JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2007
E. MORALES SANCHEZ
ABSTRACT In the present work, rice starch was studied by differential scanning calorimetry (DSC) and electrical conductivity as a function of temperature. The gelatinization temperature was calculated using both methods. Three stages of electrical conductivity were found. When the logarithm of conductivity was plotted versus temperature, the data have been well adjusted to the linear equation, indicating that a model for conductivity may be created using an Arrhenius-type expression to obtain kinetic parameters such as onset, peakset, endset temperatures and gelatinization energy (Eg). The conductivity Eg was calculated and compared to the enthalpy H calculated from the DSC data. It was found that Eg and enthalpy are similar processes. We conclude that electrical conductivity is an alternative method for the study of starch,water mixtures. PRACTICAL APPLICATIONS This research provides a new methodology to obtain kinetic parameters such as temperature of the beginning, medium and ending of gelatinizaiton, which are important for determining the cooking range needed to obtain desired characteristics in a processed starch-containing food. [source]

PROPERTIES of CROSS-LINKED STARCH PRODUCED IN A SINGLE SCREW EXTRUDER WITH and WITHOUT A MIXING ELEMENT

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2004
M. SEKER
ABSTRACT Starch was extruded with sodium hydroxide and sodium trimetaphosphate in order to cross-link it in a single-screw extruder with and without a mixing element at constant screw speed of 90 rpm in the first set of experiments and at similar mean residence time controlled by screw speed in the second set of experiments. For the screw without mixing element in the second set of experiments, screw speed was adjusted to give the similar residence time as the single-screw extruder with mixing element at 220 rpm. Phosphorus content and pasting curves of extrudates showed that starch was cross-linked during extrusion. Replacing the screw without mixing element by the screw with mixing [source]

IMPROVED VIABILITY OF SPRAY DRIED BREWER'S YEAST BY USING STARCH (GRITS) AND MALTODEXTRIN AS PROCESSING AIDS

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2000
GUADALUPE LUNA-SOLANO
ABSTRACT Active dry brewer's yeast was prepared by spray drying (Tout 50 and 60C). Addition of processing aids to the yeast cream was necessary in order to dry at these temperatures. Corn starch (grits) and maltodextrins (DE-6) two levels of additions (10 and 20%) were used as processing aids. Statistical analyses proved that processing aids concentration, air outlet temperature and rotor speed had significant effects on yeast viability. Dried samples could be preserved at least 4 months stored at 5 and 25C with a loss of 1 and 2 log cycles of viable cells, respectively. [source]

STUDY OF SAGO STARCH (METROXYLON SAGU) GELATINIZATION BY DIFFERENTIAL SCANNING CALORIMETRY

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2001
YAAKOB B. CHE MAN
Differential scanning calorimetry (DSC), at various heating rates (1,30C/min) and water:starch ratios (0.1:1,4:1), was used to study gelatinization phenomena of sago starch. The results showed that the gelatinization temperature and enthalpy (, H) of starches in excess water were 60,77C and 15.5,15.8 J/g, respectively. , H of gelatinization remained substantially the same at excess water contents, but decreased significantly beyond a water:starch ratio of 1.3:1. A single endothermic transition (G) that transformed into a double endotherm (G and M1) and only M1 occurred, respectively, at excess, intermediate and limited water contents. At 50% water content, evidence of the M1 endotherm was observed, and 85C represented the effective conclusion temperature (Tm) at the end of melting for sago starch. The experimental data were treated thermody-namically by applying an equation describing phase transitions of semi-crystalline polymers. The calculated value for the melting point of the undiluted polymer (Tm) was 432 K (R2= 0.96). [source]

EVALUATION OF ISOMALT AND HYDROGENATED STARCH HYDROLYSATE IN SUGARLESS CARAMEL POPCORN,

JOURNAL OF FOOD QUALITY, Issue 1 2002
L.G. BECK
Five formulations of sugarless caramel popcorn sweetened with different proportions of hydrogenated starch hydrolysate and isomalt were developed. Control and test products were evaluated for changes in physical, chemical and sensory properties over a 3-month storage period at 33C and 50% humidity. Moisture content and water activity values increased for all products, but color values did not change with time. Texture compressibility measurements were highly correlated with liking of texture values gathered from a consumer study. The fonnula with 100percnt; isomalt was liked significantly more by consumers than the other formulas. [source]

