scholarly journals Metabolomic Predictors for Flavor Potential of Beef Steaks Differing in Quality Grade, Aging Time, and Degree of Donenesss

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Z. M. Hicks ◽  
C. R. Kerth ◽  
K. R. Wall ◽  
D. H. Tucker ◽  
R. K. Miller
Keyword(s):  
Aging Time ◽  
High Performance ◽  
Hplc Analysis ◽  
Solid Phase ◽  
Lipid Fraction ◽  
Acetonitrile Solution ◽  
Processing Plant ◽  
Quality Grade ◽  
Beef Steaks ◽  
Strip Loin

ObjectivesThe objective of this project was to explore metabolomic predictors that could determine the potential of beef strip loin steaks differing in quality grade, aging time, and degree of doneness to develop positive flavors.Materials and MethodsUSDA Select (n = 18) and USDA Upper 2/3 Choice (n = 18) beef strip loins (IMPS 180) were collected from a processing plant. Loins were halved, and each half was wet aged for either 10 or 20 d in a cooler kept at 2°C. After aging, loins were cut into 2.54 cm steaks, individually vacuum packaged and stored in a freezer at –40°C. Prior to cooking steaks were thawed in a 4°C cooler for 12 to 24 h. Steaks were cooked on a flat top griddle set to 204.4°C (± 11.1°C) to one of three degrees of doneness: 63°C (medium rare), 71°C (medium) or 80°C (medium well). A six-member expert trained descriptive attribute panel was trained on 16 major attributes, 4 other attributes, and 3 texture attributes from the beef lexicon for 6 d prior to testing. Panelists were trained to scale each attribute on a sixteen-point intensity scale (0 = none, 15 = extremely intense). Panelists were served two random, representative cubes (1.3 cm × 1.3 cm × steak thickness) from each steak in a plastic souffle cup labeled with a random three-digit code. Panelists were seated in a breadbox-style booth under red lighting to eliminate degree of doneness bias. Portions from one raw steak from Quality Grade (QG) × aging combination from each loin was used for high performance liquid chromatography (HPLC) analysis. Samples were homogenized and extracted with a water/acetonitrile solution before being filtered. The lipid fraction was removed via solid phase extraction. Samples were then centrifuged and injected into the HPLC. Data was analyzed as a factorial arrangement of a completely randomized design.ResultsUSDA Choice steaks had more intense beef flavor identity, brown, roasted, fat-like, salty, sweet, sour, umami, buttery, and overall sweet flavors and were juicier and more tender compared to USDA Select steaks, which were more intense in metallic and bitter flavors (P < 0.05). Steaks aged for 20 d were juicer and more tender than 10-d aged steaks (P < 0.05). However, 20-d aged steaks also had more intense sour, liver-like, and musty earthy/humus flavors and a less intense brown flavor compared to 10 d aged steaks (P < 0.05). Steaks cooked to 80°C had more intense beef identity, brown, roasted, and umami flavors than steaks cooked to a lower degree of doneness (P < 0.05). Steaks cooked to either 63°C or 71°C had more intense bloody, metallic, and sour flavors and are juicier and more tender than steaks cooked to the higher degree of doneness (P < 0.05). The HPLC analysis of raw steak samples indicated a total of 54 compounds appeared in at least 80% of one treatment. Additionally, there were 2 peptides and 1 sugar that were significantly (P < 0.05) upregulated in the Choice, 20-d-aged strip loins. Additionally, 14 compounds were identified that were shared across all four QG × aging combinations. This included 11 peptides, 2 phospholipids, and 1 heterocyclic aromatic hydrocarbon.ConclusionThese compounds could be indications of the potential for steaks to form positive flavor attributes found in USDA Choice steaks and 20-d aged steaks as described by trained panel analysis.

scholarly journals Metabolomic Predictors for Flavor Potential of Beef Steaks Differing in Quality Grade, Aging Time, and Degree of Donenesss

2019 ◽  
Vol 3 (2) ◽  
pp. 120-120
Author(s):  
Z. M. Hicks ◽  
C. R. Kerth ◽  
K. R. Wall ◽  
D. H. Tucker ◽  
R. K. Miller
Keyword(s):  
Aging Time ◽  
Quality Grade ◽  
Beef Steaks

scholarly journals Occurrence of tetracycline, chlortetracycline, and oxytetracycline residues in raw cow’s milk

