S. Pandova¹, D. Mihaylova², A. Popova3, S. Savchovska¹, A. Zhivondov¹

1Department of Breeding and Genetic Resources, Fruit Growing Institute, 4000 Plovdiv, Bulgaria
2Department of Biotechnology, Technological Faculty, University of Food Technologies, 4002 Plovdiv, Bulgaria
3Department of Catering and Nutrition, Economics Faculty, University of Food Technologies, 4002 Plovdiv, Bulgaria

(Manuscript received 10 June 2022; accepted for publication 11 March 2023)

Abstract. The present study tracks changes in the development of two native peach varieties (“Laskava” and “Evmolpiya”) from fruit formation to full ripening within five calendar weeks. In search for a non-destructive method for maturity assessment, the parameters firmness, color, size, weight, dry weight, ash content, and TSS values were evaluated. It was found that a 30% increase in size and a 1.8-2 times increase in weight occurred during the ripening period. The TSS data did not change radically, which shows that the main nutrients of the peach accumulate in the early stages of development. The color indicators change in the following trend: a decrease in the “L”, “h” and “b” values, and a tendency of increase in the “c” values. The stone size does not change drastically during the evaluation time. The moisture content also does not change significantly, although in the initial stage of fruit growth it cannot be characterized by juiciness. Firmness progressively decreases.
The obtained results show grounds for the creation of a database of expected markers which may indicate the onset of maturity without the fruit being pulled from the tree or damaged.