PHYSICAL, SENSORY AND FLOW PROPERTIES OF WHEAT STARCH,DAIRY BY-PRODUCT SPRAY-DRIED PEKMEZ MIXTURES

JOURNAL OF TEXTURE STUDIES, Issue 2 2008
DURMU
ABSTRACT Pekmez, also known as a concentrated grape juice, was spray dried in a laboratory-type pilot drying unit to obtain pekmez powder (PP). The flow characteristics of PP, wheat starch (WS) and some dairy by-products (whey powder, skim milk powder, calcium caseinate and sodium caseinate) systems as binary and ternary mixtures were studied. The empirical power law model fitted the apparent viscosity,rotational speed data. PP,dairy by-product and WS,dairy by-product mixed solutions exhibited a shear-thinning behavior at 21C with flow behavior index (n) values of 0.86 , n , 0.92 and 0.06 , n , 0.27, respectively. WS,dairy by-product mixed solutions showed high shear-thinning behavior with the highest consistency index (k = 25,425,180,599 mPa·sn). However, PP,WS and PP,WS,dairy by-product mixed solutions at the same temperature exhibited the shear-thickening behavior with flow behavior index (n) values of 1.05 , n , 1.18. PRACTICAL APPLICATIONS Pekmez has become popular as a healthy food product; therefore, its rheologic properties were extensively studied by some researchers. However, pekmez powder (PP) is a new product and has not been produced yet in the food industry. Spray drying of foods has been spread recently in almost all food industry branches because it provides some advantages such as extending the shelf life, storage stability, decreasing the storage costs of the food products, etc. For this reason, production technology is first developed; PP is produced and studied in this study. There is no published data informing the rheologic, physical and sensory properties of pekmez or PP as binary and ternary mixtures with other components such as wheat starch (WS) and any dairy by-product. The purpose of this study was mainly to characterize the rheologic behavior of the PP,WS,dairy by-product mixed solutions and determine their physical and sensory properties. [source]

FUNCTIONALITY COMPARISON BETWEEN DERIVATIZED WHEY PROTEINS AND A PREGELATINIZED STARCH

JOURNAL OF TEXTURE STUDIES, Issue 4 2002
H. M. HUDSON
ABSTRACT A process has been patented to produce stabilizing ingredients from whey proteins which are applicable over a wide range of typical food conditions and do not require heat or the addition of salts to induce thickening functionality. Once reconstituted in deionized water, solutions were evaluated and compared with water holding performance and rheological attributes of a pregelatinized cornstarch. Rotational viscometry was performed at pH values between 3 and 8, temperatures between 5 and 90C, and shear rates between 1 and 100 s,1. Derivatized whey protein powders and pregelatinized starch displayed pseudo-plastic behavior under shear at all temperatures tested. During temperature ramps from 5 to 90C, derivatized whey protein flow properties were essentially unchanged by varying pH. However, viscosity after the temperature increase was higher than initial values, possibly due to additional protein denaturation and hydrophobic interactions. Derivatized powders were stable and retained desired functionality over a wide range of food processing and preparation conditions and may therefore possess applicability to many products currently utilizing modified starches or hydrocolloids to texturize. [source]

INFLUENCE OF AROMA COMPOUNDS ON LARGE DEFORMATION PROPERTIES OF STARCH-BASED SYSTEMS DURING AGING

JOURNAL OF TEXTURE STUDIES, Issue 3 2001
G. ARVISENET
The effect of aroma compounds on the texture of gelled aqueous corn starch systems was studied by uniaxial compression during aging for 18 days. Three different types of behavior were observed, depending on the nature of the added aroma compound. Isoamyl acetate did not modify the measured parameters, compared with nonflavored products. Linalool, known for its ability to form inclusion complexes with amylose, modified the parameters which are usually considered to be governed by the rearrangement of amylose chains. Ethyl hexanoate modified the parameters depending mostly on amylopectin. These results suggest that the nature of the aroma compound may play a major role in interactions with starch. These interactions can be different from inclusion complexes involving amylose chains only, the latter being widely described by different authors. [source]

A Short-Term Bioresorbable Bone Filling Material Based on Hydroxyapatite, Chitosan, and Oxidized Starch Tested in a Novel Orthotopic Metaphyseal Mouse Model,

