta et al. 2008). For example, sulfur and nitrogen fertilization has
an impact in the plant glucosinolate content. An increased sulfur supply has been
shown to result in higher levels of total glucosinolates. High N supply delayed the
accumulation of phenolic compounds. Marín et al. (2008) report that sweet peppers grown in a greenhouse in a soil-less system showed similar or even higher
concentrations of antioxidant compounds (vitamin C, provitamin A, total carotenoid, hydroxycinnamic acids, and flavonoids) than organic peppers. Chassy et al.
(2006) indicate that no cropping systems differences exist between organic and
conventional managed bell pepper, nonetheless it is also mentioned that these
differences are difficult to establish due to uncontrollable conditions such as
region, climate, soil quality, occurrence, and prevalence of pests and diseases.
Conversely, Kim et al. (2010) reported in both green and red fruits, the ascorbic
32
L. Garcia-Mier et al.
and fats for food but also they are a valuable source of a wide range of secondary
metabolites (Gry et al. 2007). These metabolites are needed by plants to defend
themselves in a hostile environment (protection against predation, protection
against fungal and bacterial diseases, or against adverse climatic conditions), but
also they are useful to herbivores like humans, because they have beneficial effects
on health (Rea et al. 2010). For this reason, phytochemicals with bioactive
properties are attracting increased interest from consumers. Hence, improvements
in agricultural practices, as mentioned before, should focus not only on yield, but
also on the maintenance and/or augmentation of bioactive phytochemicals present
in plants.
Epidemiological studies have demonstrated an inverse association between fruit
and vegetable intake and chronic diseases (Alwan 2011). Some secondary
metabolites have been indicated to be responsible for this observed protective
effect. Nevertheless, population studies have demonstrated an inadequate consumption of fruit and vegetable. To increase consumption of fruit and vegetables
has been a public health effort for years, but with minimal success. As the amount
of fruits and vegetables does not seem to increase, it results in an approach that the
development of fresh product containing a greater concentration of phytochemicals
with biological activity. Controlled greenhouse environments provides an opportunity to modify not only the concentration of phytochemicals in fruit and vegetables but also the yield (Kubota et al. 2006). However, further knowledge to
improve this practice is still needed.
Although the presence of bioactive compounds in vegetables and fruits depend
both quantitatively and qualitatively on their genetic bases (Hervert-Hernández
et al. 2010), they could be increased through modifications of environmental
conditions and crop management strategies (fertilization, efficient water management, and techniques such as grafting). It is known that even the maturity state of a
fruit or vegetable, harvest time, postharvest storage, and processing could
affect the amount of secondary metabolites present in agricultural products
(Ghasemnezhad et al. 2011).
Fertilization and agronomic condition such as organic and inorganic soil
composition are relevant factors that affect not only crop yield, but also quality
(Martínez-Ballesta et al. 2008). For example, sulfur and nitrogen fertilization has
an impact in the plant glucosinolate content. An increased sulfur supply has been
shown to result in higher levels of total glucosinolates. High N supply delayed the
accumulation of phenolic compounds. Marín et al. (2008) report that sweet peppers grown in a greenhouse in a soil-less system showed similar or even higher
concentrations of antioxidant compounds (vitamin C, provitamin A, total carotenoid, hydroxycinnamic acids, and flavonoids) than organic peppers. Chassy et al.
(2006) indicate that no cropping systems differences exist between organic and
conventional managed bell pepper, nonetheless it is also mentioned that these
differences are difficult to establish due to uncontrollable conditions such as
region, climate, soil quality, occurrence, and prevalence of pests and diseases.
Conversely, Kim et al. (2010) reported in both green and red fruits, the ascorbic
32
L. Garcia-Mier et al.