Showing papers in "Starch-starke in 2014"

Recent trend in the physical and chemical modification of starches from different botanical sources: A review

Abstract: Starch is, after cellulose, the most abundant organic compound in nature. Modification of starch is carried out to enhance the positive attributes and to eliminate the shortcomings of the native starches. Various methods have been developed to produce a range of modified starches with a variety of characteristics and applications. Physically modified starches are simple and inexpensive because they can be produced without chemicals or even biological agents. In contrast, chemical modification is possible due to ubiquitous hydroxyl groups in starches that have been exploited for over a century, principally in the preparation of starch esters and ethers, but also in more subtle alterations, e.g., in order to tune the structure of starches for specific applications. All these techniques tend to alter the highly flexible starch polymer with changed physicochemical properties and modified structural attributes of high technological value for the food and non-food industries. Modification of starch is an ever evolving industry with numerous possibilities to generate novel starches which includes new functional and value added properties as demanded by the industry. This review aims to summarize the latest developments and recent knowledge regarding physically and chemically modified starches. This paper covers physical modification methods (pre-gelatinization, hydrothermal, and non-thermal processes), some chemical modifications and a combination of both.

How environmental stress affects starch composition and functionality in cereal endosperm

Abstract: Stressful environments can alter starch biosynthesis in cereal endosperm. The aim of this review is to carefully examine how starch functional properties are altered when plants encounter environmental parameters outside of the normal range. This is important because while growers and processors require grain yield stability and product uniformity this will be challenging in an era of variable weather patterns. Being able to predict the general physico-chemical nature of the starch as a result of growth status is a step towards the precise agriculture required for the 21st century. Variations in soil moisture and nutrient availability, ambient temperature, and atmospheric composition were all shown to affect starch functionality. Elevated temperature led to the most significant changes in both tropical and temperate cereals and amylose content was the most sensitive parameter under various environmental conditions. Genotypic variation appears to be a primary contributor for the response of cereal starches to environmental stress. Nonetheless, while a large amount of data from single controlled environmental stress experiment is currently available, comparably little is known about whether similar results would be achieved in multifactorial and large-scale settings. The challenges in terms of the need for more detailed experimental descriptions to lessen the study-to-study discrepancies of data and to enhance their interpretability were also discussed. © 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.

Resistant starch in food industry: A changing outlook for consumer and producer

Abstract: Due to the undeniable role of starch in nutrition, 60–70% of total energy consumed by most people around the world is provided by starch-based foods. Because of the low price and the availability of starch-based products, people accept these kinds of products more than ever. On the other hand, the selection of appropriate dietary fiber is vital due to the sensory characteristics' importance in functional foods, which play a key role in specifying consumers' acceptance. Resistant starch (RS) is a small fraction of starch which is resistant to digestion and may be fermented in the large intestine by microbiota. The unique characteristics of RS, such as its natural sources, gentle bland flavor, white color, low water holding capacity, etc. have made it a valuable supplement in the formulation of wide range of functional foods, even in microencapsulation of probiotics. While the aim of this study is to investigate the application of RS in food technology, it briefly reviews manufacturing, determining the amount of RS in the final product and prebiotic dosage needed to exert health benefits on the human gut as well.

Effects of grain milling on starch structures and flour/starch properties

Abstract: Milling or grinding of cereal grains to produce flour is frequently accompanied by damage to starch granules, disruption of starch crystalline structure, and degradation of starch molecules. Amylopectin (AP) molecules are more susceptible to degradation than amylose (AM) molecules as AM molecules, present in amorphous conformation in native starch granules, are more flexible than the rigid double helical crystallites made of AP branches. The changes of starch structures caused by milling alter starch properties, including gelatinization, pasting, swelling, solubility, and digestibility, and thus affect flour quality. The changes in starch structures and properties, however, are different between the grinding of cereal grains and that of isolated starch granules as the latter ignores the influences from non-starch components in grains. Hence, the grinding of isolated starch granules, commonly used to understand the effects of milling, does not represent the grinding of cereal grains. This review allows a better understanding in the changes of starch structures and properties by milling, which is important in the production of flour with desirable properties.

