Black fruits, especially blackberries and black currants, are highly appreciated by consumers due to their nutraceutical properties, which have reported health benefits. This study aimed to assess the fruit quality of the blackberry (cv. ‘Čačanska Bestrna’) and black currant (cv. ‘Čačanska Crna’) created at the Fruit Research Institute, Čačak (Republic of Serbia) by evaluating basic quality parameters (fruit weight, soluble solids), and content of primary (sugars and organic acids) and secondary (phenolic compounds) metabolites. Additionally, the study examined the quality of frozen and long-term frozen storage (6, 9, and 12 months). The results showed that ‘Čačanska Crna’ contained a high level of total soluble solids (15.23°Bx), sugars (93.06 mg g⁻¹), and a high index of sweetness (159.48) as well as a high content of acids (34.35 mg g⁻¹) in the fruit. Both species were found to contain forty-seven phenolic compounds, including phenolic acids, flavanols, and anthocyanins, analyzed using high performance liquid chromatography-mass spectrometry (HPLC-MS). ‘Čačanska Bestrna’ had the highest amounts of phenolic acids (66.85 mg 100 g⁻¹) and flavanols (53.99 mg 100 g⁻¹), whereas ‘Čačanska Crna’ showed the highest levels of flavonols (8.57 mg 100 g⁻¹) and anthocyanins (139.11 mg 100 g⁻¹). Furthermore, the study revealed that anthocyanins were the most abundant phenolic group in both blackberries and black currants, and their levels remained constant during frozen storage. The sugar content in both species remained unchanged, while the acid concentration increased over time in blackberries but remained consistent in black currants. Overall, the findings highlight the superior phenolic content, particularly anthocyanins, of the cultivars with black fruits selected in Serbia. These cultivars have great commercial potential for the fresh market and processing. Moreover, the study suggests that frozen storage is an effective method for preserving their quality and beneficial properties.

We analyzed the red-fleshed apple cultivar ‘Baya Marisa’ and compared it with the traditional, white-fleshed apple cultivar ‘Golden Delicious’. The objective of this study was to compare sugars, organic acids, and phenolic compounds of ‘Baya Marisa’ with the widely known and consumed white-fleshed apple cultivar ‘Golden Delicious’. In addition, flesh firmness, color, and soluble solid content was studied. A total of 46 phenolic compounds were quantified and identified, some for the first time in apples. The study showed that the total analyzed phenolic content (TAPC) was 1.6× higher in the skin of red-fleshed ‘Baya Marisa’ and 1.4× higher in the flesh of red-fleshed ‘Baya Marisa’. Organic acid (citric acid, malic acid, and ascorbic acid) content was higher in the red-fleshed cultivar ‘Baya Marisa’, whereas sugar content (sucrose, glucose, and sorbitol) was similar, except for fructose, which was 1.1× higher in ‘Golden Delicious’. The content of citric acid was 1.6× higher in ‘Baya Marisa’, whereas the content of malic acid was 1.2× higher in ‘Baya Marisa’ and the content of ascorbic acid was 2.8× higher in ‘Baya Marisa’. Among phenolics, total dihydrochalcones in the skin were 3.3× higher in ‘Baya Marisa’ and similar in the flesh compared to ‘Golden Delicious’. Flavonols were 1.4× higher in the skin of ‘Baya Marisa’ and 2.8× higher in the flesh of ‘Golden Delicious’. Anthocyanins were not identified in the white-fleshed cultivar ‘Golden Delicious’. Total hydroxycinnamic acids were 2.0× higher in the skin of ‘Golden Delicious’ and similar in the flesh compared to ‘Baya Marisa’. Total flavanols were 1.8× higher in the skin and 2.2× higher in the flesh of the white-fleshed cultivar ‘Golden Delicious’.

The brown marmorated stink bug (BMSB; Halyomorpha halys Stal.) has become a significant pest in Slovenia, especially in apple, pear, peach, and cherry orchards. In our study, apple fruit of the apple cultivar ‘Red Pinova’ were evaluated for visual injury and sugar, organic acid, and phenolic contents. The chemical composition of the area around the puncture wound, the uninjured part of the infested apple, was compared to, as a control, only uninjured apples. There was a significant response of the apple around the puncture wound, resulting in an 11.9 g/kg FW higher total sugar content, a 1.4 g/kg FW lower total organic acid content, and an 11.9 g/kg FW higher total phenolic content compared with control apples. A strong phenolic response in the puncture wound area, with high flavanol and hydroxycinnamic acid contents, with increases of 118% and 237%, respectively, compared with control apples, was detected. The brown marmorated stink bug induces a strong phenolic response in the injured area of the apple. The results of this study illustrated how apple fruit responds to the BMSB injury, not only sensorily (visual injury, odor), but also chemically in the form of metabolic responses.