Retrogradation Of Rice Starch Research Articles

Effect of the Ratio of Soluble and Insoluble Dietary Fiber from Rice Bran with Extrusion Cooking Treatment on Pasting, Thermal, and Structural Properties of Rice Starch Gel

AbstractThis study aims to investigate the effect of different ratios of soluble and insoluble dietary fiber (0/100, 25/75, 40/60, 55/45, 70/30, 85/15, 100/0) in rice bran treated with or without extrusion cooking on the physicochemical and structural properties of rice starch. As the ratio of soluble dietary fiber (SDF) increases, the PV (peak viscosity), FV (final viscosity), SB (setback value), and BD (breakdown value) of starch are significantly decreased, indicating that a higher SDF ratio can delay the short‐term retrogradation of starch. Compared with the unextruded rice bran SDF/IDF starch gel, the content of weak bond water and free water in the extruded rice bran SDF/IDF starch gel is higher while the content of strong bond water in the starch gel is lower at the same SDF/IDF ratio. Meanwhile, for the results X‐ray diffraction (XRD) and fourier transform infrared spectrum (FTIR), the rice starch with the extruded rice bran SDF/IDF ratio of 25:75 shows the lowest relative crystallinity of 3.48% and the lowest peak to height ratio of FTIR (1047 cm−1/1022 cm−1) of 1.0746, suggesting that the inhibition effect on rice starch retrogradation is better. This may be beneficial for the utilization of different ratios of SDF/IDF from extruded rice bran and physicochemical properties improvement of rice starch gel.

Effect of different chain-length fatty acids on the retrogradation properties of rice starch

In order to delay the retrogradation of rice starch, the effects of three different chain length fatty acids (lauric acid, myristic acid and palmitic acid) on rice starch were studied. The fatty acids with longer carbon chains had strong steric hindrance and hydrophobicity, which formed a more compact structure in the helical cavity of amylose, and significantly reduced degree of expansion, migration of water, short-range ordered structure, number of double helical structures and crystallinity. These structural changes endowed the rice starch-long chain fatty acid complexes with better gel viscosity, liquid fluidity and thermal stability than in the rice starch-short chain fatty acid complexes. The results showed that fatty acids with longer chain length inhibited the retrogradation of rice starch, most obviously when 5% palmitic acid was added. This study provides an important reference for the processing of rice starch-based foods.

Moisture Sorption Isotherms of Polydextrose and Its Gelling Efficiency in Inhibiting the Retrogradation of Rice Starch.

As an anti-staling agent in bread, the desorption isotherm of polydextrose has not been studied due to a very long equilibrium time. The adsorption and desorption isotherms of five Chinese polydextrose products were measured in the range of 0.1-0.9 aw and 20-35 °C by a dynamic moisture sorption analyzer. The results show that the shape of adsorption and desorption isotherms was similar to that of amorphous lactose. In the range of 0.1-0.8 aw, the hysteresis between desorption and adsorption of polydextrose was significant. The sorption isotherms of polydextrose can be fitted by seven commonly used models, and our developed seven-parameter polynomial, the adsorption equations of generalized D'Arcy and Watt (GDW) and Ferro-Fontan, and desorption equations of polynomial and Peleg, performed well in the range of 0.1-0.9 aw. The hysteresis curves of polydextrose at four temperatures quickly decreased with aw increase at aw ˂ 0.5, andthereafter slowly decreased when aw ≥ 0.5. The polynomial fitting hysteresis curves of polydextrose were divided into three regions: ˂0.2, 0.2-0.7, and 0.71-0.9 aw. The addition of 0-10% polydextrose to rice starch decreased the surface adsorption and bulk absorption during the adsorption and desorption of rice starch, while it increased the water adsorption value at aw ≥ 0.7 due to polydextrose dissolution. DSC analysis showed that polydextrose as a gelling agent inhibited the retrogradation of rice starch, which could be used to maintain the quality of cooked rice.