2009 ◽  
Vol 27 (No. 5) ◽  
pp. 379-385 ◽  
Author(s):  
P. Navrátilová ◽  
I. Borkovcová ◽  
M. Dračková ◽  
B. Janštová ◽  
L. Vorlová
Keyword(s):  
High Performance ◽  
Hplc Analysis ◽  
Solid Phase ◽  
Rapid Test ◽  
Cow’S Milk ◽  
Tetracycline Antibiotics ◽  
Cow's Milk ◽  
Antibiotics Residues ◽  
Liquid Chromatographic ◽  
Raw Cow’S Milk

The objective of this study was the detection of tetracycline, chlortetracycline and oxytetracycline residues in raw cow’s milk. When analysing bulk milk (<i>n</i> = 57) and tanker trailer’a (<i>n</i> = 113) samples, two methods were used simultaneously: a specific rapid test Milk Tetrasensor Kit and high performance liquid chromatography (HPLC) with ultraviolet detection and isocratic elution. For HPLC analysis, Breeze (Waters, USA), a liquid chromatographic system, was used. The samples underwent solid phase extraction before the HPLC analysis. The Nova Pack C8 column (3.9 × 150 mm, 4 μm, Waters) and mobile phase (0.8 ml/min) consisting of acetonitrile, methanol, and 0.05 mol/l of oxalic acid in a 13:13:74 ratio were used. None of the samples analysed with the use of the specific rapid test displayed the presence of tetracycline antibiotics. In all of the samples analysed by means of HPLC, low concentrations of tetracycline antibiotics residues were detected. None of the samples displayed the presence of chlortetracycline. All of the analysed samples displayed residues of tetracycline. Oxytetracycline residues were detected only in 50.6% of analysed samples.

scholarly journals Evaluation of Consumer Preferences and Volatile Compounds of Beef Strip Loin Steaks Differing by Quality Grade, Postmortem Aging, and Degree of Doneness

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
D. H. Tucker ◽  
C. R. Kerth ◽  
K. R. Wall ◽  
Z. M. Hicks ◽  
R. K. Miller
Keyword(s):  
Volatile Compounds ◽  
Solid Phase ◽  
Consumer Preferences ◽  
Random Effect ◽  
Consumer Preference ◽  
Aroma Compounds ◽  
Processing Plant ◽  
Quality Grade ◽  
Volatile Aroma ◽  
Volatile Aroma Compounds

ObjectivesThe purpose of this study was to determine consumer preferences and volatile aroma compounds for differences in flavor concerning quality grade, day of age, and degree of doneness on beef strip loins.Materials and MethodsUSDA Select (n = 18) and USDA upper 2/3 Choice (n = 18), boneless beef strip loins (IMPS 180), were selected from a commercial processing plant. Loins were cut in half and wet aged for either 10 or 20 d at 2°C. After aging, loins were cut into 2.54 cm steaks, individually vacuum-packaged and stored in a freezer at –40°C. Steaks were thawed at 4°C for 12 to 24 h prior to cooking. Steaks were cooked on a flat top griddle set to 204.4°C (± 11.1°C). The steaks were cooked to one of three degrees of doneness: 63°C (63; medium rare), 71°C (71; medium) or 80°C (80; medium well) and flipped once at the halfway cook temperature. Steaks were held at 60°C no longer than 20 min. Consumer testing was conducted over five sessions with 93 consumers. Each consumer evaluated the samples on five different attributes: overall liking, overall flavor, appearance juiciness, and tenderness. The consumers rated each sample based on a 9-point hedonic scale. Consumer data were run using a full factorial design using grade, age, and degree of doneness as main effects. The order in which samples were served was included as a random effect and data were blocked by session. Portions of cooked samples were collected for GC analysis by being placed into a 20mL glass jar and collected with a solid-phase micro-extraction fiber for 60 min. The SPME was then placed into a GC/MS to separate and identify each volatile chemical compound. Three-way interactions among volatile compounds were determined to be not significant (P > 0.05); therefore, they were removed from the model. Additionally, volatiles that were not present in cells of two-way interactions were not included. Multivariate relationships between consumer preference and GC/MS data were explored using PCA.ResultsUSDA Choice had a higher (P < 0.001) liking score than USDA Select grade beef loins for each of the five attributes tested. The 20-d aged steaks had higher (P < 0.03) scores for overall liking, overall flavor, juiciness, and tenderness. The degree of doneness affected overall liking and juiciness liking (P < 0.001) with 63°C having the greatest score followed by 71°C and then 80°C. For overall flavor, 63°C and 71°C were greater (P = 0.013) than for 80°C. For appearance, the degree of doneness of 63°C was preferred to steaks cooked at 71°C and 80°C (P = 0.002). Of the total volatiles (n = 52) present in the samples, 20 d age had greater (P < 0.04) iso butyraldehyde (pungent), 2-methyl-butanal (chocolate), and 3-methyl-butanal (fatty almond). Whereas, 3-hydroxy-2-butanone (buttery) was greater (P < 0.002) in 10 d age. Octanal (fatty) and nonanal (fatty) were greater (P < 0.04) in USDA Select than USDA Choice. 2-methyl pyrazine (chocolate, meaty, roasted) was greater (P < 0.04) in 20 d aged steaks cooked to 71°C and 80°C compared to other treatment combinations.ConclusionConsumer preferences were distinctly different based on quality grade, age, and degree of doneness. USDA Choice was generally the most preferred along with 63°C and 20 d age steaks. Positive (by their descriptors) volatile aroma compounds can be improved with aging and a degree of doneness of at least 71°C.

