Linalool contents as characteristic of some flavor grade cocoas

Summary The terpenes present in cocoa flavour were analysed by means of gas chromatography-mass spectrometry. The pyranoid linalool oxides, ocimene and nerolidol, were identified for the first time as cocoa volatiles. Linalool, which is the major terpene component in cocoa contributes markedly to the flowery and tea-like flavour of some cocoa varieties. Flavour grade beans contain relatively high concentrations of linalool and basic grade cocoas possess. The isolation of linalool by means of intensive (simultaneous distillation extraction) and more gentle methods (vacuum condensation) yields similar quantitative results. The estimation of the concentration ratio of linalool/benzaldehyde within steam distillates ist suitable for the industrial quality control of unroasted cocoas.

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Linaloolgehalt als Merkmal einiger Edelkakaos

Zusammenfassung In Kakaoaroma wurden anhand GC/MS einige Terpene nachgewiesen, darunter erstmals auch die pyranoiden Linalooloxide, Ocimen und Nerolidol. Linalool als Hauptkomponente dieser Gruppe trägt wesentlich zum blumigen und tee-artigen Aroma einiger Kakaosorten bei. Edelkakaos weisen relativ hohe, Konsumkakaos niedrige Linalool-Konzentrationen auf. Die Isolierung von Linalool unter drastischen (simultane Destillation Extraktion) und milden Bedingungen (Vakuum-Kondensation) liefert ähnliche quantitative Ergebnisse. Die Bestimmung des Konzentrationsverhältnisses von Linalool/Benzaldehyd in Wasserdampfdestillaten eignet sich zur industriellen Qualitätskontrolle von Rohkakao.

     

Thickening of molten white chocolates during storage

When white chocolates are kept molten in storage tanks, problems can arise due to uncontrolled thickening and solidifying of the chocolate mass. The thickening of molten white chocolate was simulated on a laboratory scale using a rotational rheometer under static conditions, interrupted by short shear periods to measure the increasing viscosity. Several chocolates having different dairy components and fat contents were investigated for their tendency to thicken. In addition, sorption isotherms for white chocolates were obtained using dynamic vapour sorption at different temperatures. The sorption isotherms showed the presence of amorphous lactose in all the chocolates that were manufactured from milk powders. Moisture that is released during the crystallization of amorphous lactose causes stickiness and agglomeration of the neighbouring particles and starts the thickening process. This process is highly temperature-dependent. On elevating the temperature the lactose crystallization occurs at lower relative humidities. In order to reduce the tendency of white chocolate to thicken, a high free-fat level should be maintained, based on a high total fat content and on the use of high free-fat milk powders, preferably roller-dried whole milk powders or the combination of skimmed milk powder and anhydrous milk fat.     

Buchbesprechungen

Ohne Zusammenfassung     

Potenzial des IR Micro‐Imaging zur In‐situ‐Untersuchung chemischer Reaktionen in nanoporösen Katalysatoren

The in‐situ study of chemical reactions is an intensively studied research topic. A suitable method for this investigation is the IR micro‐imaging technique, which allows to record space‐ and time‐resolved IR spectra. The preparation of a suitable model system with a 3D pore system for the in‐situ recording of concentration profiles using IR micro‐imaging is described, enabling the space‐ and time‐resolved monitoring of catalytic reactions in nanoporous catalysts for the first time. The model system consists of a nanoporous glass monolith with gas‐tight sealed outer surface, therefore, enabling the recording of concentration profiles of cyclohexane and cyclohexane‐benzene mixtures as a function of time.     

Experiences with primary fascia closure of the abdomen in gastroschisis--a 16 year review

47 children with gastroschisis were operated at the Hannover Medical School between 1980 and 1995. The average gestation period was the 36th week of pregnancy with an average birthweight of 2370 gr. A primary layered closure of the abdominal wall was performed on 46 children. A multi-sided closure of the abdominal wall defect using Gore-Tex was necessary in only one case. Post-operative intubation lasted for an average of 56 hours. The children were fed by parenteral nutrition for an average of 32 days, with oral feeding starting on the 15th post-operative day. The average weight on discharge was 3035 gr. 18% of the children had post-operative problems such as sepsis, necrotic enterocolitis and ileus. A death rate of only 2% is proof of the progress that has been made in prenatal care of the newborn child suffering from gastroschisis and suggests that primary closure of the abdomen is the operative method to be aimed for.     

Semantic failure [of software]

The author offers the opinion that the adoption of the terminology of hardware reliability in the context of software was a terrible, probably unavoidable, and perhaps even necessary, mistake: terrible-because the words cannot have the same meanings in both contexts; and unavoidable-because today there are few systems whose reliability can be assessed without dealing with both