Osmotic Agent Research Articles

Preparation Adlay and Black Sesame Seeds Extracts Using Osmotic Dehydration and Increasing the Stability of Extracts Using Encapsulation

Osmotic dehydration is an effective pretreatment method for preservation of herb, fruits and vegetables. This method can be conducted at low temperature so it can maintain the nutritional composition and food quality. In the present study, the effect of osmotic dehydration in 50, 60 and 70o Brix sugar solution at 40oC syrup temperature and drying air temperature (50, 60, 70 oC) on drying behavior of sample (adlay and black sesame seeds) were investigated before drying the sample and determined the percentage yield and total phenolic contents. All results from osmotic dehydration were compared with the soxhlet and maceration extraction methods. Among the three concentration of osmotic agents and drying temperature, percentage yield and total phenolic contents were higher at 70% concentration of osmotic agents and 60 oC air temperature which exhibited the total phenolic contents at 11.29±1.13 mg GAE/g extract and percentage yield of 4.36±0.34, respectively. From this osmotic dehydration, the surface morphologies of prepared bead containing sample had higher degree of surface smoothness and more spherical shape than non-sample bead and exhibited the encapsulation efficiency of micro-bead sample at 80.52 ± 0.36%.

Innovative technology of processing berries by osmotic dehydration

The present study is devoted to the influence of osmotic agent type and of its concentration on processing fresh berries with subsequent freezing. Freezing berries without preliminary protection destroys their texture, and during defreezing berries lose their consumer properties and vitamin content. The study describes the physical and chemical processes of osmotic dehydration: crystallization temperature; sucrose syrup concentration; changing the mass; frozen moisture amount; water activity; change of the mass fraction of mono-, disaccharides and vitamin C in the berries. As a result, crystallization temperature of dehydrated berries was calculated: from -1.1°C to -2.6°C (60°Brix) and from -1.7°C to -4.8°C (70°Brix). Frozen moisture amount was estimated at 83.2%-92.8% (60°Brix) and 52.2%-87.95% (70°Brix), water activity was 0.9756-0.9891 (60°Brix) and 0.9551-0.9838 (70°Brix). The obtained data allowed determining that the amount of monosaccharides in frozen berries which were preliminarily osmo-dehydrated with 70°Brix sucrose solution rose up to 20%, and the amount of vitamin C to 14.8% (compared with freshly frozen berries). Osmotic dehydration with sucrose solution of specified concentration protects the smooth texture of berries and preserves their organoleptic properties and valuable nutritional composition.

Development and Characterization of Controlled Porosity Osmotic Pump Tablets of Captopril

Background: The objective of the present study was to design a porous osmotic pump-based drug delivery system for the controlled release of captopril (Cap) which can maintain a constant therapeutic concentration, thus reducing dose-related side effects and dosing frequency. Methods: The study evaluated in vitro drug release for the controlled porosity osmotic pump tablet (CPOPT) of Cap. This in vitro drug release study investigated the influence of the tablet formulation variables such as the amount of mannitol, hydroxypropylmethylcellulose K4M (HPMCK4M), and polyvinyl pyrrolidone (PVP K-30) in the core and the concentration of cellulose acetate and polyethylene glycol 400 (PEG-400) in the coating solution. Results: It was found that the drug release was mostly affected by the amount of mannitol, HPMCK4M, and PVP K-30 in the core and the amount of cellulose acetate and PEG-400 in the coating solution. Conclusion: In general, the objective of the study was established by coating the core tablet containing osmotic and pore-forming agents. Therefore, the CPOPT of Cap could be a safe, effective, stable, and promising preparation in the future.

Desalination of saline water via forward osmosis using magnetic nanoparticles covalently functionalized with citrate ions as osmotic agent

ABSTRACT Forward osmosis is an emerging membrane technology in water desalination. In this study, desalination of saline water via forward osmosis was investigated using a new magnetic osmotic agent. For this purpose, Fe3O4 nanoparticles covalently functionalised with tri-sodium citrate was synthesised and characterised. The structural examinations revealed that the sodium citrate had been immobilised onto the magnetic nanoparticles. The highest water flux was obtained 17.1 L M−2 h (LMH) per 80 g L−1 osmotic agent solution against deionised water, while the ratio of salt flux to water flux was very low (0.088 g L−1). The osmotic solution was evaluated for saline water desalination using different concentrations of sodium chloride (NaCl) as feed solutions. The average water fluxes of 6.2, 4.5, and 2.7 LMH was obtained for 0.1, 0.2, and 0.5 M salt solutions, respectively. The magnetic osmotic agent was separated by a magnet and re-used for several times without considerable decrease in the water flux.