Shear degradation of molecular, crystalline, and granular structures of starch during extrusion

Abstract: This work describes the first investigation of starch degradation during extrusion occurring at multiple structural levels and explains the effects of the thermal and mechanical energy of extrusion. Investigated samples comprised starches with a range of amylose contents and of glycerol/water plasticizer contents. Structural analysis was performed using size-exclusion chromatography, XRD and light microscopy. The (branch) chain length distribution did not show apparent changes upon either thermal or mechanical energy treatment. Statistical analysis showed that mechanical energy played a dominant role in reducing starch molecular size and degree of starch crystallinity, while thermal energy only partially gelatinized starch granules with negligible effect on molecular size. The rigid crystallites of amylopectin in starch granules are more susceptible to shear degradation than the flexible amorphous amylose. Previous studies did not draw quantitative conclusions as to the relative importance of these two types of energy in extrusion on starch structural degradation. This mechanistic understanding from multi-level characterization is helpful to design the processing of starch-based biopolymers with improved functional properties.

Factors affecting starch utilization in large animal food production system: A review

Abstract: Dietary starch from feed grains represent the major energy-yielding sources in diets for large animals and starch effective digestion has a great impact on animal energy intake for meeting the substantial energy requirement to improve meat or milk productions. In general, site, extent and rateof starchdigestionareaffectedbyintrinsicandexternalfactorsthat canbeinterrelated andare thus not easily defined. As a consequence, research to obtain a deeper knowledge on how starch chemical and structural compositions may affect starch digestion potential of feed grains and therefore their nutritional value has progressed recently. The objectives of this review are: (1) to give an overview on inherent starch primary structures and interactions with other compounds within feed grains; (2) to discuss factors affecting starch digestion potential in feed grains; (3) to explore starch digestion mechanism, and linkages with animal performances, both for swine and ruminants. The criticism of methods commonly used to estimate starch digestibility from feed grains for swine and ruminants are also discussed.

Behaviour of starch exposed to microwave radiation treatment

Abstract: This work is an overview of the literature in the area of microwave treatment of starch strongly related to changes in its physicochemical, functional and structural properties. The importance of good knowledge of the microwave parameters and starch dielectric properties is highlighted to avoid the improper microwave application on starch or starch-based materials. Future perspectives of microwave processing of starch are suggested.

Starch metabolism in green algae

Abstract: Starch plays a central role in the life cycle as one of the principal sources of chemical energy. This polysaccharide accumulates in plastids in green algae and land plants, and both organisms have acquired various enzyme isoforms for each step of the metabolic pathway. Eukaryotic green microalgae present the critical photosynthetic functions as higher plants. However, due to the small size of their genome, gene redundancy is decreased, a feature that makes them an excellent model for investigating the properties of photosynthetic physiology. In the last decade, there has been an increasing demand for starch in many industrial processes, such as food, pharmaceutical, and bioethanol production. Thus, a better understanding of starch biosynthesis, in particular the structure–function relationship and regulatory properties of the enzymes involved in its production may provide a powerful tool for the planning of new strategies to increase plant biomass, as well as to improve the quality and quantity of this polymer.

Physicochemical and functional characterization of yam starch for potential industrial applications

Abstract: Yam is a significant and highly prized starchy crop in West and Central Africa, but largely underutilized industrially. Functional and physicochemical properties of starches extracted from forty-three varieties of Dioscorea rotundata, Dioscorea alata, Dioscorea dumetorum, Dioscorea cayenensis, and Dioscorea bulbifera were investigated for their potential industrial utilization. Water binding, swelling, gelation capacity, granule size, amylose/amylopectin, pasting characteristics, paste clarity, and syneresis were determined. Results showed that starches from D. rotundata, D. alata, D. cayenensis, and D. bulbifera had large starch granules (25–50mm) while D. dumetorum had small granules (7–12mm). There was variability in the starch granule shapes, which were mostly oval, round, and triangular. The least gelation concentration of the starches was between 4 and 16%. Paste clarity of the starches decreased as storage days increased and all the starches exhibited high syneresis indicating tendencies to retrograde on low storage temperature. There were differences in the pasting characteristics of the yam starches with D. rotundata and D. bulbifera having high peak viscosities compared to others. These differences in functional and physico-chemical properties of the yam starches are discussed as indicators of the various products for which they can be utilized in both food and non-food applications.

