Ramunė Bobinaitė

Improving the Extraction of Juice and Anthocyanin Compounds from Blueberry Fruits and Their by-Products by Pulsed Electric Fields

The aim of the study was to investigate the influence of PEF pre-treatment (1, 3, 5 kV/cm and 10 kJ/kg) of blueberry fruits on the extraction yield, anthocyanins content and antioxidant activity of the juice obtained by pressing (1.32 bar for 8 min). Additionally, the extraction with solvent of anthocyanins from the berry by-products (pressed cakes) was also evaluated. Blueberry juice obtained from PEF treated berries at 1 and 3 kV/cm showed the highest increase in juice yield (+32%), total anthocyanins content (+55%) and DPPH-RSC (+ 40%), compared with the untreated sample. The extracts from press cakes obtained after PEF assisted-pressing of berry fruits showed a significant higher content of total anthocyanins (+95%) and DPPH-RSC (+138%) when compared with the control sample. The higher the field strength applied the greater the recovery of antioxidant compound in the extracts. Significant differences in the contents of anthocyanin glycosides were detected between blueberry juice and press cake extracts. The results obtained from this study demonstrate that PEF-assisted pressing is promising for production of higher quality juices and for the valorization of berry by-products.

Chemical Composition of Raspberry ( Rubus spp.) Cultivars

Abstract Raspberries are among the most popular berries in the world. They are consumed as fresh fruits and processed into various products. There are over 250 heterozygous species within the Rubus genera; however, nowadays European red raspberry (Rubus idaeus L. subsp. idaeus), the North American red raspberry (R. idaeus subsp. strigosus Michx.)), and the black raspberry (Rubus occidentalis L.) are the most important commercial products. Raspberries are rich in vitamins C, A, B, B1, B2, PP, E, folic acid, phytochemicals anthocyanins, ellagitannins, and mineral elements iron and potassium, and therefore, they are recommended by dieticians as a healthy food. Numerous genotypes of raspberries have been developed in different countries seeking to obtain commercial cultivars with increased productivity, higher content of valuable nutrients, stronger antioxidant potential, and other valuable characteristics. This chapter reviews the studies reporting the composition of raspberry cultivars developed and grown in different countries all over the world.

CHARACTERISATION OF TOMATO JUICE AND DIFFERENT TOMATO-BASED JUICE BLENDS FORTIFIED WITH ISOMERISED LYCOPENE EXTRACT

Juices and beverages with bioactive compounds are consumed for their nutritive and health benefits. Beverages fortified with various functional ingredients are an important product category within the functional food segment. In this study tomato juice with various proportions of apple, carrot and sweet corn juice together with isomerised lycopene extract were used for formulation of functional beverages. Chemical composition and physicochemical properties of prepared juice blends was evaluated and a sensory analysis was conducted in order to identify the most acceptable blends. The addition of concentrated isomerised lycopene extract with beta-carotene to tomato juice as well as juice blends significantly increased the levels of lycopene and especially the levels of cis -lycopene in the final products. The content of total lycopene in the juice blends varied from 16.21 mg/100 g to 25.65 mg/100 g, whereas the content of cis -lycopene – from 9.16 to 14.46 mg/100 g. The juice blends containing apple juice had the lowest pH and the highest titratable acidity. Higher percentage of apple, sweet corn or carrot juice in the blends resulted in higher contents of TSS in the functional beverage. The addition of apple, carrot, and sweet corn juice significantly changed the initial color of the tomato juice. The lowest colour difference (E) values had tomato-carrot juice blends (6.8–7.3), whereas the highest E had tomato juice with 25 and 35 % of sweet corn juice (10.6 and 14.3, respectively). Sensory evaluation revealed that the most acceptable taste had tomato-apple juice blend with 35 % apple juice and tomato-carrot juice blend with 40 % carrot juice. Keywords: functional foods, juice blends, lycopene extract, sensory properties, tomato. Article DOI: http://doi.org/10.15544/RD.2015.029

OPTIMAL POSTHARVEST STORAGE PARAMETERS AND SHELF LIFE OF BABY SPINACH (SPINACIA OLERACEA L.)

