bluuebunny/crossref_metadata_2025 huggingface dataset:
ADAPTATIONS TO AN HIV COUNSELING AND TESTING INTERVENTION FROM A COUNSELOR PERSPECTIVE
Authors: Mckay Virginia R. , Dolcini M. Margaret , Conte Kathleen P. , Catania Joseph A.
Published: October 2014

Understanding the balance between fidelity and adaptation for evidence‐based interventions has the potential to improve their translation from research to practice. The Translation into Practice study explores variation in program implementation within organizations utilizing the RESPECT program, an HIV counseling and testing intervention. Counselors (N = 70) were interviewed using a semistructured interview guide to examine both the influential factors on, and the subsequent adaptations to, RESPECT. Almost all counselors reported making adaptations (N = 69). Adaptations were made both to key characteristics (mean [M] = 2.24, standard deviation [SD] = 1.3) and to core components (M = 0.5, SD = 0.8). Counselors identified the environmental context and factors within the counseling context as common influences leading to adaptation. These findings suggest adaptations were a routine part of program usage. To improve implementation of the RESPECT program, further research is needed to assess the degree to which adaptations can be made to better meet the needs of agencies and clients without compromising fidelity.
HOW STABLE IS STABLE? DEFINING AND MEASURING HOUSING STABILITY
Authors: Frederick Tyler J. , Chwalek Michal , Hughes Jean , Karabanow Jeff , Kidd Sean
Published: October 2014

Despite housing stability being a key concept in housing and homelessness policy, research, and service provision, it remains poorly defined and conceptualized, and to date there are no standard measures. We use in‐depth qualitative interviews with 51 young people transitioning away homelessness over the course of a year to examine the core dimensions of housing stability. Due to the potential for sudden change, we define housing stability as the extent to which an individual's customary access to housing of reasonable quality is secure. We define housing security among 8 main dimensions: housing type, recent housing history, current housing tenure, financial status, standing in the legal system, education and employment status, harmful substance use, and subjective assessments of housing satisfaction and stability. Based on these dimensions, we suggest a brief 13‐question scale that measures housing security.
MEANINGS OF COMMUNITY IN CONTEXTS OF MULTICULTURE: THE ROLE OF CITIZENSHIP, IDENTITY, AND CULTURAL CHANGES
Authors: Barbieri Irene , Zani Bruna , Sonn Christopher
Published: October 2014

Sense of community (SOC) can be an important concept in relation to cultural and social changes affecting Western societies because of immigration. The focus of this article is on community, immigration, and contexts of multiculture as the starting point to analyze changes and their consequences in everyday lives. Interviews were conducted with 15 leaders living in Reggio Emilia's Station Zone (Italy) to explore meanings of SOC in the contexts of multiculture. The interviews were analyzed for recurring and unique themes. Results show the importance of immigrants’ culture of origin, which affects their idea of community, as well as feelings about identity and citizenship, perceptions of the context, and intercultural relation. Different results were found for participants who are native to Italy. We discuss the results with reference to SOC and immigration in a global world.
Microbiological changes, shelf life and identification of initial and spoilage microbiota of sea bream fillets stored under various conditions using 16S rRNA gene analysis
Authors: Parlapani Foteini F , Kormas Konstantinos Ar , Boziaris Ioannis S
Published: October 2014

BACKGROUND

Sea bream fillets are one of the most important value‐added products of the seafood market. Fresh seafood spoils mainly owing to bacterial action. In this study an exploration of initial and spoilage microbiota of sea bream fillets stored under air and commercial modified atmosphere packaging (MAP) at 0 and 5 °C was conducted by 16S rRNA gene sequence analysis of isolates grown on plates. Sensory evaluation and enumeration of total viable counts and spoilage microorganisms were also conducted to determine shelf life and bacterial growth respectively.

RESULTS

Different temperatures and atmospheres affected growth and synthesis of spoilage microbiota as well as shelf life. Shelf life under air at 0 and 5 °C was 14 and 5 days respectively, while under MAP it was 20 and 8 days respectively. Initial microbiota were dominated by Pseudomonas fluorescens, Psychrobacter and Macrococcus caseolyticus. Different temperatures and atmospheres affected the synthesis of spoilage microbiota. At the end of shelf life, different phylotypes of Pseudomonas closely related to Pseudomonas fragi were found to dominate in most cases, while Pseudomonas veronii dominated in fillets under MAP at 0 °C. Furthermore, in fillets under MAP at 5 °C, new dominant species such as Carnobacterium maltaromaticum, Carnobacterium divergens and Vagococcus fluvialis were revealed.

