Partial Gelatinization Research Articles

Improvement of pasting and gelling behaviors of waxy maize starch by partial gelatinization and freeze-thawing treatment with xanthan gum

To improve the pasting and gelling behaviors of waxy maize starch, an aqueous dispersion with or without xanthan gum was subjected to partial gelatinization (5 ℃ above the onset melting temperature of starch) and freeze-thawing treatment. After the treatments, starch granules were slightly deformed, with partial loss of birefringence, and tended to aggregate. The relative crystallinity and thermal stability of waxy maize starch crystals decreased by the treatments. These changes indicated that the treatment affected the inner structure and chain arrangement of the granules. The treated waxy maize starches, however, showed a higher overall pasting viscosity with shorter and more cohesive pastes than that of the native starch. The treated starches formed rigid gels with increased stability against freeze-thawing. The addition of small amounts of xanthan gum enhanced the effects of the treatments.

The effect of heat-moisture treatment conditions on the structure properties and functionalities of potato starch

Potato starch was modified via heat-moisture treatment (HMT) under various reaction conditions. The effect of HMT on structural, physicochemical, and in vitro digestibility were investigated. HMT led to the rupture, adhesion and partial gelatinization, and agglomeration of the granules which surface became rougher, thereby increasing the particle size and resulting in the hollow structure located at the hilum of potato starch granules. XRD results showed an increased relative crystallinity and transformed crystalline structure from B-type to C-type with the extension of heat moisture treatment. FTIR spectroscopy results indicated that HMT might cause additional interactions between amylose-amylose, and/or amylose-amylopectin and/or amylopectin-amylopectin chains, which eventually leads to the increase of the mass of the carbonyl group and a hydroxyl group. HMT significantly decreased the peak viscosity, hold viscosity, and breakdown viscosity of starch, while the gelatinization temperature increased. The tHMT1, THMT100, and CHMT15 had the lowest content of RDS and there was no significant difference between the three samples, that is these three samples had the highest total content of SDS and RS.

Infusion efficiency of fluorescein derivatives of different molecular sizes into various starches under atmospheric and high hydrostatic pressures.

The online version contains supplementary material available at 10.1007/s10068-021-00972-2.

Impact of superheated steam on the moisture transfer, structural characteristics and rheological properties of wheat starch

Superheated steam treatment (SST) can improve cereal-based foodstuff quality. Starch is the major component of cereal-based foodstuffs, playing a key role in food quality. For understanding the effect of SST on the moisture distribution, lamellar structure and molecular weight of wheat starch, the low-field nuclear magnetic resonance (LF-NMR), small angle X-ray scattering (SAXS) and size exclusion chromatography were employed. Compared with native starch, SST reduced the average thickness of crystalline layer and induced the depolymerization of starch molecules, which were attributed to the limited moisture transfer resulting in the partial gelatinization of starch granules. The structural variations had a synergistic effect on the rheological properties of starch samples. Upon SST, treated samples exhibited a weaker pseudoplasticity behavior and increased the deformability and mobility of gels systems. Furthermore, the lower tanδ values of treated starch samples were observed, indicating that the gels systems tended to the solid-like behaviors.

Morphology, pasting, and structural characteristics of potato starch/xanthan gum blend by critical melting and freeze-thawing treatment

An aqueous suspension of native potato starch (PS)/xanthan gum (XG) mixture was subjected to physical treatments, including critical melting (mild heating, MH; partial gelatinization, PG) and freeze-thawing (FT) treatments. The Physical treatments significantly changed the morphology, pasting, and structural characteristics of potato starch compared with the simple aqueous blending of PS and XG. Microscopy revealed that the starch granules partially melted and some of the melted granules aggregated into a cluster after critical melting and FT treatment. The overall intensity of X-ray diffraction peaks and relative crystallinity also decreased obviously after treatment, indicating partial disruption of the starch inner structure. Both XG addition and physical treatment decreased the solubility index, swelling power, and water holding capacity of starch after physical treatments. Moreover, the final viscosity (from 2988 to about 5000 mPa s) and shear stability (from 3542 to about 200 mPa s) of starch paste were substantially increased by the physical treatments. The critical melting caused the leaching of soluble starch, which induced the formation of starch/XG aggregate matrix attached to the surface of starch granules during FT treatment, contributing to the starch property modification. While the formation of these matrices might also be the reason for the increased thickness of the starch semi-crystalline lamellar structure.

