Diacetyl and other Alpha-Dicarbonyl compounds with special reference to the flavor of butter

Diacetyl is an important flavor contributor of butter and various other foods. Similarity in chemical structure suggests that a number of other a-diketones would be similar in certain properties, including odor, to diacetyl, the simplest member of the series. Diacetyl and various homologs were synthesized long ago their reactions studied and certain similar chemical behaviors noted. However, the descriptions of the odors originally given would hardly suggest that diacetyl is involved in the flavor of certain foods. The work of van Niel, Kluyver and Derx (81) showed the importance of diacetyl as a flavor contributor of butter. Epstein and Harris (22-25) patented the use of certain a-diketones as flavoring materials for various foods. Taufel and Thaler (74) incidentally mentioned that in practice acetylpropionyl was sometimes used as a substitute for diacetyl

Ceramic matrix composite turbine engine vane

A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The spar has a first chamber essentially along the suction side and a second chamber along the pressure side opposite the first chamber

Evaluation of the Quality Characteristics of Premium Pork Loins

The objective of this study was to determine shear force, pH, marbling, color characteristics, percentage of intramuscular fat, and purge loss of pork loins from various premium brands in comparison to commodity products. Pork loins (n = 30/brand; Institutional Meat Purchasing Specifications #414) from five premium (PRE A, B, C, D, and E) and two commodity brands (COM A and B) were purchased from food service purveyors and commercial abattoirs. Loins were transported to the Kansas State University Meat Laboratory, Manhattan, KS, and allowed to age 14 to 15 days under refrigerated conditions (36 to 39°F) before fabrication. All PRE brands were similar (P \u3e 0.05) with lesser (P \u3c 0.05) slice shear force values than COM A, with the exception of PRE C, which had greater (P \u3c 0.05) slice shear force values than all other brands evaluated. Similar results were found for Warner-Bratzler shear force, with PRE C having greater (P \u3c 0.05) Warner-Bratzler shear force values than all other treatments, and no difference (P \u3e 0.05) found among the other PRE products. Commodity A was also tougher (P \u3c 0.05) than all PRE brands, except PRE C for Warner-Bratzler shear force. For subjective loin color evaluations, all PRE brands were similar (P \u3e 0.05), with only PRE C having a greater (P \u3c 0.05) color score than PRE B. Commodity B had a lesser (P \u3c 0.05) loin subjective color than all PRE products except PRE B and D. Also, COM B had a greater (P \u3c 0.05) L* value (lighter) and lesser (P \u3c 0.05) a* value (less red) than all of the other brands. No difference (P \u3e 0.05) in a* was found among the PRE brands and only PRE D and E differed (P \u3c 0.05) for L*. The two COM products had a similar (P \u3e 0.05) chop color score, however COM B was lighter (P \u3c 0.05) than all PRE brands. Premium A and E had greater loin visual marbling than all other brands, with no difference (P \u3e 0.05) found among the two COM brands and the other 3 PRE brands. However, for chop visual marbling, the two COM brands had less (P \u3c 0.05) marbling than all PRE brands, except PRE B and C. For fat percentage, all brands had between 2 to 3% fat, with COM A having less (P \u3c 0.05) fat than all PRE brands other than PRE B and D. Little variation was found among brands for pH, but COM B had a lower (P \u3c 0.05) pH than all of the other brands. Premium A, C, and D had less (P \u3c 0.05) weight lost as purge than any of the other brands. The differences observed within the quality traits evaluated show variation among different premium pork loin brands. This provides evidence that consumers and retailers will receive different levels of pork quality and eating satisfaction dependent upon the premium brand purchased

Differential expression analysis with global network adjustment

<p>Background: Large-scale chromosomal deletions or other non-specific perturbations of the transcriptome can alter the expression of hundreds or thousands of genes, and it is of biological interest to understand which genes are most profoundly affected. We present a method for predicting a gene’s expression as a function of other genes thereby accounting for the effect of transcriptional regulation that confounds the identification of genes differentially expressed relative to a regulatory network. The challenge in constructing such models is that the number of possible regulator transcripts within a global network is on the order of thousands, and the number of biological samples is typically on the order of 10. Nevertheless, there are large gene expression databases that can be used to construct networks that could be helpful in modeling transcriptional regulation in smaller experiments.</p> <p>Results: We demonstrate a type of penalized regression model that can be estimated from large gene expression databases, and then applied to smaller experiments. The ridge parameter is selected by minimizing the cross-validation error of the predictions in the independent out-sample. This tends to increase the model stability and leads to a much greater degree of parameter shrinkage, but the resulting biased estimation is mitigated by a second round of regression. Nevertheless, the proposed computationally efficient “over-shrinkage” method outperforms previously used LASSO-based techniques. In two independent datasets, we find that the median proportion of explained variability in expression is approximately 25%, and this results in a substantial increase in the signal-to-noise ratio allowing more powerful inferences on differential gene expression leading to biologically intuitive findings. We also show that a large proportion of gene dependencies are conditional on the biological state, which would be impossible with standard differential expression methods.</p> <p>Conclusions: By adjusting for the effects of the global network on individual genes, both the sensitivity and reliability of differential expression measures are greatly improved.</p&gt

