Controlled hydrolysis of cheese whey proteins using trypsin and α-chymotrypsin

This study examined the production of protein hydrolysates with controlled composition from cheese whey proteins. Cheese whey was characterized and several hydrolysis experiments were made using whey proteins and purified β-lactoglobulin, assubstrates, and trypsin and α-chymotrypsin, as catalysts, at two tem peratures and several enzyme concentrations. Maximum degrees of hydrolysis obtained experimentally were compared to the theoretical values and peptide compositions were calculated. For trypsin, 100% of yield was achieved; for α-chymotrypsin, hydrolysis seemed to be dependent on the oligopeptide size. The results showed that the two proteases could hydrolyze β-lactoglobulin. Trypsin and α-chymotrypsin were stable at 40°C, but a sharp decrease in the protease activity was observed at 55°C.     

Homogeneous Linewidth and Saturation Parameter of Infrared Laser Transitions

We investigated the behavior of infrared (IR) absorption laser transitions of methanol isotopes in the presence of an uniform electric field, in order to determine Doppler-free spectroscopic data such as homogeneous linewidth and saturation parameter. For this we combine photoacoustic detection with the high resolution provided by the Nonlinear Hanle Effect (NLHE) on molecular transitions.     

Simple model of compound waveguide structures used as fiber-optic sensors

In this work we present an application of a simple quasi-geometrical model to analyze the behavior of compound waveguide structures used as fiber-optic sensors. This theoretical model is based on the adjustment of the parameters of the structure from the experimental measures to predict the observed behavior of the device. It also takes into account the non-monocromaticity of the used source. In this way, it can be used as a design criterion for this kind of structures. It is applied to a refractive index fiber-optic sensor based on the excitation of surface plasmon in a metal layer by the light guided by a monomode fiber.     

2‐(4‐Methoxyphenyl­azo)‐4‐phenyl­phenol

The crystal structure of the title compound, C₁₉H₁₆N₂O₂, displays a trans configuration of the azo moiety, which forms an intramolecular O—H?N=N hydrogen bond. The H?N and O?N distances are 1.81 (3) and 2.581 (4) Å, respectively. The azo­benzene moiety is approximately planar, and has a dihedral angle of ca 23° with the substituted phenyl group.     

Brazilian integrated sugarcane-soybean biorefinery: Trends and opportunities

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Compounds from the Root Bark of Bowdichia virgilioides

Chemistry of Natural Compounds -