Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Dairy Res ; : 1-14, 2022 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-35983800

RESUMEN

This study evaluated the impact of three distinct diets; perennial ryegrass (GRS), perennial ryegrass/white clover (CLV) and total mixed ration (TMR), on the sensory properties and volatile profile of whole milk powder (WMP). The samples were evaluated using a hedonic sensory acceptance test (n = 99 consumers) and by optimised descriptive profiling (ODP) using trained assessors (n = 33). Volatile profiling was achieved by gas chromatography mass spectrometry using three different extraction techniques; headspace solid phase micro-extraction, thermal desorption and high capacity sorptive extraction. Significant differences were evident in both sensory perception and the volatile profiles of the WMP based on the diet, with WMP from GRS and CLV more similar than WMP from TMR. Consumers scored WMP from CLV diets highest for overall acceptability, flavour and quality, and WMP from TMR diets highest for cooked flavour and aftertaste. ODP analysis found that WMP from TMR diets had greater caramelised flavour, sweet aroma and sweet taste, and that WMP from GRS diets had greater cooked aroma and cooked flavour, with WMP derived from CLV diets having greater scores for liking of colour and creamy aroma. Sixty four VOCs were identified, twenty six were found to vary significantly based on diet and seventeen of these were derived from fatty acids; lactones, alcohols, aldehydes, ketones and esters. The abundance of δ-decalactone and δ-dodecalactone was very high in WMP derived from CLV and GRS diets as was γ-dodecalactone derived from a TMR diet. These lactones appeared to influence sweet, creamy, and caramelised attributes in the resultant WMP samples. The differences in these VOC derived from lipids due to diet are probably further exacerbated by the thermal treatments used in WMP manufacture.

2.
J Dairy Sci ; 101(7): 5738-5750, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29550125

RESUMEN

Centrifugation is a common milk pretreatment method for removal of Clostridium spores which, on germination, can produce high levels of butyric acid and gas, resulting in rancid, gassy cheese. The aim of this study was to determine the effect of centrifugation of milk, as well as incorporation of high heat-treated centrifugate into cheese milk, on the microbial and volatile profile of Maasdam cheese. To facilitate this, 16S rRNA amplicon sequencing in combination with a selective media-based approach were used to study the microbial composition of cheese during maturation, and volatile organic compounds within the cheese matrix were analyzed by HPLC and solid-phase microextraction coupled with gas chromatography-mass spectrometry. Both culture-based and molecular approaches revealed major differences in microbial populations within the cheese matrix before and after warm room ripening. During warm room ripening, an increase in counts of propionic acid bacteria (by ∼101.5 cfu) and nonstarter lactic acid bacteria (by ∼108 cfu) and a decrease in the counts of Lactobacillus helveticus (by ∼102.5 cfu) were observed. Lactococcus species dominated the curd population throughout ripening, followed by Lactobacillus, Propionibacterium, and Leuconostoc, and the relative abundance of these accounted for more than 99% of the total genera, as revealed by high-throughput sequencing. Among subdominant microflora, the overall relative abundance of Clostridium sensu stricto was lower in cheeses made from centrifuged milk than control cheeses, which coincided with lower levels of butyric acid. Centrifugation as well as incorporation of high heat-treated centrifugate into cheese milk seemed to have little effect on the volatile profile of Maasdam cheese, except for butyric acid levels. Overall, this study suggests that centrifugation of milk before cheesemaking is a suitable method for controlling undesirable butyric acid fermentation without significantly altering the levels of other volatile organic compounds of Maasdam cheese.


Asunto(s)
Queso/microbiología , Queso/normas , Manipulación de Alimentos/métodos , Compuestos Orgánicos Volátiles/análisis , Animales , Centrifugación , Calor , Leche , ARN Ribosómico 16S
3.
Sensors (Basel) ; 18(8)2018 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-30082608

