Sugaring-out-assisted aqueous two-phase extraction of fructooligosaccharides from yacon (Smallanthus sonchifolius)

Yacon roots contain about 80 wt% of β-(2-1)-fructooligosaccharides (FOS). This work aims to use water extraction method combined with sugaring-out technology to extract FOS from yacon. Most of FOS was extracted into the acetonitrile (ACN)-rich top phase, when yacon roots were dissolved in an ACN-yacon water extract mixture without extra sugar addition. Experimental results indicated that the partitioning behavior of FOS was closely correlated with the concentration of sugar in water extract of yacon, the system temperature and the volume ratio between ACN solution and yacon water extract.     

Effect of microwave-vacuum,ultrasonication, and freezing on mass transfer kinetics and diffusivity during osmotic dehydration of cranberries

The objectives of this study were (i) to evaluate moisture loss (ML), solids gain (SG), moisture loss rate (d(ML)/dt), solids gain rate (d(SG)/dt), effective moisture diffusivity (D_eM), and effective solids diffusivity (D_eS) during osmotic dehydration (OD), ultrasound-assisted osmotic dehydration (UA-OD), and osmotic dehydration of whole cranberries, preceded by microwave-vacuum pretreatment (MV?+?OD) or freezing/thawing treatment (F?+?OD ) and (ii) to use a mathematical model to predict moisture content ML_∞ and solids content SG_∞ in equilibrium state and the distribution of moisture and sucrose in whole cranberries during dehydration. Microwave-vacuum and OD treatments produced cranberries with the highest values of ML and SG (39.7 and 8.4?g 100?g?fresh?fruit^?1, respectively), d(ML)/dt and d(SG)/dt (76.9 and 8.5?h^?1, respectively), D_eM and D_eS (6.1 and 3.7?×?10^?10?m²?s^?1, respectively). Azuara’s and Peleg’s models adequately described the OD kinetics of whole cranberries in terms of ML and SG. The results indicate that the equilibrium values of ML_∞ and SG_∞ were not reached under the conditions specified in the present study.     

Apple osmotic dehydration described by three-dimensional numerical solution of the diffusion equation

ABSTRACT

In the present study, experimental data of osmotic dehydration kinetics of apple, cut into slices with parallelepiped shape, were simulated using two types of diffusion models. Model 1 considers the constant values of mass diffusivities and volume of the slices. Model 2, on the other hand, considers variable mass diffusivities and also the shrinkage of the product. The numerical solution of the three-dimensional diffusion equation in Cartesian coordinates was obtained through the finite volume method, with a fully implicit formulation and boundary condition of the first kind. Process parameters were determined by optimization using the experimental data sets, through the minimization of an objective function, called χ². The results of the osmotic dehydration kinetics were compatible with those of other studies found in the literature. Process temperature and osmotic solution concentration had influence on the phenomenon, but temperature was preponderant. A study was conducted on water and sucrose distribution during the osmotic dehydration. The results obtained through the mathematical model that considered the variable diffusivity and shrinkage showed greater adequacy to the experimental data.     

Experimental study of the application of edible coatings in pumpkin sticks submitted to osmotic dehydration

Osmotic dehydration (OD) improves the organoleptic characteristics of products; nevertheless, depending on the product, the incorporation of great amounts of solute can be undesirable to consumers. The application of hydrogel coatings would overcome this, acting as a barrier to solute entering the product. An alginate–calcium chloride barrier system (A-CC) was tested with or without pretreatment of Ca²⁺ as a firmness agent applied to pumpkin sticks. Products were dehydrated in sucrose and glucose solutions (40 and 60% w/w). Different parameters were estimated such as soluble solids uptake, water content, and weight reduction; in addition, texture and microstructural changes were studied. The A-CC configuration complies with the barrier function to solids uptake from the dehydrating solution in case of 60% of sucrose, allowing water exit from the vegetal matrix. The pretreatment with Ca²⁺ contributed to the retention of product firmness. Integrity, adhesiveness, and thickness of the A-CC system during the OD process were evaluated by environmental scanning electron microscopy (ESEM). In this case, the coating thickness reduction was according to the product weight reduction, indicating that the coated product was dehydrated as an integrated system.     