Preparation of corn starch–fatty acid complexes by high-pressure homogenization

Abstract: Aqueous mixtures of defatted corn starch and different fatty acids were heated and processed with high-pressure homogenization to form starch–lipid complexes. A variety of fatty acids with chain lengths of 12–18 carbons and with varying degrees of unsaturation were studied regarding their ability to form amylose–lipid complexes. Linoleic acid (65.7%) displayed the greatest complex forming ability with defatted corn starch, followed by lauric acid (63.2%), oleic acid (62.2%), myristic acid (61.2%), palmitic acid (59.8%), and stearic acid (54.6%). The XRD analysis showed that the complexes presented the well-known V-helical type diffraction. DSC was used to analyze the thermal properties. Based on the 85–110°C transition temperature and the 60–95°C synthesis temperature, the experimental complexes are less ordered type I complexes. The in vitro digestibility studies indicated that long-chain saturated fatty acids increased digestibility more than the short-chain saturated and unsaturated fatty acids when in complex with defatted corn starch.

20. The Extraordinary Science of Addictive Junk Food

Abstract: On the evening of April 8, 1999, a long line of Town Cars and taxis pulled up to the Minneapolis headquarters of Pillsbury and discharged 11 men who controlled America’s largest food companies. Nestle was in attendance, as were Kraft and Nabisco, General Mills and Procter & Gamble, Coca-Cola and Mars. Rivals any other day, the C.E.O.’s and company presidents had come together for a rare, private meeting. On the agenda was one item: the emerging obesity epidemic and how to deal with it. While the atmosphere was cordial, the men assembled were hardly friends. Their stature was defined by their skill in fighting one another for what they called “stomach share” — the amount of digestive space that any one company’s brand can grab from the competition.

Characteristics of starch obtained at different stages of purification during commercial wet milling of maize

Abstract: Characteristics of starch obtained at different stages of purification during commercial wet milling of maize were evaluated. L*, whiteness index, swelling power, transmittance and syneresis progressively increased while a*, b*, protein content, lipid content and water binding capacity of the starches decreased after each successive purification stage. Protein and lipids content decreased from 5.2 to 0.3% and from 0.15 to 0.03%, respectively, after each successive purification stage. SDS–PAGE indicated that high MW polypeptides eliminated during early stages of purification than low MW. The starches showed typical A-type XRD pattern along with increasing crystalline region after each successive purification stages. DSC evaluation showed the presence of two endotherms during heating, the first between 69.9 and 81.5°C and second endotherm between 84.1 and 105.3°C being associated with the melting of crystallites and amylose–lipid complexes, respectively. Transition temperatures decreased while gelatinization enthalpy increased with the purification of starch. During cooling, exotherms at peak temperature between 78.8 and 90.3°C was observed. Peak viscosity, final viscosity, breakdown viscosity and setback increased while pasting temperature decreased after each successive purification stage. Storage modulus, syneresis and transmittance of starches revealed increased tendency towards retrogradation with decrease in protein content and lipid content.

Impact of acid and heat–moisture treatment combination on physicochemical characteristics and resistant starch contents of sweet potato and yam starches

Abstract: The objective of this study is to investigate formation of slowly digestible starch (SDS) and resistant starch (RS) and change in physicochemical properties of sweet potato and yam starches under a combination of acid and heat–moisture treatments using three mild organic acids including acetic acid, lactic acid and citric acid and heating temperature at 110°C for 8 h. The results show that the SDS and RS in sweet potato starch significantly increased from 6.6 and 14.7% in native starch to 8.7–13.2% and 37.5–42.1% in acid and heat–moisture treated starches, respectively. Likewise, the SDS and RS in yam starch increased from 4.7 and 21.6% in native starch to 10.0–11.3% and 39.0–46.4% in the treated starches, respectively. The RS content in the acid and heat–moisture treated starches was also significantly higher than that of the heat–moisture treated starches without acid hydrolysis. Yam starch produced higher amount of RS under acid and heat–moisture treatment as compared to sweet potato starch at the same condition. Swelling power and viscosity of starches significantly decreased, whereas the solubility significantly increased after treatments. The citric acid had the most impact on RS formation and starch properties, followed by lactic acid and acetic acid. As a result, the combination of acid and heat–moisture treatment is a useful method to produce higher amount of resistant starch, which can be applied for functional foods.