ADVANCED ENGINEERING MATERIALS, Issue 8 2009
Elias Volkmer
Despite significant advances in orthopedic surgery, no perfect bioresorbable bone-filling material has yet been clinically established. A new candidate material based on hydroxyapatite, chitosan and oxidised starch, which has the potential to covalently bind to bone in a watery milieu was tested in a new murine model. A special focus lies on the in vivo biocompatibility and bioresorbability of the new material. [source]

From Starch to Metal/Carbon Hybrid Nanostructures: Hydrothermal Metal-Catalyzed Carbonization,

ADVANCED MATERIALS, Issue 18 2004
H. Yu
An efficient method has been successfully realized for the controlled synthesis of various metal/carbon nanoarchitectures. The formation of metal/carbon nanocables and nanochains via a facile and mild hydrothermal carbonization co-reduction process (HCCR) is reported. The method involves the use of starch and noble metal salts as starting materials under mild conditions (, 200,°C). [source]

Starch in Food: Structure, Function and Applications

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2006
Dr Narpinder Singh
No abstract is available for this article. [source]

Composition and functional properties of rice

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2002
Zhongkai Zhou
Summary Starch, protein and lipids are the main rice grain components that affect cooking and eating quality. An analysis of the literature indicates that rice of good eating quality shows the following characteristics: low amylose and low protein contents and large breakdown as measured by an amylograph. However, there are significant cultural differences in quality preferences and the most important acceptance factors for Asian consumers living in the United States are cooked rice appearance and aroma. This review examines the major constituents of rice (starch, lipid and protein) and their impact on eating quality as reflected by the functional properties of rice. [source]

Synthesis and properties of starch-graft-acrylic acid/Na-montmorillonite superabsorbent nanocomposite hydrogels

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008
Ebru Al
Abstract The graft copolymerization of acrylic acid (AA) onto starch was carried out with monomer/starch weight ratio = 1.5. Cerium ammonium nitrate (CAN) and N,N,-methylenebis acrylamide (NMBA) were used as initiator and crosslink agent, respectively. Na-montmorillonite was used as nanoparticles. Starch- graft -acrylic acid/Na-MMT (S -g-AA/MMT) nanocomposite hydrogels were characterized by X-ray diffraction (XRD) and FTIR analysis. The effect of Na-MMT content in nanocomposite hydrogels on the swelling behavior was investigated. Increasing the Na-MMT/monomers ratio up to 1% causes an increment in water absorbency, which indicates that Na-MMT can improve the ability of water absorbency but further increase of Na-MMT causes a decrease in water absorbency. In addition, we describe the removal of safranine T from aqueous solutions using S -g-AA/MMT nanocomposite hydrogels. Effects of various parameters such as treatment time, initial dye concentration, and amount of the Na-MMT were investigated. The Freundlich equations were used to fit the equilibrium isotherms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Starch and albumin mixture as replacement fluid in therapeutic plasma exchange is safe and effective

JOURNAL OF CLINICAL APHERESIS, Issue 5 2008
Gladys P. Agreda-Vásquez
Abstract Therapeutic plasma exchange (TPE) is an effective treatment in Myasthenia gravis (MG) and Guillain-Barré syndrome (GBS) and 5% human albumin is the replacement fluid of choice; however, it is expensive. More recently, it has been suggested that starch is a safe and cheaper choice to human albumin. Objective: To evaluate our 5-year experience using 3% hydroxyethyl starch (HES) and 5% human albumin mixture, as replacement fluid in TPE for these diseases. Materials and methods: Retrospective study carried out from January 2001 through September 2006. We included those patients with MG and GBS undergoing TPE. We analyzed clinical outcome (CO) and adverse events (AE) and our results were compared with a previous study which included similar patients undergoing TPE using just 5% human albumin. Results: Thirty-one procedures were carried out in 26 patients, a total of 147 TPE sessions. In the group of MG we had 57% complete responses (CR) and 86% overall response (OR) while in the group of GBS we had 40% CR and 60% OR. When we analyzed our CO with the previous study no statistical differences were found. Mean processed plasma volume (PPV) was 4.2 in MG and 5.5 in GBS. Twenty patients had AE, being hypotension and catheter dysfunction the most frequent ones, while tachycardia, hypertension and paresthesias were statistically more frequent in the HES/albumin group. Conclusions: TPE with a mixture of 3% HES and 5% human albumin is as effective and safe as 5% human albumin alone for patients with these diseases. J. Clin. Apheresis, 2008. © 2008 Wiley-Liss, Inc. [source]

