Darko Velić

Effect of extraction conditions on the extractability of phenolic compounds from lyophilised fig fruits (Ficus carica L.).

Effect of Extraction Conditions on the Extractability of Phenolic Compounds from Lyophilised Fig Fruits (Ficus Carica L.) In this work the influence of 50-80% (v/v) aqueous ethanol and the temperature of extraction (25-80°C) on the extractability of total phenolics, total flavonoids and total proanthocyanidins from different fig fruits was investigated. The best extraction conditions (80%, v/v aqueous ethanol, 80°C) obtained in the experiments with lyophilised Ficus carica L. cv. Šaraguja were used while performing the extraction of phenolic compounds from other fig varieties (Bružetka bijela, Crnica, Bjelica and Termenjača). The antioxidant capacity was measured in all fig fruits as well. It has been shown that the temperature of extraction and ethanol to water ratio have a statistically significant influence on the extraction of phenolic compounds from fig fruits variety Šaraguja. The highest content of phenolic compounds was found in fig variety Crnica while the lowest one in fig variety Bjelica. According to the results obtained in this study, fig fruits can be considered as a natural source of phenolic compounds with good antioxidant capacity.

Simulation, calculation and possibilities of energy saving in spray drying process

In this work some possibilities to improve the conventional spray drying process using programming in Excel as a calculation tool have been presented. The program gives a simple description of the drying process using thermodynamic calculations of heat and mass balance. Using the program it is possible to reduce operating costs and to improve capacity per unit of drying equipment. The minimization of energy consumption during the drying operation can be achieved by recycling exhaust air. The maximum theoretical range of recirculation is 60%. The fuel oil saving rate depends linearly on the rate of recirculation, and the theoretical maximum fuel oil saving is approximately 14%. Ecological issues were also considered as well, since decreased fuel consumption lowers harmful gas emission to the environment. All necessary data are represented in the process flow sheet, which is used for a better understanding of the drying process optimisation.

Evaluation of Quercetin Content, Colour and Selected Physico-Chemical Quality Parameters of Croatian Blackberry Wines

Abstract Blackberry wine, the most widespread Croatian fruit wine, is produced by yeast fermentation of raw blackberry juice or must. Even though the production and intake of blackberry wine in Croatia has been increasing for years, the available data on the overall quality and blackberry wine composition is still scarce. The objective of this work was to evaluate the quercetin content, colour and selected physico-chemical quality parameters of 15 Croatian blackberry wine samples, divided into two groups denominated as CWB and OWB regarding the blackberries’ cultivation type (conventional and organic). The quercetin content ranged from 0.81 to 21.67 mg/L (average: 6.16 mg/L, median 3.96 mg/L) and was consistent with some published studies. Compared to CBW group, quercetin content of OBW samples seemed to be more balanced and slightly higher (OBW median: 3.99 mg/L, CWB median: 1.80 mg/L). The presence of cyanidin and pelargonidin (as aglycons) was detected in very low concentrations in four and seven samples, respectively. Determination of the colour revealed that the most important component contributing to colour intensity was yellow (51 %), followed by red (40 %). The chemical quality parameters were in accordance with the available published results on blackberry and grape wines and were as follows: relative density 1.0017–1.0660 g/mL, concentration of reducing sugars 13.5–177.6 g/L, alcoholic strength 9.37–14.78% vol, pH 3.11–3.56, total acidity 6.7–18.1 g/L, ash 1.59–4.11 g/L, alkalinity of ash 1.54–3.79 g/L, total nitrogen 65.50–361.15 mg/L, and total phosphorus 32.03–118.53 mg/L. No significant overall differences were noticed between the conventional and organic group of samples.

Blackberry wines mineral and heavy metal content determination after dry ashing: multivariate data analysis as a tool for fruit wine quality control

Abstract This study brings out the data on the content of 21 mineral and heavy metal in 15 blackberry wines made of conventionally and organically grown blackberries. The objective of this study was to classify the blackberry wine samples based on their mineral composition and the applied cultivation method of the starting raw material by using chemometric analysis. The metal content of Croatian blackberry wine samples was determined by AAS after dry ashing. The comparison between an organic and conventional group of investigated blackberry wines showed statistically significant difference in concentrations of Si and Li, where the organic group contained higher concentrations of these compounds. According to multivariate data analysis, the model based on the original metal content data set finally included seven original variables (K, Fe, Mn, Cu, Ba, Cd and Cr) and gave a satisfactory separation of two applied cultivation methods of the starting raw material.