Sea Buckthorn Leaf Powders: The Impact of Cultivar and Drying Mode on Antioxidant, Phytochemical, and Chromatic Profile of Valuable Resource.

Sea buckthorn (Hippophae rhamnoides L. (HR)) leaf powders are the underutilized, promising resource of valuable compounds. Genotype and processing methods are key factors in the preparation of homogenous, stable, and quantified ingredients. The aim of this study was to evaluate the phenolic, triterpenic, antioxidant profiles, carotenoid and chlorophyll content, and chromatic characteristics of convection-dried and freeze-dried HR leaf powders obtained from ten different female cultivars, namely 'Avgustinka', 'Botaniceskaja Liubitelskaja', 'Botaniceskaja', 'Hibrid Percika', 'Julia', 'Nivelena', 'Otradnaja', 'Podarok Sadu', 'Trofimovskaja', and 'Vorobjovskaja'. The chromatic characteristics were determined using the CIELAB scale. The phytochemical profiles were determined using HPLC-PDA (high performance liquid chromatography with photodiode array detector) analysis; spectrophotometric assays and antioxidant activities were investigated using ABTS (2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and FRAP (ferric ion reducing antioxidant power) assays. The sea buckthorn leaf powders had a yellowish-green appearance. The drying mode had a significant impact on the total antioxidant activity, chlorophyll content, and chromatic characteristics of the samples; the freeze-dried samples were superior in antioxidant activity, chlorophyll, carotenoid content, and chromatic profile, compared to convection-dried leaf powder samples. The determined triterpenic and phenolic profiles strongly depend on the cultivar, and the drying technique had no impact on qualitative and quantitative composition. Catechin, epigallocatechin, procyanidin B3, ursolic acid, α-amyrin, and ß-sitosterol could be used as quantitative markers in the phenolic and triterpenic profiles. The cultivars 'Avgustinka', 'Nivelena', and 'Botaniceskaja' were superior to other tested cultivars, with the phytochemical composition and antioxidant activity.

Variability in the Qualitative and Quantitative Composition of Phenolic Compounds and the In Vitro Antioxidant Activity of Sour Cherry (Prunus cerasus L.) Leaves.

Sour cherry (Prunus cerasus L.) is a deciduous tree belonging to the Rosaceae Juss. family. Cherry leaves are an underutilized source of biologically active compounds. The aim of this study was to determine the composition of the phenolic compounds, as well as the total antioxidant activity, in leaf samples of P. cerasus cultivars and to elucidate the cultivars with particular phytochemical compositions. The phytochemical profiles of P. cerasus leaves vary significantly in a cultivar-dependent manner. The total content of identified phenolic compounds varied from 8.254 to 16.199 mg/g in the cherry leaves. Chlorogenic acid ranged between 1413.3 µg/g ('North Star') and 8028.0 µg/g ('Note'). The total content of flavonols varied from 4172.5 µg/g ('Vytenu zvaigzde') to 9030.7 µg/g ('Tikhonovskaya'). The total content of identified proanthocyanidins varied from 122.3 µg/g ('Note') to 684.8 µg/g ('Kelleris'). The highest levels of phloridzin (38.1 ± 0.9 µg/g) were found in samples of 'Molodezhnaya', while the lowest level of this compound was determined in the leaf samples of 'Turgenevka' (6.7 ± 0.2). The strongest antiradical (138.0 ± 4.0 µmol TE/g, p < 0.05) and reducing (364.9 ± 10.5 µmol TE/g, p < 0.05) activity in vitro was exhibited by the cultivar 'Vytenu zvaigzde' cherry leaf sample extracts. 'Kelleris', 'Note', and 'Tikhonovskaya' distinguish themselves with peculiar phytochemical compositions.

Performance of Sweet Cherry Cultivars and Advanced Selections on Gisela 5 Rootstock in Young Orchards.