Effects of pretreatments on properties of microwave-vacuum drying of sweet potato slices

Abstract

Pretreatments of blanching (BL); osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (UD), and ultrasound-assisted osmotic dehydration (UO) were carried out for microwave-vacuum drying (MVD) orange- and purple-flesh sweet potato slices, and effects on their properties were investigated in this study. UO had improvements effects on water loss, solid gain, and relaxation time of the samples compared to other pretreatments. Low-field nuclear magnetic resonance results offered a view of water state concerning the effects of different pretreatments on sweet potato. UD treatment following by BL showed a long relaxation time corresponding to the weaker degree of bound hydrogen proton or the greater freedom degree of hydrogen comparing to other pretreated samples. Differential scanning calorimetry parameters appeared to be sensitive to pretreatments by increased Tg value compared to blanched sample. The value of Tg shows that it does not depend only of the water content but also on the experimental conditions (pretreatments). The dried sweet potato exhibited amorphous structures as evidenced by the X-ray diffractograms due to the BL treatment and MVD. Concentration of total phenolics and anthocyanins were high in purple sweet potatoes, whereas content of vitamin C and total carotenoid were high in orange ones. Application of UO is suitable for retention of bioactive compound and stability of MVD sweet potato slices.     

Dehydration of potato slices following brief dipping in osmotic solutions: Effect of conditions and understanding the mechanism of water loss

A novel variant of osmotic dehydration, named here as postdipping dehydration—where a material is dipped in a salt or sugar solution for a very short time followed by simple exposure to ambient conditions was explored with the aim of lowering water content of potato slices but at the same time not gain a high level of sugar/salt. The rate of water loss, which was rapid initially, was found to approach equilibrium. This article also explored whether the water loss process could subsequently be kick started once again, by employing a multistage process, where each stage consisted of osmotic solution dipping followed by ambient holding of the potato slices that had reached equilibrium in the earlier stage. Water loss values comparable to conventional osmotic dehydration could be achieved thus, but with significantly lower overall solid gain (<50%)—which can potentially yield a significantly healthy product option.     

Ultrasound-assisted osmotic process on quality of microwave vacuum drying sweet potato

The effects of pretreatment before microwave vacuum drying (MVD) on texture, color, expansion, rehydration, drying rate, microstructure, sensory evaluation, and other properties of sweet potato were investigated in this study. The pretreatment consisted in five processing conditions, using blanching; osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (US); ultrasound in distilled water before osmotic dehydration (US?+?OD), and ultrasound-assisted osmotic dehydration (USOD). Pretreatments of sweet potato before MVD have shown success in reducing drying time with US treatment relatively more effective regarding drying time than other treatments. Compared with other treatments, US showed the highest rehydration ratio values. The osmotic group pretreatment exhibited a pronounced effect on water loss and solid gain, improved the color, aroma, and taste of dried sweet potato, whereas sucrose impregnation resulted in a hard texture observed with OD sample. USOD samples had a higher expansion ratio, lower hardness and color difference values, appeared less cell damaged, and recorded better overall quality than the other samples. There was a slight difference between USOD and US?+?OD samples. Combining osmotic dehydration with ultrasound as a pretreatment can significantly accelerate the heat transfer rate, reducing the dried time accordingly and increasing energy efficiency.     

Texture analysis of dried papaya (Carica papaya L., cv. Maradol) pretreated with calcium and osmotic dehydration

The application of pretreatments before to convective drying improves the textural characteristics of minimally processed fruits. The aim of this work was to evaluate the texture of papaya (Carica papaya L., cv. Maradol) dried by convection pretreated with calcium hydroxide solutions and osmotic dehydration. Texture profile analysis was performed on fresh and dried cubes by convection at 70?°C not pretreated, as well as on those pretreated with calcium and osmotic solutions. During calcium immersion, the firmness increased, the TSS decreased, and the calcium gain was higher to low temperature. Water loss and solids gain were higher using high concentrations and temperatures during osmosis, resulting in lower values of moisture content and higher values ??of TSS. Calcium and osmotic pretreatments resulted in a product with intermediate moisture, stable color, firm, and minimal shrinkage. The modification of the papaya structure during all treatments caused a change in the textural characteristics. Statistical analysis of textural characteristics of dry cubes pretreated showed a significant difference (α?=?0.05) compared to fresh ones and not pretreated. The pretreatments formed a firm (outer) and a soft (inside) structure that reduced the shrinkage and the deformation of dry cubes and decrease the drying time up to 37% compared to dry cubes no pretreated.     

