Study of the Influence of the Ripeness Degree of Parsnip Roots and Storage Method on Their Preservation

Abstract

Sowing parsnip is recommended to be harvested in the stage of technical ripeness that takes place in 120–150 days after sprouts. A ripeness degree cannot be determined by a root size, because in this case planting conditions and agrotechnique play an important role. The aim of the research was to analyze the influence of a vegetation period duration of different sorts of sowing parsnip on formation of chemical composition components and roots preservation to determine the dependence between the content of dry soluble substances and one of dry substances, sugars, saccharose, reducing sugars, ascorbic acid. The research gives a possibility to get roots with the maximal content of chemical composition components and long storage period. There has been studied the influence of a vegetation period duration of different sorts of sowing parsnip on formation of chemical composition components and roots preservation. The dependence between the content of dry soluble substances and one of dry substances, sugars, saccharose, reducing sugars, ascorbic acid has been determined. The research has been conducted with parsnip roots of sowing sort Petrik, Student, Boris. There has been studied the influence of a ripeness degree (vegetation period duration) on a quality and preservation of parsnip roots. Parsnip roots of the sowing sorts Student and Boris are characterized by the most content of the dry substance 27,1–25,4 %, and content of the total sugar 5,7–5,4 %, high content of vitamin С 10,2–10,1 mg/100 g. It has been established, that the studied sorts are not inclined to nitrates accumulation, their content varies from 60 to 80 mg/kg and is lower than the maximally permitted level (MPL 250 mg/kg). There has been established the direct strong connection between the content of the dry substance and sugars content (r=0,98), nitrates content (r=0,80) and the middle content with the testing mark (r=–0,54) and vitamin С (r=0,57). The dry soluble substance content has the direct strong connection with the sugars content (r=0,99), nitrates content (r=0,78) and middle connection with the content of vitamin С (r=0,46) and reverse middle connection with the testing mark (r=–0,52). The reverse middle connection exists between the sugars content and the testing mark (r=–0,52) and the direct strong connection with nitrates content (r=0,84), middle connection with the content of vitamin C (r=0,48). At storage of roots the loss of the mass of dry substances is from 11,5 % at storage in an open box to 6,2 – in a polyethylene film. The most changes take place in saccharose and monosaccharides, 36,6 and 33,0 % respectively. The content of vitamin C decreases by 30 % at storage in an open box and by 10 % in a polyethylene film. The vegetation period duration as 150 days is characterized by the lower sugars content, but at that the ratio saccharose: monosacharides – the most. There has been offered the method of determining the ripeness degree of parsnip roots by the saccharose content. At the technical ripeness the amount of saccharose is 72–75 % of the total amount of sugars. The optimal ripeness is characterized by deceleration of growing processes, decrease of saccharose accumulation rates, the most ratio of the roots mass to the one of leaves and saccharose to monosugars. The method of roots storage with p. e. film decreases losses of nutrients of roots and increases the storage duration.