Application of partial gelatinization autoclaving-cooling process to increase the resistant starch content of fermented cassava pulp flour-based composite flour

Fermented cassava pulp flour-based composite flour (FCPF-based composite flour) is a composite flour consisting of fermented cassava pulp flour, cassava starch, and xanthan gum which has the potential to be developed as a gluten free flour. This study was aimed to increase the resistant starch (RS) content of FCBF-based composite flour through the application of the partial gelatinization (PG) autoclaving-cooling process. Other aims were to characterize its chemicals properties, granular morphology, polarized optical microscopy, amylographic profile, X-ray diffraction pattern and relative crystallinity, degree of starch hydrolysis, and estimated glycemic index (EGI). The results of the study revealed that PG autoclaving for 15 min and cooling time 72 h was the optimal treatment that increased the RS content of FCPF-based composite flour from 1.75% to 7.31%. This study indicated that the increasing of resistant starch content of FCPF-based composite flour changed its chemicals properties, granular morphology, polarized optical microscopy, amylographic profile, X-ray diffraction pattern and relative crystallinity; and lowering the degree of starch hydrolysis and value of estimated glycemic index (EGI). Increased the RS content would improve the functional properties of FCPF-based composite flour

Rotary-moulded biscuits: Dough expansion, microstructure and sweetness perception as affected by sucrose:flour ratio and sucrose particle size

Abstract Sucrose not only provides sweetness, but also modifies the thermal/viscoelastic behavior of dough during baking. Most research on biscuit manufacturing has been focused on sugar-snap and wire-cut biscuits, and there is a lack of accumulated knowledge with respect to rotary-moulded biscuits. The aim of this study was to analyze the effect of the sucrose:flour ratio and the particle size of sucrose on dough expansion and starch gelatinization during the baking of rotary-moulded biscuits, together with their link to sweetness perception. X-ray micro-CT and scanning electron microscopy were used to ascertain the link between sensory attributes and biscuit structural properties. Image analysis showed that biscuits with lower levels of sucrose resulted in a microstructure with smaller air pores and thinner walls, which may be related to a lower degree of grittiness and hardness at the first bite. Furthermore, the results revealed the partial gelatinization of starch in all formulations, along with a gelatinization degree that increased from 6 % to 40 % as the sucrose content decreased from 40 % to 10 % (d.b.). Interestingly, biscuits that were formulated with powdered sucrose at the highest concentration attained an expanded and non-collapsible structure, a behavior that could be linked to the low degree of starch gelatinization.

Superheated steam pretreatment of rice flours: Gelatinization behavior and functional properties during thermal treatment

The effect of superheated steam pretreatment on the gelatinization behavior and functional properties of waxy and non-waxy rice flour were studied. The superheated steam-treated waxy rice flours and non-waxy rice flours showed significantly lower onset of gelatinization temperatures (58.8 and 56.1 °C, respectively) than that of their respective control. Water binding capacity, swelling power, solubility and particle size of rice flours were evaluated from 20 to 90 °C. Before the gelatinization temperature (<60 °C), the water binding capacity and swelling power were about 1.7 times higher for the superheated steam treated waxy rice flour and 1.4 times higher for the superheated steam treated non-waxy rice flour than those of their control. The superheated steam treated non-waxy rice flour had a significantly higher particle diameter (82 μm) than the other flours. The granules of superheated steam-treated flours were swollen more than the native flours granules due to partial gelatinization. Superheated steam may be a promising physical method for modification of specific properties of rice in terms of gelatinization behavior, granular structure and functional characteristics of rice flours.

Physicochemical, crystalline characterization and digestibility of wheat starch under superheated steam treatment

This paper explored the impact of superheated steam (SS) treatment on the physicochemical, crystalline characteristics and in vitro digestibility of wheat starch. Upon SS treatment, treated samples showed lower swelling power, solubility, and viscosities, but had higher gelatinization temperature, which might be due to the partial gelatinization of starch granules. This agreed with micromorphology characterization, indicating the degradation of Maltese cross. In addition, SS treatment decreased the long-range crystalline and short-range order of starch, compared to native starch sample. This change of physicochemical and structural properties was responsible for the decrease of starch hydrolysis rate. Meanwhile, SS treatment obviously increased the slowly digestible starch (SDS) and resistant starch (RS) content from 10.6% to 7.9% (native starch) to 17.2% and 13.6% (150 °C, 1 min), respectively. This knowledge indicates that superheat steam technology possibly is a promising strategy in starch modification.