Preparation of Nifedipine Push-Pull Osmotic Pump Tablets

This study aims to investigate the influence of the formulation factors on the drug release kinetics, thereby selecting the compositions of extended-release nifedipine tablet based on the similarity coefficient f2 obtained when compared with Adalat LA tablet. The formulation factors such as: molecular weight of the polyethylene oxide (PEO) and osmotic agent amount in drug layer and push layer, semi permeable membrane thickness (estimated by coating weight gain), orifice size, type of plasticizers and ratios of coating polymer to plasticizer in semipermeable membrane were evaluated. It was found that developed tablets were able to deliver nifedipine in an approximate zero-order manner up to 20 hours and drug release profile of developed tablets was similar to that from Adalat LA tablets. The developed tablet contained: PEO N10, PEO 303 in drug layer and push layer, respectively; percentages of osmotic agent in drug layer and push layer were 10% and 30%, respectively; weight gain of semipermeable coating was 12%; and orifice size was 0.8 mm.
 Keywords
 Nifedipine, GPKD, push-pull osmotic pump, PEO, Tlag.
 References
 [1] Vietnamese National Drug Formulary Council, Nifedipine, Vietnamese National Drug Formulary, 2nd edition, Medical Publising House, Hanoi, 2018, pp. 1056-1058 (in Vietnamese).[2] A. Nokhodchi, M.N. Momin, J. Shokri, et al., Factors affecting the release of nifedipine from a swellable elementary osmotic pump, Drug Delivery, 15 (1) (2008) 43-48. https://doi.org/10.1080/10717540701829028[3] R.K. Verma, D.M. Krishna, S. Garg, Formulation aspects in the development of osmotically controlled oral drug delivery systems, Journal of controlled release 79 (1-3) (2002) 7-27. https://doi.org/10.1016/s0168-3659(01)00550-8.[4] The United States Pharmacopeial Convention, Nifedipine Extended-Release Tablets, The United States Pharmacopeia, 41st edition, United Book Press, Baltimore, 2018, pp. 2938 - 2944.[5] V. Malaterre, J. Ogorka, N. Loggia, et al., Approach to design push–pull osmotic pumps, International Journal of Pharmaceutics 376 (1–2) (2009) 56-62. http://dx.doi.org/10.1016/j.ijpharm.2009.04.015.[6] S. Missaghi, P. Patel P, Farrell T. P., et al., Investigation of critical core formulation and process parameters for osmotic pump oral drug delivery, AAPS PharmSciTech 15 (1) (2014) 149-160. http://doi.org/10.1208/s12249-013-0040-4.[7] V. Malaterre, H. Metz, J. Ogorka , et al., Benchtop-magnetic resonance imaging (BT-MRI) characterization of push-pull osmotic controlled release systems, J Control Release 133 (1) (2009) 31-36. http://doi.org/10.1016/j.jconrel.2008.09.007.[8] Z. Zhang, W. Li, S. Nie, et al., Overcome side identification in PPOP by making orifices on both layers, International journal of pharmaceutics 371 (1-2) (2009) 1-7. http://dx.doi.org/10.1016/j.ijpharm.2008.12.006[9] C. Wu, Z. Zhao, Y. Zhao, et al., Preparation of a push–pull osmotic pump of felodipine solubilized by mesoporous silica nanoparticles with a core–shell structure, International Journal of Pharmaceutics,475 (1-2) (2014) 298 - 305 . http://dx.doi.org/10.1016/j.ijpharm.2014.08.033.[10] V. Patel, A. Chudasama, M. Nivsarkar, et al., Push-pull osmotic pump for zero order delivery of lithium carbonate: Development and in vitro characterization, Pharmaceutical development and technology, 17 (3) (2012) 375-382. http://doi.org/10.3109/10837450.2010.542577.[11] C.N. Patra, S. Swain, J. Sruti, et al., Osmotic drug delivery systems: Basics and design approaches, Recent Patents on Drug Delivery & Formulation 7(2) (2013) 1 - 12. http://doi.org/10.2174/1872211311307020007.
 

