Antioxidant Seasonal Changes in Soilless Greenhouse Sweet Peppers

Neocleous Neocleous,Nikolaou Nikolaou

doi:10.3390/agronomy9110730

Neocleous Neocleous, Nikolaou Nikolaou

Open Access

https://doi.org/10.3390/agronomy9110730

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Abstract

This study was commissioned to study the effect of the growing season on the antioxidant components of greenhouse sweet pepper crops, which is of scientific interest because of their possible beneficial health effects. The total antioxidant activity (estimated by ferric reducing antioxidant power-FRAP assay) major antioxidants (ascorbic acid, phenolics and carotenoids) and taste fruit quality characteristics (soluble solids, titratable acidity, dry matter and sugars) were recorded in soilless-grown sweet pepper cultivars of red, orange, yellow and green color at four harvesting season months, i.e., February (winter), May (spring), July (summer) and October (autumn). The results showed seasonal variations in antioxidant components and activity of pepper fruits. In most cases measured parameters showed higher values in spring (May) and summer (July) compared with winter (February) and autumn (October) growing seasons. This study indicates that during late autumn and winter, lower levels of solar irradiance, ultraviolet radiation and temperature in Mediterranean greenhouses can be insufficient to stimulate phytochemicals production in peppers; thus, plant–light interception must be more actively managed.

Highlights

IntroductionIn the United States consumption of fresh bell peppers (Capsicum annuum L.) increased up to 20% the last decade and averaged 11.2 pounds per person in 2018 [1]
Peppers are among the most consumed vegetables worldwide
Board of the Institute of Medicine in the United States as cited in [37], this study clearly shows that the challenge to eliminate nutritional variations all year round of the selected crops is fundamental

Summary

Introduction

In the United States consumption of fresh bell peppers (Capsicum annuum L.) increased up to 20% the last decade and averaged 11.2 pounds per person in 2018 [1]. Bell peppers have become one of the most important cultivated fruiting vegetable in Mediterranean greenhouses. Solanaceous crops (tomato, pepper and eggplant) constitute about 60% of greenhouse-cultivated areas, which are often cultivated in soilless culture to enhance yield, product quality, water use efficiency and sustainability [2,3]. Peat-based substrates are most widely used in fruiting vegetable production systems, rockwool is still the dominant soilless culture system in Europe [4]. Alternative ecofriendly substrates (e.g., biowaste materials) with a lower carbon footprint coupled with soilless culture systems may be considered as a useful tool in sustainable greenhouse horticulture [5]

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