Computational fluid dynamics in drying and cooling operations applied to the food industry

El estudio de la transferencia de masa se debe iniciar desde el punto de vista de los fenómenos de transporte seguido por los procesos de separación macroscópica. Para desarrollar esta área, se requieren progresos en análisis matemático y en herramientas computacionales para el diseño y optimización de los procesos. La dinámica de fluidos computacional (CFD) es una alternativa versátil y, precisa que ha evolucionado hasta lograr un interés creciente en los últimos años en la comunidad científica de la ingeniería de alimentos. En este artículo se presenta una descripción de los fundamentos de la transferencia de masa y las aplicaciones de CFD en las operaciones de transferencia de masa de la industria de alimentos con base en la literatura disponible en la literatura en las bases de datos Science Direct, EBSCO y Scielo entre los años 1999 y 2009. Se encuentra un crecimiento considerable en el desarrollo y las aplicaciones de CFD en las áreas de secado y refrigeración

Effect of hydrodrying conditions on shrinkage of pumpkin (Cucurbita maxima) pieces

(Spa) El método para secar apropiadamente frutas y vegetales debe garantizar la calidad del producto terminado además de ser económicamente viable. Por tal motivo, se han aplicado y desarrollado tecnologías que incluyen pre-trat - amientos y mejoras a la técnica de secado misma. Mediante la metodología llamada “hidrosecado conductivo” basada en la técnica de Ventana de Refractancia (RW TM ), se deshidrataron trozos rectangulares de zapallo (1.2 x 1.1 x 5.9 cm 3 ). Se empleó un baño termostático con agua a 90±2°C, durante 3 h. Se realizó un diseño factorial 2 2 para analizar el efecto de la convección y la conducción sobre el encogimiento de las muestras. Los factores evaluados fueron el tipo de convección con dos niveles: convección natural (NC) y convección forzada (FC); y el tipo de lámina empleada para el secado con dos niveles: Mylar TM (MY) y Mylar con papel aluminio (MY/AL). Se evaluó el factor de cambio de volumen (V/V 0 ) a partir de las dimensiones primarias (ancho, alto, y largo) de las muestras durante el secado. El menor y el mayor encogimiento de acuerdo al factor de cambio de volumen se observó en los tratamientos de convección natural NC-MY/AL y NC-MY, respectivamente. Se encontró una relación exponencial entre el cambio de volumen y la tasa de secado. El ANOVA indicó que el tipo de convección y la interacción convección-lámina fueron estadísticamente significantes en los diferentes análisis.(Eng) The method for properly drying fruits and vegetables should guarantee the quality of the finished product in addition to being economically viable. For this reason, several technologies, including pre-treatments and improvements to the drying technique itself, have been applied and developed. Using the methodology called “conductive hydro-drying” based on the Refractance Window (RW TM ) technique, rectangular pieces of pump - kin (1.2 x 1.1 x 5.9 cm 3 ) were dehydrated using a thermostatic bath with water at 90±2 °C, for 3 hours. Hence, a 2 2 factorial design were performed to analyse the effect of convection and conduction on the shrinkage of samples. The tested factors were the type of convection with two levels: natural convection (NC) and forced convection (FC); and the type of drying foil with two levels: Mylar TM (MY) and Mylar TM with aluminium foil (MY/AL). The volume change factor (V/V 0 ) from primary dimensions (width, height and length) of the samples was evaluated during drying. The smaller and the larger shrinkage, according to the volume change factor, were observed in natural convection treatments NC-MY/AL and NC-MY, respectively. An exponential relationship between drying rate and volume change factor was found. The ANOVA indicated that convection and convection-film interaction were statistically significant

Quality of life in caregivers of patients with schizophrenia: A literature review

<p>Abstract</p> <p>Background</p> <p>A couple of decades ago, hospitals or psychiatric institutions were in charge of caring for patients with schizophrenia; however, nowadays this role is performed by one or more patient's relatives. Evidence shows that informal caregivers experience negative changes in their quality of life (QOL). The aim of this study is to review the main factors associated with the QOL of caregivers of people with schizophrenia.</p> <p>Methods</p> <p>A search through databases from journals published last decade between 1998 and 2008 was performed. In accordance with the inclusion criteria, titles and abstracts of citations obtained from the search were examined independently by two authors and irrelevant articles discarded. The full text of those studies considered relevant by either reviewer were obtained and assessed independently. Where differences of opinion rose they were resolved by discussion. Out of the 258 references, 37 were included in the review.</p> <p>Studies which assessed factors associated with caregivers of people with schizophrenia's quality of life were included and the information summarized.</p> <p>Results</p> <p>Evidence suggest that physical, emotional and economic distress affect negatively caregiver's QOL as a result of a number of unfulfilled needs such as, restoration of patient functioning in family and social roles, economic burden, lack of spare time, among other factors.</p> <p>Conclusion</p> <p>Decreased QOL may be associated with caregivers' burden, lack of social support, course of the disease and family relationships problems. In addition, in developing countries, QOL is affected by caregivers' economic burden. High quality research is needed in order to identify factors associated with QOL over time and testing the efficacy of interventions aiming to improve QOL in caregivers of patients with schizophrenia.</p