Morpho‐physiological, biochemical and isotopic response of tall wheatgrass populations to salt stress

AbstractTall wheatgrass [Elymus elongatus subsp. ponticus (Podp.) Melderis] is a C3 grass native from dry or saline habitats in SE Europe. The aim of this study was to better understand response mechanisms of populations from different origins to salinity and to provide new tools to select germoplasm with high salinity tolerance. Four populations (P3‐P4‐P5‐P9) were irrigated with five solutions of increasing salinity (Salt: 0–0.1–0.2–0.3–0.4 M NaCl) and evaluated in pots in a greenhouse. Two experiments were carried out, a short 40‐day long experiment with vegetative plants, and a longer 85‐day long one with plants that underwent vegetative‐reproductive stage. No evidence was found of an interaction between population and salt. Morpho‐physiological, biochemicals, isotopic and productive variables were differently affected by increasing salinity and were also different among populations. Proline, Na+ and Cl− consistently appeared to function as osmotic agents. P5 showed the highest biomass in the 85‐day experiment and had the highest leaf length, tiller density, water use efficiency and δ13C isotope; and the lowest Cl− concentration and evapotranspiration rate. However, P5 showed the lowest biomass in the 40‐day experiment, suggesting that duration of the stress is an important aspect to consider when selecting germoplasm for tolerance to salinity. Differences among populations in growth strategies and physiological mechanisms could be related to their origin environment.

Osmotic dehydration and convective drying of kiwifruit (Actinidia deliciosa) – The influence of ultrasound on process kinetics and product quality

The aim of this study was to assess the impact of ultrasound on two subsequent processes – initial osmotic dehydration and convective drying of kiwifruit (Actinidia deliciosa). The effect of ultrasound (at a frequency of 25 kHz) was assessed both in terms of process kinetics and product quality. During the study, three different osmotic agents were used – erythritol, sorbitol, and sucrose – in an aqueous solution at a concentration of 50% (w/w). The essential kinetic parameters were analyzed – water loss and increase of dry matter during osmotic dehydration, and evolution of moisture content and temperature of samples during convective drying (drying curves). Product quality was assessed on the basis of color, water activity, and content of relevant bioactive components – polyphenols and carotenoids. It was found that the application of ultrasound during osmotic dehydration resulted in higher water loss and solid gain. This surely results from the phenomena occurring during the propagation of the elastic waves in the liquid medium (mainly related to cavitation) and enhancement of the mass transfer. The use of ultrasound during convective drying also had a positive effect on the kinetics of this process. In most cases, during the ultrasonically assisted drying operations, a significant increase in drying rate was observed, leading to a reduction in drying time. This may be due to the intensification of both heat and mass transfer as a result of the mechanical and thermal effects of ultrasound. The assessment of product quality showed that the use of sugar alcohols was a good alternative to sucrose, and ultrasound-assisted convective drying increased the retention of valuable carotenoids and polyphenols. Moreover, in all dried kiwifruit slices, water activity was below 0.6, which can guarantee the microbiological stability of the tested samples.

TEXTURE ANALYSIS OF STARFRUIT (Averrhoa carambola) CHIPS PRE-TREATED WITH GLUCOSE SYRUP AND OSMOTIC DEHYDRATION

Osmotic dehydration (OD) of starfruit chips by glucose syrup was chosen as the osmotic agent (OA) in this study as it is believed to confer a desirable result in the final product. As in this study, the concentration of glucose syrup that was used is 30, 40 and 50°Brix with soaking temperature of 20°C to 60°C and soaking time of 20 min to 60 min. The result showed that higher water loss and lower solid gain of starfruits obtained as the higher temperature and glucose syrup concentrations were used. Meanwhile, processing of osmo-dried starfruits into chips were done by stir frying with canola oil. The use of glucose syrup with concentration of 50°B, 60°C temperature and 60 min soaking time produced the highest hardness and crispness of starfruit chips with the lowest moisture content. Test of significance (p<0.05) in results obtained from this study were determined using Minitab 18 software as one-way Analysis of Variance (ANOVA) and Tukey-Test. In general, OD pre- treatment could be proved as an effective technique for food industries to develop fried starfruit chips with improved texture quality.