超声破乳脱水处理污油

利用超声波破乳脱水的基本原理,在驻波场下研究考察了超声参数对炼油厂污油破乳脱水的影响,证明了超声波分离油水乳状液的可行性和优越性。在同等条件下(相同的破乳剂量、温度等),沉降2h,超声处理污油脱水率可达91 7%以上,和单纯热沉降相比具有显著优势。实验中,较好的超声处理污油破乳脱水的工艺条件为声强0 66W/cm2、频率10kHz、作用时间5min、破乳剂用量0 375mg/g、温度70℃、沉降4h,可使污油脱水率在96 3%以上。     

Effect of sucrose concentration of osmotic dehydration pretreatment on drying characteristics and texture of peach chips dried by infrared drying coupled with explosion puffing drying

Effects of osmotic dehydration (OD) pretreatment on the texture characteristics of peach chips after combination drying were investigated. Peach slices were immersed into 100, 300, and 500?g/L sucrose solution for 4?h, respectively, at room temperature and then predried to a critical moisture content of 0.5?kg water/kg dry matter that was determined by the effective moisture diffusivity (D_eff) curves under infrared drying at 80°C. The peach chips were then dried using explosion puffing drying (EPD). The sucrose solution with lower concentration (100?g/L) would improve the drying rate (DR) of peach slices during infrared drying. However, sucrose solution with higher concentration (500?g/L) might affect water diffusion, resulting in lower drying rate. The changes of texture characteristics of dehydrated peach were ascribed to sucrose uptake during the impregnation step. The content and constitutes of soluble sugars in peach tissue, which was significantly affected by OD treatment, were also detected in the research. The results indicated that the combined infrared and EPD drying, in which OD with appropriate concentration (300?g/L) was applied as pretreatment, could improve the drying characteristics and texture of peach chips.     

Osmotic dehydration of blueberries pretreated with pulsed electric fields: Effects on dehydration kinetics,and microbiological and nutritional qualities

Fresh blueberries were treated by pulsed electric fields (PEF) at 2?kV/cm before osmotic dehydration in 70% cane sugar syrup. The changes in water loss, solids gain, populations of native microorganisms, antioxidant activity, contents of anthocyanins, predominant phenolic acids and flavonols, and total phenolics in blueberries were investigated after PEF pretreatment and during osmotic dehydration at 40°C. Compared with non-PEF-pretreated blueberry samples, PEF pretreatment reduced the osmotic dehydration time of blueberry samples from 120 to 48?h at target moisture content (3.0?g/g initial dry matter). No significant differences (p?>?0.05) in total phenolics, antioxidant activity, anthocyanins, and predominant phenolic acids and flavonols were observed between the PEF-pretreated and non-PEF-pretreated blueberry samples. The PEF-pretreated blueberry samples had lower microbial populations than those which were not subjected to PEF pretreatment. Regardless of pretreatment, decreases in anthocyanins, predominant phenolic acids and flavonols, total phenolics, and antioxidant activity in blueberries were observed during the osmotic dehydration process. The results demonstrate that PEF pretreatment significantly reduced the dehydration time and enhanced the microbiological quality of blueberries without affecting their nutritional quality.     

将超声破乳法用于炼厂污油脱水

;以含水量(体积分数)高达54%的中国石化镇海炼油分公司提供的污油为研究对象,在实验室条件下,采用超声波破乳技术进行重质污油的脱水研究.在确定破乳剂XDH和超声作用频率40kHz的条件下,考察了声场中超声波参数对污油脱水的影响.结果表明,超声辐照声强、超声辐照时间、超声辐照后的沉降时间及温度、破乳剂的用量都有其最佳值.实验样品在处理声场中,加入150mg/L破乳剂XDH,经413.5W/m2超声波辐照5 min,再在70℃水浴中沉降60 min,污油含水率降至0.2%(体积分数).     

