Pre-harvest Cultural Growing Conditions Can Influence Carotenoid Phytochemical Concentrations in Vegetable Crops

Carotenoids are secondary plant metabolites that serve antioxidant functions in plant photosynthetic processes, as well as in actions of disease reduction in mammalian systems. The antioxidant activity associated with carotenoids is attributed to their unique chemical structures. The production of antioxidant compounds within plants can increase, or decrease, in response to various forms of environmental stress. Stress is a term used to collectively describe numerous conditions that can have negative impacts on plant performance. Stress responses form continuums from very rapid physiological changes to much slower morphological changes. Plant secondary metabolites, such as carotenoids, serve functional roles to overcome the negative consequences to plant growth and development caused by a stressful environment. Carotenoid accumulation appears to be shaped by a plant species’ physiological, genetic, and biochemical attributes, as well as environmental growth factors, such as light, temperature, and soil fertility. Pre-harvest cultural management factors will also influence the accumulation of carotenoids in plant foods. Carotenoid accumulations have been shown to change in response to environmental manipulations, which can increase stress imposed on the growing plants. Changes in the growing air temperature, irradiance level, irradiance photoperiod, and nutritional fertility regime can all influence plant carotenoid accumulations. Manipulation of cultural growing conditions and time of harvest will influence plant physiological status, which can determine phytochemical (carotenoid) concentrations present in fruit and vegetable crops.