Effect of different organic farming methods on the phenolic composition of sea buckthorn berries

The effects of different organic cultivation methods on the berry phenolics of two Finnish sea buckthorn (Hippophae rhamnoides L. ssp. rhamnoides ) cultivars, 'Terhi' and 'Tytti', were studied in an experimental field at a coastal area in Merikarvia, western Finland. Cultivation methods included different fertilizers (designed for organic cultivation), mulches (organic and plastic), and land contours (flat land versus ridged beds). Two experiments were conducted: The first, a fertilization experiment, allowed for the estimation of the effects of cultivar, fertilizer, land contour, and all of their interactions. The second experiment, a mulch experiment, allowed for the estimation of the effects of mulch, land contours, and their interactions for the cultivar 'Tytti'. Berry phenolics were analyzed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. The results suggest that there are significant differences between the cultivars and cultivation methods. The concentrations of quercetin derivatives 1-3, isorhamnetin 3,7-diglucoside, quercetin-3-glucoside-7-rhamnoside, quercetin 3-glucoside, isorhamnetin 3-glucoside, and flavonoid derivative 3 were higher in 'Tytti' than in 'Terhi', while concentrations of isorhamnetin-glucoside 2 and 3 were higher in 'Terhi' than in 'Tytti'. Flat land increased the concentrations of isorhamnetin 3,7-diglucoside, isorhamnetin-glucoside 1, quercetin derivatives 2 and 4, and condensed tannins. Mulch did not have any significant effect on the concentrations of phenolic compounds. These results indicate that the phenolic accumulation in berries of studied sea buckthorn cultivars seems to be mainly dependent upon cultivar selection and soil structure.