雪莲果叶提取物降血糖口含片制备工艺研究

以雪莲果叶提取物的浸膏粉为主药,通过对比实验选择合适的辅料、配方及生产工艺制备雪莲果叶提取物降血糖含片,并对产品进行质量分析。研究结果表明,最佳的配方组合为:浸膏干粉50%、硬脂酸镁4‰、1∶1的甘露醇乳糖混合物48%、8%的淀粉浆适量、薄荷脑适量;最佳的工艺条件为:16目筛制粒,55℃干燥20 m in,16与18目筛整粒。在此配方及工艺条件下生产的产品各项指标均符合药典要求。     

Application of osmotic dehydration and microwave drying to strawberries coated with edible films

Osmotic dehydration (OD) is one of the conventional methods to increase the shelf-life of vegetables and fruits. However, the operating conditions can adversely affect the organoleptic and nutritional quality of fresh products due to the high sugar uptake during processing and the loss of water-soluble constituents to the osmotic medium. The application of edible films has attracted interest due to their ability to reduce the entry of solutes and simultaneously increase the removal of water during OD treatments. Microwave (MW) is one of the most effective emerging technologies to accelerate dehydration processes in vegetable matrices. This aspect is particularly relevant in strawberries, given its high content in bioactive and nutritional compounds. Thus, the aim of this paper was to assess the influence of edible film application (alginate–lactate) in strawberry slabs during combined OD-microwaves dehydration processes. Samples of 1?cm thickness were treated with sucrose solution (60°Bx, 40?°C, 4?h) and then were dehydrated in a microwave oven (1.2?W/g). The application of alginate–lactate edible films resulted in similar weight and water losses but lower solids gain compared to uncoated samples during OD treatment. OD pre-treated MW-dried strawberry slabs with moisture contents up to 0.15?kg dry basis were obtained after 100?min of MW drying. Besides, the effective diffusional coefficient (D_e) was estimated for MW drying process, values ranged from 4.5 to 8.8 10^?10 m²/s when shrinkage effect was considered, and from 1.1 to 2.3 10^?9 m²/s for constant thickness assumption.     

Influence of osmotic dehydration process parameters on the quality of candied pumpkins

The influence of osmotic dehydration process parameters on the efficiency of water loss and sucrose gain of pumpkins and the influence on the quality of the final product are essential for production of superior quality candied pumpkins. Mass transfer kinetics during osmotic dehydration of pumpkins were modelled by assuming Fickian diffusion of sucrose and water in unsteady state conditions, which described very well the experimental results for water loss and sugar gain. Water and sucrose effective diffusion coefficients increase significantly with temperature. Temperature and sucrose concentration had a significant influence on both water and sugar diffusion, increasing as the solution temperature increased. Significant increase in the effective water diffusivity and decrease in the sucrose effective diffusivity was observed when the sucrose solution concentration increased from 40 °Brix to 50 and 60 °Brix. From 50 to 60 °Brix, no difference in the effective diffusivities was observed. Candied pumpkins with higher sucrose content have a higher breaking stress, less breaking strain and lower work to fracture. Moreover, the product becomes harder and less elastic with increasing sucrose content, resulting in more brittle products, which seems to be related with reinforcement of the pumpkin cell wall matrix.     

The dehydration behavior and non-isothermal dehydration kinetics of donepezil hydrochloride monohydrate (Form I)

Powders of donepezil hydrochloride monohydrate (Form I) underwent isomorphic dehydration, losing 3% w/w water between 90% and 10% relative humidity (RH) without changing its powder X-ray pattern. Below 10% RH, additional dehydration occurred in conjunction with a reversible phase transition between the monohydrate state and a dehydrated state, with a 4.0% w/w loss to 0% RH. A combination of methods was used to understand the structural changes occurring during the desolvation process, including dynamic vapor sorption measurements, thermal analysis and powder X-ray diffraction. Form I showed the characteristics of the channel hydrate, whose non-isothermal dehydration behavior proceeds in two steps: (1) the loss of non-crystalline water adsorbed on the surface, and (2) the loss of one crystalline water in the channel. Dehydrated Form I is structurally similar to the monohydrate Form I. According to the heat of fusion and the crystal density criteria, the two crystal forms belonged to the univariant system, and the anhydrate (Form III) is stable. The dehydration kinetics was achieved from the TG-DTG curves by both the Achar method and the Coats-Redfern method with 15 frequently cited basic kinetic models. The dynamic dehydration processes for steps 1 and 2 were best expressed by the Zhuralev-Lesokin-Tempelman equation, suggesting a three-dimensional diffusion-controlled mechanism.     

