Marek Sikora

Sauces and Dressings: A Review of Properties and Applications

This comprehensive review of sauces and salad dressings covers the literature over the last decade with respect to physical and chemical properties and the applications of these products. As such, texturizing and structural systems (especially hydrocolloids) are described in detail and the application of polysaccharide thickeners as texture providers is described. Microbiological aspects of sauces are covered with relevant sections discussing the factors affecting microbiological activity and microbial spoilage and/or enhancement of a range of sauces. In addition, the use of carbohydrates and proteins as emulsifiers in many sauces is described. Quality aspects are given prominence in this review with sections being devoted to rheological and textural properties, chromatographic approaches and sensory aspects. Healthy sauces such as those having low sodium, reduced fat and cholesterol or containing inulin or microcrystalline cellulose are reviewed. Finally, for various sections the trends of the main findings as well as suggestions for future research are presented.

Quality of gluten-free supplemented cakes and biscuits

Gluten-free confectionery products were used as controls for comparison with the products, which included different supplements such as linseed meal, amaranth and/or buckwheat. The latter were expected to increase nutritional values of confectionery products. Cookies were analyzed in terms of volume, selected textural parameters (hardness, cohesiveness), organoleptic quality, shelf-life, and different chemical components. All supplemented gluten-free products received high consumer scores, exceeding in some cases those of control samples. Supplementation of gluten-free confectionery products with linseed meal, amaranth and/or buckwheat flours enhanced their final nutritional quality. A significant rise was observed in the protein content and dietary fiber, and in the case of linseed meal also α-linolenic acid. All of the supplemented gluten-free confectionery products contained more macro-elements and micro-elements (i.e. potassium, phosphorus, magnesium, calcium, iron, manganese, zinc and copper), as compared with the controls. Taking into account the amino-acid composition, amaranth proved a more beneficial supplement of gluten-free products than linseed.

Probing the crystalline environment of α-alumina via luminescence of metal ion impurities: an optical method of ceramic flaw detection

Abstract Optical studies of UV-excited, polycrystalline α-alumina were performed as a function of the sintering temperature. The luminscence intensity in the 600–750 nm region increased with alumina density and originated from trace amounts of Cr 3+ impurities residing in two different sites, labeled A and B. Since trace amounts of Cr 3+ exist in most aluminas that are used in commercial applications, this luminescent methodology has promise as a simple, nondestructive tool for detecting packing-density-gradients and microcracks in alumina-based ceramics at different stages of shape-forming and sintering. In high-density alumina, at T =300 K, sites A emit sharp R 1 / R 2 -lines at 14407.5/14436.5 cm −1 with Δ E ( R 2 − R 1 ) splitting of ∼30 cm −1 , indicating a ruby-like high-field crystalline environment. The lower symmetry sites (B) are characterized by higher-energy, presumably 2 E→ 4 A 2 doublet transitions (at 14746.7 cm −1 and ∼14818 cm −1 ) and 2 E splitting of ∼71 cm −1 . The larger splitting is attributed to anisotropy in the electron repulsion energy for Cr 3+ ions residing in slightly larger volumes of the CrO 6 and/or due to tetragonal crystal symmetry distortion. Luminescence from B sites is revealed for the first time; excitation using an argon-ion laser at 514.5 nm only reveals luminescence from A sites. UV-excited, luminescence based density calibration curves and density-dependent, color images of alumina samples, along with methodologies for density gradient mapping and microcrack detection, are described. It is shown that density gradients and microcracks can be visualized either by imaging the inherent luminescence of α-alumina or by fluorescence from an appropriate staining dye.

Thixotropic properties of normal potato starch depending on the degree of the granules pasting

The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).