Influence of cassia gum on rheological and textural properties of native potato and corn starch

Abstract: Pasting, rheological, and textural properties of potato and corn starch pastes and gels with different amounts of cassia gum were investigated. Significant effect of cassia gum on pasting characteristic of the starches was found. A decrease and an increase in peak viscosity of potato and corn starch systems, respectively, was observed with increase in cassia gum concentration. The final viscosity, extent of breakdown and setback viscosity were increasing with increasing cassia gum level in both starch systems. The effect of cassia gum on steady flow behavior of the starch pastes differed among the starches. However, all the systems with higher cassia gum concentration exhibited higher shear stress values than their control counterparts. The starch–cassia gum systems were classified as weak gels and their elastic properties were decreasing by the amount of cassia gum. Presence of cassia gum resulted in changes in textural properties of the starch gels, however, the changes were not always consistent with the increase in cassia gum concentration.

Effects of glycerol and storage relative humidity on the properties of kudzu starch‐based edible films

Abstract: Kudzu (Pueraria lobata) starch films were prepared using glycerol as plasticizer. The effects of glycerol (0, 10, 20, 30, and 40% of dry starch) and storage relative humidity (RH, 53, 75, and 100%) on molecular interactions, crystalline structural characterizations, and thermal stabilities of the films were investigated using Fourier transform-infrared (FT-IR) spectra, XRD, and thermogravimetry and DTA (TG-DTA). The results showed that kudzu starch could form intermolecular hydrogen bonds with glycerol and water molecules, and increasing RH could enhance the sensibility of CO bonds in COC groups to glycerol. The addition of glycerol promoted the formation of B-type and V-type crystal structure in plasticized film, whereas increasing RH impeded V-type crystal structure. Thermal stability decreased slightly as glycerol content and RH increased. Moreover, anti-plasticization was found from TG-DTA spectra and water sorption isotherms at low water activities. Furthermore, water vapor permeability (WVP) and mechanical properties of the films were also studied. The WVP values increased with increasing glycerol content and RH, and the lowest value was about 3.15 × 10−11 g m−1 s−1 Pa−1 for 20% glycerol plasticized film at 50% RH. The puncture strength of kudzu starch film ranged from 1.31 to 10.86 N and deformation ranged from 4.10 to 5.15 mm.

Production, purification, and characterization of thermostable α‐amylase from thermophilic Geobacillus stearothermophilus

Abstract: The α-amylase (α-1-4-D-glucan glucanohydrolase; EC 3.2.1.1) secreted by Geobacillus stearotermophilus was purified and characterized. Maximum enzyme production was achieved after 24 h cultivation at pH 7.0 and 55°C. The enzyme was active in a broad temperature range, between 50 and 80°C, with an optimum at 70°C; and maximum activity was at pH 7.0. The enzyme was purified using 80% ammonium sulfate precipitation, dialysis, Sephadex G-100 gel filtration, and DEAE-cellulose column chromatography, with a 46-fold and 65% recovery and showed a MW of 63 kDa by SDS-PAGE. It was determined that the purified enzyme was stable at 50 and 60°C, and pH 7.0. It was determined that the purified enzyme was stable at 50 and 60°C at the end of 2 h. The enzyme retained 100% activity pH 7.0 at the end of 3 h. The enzyme was activated by Ca2+, Mn2+, and Triton X-100, but strongly inhibited by Cu2+, Zn2+, Fe2+, and Hg2+. The enzyme follows Michaelis–Menten kinetics with Km and Vmax values of 0.051 mM and 1.424 μmol/min, respectively.

Citric acid modified potato starch films containing microcrystalline cellulose reinforcement – properties and application

Abstract: The preparation method of starch-based films cross-linked with citric acid (CA) and containing microcrystalline cellulose (MCC) has been described. The addition of MCC improved mechanical properties of polysaccharide films. Young's modulus and tensile strength increased from 42 to 96 MPa and from 2.6 to 3.9 MPa, respectively, for unfilled starch/CA films and similar system containing 15 wt% MCC, respectively. Moreover, the presence of cellulose filler influenced the thermal properties of starch-based material: with increasing MCC content glass transition (tan δ) increased from 108 up to 129°C, respectively, for unfilled system and containing 15 wt% MCC. Additionally, the hydrophilicity of starch-based films was reduced, as moisture absorption and solubility in water decreased. Novel application of reinforced biodegradable starch-based films as pressure sensitive adhesive carrier (for double-sided tapes used in paper industry) was successfully proposed.