Six sweet cherry cultivars and two advanced selections of Gisela 5 rootstock were tested in 2015-2021 at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry. Fruit trees were planted at distances of 4.5 × 2.5 m and trained as spindles. Orchard floor management included frequently mown grass in alleyways with herbicide strips along tree rows. Cultivars 'Mindauge' and 'Irema BS' were the most vigorous at the end of the seventh leaf. Their trunk diameter achieved 11.6 cm. The 'Merchant' cultivar had the smallest trunk diameter-9.3 cm. The average yield in 2018-2021 ranged from 2.75 t/ha for 'Vega' to 8.73 t/ha for 'Regina'. Cultivars 'Regina', 'Sunburst', 'Irema BS' and 'Merchant' had the highest cumulative yield efficiency of 0.440-0.503 kg/cm2 with respect to the trunk cross-section area (TCSA). The least productive cultivar 'Vega' produced fruits of the highest average weight-9.9 g. Fruits of 'Regina' and 'Sunburst' were large as well-8.8-9.1 g. 'Irema BS' fruits had the highest soluble solids content (SSC)-20.2%. The lowest SSC was recorded in 'Merchant' and 'Sunburst' fruits-14.7-15.8%. The yield of advanced selection, No. 102, equaled to the yield of cv. 'Regina'. No. 102 had a high fruit weight, and fruits were distinguished by attractiveness and taste.

Apple Fruit Growth and Quality Depend on the Position in Tree Canopy.

Modern apple orchard systems should guarantee homogeneity of fruit internal and external qualities and fruit maturity parameters. However, when orchards reach productive age, a variation of these parameters takes place and mostly it is related to uneven light distribution within the tree canopy. The aim of the study was to evaluate the canopy position's effect on fruit internal and external quality parameters. This is the first study where all the main fruit quality and maturation parameters were evaluated on the same trees and were related to the light conditions and photosynthetic parameters. Four fruit positions were tested: top of the apple tree, lower inside part of the canopy, and east and west sides of the apple tree. Fruit quality variability was significant for fruit size, blush, colour indices, total sugar content, dry matter concentration, accumulation of secondary metabolites and radical scavenging activity. Fruit position in the canopy did not affect flesh firmness and fruit maturity parameters such as the starch index, Streif index and respiration rate. At the Lithuanian geographical location (55°60' N), significantly, the highest fruit quality was achieved at the top of the apple tree. The tendency was established that apple fruits from the west side of the canopy have better fruit quality than from the east side and it could be related to better light conditions at the west side of the tree. Inside the canopy, fruits were distinguished only by the higher accumulation of triterpenic compounds and higher content of malic acid. Light is a main factor of fruit quality variation, thus all orchard management practices, including narrow two-dimensional tree canopies and reflecting ground covers which improve light penetration through the tree canopy, should be applied.

Variability in the Content of Phenolic Compounds in Plum Fruit.

The aim of this study was to determine the composition and content of phenolic compounds in extracts of plum fruit. Fruit of 17 plum cultivars were analyzed. Fruit samples were collected in 2019 from fruit trees with "Myrobalan" (P. cerasifera Ehrh.) and "Wangenheim Prune" (P. domestica L.) rootstocks. The following glycosides of the flavonol group were identified: avicularin, isorhamnetin-3-O-rutinoside, isoquercitrin, hyperoside, rutin, and an aglycone quercetin. Compounds of the flavan-3-ol group were identified, such as (+)-catechin, procyanidin C1, and procyanidin A2, along with chlorogenic acid attributed to phenolic acids and a non-phenolic cyclitol-quinic acid. Of all the analytes identified in plum fruit samples, quinic acid predominated, while chlorogenic acid predominated among all the identified phenolic compounds, and rutin predominated in the flavonol group. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) revealed that fruit samples of "Kubanskaya Kometa", "Zarechnaya Raniaya", "Duke of Edinburgh", "Jubileum", and "Favorita del Sultano" cultivars had different quantitative content of phenolic compounds from that observed in other samples. The highest total amount of phenolic compounds was found in the European plum samples of the "Zarechnaya Rannyaya" cultivar, while the amount of quinic acid was the highest in plum fruit samples of the "Jubileum" cultivar.