RHEOLOGICAL PROPERTIES OF CHEMICALLY MODIFIED RICE STARCH MODEL SOLUTIONS

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2006
C.S. RAINA
ABSTRACT Native rice starches have poor resistance to shear, and fair stability to retrogradation with soft texture, which can be altered through chemical modifications. Starch from broken pieces of rice of three rice cultivars (PUSA-44, PR-106 and PR-114) was chemically modified by etherification and esterification reactions by different combinations of modification reagents to investigate the effect of modification on the rheological properties of rice starches. The modification resulted in shear stable gel with apparent pseudoplastic characteristics. The viscosity of starches increased upon acetylation and dual modification as a result of increase in solubility. However, cross-linking had shown the reverse effect. The flow behavior index (n) and consistency coefficient (k) were significantly (P , 0.05) improved upon modification in acetylated and dual-modified starches. The effect of modification on the rheological properties was observed in similar pattern in all the three rice cultivars but varied significantly in variety PUSA-44 may be because of its relatively higher amylose content. [source]

PROPERTIES of CROSS-LINKED STARCH PRODUCED IN A SINGLE SCREW EXTRUDER WITH and WITHOUT A MIXING ELEMENT

Evaluation of Nondigested Carbohydrates in Hydroxypropylated Tapioca Starch

JOURNAL OF FOOD SCIENCE, Issue 1 2010
M. Tachibe
ABSTRACT:,In vitro,and,in vivo,digestibilities of hydroxypropyl starch were investigated to determine an appropriate nondigested carbohydrate assaying method for hydroxypropyl starch. Hydroxypropyl tapioca starch (HPTS), with a 0.338 degree of substitution, was used as a hydroxypropyl starch source. Practically all nondigested carbohydrate in HPTS was low molecular weight and was not precipitated in 78% ethanol. The contents of nondigested carbohydrate in HPTS and in effluents of ileorectomized rats fed the HPTS diet obtained by the AOAC 2001.03 (enzyme-gravimetric-HPLC method) were almost the same, 56% and 59%, respectively. The recovery of hydroxypropyl groups from ileorectomy effluents was 98%. The AOAC 2001.03 method is suggested to be appropriate in determining the content of nondigested carbohydrates in hydroxypropyl starch. [source]

Production of Resistant Starch by Extrusion Cooking of Acid-Modified Normal-Maize Starch

JOURNAL OF FOOD SCIENCE, Issue 7 2009
Jovin Hasjim
ABSTRACT:, The objective of this study was to utilize extrusion cooking and hydrothermal treatment to produce resistant starch (RS) as an economical alternative to a batch-cooking process. A hydrothermal treatment (110 °C, 3 d) of batch-cooked and extruded starch samples facilitated propagation of heat-stable starch crystallites and increased the RS contents from 2.1% to 7.7% up to 17.4% determined using AOAC Method 991.43 for total dietary fiber. When starch samples were batch cooked and hydrothermally treated at a moisture content below 70%, acid-modified normal-maize starch (AMMS) produced a greater RS content than did native normal-maize starch (NMS). This was attributed to the partially hydrolyzed, smaller molecules in the AMMS, which had greater mobility and freedom than the larger molecules in the NMS. The RS contents of the batch-cooked and extruded AMMS products after the hydrothermal treatment were similar. A freezing treatment of the AMMS samples at ,20 °C prior to the hydrothermal treatment did not increase the RS content. The DSC thermograms and the X-ray diffractograms showed that retrograded amylose and crystalline starch,lipid complex, which had melting temperatures above 100 °C, accounted for the RS contents. [source]

Hydroxypropylated Tapioca Starch Retards the Development of Insulin Resistance in KKAy Mice, a Type 2 Diabetes Model, Fed a High-Fat Diet

