Dorota Żyżelewicz

New trends in quantification of acrylamide in food products

Methods applied in acrylamide quantification in foods have been reviewed in this paper. Novel analytical techniques like capillary electrophoresis (CE), immunoenzymatic test (ELISA) and electrochemical biosensors, which can replace traditional methods like high performance liquid chromatography (HPLC) and gas chromatography (GC) were presented. Short time of analysis and high resolution power of electrophoretic techniques caused that they became routinely used in food analysis apart from high performance liquid chromatography and gas chromatography. Application of modern chromatography methods like ultra performance liquid chromatography (UPLC) in acrylamide quantification considerably shortened the time of analysis and decreased the consumption of indispensable reagents. The most promising approaches to acrylamide quantification in foods are electrochemical biosensors and immunoenzymatic tests. In contrast to chromatography and electrophoretic methods they require neither expensive equipment nor time consuming sample preparation and allow for fast screening of numerous samples without the usage of sophisticated apparatuses. Because of many advantages such as miniaturization, rapid and simple analysis, and high sensitivity and selectivity, biosensors are thought to replace conventional methods of acrylamide quantification in food.

Application of various methods for determination of the color of cocoa beans roasted under variable process parameters

Cocoa beans of Forastero variety from Togo were subjected to roasting under either constant or variable process parameters. The variable process parameters were roasting air flow rate, temperature and relative humidity. The color of roasted cocoa beans was determined by pigment extraction under various conditions followed by either their spectrophotometric assays or CIE L*a*b measurements. Also the Maillard compounds index and total polyphenols content correlated with progress of the browning of beans were determined. It was found that an increase in the roasting air relative humidity stimulated formation of brown pigments, while elevated temperature caused worsening of color parameters of roasted cocoa beans. The most suitable method of color characterization of roasted cocoa beans was found to be pigments extraction combined with either separation of their fractions or CIE L*a*b measurements. These assays revealed that cocoa beans roasted under variable roasting air flow rate were characterized by improved color parameters. The relatively simple and inexpensive CIE L*a*b measurements ensured fast analysis of color parameters, while total polyphenols in roasted cocoa beans were quickly estimated by using F–C reagent. Furthermore, quantification of melanoid pigments in roasted cocoa beans can be based on determination of the index of nonenzymatic browning products content, which is relatively simple and inexpensive.

Centrifugal partition chromatography – A review of recent applications and some classic references

Countercurrent chromatography, based on liquid-liquid partitioning, has many technological variants. One of them is centrifugal partition chromatography, introduced by Wataru Murayama and Kanichi Nunogaki in 1982. This technique, like other countercurrent chromatography techniques, is based on the phenomenon of liquid-liquid partitioning between two immiscible liquid phases that stay at equilibrium. But the significant difference between this technique and others is the retention mechanism of stationary phase. In the case of centrifugal partition chromatography, this mechanism is based on hydrostatic force, formed by the centrifugal field in the rotor in one-axis centrifuge. Sometimes that allows more control of stationary phase, for example, when aqueous two-phase and other difficult solvent systems are used. However, the efficiency of the separation in centrifugal partition chromatography is also affected by a variety of parameters dependent on the sample properties in the solvent system, physical properties of the solvent system, parameters of the instrument, and the method. This article includes also recent ideas for improvements to the technique and broadening its application (e.g., (multiple) dual-mode or elution-extrusion procedure, pH-zone-refining centrifugal partition chromatography, ion-exchange centrifugal partition chromatography, online and offline coupling of centrifugal partition chromatography).

Phenolic Profile and Antioxidant Potential of Leaves from Selected Cotoneaster Medik. Species

The antioxidant efficiency of 70% aqueous methanolic extracts from the leaves of twelve selected Cotoneaster Medik. species was evaluated using four complementary in vitro tests based on SET- (single electron transfer) and HAT-type (hydrogen atom transfer) mechanisms (DPPH, FRAP, O2•− and H2O2 scavenging assays). The samples exhibited the dose-dependent responses in all assays with activity parameters of EC50 = 18.5–34.5 µg/mL for DPPH; 0.9–3.8 mmol Fe2+/g for FRAP; SC50 = 27.7–74.8 µg/mL for O2•−; and SC50 = 29.0–91.3 µg/mL for H2O2. Significant linear correlations (|r| = 0.76–0.97, p < 0.01) between activity parameters and total contents of phenolics (5.2%–15.4% GAE) and proanthocyanidins (2.1%–15.0% CYE), with weak or no effects for chlorogenic acid isomers (0.69%–2.93%) and total flavonoids (0.28%–1.40%) suggested that among the listed polyphenols, proanthocyanidins are the most important determinants of the tested activity. UHPLC-PDA-ESI-QTOF-MS analyses led to detection of 34 polyphenols, of which 10 B-type procyanidins, 5 caffeoylquinic acids and 14 flavonoids were identified. After cluster analysis of the data matrix, the leaves of Cotoneaster zabelii, C. splendens, C. bullatus, C. divaricatus, C. hjelmqvistii and C. lucidus were selected as the most promising sources of natural antioxidants, exhibiting the highest phenolic levels and antioxidant capacities, and therefore the greatest potential for pharmaceutical applications.

