Plum fruits maturity indices and quality of plum brandy

Abstract

Certain plum cultivars are characterised by early development of blue skin colour, making it difficult to determine the right time to pick the fruits for the intended purpose of their use. This paper examines various maturity indices for fruits of the 'Čačanska lepotica' cultivar (firmness of fruit, fruit mass, stone ratio, soluble solids content, total sugars, and total acids content, pH value, value of individual pectin fractions, content of aromatic fruit components, as well as ratios between certain tested parameters) and their suitability as indicators of maturity level in fruits intended for the production of brandy. The fruits ripened on the tree and their picking for the intended brandy production was performed at four different degrees of ripeness, with the final harvest cycle being performed concurrently with the traditional harvest time for brandy plums (when fruits are fully ripe and slightly over-ripe). The same method of brandy processing was used with fruits from all four harvesting cycles. Brandies obtained in this manner were analysed for the contents of the most important volatile components (methanol, higher alcohols, ethyl acetate, acetaldehyde, benzaldehyde, and HCN). It was established that all of the produced brandies, regardless of the level of ripeness of plum fruits used in their production, fulfil the legal requirements regarding the levels of methanol, HCN, and total volatile components. Brandies produced using fruits of second and third level of maturity were granted higher sensory markings than fruits produced from the most mature plum fruits (fourth level of maturity), which are traditionally used in brandy production.