Starch physicochemical properties of waxy proso millet (Panicum Miliaceum L.)

Abstract: Starches of four varieties of waxy proso millet were examined in terms of granule morphology, amylose, transparency, retrogradation, pasting, and thermal properties. The starches had great numbers of large polygonal granules with smooth edges, small numbers of small spherical granules, and an average granule size of 6.12 µm. Compared with the starches of non-waxy proso millet and maize, the starches of the waxy proso millet varieties had lower amylose contents (0.21%) and higher phosphorus contents (1.85 mg/100 g); higher transparency (29.84%) and lower volume percentages of retrogradation (5.01%); higher peak viscosities (3304 cP), trough viscosities (2422 cP) and breakdowns (882 cP), and lower setbacks (267 cP); and lower onset temperatures (To) (69.7°C), peak temperatures (Tp) (75.3°C), final temperatures (Tc) (80.8°C) and enthalpies (ΔH) (10.55 J/g) in their starch gelatinization.

Physicochemical properties of starch extracted from Colocasia esculenta (L.) Schott (Bun‐long taro) grown in Hunan, China

Abstract: Taro ( Colocasia esculenta (L.) Schott) starch was extracted from the corms of Bun-long taro cultivated in Hunan, China, and its physicochemical properties were determined and compared with those of potato and sweet potato starches. Bun-long taro starch had an irregular, polygonal shape, and grains were small in size: the surface-average granule diameter ranged from 1.3 to 2.2 µm. Amylose content in Bun-long taro starch was 8.4 ± 0.2%, determined by dual-wavelength colorimetry, and the starch had an A-type XRD pattern. The onset temperature ( T o ), peak temperature ( T p ), and completion temperature of gelatinization ( T c ) associated with Bun-long taro starch were 73.6, 80.3, and 88.3°C, respectively, determined by DSC. According to the Brabender amylograph paste viscosity analysis, the viscosity of Bun-long taro starch started increasing at 77°C, which was higher than the temperatures at which the viscosities of potato starch and sweet potato starch started increasing.

Mechanical properties and delivery of drug/probiotics from starch and non-starch based novel bigels: A comparative study

Abstract: The current study explores the properties of starch and non-starch polysaccharides based bigels containing sunflower oil and their application in controlled delivery of metronidazole and probiotics. The bigels were prepared by mixing span-40 and sunflower oil organogels with the aqueous polysaccharide sol. The microstructure of the bigels was characterized by fluorescent microscope. The bigels were then characterized for their mechanical properties using texture analysis. The flow behavior of the gels was studied using rheometer. The micrographs suggested uniform distribution of the organogels in the continuous aqueous phase. The bigels were viscoelastic in nature with a shear thinning behavior. The release of metronidazole from the bigels was diffusion mediated. These bigels showed good antimicrobial efficacy. The probiotics encapsulated within the bigels were tolerant to gastric and intestinal environment compared to the free cells. The preliminary studies suggest that the developed bigels can be used effectively for the delivery of poorly soluble drugs and probiotics.

Comparison of morphological changes and in vitro starch digestibility of rice cooked by microwave and conductive heating

Abstract: This study was aimed at evaluating the effect of two cooking methods on in vitro digestibility of starch and the change in its microstructure. Rice was cooked by microwave and conductive heating (CH), then stored at −18, 4, 25°C, the in vitro digestibility of starch was measured by in vitro simulative digestion method and the micromorphology was obtained by SEM. Rice starch heated by microwave had greater swell and smaller gaps between starch granules when compared with that heated in a conductive way. The concentrations of reducing sugar and glucose of in vitro digestibility of the rice starch cooked by microwave heating (MH) are higher than that by CH (p≤0.01). After storage, the in vitro digestibility of starch lowered, namely, the content of rapidly digestible starch (RDS) decreased, however, the content of slowly digestible starch (SDS) and resistant starch (RS) increased. After 72 h of storage the in vitro digestibility of rice starch cooked by MH was inferior to that by CH. The higher the storage temperature was, the worse the in vitro digestibility of starch was. This applied to both heating methods. The best digestibility effect was achieved when the rice was cooked by MH and stored at −18°C. Meanwhile, the kinetic model of in vitro digestibility of starch demonstrated that the equilibrium percentage and kinetic constant of the reducing sugar and glucose declined as the storage time increased.

