Physicochemical and sensory quality of several commercial Brazilian chocolate milk beverages

Five brands of Brazilian chocolate milk were subjected to physicochemical and acceptability analysis. The moisture content, fat content, pH and soluble solids content varied between 78.35 and 84.27 g/100 mL, 1.68 and 3.08 g/100 mL, 7.11 and 7.44, 14.0 and 19.0° Brix, respectively, while the ash contents and % lactic acid equivalents were similar. Four of the tested brands had acceptable scores in all attributes; however, one had lower acceptability scores and lower values for luminosity, chromaticity, b* and hue angle, which are potential indicators of the sensory quality. Strong chocolate aroma, strong chocolate flavour, strong brown colour, brightness and sandiness may be used as indicators of low acceptability for chocolate milk.     

The Impact of Polyoxyethylene Sorbitan Surfactants in the Microstructure and Rheological Behaviour of Emulsions Made With Melted Fat From Cupuassu (<Emphasis Type="Italic">Theobroma grandiflorum</Emphasis>)

Cupuassu fat is a good candidate for partial substitution of cocoa butter in many products, including emulsions. However, for such use it is necessary to know the characteristics of the products prepared with cupuassu fat. Therefore, the main goal of this work is to characterize emulsions prepared with cupuassu fat using the surfactants Tween^® 60, Tween^® 80 and Tween^® 85 as emulsifiers. The emulsions were prepared at 43 °C with addition of 0.5 or 1.5 % (w/v) of surfactant and compared with an emulsion without surfactant. All emulsions were analysed by conductivity, stability, pH, optical microscopy, rheology and oxidative stability. It was verified that the emulsions prepared with Tween^® 60 and Tween^® 80 have higher stability, smaller droplet size and higher apparent viscosity. Also, these properties are positively influenced by the concentration of the surfactant. On the other hand, emulsions prepared with Tween 85 or without surfactant reached unsatisfactory results. The rheological behaviour of the emulsions was adequately described by both Herschel-Bulkley and Mizhari-Berki models revealing pseudoplastic character. These emulsions also present strong gel behaviour, with storage modulus higher than loss modulus. In conclusion, cupuassu fat can be used as oil phase for emulsions products and this characterization helps to understand their behaviour in order to increase their use in food industry.     

Profiling of the Bacterial Microbiota along the Murine Alimentary Tract

Here, the spatial distribution of the bacterial flora along the murine alimentary tract was evaluated using high throughput sequencing in wild-type and Tff3-deficient (Tff3^KO) animals. Loss of Tff3 was linked to increased dextran sodium sulfate-induced colitis. This systematic study shows the results of 13 different regions from the esophagus to the rectum. The number of bacterial species (richness) increased from the esophagus to the rectum, from 50 to 200, respectively. Additionally, the bacterial community structure changed continuously; the highest changes were between the upper/middle and lower gastrointestinal compartments when comparing adjacent regions. Lactobacillus was the major colonizer in the upper/middle gastrointestinal tract, especially in the esophagus and stomach. From the caecum, a drastic diminution of Lactobacillus occurred, while members of Lachnospiraceae significantly increased. A significant change occurred in the bacterial community between the ascending and the transverse colon with Bacteroidetes being the major colonizers with relative constant abundance until the rectum. Interestingly, wild-type and Tff3^KO animals did not show significant differences in their bacterial communities, suggesting that Tff3 is not involved in alterations of intraluminal or adhesive microbiota but is obviously important for mucosal protection, e.g., of the sensitive stem cells in the colonic crypts probably by a mucus plume.     

SMART-Reactors: Tailoring Gas Holdup Distribution by Additively Manufactured Lattice Structures

In chemical process engineering, fast gas-liquid reactions often suffer from an inefficient distribution of gas and therefore mixing and mass transfer performance. This study deals with the possibility of influencing the local gas holdup and bubble size distribution in a gas-liquid process using additively manufactured lattice structures (AMLS). The used measuring technique to study bubble size, velocity, and the local gas holdup is a photo-optical needle probe. By using AMLS, a significant radial homogenization of the local gas holdup and the mean bubble size is achieved. Furthermore, it can be demonstrated that the bubble size can be tailored by the geometry of the inserted structure. It is illustrated that the mean bubble velocities are lowered within the lattice resulting in a higher residence time of the dispersed phase with an impact on the mass transfer performance within the AMLS.     

Transition and flow boiling heat transfer inside a horizontal tube

Experiments on transition and flow boiling heat transfer with refrigerant R114 inside a horizontal tube were performed at bubble flow, critical heat flux and in the transition region between bubble flow and film boiling at mass fluxes between 1200 and 4000 kg/m² s and in the pressure range between 5 and 15 bar. In comparison with pool boiling bubble flow heat transfer depends essentially on the mass flow rates and on the vapor quality. The critical heat flux depends less on the temperature difference than in pool boiling heat transfer and exhibits a maximal and a minimal value as a function of the pressure. The critical heat flux increases with mass flow rate as already shown by Collier. In the region of transition boiling the heat flux over the difference between wall and saturation temperature approaches a horizontal curve. Therefore in this region an evaporator may always be operated under stable conditions and burn out does not occur.     

The Effect of processing on the content and composition of free sterols and sterol esters in soybean oil

The content and composition of free sterols and sterol esters in crude soybean oil and in oils from different stages of two continuous refining systems were determined. The sterols were isolated by preparative thin layer chromatography and analyzed by gas chromatography with cholesterol as an internal standard. The free sterols in one of the degummed oils amounted to 3.1 mg/g and were diminished to 1.8 mg/g oil by the De Laval Short-Mix refining process. The content of free sterols of the other degummed oil was reduced from 3.4 to 1.6 mg/g oil by the Zenith process. The greatest reduction of sterol content was caused by the treatment with bleaching earth. The sterol esters accounted for 0.6 mg/g of the degummed oil, and only very small changes were observed during the processes. However, changes in the composition of fatty acids of the sterol esters were found. These changes might indicate a selective deacylation of sterol esters or an interesterification during the refining processes. The composition of sterols in free and esterified form were different. Campesterol, stigmasterol and sitosterol were obtained in both free and esterified form, but Δ7 stigmasterol was only found in esterified form. Only small changes in the percentage distribution of the sterols occurred during the processes. Present adress Food Technology Division, ALFA-LAVAL,S-14700 Tumba, Sweden     

Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. IX. Alkylierungen mit 2,2,4-Trimethylpentan (Isooctan)

Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. IX. Alkylations with 2,2,4-Trimethylpentane (Isooctane) The non-conventional alkylation of benzene, toluene, ethyl- and isopropylbenzene, fluoro- and chlorobenzene with 2,2,4-trimethylpentane in the presence of acid catalysts is described. The composition of the rather complex reaction mixtures is determined by gas-liquid chromatography and mass spectrometry, tert. butylarenes being the main products beside alkylsubstituted indanes and tetralines. Their formation is interpreted as a competition between fragmentation and isomerization of the alkylating agent. By use of trifluoromethanesulfonic acid or combinations of catalysts from HF or HSO₃F with variant metallic fluorides at lower temperatures the selectivity of the reaction may be partially raised.