Phytochemical composition and antimicrobial activities of the essential oils from Satureja subspicata Vis. growing in Croatia

The present study describes the phytochemical profile and antimicrobial activity of Satureja subspicata Vis. essential oils, collected in Dalmatia (Croatia). Three samples of essential oils were obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC–MS. From the 24 compounds representing 97.47% of the oils, carvacrol (16.76%), α-pinene (13.58), p-cymene (10.76%), γ-terpinene (9.54%) and thymol methyl ether (8.83%) appear as the main components. The oils also contained smaller percentages of myrcene, linalool, β-caryophyllene, limonene, geranyl acetate, 1-Octen-3-ol, nerol, thymol and borneol. Furthermore, antimicrobial activity of the oil was evaluated using agar diffusion and broth microdilution methods. The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria and 9 fungal strains. Gram-positive bacteria are more sensitive to the investigated oil, with a range of 0.09 to 6.25 μl/ml than Gram-negative bacteria in the range which is significantly higher from 1.56 to 25.00 μl/ml. Results presented here may suggest that the essential oil of S. subspicata possesses antimicrobial properties, and is therefore a potential source of antimicrobial ingredients for the food and pharmaceutical industry.     

Rheological and Breadmaking Properties of Wheat Flours Supplemented with Octenyl Succinic Anhydride-Modified Waxy Maize Starches

The feasibility of emulsifying starches as bread improvers was investigated by incorporating starch sodium octenyl succinate (OSA-st), pre-gelatinized OSA-st and hydrolysed spray-dried OSA-st at 2.5, 5 and 10 % into wheat flour. Dough rheological properties (creep and recovery measurements; Mixolab, Alveograph) and bread quality parameters (specific loaf volume, crust and crumb colour, crumb moisture, crumb grain features, texture) were evaluated. The substituted flours, except hydrolysed OSA-st, significantly increased water absorption measured by Mixolab. The study on the rheological behaviour of doughs containing emulsifying starches, performed using a rheometer and an Alveograph, showed that OSA-st incorporation yielded strengthened dough, whereas pre-gelatinized and hydrolysed OSA-st addition led to more extensible dough. With regard to the thermal behaviour, investigated in water-limited systems by Mixolab, doughs prepared from pre-gelatinized OSA-st and hydrolysed OSA-st exhibited lower maximum peak torque, whilst all three examined starches increased cooking stability and decreased the setback value. Specific volumes of loaves baked from the substituted flours increased, and the highest effect was observed with pre-gelatinized OSA-st, which consequently produced bread crumbs with the largest mean gas cell area. The bread crumbs baked with octenyl succinate starches were whiter and softer. Although upon 1 day of storage no significant moisture retention capacity of emulsifying starches was noticed, the firmness values of OSA-st and pre-gelatinized OSA-st-supplemented bread crumbs, after 24 h of storage, were similar to or significantly lower than those of the control determined 2 h after baking. The obtained results indicate a requirement for further optimization of the octenyl succinate starch-supplemented doughs in terms of the combination of different types and levels of modified starches in order to obtain maximum bread quality.     

Cow colostrum and early milk enriched with eicosapentaenoic and docosahexaenoic fatty acid

The objective of the study was to explore whether it is possible to alter cow colostrum and early milk fatty acid composition with a low level of fat supplement, high in docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acid. Diets included a control diet and a diet supplemented with DHA- and EPA-enriched fat supplement. Addition of fat supplement significantly decreased saturated fatty acids, C14:0 and C16:0 and increased the values of monounsaturated fatty acids, polyunsaturated fatty acids (PUFA), n3 fatty acids, EPA, DHA, C18:1n9cis and C18:1n11trans. The percentage of short-chain fatty acids significantly increased with the progress of lactation, while the percentage of PUFA, n3 and n6 significantly decreased. These results showed that fat supplement, high in DHA and EPA, modified the fatty acid profile of colostrum and milk fat and increased the proportion of beneficial fatty acids for human health.     