Changes in the Glutinous Rice Grain and Physicochemical Properties of Its Starch upon Moderate Treatment with Pulsed Electric Field.

Pulsed electric field (PEF) processing is an emerging non-thermal technology that shows potential to improve food quality and to maintain stability. Glutinous rice is composed mainly of amylopectin and has low amylose content. This study investigated the effect of PEF treatment at 3 kV/cm field strength for 50 to 300 pulses on whole, water-soaked glutinous rice grains. Micro-pores were created at the surface of PEF treated rice grains, increasing grain porosity from 7.3% to 9.8%. Peak viscosity of PEF treated rice flour decreased, and breakdown, final and setback viscosities increased as the number of PEF treating pulses increased, indicating that the swelling degree of rice starch was promoted after PEF treatment. Lower values of gelatinization enthalpy and lower crystalline degree of PEF treated glutinous rice flour were also observed. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) studies confirmed the secondary structure changes in rice protein and partial gelatinization of rice starch after PEF treatment.

Effect of extruded starches on the structure, farinograph characteristics and baking behavior of wheat dough

Extruded wheat starch (ES) was obtained by a single-screw extruder to determine its effect on the farinograph, structural properties and baking behaviors of wheat dough. XRD analysis showed that increasing extrusion temperature made the crystalline peaks less pronounced due to the partial gelatinization. In terms of FTIR results, the molecular order of extruded starch was lower than that of native starch. The dough development time was decreased from 3.2 min to 2.7 min while the stability time was increased from 14.4 min to 15.5 min, as 70 ES were added. It was accompanied with increasing levels of α-helix and β-turn transferred from the decreased content of random coil and β -sheet. These effects in bread were to increase loaf volume and reduced loaf hardness. These results indicated that extruded starch had a good potential for producing a high-quality bread.

Effect of low pressures homogenization on the physico-chemical and functional properties of rice flour

Research was conducted to explore the use of low pressure homogenization for extending functionality of rice flours. The impact of low pressure homogenization (0, 30, 50 MPa and 0, 1, 2, 3 passes) on the particle size distribution of long (LRF) and medium (MRF) rice grain flour was evaluated. The pressure level and the number of passes resulted in a lower particle size in both rice flours. Higher pressures and 3 passes led to an increase in the particle size due to aggregation of smaller particles. The effect of low pressure homogenization (0, 30 or 50 MPa - 3 passes) on the physicochemical (composition, bulk density, thiol groups, hydration, emulsifying properties, hydrophobicity, crystallinity) thermal and pasting properties was analyzed. Homogenization increased swelling, oil absorption capacity and surface hydrophobicity of LRF and MRF samples even at 30 MPa. The bulk density and the emulsion stability of samples decreased by pressure. However, the emulsifying activity and thiol groups did not change in LRF, while increased in MRF particularly at 30 MPa. SEM micrographs revealed the microstructure changes, but no significant differences were observed in starch crystallinity. FTIR spectra suggested the modification of the flour constituents, particularly in MRF, reaching higher intensities. The disintegration and modification of the large molecules, increasing availability of binding sites, and partial gelatinization of starch granules, led to flours with different pasting performances. Correlation analysis confirmed that the particle size reduction played a determinant role in the structural and physicochemical changes of both rice flour varieties used.

Physical modification of various starches by partial gelatinization and freeze-thawing with xanthan gum

Aqueous dispersion (40% w/w, dry basis) of different starches (corn, potato, and tapioca), with or without xanthan gum (0.1% w/w, based on starch solids), were partial gelatinizated for 1 h at 5 °C above the onset temperatures of starch and cooled (GC), freeze-thawed (FT), and then dried at 60 °C. The combined treatments (GCFT) raised the viscosity and shear stability of starch pastes. Among the starches tested, potato starch exhibited the greatest changes in the pasting behavior. In addition, the physical treatments (GCFT) improved the gelation behavior and the stability against repeated freeze-thawing cycles. A minor addition of xanthan gum enhanced the effect of physical treatments, especially on the stabilization of starch gels.