RESUMEN

Cocoa and dark chocolate have a wide variety of powerful antioxidants and other nutrients that can positively affect human health. Probiotic dark chocolate has the potential to be a new product in the growing number of functional foods. In this study, encapsulated potential probiotic Lactobacillus plantarum 564 and commercial probiotic Lactobacillus plantarum 299v were added in the production of dark chocolate. The results show very good survival of probiotic bacteria after production and during storage, reaching 108cfu/g in the first 60 days and over 106cfu/g up to 180 days. No statistically significant difference (p > 0.05) in chemical composition and no major differences in the volatile profiles between control and experimental chocolate samples were observed, indicating no impact of probiotic bacteria on compositional and sensory characteristics of dark chocolate. The sensory evaluation of control and both probiotic dark chocolate samples showed excellent sensory quality after 60 and 180 days of storage, demonstrating that probiotics did not affect aroma, texture and appearance of chocolate. Due to a high viability of bacterial cells and acceptable sensory properties, it can be concluded that encapsulated probiotics Lb. plantarum 564 and Lb. plantarum 299v could be successfully used in the production of probiotic dark chocolate.


Asunto(s)
Chocolate/análisis , Chocolate/microbiología , Lactobacillus plantarum/aislamiento & purificación , Viabilidad Microbiana , Probióticos , Gusto , Humanos , Volatilización
4.
J Dairy Sci ; 100(8): 6053-6073, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28624283

RESUMEN

The purpose of this study was to investigate the effects of pasture-based versus indoor total mixed ration (TMR) feeding systems on the chemical composition, quality characteristics, and sensory properties of full-fat Cheddar cheeses. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a TMR diet of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass only pasture (GRS); and group 3 was maintained outdoors on perennial ryegrass/white clover pasture (CLV). Full-fat Cheddar cheeses were manufactured in triplicate at pilot scale from each feeding system in September 2015 and were examined over a 270-d ripening period at 8°C. Pasture-derived feeding systems were shown to produce Cheddar cheeses yellower in color than that of TMR, which was positively correlated with increased cheese ß-carotene content. Feeding system had a significant effect on the fatty acid composition of the cheeses. The nutritional composition of Cheddar cheese was improved through pasture-based feeding systems, with significantly lower thrombogenicity index scores and a greater than 2-fold increase in the concentration of vaccenic acid and the bioactive conjugated linoleic acid C18:2 cis-9,trans-11, whereas TMR-derived cheeses had significantly higher palmitic acid content. Fatty acid profiling of cheeses coupled with multivariate analysis showed clear separation of Cheddar cheeses derived from pasture-based diets (GRS or CLV) from that of a TMR system. Such alterations in the fatty acid profile resulted in pasture-derived cheeses having reduced hardness scores at room temperature. Feeding system and ripening time had a significant effect on the volatile profile of the Cheddar cheeses. Pasture-derived Cheddar cheeses had significantly higher concentrations of the hydrocarbon toluene, whereas TMR-derived cheese had significantly higher concentration of 2,3-butanediol. Ripening period resulted in significant alterations to cheese volatile profiles, with increases in acid-, alcohol-, aldehyde-, ester-, and terpene-based volatile compounds. This study has demonstrated the benefits of pasture-derived feeding systems for production of Cheddar cheeses with enhanced nutritional and rheological quality compared with a TMR feeding system.


Asunto(s)
Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Queso/análisis , Leche/química , Animales , Butileno Glicoles , Bovinos , Dieta/veterinaria , Femenino , Poaceae , Gusto
5.
J Dairy Sci ; 99(7): 5047-5063, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27085405

