Quantification of Trace Volatile Sulfur Compounds in Milk by Solid-Phase Microextraction and Gas Chromatography–Pulsed Flame Photometric Detection

Volatile sulfur compounds have been reported to be responsible for the sulfurous off-flavors generated during the thermal processing of milk; however, their analysis has been a challenge due to their high reactivity, high volatility, and low sensory threshold. In this study, reactive thiols were stabilized and the volatile sulfur compounds in milk were extracted by headspace solidphase microextraction, and analyzed by gas chromatography and pulsed-flame photometric detection. Calibration curves for 7 sulfur-containing compounds were constructed in milk by the standard addition technique. Raw, pasteurized, and UHT milk samples with various fat contents were analyzed. Compared with raw and pasteurized samples, UHT milk contained substantially higher concentrations of hydrogen sulfide, methanethiol, carbon disulfide, dimethyl trisulfide, and dimethyl sulfoxide. The high odor activity values calculated for methanethiol and dimethyl trisulfide suggested that these 2 compounds, in addition to dimethyl sulfide reported in a previous study, could be the most important contributors to the sulfurous note in UHT milkKeywords: volatile sulfur, milk off-flavor, solid-phase microextraction, pulsed-flame photometric detectionOriginally published in Journal of Dairy Science (http://www.journalofdairyscience.org/) and copyrighted by the American Dairy Science Association

Quantitative determination of thermally derived off-flavor compounds in milk using solid-phase microextraction and gas chromatography

Many volatile compounds generated during the thermal processing of milk have been associated with cooked, stale, and sulfurous notes in milk and are considered as off-flavor by most consumers. A headspace solid-phase microextraction (HS-SPME)/gas chromatographic technique for the quantitative analysis of thermally derived off-flavor compounds was developed in this study. The extraction temperature, time, and sample amount were optimized using a randomized 23 central composite rotatable design with 2 central replicates and 2 replicates in each factorial point along with response surface methodology. Calibration curves were constructed in milk using the standard addition technique, and then used to quantify 20 off-flavor compounds in raw, pasteurized, and UHT milk samples with various fat contents. The concentrations of these volatiles in raw and pasteurized milk samples were not significantly different. However, dimethyl sulfide, 2-hexanone, 2-heptanone, 2-nonanone, 2-undecanone, 2-methylpropanal, 3-methylbutanal, heptanal, and decanal were found at higher concentrations in UHT milk as compared with raw and pasteurized milk samples. In addition, the concentration of methyl ketones was greater in UHT milk with higher fat content. The calculated odor activity values suggested that 2,3-butanedione, 2-heptanone, 2-nonanone, 2-methylpropanal, 3-methylbutanal, nonanal, decanal, and dimethyl sulfide could be important contributors to the off-flavor of UHT milk. The HS-SPME technique developed in this study is accurate and relatively simple, and can be used for the quantification of thermally derived off-flavor compounds in milk.First published in Journal of Dairy Science (http://www.journalofdairyscience.org/). Copyrighted by the American Dairy Science Association.Keywords: milk, off-flavor, solid-phase microextraction, quantificatio