JOURNAL OF FOOD SCIENCE, Issue 7 2009
Makoto Tachibe
ABSTRACT:, The hypoglycemic and antidiabetic effect of hydroxypropyl tapioca starch (HPTS, degree of substitution = 0.180) was investigated in male KKAy mice. Mice were fed a purified high-fat (20%) diet without or with HPTS (5% or 10%) for 33 d. Gelatinized tapioca starch (TS) was used as a reference. Fasting blood glucose concentrations, days 14 and 28, were significantly lower in the 10% HPTS group compared with the reference. In an oral glucose tolerance test (OGTT), day 28, blood glucose concentrations in the 5% HPTS group, at 60, 90, and 120 min, and in the 10% HPTS group, at 30, 60, and 90 min after oral administration of glucose, were significantly lower compared with the reference. The area under the glucose curve (AUC) for glucose in both HPTS groups was significantly lower compared with the reference. Energy intake was significantly lower in the 10% HPTS group compared with the reference. At the end of the experiment, adiponectin concentrations were significantly higher in the 10% HPTS group compared with the reference. A homeostasis model assessment of insulin resistance (HOMA-IR) tended to be lower in the 10% HPTS group compared with the reference, whereas a quantitative insulin sensitivity check index (QUICKI) was significantly higher in both HPTS groups compared with the reference. These results show that HPTS retards the development of insulin resistance in KKAy mice fed a high-fat diet. [source]

High-Hydroxypropylated Tapioca Starch Improves Insulin Resistance in Genetically Diabetic KKAy Mice

JOURNAL OF FOOD SCIENCE, Issue 3 2009
R. Kato
ABSTRACT:, The hypoglycemic and antidiabetic effect of hydroxypropyl tapioca starch (HPTS) with a varying degree of substitution (DS: 0.058, 0.091, and 0.180) was investigated in rats and KKAy mice, an animal model of type 2 diabetes. The positive incremental area under the curve (IAUC) for glucose significantly decreased as the DS of HPTS increased. The IAUC after intragastric intubation of the highest HPTS (HPTS-III, DS = 0.180) was 55% of the IAUC of tapioca starch (TS). After 28 d, fasting blood glucose and insulin concentrations were significantly lower in rats fed HPTS-III (50 g/kg diet) than in those fed TS (P < 0.05). In KKAy mice fed HPTS-III (50 or 100 g/kg diet) for 33 d, as compared with TS, there was a delay in the detection of glucose in urine and also a decreased incidence of finding glucose in urine on days 7, 21, and 28; in addition, the AUCs for glucose in the oral glucose tolerance test on days 14 and 28 were significantly lower (P < 0.05 and P < 0.05, respectively). The plasma adiponectin concentration and the quantitative insulin sensitivity check index (QUICKI) were significantly higher in mice fed HPTS-III than in those fed TS (P < 0.01), whereas the homeostasis model assessment of insulin resistance (HOMA-IR) was lower (P < 0.01). Energy intake was significantly lower in mice fed HPTS-III than in those fed TS. These findings show that HPTS with a high DS resists digestion by ,-amylase and improves insulin resistance in KKAy mice by decreasing energy intake. However, the potential mechanism by which HPTS-III decreases energy intake is unclear at present. [source]

Contribution of the Starch, Protein, and Lipid Fractions to the Physical, Thermal, and Structural Properties of Amaranth (Amaranthus caudatus) Flour Films

JOURNAL OF FOOD SCIENCE, Issue 5 2007
D. Tapia-Blácido
ABSTRACT:, Amaranth protein,lipid (PL) and protein (P) films were elaborated and compared with amaranth flour films in order to determine the contribution of the interactions between the biopolymer (starch and protein) and the lipids to the film properties. The films were made by the casting method, using the same glycerol concentration (0.9 g glycerol/100 g solution). A separation of the lipid fraction in the PL films and a polymorphic transformation of the corresponding fatty acids were observed by differential scanning calorimetry (DSC) and verified by an analysis of the microstructure by scanning electron microscopy (SEM). The flour films showed no separation of the lipid fraction, evidence that the lipids were strongly associated with the proteins and homogenously distributed throughout the starch network, contributing to the good mechanical properties when compared to the PL films and to the excellent barrier properties when compared to both the PL and P films. The protein-protein interactions also contributed to the mechanical properties of the flour films. The presence of proteins and lipids in the flour films had an important effect on film solubility, and also on the color and opacity of the films. This study showed that the flour film properties depended on the interactions formed by their polymers (starches and proteins) and by the lipid, on the distribution of these interactions within the film matrix and on the concentrations of each component in the film. [source]