RESUMEN

Accurate quantification of free fatty acids (FFA) in dairy products is important for quality control, nutritional, antimicrobial, authenticity, legislative, and flavor purposes. In this study, the performance of 2 widely used gas chromatographic flame ionization detection methods for determination of FFA in dairy products differing in lipid content and degree of lipolysis were evaluated. We used a direct on-column approach where the isolated FFA extract was injected directly and a derivatization approach where the FFA were esterified in the injector to methyl esters using tetramethylammonium hydroxide as a catalyst. A comprehensive validation was undertaken to establish method linearity, limits of detection, limits of quantification, accuracy, and precision. Linear calibrations of 3 to 700mg/L (R(2)>0.999) and 20 to 700mg/L (R(2)>0.997), and limits of detection and limits of quantification of 0.7 and 3mg/L and 5 and 20mg/L were obtained for the direct injection on-column and the derivatization method, respectively. Intraday precision of 1.5 to 7.2% was obtained for both methods. The direct injection on-column method had the lower levels of limits of detection and quantification, because FFA are directly injected onto the GC as opposed to the split injection used in the derivatization method. However, the direct injection on-column method experienced accumulative column phase deterioration and irreversible FFA absorption because of the acidic nature of the injection extract, which adversely affected method robustness and the quantification of some longer chain FFA. The derivatization method experienced issues with quantification of butyric acid at low concentrations because of coelution with the injection solvent peak, loss of polyunsaturated FFA due to degradation by tetramethylammonium hydroxide, and the periodic emergence of by-product peaks of the tetramethylammonium hydroxide reaction that interfered with the quantification of some short-chain FFA. The derivatization method is more robust, and because the derivatization step can be automated, it is more suitable for routine analysis of FFA in dairy products. However, considerable scope exists to develop an alternative gas chromatography with flame ionization detection method to quantify FFA in dairy products without any limitations that is robust and accurate.


Asunto(s)
Productos Lácteos/análisis , Ácidos Grasos no Esterificados/análisis , Ionización de Llama/métodos , Ionización de Llama/instrumentación
6.
Wounds ; 36(1): 23-33, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38417821

RESUMEN

INTRODUCTION: A large SNF system in the United States adopted a holistic wound care model that included an AI DWMS to improve PI care. OBJECTIVE: To compare the trend in PI point prevalence rates and average days to healing linked to adopting technology in practice from 2021 to 2022, and to assess the rate of received PI F686 citations in facilities that adopted the technology compared with those that did not. METHODS: The study used the DWMS database to compare anonymized PI data assessed in 2021 (15 583 patients) vs 2022 (30 657 patients) from all SNF facilities that adopted the technology in 2021 and 2022. F686 citations data were provided by the SNF organization. RESULTS: There was a 13.1% reduction in PI prevalence from 2021 to 2022 across all PI stages. Facilities that adopted the technology demonstrated a significant reduction in days to healing from 2021 to 2022, with an average of 17.7 days saved per PI or a 37.4% faster healing rate (P < .001). A significant reduction in the average days to healing was noted for all PI stages, with the most significant savings observed for stages 3 and 4, with an average savings of 35 days (stage 3) and 85 days (stage 4) in 2022 vs 2021 (P < .001). From 2021 to 2022, facilities that adopted the technology reported an overall 8.2% reduction in F-686 citations severity >G compared to those that did not adopt the technology. CONCLUSION: Use of technology as part of a comprehensive wound care program has the potential to not only improve patient care and quality of life, but to realize considerable annual savings in additional PI out-of-pocket expenses (up to $1 410 000) and of clinicians' time (44 808 hours).


Asunto(s)
Úlcera por Presión , Instituciones de Cuidados Especializados de Enfermería , Humanos , Estados Unidos/epidemiología , Prevalencia , Úlcera por Presión/epidemiología , Úlcera por Presión/terapia , Calidad de Vida
7.
Microbiome ; 12(1): 78, 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38678226

RESUMEN

BACKGROUND: Artisanal cheeses usually contain a highly diverse microbial community which can significantly impact their quality and safety. Here, we describe a detailed longitudinal study assessing the impact of ripening in three natural caves on the microbiome and resistome succession across three different producers of Cabrales blue-veined cheese. RESULTS: Both the producer and cave in which cheeses were ripened significantly influenced the cheese microbiome. Lactococcus and the former Lactobacillus genus, among other taxa, showed high abundance in cheeses at initial stages of ripening, either coming from the raw material, starter culture used, and/or the environment of processing plants. Along cheese ripening in caves, these taxa were displaced by other bacteria, such as Tetragenococcus, Corynebacterium, Brevibacterium, Yaniella, and Staphylococcus, predominantly originating from cave environments (mainly food contact surfaces), as demonstrated by source-tracking analysis, strain analysis at read level, and the characterization of 613 metagenome-assembled genomes. The high abundance of Tetragenococcus koreensis and Tetragenococcus halophilus detected in cheese has not been found previously in cheese metagenomes. Furthermore, Tetragenococcus showed a high level of horizontal gene transfer with other members of the cheese microbiome, mainly with Lactococcus and Staphylococcus, involving genes related to carbohydrate metabolism functions. The resistome analysis revealed that raw milk and the associated processing environments are a rich reservoir of antimicrobial resistance determinants, mainly associated with resistance to aminoglycosides, tetracyclines, and ß-lactam antibiotics and harbored by aerobic gram-negative bacteria of high relevance from a safety point of view, such as Escherichia coli, Salmonella enterica, Acinetobacter, and Klebsiella pneumoniae, and that the displacement of most raw milk-associated taxa by cave-associated taxa during ripening gave rise to a significant decrease in the load of ARGs and, therefore, to a safer end product. CONCLUSION: Overall, the cave environments represented an important source of non-starter microorganisms which may play a relevant role in the quality and safety of the end products. Among them, we have identified novel taxa and taxa not previously regarded as being dominant components of the cheese microbiome (Tetragenococcus spp.), providing very valuable information for the authentication of this protected designation of origin artisanal cheese. Video Abstract.