Influence of Partial Gelatinization Treatment on the Quality Changes of Puffed Rice

The objective of this study was to examine the quality enhancement of puffed products made with partial gelatinized waxy and non-waxy type rice. The partial gelatinization process increased water holding capacity of samples, regardless of the gelatinization time, with the puffed waxy rice exhibiting higher water holding capacities than the puffed non-waxy rice. The hardness of puffed rice using partial gelatinized waxy or non-waxy type rice was lower compared with non-partial gelatinized samples. Partial gelatinization also increased the final viscosity of the samples, which was decreased by the puffing treatment. The setback viscosity was higher in the partially gelatinized rice than in the non-gelatinized rice and was lower for the puffing treatment. The in vitro starch digestibility of waxy and non-waxy type rice was improved by a puffing treatment. These results suggest that puffed rice using partial gelatinization treatment enhances the quality and digestibility of soft-textured foods.

One-step microwave curing-dehydration of Gastrodia elata Blume: Relationship between phytochemicals, water states and morphometric characteristics

Gastrodia elata Blume – an important medicinal crop widely cultivated and used in Asian countries especially China, when favorably dried can give high recovery/yield of its bioactive compounds. Traditionally, gastrodia tubers are processed (cured) before drying to increase their bioactive phytochemical constituents, most importantly gastrodin. Since, the conventional method is tedious and time-consuming, the current work investigates a rapid single step post-harvest curing-drying method based on microwave to achieve high yields of gastrodin from gastrodia. HPLC analysis depict that microwave drying (MWD) increased the total phenolic content by 3.4 times compared with conventional techniques. Drying kinetics depicted that MWD dehydrated gastrodia in 2 h compared with 48−59 h by conventional processes. Minimum change in surface color (ΔE: 5.8 ± 0.02) and highly porous internal structure was observed in MWD samples compared with conventionally dried samples. Low power microwave energy (100 W) yielded more phytochemical content than higher powers. UPLC/Q-TOF MS analysis of MWD gastrodia identified gastrodin and 14 other compounds. According to Spin-spin relaxation times (T2) by LF-NMR, only bound water was present in fully dried samples, whereas all 3 water states were found in fresh and half-dried samples. Scanning electron micrographs (SEM) showed honey-comb internal microstructure of MWD samples with distinct vascular tissues. 3-dimensional volume datasets (3D X-ray) depicted porosity and pore space arrangements inside samples before and after MWD. MWD also affected the intrinsic starch and enzymes in gastrodia causing variations to phytochemicals. FTIR spectra of starches from dried gastrodia tubers indicated changes in ordered crystallinity indicating partial gelatinization during drying. Moreover, MWD also inactivated enzymes (β-D-glucosidase) that hydrolyze gastrodin to p-hydroxybenzyl alcohol, thus preventing its hydrolysis. Therefore, it was observed that MWD is a simple, rapid, economical and benign alternative technique to dry gastrodia than other conventional methods.

Effect of dual chemical modification on the properties of biodegradable films from achira starch

AbstractThe objective of this study was to evaluate the effect of a dual modification (acid hydrolysis and succination) on the structural, mechanical, thermomechanical, and permeability properties of films from achira starch. Micrographs of films revealed a smooth surface and some remnants of starch granules, indicating a partial gelatinization. Tensile strength and percentage of elongation increased in films from double modified starch (10.50 MPa and 42.83%, respectively). The OH groups formed in the amylose and amylopectin chains during the hydrolysis and the alkoxide groups (RO−) generated during the succination resulted in high values of water vapor permeability (3.215 × 10−10 g/s m Pa). The glass transition temperature (Tg) of films from hydrolyzed–succinated starch was decreased due to the reduction of the molecular weight of the polymeric chains and the presence of succinate groups that reduced the molecular interactions of the polymeric chains, increasing the mobility and therefore decreasing the softening temperature.