Acid modification of wheat, potato, and pea starch applying gentle conditions—impacts on starch properties

Abstract: Acid-thinned wheat, potato, and pea starch products were systematically prepared applying gentle conditions with variation of acid type (HCl and H2SO4), acid concentration (0.36 and 0.72 N in a 40% (w/w) suspension) as well as hydrolysis time (4 and 24 h). Starch granule properties as well as molecular and rheological characteristics in the solution state were analyzed and the impact of all parameters varied was found to be immense. Carbohydrate solubilization of wheat and potato starch was significantly higher compared to pea starch. Noteworthy progress in solubilization was found when hydrolyzed with HCl, and with increasing acid concentration and increasing hydrolysis time by trend. The hydrolysis affected the reduction of the hot paste viscosity most dominant in the first period of treatment (0–4 h), however, size exclusion chromatography-multi angle laser light scattering (SEC-MALS) analysis revealed a more prominent molecular degradation during the second period (4–24 h). This observation led to the interpretation that the molecular degradation in the initial phase results particularly in “debranching” of the high molar mass amylopectin fraction and lower hot paste viscosity. Continued hydrolysis with significant reduction of the molecular size, however, had reduced impact on further lowering of viscosity. SEM micrographs displayed intact pea starch granules with unchanged surface after hydrolysis, whereas wheat and potato starch granules were visibly affected with damage not evenly distributed but a variation over the granule population. Granular wheat and potato starch exhibited significantly enhanced particle size after short period modification measured in water. However, this was found eliminated at extended hydrolysis time. Reasons were hydrolysis induced molecular rearrangement resulting in better crystalline packing on the amorphous/crystalline threshold reducing the ability to swell, and the progress in granular erosion. That was in line with changed swelling characteristics determined using DSC. The study gave evidence for strong impact of acid hydrolysis on functional properties like water binding.

Structural, thermal, and rheological properties of Amaranthus hypochondriacus and Amaranthus caudatus starches

Abstract: Structural, thermal, and rheological properties of starches from 13 Amaranthus hypochondriacus lines and 8 Amaranthus caudatus lines were evaluated and related using principal component analysis. Amylopectin chains with DP 6–12, DP 13–18, DP 19–24, and DP 25–30 ranged from 43.60 to 55.72%, 31.59 to 34.49%, 10.14 to 16.37%, and 2.56 to 5.53%, respectively, for A. hypochondriacus and 50.67 to 57.53%, 29.30 to 32.02%, 10.04 to 13.09%, and 2.75 to 4.2%, respectively for A. caudatus. A. hypochondriacus showed higher proportion of granules <1 µm (14.76–35.64%) than A. caudatus (0.16–6.92%). A. hypochondriacus and A. caudatus starches showed the granules of size 1–10 µm between 57.09 to 77.48% and 88.67 to 99.66%, respectively. The transition temperatures (To, Tp, and Tc) were negatively correlated with amylopectin short chains (DP 6–12). The pasting properties (PV, BV, FV, and SB) were positively correlated with DP 6–12 and negatively with DP 13–24. Starches with higher proportion of granules of 1–10 µm showed higher amount of DP 6–12, crystallinity, and paste viscosities. Starches with higher proportion of 11–30 µm had high DP 13–30 and gelatinization transition temperatures. The results reflected that the change in structure from liquid-like to solid-like was dependent upon chain length, starch with higher DP 6–10 showed higher Tcrossover (temperature at which G′ became higher than G″ during heating) and those with higher DP 13–24 showed lower Tcrossover.

Functional properties of cowpea ( Vigna unguiculata ) starch as modified by guar, pectin, and xanthan gums

Abstract: In the present study, the effect of different hydrocolloids (guar, xanthan, and pectin) were evaluated on some functional properties of cowpea starch. It was found that these hydrocolloids significantly enhanced the water absorption while reducing the swelling power and solubility. Only pectin was found to be an effective gum which reduces the syneresis of the cowpea starch gel during freeze–thaw process. The results indicated that guar gum caused a noticeable increase of peak viscosity as well as viscosity at 95°C examined by viscoamylograph whereas reducing trend was observed for both peak viscosity and viscosity at 95°C when pectin was added. It was also observed that guar gum caused a rapid rise in viscosity during the cooling period whereas the addition of the xanthan as well as pectin dropped the viscosity of cowpea starch. The heating stability of cowpea starch was found to be reduced by the addition of guar and xanthan gums while set back capability was successfully reduced by all selected hydrocolloids. The firmness of cowpea starch gel could be improved by the addition of all selected hydrocolloids during storage as compared to native starch.

