Addition of natural antioxidants such as rosemary extract or lutein is usually limited. The effects of such antioxidants reduce the formation of trans fatty acids during oil thermal treatment. The intake of foods containing trans fatty acids (TFAs) can have deleterious effects on human health, mainly on the cardiovascular system. Thus, it is important to consider the processes that form TFAs in foods, and the alternatives to minimise their formation. The influence of two added natural antioxidants on TFA formation during heat treatment (120 h at 180 degrees C) of sunflower vegetable oil were examined: rosemary extract (Rosmarinus officinalis L.) (1 g per kg oil) and lutein (0.1 g per kg oil). Changes in FA composition were determined using Ag-ion SPE and gas-liquid chromatography, with total polar compounds determined using dielectric constant measurements and the index of atherogenicity was calculated. Total TFAs with )= 1 trans double bond increased from 0.91 to 1.71% in control samples; this increase was significantly less with both rosemary extract (1.55%) and lutein (1.43%) additions. Among the individual TFAs, significant increases were seen for C18:1,t-9, C18:2,t-9,t-12 and C18:2,c-9,t-12/9-t,12-c. Polar compounds also increased, with the highest concentrations in control samples, and significantly less with both rosemary extract and lutein additions. According to results of our study, we can summarize that addition of lutein have greater effect on reduction of TFA formation than rosemary extract.
COBISS.SI-ID: 3827576
The flavonoid profiles of seven types of Slovenian honey were analysed. The flavonoids were extracted from honey samples by solid-phase extraction and analysed by liquid chromatography with mass spectrometry. The honey samples had similar, but quantitatively different, flavonoid profiles. The analysis did not show any specific compounds to use as markers for determination of the botanical origins of these different types of Slovenian honey. Linear discriminant analysis correctly classified 85% of these honey samples according to their botanical origins.
COBISS.SI-ID: 3869048
The aim of this study was to determine whether supplemental addition of coenzyme Q10 and ascorbic acid or a-tocopherol, either alone or together, can prevent oxidative damage in chicken liver pâté, as reflected by reduced formation of cholesterol oxidation products (COPs) and by preservation of sensorial quality. Separate groups of chicken liver pâtés had no supplements (control) or were supplemented with coenzyme Q10 (0.2 g/kg) and either ascorbic acid (2 g/kg) or a-tocopherol (0.2 g/kg), or both. All products were pasteurised (82 °C) or sterilised (121 °C). Four COPs were found: 7α-, 7β-, 20α- and 25-hydroxycholesterol. The COP radical scavenger function of coenzyme Q10 (control, 5.16 mg/kg; plus Q10, 3.94 mg/kg) and the synchronous actions of coenzyme Q10 and a-tocopherol (2.6 mg/kg) were confirmed in sterilised pâtés. Generally, in pasteurised and sterilised pâtés, the most efficient scavenger function was with ascorbic acid either alone or together with a-tocopherol, where the formation of COPs was below the limit of detection. An increase of 1.9 mg/kg in COP production during heating was also seen in samples without added antioxidants. There was a weak interdependence between the content of COPs and the sensory parameters of the pâté. For addition of antioxidants, in the pasteurised pâté, colour and smell were slightly improved, but flavour deteriorated; in the sterilised pâté, colour was slightly worse, with a more tender texture. Overall, instrumentally measured colour and sensory properties (except texture) showed no significant differences between pasteurisation and sterilisation.
COBISS.SI-ID: 3834744