The influence of grape (Vitis vinifera L.) berry maturity on dried fruit colour

Abstract

SummaryThe grape cvs Sultana H5 and Merbein Seedless produced light coloured dried fruit after treatment with an alkaline, oil-in water emulsion prior to drying. Berries were harvested at different times during the harvest period to give a range in soluble solids in the fresh fruit from 18 to 26 °Brix. The colour was evaluated by the CIE L*a*b* colour system. Low and high soluble solids concentrations in fresh fruit resulted in brown dried fruit. The lightest dried fruit was produced when the average soluble solids concentration in fresh fruit was between 21 and 22°Brix for ‘Merbein Seedless’ and 21 to 23°Brix for ‘Sultana H5’Sultana H5’ dried fruit was slightly lighter than that of ‘Merbein Seedless’. At the higher levels, positive linear relationships between lightness and soluble solids concentration became negative for both cultivars. The results, which describe a “narrow window of opportunity” for the production of light coloured dried fruit, indicate that the timing of harvest is critical for quality. Overall the dried fruit quality of ‘Merbein Seedless’, which generally had an advanced maturity, was similar to sultanas produced from ‘Sultana H5’.