Crosslinked thiolated starch coated Fe3O4 magnetic nanoparticles: Effect of montmorillonite and crosslinking density on drug delivery properties

Abstract: The anti-tuberculosis drug isoniazid was incorporated within crosslinked thiolated starch coated magnetic iron oxide nanoparticles, aiming to reach a controlled drug delivery system. The coated magnetic nanoparticles were characterized by FTIR, XRD study, and Vibrating Sample Magnetometer (VSM). The morphology and dimensional characteristics of the nanoparticles were analyzed by SEM, TEM, and Dynamic Light Scattering (DLS) method. The drug release mechanism was studied at pH 1.2 and pH 7.4 for different time periods by UV–visible spectrophotometer. Cytotoxicity study was performed by MTT assay analysis. Mucoadhesivity study was done by in vitro wash-off and ex vivo mucoadhesive test. The incorporation of montmorillonite and crosslinking of the nanoparticles were found to improve the cell viability, mucoadhesivity, and drug release properties. The properties of the prepared nanoparticles suggested their prospects for biomedical applications.

Evaluation of various chemical and thermal feed processing methods for their potential to enhance resistant starch content in barley grain

Abstract: Controlling the digestibility of starch in cereals by enhancing the content of RS has attracted considerable attention because of its health-promoting properties. Main goal of this research was to establish the role of different chemical and thermal processing methods on their potential to enhance RS content and modulate chemical composition of barley grain. A combination of 28 chemical and thermal grain processing techniques, including water and different lactic (LA) and tannic acid (TA) concentrations, steeping durations, with or without heat (55°C) and post-cooling conditions were compared with untreated native barley. Treating barley grain with 5% LA for 48 h at room temperature was the most efficient method to enhance RS proportion (3.1% of DM) in barley grain, which was five times higher than RS of native barley. Greater RS contents were also associated with elevated proportions of organic matter and total fiber in the barley grain. In vivo animal studies are warranted to evaluate this processing method from nutritional and health-enhancing perspective.

Radiation synthesis and characterization of starch-based hydrogels for removal of acid dye

Abstract: Aseries ofhydrogelsbasedonstarch,acrylicacid(AAc) and2-hydroxyethylmethacrylate (HEMA), namely AAc/starch and AAc/HEMA/starch hydrogels were synthesized by gamma radiation and used to adsorb acid fast red dye from aqueous solution. Alkali treatment of AAc/starch hydrogels to improve their ionic character was evaluated. The structure and surface morphology of prepared hydrogels were confirmed by Fourier transfer infrared spectra and SEM, respectively. The results indicated that the diffusion of water into the hydrogels pertains a non-Fickian character. The swelling equilibrium for AAc/starch and NaAc/starch hydrogels was obtained after 10h whereas for AAc/HEMA/starch hydrogels after 5h. The effects of the medium pH, initial dye concentration and temperature on the adsorption were studied. The adsorption capacity increases with increasing dye concentration and decreasing medium pH. The increase of temperature leads to higher adsorption capacity for AAc/starch and NaAc/starch hydrogels but lower adsorption capacity for AAc/HEMA/starch hydrogels.

Physicochemical properties of lipase-catalyzed laurylation of corn starch

Abstract: Corn starch was esterified with lauric acid by using lipase as catalyst in low moisture. The physicochemical and granular properties of esterified starches were determined, including transmittance, syneresis, swelling power, solubility, and thermal analysis, as well as SEM and XRD analysis. The amylose content of esterified starches was in the range of 47.31–48.69%, corresponding with the degree of substitution (DS) ranging from 0.0033 to 0.0151. There was a significant increase in syneresis, swelling power, solubility, and gelatinization temperature, but a decrease in transmittance of esterified starches. The results of SEM and XRD analysis revealed that esterification led to apophyses and pores on the surface of starch granules, but caused few changes in the crystalline structure of esterified starch (DS = 0.0109, 0.0151). Thermal gravimetric analysis (TG) indicated that the esterified starch showed thermal instability compared with native starch.

Microwave mediated preparation of nanoparticles from wx corn starch employing nanoprecipitation

Abstract: 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.