CONCLUSION

Different temperature and atmospheric conditions affected bacterial growth, shelf life and the synthesis of spoilage microbiota. Molecular identification revealed species and strains of microorganisms that have not been reported before for sea bream fillets stored under various conditions, thus providing valuable information regarding microbiological spoilage. © 2014 Society of Chemical Industry
Managerial Efficiency in Higher Education Using Individual Versus Aggregate Level Data. Does the choice of Decision Making Units Count?
Authors: Barra Cristian , Zotti Roberto
Published: October 2014

This paper explores the use of a data envelopment analysis approach to decompose student's under‐attainment in a part attributable to the Faculties they are enrolled in and a part attributable to the students themselves. The mean measure of each Faculty's teaching efficiency is calculated using both individual and aggregate data. The results show that efficiency measures at aggregate level reflect both the student's effort and the characteristics of the institution to which they belong, suggesting that they might lead to ambiguous results. The estimates also reveal that Faculties need to stimulate their student's effort in order to perform better. Copyright © 2014 John Wiley & Sons, Ltd.
Red meat intake, insulin resistance, and markers of endothelial function among Iranian women
Authors: Barak Farzaneh , Falahi Ebrahim , Keshteli Ammar Hassanzadeh , Yazdannik Ahmadreza , Saneei Parvane , Esmaillzadeh Ahmad
Published: October 2014

Scope

Few data, with conflicting findings, are available linking red meat consumption to indicators of insulin resistance and endothelial dysfunction. This study aimed to investigate the association of red meat consumption with insulin resistance and endothelial dysfunction among a sample of female nurses in Isfahan, Iran.

Methods and results

This cross‐sectional study was carried out among 420 female nurses who were selected by a multistage cluster random sampling method. Usual dietary intakes were assessed using a validated food frequency questionnaire. Red meat intake was calculated by summing up the consumption of all kinds of red meat in foods and processed meat in sausages and fast foods. To measure serum concentrations of adhesion molecules and glycemic indexes, a fasting blood sample was taken. After adjustment for potential confounders, high red meat intake was significantly associated with higher fasting plasma glucose, homeostasis model assessment of insulin resistance, and lower quantitative insulin sensitivity check index. Although high red meat intake was significantly associated with higher serum insulin levels and lower homeostasis model assessment of beta‐cell function in the crude model, after controlling for BMI, the association was no longer significant. Red meat consumption was associated with high concentrations of E‐selectin, soluble vascular cell adhesion molecule‐1 (sVCAM‐1), and soluble intercellular adhesion molecule‐1 (sICAM‐1) after adjustment for different potential confounders.

Conclusion

We found that increased red meat intake was associated with high concentrations of plasma endothelial dysfunction biomarkers and abnormal glucose homeostasis among Iranian women. Prospective studies are required to confirm these findings.
Abnormal brain anatomical topological organization of the cognitive‐emotional and the frontoparietal circuitry in major depressive disorder
Authors: Qin Jiaolong , Wei Maobin , Liu Haiyan , Yan Rui , Luo Guoping , Yao Zhijian , Lu Qing
Published: October 2014

Purpose

Despite the increasing understanding of major depressive disorder (MDD) using neuroimaging techniques, the topological organization of anatomical networks underlying MDD remains unclear.

Methods

The topological organization of brain anatomical networks was explored using complex network approaches. Diffusion tensor image data of 29 MDD patients and 30 healthy controls were collected. Network metrics such as strength, efficiency, and centrality were computed after the construction of brain anatomical networks. Between‐group differences and correlations with clinical measurements were further explored.

Results

Compared with the healthy controls, MDD patients exhibited widely damaged information interactions in both cognitive‐emotional circuitry and frontoparietal circuitry. Moreover, the centralities in the right prefrontal cortex involving the right middle frontal gyrus and the right gyrus rectus were negatively correlated with the duration of disease. Additionally, the centrality in the right inferior frontal gyrus (triangular part) and the efficiency in the right superior frontal gyrus (orbital part) were both positively related to the depression severity.

Conclusion

These findings suggest that altered connectivity involved in affective and cognitive processing procedures might contribute to the pathogenesis of MDD. Magn Reson Med 72:1397–1407, 2014. © 2013 Wiley Periodicals, Inc.
Optimal partitions for first eigenvalues of the Laplace operator
Authors: Bozorgnia Farid
Published: October 2014

Given a bounded open set , we present numerical approximations for two problems related to minimal partitioning of the first eigenvalues of the Dirichlet Laplacian. The first problem is about minimizing the sum of first eigenvalues of the Dirichlet Laplacian. This partitioning problem arises as a steady state of a reaction‐diffusion process.

To do this, a new idea to approximate the second eigenfunction and second eigenvalue is presented. We use the qualitative properties of the minimization problem to construct a numerical algorithm to approximate optimal configurations. A rigorous analysis to show the convergence and the rate of convergence is given. Moreover, we discuss the numerical implementation of the resulting approach and present computational tests confirming the expected asymptotic behavior of optimal partitions with large numbers of partitions. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 923–949, 2015
The molecular pathology of noroviruses
Authors: Karst Stephanie M , Zhu Shu , Goodfellow Ian G
Published: October 2014

Norovirus infection in humans typically results in acute gastroenteritis but may also occur in many animal species. Noroviruses are recognized as one of the most common causes of acute gastroenteritis in the world, being responsible for almost 20% of all cases. Despite their prevalence and impact, our knowledge of the norovirus life cycle and the pathological processes associated with norovirus‐induced disease is limited. Whilst infection of the intestine is the norm, extraintestinal spread and associated pathologies have also been described. In addition, long‐term chronic infections are now recognized as a significant cause of morbidity and mortality in the immunocompromised. This review aims to summarize the current state of knowledge with respect to norovirus pathology and the underlying mechanisms that have been characterized to date. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
An effective ECC‐based user access control scheme with attribute‐based encryption for wireless sensor networks
Authors: Chatterjee Santanu , Das Ashok Kumar
Published: October 2014

