Polyphenols content in rosehips Rosa Rugosa Thunb. and Rosa Canina L. dependence on the ripening stage

Abstract

Different harvesting time can largely influence the content of bioactive compounds in different variety rosehips. The field experiment was carried out in an organic farm in Pakruojis district, Lithuania. The aim of this study was to determine the effect of ripening stage on polyphenol content of two different rosehip flesh species R. rugosa and R. canina. The fruits were harvested five times in season. The first stage (H-1) was performed when the fruit color changed slightly from green to yellow, pink or red no less than 10% of the surface. The second stage (H-2) was performed when the fruit color changed from green to tarnish – yellow, pink or red no less than 30% of the surface. The third stage (H-3) was performed when the fruit color changed from green to light orange or red or a combination thereof no less than 60% of the surface. The fourth stage (H-4) was performed when the fruit became pinkish or orange depending on the species. The fifth stage (H-5) was performed when the fruit surface was red. Polyphenols were determined using HPLC system by the method described by Hallmann (2012). The results demonstrated that the significantly highest contents of total flavonoids were identified in the R. rugosa species and the highest amount was in fully ripe fruits (H-5) (18.73 mg g-1 DW). The total polyphenols and total phenolic acids contents in fruits of R. canina were significantly higher than in the fruits of R. rugosa and the highest concentration were determined at fifth harvesting stage (H-5) (respectively 70.90 and 59.60 mg g-1 DW). Total polyphenols, total flavonoids and total phenolic acids content showed that the main factor determining the differences in accumulation of biologically active compounds is the species of rosehips and ripening stage.