Flavonoid enrichment of fresh-cut apple through osmotic dehydration-assisted impregnation

PurposeInclusion of bioactive compounds in food products is promising for developing novel functional food products. The feasibility of incorporating flavonoids and low-calorie sugar substitutes in fresh-cut apple through osmotic dehydration (OD) was investigated.Design/methodology/approachThe impregnation of quercetin and fisetin in apple cubes was tested. The effects of different osmotic agents, sucrose and sorbitol:mannose, on the water loss (WL) and sugar gain of the samples were studied at 25 and 40 °C for eight hours.FindingsTemperature was a significant factor in the mass transfer kinetics, that is to say, higher temperatures resulting in higher rates. The molecular weight of the solutes in the osmotic solution also affected the OD kinetics and flavonoids uptake, as well as the physico-chemical quality.Originality/valueOverall, the results indicate that OD using alternative low-calorie and health-promoting solutes can be an effective treatment to simultaneously enrich fresh-cut apples with senolytic flavonoids, therefore presenting a great potential for a novel functional food product.

EVALUATION OF MASS TRANSFER DURING OSMO-CONVECTIVE DRYING OF BENINCASA HISPIDA CUBES IN SALT SOLUTION USING REGRESSIONAL-DESIRABILITY METHOD

Regressional-desirability approach in Box-Behnken response surface design was employed in this study to examine and optimize the osmotic dehydration process of Benincasa hispida cubes by impregnating in salt solution as an osmotic agent. The effect of independent parameters such as, concentration of solution (1-5%), sample to solution ratio (1:5-1:15 g/ml), temperature of osmotic solution (30-50℃) and time of immersion (30-180 min) on the weight reduction (WR), solid gain (SG), water loss (WL), rehydration ratio (RR) and shrinkage (SH) were studied. Second order polynomial mathematical models were developed for the responses and all the independent process variables have considerable consequence on the responses. The optimal dehydration process condition was found by regressional-desirability method and were: osmotic solution concentration of 2.73%, sample to solution ratio of 1:14 g/ml, osmotic solution temperature of 50℃ and osmotic dehydration time of 179 minutes with the mass transfer and quality properties such as weight reduction of 24.59%, solid gain of 7.69%, water loss of 32.28%, rehydration ratio 11.43%, shrinkage 8.58% and overall acceptability 8.19. The optimized samples were subjected to convective drying in cabinet tray dryer at different drying air temperatures (40, 50 and 60℃). The results indicated that the osmotic pre-treatment of the samples using salt solution was better in terms of water removal and reduction in the processing time when combined with convective drying process. Also, the quality of the final product was found to be good for the osmo-convective dried product using salt solution.