For critical applications, real‐time data access is essential from the nodes inside a wireless sensor network (WSN). Only the authorized users with unique access privilege should access the specific, but not all, sensing information gathered by the cluster heads in a hierarchical WSNs. Access rights for the correct information and resources for different services from the cluster heads to the genuine users can be provided with the help of efficient user access control mechanisms. In this paper, we propose a new user access control scheme with attribute‐based encryption using elliptic curve cryptography in hierarchical WSNs. In attribute‐based encryption, the ciphertexts are labeled with sets of attributes and secret keys of the users that are associated with their own access structures. The authorized users with the relevant set of attributes can able to decrypt the encrypted message coming from the cluster heads. Our scheme provides high security. Moreover, our scheme is efficient as compared with those for other existing user access control schemes. Through both the formal and informal security analysis, we show that our scheme has the ability to tolerate different known attacks required for a user access control designed for WSNs. Furthermore, we simulate our scheme for the formal security verification using the widely‐accepted automated validation of Internet security protocols and applications tool. The simulation results demonstrate that our scheme is secure. Copyright © 2014 John Wiley & Sons, Ltd.
Enhancing the performance and security against media‐access‐control table overflow vulnerability attacks
Authors: Tzang Yih‐Jou , Chang Hong‐Yi , Tzang Chih‐Hsuan
Published: October 2014

A media‐access‐control (MAC) table of switches is used to store the MAC addresses of stations in a local area network (LAN) segment to enable frame forwarding. Each incoming frame is broadcast to all switch ports through a switch backplane when an MAC address is not registered in the MAC table. If an address is registered, the switch forwards the frame to the port connected to the destination host. An MAC table overflow (MTO) vulnerability attack causes the MAC table of all switches to overflow in an LAN segment, and all incoming frames are broadcast to every port in the switch. The attack degrades switch‐based LANs (each port of a switch comprises an individual operating domain and switch bandwidth) to bus‐based LANs (all ports are bounded to one operating domain and share a bandwidth similarly to a hub), causing information leakages and reducing the effective bandwidth; a virtual LAN configuration can reduce but not eliminate the associated damage. This paper presents the security effect of an MTO vulnerability attack, and a novel per‐port‐based MAC table design is proposed to solve this type of vulnerability. The experimental results indicate that the mechanism of the proposed design eliminates the damage caused by such attacks. Copyright © 2014 John Wiley & Sons, Ltd.
Application of response surface methodology (RSM) for optimization of cassava starch grafted polyDADMAC synthesis for cationic properties
Authors: Razali Mohd A. A. , Sanusi Nurhasikin , Ismail Hanafi , Othman Nadras , Ariffin Azlan
Published: October 2014

Response surface methodology was used to study the process optimization of cationic percentage through grafting diallyldimethylammonium chloride (DADMAC) into cassava starch. Based on Box–Behken design, quadratic models were developed to correlate the synthesis variables: concentration of DADMAC (A), concentration of initiator (B), and polymerization temperature (C), to the responses of cationic percentage (y). Analysis of variance (ANOVA) revealed that the concentration of initiator was the most significant variable for the response. The optimum preparation conditions for starch grafted polyDADMAC were 14% cationic using 31 g DADMAC/10 g dry starch of concentration DADMAC, a polymerization temperature of 74°C, and 4.92 g cerric ammonium nitrate/10 mL of initiator concentration.
Effect of different drying methods on the physicochemical and functional properties of Dioscorea opposita Thunb. starch
Authors: Zhang Zhidan , Gao Wenyuan , Li Xia , Jiang Qianqian , Xia Yuzhuo , Wang Haiyang , Huang Luqi , Guo Lanping
Published: October 2014

The effect of sulfur fumigation and freeze–drying on the physicochemical and functional properties of Dioscorea opposita Thunb. starch was investigated. Freeze–drying markedly decreased the AM content of starch from 16.68 to 8.59%. Both sulfur fumigation and freeze–drying decreased the protein content but obviously increased the water absorption capacity and swelling power. Sulfur fumigation significantly increased the solubility of starch. Retrogradation tests showed that Chinese yam starch had a poor stability of retrogradation in water, salty, sugar, and acidic medium, but a good stability in alkaline medium. SEM analysis showed that different drying methods had minor effects on the morphological properties of D. opposita cv. Ma starch. Although the pattern of D. opposita cv. Ma starch was C‐type and was not affected by drying methods, sulfur‐fumigation, and freeze–drying increased the crystalline degree of starches from 23.24 to 25.16% and 34.40%, respectively. A minor difference was found in the Fourier transform infrared spectra of native and treatment starches. After sulfur fumigation and freeze–drying, the peak gelatinization temperatures increased from 71.03 to 76.03°C and 83.07°C, respectively, whereas the gelatinization enthalpy and gelatinization range decreased.
Characterization of an acidophilic and thermostable α‐amylase from Alicyclobacillus sendaiensis NUST
Authors: Li Dali , Sheng Jiayuan , Yang Junfang , Yang Chengli , Zeng Zhen , Sheng Linli
Published: October 2014