Green and roasted coffee extracts as antioxidants in βTC3 cells with induced oxidative stress and lipid accumulation inhibitors in 3T3L1 cells, and their bioactivity in rats fed high fat diet

Chlorogenic acids from coffee show high antioxidant activity that contributes to inhibition of oxidative stress, which results in anticancer, antidiabetic and antiobesity coffee activities. Coffee roasting causes their partial decomposition and partial incorporation into Maillard reaction products also of high antioxidant activity, and it is still not clear whether more favorable impact on health is associated with the consumption of green or roasted coffee. The aim of the study was to evaluate the impact of coffee roasting process and also of the degree of chlorogenic acid esterification on bioactivity of coffee extracts. Extracts of green and roasted coffee and their fractions containing mono- and dichlorogenic acids (six extracts) were obtained by purification and optional fractionation of crude extracts using preparative centrifugal partition chromatography technique. The extracts were evaluated in vitro in terms of scavenging capacity, influence on lipids accumulation in 3T3L1 adipocytes, cytoprotective potential decreasing oxidative stress induced by cellular pro-oxidants in βTC3 cells, and in vivo by selected physiological indices in rats fed diets supplemented with the extracts. Roasted coffee extracts, in particular hydrophilic fraction containing monochlorogenic acids and Maillard reaction products, showed the highest scavenging capacity and contributed to the highest level of antioxidants in the hydrophilic fraction of rats serum and may be potentially used as anticancer nutraceutical with oxidative stress inhibitor activity. Non-fractionated green coffee extract exhibited antidiabetic activities including inhibition of adipogenesis, while in vivo it significantly lowered the levels of triglycerides, glucose and oxidized glutathione.

Effects of various roasting conditions on acrylamide, acrolein, and polycyclic aromatic hydrocarbons content in cocoa bean and the derived chocolates

ABSTRACT The effect of roasting parameters such as the temperature (135 and 150°C) and relative humidity of air (RH of 0.3 and 5.0%) on acrylamide, acrolein, and polycyclic aromatic hydrocarbon (PAH) levels in whole and crushed cocoa beans and chocolates derived from these beans was studied. Acrylamide was identified in all tested samples of roasted cocoa beans, irrespective of process conditions. Its contents in chocolates produced from these beans were similar. The highest acrylamide concentration was found in whole cocoa beans roasted at 135°C and RH of 5.0%. Small amounts of acrolein were present only in the roasted whole cocoa beans while neither the roasted crushed cocoa beans nor chocolates contained this aldehyde. Roasting conditions significantly affected the profile and content of PAHs in whole and crushed cocoa beans and the richest in PAHs were crushed cocoa beans roasted at 150°C and RH of 5.0%. The chocolates obtained in this study contained significantly higher concentrations of PAHs than the roasted cocoa beans used for their production. The results of the study demonstrate that optimization of roasting conditions may reduce levels of all these harmful substances in cocoa beans.

Evaluation of estrogenic activity of red clover (Trifolium pratense L.) sprouts cultivated under different conditions by content of isoflavones, calorimetric study and molecular modelling

Isoflavones have an affinity for estrogen receptors (ERs) including beneficial affinity for ERβ. Widely used soy is a source of poorly absorbed isoflavones glycosides. Red clover contains mostly easily absorbed free aglycones. Red clover sprouts were cultivated under different conditions (white light, UVA or UVB for 12 or 24 h a day at 18 or 25 °C) to maximise the content of isoflavones, especially of high affinity for ERβ. The affinity of isoflavones to ERs was evaluated by molecular modelling and isothermal titration calorimetry (ITC). The richest source of isoflavones, especially formononetin were sprouts cultivated for 10 days under continuous white light and at 25 °C (562 mg/100 g of fresh mass). Formononetin and the above sprouts has been shown to have a high affinity for ERβ. Red clover sprouts can be considered as a source of phytoestrogens with high biological activity and as a dietary supplement reducing menopausal symptoms.