Asunto(s)
Queso , Microbiología de Alimentos , Microbiota , Queso/microbiología , Queso/normas , Microbiota/fisiología , Transferencia de Gen Horizontal/genética , Metagenoma/genética , Farmacorresistencia Microbiana/genética
8.
Wounds ; 35(10): E330-E338, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37956346

RESUMEN

BACKGROUND: Evidence shows that ongoing accurate wound assessments using valid and reliable measurement methods is essential to effective wound monitoring and better wound care management. Relying on subjective interpretation in measuring wound dimensions and assuming a rectilinear shape of all wounds renders an inconsistent and inaccurate wound area measurement. OBJECTIVE: The authors investigated the discrepancy in wound area measurements using a DWMS versus TPR methods and compared debridement codes submitted for reimbursement by assessment method. METHODS: The width and length of 177 wounds in 56 patients were measured at an outpatient clinic in the United States using the TPR method (width × length formula) and a DWMS (traced wound dimensions). The maximal allowable payment for debridement was calculated for both methods using the reported CPT codes based on each 20-cm2 estimated surface area. RESULTS: The average wound surface area was significantly higher with the TPR method than with the DWMS (20.20 and 12.81, respectively; P = .025). For patients with dark skin tones, ill-defined wound edges, irregular wound shapes, unhealthy tissues, and the presence of necrotic tissues, the use of the DWMS resulted in significantly lower mean differences in wound area measurements of 14.4 cm2 (P < .008), 8.2 cm2 (P = .040), 6.8 cm2 (P = .045), 13.1 cm2 (P = .036), and 7.6 cm2 (P = .043), respectively, compared with the TPR method. Use of the DWMS for wound surface area measurement resulted in a 10.6% lower reimbursement amount for debridement, with 82 fewer submitted codes, compared with the TPR method. CONCLUSIONS: Compared with the DWMS, TPR measurements overestimated wound area more than 36.6%. This overestimation was associated with dark skin tones and wounds with irregular edges, irregular shapes, and necrotic tissue.


Asunto(s)
Inteligencia Artificial , Cicatrización de Heridas , Humanos , Desbridamiento/métodos , Necrosis
9.
Paediatr Anaesth ; 22(2): 170-2, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21851474

RESUMEN

A 15 month old boy with a ventricular septal defect (VSD) underwent percutaneous device closure of the VSD. Five days later he collapsed; on arrival to hospital he was asystolic and received prolonged cardio-pulmonary resuscitation (CPR) with intermittent return of spontaneous circulation (ROSC). He had recurrent episodic complete heart block with no ventricular escape rhythm, associated with loss of cardiac output, unresponsive to transcutaneous pacing. He was transferred to theatre, while receiving CPR, for urgent removal of the VSD device. Estimated total 'down time' was 70 min. The device was removed and patch closure of the VSD was performed. He made a full neurological recovery. Device closure of septal defects has become widespread. We discuss the incidence and type of arrythmias associated with their use. This case highlights an uncommon but life threatening complication of a VSD device. It also highlights that good quality CPR may lead to positive outcomes following pediatric cardiac arrest.