Characterization of Honey Amylase

JOURNAL OF FOOD SCIENCE, Issue 1 2007
Sibel Babacan
ABSTRACT:, The major ,-amylase in honey was characterized. The optimum pH range and temperature were determined for the enzyme as 4.6 to 5.3 and 55 °C, respectively. The enzyme was stable at pH values from 7 to 8. The half-lives of the purified enzyme at different temperatures were determined. The activation energy for heat inactivation of honey amylase was 114.6 kJ/mol. The enzyme exhibited Michaelis,Menten kinetics with soluble starch and gave KM and Vmax values of 0.72 mg/mL and 0.018 units/mL, respectively. The enzyme was inhibited by CuCl (34.3%), MgCl2 (22.4%), and HgCl2 (13.4%), while CaCl2, MnCl2, and ZnSO4 did not have any effect. Starch had a protective effect on thermal stability of honey amylase. Therefore, it might be critical to process or control the amylase in honey before incorporation into starch-containing foods to aid in the preservation of starch functionality. One step could involve heat treating honey with other ingredients, especially those that dilute and acidify the honey environment. [source]

Effect of Heat-Moisture Treatment and Acid Modification on Rheological, Textural, and Differential Scanning Calorimetry Characteristics of Sweetpotato Starch

JOURNAL OF FOOD SCIENCE, Issue 6 2005
Sukhcharn Singh
ABSTRACT Sweetpotato starches were characterized to understand the changes upon modification by acid and heat-moisture treatment (HMT) in the rheological, differential scanning calorimetry (DSC), and textural characteristics of starch isolated from the sweetpotato variety PSP-21 and to compare these findings with those of commercially available arrowroot starch. The native sweetpotato starch had a Type A pasting profile characterized by a high peak viscosity (PV) (741.5 rapid viscoanalyzer unit [rvu]), with a high breakdown (378.8 rvu) and low cold paste viscosity (CPV) (417.6 rvu). After HMT, there was a marked decrease in the PV (639.1), a very slight breakdown (113.5 rvu) and an increase in CPV (759.5 rvu), more like a Type C pasting profile. However, acid modification did not notably change the pasting profile of native sweetpotato starch. The DSC characteristics were also affected significantly after modifications. The gelatinization temperature parameter to onset (To) decreased significantly after HMT and acid modification. The gelatinization enthalpy decreased during HMT from 15.98 to 14.42 J/g. The gel strength of acid-modified starch was the highest compared with that of HMT and native sweetpotato and arrowroot starches. [source]

Phase Behavior of a Meat-Starch Extrudate Illustrated on a State Diagram

JOURNAL OF FOOD SCIENCE, Issue 8 2002
C.I. Moraru
ABSTRACT: The phase behavior of a meat-starch extruded system was illustrated on a state diagram. A mixture of meat and potato granules (1.48:1) was extruded with a twin-screw extruder. The extrudates were equilibrated at relative humidities between 0 to 88% and their glass transitions were determined. Starch and proteins were phase separated at macromolecular level and retained their own phase transitions. The state diagram of the system showed that proteins dictated the texture of the mixed system, with starch contributing to the high value of the mechanical properties. Water had a plasticizing effect on both biopolymers. At room temperature, the extrudates with aw < 0.32 were glassy, while those with aw > 0.57 were rubbery. [source]

Effect of Moisture Content on the Thermomechanical Behavior of Concentrated Waxy Cornstarch,Water Preparations, A Comparison with Wheat Starch

JOURNAL OF FOOD SCIENCE, Issue 3 2002
A. Rolée
ABSTRACT: The rheological behavior of waxy cornstarch preparations at intermediate moisture contents (30 to 60% w/w) was studied by dynamic mechanical thermal analysis (DMTA). Differential scanning calorimetry (DSC) and electron spin resonance (ESR) experiments were also performed in parallel. The results were compared to those obtained previously for wheat starch. DMTA results evidenced a critical moisture content (between 50 and 55%) for waxy cornstarch that delimited a radical change in the rheological behavior both at room temperature and during heating. This critical water content was around 45% for wheat starch. [source]

Properties of Arrowroot Starch Treated with Aqueous HCl at Ambient Temperature

JOURNAL OF FOOD SCIENCE, Issue 1 2002
J.K. John
Arrowroot starch was acid-treated using 2.2 M HCl at 29 to 30° C for durations of 0 to 72 h, and properties of the control and modified samples were compared. Increasing length of acid treatment produced a progressive decline in amylose blue value, intrinsic viscosity, and swelling power, as well as an increase in free sugars and solubility. Differential scanning calorimetry (DSC) studies highlighted changes effected by acid-treatment in the gelatinization behavior of the starch samples. Gel permeation chromatography (GPC) studies on 32- and 72-h acid-treated samples indicated a greater proportion of dextrins with a higher percentage of reducing sugars, compared to the control. While X-ray diffraction data suggested minor changes in the crystal phase impacted by acid-treatment, in vitro digestibility of both control and acid-treated samples did not show any appreciable change in overall patterns. [source]