HYPERGLYCEMIC CRISIS FUNCTIONING AS HYPEROSMOTIC RESCUE IN A PATIENT WITH ISCHEMIC CEREBELLAR STROKE

SESSION TITLE: Medical Student/Resident Critical Care Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Cerebral injury is a rare complication of hyperglycemic crisis, typically occurring within 3-12 hours of treatment initiation. It is presumed to be a result of aggressive fluid resuscitation and rapid serum osmolality changes following initiation of insulin therapy. Incidence is less than 1% in children with only limited cases reported in adults. We report a rare case of hyperglycemic hyperosmolar state (HHS) secondary to acute pancreatitis and methamphetamine abuse in a patient with concomitant ischemic cerebellar infarct who rapidly deteriorated following corrective therapy. We propose a potential pathophysiological explanation of her presentation, highlighting the challenges in management. CASE PRESENTATION: A 54-year-old female with poorly controlled type-2 diabetes mellitus (DM) noncompliant with insulin therapy, hypertension, and methamphetamine abuse presented with acute encephalopathy and gastrointestinal distress. She was hypertensive and tachycardic on arrival in no respiratory distress. Labs were significant for profound hyperglycemia with blood glucose of 912 mg/dL, bicarbonate 19.5 mmol/L, anion gap 24 mmol/L, beta-hydroxybutyrate of 0.98 mmol/L, lactate 9.2 mmol/L, lipase 2462 U/L, and balanced electrolytes. Toxicology screen was positive for methamphetamine. ABG on room air showed normal range pH. CT head revealed a 2.6 cm region of hypoattenuation in the inferior cerebellum suggestive of acute ischemic infarct. She was given IV fluid followed by insulin infusion and admitted to the ICU. Shortly after, she became rapidly hypoxemic with bradypnea requiring rapid sequence intubation, followed by sudden bradycardia and ultimately fatal PEA arrest. DISCUSSION: To our knowledge, there has never been a reported case of concomitant HHS and acute cerebral ischemia in adults. Although MRI was unable to be performed, we suspect our patient suffered rapid intracranial pressure elevation as evidenced by development of Cushing triad. Patients with ischemic cerebellar infarcts are at high risk for reactive cerebral edema. Glucose is a natural osmotic agent, increasing serum tonicity, and may have provided an ironic therapeutic benefit. Rapid correction of her hyperosmolar state with insulin therapy in conjunction with aggressive fluid resuscitation, likely precipitated sudden intracellular fluid influx and subsequent herniation. Post-stroke hyperglycemia is a common physiological occurrence and may have served as a potential hyperosmotic rescue measure in our patient. CONCLUSIONS: Cerebral edema is a rare but potentially fatal complication of hyperglycemic crisis therapy. Risk is significantly elevated in those with acute ischemic infarcts and careful correction of glucose and electrolytes should be attempted. Reference #1: Varela D, Held N, Linas S. Overview of Cerebral Edema During Correction of Hyperglycemic Crises. Am J Case Rep. 2018;19:562-566. DISCLOSURES: No relevant relationships by Helen Li Mitchell, source=Web Response No relevant relationships by Sushant Soni, source=Web Response No relevant relationships by Shawnt Tosonian, source=Web Response No relevant relationships by Nathaniel Wise, source=Web Response No relevant relationships by Tommy Zaharakis, source=Web Response

Equimolar doses of hypertonic agents (saline or mannitol) in the treatment of intracranial hypertension after severe traumatic brain injury.

Background:Mannitol and hypertonic saline (HTS) are effective in reducing intracranial pressure (ICP) after severe traumatic brain injury (TBI). However, their efficacy on the ICP has not been evaluated rigorously.Objective:To evaluate the efficacy of repeated bolus dosing of HTS and mannitol in similar osmotic burdens to treat intracranial hypertension (ICH) in patients with severe TBI.Methods:The authors used an alternating treatment protocol to evaluate the efficacy of HTS with that of mannitol given for ICH episodes in patients treated for severe TBI at their hospital during 2017 to 2019. Doses of similar osmotic burdens (20% mannitol, 2 ml/kg, or 10% HTS, 0.63 ml/kg, administered as a bolus via a central venous catheter, infused over 15 minutes) were given alternately to the individual patient with severe TBI during ICH episodes. The choice of osmotic agents for the treatment of the initial ICH episode was determined on a randomized basis; osmotic agents were alternated for every subsequent ICH episode in each individual patient. intracranial pressure (ICP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) were continuously monitored between the beginning of each osmotherapy and the return of ICP to 20 mm Hg. The duration of the effect of ICP reduction (between the beginning of osmotherapy and the return of ICP to 20 mm Hg), the maximum reduction of ICP and its time was recorded after each dose. Serum sodium and plasma osmolality were measured before, 0.5 hours and 3 hours after each dose. Adverse effects such as central pontine myelinolysis (CPM), severe fluctuations of serum sodium and plasma osmolality were assessed to evaluate the safety of repeated dosing of HTS and mannitol.Results:Eighty three patients with severe TBI were assessed, including 437 ICH episodes, receiving 236 doses of HTS and 221 doses of mannitol totally. There was no significant difference between equimolar HTS and mannitol boluses on the magnitude of ICP reduction, the duration of effect, and the time to lowest ICP achieved (P > .05). The proportion of efficacious boluses was higher for HTS than for mannitol, although which showed a slight difference (p = 0.207), as was the increase in serum sodium (P = .038). The serum osmolality increased immediately after osmotherapy with a significant difference (P = .017). No cases of CPM were detected.Conclusion:Repeat bolus dosing of 10% HTS and 20% mannitol appears to be significantly and similarly effective for treating ICH in patients with severe TBI. The proportion of efficacious doses of HTS on ICP reduction may be slightly higher than mannitol.