Asunto(s)
Paro Cardíaco/etiología , Paro Cardíaco/terapia , Bloqueo Cardíaco/etiología , Bloqueo Cardíaco/terapia , Defectos del Tabique Interventricular/terapia , Dispositivo Oclusor Septal/efectos adversos , Puente Cardiopulmonar , Reanimación Cardiopulmonar , Cianosis/etiología , Remoción de Dispositivos , Ecocardiografía , Electroencefalografía , Defectos del Tabique Interventricular/complicaciones , Defectos del Tabique Interventricular/cirugía , Humanos , Hipertensión Pulmonar/etiología , Lactante , Masculino , Monitoreo Fisiológico , Marcapaso Artificial
10.
PLoS One ; 17(7): e0271742, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35901189

RESUMEN

OBJECTIVES: This time-motion study explored the amount of time clinicians spent on wound assessments in a real-world environment using wound assessment digital application utilizing Artificial Intelligence (AI) vs. manual methods. The study also aimed at comparing the proportion of captured quality wound images on the first attempt by the assessment method. METHODS: Clinicians practicing at Valley Wound Center who agreed to join the study were asked to record the time needed to complete wound assessment activities for patients with active wounds referred for a routine evaluation on the follow-up days at the clinic. Assessment activities included: labelling wounds, capturing images, measuring wounds, calculating surface areas, and transferring data into the patient's record. RESULTS: A total of 91 patients with 115 wounds were assessed. The average time to capture and access wound image with the AI digital tool was significantly faster than a standard digital camera with an average of 62 seconds (P<0.001). The digital application was significantly faster by 77% at accurately measuring and calculating the wound surface area with an average of 45.05 seconds (P<0.001). Overall, the average time to complete a wound assessment using Swift was significantly faster by 79%. Using the AI application, the staff completed all steps in about half of the time (54%) normally spent on manual wound evaluation activities. Moreover, acquiring acceptable wound image was significantly more likely to be achieved the first time using the digital tool than the manual methods (92.2% vs. 75.7%, P<0.004). CONCLUSIONS: Using the digital assessment tool saved significant time for clinicians in assessing wounds. It also successfully captured quality wound images at the first attempt.


Asunto(s)
Inteligencia Artificial , Humanos , Movimiento (Física) , Estudios de Tiempo y Movimiento
11.
Foods ; 10(9)2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34574176

RESUMEN

Volatile profiling of whole milk powder is valuable for obtaining information on product quality, adulteration, legislation, shelf life, and aroma. For routine analysis, automated solventless volatile extraction techniques are favored due their simplicity and versatility, however no single extraction technique can provide a complete volatile profile due to inherent chemical bias. This study was undertaken to compare and contrast the performance of headspace solid phase microextraction, thermal desorption, and HiSorb (a sorptive extraction technique in both headspace and direct immersion modes) for the volatile analysis of whole milk powder by gas chromatography mass spectrometry. Overall, 85 unique volatiles were recovered and identified, with 80 extracted and identified using a non-polar gas chromatography column, compared to 54 extracted, and identified using a polar gas chromatography column. The impact of salting out was minimal in comparison to gas chromatography column polarity and the differences between the extraction techniques. HiSorb extracted the most and greatest abundance of volatiles, but was heavily influenced by the number and volume of lactones extracted in comparison to the other techniques. HiSorb extracted significantly more volatiles by direct immersion than by headspace. The differences in volatile selectivity was evident between the techniques and highlights the importance of using multiple extraction techniques in order to obtain a more complete volatile profile. This study provides valuable information on the volatile composition of whole milk powder and on differences between extraction techniques under different conditions, which can be extrapolated to other food and beverages.

12.
Antioxidants (Basel) ; 10(5)2021 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-34064839

RESUMEN

The in vitro antioxidant effects of the most potent antioxidants of rosemary, namely carnosol, carnosic acid and rosmarinic acid (c: ca: ra) were assessed in fat-filled milk powders (FFMPs) under accelerated conditions (40 °C and relative humidity (RH) 23%) over 90 days. Lipid oxidation was assessed in FFMPs by measuring peroxide values (PVs), thiobarbituric acid reactive substances (TBARS) and aroma volatiles using headspace (HS) solid-phase microextraction (SPME) coupled to gas-chromatography-mass spectrometry (GC-MS). The antioxidant potency of c: ca: ra exhibited a concentration-related effect (308 ppm > 200 ppm > 77 ppm), with the highest concentration being the most effective at controlling the formation of TBARS and PVs. At a concentration of 308 ppm c: ca: ra were particularly effective (p < 0.05) in inhibiting all the evaluated oxidation indices (primary and secondary) compared to the control samples, but in some cases less effectively (p < 0.05) than butylated hydroxyanisole: butylated hydroxytoluene (BHA: BHT) (200 ppm).