This paper describes the characterization of an acidophilic and thermostable α‐amylase from Alicyclobacillus sendaiensis NUST. The MW of this enzyme was estimated to be 56 kDa by SDS–PAGE. The enzyme was stable over a range of pH from 2.5 to 5.5 with an optimum around 3.5. Maximum activity of the α‐amylase was observed at pH 3.5 and 85°C in the presence of soluble starch as substrate. The enzyme activity was decreased by Mg2+, Cu2+, Zn2+, Al3+, K+, Li+, Ag+, urea, EDTA, trichloroacetic acid and Tween 60 and inhibited by Hg2+, Ce2+ and SDS, whereas the activity was increased by Mn2+, DTT, and β‐mercaptoethanol. Ca2+and Fe2+ did not affect the enzyme activity.
Environmental friendly polysaccharide modification – rheological properties of oxidized starches water systems
Authors: Ptaszek Anna , Lukasiewicz Marcin , Bednarz Szczepan
Published: October 2014

Detailed rheological studies were performed in order to characterize a new class of modified starches. The polysaccharide was oxidized in a paste using H2O2 coupled with sodium tungstate as a catalyst. Oxidation processes were carried out in microwave (µν) and conventional (Δ) conditions. Commercially oxidized starch (E1404) was used as a reference material. Further analysis covers the investigation on polysaccharides chains degradation as a key factor for rheological properties. Pasting properties of the new starches may have approximately 100 times lower viscosity. The viscosity of the paste does not depend on the heating method during the modification process (µν or Δ). According to that, it might be stated that pasting before modification is fundamental for the deep changes of rheological and osmotic properties detected for water solutions of oxidation products. The viscosity which increases with shear rate allows identifying all pastes as shear‐thickening systems. Additionally, microscopic analysis was performed (AFM) in order to link the mechanical properties and inner structure of pastes obtained from modified starches. Results obtained allow to conclude that the investigated protocols (oxidation in paste) guide to the new class of oxidized starches. The oxidation follows the strong degradation of the starch, which affects in mechanical properties. The obtained material cannot serve as a thickening agent in food technology, although its properties may lead to other application possibilities like ion exchange or chelating agent.
Oxidized banana starch–polyvinyl alcohol film: Partial characterization
Authors: Palma‐Rodríguez Heidi M. , Aguirre‐Álvarez Gabriel , Chavarría‐Hernández Norberto , Rodríguez‐Hernández Adriana I. , Bello‐Pérez Luis A. , Vargas‐Torres Apolonio
Published: October 2014

Composites of polyvinyl alcohol, native banana starch, oxidized banana starch using glycerol like plasticizer, were studied by mechanical tests (MT), scanning electronic microscopy (SEM), differential scanning calorimetry (DSC) and solubility in water. The oxidized banana starch showed higher level of carboxyl groups than of carbonyl groups. Composites of native banana starch/polyvinyl alcohol and oxidized banana starch/polyvinyl alcohol showed irregularities, indicating incomplete dispersion of the polymers. However, the film elaborated with the blend oxidized banana starch/polyvinyl alcohol showed the highest mechanical properties and the melting temperature of the first transition, as well as the lowest water vapor permeability, indicating higher interaction between both polymers. The composite oxidized banana starch/polyvinyl alcohol showed higher water solubility than the one of its counterpart with native banana starch at 25°C, and similar values were obtained for both films at 60°C. The oxidation of banana starch in order to elaborate a film blended with polyvinyl alcohol improved some mechanical and barrier properties, and this composite could be used for specific applications in the packing of food.
Effects of protein removal on the physicochemical properties of waxy maize flours
Authors: Lu Dalei , Lu Weiping
Published: October 2014

The effects of protein removal on the physicochemical properties of waxy maize flours were investigated. Protein removal caused significant reduction in the P and S contents of starches. Starch granules had a smoother surface and low protein content (<6 g/kg) compared with the flours. Both flours and starches had a typical A‐type X‐ray diffraction pattern, with a crystallinity range of 29.8–32.2% and 27.7–30.6%, respectively. Flours had higher swelling power and solubility, and lower light transmittance than starches. The gelatinization enthalpy and onset temperature of starches were higher compared with those of their counterpart flours. The retrogradation of flours was significantly greater compared with that of starches. Protein removal increased the peak viscosity, trough viscosity, final viscosity, and breakdown, whereas it decreased the setback and pasting temperature. Genotypic differences in those maize were related to the physicochemical characteristics of the flours and starches.
A facile approach for controlled synthesis of hydrophilic starch‐based nanoparticles from native sago starch
Authors: Tay Soon Hiang , Pang Suh Cem , Chin Suk Fun
Published: October 2014

A facile approach for the preparation of hydrophilic starch‐based spherical nanoparticles from native sago (Metroxylon sagu) starch using the drop‐wise solvent exchange method was reported. Starch‐maleate monoester (SM) was initially synthesized from native sago starch and maleic anhydride in an aqueous medium, and SM nanoparticles was subsequently precipitated in absolute ethanol under controlled conditions. The present study was focused mainly on modulating of the solvent and non‐solvent systems to prepare SM nanoparticles of different morphologies. The pH of the solvent system and the nature of surfactants being added into the solvent system could influence the morphology of regenerated SM nanoparticles. SM nanoparticles of discrete and spherical shape were regenerated from a basic SM sample solution, or an acidic sample solution in the presence of an appropriate surfactant. SM nanoparticles with mean diameter of about 250 nm was obtained by precipitation in absolute ethanol in the presence of Brij 35 as the surfactant.
Selective degradation, oxidation, and characterization of hydroxyethyl starch for potential use as a drug carrier
Authors: Abbas Muhammad Azhar , Hameed Shahid , Kressler Joerg
Published: October 2014