Influence of the Form of Administration of Chlorogenic Acids on Oxidative Stress Induced by High fat Diet in Rats

Green coffee is one of health-promoting supplements of the diet, applied in the form of either preparations or enriched food products. Its positive impact is manifested by mitigation of the development of certain tumors, e.g., in the colon and liver, and type 2 diabetes. Many studies proved that chlorogenic acids are the main active substances in green coffee. The bioavailability of these compounds depends among others on their interactions with other components of the diet, mainly proteins. When they are used as food ingredients, their bioavailability is additionally decreased because of the decomposition or interactions with other ingredients during food processing. The undesirable changes may be limited among others by microencapsulation, for example with β-cyclodextrin. In this study, rats were fed the pro-oxidative high fat diet, which was supplemented with chlorogenic acids from green coffee that were used in four forms such as: a purified extract, complexes of chlorogenic acids and β-cyclodextrin, and bread supplemented with either the extract or the β-cyclodextrin inclusion complex. Chlorogenic acids added to bread because of the reduced absorption from the crumb in the small intestine and increased passage to the colon, contributed to the beneficial modification of enzymatic activities of intestinal microbiota. When added directly to the diet, they contributed to the improved antioxidant status in the liver and kidneys, lowered glucose level and increased HDL level. A high ratio of reduced to oxidized glutathione in the liver and a high concentration of antioxidants in the blood serum were observed after administration of chlorogenic acids in the form of inclusion complexes with β-cyclodextrin, indicating that microencapsulation increased their bioaccessibility due to the limited interactions with other components of the diet.

Identification of Carotenoids and Isoprenoid Quinones from Asaia lannensis and Asaia bogorensis

The aim of the study was to identify and quantitatively assess of carotenoids and isoprenoid quinones biosynthesized by six different strains of acetic acid bacteria, belonging to genus Asaia, that are common beverage-spoiling bacteria in Europe. Bacterial cultures were conducted in a laboratory liquid culture minimal medium with 2% sucrose. Carotenoids and isoprenoid quinones were investigated using UHPLC-DAD-ESI-MS analysis. In general, tested strains of Asaia spp. were able to produce 10 carotenoids and 3 isoprenoid quinones: menaquinone-7, menaquinone-8, and ubiquinone-10. The main identified carotenoids in Asaia lannensis strains were phytofluene, neurosporene, α-carotene, while for Asaia bogorensis, neurosporene, canthaxanthin, and zeaxanthin were noted. What is more, tested Asaia spp. were able to produce myxoxanthophyll, which has so far been identified primarily in cyanobacteria. The results show that A. lannensis are characterized by statistically higher concentrations of produced carotenoids, as well as a greater variety of these compounds. We have noted that carotenoids were not only accumulated by bacterial cells, but also some strains of A. lannensis produced extracellular carotenoids.

Antifungal Activity of Lactobacillus pentosus ŁOCK 0979 in the Presence of Polyols and Galactosyl-Polyols

The antifungal activity of Lactobacillus pentosus ŁOCK 0979 depends both on the culture medium and on the fungal species. In the control medium, the strain exhibited limited antagonistic activity against indicator food-borne molds and yeasts. However, the supplementation of the bacterial culture medium with polyols (erythritol, lactitol, maltitol, mannitol, sorbitol, xylitol) or their galactosyl derivatives (gal-erythritol, gal-sorbitol, gal-xylitol) enhanced the antifungal properties of Lactobacillus pentosus ŁOCK 0979. Its metabolites were identified and quantified by enzymatic methods, HPLC, UHPLC-MS coupled with QuEChERS, and GC-MS. The presence of polyols and gal-polyols significantly affected the acid metabolite profile of the bacterial culture supernatant. In addition, lactitol and mannitol were used by bacteria as alternative carbon sources. A number of compounds with potential antifungal properties were identified, such as phenyllactic acid, hydroxyphenyllactic acid, and benzoic acid. Lactobacillus bacteria cultivated with mannitol synthesized hydroxy-fatty acids, including 2-hydroxy-4-methylpentanoic acid, a well-described antifungal agent. Scanning electron microscopy (SEM) and light microscopy confirmed a strong antifungal effect of L. pentosus ŁOCK 0979.