13.
Pediatr Crit Care Med ; 10(1): 41-4, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19057434

RESUMEN

OBJECTIVE: To investigate the long-term health-related quality of life (HRQOL) outcomes for patients requiring at least 28 days of pediatric intensive care. DESIGN: Retrospective cohort and prospective follow-up study. SETTING: A 21-bed pediatric intensive care unit (PICU) in a university-affiliated, tertiary referral pediatric hospital. PATIENTS: One hundred ninety-three patients who spent 28 days or longer in the PICU between January 1, 1997 and December 31, 2004. INTERVENTIONS: Quality of life was measured using the Pediatric Quality of Life Inventory (Peds QL 4.0) parent-proxy version at 2 to 10 yrs after discharge. The PedsQL 4.0 is a modular measure of HRQOL, which is reliable in children aged 2 to 18 yrs. It generates a total score and physical, emotional, social, school, and psychosocial subscores. MEASUREMENTS AND MAIN RESULTS: Of the 193 patients, 41 died during their PICU admission and 27 died between PICU discharge and follow-up. Quality of life questionnaires were posted to parents of 108 of the 125 survivors and 70 were returned completed. Forty children (57.1%) had scores indicating a normal quality of life, whereas 30 (42.9%) had scores indicating impaired HRQOL. Of these, 14 (20%) had scores indicating poor quality of life with ongoing disabling health problems requiring hospitalization or the equivalent. CONCLUSIONS: Our results indicate that, while long PICU stay is associated with significant mortality, the long-term HRQOL is normal for the majority of surviving children.


Asunto(s)
Cuidados Críticos/métodos , Unidades de Cuidado Intensivo Pediátrico , Calidad de Vida , Adolescente , Factores de Edad , Niño , Preescolar , Estudios de Cohortes , Continuidad de la Atención al Paciente/estadística & datos numéricos , Enfermedad Crítica/terapia , Femenino , Estudios de Seguimiento , Hospitales Universitarios , Humanos , Irlanda , Tiempo de Internación , Cuidados a Largo Plazo , Masculino , Alta del Paciente , Probabilidad , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Estadísticas no Paramétricas , Factores de Tiempo
14.
J Agric Food Chem ; 67(1): 499-506, 2019 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-30525571

RESUMEN

Accurate quantification of free fatty acids in dairy products is important for both product quality control and legislative purposes. In this study, a novel fatty acid butyl ester method was developed, where extracted free fatty acids are converted to butyl esters prior to gas chromatography with flame ionization detection. The method was comprehensively validated to establish linearity (20-700 mg/L; R2 > 0.9964), limits of detection (5-8 mg/L), limits of quantification (15-20 mg/L), accuracy (1.6-5.4% relative error), interday precision (4.4-5.3% relative standard deviation), and intraday precision (0.9-5.6% relative standard deviation) for each individual free fatty acid. A total of 17 dairy samples were analyzed, covering diverse sample matrices, fat content, and degrees of lipolysis. The method was compared to direct on-column injection and fatty acid methyl ester methods and overcomes limitations associated with these methods, such as either column-phase absorption or deterioration, accurate quantification of short-chain free fatty acids, and underestimation of polyunsaturated free fatty acid.


