The aim of the study was to determine the effect of modified atmosphere (MA) packages on the external quality of organically grown lowbush blueberry and half-highbush blueberry (’Northblue’) and the nutritional value of the fruits. Fruits were divided into plastic punnets and stored as follows: regular atmosphere (RA), punnets without packing; punnets sealed in a low-density polyethylene (LDPE, Estiko) bag; punnets sealed in an Xtend^® blueberry bag (Stepac). Fruits were stored at 3 ± 1 °C. Compared to RA conditions, the Xtend^® package prolonged the postharvest life for 15 days for lowbush and 9 days for half-highbush blueberries. Fruit dry matter (DM) and titratable acidity (TA) were higher in the Xtend^® package. Fruit SSC decreased in the LDPE packages and increased in the Xtend^® packages during storage. Based on the decreased soluble solids content (SSC) and titratable acidity (TA) ratio (SSC:TA) values during storage, it can be concluded that the taste of the fruits became sourer in all packages. Anthocyanin biosynthesis of lowbush blueberries was suppressed in MA, but this effect was not noticed for ‘Northblue’. Regarding fruit firmness, shrivelling, and decay, there were significant differences between the MA packages, but the genetic differences were more important: half-highbush blueberry fruits were firmer and less shrivelled.

Vine growing and wine production is gaining in popularity around the Baltic Sea Region. The first aim of the experiment was to determine the variability of the total phenolic and anthocyanin content (from 2010 to 2018) and of individual anthocyanin content (from 2016 to 2018) in the hybrid grape cultivars ‘Hasansky Sladky’, ‘Zilga’, and ‘Rondo’. In field conditions ‘Rondo’ had winter cold damage to canes in two years. Therefore, the second aim was to determine the effect of high polyethylene tunnel and field conditions on fruit total and individual anthocyanin content of ‘Rondo’ from 2016 to 2018. Over nine years, the total phenolic content ranged from 192 to 671 mg 100 g⁻¹ and anthocyanins from 30 to 405 mg 100 g⁻¹ spectrophotometrically. The anthocyanin (delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside) content depended on cultivar properties and climatic parameters. Antioxidant activity was cultivar dependent and ranged from 40 to 88%. Polytunnel cultivation increased the content of total anthocyanins in ‘Rondo’ from 447 to 1472 mg 100 g⁻¹ (by chromatographically) in cooler year, but in warmer years it decreased from 3645 to 1618 mg 100 g⁻¹. Individual anthocyanins showed the same tendency. Grapevine cultivar ‘Rondo’ is recommended for tunnel growing in very cool climate conditions.

Revegetating abandoned peatlands plays an important role in reducing the CO₂ footprint. One possibility for carbon reduction is cultivating blueberries as calcifuge plants in acidic peat soil. The aim of the experiment was to find out the effect of different fertilizers on half-highbush blueberry cultivar ‘Northblue’ growth and biochemical parameters in peatland conditions. The experiment was carried out in 2011–2015 with four organic and one mineral fertilizer, where three were composted chicken manure- and one maltose-based organic fertilizer. The soil of the experimental area belongs to the soil subgroup Fibri–Dystric Histosol with the peat layer 1.0–1.5 m deep. Organic fertilizer 4–1–2, which contained seaweed but had low phosphorus and potassium content, resulted in high yields in 2011 and 2013, with similar vegetative growth and comparable biochemical parameters as mineral fertilizer 6–14–23. The principal component analysis showed that the experimental year was more important in determining fruit parameters than the fertilizer type. However, our results indicated that the organic fertilizers are alternatives to mineral fertilizer for organic production.

The objective of the study was to determine the effect of vintage and cultivar on the total polyphenol content and the antioxidant activity of wines made from the white wine cultivar ‘Solaris’ and the red wine cultivar ‘Zilga’ (both with skin maceration). The second goal was to describe the polyphenolic profile of ‘Solaris’ wine and compare it with that of ‘Zilga’ wine. Spectrophotometric methods were employed to determine the total polyphenol content and the antioxidant activity. High-performance liquid chromatography (HPLC) was used to determine the polyphenol composition. The total polyphenol content and the antioxidant activity of ‘Solaris’ wine differed significantly from that of ‘Zilga’ wine in the experimental years from 2021 to 2023. Significant differences between the wines also occurred on average over the years, with a significantly higher total polyphenol content and antioxidant activity obtained for the red wine of ‘Zilga’. However, both wines were similarly influenced by vintage over the three-year experimental period. The antioxidant activity showed a high correlation with the total polyphenol content. The polyphenolic profile of ‘Solaris’ wine differed notably from that of ‘Zilga’ wine. While ‘Solaris’ wine exhibited lower levels of phenolic acids and flavonols, the content of the flavanols was significantly higher, even double that of ‘Zilga’ wine. Among the flavanols, there was a remarkably high content of catechin and epicatechin.

This study compared polyethylene terephthalate (PET), corrugated cardboard (CB), cardboard with a cellulose lid (CBC), and rice-straw packages with a polylactic acid lid (RPLA) for half-highbush ‘Northblue’ and highbush ‘Draper’ blueberries. Fruits were stored for 7–8 days at 5 ± 1 °C and 40 ± 2% relative humidity to represent short local distribution conditions in Estonia. Packaging treatments influenced postharvest quality, and responses differed between the two cultivars. In ‘Northblue’, PET maintained lower weight loss (2.4%) and higher firmness (0.51 N) than CB (6.8% and 0.35 N), while CBC and RPLA showed intermediate weight loss and firmness. In ‘Draper’, CB resulted in the highest weight loss (10.6%) and a significant decline in total anthocyanin content from 90 to 49 mg 100 g⁻¹ FW, whereas RPLA showed the highest total phenolic content (207 vs. 144 mg 100 g⁻¹ FW in CB) and organic acid content (0.88 g 100 mL⁻¹). RPLA also maintained the highest organic acid content in ‘Northblue’ (0.65 g 100 mL⁻¹). RPLA showed potential for short-term storage under the low-RH conditions tested, although its performance differed between the two cultivars.