Mechanical Properties, Water Vapor Permeabilities and Solubilities of Highly Carboxymethylated Starch-Based Edible Films

JOURNAL OF FOOD SCIENCE, Issue 1 2002
K.W. Kim
ABSTRACT: Tensile strength (TS), elongation (E), water vapor permeabilities (WVP) and solubilities were determined for highly carboxymethylated starch (HCMS)-based edible films plasticized with sorbitol (S), xylitol (X), mannitol (M) and glycerol (G). TS and E of HCMS-based film increased as the concentration of plasticizer S, M or × increased. TS of the HCMS-based film containing combined plasticizers were higher than those of films containing single plasticizer. The WVP of HCMS-based films seemed to decreased as the concentration of M, X or G plasticizer increased. Increasing plasticizer concentrations in HCMS-based film resulted in decreasing solubility of the films. [source]

Bihon-Type Noodles from Heat-Moisture-Treated Sweet Potato Starch

JOURNAL OF FOOD SCIENCE, Issue 4 2001
L.S. Collado
ABSTRACT Sweet potato starch (SPS) has limited uses in the Philippines, but modification of its properties may make it more suitable for use in traditional products that normally use other types of starch. Heat-moisture treatment was applied to native SPS (HMTSPS), which was used as a substrate and composite with maize starch (MS) to produce bihon -type starch noodles. Preliminary quality scoring showed that acceptability scores of raw starch noodles, plain boiled, and sautéed noodles made from 100% HMTSPS and 50% HMTSPS:50% MS were not significantly different from the commercial bihon. However, consumer testing is recommended to further validate acceptability of the sweet potato for bihon. [source]

Lipid Addition to Improve Barrier Properties of Edible Starch-based Films and Coatings

JOURNAL OF FOOD SCIENCE, Issue 6 2000
M.A. García
ABSTRACT: Effects of formulation (lipid presence, type of starch, and plasticizer) on microstructure, water vapor (WVP) and gas (GP) permeabilities of films and coatings were analyzed. Plasticizer was necessary to maintain film and coating integrity and to avoid pores and cracks. Films made from high amylose starch showed lower WVP and GP than regular corn starch films; permeabilities of films with sorbitol (20 g/L) were lower than those with glycerol. The addition of 2g/L sunflower oil to the formulations decreased WVP of starch-based films; X-ray diffraction and Differential Scanning Calorimetry experiments demonstrated that films with plasticizer and lipid showed lower crystalline-amorphous ratio compared to films without additives. Microstructural observations helped explain the decrease of the film permeabilities during storage. [source]

Immediate drug release from solid oral dosage forms

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2005
Thomas Schreiner
Abstract Fast drug release from solid dosage forms requires a very fast contact of the vast majority of the drug particles with the solvent; this, however, is particularly delayed in tablets and granulations. Starch and cellulose substances favor the matrix disintegration during the starting phase and the generation of the effective dissolution surface of the drug substance, thereby. To investigate the very complex interrelation between the functionality of commonly used excipients and the structural effects of the production processes, wettability, porosity, water uptake, and drug release rates of several ketoprofen-excipient preparations (powder blends, granulations, tablets) were measured. Significant linear correlation between these parameters, however, was not achieved; only qualitative tendencies of the effects could be detected. In consequence, a general mathematical model describing the mechanistic steps of drug dissolution from solid dosage forms in a fully correct way was not realized. However, the time-dependent change of the effective dissolution surface follows stochastic models: a new dissolution equation is based on the differential Noyes-Whitney equation combined with a distribution function, e.g. the lognormal distribution, and numerically solved with the software system EASY-FIT by fitting to the observations. This new model coincides with the data to a considerably higher degree of accuracy than the Weibull function alone, particularly during the starting, matrix disintegration, and end phases. In combination with a procedure continuously quantifying the dissolved drug, this mathematical model is suitable for the characterization and optimization of immediate drug release by the choice and modification of excipients and unit operations. The interdependence of some characteristic effects of excipients and production methods is discussed. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:120,133, 2005 [source]