Asunto(s)
Cromatografía de Gases/métodos , Productos Lácteos/análisis , Ésteres/análisis , Ácidos Grasos no Esterificados/análisis , Ionización de Llama/métodos
15.
Food Chem ; 292: 75-80, 2019 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-31054695

RESUMEN

Lipid oxidation is a major contributor to the deterioration of the sensory quality of fat-containing dairy powders. Hydroperoxides are the primary oxidation products from unsaturated fatty-acids that readily yield a complex mixture of volatile organic compounds that can adversely impact product quality and shelf life. Headspace solid-phase microextraction gas-chromatography mass-spectrometry was chosen to quantify thirteen lipid oxidation compounds in whole milk powder encompassing a range of volatilities and chemical classes. A central composite rotatable design (CCD, α = 1.1) based on a 23 factorial table was used with response surface methodology to optimize the HS-SPME parameters; determined at; 45 min extraction time and 43 °C extraction temperature. The significant model terms were found to be extraction temperature (p < 0.05) and the interaction between time and temperature (p < 0.05). Precision, accuracy, LOD and LOQ were determined and the method was validated for whole milk powder.


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas/métodos , Lípidos/química , Leche/química , Microextracción en Fase Sólida/métodos , Compuestos Orgánicos Volátiles/análisis , Animales , Análisis de los Alimentos/métodos , Límite de Detección , Lípidos/análisis , Oxidación-Reducción , Polvos/análisis , Polvos/química , Reproducibilidad de los Resultados , Volatilización
16.
Foods ; 8(4)2019 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-31013643

RESUMEN

The purpose of this study was to examine the impact of a variety of supplemental feeds on the composition and quality of milk in a pasture-based dairy system. Four pasture-supplemented feeding systems were compared: Group 1 supplementation with 16% crude protein parlour concentrate (CONC); Group 2 supplementation with palm kernel expeller plus parlour concentrate (PKE); Group 3 supplemented with soya hulls plus parlour concentrate (SOYA); Group 4 was supplemented with molassed beet pulp plus parlour concentrate (BEET). Supplemental feeding system was demonstrated to have a significant effect on the size of native casein micelles and the gelation properties of milks. While CONC feeding produced significantly higher casein micelle size, gel strength (Young's Modulus) was significantly negatively correlated with casein micelle size. Supplemental feeding system had a significant effect on a number of fatty acids (FA) and indices derived therefrom, including total saturated and unsaturated fatty acids, de novo produced FA, omega 3, and omega 6 FA. The volatile profile of milks was also affected by supplemental feed choice, whereby multivariate analysis demonstrated that the CONC diet was distinctly different to that of the PALM, SOYA, and BEET milks. Multivariate analysis demonstrated that it is possible to distinguish milks from different pasture-supplemented feeding systems by their FA profile.

17.
Food Res Int ; 123: 722-731, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31285022

RESUMEN

The untargeted metabolic profiles of ripened Maasdam cheese samples prepared from milk derived from three herd groups, fed: (1) indoors on total mixed ration (TMR), or outdoors on (2) grass only pasture (GRA) or (3) grass and white clover pasture (CLO) were studied using high resolution nuclear magnetic resonance (1H NMR), high resolution magic angle spinning nuclear magnetic resonance (1H HRMAS NMR) and headspace (HS) gas chromatography mass spectrometry (GC-MS). A total of 31 compounds were identified using 1H NMR and 32 volatile compounds including 7 acids, 5 esters, 4 alcohols, 4 ketones, 4 sulfur compounds, 2 aldehydes, 3 hydrocarbons, 2 terpenes and a lactone were identified using GC-MS in Maasdam cheeses ripened for 97-d. On comparing the 1H NMR metabolic profiles, TMR-derived cheese had higher levels of citrate compared to GRA-derived cheese. The toluene content of cheese was significantly higher in GRA or CLO compared to TMR cheeses and dimethyl sulfide was identified only in CLO-derived cheese samples as detected using HS GC-MS. These compounds are proposed as indicator compounds for Maasdam cheese derived from pasture-fed milk. Clear differences between outdoor or indoor feeding systems in terms of cheese metabolites were detected in the lipid phase, as indicated by principal component analysis (PCA) from 1H HRMAS NMR spectra, although differences based on PCA of all 1H NMR spectra and HS-GC-MS were less clear. Overall, this study presented the metabolite profile and identified specific compounds which may be useful for discriminating between ripened Maasdam cheese and related cheese varieties manufactured from indoor or outdoor herd-feeding systems.