The selective degradation, oxidation, and characterization of hydroxyethyl starch (HES) was successfully carried out. Different mass fractions of HES were obtained through degradation either using acidic (hydrochloric acid) or enzymatic (α‐amylase) hydrolysis under controlled pH, temperature, and concentration. The degraded samples were successfully oxidized using sodium hypochlorite solution to convert cyclic ether into carboxylic acid group. The degraded and oxidized samples were tested for their molar masses and structural properties using different techniques. The samples were further characterized using FTIR, and 1H NMR spectroscopy. The solubility check was also performed and a significant enhancement in water solubility of the degraded products of HES was observed which increased further on oxidation. This increased solubility may be utilized to enhance the water solubility of the drugs through coupling with degraded and oxidized HES.
Characterization of glucoamylase immobilized on magnetic nanoparticles
Authors: Panek Anna , Pietrow Olga , Synowiecki Józef
Published: October 2014

Magnetic support was prepared by precipitation from an alkaline solution of divalent and trivalent iron ions and subsequently was modified with 3‐aminopropyltriethoxysilane. FTIR analysis showed existence of a new Si–O–Fe bond in obtained particles. Scanning electronic microscopy images shows that the nanoparticles of all samples have particle size below 30 nm. Glucoamylase AMG 300L was immobilized onto the modified magnetic support using glutaraldehyde as a coupling agent. Obtained preparations had specific activity of 148 U/g of the support when measured at 55°C using maltose as substrate. The immobilized enzyme exhibited mass transfer limitation as reflected by a higher apparent Km value and a lower energy of activation. The immobilization was almost completely terminated after 30 min of the reaction at 30°C. The highest immobilization yield of the enzyme was achieved at glutaraldehyde concentration of 10 mM. The immobilization did not influence considerably on optimum pH and temperature of substrate hydrolysis catalyzed by investigated enzyme (55°C, pH 4.5). Moreover, immobilized glucoamylase was easily separated from the reaction medium by an external magnetic field and retained about 60% of initial activity after nine repeated cycles of enzyme reaction followed by magnetic separation.
Xylanase immobilization on functionalized polyaniline support by covalent attachment
Authors: Madakbaş Seyfullah , Danış Özkan , Demir Serap , Kahraman Memet Vezir
Published: October 2014

Chemically synthesized polyaniline (PANI) was used as polymeric support for xylanase immobilization. The polymer was first activated with glutaraldehyde and then xylanase was successfully immobilized. Xylanase bound polymer was characterized using FTIR. The optimum pH of the immobilized enzyme was at pH 5, which was shifted 1.0 pH unit to the acidic region when compared to the free enzyme. Thermal stability of the xylanase was improved with the immobilization. The characteristic properties of the immobilized and native enzyme, such as kinetic activity, reusability and storage stability were also studied at optimum pH and temperature. Immobilized enzyme exhibited better reusability and storage stability than the free one. Vmax values for the free and immobilized enzymes were calculated as 1.44 and 0.44 mg/mL/min, respectively. The Km values for the immobilized xylanase were found to be lower.
Rheological, thermal properties, and gelatinization kinetics of tapioca starch–trehalose blends studied by non‐isothermal DSC technology
Authors: Zhang Xiaoyu , Zhu Wenxue , Tong Qunyi , Ren Fei
Published: October 2014

In this paper, we studied the effects of trehalose on the rheological and thermal properties of tapioca starch (TS). Temperature sweep experiments showed that trehalose shifted the peak gelatinization temperature (TG′max) to higher value. Rheological features calculated from the power law model indicated that trehalose addition increased the consistency and decreased the thixotropy of TS gels. DSC experiments showed that trehalose retarded the gelatinization of TS–trehalose blends reflected in the increase of gelatinization temperature. The gelatinization kinetics was evaluated by a non‐isothermal technique based on the DSC endotherms. Kinetics analysis showed the addition of trehalose increased the activation energy and decreased the rate constants of TS–trehalose blends, indicating the same sugar effect as the rheological and DSC experiments. The work demonstrated that kinetics analysis could provide new evidences for the influence of trehalose on starch gelatinization.
Current advances of chemical and physical starch‐based hydrogels
Authors: Xiao Congming
Published: October 2014

Starch is a natural polymer, which has many unique properties. It has been utilized to prepare hydrogels and received growing attention. Starch‐based hydrogels (SH) are attractive and widely applied in a variety of fields such as biomedical, food packing, and others. In this article, the developments of physical and chemical SHs in the last decade are summarized. The common approaches to prepare hydrogels are briefly elucidated. Subsequently, the SHs obtained by chemical and physical cross‐linking methods are described. Then, the characteristics and potential applications of the SHs are introduced and correlated. Finally, suggestions about the future directions of developing SHs are presented.
Perspectives on the history of research on starch Part II: On the discovery of the constitution of diastase
Authors: Seetharaman Koushik , Bertoft Eric
Published: October 2014