Forward osmosis with direct contact membrane distillation using tetrabutylphosphonium p-toluenesulfonate as an effective and safe thermo-recyclable osmotic agent for seawater desalination

A phosphonium-based ionic liquid (IL) with lower critical solution temperature (LCST) property was assessed as a reusable draw solution (DS) for forward osmosis (FO). Tetrabutylphosphonium p-toluenesulfonate ([P4444]TsO) was successfully synthesized by neutralization reaction. Characterization results reveal its ability to generate sufficient osmotic pressure (14–68 bars for 0.5–2 M DS) to create a gradient across the FO membrane. Its thermal, physico-chemical and other colligative properties are favorable for its application as an osmotic agent. The LCST behavior of [P4444]TsO was found reversible and its phase separation from water can be done above its cloud point temperature Tc ∼57 °C. In vitro cytotoxicity tests from LDH and MTT assay reveal that it can be safely used as DS at an effective concentration EC30 ∼57 mg L−1 as its non-toxic level. Results from FO operations demonstrate that 2 M [P4444]TsO DS can effectively treat saline feed like seawater (0.6 M NaCl) with reasonable Jv = 1.35 ± 0.15 L m−2h−1, low Js = 0.0038 ± 0.00049 mol m−2h−1, and considerably low specific solute flux (Js/Jv ∼ 0.0028 mol L−1). After FO, ∼98% of [P4444]TsO was precipitated by heating the DS at 60 °C and conveniently reused with consistent FO performance. Direct contact membrane distillation (DCMD) was found effective in removing the residual 2% [P4444]TsO in the DS supernatant to finally produce high-quality effluent with concentrations way below the EC30 limit. Cost estimates for the entire process reveal the potential of FO combined with thermo-cyclic [P4444]TsO regeneration with DCMD for desalination application.

Çocuklarda İki Bağırsak Hazırlık İlacının Etkinlik ve Kullanılabilirliğinin Karşılaştırılması: Polietilen Glikol ve Sodyum Fosfat

Adequate bowel cleansing with a good patient tolerability is important for high-quality and safe colonoscopy. We aimed to compare the efficacy and tolerability of an osmotic agent, polyethylene glycol (PEG) and a less frequently used stimulant agent, sodium phosphate (NP) for pediatric patients. We analyzed the records of pediatric patients who underwent colonoscopy and used either PEG or NP for bowel cleansing between January 2016 and December 2019. The patient tolerability of bowel preparation was assessed using a patient questionnaire that consisted of acceptance and adverse events, recording abdominal pain, nausea, vomiting, dizziness and severity of these symptoms. The quality of bowel preparation was assessed according to the Ottawa scale, including cleanliness and fluid quantity. The colonoscopic video records were retrospectively and blindly evaluated for Ottawa scale. There were a total of 145 patients (65 boys, 44.8%) with a mean age of 12.3±4.2 years. PEG was used in 93 patients (64.1%), while NP was used in 52 patients (35.9%). The mean age of the patients was significantly lower in PEG group (11.2±4.6 years) when compared to NP group (14.2±2.7 years) (p<0.0001). The patients who used PEG had significantly better tolerance without any complaints when compared to the patients who used NP (49/93 patients (52.7%) vs 14/52 patients (26.9%), respectively, p=0.003). Regarding the severity of symptoms in patients who had adverse events, the NP group had significantly more frequent moderate-severe side effects when compared to PEG group (15/52 patients (28.8%) vs 15/93 patients (16.1%), respectively, p=0.014). One of the children in NP group had severe hyperphosphatemia, which required fluid resuscitation. Regarding the efficacy of the preparations, 39/93 (41.9%) of the patients in PEG group had required wash and suctioning in any segments of the colon, this ratio was significantly lower in NP group (12/52 (23%)), (p=0.029). The Ottawa bowel preparation quality score in right colon and total Ottawa scale rating was significantly better in NP group when compared to PEG group (p=0.009 and 0.034, respectively). The Ottawa scores in mid and rectosigmoid colons were not significantly different between two groups. As conclusion, NP is more efficient in bowel cleansing when compared to PEG. But PEG had less frequent moderate-severe side effects compared to NP. Additionally, NP should be carefully used in selected cases where other bowel cleansing methods cannot be used, because of the severe side effects like hyperphosphatemia in children.

