A Comparative Study of Ten Pear (Pyrus communis L.) Cultivars in Relation to the Content of Sugars, Organic Acids, and Polyphenol Compounds.

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', 'Budaljaca', and 'Krakaca' 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 'Takisa' and 'Ahmetova'. High polyphenol content detected in 'Budaljaca', 'Dolokrahan', and 'Krakaca' 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.

Distribution and Stability of Polyphenols in Juices Made from Traditional Apple Cultivars Grown in Bosnia and Herzegovina.

The present research was undertaken to investigate polyphenolic profiles of peel, pulp and juices made from two standard commercial and five traditional apple cultivars from Bosnia and Herzegovina. The main goal of the study was to monitor the distribution and changes of polyphenolic profiles through different phases of apples' processing into cloudy and clear juices, with regard to L-ascorbic acid pretreatment. Quantitative determination of phenolic compounds was carried out by using high-performance liquid chromatography with diode-array detection. The obtained results showed that traditional cultivars, namely 'Paradija' and 'Prijedorska zelenika', displayed significantly higher content of these compounds compared to commercial ones. Flavan 3-ols and flavonol glycosides were mostly found in peels of all cultivars (21.2-44.1 and 5.40-33.3%, respectively), while phenolic acids along with flavan 3-ols were predominant in the pulp (8.20-30.8 and 5.10-13.9%, respectively). Apples' processing into juices caused decrease (more than 90%) in the content of all polyphenols and the distribution of these compounds from fruits to final products had a negative trend, particularly evident in clear juices. The most drastic loss occurred in the flavonol glycosides and dihydrochalcones content, while chlorogenic acid displayed quite stable distribution from apples to final products due to its good solubility. Apple mash pretreatment with L-ascorbic acid had a positive impact on the preservation and retention of polyphenols.

Geographic Variability of Sugars and Organic Acids in Selected Wild Fruit Species.

The chemical variability of bilberry (Vaccinium myrtillus L.), wild strawberry (Fragaria vesca L.), cornelian cherry (Cornus mas L.) and rosehip (Rosa canina L.) based on the content of individual and total sugars and organic acids in fruit was investigated. The fruits were picked in fully ripened condition within the period from 2014 to 2015 from different locations. The fresh fruits were analyzed with the high performance liquid chromatography (HPLC) technique for the purpose of identifying and quantifying the content of glucose, fructose and sucrose, as well as malic, citric, fumaric and shikimic acids. However, the content of individual sugars and organic acids differed by locations as well as by growing year within the same wild fruit species. The differences between wild fruit species as well as among different locations are presented by principal component analysis (PCA). Based on results obtained, rosehip fruits with higher sugars and organic acids ratio (S/A) are suitable for production of "pekmez" and drying, while genotypes of cornelian cherry, wild strawberry and bilberry with lower S/A are recommended for production of juices and gelatin products. The research results show that specific environmental conditions may influence significantly the content of analyzed parameters, as is the case with cornelian cherry and rosehip. Considering that the food industry is searching for new products, the wild fruit species analyzed represent a promising source of ingredients for the development of beverages and foods with functional properties as well as for supplements and nutraceuticals.