Flavor Fade in Peanuts During Short-term Storage

ABSTRACT: Flavor characteristics of roasted peanuts over short-term storage were explored through sensory and chemical analyses. The volatiles from freshly roasted peanuts were evaluated over short-time (21 d) storage using gas chromatography, chemosensory techniques, and a sensory panel to quantify and identify pyrazines and hexanal over a 21-d storage period. A significant decrease ( P < 0.05) was noted in 2,3-diethylpyrazine, 2-methoxypyrazine, 2,3-dimethylpyrazine, 2-ethyl-3-methylpyrazine, and 2,3,5-trimethylpyrazine concentrations over a 21-d period. No significant difference ( P > 0.05) was noted in the 2-methylpyrazine and 2-ethylpyrazine concentrations. The hexanal concentration significantly increased ( P < 0.05) over the 21-d period. The peroxide values and sensory analysis agreed with these results. A significant increase ( P < 0.05) in peroxide value was seen at days 14 and 21, and a significant decrease ( P < 0.05) in fresh roasted peanuty flavor from day 0 to 21 and significant increases ( P < 0.05) in painty, cardboardy, and bitter flavors from day 7 to 21 with the sensory analysis. The electronic nose successfully separated day 0 and 21 samples from day 7 and 14 samples, which were also separated but with some overlap.     

Mathematical Relationship Between Surface Emission and Diffusion Coefficients

This naver analvzes the surface emission coefficient corresponding to anv diffusion coefficient expressed as an exponential function of the concentration diffusing substance in capillary porous solids. Theoretical equations for surface emission coefficient for both sorption and desorption are presented. Procedures to derive the diffusion coefficient and to verify the corresponding surface emission coefficient are made using experimental sorption data of aspen (Populur sp.) wood. It is of interest to note that the theoretical models for diffusion and surface emission coefficients can be established and/or evaluated using the same set of experimental dara.     

Trimethylpentanediol dibenzoate: New plasticizer for plastisol screen ink

Trimethylpentane diol (TMPD) dibenzoate use in vinyl as a plasticizer is not well recognized, and little has been published on vinyl performance characteristics. To assess new applications for vinyl, a basic evaluation was conducted. Based on the results of the screen and other considerations an evaluation for utility in plastisol silk screen ink was conducted. The results indicated that the TMPD dibenzoate performed very well in white ink, requiring good fabric dye bleed resistance compared to polymeric and phthalates currently being used for non-bleed ink. Non-bleed characteristics are important for colored tee shirt printing. The benzoate is a good solvator and has excellent extraction resistance.     

Valid parameter range analyses for chemical reaction kinetic models

The present work quantifies the relations between the structure of a chemical reaction kinetic model, its valid parameter range, and the truncation error tolerance of the model. General methods are presented to solve the three important problems of valid parameter range analysis: (1) identification of the valid parameter range of a kinetic model, (2) estimation of the error tolerance required when applying a kinetic model over a specified parameter range, and (3) improvement of existing model generation algorithms to construct more robust models. Finally, the relationship between a model's structure, its valid parameter range, and the truncation error tolerance are illustrated by the flexibility-tolerance-model graph. The new methods are applied to pyrolysis of methane/ethane mixtures.     

Characterization of Dip-Coated Boron Nitride on Silicon Carbide Fibers

Amorphous boron nitride thin coatings (∼0.2 μm) have been formed on Nicalon and C-Nicaion (pre-carbon-coated Nicalon) yarns via dip coating in boric acid solution followed by heating and nitriding in NH₃gas at 1000°C. X-ray photoelectron spectroscopy (XPS) and Auger electron spec-troscopy (AES) studies have shown the formation of boron nitride. The coating was boron rich and contains oxygen. The N/B and O/B ratios range from 0.6 to 0.8 and from 0.1 to 0.25, respectively. Tensile strength measurements revealed that the BN-coated C-Nicalon yarn maintained ∼85% of its original strength while BN-coated Nicalon lost ∼85% of its original strength. Auger depth profiles showed that there was a consumption of carbon during the heating and nitridation process for both BN-coated Nicalon and C-Nicalon fibers. However, the depletion of carbon in BN-coated Nicalon fibers was much more severe than that in BN-coated C-Nicalon fibers.     

A System for Three-Dimensional Interactive Simulation of Hand Biomechanics

A real-time interactive graphics simulation of the mechanics of the human thumb has been developed. The simulation utilizes a realistic data structure for the bones of the thumb which may be expanded to include the hand and forearm. This is coupled to a model of the kinematics of the joints in a concurrent processing arrangement in which the dynamic graphical transformations for scaling, translation, rotation, perspective, and clipping are all performed on a special-purpose display processor. The model and the control functions are distributed between this processor and a separate general-purpose superminicomputer. The resulting system presents the user with a realistic simulation of the movements of the thumb in normal and impaired states. The user may choose from a menu of options, including an interactive tendon transfer simulation for the current hand being simulated. He may control (interactively and in real time) the view, observation position, skeletal motion, and parameters for use in the model of joint mechanics. This type of computer modeling, utilizing a realistic three-dimensional data structure, models of musculoskeletal kinematics, and interactive programming, shows great potential for bringing mathematical modeling into useful clinical, research, and educational applications.