Modeling of solute transport inside plant tissue during osmotic dehydration of apple

The accumulation of solutes on the food surface has resulted in notable contradictions between data resulting from modeling and information observed experimentally. Hence, the mechanisms involved in the transport of solutes in the plant tissue during osmotic dehydration (OD) have not been well documented. The purpose of this study was to analyze solute concentration at different depths of osmotically dehydrated apple cylinder with the use of a conventional (sucrose) and a non-conventional (stevia) osmotic agent. Solute concentration was modeled by Fick's law in order to identify the thicknesses within the tissue where the solute is transferred under a diffusive mechanism. Samples were dehydrated in sucrose (30 and 50°Brix) and stevia (3 and 6% w/w) aqueous solutions. Samples were cut in five slices (0.5, 2, 4, 7, 10 mm in z direction) from the surface to the food center. Sample properties such as: water loss, solute gain, moisture content, solute concentration and effective diffusivity coefficients at different tissue depths and time periods of dehydration process were determined. Results showed the concentration of solutes was higher in the surface than the center for both osmotic solutions: stevia and sucrose. Fick model did not allow an adequate description of the experimental data in the area of solutes accumulation, suggesting that transfer of solutes on the tissue surface is governed by other transport mechanism different from diffusion. This result opens new ways for future research of the solutes transport within plant tissue. Under this approach, the surperficial impregnation of solutes at the surface and a diffusive phenomenon inside the sample center could be considered.

Dichloromethane evaporative behavior during the solidifying process of ovalbumin-loaded poly (DL lactic-co-glycolic acid) microparticles

The purpose of this study is to develop an analytical method for determining the evaporative behavior of dichloromethane (DCM) during the solidifying process of poly(DL lactic-co-glycolic acid) (PLGA) in the preparation of ovalbumin-loaded microparticle (OVA-MP) with double emulsion solvent extraction method. The time courses of DCM levels in the external phase and total mixture were determined by a gas chromatography (GC) method combined a headspace sampler. Samples were spiked with an internal standard carbon tetrachloride, prior to mixing with a large volume of chloroform. The retention times of carbon tetrachloride, DCM and chloroform were 2.6, 2.8 and 3.3 min, respectively. The analytical method had a minimum quantitative concentration of DCM 7.3 mM and good linearity from 7.5 to 75 mM with coefficient of variations 1.2-3.9%. Four formulations containing NaCl (0-5%) and urea, an osmotic agent to adjust osmolarity at 1240 mOsm/kg, were investigated. The disappearance of DCM levels in total mixtures of four formulations were described as a function of time by zero-order (0-15 min) and first-order (after 15 min) kinetics. During the initial 15 min, these formulations had almost identical zero-order rate constants, 2.30-2.63 mmole/min. After 15 min, formulation with 5% NaCl (F4) showed a significant lower value of rate constant (0.193 min-1) in comparison with other formulations using the lower amounts of NaCl (0.288-0.367 min-1). It indicated tha the surface characteristic of the F4 OVA-MP was different from other formulations by forming a crust-like structure to inhibit the efflux of DCM from the inner layer. In conclusion, we established a rapid and convenient GC approach without the need for sample pre-treatment for determining DCM levels during the solidifying process of microparticles. The analytical method could be applied to further assess the relationship between DCM level and formulation factors of drug-loaded microparticles.

Osmotic dehydration of apple and pear slices: color and chemical characteristics

Abstract Osmotic dehydration is the pre-treatment method of preservation the fruits and vegetables to increase their shelf life. This method consists of immersing fruits and vegetables in concentrated solutions of salt or sugar. The effect of osmotic dehydration was investigated on the color and chemical characteristics of dehydrated fruits (apple and pear) in fructose osmotic solutions. Difference in CIE-LAB, chroma - C* and hue angle H* were performed with a Chroma Meter CR-400/410. Apple (Malus domestica ‘Jonathan’) and sweet autumn pear variety (Pyrus comunis) were osmotically dehydrated in three aqueous solution of fructose (40, 60 and 80%), during 3 h of process at temperatures of 20 °C, with fruit/osmotic agent ratio of 2:1. Water loss and solids gain showed significant differences depending on the concentration of the osmotic agent and process time. The use of highly concentrated osmotic solutions induced losses of phenolic content (TPC) and ascorbic acid in the sliced apples and pears. Fructose concentration and osmosis time induce significant increase of a* and b* colorimetric parameters but did not affect the lightness (L*) of pear slices.

