This study analysed fruits of cranberry cultivars: Ben Lear, Bergman, Early Richard, Pilgrim and Stevens and compared them with wild-grown cranberry fruits. The fruits were characterised in terms of dimensions, colour, content of total phenolic compounds, flavonoids, proanthocyanidins and anthocyanins, and hydroxyl radical and trypsin inhibition activities. It was shown that the wild-grown cranberry fruits were characterised by much smaller dimensions and redder colour than fruits of the cranberry cultivars. The most phenolic compounds were found in the Early Richard fruits (357.6 mg/100 g fw), and they showed the highest antitrypsin activity. The highest anthocyanin content (60.6 mg/100 g fw) was determined in the Pilgrim fruits, while the Ben Lear fruits were the richest source of proanthocyanidins (27.9 mg/100 g fw). The antioxidant activity was correlated with the content of phenolic compounds, flavonoids and proanthocyanidins, while the antitrypsin activity was correlated with phenolic compounds and anthocyanin contents.

The study assesses the antioxidant activity (AA), carotenoid profile and total phenolic content (TPC) of carrot juices obtained from three different varieties (black, orange and yellow) and prepared using high- (HSJ) and low-speed juicer (LSJ). The AA assessment was carried out using four assays (DPPH, ABTS, PCL ACW and PCL ACL). The content of carotenoids was conducted by high performance liquid chromatography equipped with a diode array detector (HPLC-DAD) method, while the total phenolic content by the spectrophotometric method. It was shown that orange carrot juices contain more carotenoids than yellow and black carrot juices, approximately ten and three times more, respectively. The total carotenoid content in orange carrot juice made by the HSJ was higher (by over 11%) compared to juice prepared by the LSJ. The highest total phenolic content was noticed in black carrot juices, while the lowest in orange carrot juices. In black carrot juices, a higher range of TPC was found in juices made by HSJ, while in the case of the orange and yellow carrots, the highest content of TPC was detected in juices prepared by the LSJ. AA of the juices was highly dependent on the carrot variety, juice extraction method. The most assays confirmed the highest AA values in black carrot juices. Furthermore, it was shown that the HSJ method is more preferred to obtain orange and yellow carrot juices with higher antioxidant properties, while the LSJ method is more suitable for black carrot juice extraction.

The study examined the effects of various methods of thermal treatment of Lord cultivar potato tubers on changes in starch, polyphenols, vitamin C, antioxidant activity, and mineral compounds. Following heat treatment in order to determine further transformations of starch, the potatoes were stored at 2 °C/24 h. Changes in starch, bioactive compounds and antioxidant properties varied depending on the treatment method. In general, higher retention of bioactive compounds was noted for tubers treated with “dry” methods, such as microwaving or grilling than for tubers treated with “wet” methods, e.g., boiling in water, steam cooking or cooking in a combi oven. These samples were also characterised by a higher resistant starch content. Cold storage resulted in an increase in the proportion of resistant starch. Total phenols content ranged from 210.96 (boiling) to 348.46 mg/100 g DW (grilling) and vitamin C content ranged from 43.79 (boiling) to 68.83 mg/100 g DW (microwaving). DPPH radical scavenging activity was the highest for the grilled tubers. The results indicate microwaving and grilling as the most favourable thermal treatments of potato.