Asunto(s)
Queso/análisis , Dieta/veterinaria , Metaboloma , Alcoholes/análisis , Aldehídos/análisis , Alimentación Animal , Animales , Bases de Datos Factuales , Ésteres/análisis , Manipulación de Alimentos/métodos , Cromatografía de Gases y Espectrometría de Masas , Cetonas/análisis , Espectroscopía de Resonancia Magnética , Leche/química , Análisis Multivariante , Terpenos/análisis , Tolueno/análisis , Compuestos Orgánicos Volátiles/análisis
18.
Nat Commun ; 9(1): 476, 2018 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-29396402

RESUMEN

Though used widely in cancer therapy, paclitaxel only elicits a response in a fraction of patients. A strong determinant of paclitaxel tumor response is the state of microtubule dynamic instability. However, whether the manipulation of this physiological process can be controlled to enhance paclitaxel response has not been tested. Here, we show a previously unrecognized role of the microtubule-associated protein CRMP2 in inducing microtubule bundling through its carboxy terminus. This activity is significantly decreased when the FER tyrosine kinase phosphorylates CRMP2 at Y479 and Y499. The crystal structures of wild-type CRMP2 and CRMP2-Y479E reveal how mimicking phosphorylation prevents tetramerization of CRMP2. Depletion of FER or reducing its catalytic activity using sub-therapeutic doses of inhibitors increases paclitaxel-induced microtubule stability and cytotoxicity in ovarian cancer cells and in vivo. This work provides a rationale for inhibiting FER-mediated CRMP2 phosphorylation to enhance paclitaxel on-target activity for cancer therapy.


Asunto(s)
Péptidos y Proteínas de Señalización Intercelular/metabolismo , Microtúbulos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neoplasias Ováricas/tratamiento farmacológico , Paclitaxel/farmacología , Proteínas Tirosina Quinasas/genética , Tratamiento con ARN de Interferencia , Moduladores de Tubulina/farmacología , Animales , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ratones Desnudos , Microscopía Confocal , Microscopía Fluorescente , Microtúbulos/efectos de los fármacos , Microtúbulos/ultraestructura , Simulación de Dinámica Molecular , Terapia Molecular Dirigida , Trasplante de Neoplasias , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/ultraestructura , Fosforilación/efectos de los fármacos , Fosforilación/genética , Multimerización de Proteína/efectos de los fármacos , Multimerización de Proteína/genética , Proteínas Tirosina Quinasas/metabolismo , ARN Interferente Pequeño
19.
Oncotarget ; 8(11): 17960-17980, 2017 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-28152500

RESUMEN

Taxanes represent some of the most commonly used chemotherapeutic agents for ovarian cancer treatment. However, they are only effective in approximately 40% of patients. Novel therapeutic strategies are required to potentiate their effect and improve patient outcome. A hallmark of many cancers is the constitutive activation of the PI3K/AKT pathway, which drives cell survival and metabolism. We discovered a striking decrease in AKT activity coupled with a significant reduction in glucose 6-phosphate and ATP levels during mitotic arrest in the majority of ovarian cancer cell lines tested, indicating a potential metabolic vulnerability. A high-content siRNA screen to detect novel metabolic targets in mitotically arrested ovarian cancer cells identified the glycolytic enzyme PFKFB4. PFKFB4 depletion increased caspase 3/7 activity, and levels of reactive oxygen species only in mitotically arrested cells, and significantly enhanced mitotic cell death after paclitaxel treatment. Depletion of PFKFB3 demonstrated a similar phenotype. The observation that some ovarian cancer cells lose AKT activity during mitotic arrest and become vulnerable to metabolic targeting is a new concept in cancer therapy. Thus, combining mitotic-targeted therapies with glycolytic inhibitors may act to potentiate the effects of antimitotics in ovarian cancer through mitosis-specific cell death.


Asunto(s)
Puntos de Control del Ciclo Celular/fisiología , Muerte Celular/fisiología , Neoplasias Ováricas/patología , Fosfofructoquinasa-2/metabolismo , Antineoplásicos/farmacología , Western Blotting , Línea Celular Tumoral , Femenino , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Técnicas de Silenciamiento del Gen , Humanos , Mutagénesis Sitio-Dirigida , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Paclitaxel/farmacología , Reacción en Cadena de la Polimerasa , Proteínas Proto-Oncogénicas c-akt/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA