Influence of organic cultivation and sampling year on quality indexes of sweet pepper during 3 years of production

Abstract

Two genotypes of sweet pepper were studied regarding their profile of quality indexes related to yield, taste and healthy components. The peppers were grown with three different types of cultivation, one conventional (CONV) and two organic (ORG), in three harvest years, 2015, 2016, and 2017. The two genotypes belong to the typology "red long horn", comparing a local cultivar selected for organic production (RTV), against a commercial F1 hybrid (Alceste F1). The main quality indexes of sweet pepper were measured, considering yield, tastants such as sugars, organic acids, volatiles and phytochemicals such as ascorbic acid, carotenoids, and tocopherols. Moreover, the Folin–Ciocalteu and DPPH assays were performed to assess the total polyphenols content and the antioxidant capacity. The results indicated that the 3 years of harvest were different, with the summer of 2016 more rainy and less warm than others, and most significant differences among the samples were due to this factor. The data collection indicates that ORG fruits had significant higher agronomic yield and sugar content, while higher content of ascorbic acid, yellow carotenoids, and Folin–Ciocalteu index was found in 2016 with respect to 2015 and 2017, in accordance with the meteorological variations. Moreover, in 2016, some volatiles showed strong depletions in ORG vs CONV samples. In some cases, considerable differences between the genotypes were observed, due to the different adaptability to ORG conditions for RTV and to CONV conditions for Alceste F1. A high content of free sugars and ascorbic acid was found in RTV ORG, while high content of organic acids, carotenoids, and 2-methoxy-3-isobutyl pirazine was observed in Alceste F1 ORG.