The involvement of oxidative stress in ochratoxin A and fumonisin B1 toxicity in rats

The aim of this study was to find out whether very low doses of nephrotoxic and hepatotoxic mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1) induce oxidative stress in rat kidney and liver and whether their effect is synergistic. Rats were treated orally with OTA (5 ng/kg b.w. and 50 microg/kg b.w.) and FB1 (200 ng/kg b.w. and 50 microg/kg b.w.), or their combinations. Malondialdehyde (MDA) and protein carbonyls (PCs) concentration in kidney was affected with lower dose of OTA than in liver (p<0.05). FB1 did not affect MDA and PCs concentrations in the liver, while in the kidney both FB1 doses increased MDA concentration (p<0.05). The combination of the lower doses of OTA+FB1 increased the MDA and PCs concentration both in the liver and the kidney, compared to controls and animals treated with respective doses of mycotoxins (p<0.05). The combinations of mycotoxins reduced the catalase activity only in the kidney when compared to controls (p<0.05). In contrast to the increased kidney concentrations of MDA and PCs even with very low doses of OTA and FB1, the activity of catalase and SOD does not change. Combinations of OTA+FB1 affected almost all parameters, which indicates their potential to produce oxidative damage.     

Wheat flour confectionery products as a source of inorganic nutrients: zinc and copper contents in hard biscuits

Cereal-based confectionery products being consumed through whole human life are considered mainly to be a source of carbohydrates, that is energy, although cereals are a rich source of minerals as well. To evaluate some hard biscuits produced in Croatia as a source of different trace elements in nutrition, in this study Zn and Cu contents were determined in classic wheat flour biscuits and in dietetic biscuits enriched with whole wheat grain flour or whole wheat grain grits, soya flour and skimmed milk. Zn was determined by flame atomic absorption spectrometry (AAS); Cu was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The results show that the Zn content in different kinds of biscuits ranges from 5.89 up to 17.64 mg/kg and the Cu content ranges from 1.15 up to 2.79 mg/kg depending on the type of wheat milling products and mineral content of other ingredients used. Enriched dietetic biscuits produced from wheat flour type 850 and whole wheat grain flour and/or soya flour and skimmed milk were almost 200% and 150% higher in Zn and Cu, respectively, in comparison to classic white wheat flour biscuits and can be considered as good sources of Zn and Cu in nutrition.     

SWCNT-modified carbon paste electrode as an electrochemical sensor for histamine determination in alcoholic beverages

In this work, a simple and rapid electrochemical method is presented for the voltammetric determination of histamine based on carbon paste electrodes bulk-modified with single-walled carbon nanotubes. As monitored in cyclic voltammetry histamine undergoes an irreversible electrochemical oxidation with a peak potential of ca. +1.25 V (vs. Ag/AgCl, 3 mol L^?1 KCl) in phosphate buffer solution (PBS, 0.1 mol L^?1, pH 6.0). At optimized differential pulse voltammetric parameters, the current response of histamine was linearly proportional to its concentration in the range from 4.5 to 720 μmol L^?1. A low limit of detection of 1.26 μmol L^?1 and a limit of quantification of 3.78 μmol L^?1 of histamine, as well as good reproducibility (RSD?=?0.48–3.40 %) were obtained using the carbon paste electrode modified with single-walled carbon nanotubes. The proposed sensor was successfully applied to the determination of histamine in commercial beer and wine samples.     

Effect of supercritical CO2 extraction process parameters on oil yield and pigment content from by‐product hemp cake

This research gives an insight into the possibility of exploiting the one of the food industry's by‐products – pressed hemp cake. The complete recovery of oil from pressed hemp cake was achieved. Residual oil that remained in cake after pressing was extracted with supercritical CO₂ by applying different process parameters. Optimal extraction conditions were determined using response surface methodology. Total pigment contents of the oils obtained were determined. Extraction pressure had the most significant influence on yield and pigment content of extracted hemp cake oil. Depending on the pressure, the chlorophyll a content ranged from 101.11 to 378.28 mg kg^?1 and chlorophyll b from 65.14 to 189.78 mg kg^?1, while total carotene content was in the range from 33.58 to 132.67 mg kg^?1. The remaining oil in pressed hemp cake after supercritical CO₂ extraction was determined to be 0.56 ± 0.08% and the defatted cake was rich in proteins and fibre.     

Bread and durum wheat compared for antioxidants contents,and lipoxygenase and peroxidase activities

Potential beneficial components, including proteins, total phenolics, total flavonoids, carotenoids, tocopherols, and DPPH radical scavenging activity, were investigated in wholemeal of ten bread (T. aestivum L.) and ten durum (T. durum Desf.) novel wheat genotypes. In addition, the activity rate of lipoxygenase (LOX) and peroxidase (POD) enzymes implicated in the antioxidant metabolism was determined. The protein contnet and the antioxidant properties varied according to the two different wheat species, as well as, between the different bread and durum wheat genotypes themselves. The results indicated significant differences in proteins and antioxidant compounds between bread and durum wheat. Higher total proteins, wet gluten and antioxidants contents, combined with lower LOX and POD activities, point to a higher nutritive value of durum wheat than bread wheat.