Martina Skendrović Babojelić

Influences of organically and conventionally grown strawberry cultivars on anthocyanins content and color in purees and low-sugar jams.

The objective of this study was to detect influences of cultivar, cultivation and processing on anthocyanin content and color in purees and low-sugar jams produced from strawberry cultivars (Elsanta, Maya, Marmolada, Queen Elisa), grown under conventional and organic cultivation. Color was determined by CIELab values while anthocyanins were quantified by HPLC-UV/VIS-PDA. Queen Elisa was the best cultivar for processing as it had highest total anthocyanin content (TAC) that was well preserved in processing. On average, processing purees to jams decreased TAC for 28% where pelargonidin-3-glucoside revealed most noticeable loss (53%) and cyanidin-3-rutinoside was best preserved in processing. Obtained results indicated that measurement of colorimetric parameters are strongly correlated with content of anthocyanins. In other words, loss of anthocyanins during processing was accompanied by noticeable decrease in lightness, red/yellow color and total color change. Results showed that change of color is useful predictor for estimating anthocyanins in strawberry purees and jams.

The change of fruit quality parameters in day-neutral strawberries cv. Diamante grown out of season

This research was conducted on the strawberry cultivar Diamante in continental parts of Croatia. The experiment was designed as four replicates with 100 plants for each harvest time. The quality of strawberries cv. Diamante grown out of season (fruit were picked in the early morning hours at three harvest times: 27 June, 7 September, 28 October) was determined. Total soluble solids (°Brix) ranged from 5.00% to 7.03%, total acidity ranged from 1.05% to 1.12%, total soluble solids/acidity ranged from 4.74 to 6.34, vitamin C ranged from 40.73 mg/100 g fresh weight to 46.68 mg/100 g fresh weight, pH ranged from 3.53 to 3.72, total phenols ranged from 276.48 to 326.76 mg/l, non-flavonoids ranged from 169.50 to 260.53 mg/l, and flavonoids ranged from 44.71 to 106.53 mg/l, respectively. In addition, total anthocyanins ranged from 15.95 to 21.70 mg/l. The lightness L values of fruits ranged from 30.24 to 41.05, chroma C values from 25.92 to 34.13, and Hue angle H values from 44.51 to 56.02. The data showed that cv. Diamante grown out of season is of satisfactory quality.

Differential accumulation of photosynthetic proteins regulates diurnal photochemical adjustments of PSII in common fig (Ficus carica L.) leaves

Molecular processes involved in photosystem II adaptation of woody species to diurnal changes in light and temperature conditions are still not well understood. Regarding this, here we investigated differences between young and mature leaves of common fig (Ficus carica L.) in photosynthetic performance as well as accumulation of the main photosynthetic proteins: light harvesting complex II, D1 protein and Rubisco large subunit. Investigated leaf types revealed different adjustment mechanisms to keep effective photosynthesis. Rather stable diurnal accumulation of light harvesting complex II in mature leaves enabled efficient excitation energy utilization (negative L-band) what triggered faster D1 protein degradation at high light. However, after photoinhibition, greater accumulation of D1 during the night enabled them faster recovery. So, the most photosynthetic parameters, as the maximum quantum yield for primary photochemistry, electron transport and overall photosynthetic efficiency in mature leaves successfully restored to their initial values at 1a.m. Reduced connectivity of light harvesting complexes II to its reaction centers (positive L-band) in young leaves increased dissipation of excess light causing less pressure to D1 and its slower degradation. Decreased electron transport in young leaves, due to reduced transfer beyond primary acceptor QA- most probably additionally induced degradation of Rubisco large subunit what consequently led to the stronger decrease of overall photosynthetic efficiency in young leaves at noon.