Correction of moisture and sucrose effective diffusivities for shrinkage during osmotic dehydration of apple in sucrose solution

Shrinkage, moisture and sucrose effective diffusivities were correlated for infinite slab shape samples of apple during osmotic dehydration in sucrose solution. Experiments were carried out in the sucrose solutions of different concentrations (30%, 40% and 50%) and temperatures (30 °C, 40 °C and 50 °C). The two parameter model, developed by Azuara et al. (1992), was used to predict water loss and solid gain at equilibrium condition. Moisture and sucrose diffusivities were estimated by fitting the experimental moisture loss and solid gain data to the modified form of Fick's second law of diffusion, considering the shrinkage of the apples during osmotic dehydration. Results showed that the volume of the samples decreased linearly with water loss (WL) and weight reduction (WR). For above conditions of osmotic dehydration, effective diffusivities without considering the shrinkage were found to be in the range of 1.36 × 10⁻¹⁰ m²/s–2.00 × 10⁻¹⁰ m²/s, and those with considering the shrinkage were in the range of 0.87 × 10⁻¹⁰ m²/s–1.27 × 10⁻¹⁰ m²/s. The values of the effective diffusivities estimated by considering the shrinkage were smaller than those without considering this phenomenon.     

Mathematical modeling of moisture and solute diffusion in the cylindrical green bean during osmotic dehydration in salt solution

In this study, mass transfer during osmotic dehydration of cylindrical cut green beans in salt solution was investigated. The osmotic solution concentrations used were 10%, 20% and 26.5% (w/w) NaCl, osmotic solution temperatures used were 30 °C, 40 °C and 50 °C, the solution-to-green bean mass ratio was more than 20:1 (w/w) and the process duration varied from 0 to 6 hr. A two-parameter mathematical model developed by Azuara et al. (1992) was used for describing the mass transfer in osmotic dehydration of green bean samples and estimation of the final equilibrium moisture loss and solid gain. Effective radial diffusivity of moisture as well as solute was estimated using the analytical solution of Fick's second law of diffusion in the cylindrical coordinates. For above conditions of osmotic dehydration, moisture and salt effective diffusivities were found to be in the range of 1.776 × 10⁻¹⁰-2.707 × 10⁻¹⁰ m²/s and 1.126 × 10⁻¹⁰-1.667 × 10⁻¹⁰ m²/s, respectively. Moisture and solute distributions as a function of time and location in the radial direction were plotted by using the estimated equilibrium moisture and solute concentrations and also moisture and solute diffusivities.     

基于响应面的天然气三甘醇脱水装置用能优化

运用流程模拟软件HYSYS建立三甘醇(TEG)脱水装置的工艺模型,选择循环量qV、再生温度tr和三甘醇富液进塔温度ti作为主要参数,基于响应面方法(RSM)建立脱水装置能耗的二次显式模型。对响应面模型的显著性和三维图进行分析,结果表明:循环量、再生温度和富液进塔温度对装置能耗影响显著,影响程度为:循环量富液进塔温度再生温度;在对能耗的共同影响中,循环量和再生温度、循环量和富液进塔温度交互作用显著而再生温度和富液进塔温度间交互作用可以忽略。以吸收塔出口气体水露点满足GB17820—2012为约束条件,对模型进行最优化求解得到最优操作条件为:循环量400 L/h、再生温度199.8℃、富液进塔温度130℃,在此条件下理论能耗可下降48.3%,具有显著的节能效果。     

真空脱水在双氧水生产中的应用

真空脱水流程在国内双氧水行业由于其没有工作液的再生清洗作用,以及对其原理、工艺条件和优势缺乏研究,长期未受到应有重视。分析论证了双氧水装置真空脱水的原理,对工作液蒸气压理论计算和实际差异以及气相组分含量与理论值差异的原因给出了解释,提出工作液中游离水含量远高于溶解水的观点,推算确定了真空脱水适宜的温度为５２ ℃,压力为１０～１２ kＰａ。提出真空脱水在脱水效果、安全性、成本等方面明显优于碱塔脱水,在再生清洗方面可以通过抑制降解物的产生等得到有效解决。