Differential Forms on Log Canonical Spaces

The present paper is concerned with differential forms on log canonical varieties. It is shown that any p-form defined on the smooth locus of a variety with canonical or klt singularities extends regularly to any resolution of singularities. In fact, a much more general theorem for log canonical pairs is established. The proof relies on vanishing theorems for log canonical varieties and on methods of the minimal model program. In addition, a theory of differential forms on dlt pairs is developed. It is shown that many of the fundamental theorems and techniques known for sheaves of logarithmic differentials on smooth varieties also hold in the dlt setting. Immediate applications include the existence of a pull-back map for reflexive differentials, generalisations of Bogomolov-Sommese type vanishing results, and a positive answer to the Lipman-Zariski conjecture for klt spaces.Comment: 72 pages, 6 figures. A shortened version of this paper has appeared in Publications math\'ematiques de l'IH\'ES. The final publication is available at http://www.springerlink.co

Effect of Degree of Doneness, Quality Grade, and Time on Instrumental Color Readings from Beef Strip Loin Steaks Cooked to Six Degrees of Doneness

Objective: The objective of this study was to determine the effect of quality grade and time after cooking on the instrumental color of steaks cooked to varying degrees of doneness. Study Description: Beef strip loins (n = 24) from 12 animals representing five quality treatments [Prime, Top Choice, Low Choice, Select, Select Enhanced (108%)] were collected. Each steak was cooked to a peak internal temperature of very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Each cooked steak was cut in half, perpendicular to the long axis of the steak, and lightness (L*), redness (a*), and yellowness (b*) was evaluated on the internal face of the medial side at 0, 1, 2, 3, 6, 9, and 12 minutes post-cutting using a Hunter Lab Miniscan spectrophotometer. The Bottom Line: The impact of time on internal cooked color was dependent on degree of doneness, with steaks cooked to lower degrees of doneness becoming lighter and more red in color with time and steaks cooked to higher degrees of doneness becoming darker. Additionally, quality treatment had no impact on cooked color measures of non-enhanced steaks. These results provide insight into cooked beef color changes related to time and how this might impact degree of doneness perceptions by consumers

Visual Degree of Doneness Has an Impact on Palatability Ratings of Consumers Who Had Differing Degree of Doneness Preferences

Objective: The objective of this study was to determine the impact of feeding consumers of varying degree of doneness preferences steaks cooked to multiple degrees of doneness on their perceptions of beef palatability. Study Description: Paired Low Choice frozen steaks from the posterior half of the strip loin were randomly assigned a degree of doneness of rare (140°F), medium-rare (145°F), medium (160°F), medium-well (165°F), or well-done (170°F). Consumer panelists, prescreened to participate in panels based on their degree of doneness preference, were served steak samples cooked to each of the five degrees of doneness under low-intensity red incandescent lighting to mask any degree of doneness differences among samples. Next, consumers were served steak samples under white incandescent lighting, with white fluorescent background lighting. Pre-screening consumers for degree of doneness preference allowed for a measure of the impact of “missing” the consumer’s ideal degree of doneness and quantification of the impact of both undercooking and overcooking steaks on consumer beef palatability ratings. The Bottom Line: When steaks are overcooked, palatability ratings decrease; however, undercooking has a positive effect on palatability perception regardless of the consumer’s degree of doneness preference

Consumer Juiciness Acceptability Supports the Beef Marbling Insurance Theory

Objective: The objective of this study was to determine whether increased marbling reduces the negative impact that increased degree of doneness has on consumer palatability scores. Study Description: Beef strip loins were collected to represent five quality treatments [Prime, Top choice, Low choice, Select, and Select enhanced; n = 12 pairs/quality grade] and fabricated to 1-in steaks. Steaks were cooked to one of six degrees of doneness: very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Consumers (n = 360) rated each steak for juiciness, tenderness, flavor, and overall liking on 100 The Bottom Line: Marbling could play a role in compensating for the negative effects of advanced degrees of doneness on juiciness acceptability, providing insight into the quality grade needed for consumers to be satisfied with juiciness based on their preferred degree of doneness