Starch has been used over several millennia for a number of different applications. However, research on understanding this substance only spans about three centuries starting with Leeuwenhoek who observed it in 1716. This story of discovery of the molecular structure and architectural makeup of starch is chronicled in a series of six essays of which this is the second with a focus on diastase. Malted barley has been used in the brewing industry for millennia. However, it was not until 1833 that the active substance was identified and called diastase. Much of the research on diastase, interestingly, developed in the context of improving beer production efficiency and quality. Research in this area has given us the terms maltose, dextrin, and maltodextrin, which are still in use today. It was only in 1886 that the active substance was identified as a protein and soon thereafter as two distinct proteins. Finally, it was around mid 1900s that it was recognized that diastase contained several isoforms of the enzymes. This review on diastase spans over a period of 130 years.
Effect of amylopectin long chains on measured amylose content and their correlation with pasting properties
Authors: Park Inmyoung , Kim Seung‐Hyun , Chung Ill‐Min , Shoemaker Charles F.
Published: October 2014

This paper describes how long chains of AP affect the measurement of AM content and also investigates the rheological properties of purified starches from 14 rice cultivars. The AM content of each rice starch was determined by two different methods: the colorimetric iodine method and the Concanavalin A method. A high‐performance size exclusion chromatograph equipped with multi‐angle laser‐light scattering and RI detectors was used to determine the molecular weight of long chains of AP. Iodine blue values overestimated the AM content because iodine interacts with long chains of AP. However, long chains of AP with molecular weight under 0.89 × 104 g/mol (Calmochi101) did not affect the measurement of AM content by the iodine calorimetric method. Peak temperature correlated positively with AM content and negatively with the number of long chains of AP. Peak viscosity correlated negatively with AM content and molecular weight of long chains of AP. The difference between final viscosity and peak viscosity was larger in long, medium, and short grain rice varieties than in wx grain varieties.
The effect of xanthan on short and long‐term retrogradation of rice starch
Authors: Tang Minmin , Hong Yan , Gu Zhengbiao , Zhang Yayuan , Cai Xuran
Published: October 2014

The short‐term retrogradation of the rice starch (RS)/xanthan (Xan) mixtures was investigated by Brabender‐E viscograph and dynamic rheometer while the long‐term retrogradation was investigated by DSC and pulsed NMR (PNMR), respectively. RS and 0, 2.5, 5, and 10% Xan (based on RS weight) were prepared into RS/Xan mixtures at the ratios of 100:0, 40:1, 20:1, and 10:1 w/w, respectively. With increasing Xan concentration, the reduced setback (SB) value suggests the decrease of short‐term retrogradation. The gelation rate constant (k) of the mixtures increased during the storage at 4°C for 5 h due to phase separation. The endothermic enthalpy of the pastes of RS/Xan mixture after being stored at 4°C for 1, 3, 5, 7, 14, and 21 days were lower than the native starch stored for the same days. The spin–spin relaxation time (T2) indicating the water mobility of starch gels was detected. T2 decreased gradually with extending storage time, which may be attributed to the retrogradation of RS. T2 of the system with xanthan was apparently higher than that without. The overall results demonstrate the remarkable inhibitory effects of Xan on the retrogradation of RS.
Influence of storage temperature and autoclaving cycles on slowly digestible and resistant starch (RS) formation from partially debranched rice starch
Authors: Lee Kwang Yeon , Lee Suyong , Lee Hyeon Gyu
Published: October 2014

In this study, optimum conditions to produce slowly digestible starch (SDS) and RS from rice starch were investigated as a function of pullulanase concentrations, storage temperature, and autoclaving‐cooling cycles. Then, the physicochemical properties of the rice starches obtained were compared with native rice starch. Response surface methodology (RSM) was used to evaluate the effects of independent variables, namely the enzyme (pullulanase) concentration (X1), storage temperature (X2), and autoclaving‐cooling cycle (X3) on the production of SDS and RS fraction. The optimum conditions for SDS and RS occurred in the treatment with application of pullulanase at 482 and 610 µL, and storage temperature at 36 and 63°C with autoclaving cycles of three times, respectively. SDS and RS obtained through optimum conditions showed higher amylose content and water solubility index as compared to native starch. While the SF and water absorption index were lower than native starch. The extent of hydrolysis α‐amylose decreased in the order cooked starch>SDS>RS>native starch. SDS and RS had lower RVA parameters (except pasting temperatures) than native starch.
The effect of drying and whole grain content on the pasting, physicochemical and qualitative properties of pasta
Authors: West Ryan , Duizer Lisa , Seetharaman Koushik
Published: October 2014

Drying is one of the most important stages in pasta production because of its influence on texture and colour. Whole grain pasta has been associated with greater cooking loss and softer texture. The objective of this research was to examine the impact of the drying profile and whole grain content on pasting and physicochemical properties of starch in macaroni and see how the qualitative properties of macaroni are affected. A flour × drying interaction was detected in pasting properties of the samples with differences observed in peak viscosity, peak time and final viscosity in whole grains following drying. Hot stage microscopy showed restricted granule swelling following treatment, reducing amylose leaching, which partly governs viscosity. DSC showed a significant increase in ALC formation upon treatment, which can also reduce leaching. While the interaction between these main effects was significant for cooking loss, firmness and adhesiveness measured instrumentally, differences between drying conditions for either textural attribute could not be detected using a trained panel.
From native to multifunctional starch‐based excipients designed for direct compression formulation
Authors: Rashid Iyad , Al Omari Mahmoud M. H. , Badwan Adnan A.
Published: October 2014