Effects of annealing time on structure and properties of sweet potato starch

AbstractBackground and objectivesSweet potato starch is an important industrial raw material, but it is not applied widely because of its disadvantages including high regeneration rate and poor paste stability. In this study, the starches were incubated at 50°C for 1, 3 and 5 days, their structure and properties were determined, and annealing (ANN) time effects on sweet potato starch were investigated.FindingsX‐ray diffraction revealed that both native and annealed sweet potato starches had the A‐type crystalline pattern. After ANN for 3 days or less, the relative crystallinity, short‐range order and enthalpy of starch decreased slightly due to partial gelatinization, however long ANN for 5 days resulted in their increase. ANN increased the pasting temperature (To, Tp, Tc), narrowed the gelatinization temperature range (Tc‐To), and promoted an increasingly significant reduction in peak viscosity, breakdown, and setback with the increase in ANN time. Also, ANN increased the cumulative particle size of sweet potato starch granule.Conclusion5 days' ANN treatment had the greatest effect on the starch, while short‐time ANN for 1 day and 3 days had only the little effect. Right ANN time could obviously improve the starch structure and properties, like good thermal stability and weak retrogradation.Significance and noveltyThis study provides valuable conclusions from the ANN time level, confirms that long‐time ANN is very necessary, and creatively proved by the short‐range order and cumulative particle size.

Formulation and attributes of gluten-free cakes of Andean corn improved with green banana flour.

The aim of this work was obtaining layer and sponge cakes formulated with corn flour replaced by green banana flour and to determine the best substitution proportions to achieve nutritionally improved products and with texture and sensory characteristics acceptable. The replacement of corn flour by GB flour increased the density in layer cake batters, while in sponge cake batters the density decreased. The batters were influenced by the increase in the flow properties, the viscoelastic behaviour, and the decrease in the thixotropic properties. The thermal analysis of batters determined a partial gelatinization of the starch, which together with its rheological properties influenced the cakes' texture parameters. The substitution of 30% corn flour by GB flour in sponge and layer cakes produced a decrease in cohesiveness and an increase in hardness. In sponge cakes, incorporation of up to 30% of GB flour improved the sensory attributes and the textural properties, while in layer cakes a 30% substitution did not significantly deteriorate the quality of cakes.

Understanding the structural and digestion changes of starch in heat-moisture treated polished rice grains with varying amylose content

Although the effects of heat-moisture treatment on starch structures and digestibility have been evaluated, the changes in structures and digestion of starches in heat-moisture treated starch-based food systems with varying amylose contents are not well understood. In the present study, starches isolated from heat-moisture treated polished rice grains were characterized with multi-scale structures and digestibility to reveal the effect of amylose in rice grains on structures and digestibility of starch subjected to heat-moisture treatment. Results indicated that heat-moisture treatment contributed to the partial gelatinization of starch granules, but also significantly reinforced the molecular interactions between starch molecules and thus increased starch resistance to hydrothermal treatment and enzymes attack. The higher amylose content of the native starch was, the greater reduction in digestion was observed for heat-moisture treated starch. Pearson's correlation matrix showed that the amylose content highly correlated with the changes in structural features (e.g., molar mass, short-range ordered structure, crystalline structure, and lamellar structure) of starches followed by heat-moisture treatment. The amylose promoted the reinforcement of interactions between starch chains during heat-moisture treatment and then significantly contributed to the reduction in starch digestibility.

Reduction of Deoxynivalenol in Wheat with Superheated Steam and Its Effects on Wheat Quality.

Deoxynivalenol (DON) is the most commonly found mycotoxin in scabbed wheat. In order to reduce the DON concentration in scabbed wheat with superheated steam (SS) and explore the feasibility to use the processed wheat as crisp biscuit materials, wheat kernels were treated with SS to study the effects of SS processing on DON concentration and the quality of wheat. Furthermore, the wheat treated with SS were used to make crisp biscuits and the texture qualities of biscuits were measured. The results showed that DON in wheat kernels could be reduced by SS effectively. Besides, the reduction rate raised significantly with the increase of steam temperature and processing time and it was also affected significantly by steam velocity. The reduction rate in wheat kernels and wheat flour could reach 77.4% and 60.5% respectively. In addition, SS processing might lead to partial denaturation of protein and partial gelatinization of starch, thus affecting the rheological properties of dough and pasting properties of wheat flour. Furthermore, the qualities of crisp biscuits were improved at certain conditions of SS processing.