Effect of the application of vegetable extracts in pre- harvest in the Bordô grape cultivar

Abstract

This study aimed to evaluate the effectiveness of the application of different plant extracts in the postharvest quality in organic Bordô grapes cultivar (Vitis labrusca). For the preparation of the extracts were used the dried leaves of gervão (Stachytarphetta cayenensis) and capim-limão (Cymbopogon citratus); fresh leaves of pau dalho (Gallesia integrifolia) and wine residue (powder) from grape cultivar Isabel (Vitis labrusca).  Each extract was applied at a concentration of 12% directly to the clusters 10 days before harvest and a portion of grapes received beyond the field application a new application in postharvest. The experimental design was randomized blocks in a factorial scheme with 5 X 2 (5 treatments and pre-harvest and postharvest application) with 4 repetitions. Fruit quality parameters were assessed based on several criteria: color, pH, titratable acidity, maturation index, level of phenolic compounds, anthocyanins and sensory analysis. It was found that the extracts were effective to maintain acidity, soluble solids, maturation index and sensory analysis. However, the application of lemongrass (Cymbopogon citratus) extract applied in pre- and postharvest treatments maintained pH, chroma, anthocyanins levels and berries revealed a more intense color. The extract gervão (Stachytarphetta cayenensis) applied in pre- and postharvest kept a higher phenolic content when compared to the application only in pre-harvest.  Pre- and postharvest application of lemongrass extracts and gervão showed to be a good alternative treatment for quality maintenance during storage of grapes.