The development of new materials, processes and in machinery plays an important role in pharmaceutical industry. This allows the solid dosage form manufacturers to improve and develop their processes toward the exploitation of direct compression and dry granulation (e.g., roll compaction) leading to relatively fast process and low cost. This review outlines a comprehensive understanding on the physico‐chemical and compaction properties of native and modified starches. The physical modification of native starch has been given a technical focus along with an understanding on the impact of their modified powder/tablet properties on direct compression attributes. All processes involved on starch modifications have been confined herein to the production of direct compression excipients with multifunctional purposes as most chemical modifications exhibit limited applications.
Effect of pH on the physicochemical and binder properties of tigernut starch
Authors: Builders Philip F. , Mbah Chukwuemeka C. , Adama Kenneth K. , Audu Momoh M.
Published: October 2014

Tigernut starch is starch extracted from the tubers of Cyperus esculentus L. a perennial herb commonly known as tigernut. The effect of pH on the foaming, gelatinization, solubility, swelling, paste clarity, viscosity, freeze–thaw stability, and binder efficiency of the starch in buffer solutions of pHs 4, 7, and 9.2, representative of acid, neutral, and alkaline pHs were evaluated. Marked pH responsiveness was observed in all these parameters to varying degrees. The foaming capacity, paste clarity, freeze–thaw stability, swelling, and viscosity increased while only the gelatinization temperature decreased with increasing pH. The pastes obtained at pHs 4 and 7 showed marked instability by forming a mass of hard coarse gel with the first freeze–thaw cycle while the paste of pH 9.2 maintained its normal viscoelastic‐gel texture even after the fourth freeze–thaw cycle. The properties of the ascorbic acid granules and tablets produced by wet granulation, using the pastes as binder showed pH‐responsiveness, with the granule formed with the paste of pH 9.2 showing higher mechanical strength and lower disintegration time. This study thus shows the diversity in the physicochemical and binder properties of tigernut starch with changes in pH.
Microwave mediated preparation of nanoparticles from wx corn starch employing nanoprecipitation
Authors: Juna Shazia , Hayden Stephan , Damm Markus , Kappe Christian O. , Huber Anton
Published: October 2014

The influence of alkali concentration, temperature, concentration of urea and KSCN on the shapes and sizes of wx corn starch precipitates (isolated via nanoprecipitation) were studied. A strong correlation was found between the molecular and hydrodynamic characteristics, determined by using asymmetrical flow‐field flow fractionation (AF4), and the resultant sizes of micro‐ and nanostructures of wx corn starch precipitates (SEM images). Treatment of wx corn in alkaline media at higher temperatures employing a dedicated microwave reactor resulted in the formation of submicron particles (SEM analysis). The apparent molecular characteristics of wx corn starch heated in 1 M NaOH at various temperatures employing a microwave reactor, decreased with increasing temperature and with a corresponding decrease in particle sizes (SEM images of the precipitates). An expansion and decrease in the overall densities of the starch structures was observed for wx corn in 1 M urea, 0.2 M NaOH at 130°C resulting in smaller particle sizes.
Influence of starch acetylation on selected rheological properties of pastes
Authors: Żmudziński Daniel , Ptaszek Anna , Grzesik Mirosław , Kruk Joanna , Kaczmarczyk Kacper , Liszka‐Skoczylas Marta
Published: October 2014

Selected rheological properties of acetylated starch pastes of different amylose content were discussed in the study. The rheological studies were carried out immediately after the preparation of the pastes as well as after 1 and 7 days of storage. For the paste of acetylated potato starch (P‐A), a phenomenon of oscillatory changes of viscosity with time was observed. The pastes of the acetylated amylostarch (AMY‐A) and acetylated waxy potato starch (AP‐A) exhibited the phenomenon of thixotropy. Based on the flow curves, the distribution of the time constants of the exponential rheological equation of state has been determined. They served to describe the contributions forming rheological properties. It has been noticed that during shear the phenomenon of the energy dissipation is predominant in AMY‐A (rheological characteristic time of 0.3 s) and AP‐A, whereas the elastic contributions are specific for the paste of acetylated potato starch (rheological characteristic time of 10−6 s). In order to describe the structural changes of AMY‐A and AP‐A pastes during flow, i.e. for the systems exhibiting frictional properties, the Cheng and Evans viscous structural theory has been applied. The rheological properties were then interpreted in light of the results of chromatographic and osmometric analyses.
Physicochemical properties of taro and maize starch and their effect on texture, colour and sensory quality of tomato ketchup
Authors: Sit Nandan , Misra Sudip , Baruah Devastuti , Badwaik Laxmikant S. , Deka Sankar C.
Published: October 2014