This work was done to evaluate the optimal postharvest storage parameters and shelf life of baby spinach. Baby spinach (50 g) was sealed in three different polypropylene (PP) and polyethylene (PE) packaging materials: 30 m (PP), 35 m (PE) & 40 m (PE), and were stored in darkness for 3 and 9 days at 0 °C, 4 °C, 8 °C & 16 °C ( 1 °C). Total content of phenolics, soluble solids, nitrates, chlorophyll content, ascorbic acid & spinach color (CIEL*a*b*) were measured by standard methods after 3 and 9 days of storage. Baby spinach stored at 0 ± 1 °C and 4  1 °C showed the best visual quality. Storage temperature had significant influence on spinach colour, but the influence of packaging was not so strong. The content of soluble solids, ascorbic acid and nitrates decreased during storage. The highest amount of ascorbic acid was retained when baby spinach were stored in 40 m PE bags at 0 ± 1 °C. When baby spinach was stored at higher temperatures (4 °C, 8 °C & 16 °C), the decrease in the amount of ascorbic acid ranged from 55 % to 69 %. Baby spinach stored for 9 days at 0 °C & 4 °C showed high visual and biochemical quality. Higher amounts of soluble solids and ascorbic acid were found in spinach stored in 40 m PE bags. Keywords: postharvest storage, spinach, Spinacia oleracea L. Article DOI: http://doi.org/10.15544/RD.2015.024

Agronomical Characters of Introduced New Blackcurrant Cultivars

The blackcurrant cultivars ‘Abanos’, ‘Ronix’, ‘Deea’, ‘Geo’ (Romania), ‘Almo’ (Estonia), ‘Narve Viking’, ‘Varde Viking’ (Norway), ‘Mikael’ (Finland), and standard cultivar ‘Ben Tirran’ (Scotland) were tested at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2009-2012. Two-year-old bushes were planted in an orchard in 2009. Bush parameters (vigour and width, m), resistance to anthracnose (Pseudopeziza ribis) and leaf spot (Septoria ribis), berry weight (weight of 100 fruits), yield (kg/bush) and biochemical composition were determined. The study showed that ‘Geo’ was most resistant to fungal disease. Fruits of ‘Abanos’ and ‘Almo’ were the largest. Yield of cultivars ‘Ronix’, ‘Ben Tirran’ and ‘Deea’ were the highest. ‘Abanos’ and ‘Geo’ had the highest content of soluble solids, ‘Ben Tirran’ of titratable acid, ‘Varde Viking’ of anthocyanins and phenols, and ‘Ronix’ and ‘Narve Viking’of ascorbic acid. Upeņu šķirņu pētījumi veikti Lietuvas Lauksaimniecības un Meža pētījumu centra Dārzkopības institūtā laikā no 2009 līdz 2012. gadam. Pētījumos iekļautas šķirnes ‘Abanos’, ‘Ronix’, ‘Deea\ ‘Geo’ (Rumānija), ‘Almo’ (Igaunija), ‘Narve Viking’, ‘Varde Viking’ (Norvēģija), ‘Mikael’ (Somija). Stādījums ierīkots 2009. gadā, izmantojot divgadīgus stādus. Pētīti krūmu parametri (augstums, platums, m) izturība pret ogulāju iedegām (Pseudopeziza ribis) un ogulāju sīkplankumainību (Septoria ribis), svērta ogu masa (100 ogu masa, g ), raža (kg/krūma) un analizēts bioķīmiskais saturs. Pētījumu rezultāti rāda, ka izturīgākā pret sēņu slimībām bija šķirne ‘Geo’. Lielākās ogas bija šķirnēm ‘Abanos’ un ‘Almo’. Augstākā ražība bija šķirnēm ‘Ronix’, ‘Ben Tirran’ un ‘Deea’, bet šķirnēm ‘Abanos’ and ‘Geo’ ogās bija augstākais šķīstošās sausnas saturs. Šķirnes ‘Ben Tirran’ ogas saturēja visvairāk titrējamās skābes , ‘Varde Viking’ antocianīnu un fenolu , ‘Ronix’ un ‘Narve Viking’ - askorbīnskābi.