Effects of Extrusion Technology on Physicochemical Properties and Microstructure of Rice Starch Added with Soy Protein Isolate and Whey Protein Isolate.

In order to improve the retrogradation of rice starch (RS) and the quality of rice products, soy protein isolate (SPI), whey protein isolate (WPI), and rice flour were mixed and further extruded into mixed flour. The physicochemical properties and morphology of starch of extruded rice flour (ERS) and starch of extruded mixtures of SPI, WPI, and rice flour (SPI-WPI-ERS) were analyzed. The distribution of amylopectin chain length, molecular weight, microstructure, crystallinity, short-range ordered structure, pasting properties, and thermodynamic properties of RS, ERS, and SPI-WPI-ERS were measured. The results showed that, compared with rice starch, the proportion of long-chain starch, total starch content, and molecular weight were decreased in ERS and SPI-WPI-ERS, but the proportion of short-chain and amylose content was increased. The short-range order structure was destroyed. The water absorption of ERS and SPI-WPI-ERS was much higher than rice starch at 55 °C, 65 °C, and 75 °C, but lower than that of rice starch at 95 °C. Therefore, the retrogradation characteristics of SPI-WPI-ERS were improved. The setback of rice starch products was reduced and the setback of SPI-WPI-ERS was lower than that of ERS. Overall, the retrogradation of rice starch was delayed by adding exogenous protein and extrusion technology, and the application range of rice flour in staple food products was broadened.

Effect of addition of soybean protein isolate on the retrogradation of rice starch

SummaryIn this study, a hybrid system was prepared by mixing rice starch (RS) with different mass fractions (0%–10% dry weight) of soy protein isolate (SPI) to investigate its retrogradation characteristics during storage. The results showed that the addition of SPI led to an increase in pasting temperature and a decrease in setback (SB) and aging rate (P < 0.05). When the level of SPI was increased to 10%, the pasting temperature reached a peak of 75.28°C, resulting in a decrease of 16.52% in regrowth rate and 51.61% in aging rate. The analysis of hardness and secondary structure indicated that the inclusion of SPI resulted in a less robust starch gel structure in comparison to RS, leading to a decrease in gel hardness and the short‐range ordered structure of starch. The pore structure of the starch gel was observed to be smaller and more uniform following the addition of SPI. The presence of SPI hindered the recrystallisation of starch granules, consequently leading to a delay in starch retrogradation. The results of this study have validated the positive effect of incorporating SPI on the anti‐aging properties of starch during storage. This serves as a foundational basis for enhancing the processing attributes of RS and the overall quality of starchy food products.

Effect of Water Content on Rice Starch Gel during Retrogradation

AbstractWater content plays a crucial role in the retrogradation of rice starch. The relationship between the water content of rice starch gels and their structural changes during retrogradation is studied. The results indicate that the gels have three distinct types of water: structural constitution water, starch intermolecular bound water, and free water. The rate of retrogradation increases as the water content increases. Nevertheless, when the water content is lower (1:1) or higher (1:6) than optimal, the starch molecules show limited aggregation and recrystallization, which retards the rate of retrogradation. With the aggregation and recrystallization of starch and the inward contraction of the gel structure, the mobility of water is restricted, and the binding of water to the starch is enhanced. With the sustained contraction of the gel structure, the water‐holding capacity of the gel is weakened. By analyzing the experimental results, water distribution, transformation, and migration in rice starch during retrogradation are delineated. These findings provide a theoretical basis for controlling the retrogradation of rice starch and improving product quality.