Solid-Phase Extraction of Salidroside by Electrospun Nanofibers

2013 ◽  
Vol 798-799 ◽  
pp. 161-164
Author(s):  
Dao Wu Wang ◽  
Xin Xia Feng ◽  
Xiao Long Li ◽  
Long Zhang
Keyword(s):  
High Performance Liquid Chromatography ◽  
Solid Phase Extraction ◽  
High Performance ◽  
Hplc Analysis ◽  
Solid Phase ◽  
Electrospun Nanofibers ◽  
Relative Content ◽  
Extraction Column ◽  
Phase Extraction ◽  
Extraction Recovery

Abstract. The article established electrospun nanofibers as extraction medium to enrich and purify salidroside and detected the content changes by high performance liquid chromatography. 4 g polystyrene was dissolved in 20 mL butanone for spinning. The electrospun nanofibers was processed and loaded into solid extraction column. 3 mL sample was injected and eluted by 10 mL methanol at the speed of 2 mL/min, collecting the elution for the HPLC analysis. The results show that the relative content of solidroside increased from 24% to 55% and the extraction recovery was above 92%. The method is simple and convenient. It can replace traditional solid phase extraction to enrich solidroside.

Liquid-chromatographic measurement of cyclosporin A and its metabolites in blood, bile, and urine.

1988 ◽  
Vol 34 (1) ◽  
pp. 34-39 ◽  
Author(s):  
U Christians ◽  
K O Zimmer ◽  
K Wonigeit ◽  
G Maurer ◽  
K F Sewing
Keyword(s):  
Cyclosporin A ◽  
High Performance ◽  
Hplc Analysis ◽  
Solid Phase ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Preparative Hplc ◽  
Chromatographic Peaks ◽  
Liquid Chromatographic

Abstract Using solid-phase extraction columns and "high-performance" liquid-chromatographic (HPLC) analysis, we could determine cyclosporin A and nine of its metabolites in blood, bile, and urine. To facilitate calculations of concentrations of cyclosporin A and its metabolites from the chromatograms, we used cyclosporin D as internal standard. For the HPLC analysis we used two sequential 250-mm analytical columns filled with reversed-phase octyl (C8) sorbent, eluting with a concave gradient of water, adjusted to pH 3.0 with phosphoric acid, and acetonitrile. Peaks were detected at 205 nm. For characterization of the chromatographic peaks, we isolated, by semi-preparative HPLC, 32 fractions representing peaks potentially related to cyclosporin A metabolites and re-injected them into the HPLC system under the same conditions as authentic cyclosporin A metabolites. Analytical recovery was 70-80%. The inter-assay CV for bile was 7.2%, for urine 12.3%. The method was used for routine monitoring of cyclosporin A and its metabolites.

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