Aleksandra Tepić

Optimization of frozen sour cherries vacuum drying process.

The objective of this research was to optimize the vacuum-drying of frozen sour cherries in order to preserve health-beneficial phytochemicals, as well as textural characteristics. Investigated range of temperature was 46-74°C and, of pressure, 17-583mbar, in a new design of vacuum-dryer equipment. The total solids, a(w) value, total phenolics, vitamin C, antioxidant activity, anthocyanin content, total colour change and firmness were used as quality indicators of dried sour cherry. Within the experimental range of studied variables, the optimum conditions of 54.03°C and 148.16mbar were established for vacuum drying of sour cherry. Separate validation experiments were conducted, under optimum conditions, to verify predictions and adequacy of the second-order polynomial models. Under these optimal conditions, the predicted amount of total phenolics was 744mg CAE/100 dw, vitamin C 1.44mg/100g per dry weight (g dw), anthocyanin content 125mg/100g dw, IC(50) 3.23mg/ml, total solids 70.72%, a(w) value 0.646, total colour change 52.61 and firmness 3395.4g. The investigated parameters had a significant effect on the quality of the dried sour cherries.

Modeling and optimization of red currants vacuum drying process by response surface methodology (RSM).

Fresh red currants were dried by vacuum drying process under different drying conditions. Box-Behnken experimental design with response surface methodology was used for optimization of drying process in terms of physical (moisture content, water activity, total color change, firmness and rehydratation power) and chemical (total phenols, total flavonoids, monomeric anthocyanins and ascorbic acid content and antioxidant activity) properties of dried samples. Temperature (48-78 °C), pressure (30-330 mbar) and drying time (8-16 h) were investigated as independent variables. Experimental results were fitted to a second-order polynomial model where regression analysis and analysis of variance were used to determine model fitness and optimal drying conditions. The optimal conditions of simultaneously optimized responses were temperature of 70.2 °C, pressure of 39 mbar and drying time of 8 h. It could be concluded that vacuum drying provides samples with good physico-chemical properties, similar to lyophilized sample and better than conventionally dried sample.

Effects of Onion (Allium cepa L.) and Garlic (Allium sativum L.) Essential Oils on the Aspergillus versicolor Growth and Sterigmatocystin Production

In the present study the effects of individual and combined essential oils (EOs) extracted from onion (Allium cepa L.) bulb and garlic (Allium sativum L.) clove on the growth of Aspergillus versicolor and sterigmatocystin (STC) production were investigated. The EOs obtained by hydrodistillation were analyzed by GC/MS. Twenty one compounds were identified in onion EO. The major components were: dimethyl-trisulfide (16.64%), methyl-propyl-trisulfide (14.21%), dietil-1,2,4-tritiolan (3R,5S-, 3S,5S- and 3R,5R- isomers) (13.71%), methyl-(1-propenyl)-disulfide (13.14%), and methyl-(1-propenyl)-trisulfide (13.02%). The major components of garlic EO were diallyl-trisulfide (33.55%), and diallyl-disulfide (28.05%). The mycelial growth and the STC production were recorded after 7, 14, and 21 d of the A. versicolor growth in Yeast extract sucrose (YES) broth containing different EOs concentrations. Compared to the garlic EO, the onion EO showed a stronger inhibitory effect on the A. versicolor mycelial growth and STC production. After a 21-d incubation of fungi 0.05 and 0.11 μg/mL of onion EO and 0.11 μg/mL of garlic EO completely inhibited the A. versicolor mycelial growth and mycotoxins biosynthesis. The combination of EOs of onion (75%) and garlic (25%) had a synergistic effect on growth inhibition of A. versicolor and STC production.

Pigment content and fatty acid composition of paprika oleoresins obtained by conventional and supercritical carbon dioxide extraction

An experiment was conducted to examine the influence of conventional and supercritical extraction of ground paprika (“Aleva N.K.” variety) on the quality of paprika oleoresin. Paprika was extracted using hexane as an organic solvent and supercritical carbon dioxide at 20, 30 and 40 MPa. The extraction yields were 12.8, 10.6, 10.6 and 10.3%, respectively. It was confirmed that the organic solvent was less selective than the supercritical carbon dioxide. The analyses of fatty acid composition showed that oleoresin consisted mostly of linoleic acid. The highest pigment content was found in the conventional oleoresin, 31,476 mg/kg. Among supercritical oleoresins, the richest in pigments was the one obtained at 40 MPa (14,134 mg/kg), 44.9% in comparison with the conventional.