Effects of oat β-glucan on the retrogradation behavior of rice starch and its potential mechanism

In this study, to minimize the quality deterioration caused by the retrogradation of starch-based food, the effect and mechanism of oat β-glucan (OG) on the retrogradation of rice starch was investigated. OG effectively decreased storage modulus (G′), syneresis, and retrogradation enthalpy, indicating the inhibition of short-term and long-term retrogradation of rice starch. The competition for water molecules between the OG and rice starch resulted in partial swelling of the starch granules, consequently reducing particle size, lowering amylose leaching, and decreasing the proportion of short-amylose chains. The microstructure characterization showed that the OG-treated rice starch group (ST-OG) exhibited a smoother and denser surface. Particularly, no notable alterations were observed in the structure of the ST-OG sample during storage, owing to the improved water-holding capacity of starch gel and reduced proportion of free water caused by OG. Furthermore, the ordered structure results confirmed the occurrence of hydrogen bonding between OG and rice starch, which hindered the rearrangement of starch molecules. Therefore, OG is an effective natural additive for controlling the retrogradation of starch-based foods.

Effect of the addition of pregelatinized rice starch paste on the retrogradation of rice starch gel

The effect of the addition of pregelatinized rice starch paste (PRSP) on the retrogradation of rice starch (RS) gels was investigated using rheometer, X-ray diffraction (XRD), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and confocal laser scanning microscopy (CLSM). A decrease in the storage modulus of RS gels after short-term storage was found after adding PRSP. The XRD results revealed that the retrogradation degree of RS gels with added PRSP was lower than in the absence of PRSP, suggesting that the addition of PRSP could restrain the long-term retrogradation of rice starch. Moreover, the lower enthalpy changes of RS gels with added PRSP after retrogradation suggested that the progress of amylopectin crystallization was delayed due to PRSP incorporation. SAXS analysis showed that adding PRSP inhibited swelling of RS and decreased the size of aggregation during storage, which suppressed starch retrogradation. In addition, CLSM images indicated that PRSP could form continuous network in which the RS granules embedded, and that gels with PRSP exhibited greater phase separation after 15 d storage. These results suggested that the addition of PRSP inhibited the retrogradation of RS gels. The inhibitory effect is mainly due to PRSP altering the gel formation type and prohibiting the excessive swelling of rice starch granules during gelatinization. This study could provide new insights for the production of rice products and for prolonging their shelf life during storage.

Improving the swelling capacity of granular cold-water rice starch by ultrasound-assisted alcoholic-alkaline treatment

The aim of this study was to determine the ability to improve the capacity of cold swelling and cold-water solubility of rice starch by ultrasonic-assisted alcohol-alkaline and alcohol-alkaline methods. To achieve this, ultrasound powers (U) were varied (30%, 70%, 100%) under the granular cold-water swelling starch (GCWSS) preparation (GCWSS + 30 %U, GCWSS + 70 %U, and GCWSS + 100 %U). The effects of these methods on morphological, pasting properties, amylose content, ratio of 1047/1022 spectra by FTIR, turbidity, freeze–thaw stability, and gel texture were also studied and compared. The results showed that the surface of GCWSS granules presented a honeycomb especially GCWSS + U treatments exhibited more porous on the surface of starch granules. The cold swelling power and solubility of GCWSS + U samples were increased which confirmed by reducing ratio of ordered structure to amorphous structure of starch, and turbidity was also decreased. Moreover, pasting temperature, breakdown, final viscosity, and setback decreased while peak viscosity increased as measured using a Rapid Visco Analyzer. The freeze–thaw stability of GCWSS + U was more resistant to syneresis than GCWSS under repeated freeze–thaw cycles. The reduction of gel hardness and springiness was observed using Texture Analyzer. These changes were enhanced with increasing ultrasound powers. Thus, the results indicate that the different ultrasound-assisted alcohol-alkaline treatments for preparing GCWSS show an effective use in the preparation of GCWSS with improved cold-water swelling and reduced retrogradation of rice starch.