The physicochemical properties of starch from local cultivar of taro from North‐Eastern region of India, known as Panchamukhi (Colocasia esculenta var. antiquorum) were compared with maize starch. Both starches presented A‐type XRD pattern. The granule size of Panchamukhi taro starch was in the range of 2.19–4.28 µm, which was smaller, compared to maize starch granules (7.38–16.67 µm). Swelling and solubility of Panchamukhi taro starch were found to be higher compared to maize starch. The pasting profile of the starches showed that Panchamukhi starch had lower final viscosity (FV; 2940 cP) and setback viscosity (SV; 826 cP) compared to maize starch (FV of 3878 cP and SV of 1529 cP). The peak gelatinization temperature (Tp) of Panchamukhi taro starch was 74.36°C, which was significantly higher than Tp of maize starch (69.70°C). The incorporation of the starches during preparation of ketchup showed that both starches improved the texture. The colour of the ketchup was not affected by incorporation of starch up to 2% concentration. The sensory evaluation revealed that ketchup prepared using Panchamukhi taro starch was better than the control sample and was comparable to the ketchup prepared using maize starch.
Cross‐link copolymerization of cationic starch by gamma irradiation and its swelling‐shrinking and flocculating behaviors
Authors: Song Weiqiang , Guo Zhengchao , Yao Yiming , Zheng Hongjuan , Zhao Zhiwei
Published: October 2014

Cationic starch‐based hydrogels were synthesized by simultaneously irradiating starch, acrylamide (AM), dimethyldiallylammonium chloride (DMDAAC), and N,N′‐methylenebisacrylamide (MBA) in aqueous solution. A mechanism for hydrogel formation was proposed, and the product was characterized by NMR spectroscopy. Results showed that a minimum amount of AM and a maximum amount of DMDAAC were grafted onto the starch backbone at an absorbed dose of 4 kGy and a starch/AM/DMDAAC weight ratio of 6:9.8:4.2, while NDMDAAC/NAM reached its maximum value of 0.17. The equilibrium swelling ratio (Se) of the hydrogels progressively decreased with increased absorbed dose at a fixed starch/AM/DMDAAC/MBA ratio of 6:9.8:4.2:1.6, but the swelling rate parameter (τ) initially decreased up to 3 kGy and then increased. Meanwhile, the hydrogels showed similar shrinking behaviors with increased absorbed dose. At a fixed starch/AM/DMDAAC weight ratio of 6:9.8:4.2 and fixed gamma irradiation of 3 kGy, Se and τ decreased with increased MBA and solvent volume, but both water‐loss rate (Rloss) and minimum mass maintenance ratio (Rm0) progressively increased at 60°C. At a constant starch:AM:DMDAAC:MBA wt. ratio of 6:9.8:4.2:1.6, the flocculating activity of SADM decreased with absorbed dose increasing. The optimal flocculant concentration was 4 mg/L for SADMs synthesized at 1 and 2 kGy.
Enzymatic synthesis of epoxy fatty acid starch ester in ionic liquid–organic solvent mixture from vernonia oil
Authors: Desalegn Tegene , Garcia Ignacio J. Villar , Titman Jeremy , Licence Peter , Diaz Isabel , Chebude Yonas
Published: October 2014

In this study, epoxy fatty acid esters of cassava starch were synthesized by reacting cassava starch with vernonia oil methyl ester (epoxy ester) using 1‐butyl‐3‐methylimidazolium hexafluorophosphate, [C4C1Im][PF6] ionic liquid (IL) as a reaction medium and DMSO as co‐solvent. Lipase Candida antarctica fraction B (Novozyme 435) was used as a catalyst for the esterification reaction. In the optimized reaction conditions, a degree of substitution (DS) of 0.95 was achieved, at a reaction temperature of 40°C within 72 h of reaction time. The new cassava starch esters were characterized by infrared (FTIR), solid state NMR (CP/MAS 13C NMR), SEM, XRD, thermogravimetric analysis (TGA), and DSC. FTIR and NMR spectroscopy analyses confirmed the successful esterification of starch and the DS was calculated to be 0.95 by titration methods. SEM and XRD studies showed that the morphology and crystallinity of native cassava starch were significantly changed upon esterification producing a continuous and amorphous material. Finally, the thermal behavior of the native and the starch vernolate was investigated using TGA and DSC techniques. The results revealed a change in the characteristic melting point and decomposition pattern of the new polymer. The onset decomposition temperature of the new starch vernolate is similar to the native form.
Characterizing the chemical features of lipid and protein in sweet potato and maize starches
Authors: Xijun Lian , Haibo Sun , Lin Li , Hong Wu , Nan Zhang
Published: October 2014

The chemical features of lipid and protein in sweet potato and maize starches were investigated by comparing their IR and NMR spectra before and after hydrolysis by lipase or alkali protease. The results showed that the absence of C–H stretching vibration near 2930 cm−1 in IR spectra of sweet potato and maize starches hydrolyzed by lipase or protease was probably due to an interaction of amylose and amylopectin without lipid or protein. The results of 13C NMR showed that the lipid and protein were attached to each other in those two starches and both connected with maize starch, but only lipid connected directly with sweet potato starch. Lipid in starch probably inhibits crystal formation of starches, but protein in starch promotes the process. The characteristic fatty acids for sweet potato starch were CH3(CH2)13COOH + Lys + Glucose (G) and CH3(CHCH)4(CH2)4COOH + G, for maize starch, CH3(CHCH)6(CH2)29COOH. The typical peptides for sweet potato starch might be Lys + Phe + Ala + G + G and Leu + Lys + Leu + G, for maize starch, they were Asp + Val + Leu + Val and Asp + Glu + Leu + Glu.