Changes in aroma and sensory profile of food ingredients smoked in the presence of a zeolite filter

During smoking, formation of desirable smoky compounds and carcinogenic polycyclic aromatic hydrocarbons (PAH) are inextricably linked. We have previously developed a zeolite filter technology (PureSmoke Technology or PST) that reduces the PAH content of a smoke stream, particularly reducing the concentration of benzo[a]pyrene, a known carcinogen, by up to 93%. The aim of this work was to determine whether there were changes in the volatile and sensory profiles of ingredients smoked using PST compared to the traditional smoking process (Trad). Smoked tomato flakes (either PST or Trad) were added to either low-fat or full-fat cream cheese for sensory profiling and consumer preference tests, and volatile analysis was carried out using solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The sensory analysis showed a significant decrease (p < 0.01) in bitterness when the PST was employed and a significant decrease in overall smoky aroma and flavor (p < 0.001), which resulted in an increase in the perception of cheesy aroma and flavor. This was consistent with a decrease in many of the smoky aroma compounds, particularly the guaiacols. However, consumer preference tests showed that there was no adverse effect on the flavor of the products, and there was even a tendency for the PST product to be preferred to the Trad product (p = 0.096). The smoke compounds were quantitated and compared in smoked tomato paste. Odor activity values (OAVs) calculated from the literature thresholds suggested that guaiacol and 4-alk(en)yl-substituted guaiacols are likely to be among the most highly odor-active compounds in these smoked ingredients

Residual Stress Measurements Inside a Small Inner Diameter Hole at Low Bragg Angle Using X-Ray Diffraction Technique

Abstract. A new X-Ray diffraction (XRD) goniometer has been specially developed to nondestructively measure residual stress (RS) on the inner diameter (ID) of small holes in metal and ceramic components. The major advantage of this novel goniometer is its ability to perform RS measurements on the ID of small holes without the need to section the component, thus maintaining the integrity of the residual stress field inherent to the component of interest. This new patented XRD goniometer has been used on a wide variety of aerospace components on features such as holes in airframe/structural components, as well as fastener/bolt holes, air holes, and confined areas on rotating and non-rotating turbine engine components. In many instances, measurements can be performed at 2θ angles much lower than the widely accepted lower limit of approximately 130°. The selection of the actual Bragg angle used depends upon the material itself, the hole ID, and the thickness of the component. Results obtained indicate that the new goniometer can be used to measure RS on the ID of small holes with good accuracy and precision even at relatively low 2θ angles in the vicinity of 100°

Residual stress in turbine disk materials, effect of low cycle fatigue

Les disques de turbo-réacteur fonctionnent à haute température et chargements élevés. Ils sont soumis à des déformations thermiques et mécaniques. Les contraintes résiduelles de compression sont introduites en surface par grenaillage. Durant le service, les contraintes appliquées sont réduite jusqu'à zéro ou passent en tension, cela est causé par la fatigue oligocyclique. La base de données FMA des contraintes résiduelles dans les disques en fonction du nombre de cycles, mise en place par FMA-PROTO, a montré une tendance linéaire. La pente de la droite dépend de la sévérité des conditions de fatigue et de service cumulés. Les courbes de Wöhler obtenues en flexion rotative ont montré une augmentation de la durée de vie pour les échantillons grenaillés pour les chargements appliqués faibles et aucun bénéfice pour les chargements appliqués élevés,Aircraft turbine engine disks operate at high cyclic loads. Thermal strain and mechanical strain are applied. Compressive residual stresses are introduced to the surface by shot peening. Applied stresses, when they accumulate cycles above yield will gradually cause the surface compressive residual stress to be reduced until the surface becomes residually stressed to zero or in tension. The FMA database of disk residual stress measurements versus cycles accumulated by PROTO-FMA on turbine disks has shown a general linear trend. The slope of the linear fit depends on the severity of the cumulative service conditions. The S/N curves obtained from rotating beam testing showed extended lifetime on shot peened specimens at lower applied loads and no benefit at higher loads because of the surface condition

Comparison of Residual Stress Measurement Techniques and Implementation Using X-Ray Diffraction

Abstract. Regardless of the particular residual stress (RS) measurement technique being used, all are based on the same basic principles when using x-ray diffraction (XRD). Every technique has both its advantages and disadvantages, many of which are well known to engineers and scientists however, some of the important &quot;finer points&quot; are unfortunately not widely discussed or known by those not well versed in the subject. This paper will try to bring to light many of these commonly misunderstood issues by comparing the different techniques and attempt to illuminate the associated problems a user may encounter when measurements become challenging i.e. when RS measurements are to be performed in tight grooves or on textured materials for example. In this study, different techniques including the: Cosα technique, MET (used in Psi, Omega, or Modified Psi mode) have been evaluated and tested on a variety of materials and geometries. Introduction RS measurements using XRD techniques were first performed as early as 1925 In this study, different techniques including the: Cosα technique, MET (used in Psi, Omega, or Modified Psi mode) will be evaluated and tested on a variety of materials and geometries. This paper will emphasize the different findings and the limitations associated with each of the techniques evaluated

Impact of protein, lipid and carbohydrate on the headspace delivery of volatile compounds from hydrating powders

The release of volatile compounds, such as aroma, from a food material during hydration is of wide relevance to the food industry. To this end, dry powders of varying chemical composition were hydrated in a controlled system to investigate the impact of varying composition (protein, lipid and carbohydrate) on the delivery rate of volatile compounds to the headspace. Additional lipid and carbohydrate reduced the concentration of volatile compounds in the headspace and accelerated their rate of delivery to the headspace. Protein had no measurable impact. Of the volatile compounds measured, 2,3 butanedione and acetaldehyde were shown to be released slowly into the headspace, and pyrrol, methyl acetate and pyridine were released rapidly; this differential release rate was strongly correlated with hydrophobicity and would indicate that during hydration there is a temporal dimension to the relative abundance of volatile compounds in the headspace

Guidelines for the Application of Bonded Repairs to Structures Damaged by Stress Corrosion Cracking

Peer reviewed: YesNRC publication: Ye

Development of bonded repair guidelines for the repair of stress corrosion cracking using residual stress measurement techniques

Peer reviewed: YesNRC publication: Ye