Hilando generaciones y moda

El proyecto Hilando Generaciones y Moda tiene como objetivo principal fomentar el intercambio y la convivencia intergeneracional entre jóvenes del ITESO y adultos mayores que acuden al Centro Tapatío de Atención al Adulto Mayor, ubicado en Guadalajara, Jalisco. La problemática que se busca resolver con este proyecto es la falta de interacción y comunicación entre estas dos generaciones, lo que puede llevar a la desconexión y aislamiento social de los adultos mayores, así como a una falta de perspectiva y comprensión por parte de los jóvenes sobre las experiencias y desafíos que enfrentan las personas mayores. El proyecto busca romper con estas barreras mediante la realización de actividades que promuevan la convivencia y el aprendizaje mutuo entre ambas generaciones, permitiendo la integración social y emocional de los adultos mayores, así como el desarrollo de habilidades sociales y empáticas en los jóvenes. A través de la interacción y el diálogo entre ambas generaciones, se espera generar un ambiente de respeto y valoración hacia la sabiduría y experiencia de los adultos mayores, así como una comprensión más profunda de las realidades sociales y culturales que enfrentan. A lo largo del semestre hicimos distintas actividades relacionadas con moda, que fueron propuestas por nosotros mismos. Estos talleres pensados en los adultos mayores nos dejarían productos que reflejaran la identidad de cada adulto y con los que después haremos una exposición final. Nuestras primeras actividades con los adultos fueron hacer un collage y un esqueleto exquisito, en el que hablarían sobre ellos y podríamos conocerlos mejor. Después tuvimos un taller de joyería en el CETAM, donde los adultos crearon dijes personalizados. La siguiente actividad fue un taller de creación y personalización de playeras. Para esta, los adultos nos visitaron en el ITESO, donde compartimos desayuno, baile y creatividad con las pinturas para personalizar cada playera. Este semestre colaboramos con Andrés Moreno, stylist y creador de Vintage Ceremony. Andrés nos asesoró en nuestro camino para nuestra siguiente actividad: una sesión de fotos que buscó resaltar la identidad de cada adulto mayor. En esta sesión de fotos contamos con patrocinio de peinado y maquillaje. Nuestra última actividad será la exposición final, donde mostraremos los resultados de todas las actividades, como prendas hechas por los alumnos de moda (con telas diseñadas por ellos, inspiradas en los adultos).ITESO, A.C

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

The use of Mexican xaxtle as leavening agent in Italian straight dough bread making to produce pulque bread

The "pulque bread" is traditionally produced in Mexico using as starter culture the xaxtle. mixed together with wheat flour, milk, eggs, margarine and cane sugar. The high nutritional value of this typical bread, which is characterized by a low glycemic index as well as high concentration of several prebiotic compounds, together with phytase enzymes, seems to be due to the use of xaxtle as leavening agent. The aim of this research was to determine the microbial composition of dough and the physical chemical characteristics of the bread obtained using xaxtle as starter cultures in straight dough bread making, following the traditional protocol generally adopted by Italian artisan bread-makers. According to the discussed experimental evidences, it is possible to conclude that freeze-dried xaxtle could be employed as starter culture in bread making and the microbial association developed during the dough ripening is characterized by the presence of both yeast and lactic bacteria strains

The use of Mexican xaxtle as leavening agent in Italian straight dough bread making to produce pulque bread

The “pulque bread” is traditionally produced in Mexico using as starter culture the xaxtle, mixed together with wheat flour, milk, eggs, margarine and cane sugar. The high nutritional value of this typical bread, which is characterized by a low glycemic index as well as high concentration of several prebiotic compounds, together with phytase enzymes, seems to be due to the use of xaxtle as leavening agent. The aim of this research was to determine the microbial composition of dough and the physicalchemical characteristics of the bread obtained using xaxtle as starter cultures in straight dough bread making, following the traditional protocol generally adopted by Italian artisan bread-makers. According to the discussed experimental evidences, it is possible to conclude that freeze-dried xaxtle could be employed as starter culture in bread making and the microbial association developed during the dough ripening is characterized by the presence of both yeast and lactic bacteria strains

Reaction Kinetics Analysis of Chemical Changes in Pressure-Assisted Thermal Processing

Pressure-assisted thermal processing (PATP) at T 100°C can be used when bacterial spores inactivation is necessary. In PATP, the adiabatic compression/decompression heat increases/decreases temperature almost instantaneously, and the simultaneous application of high pressure (~600–700 MPa) and temperature (~100–120°C) accelerates spore inactivation. PATP effects on chemical changes are analyzed using a reaction kinetics approach including activation volume (V a) and activation energy (E a) values. Reaction rates increase or decrease with pressure for negative or positive V a values, respectively, while rate temperature and pressure sensitivity depends on the magnitude of E a and V a values, respectively. The complex effects of food matrix, pH, dissolved oxygen, and presence of antioxidants show that optimization of vitamin, pigment and flavor retention while ensuring PATP microbial and enzyme inactivation will require substantially more chemical reaction kinetics research