Štefan Schmidt

Preparation of modified fats from vegetable oil and fully hydrogenated vegetable oil by randomization with alkali catalysts

Randomization of fat blends, formulated by mixing vegetable oil with fully hydrogenated vegetable oil in various ratios, using alkali catalysts, have been investigated. The relationship between the structure and physical properties was examined. The fatty acid and triacylglycerol composition of each original fat blend and the randomization products together with the physical properties such as melting, crystallization characteristics and solid fat content were correlated. The differences in the exothermic and endothermic peak temperatures, melting points and solid fat content among the fat blends showed the effects of the composition on the physical properties.

Effect of evening primrose extracts on oxidative stability of sunflower and rapeseed oils

Antioxidative activities of evening primrose seed meal extracts in sunflower and rapeseed oils were compared with that of commercially used antioxidants, namely butylated hydroxytoluene (BHT), ascorbylpalmitate as well as Grindox-118. The study was carried out under Schaal oven conditions at 60 °C and the weight gain was followed up by p-anisidine value measurement following the oxidation. An Oxidograph apparatus monitored the oxidation of oils at 110 °C. Among the examined extracts, the ethyl acetate extract (0.2%), containing only 87 mg/g of total phenolics, exhibited a stronger antioxidant activity than BHT (0.01%) and effectively stabilised both oils. A strong antioxidative effect was also noted for the ethanol-ethyl acetate extract (168 mg/g of total phenolics). The study showed that addition of ethyl acetate and ethanol-ethyl acetate extracts could extend the sunflower and rapeseed oils shelf-life by protecting oils from further decomposition that naturally occurs during thermal treatments.

Plant-derived surfactants as an alternative to synthetic surfactants: surface and antioxidant activities

Biosurfactants have great advantages as an eco-friendly alternative to synthetic surfactants. Surface active properties and antioxidant activity of extracts prepared from Sapindus mukorossi, Verbascum densiflorum, Equisetum arvense, Betula pendula and Bellis perennis have been studied. The extract from Sapindus mukorossi served as a standard because it belongs to the most widely used natural surfactants. The surface active properties of these nonionic surfactants were also compared with the properties of common synthetic surfactants such as sodium lauryl sulfate (SLS) and Tween® 80. In many cases, the plant-derived surfactants showed better properties than the synthetic ones, e.g. minimum critical micelle concentration values were observed for E. arvense (0.033 g L−1), B. perennis (0.076 g L−1), or minimum surface tension reached for the extract of B. perennis (36.8 mN m−1).

Multiple functions of caprylic acid-induced impurity precipitation for process intensification in monoclonal antibody purification

New emerging technologies delivering benefits in terms of process robustness and economy are an inevitable prerequisite for monoclonal antibody purification processes intensification. Caprylic acid was proven as an effective precipitating agent enabling efficient precipitaton of product- and process-related impurities while leaving the antibody in solution. This purification step at mild acidic pH was therefore introduced in generic antibody platform approaches after Protein A capture and evaluated for its impact regarding process robustness and antibody stability. Comparison of 13 different monoclonal antibodies showed significant differences in antibody recovery between 65-95% during caprylic acid-induced impurity precipitation. Among six compared physicochemical properties, isoelectric point of the antibody domains was figured out to correlate with yield. Antibodies with mild acidic pI of the light chain were significantly susceptible to caprylic acid-induced precipitation resulting in lower yields. Virus clearance studies revealed that caprylic acid provided complete virus inactivation of an enveloped virus. Multiple process relevant factors such as pH range, caprylic acid concentration and antibody stability were investigated in this study to enable an intensified purification process including caprylic acid precipitation for HCP removal of up to 2 log10 reduction values at mAb yields >90% while also contributing to the virus safety of the process.

Composition of fatty acids and tocopherols in peels, seeds and leaves of Sea buckthorn

Abstract Peels, seeds and leaves of the Sea buckthorn were extracted by methanol and chloroform and characterized in terms of the fatty acids (FA) and tocopherol composition. All morphological parts of Sea buckthorn contained these biologically active compounds useful in medicine, pharmacology, human nutrition and cosmetics. The highest amount of α-tocopherol was found in peels (1103 mg kg-1). The lowest content of α-tocopherol was found in leaves (659 mg kg-1). Delta-tocopherol was found in higher amount in peels 1757 mg kg-1. Seeds contained 95 mg kg-1 of delta-tocopherols. Gamma-tocopherol was found in seeds (459 mg kg-1), peels (188 mg kg-1) and in leaves (587 mg kg-1). β-tocopherol was present only in seeds (171 mg kg-1). Unsaturated fatty acids were dominant in all morphological parts of Sea buckthorn. The highest amounts of unsaturated fatty acids (92 rel. %) were determined in seeds. Dominant fatty acids of seeds were linoleic acid (37 %), α-linolenic acid (30 %) and vaccenic acid (20 %). Leaves were rich in α-linolenic acid (51 %). Dominant fatty acids of peels were oleic acid (16 %), palmitic acid (33 %) and palmitoleic acid (29 %).

Antibacterial and antifungal activity of phytosterols and methyl dehydroabietate of Norway spruce bark extracts

The current study focuses on the analysis of in vitro biological activity of extract from bark of Norway spruce (Picea Abies), which can find potential application in food and cosmetic industry and pharmacology. Milled bark was subjected to Soxhlet extraction and supercritical fluid extraction to obtain two ethanol extracts. These extracts were further used to obtain their pre-extracts to n-hexane. It was investigated whether beta-sitosterol exhibits bacteriostatic activity necessary to observe antimicrobial and antifungal activity of methyl dehydroabiatate. This synergic effect and bacteriostatic activity of beta-sitosterol have not been previously reported. The greatest inhibition zone of n-hexane pre-extracts was confirmed in bacterium Pseudomonas aeruginosa (0,9 - 1,5 cm) and yeast Alternaria alternata (0,7 - 1,6 cm). It is novel, the antioxidant, antimicrobial and antifungal activity of spruce bark extracts assessed in terms of food and cosmetic fortification.

Influence of storage and microwave heating on stability of soya spread lipids with linseed content

Influence of storage and microwave heating on stability of soya spread lipids with linseed content We have chosen to experiment with soya spreads containing linseeds, which enrich the spreads with essential fatty acids and valuable related substances. The soya spreads with linseeds represent an ideal combination for nutritionally valuable foods with health benefits. In this work we examined the influence of microwave heating and storage on stability of linseed oil and soya spread lipids. Industrially produced soya spreads (S1) with addition of 5, 7 and 10 % linseeds and linseed oil were stored without a protective atmosphere in refrigerator at 5 °C. The lipids of commercial soya spreads (S2) enriched with 2, 5 and 10 % ground linseeds and soya spread lipids (S2) without linseeds were microwave-heated. The data obtained from experiments have shown that the storing of linseed oil for 30 days in refrigerator has caused excess of the maximum acceptable peroxide value (Food Codex of SR). Microwave-heated lipids from commercial soya spreads (S2) enriched with 2 % ground linseeds have the best result of stability and protective factor, compared with lipids from 5 and 10 % linseeds enriching soya spreads (S2). After the 5, 10 and 20 min of microwave heating, the lipids of soya spread (S2) enriched with 2 % ground linseeds have the protective factor 1.02, 1.15 and 1.43 respectively, compared with lipids from soya spread (S2) without linseeds. The microwave heating for 5 min has been accompanied by a decreasing of hydroperoxides and by formation of secondary oxidation products.

Influence of rapeseed meal on lard stability

Abstract The experiment focused on the possibility to utilise the antioxidant potential of rapeseed meal to stabilize fats. The lard, which was used for this purpose, was characterized by gas chromatography. At first the non-sieved meal was added in lard. It is the least technologically difficult method of utilizing meal. Then, the meal was sieved to obtain five fractions, which were added to lard. The aim was to find a fraction of meal that would best stabilize the lard. The results of lard stability with added fractions were compared with the stability of lard enriched with non-sieved meal. Finally, we obtained ethanol and ethyl acetate extracts from non-sieved meal and from the fraction which was the best stabiliser of lard. The aim was to study the effect of these extracts on the stability of lard. Rapeseed meal has stabilized the lard already at 0.5 wt. % content. The non-sieved meal addition of 1, 2 or 4 wt. % has improved the stability of lard by 1.2-2 times. Adding 8-15 wt. % of meal into lard has increased its stability by 3-8 times. The best lard stability has been determined in the fraction retained on the sieve with mesh size 0.15 mm. The lard with added sieved meal has gained a comparable stability the same as after addition of non-sieved meal. The lard with the same additions of extracts (ethanol and ethyl acetate) from non-sieved meal and from meal with sizes 0.15-0.315 mm was more stable than the lard with addition of meal alone. The lard containing ethanol extracts (0.5 wt. %) has a better stability than the lard containing butylated hydroxytoluene (0.02 wt. %).