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Microwave-Assisted Extraction of Phenolic Compounds from Pineapple Peel Using Deep Eutectic Solvents

Approximately half of the world&rsquo;s pineapple production is marketed as a processed product, leading to the generation of a significant quantity of industrial waste, mainly composed of pineapple peels, cores, and crowns. This study evaluated deep eutectic solvents (DESs) for the assisted microwave extraction of phenolic compounds from pineapple peels and their antioxidant capacity. DESs are considered environmentally friendly solvents characterized by their low toxicity and high capacity for the extraction of bioactive compounds. DESs (choline chloride-glycerol and choline-chloride-malic acid) were used for phenolic compound extraction and compared with traditional solvents such as water, ethanol, methanol, ethanol-water (50%), and methanol-water (50%). A higher concentration of phenolic compounds was achieved using choline chloride-glycerol than traditional solvents as an extraction solvent (7.98 mg eq of gallic acid/g of dry weight). In all the treatments, the antioxidant capacity was higher than 85%. The process variables (drying temperature, extraction time, and solvent/solid ratio) were optimized using choline chloride-glycerol as a solvent. It was found that a drying temperature of 67 &deg;C, an extraction time of 87 s, and a solvent/solid ratio of 60.5 mL/g allow maximizing the content of phenolic compounds and the antioxidant capacity of the extract

Microwave-Assisted Extraction of Phenolic Compounds from Pineapple Peel Using Deep Eutectic Solvents

Approximately half of the world’s pineapple production is marketed as a processed product, leading to the generation of a significant quantity of industrial waste, mainly composed of pineapple peels, cores, and crowns. This study evaluated deep eutectic solvents (DESs) for the assisted microwave extraction of phenolic compounds from pineapple peels and their antioxidant capacity. DESs are considered environmentally friendly solvents characterized by their low toxicity and high capacity for the extraction of bioactive compounds. DESs (choline chloride-glycerol and choline-chloride-malic acid) were used for phenolic compound extraction and compared with traditional solvents such as water, ethanol, methanol, ethanol-water (50%), and methanol-water (50%). A higher concentration of phenolic compounds was achieved using choline chloride-glycerol than traditional solvents as an extraction solvent (7.98 mg eq of gallic acid/g of dry weight). In all the treatments, the antioxidant capacity was higher than 85%. The process variables (drying temperature, extraction time, and solvent/solid ratio) were optimized using choline chloride-glycerol as a solvent. It was found that a drying temperature of 67 °C, an extraction time of 87 s, and a solvent/solid ratio of 60.5 mL/g allow maximizing the content of phenolic compounds and the antioxidant capacity of the extract

Physicochemical Properties of Guava Snacks as Affected by Drying Technology

Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires long operation times and the product characteristics are not desirable. In contrast, FD produces high quality products, but requires long processing times, high energy consumption and high operation costs. As an alternative, the Refractance Window&reg; (RW) drying is relatively simple and cheap technique. The objective of this study was to compare the effect of CD, FD and RW techniques, on the moisture content, water activity, color, porosity, volume change, vitamin C and carotenoids content in guava samples. The samples dried by RW required less time to reduce the moisture content and exhibited smaller changes in color than CD or FD. There were greater losses of carotenoids and vitamin C when drying by CD whereas RW had similar losses than FD. Lyophilized products exhibited minor change in volume and greater porosity. RW results in better retention of properties, compared with other drying techniques. Based on this, RW is a promising technique for the development of guava snacks

Factors Affecting the Time and Process of CMC Drying Using Refractance Window or Conductive Hydro-Drying

Intensive research on biodegradable films based on natural raw materials such as carboxymethyl cellulose (CMC) has been performed because it enables the production of transparent films with suitable barrier properties against oxygen and fats. Considering the importance of the production of this type of film at the industrial level, a scalable and continuous drying method is required. Refractance window-conductive hydro drying (RW-CHD) is a sustainable and energy-efficient method with high potential in drying this kind of compound. The objective of this study was to evaluate the factors (CMC thickness, heating water temperature, and film type) and radiation penetration depth that affect drying time and energy consumption. It was found that drying time decreased with increasing temperature and decreasing thickness. Similarly, energy consumption decreased with decreasing temperature and thickness. However, the drying time and energy consumed per unit weight of product obtained were equivalent when drying at any of the thicknesses evaluated. Film type had little effect on time and energy consumption compared to the effects of temperature and CMC thickness. The radiation penetration depth into the CMC was determined to be 1.20 ± 0.19 mm. When the thickness was close to this value, the radiation energy was better utilized, which was reflected in a higher heating rate at the beginning of drying