Traditional pear cultivars are increasingly in demand by consumers because of their excellent taste, the possibility of use in sustainable food production systems, convenience as raw materials for obtaining products of high nutritional quality, and perceived health benefits. In this study, individual sugars, organic acids, and polyphenols in the fruits of nine traditional and one commercial pear cultivar during two growing seasons were determined by HPLC. A significant influence of cultivars, growing years, and their interaction on the content of analyzed primary and secondary metabolites was determined. The commercial pear cultivar ‘Président Drouard’ and traditional cultivars ‘Dolokrahan’, ‘Budaljača’, and ‘Krakača’ had a lower content of all analyzed sugars. Overall, traditional pear cultivars had higher total polyphenols in the peel and pulp than ‘Président Drouard’, with the exception ‘Takiša’ and ‘Ahmetova’. High polyphenol content detected in ‘Budaljača’, ‘Dolokrahan’, and ‘Krakača’ shows the utilization value of traditional pear germplasm. The obtained data can serve as practical supporting data for the use of traditional pears in the neutraceutical, pharmaceutical, and food industries.

Pozegaca’ is the most important native plum genotype in southeast Europe. In this study, the phytochemical fruit composition of the ‘Pozegaca’ ecotype from four different growing regions was evaluated over three growing years. HPLC was used for identification and quantification of sugars, organic acids and phenolic compounds in the fruits. The total effects of growing years and regions on different phytochemical characteristics of ‘Pozegaca’ fruit were analysed using principal component analysis (PCA). Glucose, fructose, sucrose and sorbitol were detected as major sugars in ‘Pozegaca’ fruit. Malic, citric, fumaric and shikimic acids were identified in the studied plum ecotype. Glucose was the predominant sugar and malic acid was the predominant organic acid. A range of phenol compounds was identified, including hydroxycinnamic acids, flavonols, anthocyanins and flavan3-ols. The main factor affecting the fruit quality and phenol composition of the ‘Pozegaca’ plum ecotype in skin and pulp was the growing year. The geographical origin of the ‘Pozegaca’ ecotype appears to have no major influence on the phenol profile of ‘Pozegaca’ fruit. The results showed that air temperature has a strong correlation with sugar compounds (particularly with fructose and sucrose) and with some organic acids (fumaric, shikimic and citric). Related to the accumulation of phenol compounds, air temperature strongly correlated with flavanols (particularly with quercetin 3-rutinoside) and anthocyanins in pulp. Precipitation and altitude were strongly correlated with total phenols in pulp, chlorogenic acid in skin and pulp, neochlorogenic acid in pulp, and all three identified flavanols in pulp. The results showed that specific seasonal and geographic environmental conditions could significantly affect the content of secondary metabolites in ‘Pozegaca’ fruit.

Three commercial apple cultivars ('Jonagold', 'Granny Smith' and 'Idared') and the local apple cultivar ('Prijedorska Zelenika') from Bosnia and Herzegovina were analysed by HPLC-MS for the content of phenolic compounds in peel and pulp as well content of individual sugars and organic acids. Catechin, (-)-epicatechin, chlorogenic acid, caffeic acid, quercetin 3-O-xyloside, quercetin 3-O-arabinoside, quercetin 3-O-rhamnoside, quercetin 3-O-rutinoside, quercetin 3-O-galactoside and quercetin 3-O-glucoside were identified in apple peel and (-)-epicatechin, chlorogenic acid and caffeic acid in apple pulp at all observed cultivars. The total sugars content of analysed apple cultivars ranged between 91.61 and 105.45 g kg-1 FM, while the total organic acids content was from 5.70 to 15.05 g kg-1 FM. The levels of total organic acids and sugars, glucoce/fructose ratio and sugar/acid ratio were affected by cultivars. The mean content of total phenolic compounds was between 427.92 and 1457.95 mg kg-1 FM in peel and from 113.58 to 439.83 mg kg-1 FM in pulp and depending upon the cultivars. The presented data clearly demonstrated that traditional apple cultivar ('Prijedorska Zelenika') had significantly higher individual phenolic compounds in pulp in comparison to the commercial cultivars, i.e., 'Idared', 'Jonagold' and 'Granny Smith' and with respect of that 'Prijedorska Zelenika' is recommended as raw material for cloudy juice processing.

The main purpose of this study was to evaluate the effect of calcium fertilizer treatments on fruit quality and distribution of calcium in apple fruit (Malus domestica Borkh. cv. Idared). Four treatments were tested: application of calcium nitrate through the fertigation system, foliar application of calcium nitrate, application of calcium oxide through soil, and control treatment (without calcium fertilizer). In the experiment, freshly picked apples harvested in Gorazde region (eastern Bosnia) in September 2018 were analyzed. The highest impact to increase calcium content in apple had a treatment where calcium nitrate was added through the fertigation system. It was the result of the balance between calcium and nitrogen in the applied solution as well as the fertigation capacity to timely deliver nutrition to the main rooting zone. Calcium distribution was not uniform within the fruit: the highest content was found in the apple core, decreasing in the apple flesh, and rising again in the apple skin, regardless of fertilizer treatment. There was no difference among calcium fertilizer treatments in total soluble solids and titratable acidity of apple, indicating that these treatments were insufficient in order to improve the examined parameters of fruit quality.