Effect of concentration of osmotic solution on: Aloe vera

Aloe vera, a tropical and subtropical plant belonging to the Liliaceae family, contains a transparent mucilaginous jelly known as Aloe vera gel. The drying of osmo air consists of preheating the sample by osmotic dehydration and subjecting it. Osmotic dehydration is incomplete removal by osmotic agent of water from a food product. Initial moisture content of Aloe vera gel was found to be 98.8% and minimum moisture content of dried Aloe vera was found to be 3.01% (wb) after 12hr of osmo-air dehydration treatment. Osmotic dehydration of Aloe vera reduces the initial moisture content of 98.8% to 48.9% at 300 brix sugar concentration whereas reduction from 98.8% to 25.14% was observed in case of 70˚ brix. An intermediate value of reduction to 36.61% wb was observed in case of osmotic treatment at 500 brix. In osmotic treatment at 30o brix the drying rate decreased from 0.2838, 0.1741,0.1233, 0.1138 and 0.0911g/min from 1st to 5th hour, whereas in 70o brix drying rate obtained was found to be highest in the first hour 0.6268 g/min and starts gradually decreasing from 0.6268, 0.2176, 0.1238, 0.0970 and 0.0505 g/min within five hours.

Combined Osmotic and Air Dehydration for the Production of Shelf-Stable White Cheese

The research targeted on the production of an innovative shelf-stable cheese of high quality, through the combinatory effect of osmotic dehydration (OD) as pretreatment and conventional air-drying. The optimum OD processing conditions (process time/temperature, concentration of osmotic solution, food to OD agent ratio) were determined through a kinetic study of the effect of OD parameters on the water activity (aw) and water/solid transport phenomena, organoleptic and quality characteristics of the white cheese in cubes. Through Fick’s second law for mass transfer, water and solid diffusion coefficients were determined. Taking into consideration the aw, the quality, and organoleptic characteristics of the final product, the optimum OD conditions were selected as 15 °C process temperature, food to osmotic agent ratio 1:4 (w/w), concentration of osmotic agent 65% to glycerol, and treatment time 30 min. The final moisture and aw of the OD-treated product were calculated as 40% and 0.88, respectively. The time of OD-pretreated product for air-drying at 40, 55, and 67 °C to 5% residual moisture was reduced by 35, 51, and 65% respectively. The selected air-drying conditions were 67 °C for 4 h. Quality parameters of the final white cheese product were studied during its storage at 15–40 °C, and the shelf life was estimated as 6 months at ambient temperature.

Design Rationale for Stimuli-Responsive, Semi-interpenetrating Polymer Network Hydrogels-A Quantitative Approach.

Stimuli-responsive semi-interpenetrating polymer network (semi-IPN) hydrogels form an important class of polymers for their tunable properties via molecular design. They are widely investigated for a diverse range of applications including drug delivery, sensors, actuators, and osmotic agents. However, in-depth studies on some of the critical design principles affecting diffusion/leaching of linear polymer from semi-IPN hydrogels are lacking. Herein, for the first time, by preparing a series of model semi-IPN hydrogels based on thermally responsive poly (N-isopropyl acrylamide) (PNIPAM) network and linear poly(sodium acrylate) (PSA), a systematic and quantitative study concerning linear polymer chain retention and swelling/deswelling kinetics is reported. The study shows that PSA retention is significantly affected not only by PSA molecular weight and concentration, but also by polymerization temperature, which could be linked to homogeneity and internal morphology of the hydrogel. Surprisingly, there is no obvious influence of crosslinking density of PNIPAM network toward PSA retention, while faster swelling and deswelling at higher crosslinking density are observed in terms of swelling rate constant and deswelling activation energy. These findings offer new insights on the factors affecting structural and physicochemical properties of such semi-IPN hydrogels, which should in turn serve as a general guideline for materials design.