Kinetics of gelatinization of potato starch studied by non-isothermal DSC

The kinetics of gelatinization of potato starch (starch:water weight ratio, 1:1) were investigated using differential scanning calorimetry (DSC). In the first stage, two isoconversional (Ozawa-Flynn-Wall and Friedman) methods were applied. It was found that the value of the activation energy (E) changes with 0 < α < 1 from approximately 75 to 138 kJ/mol. Further analysis using non-linear regression methods revealed that the best fit was found for a competitive double-step reaction, whereby the first step was attributed to the “n-order reaction” scheme and the second step was described by three-dimensional diffusion of Janders type. The first step was attributed to the gradual formation of interchain and intrachain hydrogen bonding which restricts chain mobility and led at elevated temperature to the second diffusion-based ratelimiting step. For this model function, a spherical shape for the reacting bodies is the best stereogeometrical approximation; this corresponds well with observations concerning starch alignment at different microstructural levels and its behaviour during gelatinization.

Dextrin plasticizers for aqueous colloidal processing of alumina

Abstract Rheological experiments were conducted to investigate the applicability of dextrins as plasticizers for the aqueous, colloidal processing of alumina ceramics. Upon the addition of 1–10 wt.% of dextrins, aqueous suspensions of 20 vol.% α-alumina exhibited a transition from strongly-flocculated, pseudoplastic behavior to a low-viscosity, Newtonian-like state. We evaluated rheological properties as a function of a range of polysaccharide molecular weights between 900 and 63 000 Daltons. Dextrins of molecular weight between 6450 and 15,000 Daltons were the most effective from the standpoint of cost and rheological performance.

Protein plasticizers for aqueous suspensions of micrometric- and nanometric-alumina powder

Ovoalbumin and its hydrolysate were developed as economical and environmental friendly plasticizers for the production of engineering ceramics from micrometric- and nanometric-sized powders. These proteins are feasible as replacements for commonly used petrochemicals that suffer from problems of toxicity, volatility, flammability, and high cost. A key advantage to protein-based additives is that they are available from inexpensive plant and animal sources (e.g. waste products such as slaughterhouse blood, by-products from meat and plant production). Aqueous alumina suspensions and high-density aqueous alumina pastes were blended with such proteins to form green bodies that were easily moldable and could be sintered to full density without cracking. The application of proteins provides thermally induced gelation of aqueous alumina suspensions.

Thallium(I) starchate

Thallium(I) starchates of various degrees of substitution were prepared from potato, corn and hydrogen starch by reaction with either thallium(I) hydroxide or with thallium ethanolate. After thallation, hydrogen and potato starch exhibited typical characteristics of gelation whereas that of corn starch did not. The chemical structure of the products was investigated using X-ray photoelectron spectroscopy. Potato starch was thallated and contained chemically bound thallium whereas corn starch formed complexes with thallium(I) hydroxide and ethoxide.

Cocoa agronomy, quality, nutritional, and health aspects.

The history of cocoa and chocolate including the birth and the expansion of the chocolate industry was described. Recent developments in the industry and cocoa economy were briefly depicted. An overview of the classification of cacao as well as studies on phenotypic and genetic diversity was presented. Cocoa agronomic practices including traditional and modern propagation techniques were reviewed. Nutrition-related health benefits derived from cocoa consumption were listed and widely reviewed. The specific action of cocoa antioxidants was compared to those of teas and wines. Effects of adding milk to chocolate and chocolate drinks versus bioavailability of cocoa polyphenols were discussed. Finally, flavor, sensory, microbiological, and toxicological aspects of cocoa consumption were presented.

Use of Modified Starches as Thickeners of Cocoa Syrups

Elaboration of cocoa syrups by the use of modified starches such as acetylated distarch adipate (ADA) and oxidised starch (OS) were described and analysed the influence of different amounts of ADA and OS on physical and sensory properties of cocoa syrups. The sensory, textural and rheological properties of syrups produced in the laboratory conditions were compared to the properties of commercially produced ones. The quantity of modified starch added affected textural and rheological properties of syrups. All analysed syrups showed non-Newtonian, pseudoplastic flow and thixotropy. Values of yield stresses, viscosities of Casson, and consistency coefficients of syrups prepared in laboratory conditions increased with an increase in the addition of modified starches.