The Clarifying Reagent, or how to make the analysis of milk and dairy products easier
Difficulties with the analysis of opaque milk and dairy products can be resolved by rendering the sample transparent. This allows direct photometric measurements of the reaction mixtures, and all sample pre-treatment steps become unnecessary. For this, several reagents have been reported in literature. Among them, the ‘Clarifying Reagent’ is mainly described here: its composition is given because it is now released from patenting restrictions. Its main property is a low absorbance between 340 and 800 nm. So it can be used in many chemical and enzymatic colorimetric measurements for estimating the quality of milk and dairy products.
Determination of Sulfhydryl Groups in Milk Using Ellman's Procedure and Clarifying Reagent®
Abstract This work reports on a rapid method for determination of total sulfhydryl groups in raw and heated milks using 5,5'-dithio-bis(2-nitrobenzoic acid). The reaction medium is clarified after the chemical reaction by addition of a dissolving agent; thus, the spectrophotometric measurements are performed directly in milk without other sample treatment. This protocol correlated well with amperometric titrations (r=.994). Results on raw milks from individual cows showed seasonal variations in sulfhydryl groups. Sulfhydryl groups decreased in heated commercial milks. This method is simple, rapid, and easily applicable in routine measurements and may allow heated commercial milks to be distinguished.
Experimental study of thermal modeling for stratospheric platform airships
R&D work on the Japanese stratospheric platform airship is discussed from the viewpoint of the thermal modeling. The work includes two experiments on the thermal characteristics of the 25m-long airship and the 35m-long PV-equipped airship model. The validity of the current thermal model was confirmed by comparing the calculated results with the measured data. The other important work is the Ground-to-Stratosphere (GTS) flight test. A 47mlong airship-shaped balloon was flown to the stratosphere. The flight simulation program into which the thermal model was integrated, was developed and applied successfully to predict the ascent behavior and the flight trajectory.