Chemometric guidelines for selection of cultivation conditions influencing the antioxidant potential of beetroot extracts

Display Omitted 64 beetroot samples were cultivated under different conditions.Novel approach to samples similarity analysis was applied.The differences between the samples were detected.ANN-R model best predicts antioxidant activity of beetroot extracts. The estimation of influences of different cultivation conditions on chemical composition of crops can be quite complex task. Usually, the classical statistic approach (comparison of statistical characteristics of different populations) is applied. However, this study presents the analysis of the influence of different cultivation conditions (cultivation with or without foil cover, different preceding crops and fertilization) on the contents of dry matter, betalains and phenolic compounds in 64 beetroot (Beta vulgaris L. ssp. vulgaris) samples and their antioxidant potential (IC50) by using powerful chemometric tools, such as Wald-Wolfowitz run test, cluster analysis and sum of ranking differences, in order to obtain groupings of the samples which share similar properties or to test if the samples come from the same population. Besides the aforementioned classification or pattern recognition analysis, the regression methods (linear, multiple linear and artificial neural network regressions) were carried out in order to establish reliable linear and non-linear relationships between IC50 and contents of betalains, phenolic compounds and dry matter. The results reveal certain influence of foil cover, used during the cultivation, on beetroot antioxidant potential and content of the determined betalains and phenolic compounds, as well as the strong non-linear relationship between the analyzed variables. Certain influence of preceding crops on phenolic compounds content is detected by Wald-Wolfowitz run test.

Effect of extraction conditions of paprika oleoresins on their free radical scavenging and anticancer activity

AbstractGround spice paprika was extracted with hexane, by conventional Soxhlet procedure (SX oleoresin), and with supercritical carbon dioxide at three different pressures — 20, 30 and 40 MPa (SF20, SF30 and SF40 oleoresins). The effect of extraction method and conditions on the colour intesity of paprika oleoresins, content of α-tocopherol, as well as antioxidant and antiproliferative activity was examined. Hexane showed highest selectivity for paprika pigments (886.02 ASTA), while α-tocopherol showed highest solubility (3846.9 mg kg−1) in supercritical carbon dioxide at 20 MPa. All paprika oleoresins exhibited good superoxide anion radical scavenging activity SF30 being the best superoxide anion radical scavenger. Cell growth activity was evaluated in vitro in human cell lines:cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT-29). The highest antiproliferative activity was exhibited by SX in MCF7 cell line (IC50=14.28 mg mL−1). Extract SF40 produced significant and selective antiproliferative action towards HeLa cell line. These results suggest that paprika oleoresins, due to high antiradical and tumor cell-inhibiting activity, can be regarded as functional food ingredients.

Influence of particle diameter on the colour of ground pepper (Capsicum annuum L.)

The influence of particle diameter of ground paprika on its colour was examined in this study. Six samples of industrial ground paprika, from various phases of milling, and different particle size were purchased from the factory. Extractable colour (ASTA) and surface colour (L, a*, b*, C, λ), as the most important colour indicators, were measured. Increasing the grinding level caused the increase of ASTA and red coordinate (a*) value, and decrease of yellow coordinate (b*) value, as well as lightness of the samples, as a consequence of the increase of the specific surface area of sample particles.

The influence of protective properties of packaging materials and application of modified atmosphere on packed dried apricot

The influence of protective properties of packaging materials and modified atmosphere on quality changes of dried apricot is shown in this paper. In our investigation, we used four different characteristic combinations of packaging materials with different barrier properties for packaging of dried apricot: polyester-polyethylene (PET/PE), paper-polyethylene (PAP/PE), paper-aluminium-polyethylene (PAP/Al/PE), polyester-aluminium-polyethylene (PET/Al/PE) and two different atmospheric conditions: normal and modified (30% CO 2 , 60% N 2 ). The parameters evaluated in this study were moisture content, the content of the brown component and the hidroxymethilfurfural (HMF) content. During the storage period of 12 months, changes in moisture content, and colour changes of brown component and HMF contents were affected by the type, combination and applied packing conditions. During the investigation period, the moisture content increased, as well as the content of the brown component and the HMF content. The highest changes in moisture content are reported for dried apricot packaged in the PAP-PE under normal atmosperic condition (increased from 31.2 to 39.6%, taking into consideration 100 g of the sample, after 12 months of storage). The highest value of HMF content was recorded for dried aprricot packaged in the PAP-Al-PE with modified atmospheric condition after nine months of storage (0.152 mg/g). The research results indicate that sustainability of dried packaged apricot is affected by the selection of packaging material and the applied atmospheric conditions. Keywords: Packaging, modified atmosphere, dried apricot