Effect of rice protein on the gelatinization and retrogradation properties of rice starch

In this study, rice starch (RS) was mixed with varying amounts of rice protein (RP; 0 % to 16 %) to explore the effects of protein on the gelatinization and retrogradation of starch during storage. The increased RP addition decreased the viscosity and gelatinization enthalpy of the mixtures but caused an upward trend in the gelatinization temperature, indicating that protein hampers the process of starch gelatinization. Furthermore, RP addition reduced gel hardness, decreased retrogradation enthalpy and crystallization rate constant, but increased Avrami exponent upon RS retrogradation. RP addition also facilitated the mobility of water molecules, weakened the conversion from bound water to free water in the gels, and moderately increased the uniformity and thickness of gel shape. In summary, RP had a dose-dependent effect on the gelatinization and retrogradation behavior of RS, although the anti-retrogradation concentration effect strongly weakened at protein levels exceeding 12 %. It is noteworthy, that excessive RP addition resulted in disulfide bond formation, which increased gel strength and network structure but reduced the ability of RP to facilitate water molecule mobility and restrict water migration, ultimately reducing its anti-retrogradation capability. This phenomenon can be partially attributed to spontaneous protein-protein interaction caused by excessive protein addition, replacing the starch-protein interaction.

Pasting and retrogradation properties of rice starch with phenolics from three varieties of brown rice

SummaryThis work evaluated the influence of phenolics from Black, Indica and Japonica rice bran (2.5–10%) on pasting and retrogradation properties of rice starch. The breakdown, setback, enthalpy values and retrogradation percentage of rice starch were decreased, and the pasting temperature was enhanced with the phenolics from three varieties of brown rice. X‐ray diffraction results suggested that new V‐type crystal at 13.1° was formed and relative crystallinity of rice starch was decreased. The results from fourier transform infrared spectroscopy exhibited that the 1047/1022 cm−1 values of rice starch were decreased with the content increase of phenolics from three varieties of brown rice. The phenolics from three varieties of brown rice resulted in loose surface structure of rice starch. This work may provide evidences for utilisation of phenolics from different varieties of brown rice to improve quality of rice products and inhibit retrogradation of rice starch.

Effect of soluble soybean polysaccharides on the short- and long-term retrogradation properties of instant rice.

Rice starch retrogradation is prone to occur during instant rice storage, which contributes to reduced viscosity, poor sensory characteristics, and shortened shelf life. The purpose of this study was to explore the anti-retrogradation effect of soybean soluble polysaccharides (SSPS) on instant rice and the possible interaction between SSPS and high-moisture starch products. We studied the effects of SSPS on the retrogradation of instant rice, using hardness as an index. The optimal amount of SSPS was 0.2%. Hardness, enthalpy, relative crystallinity, and full width at half maximum values were lower in the SSPS-treated group than in the control group (no SSPS) during storage. The weight loss rate of instant rice had the following trend: SSPS-treated group (0 day) < control group (0 day) < SSPS-treated group (28 days) < control group (28 days). The lower the weight loss rate, the lower was the material loss. Scanning electron microscopy results showed that the gaps between starch granules were less obvious in the control group than in the SSPS-treated group during storage. The SSPS-treated group presented a starch network with uniform chambers. SSPS might compete with starch molecules for water absorption, thereby improving water retention and limiting starch retrogradation. The results showed that adding SSPS to instant rice could effectively inhibit starch retrogradation, because the interaction of SSPS and amylopectin side chains inhibited the crosslinking of starch molecules through hydrogen bonds, which hindered the formation of ordered structures. It was helpful to understand the anti-retrogradation mechanism of SSPS during the storage of instant rice, and provided the basis for the industrial production of high-water-content starch foods. © 2023 Society of Chemical Industry.

Effect of Storage Time and Temperature on Digestibility, Thermal, and Rheological Properties of Retrograded Rice.

Retrogradation is defined as the recrystallization or realignment of amylose and amylopectin chains upon cooling of gelatinization starch gels. The storage conditions such as the storage time and temperature are crucial factors that influence and govern the degree of retrogradation and in turn, affect the formation of resistant starch and alteration of thermal and rheological properties. This article investigates the effect of storage time and temperature on the properties of retrograded rice starch. Rice kernels of five different indigenous varieties, namely Diasang lahi, Khaju lahi, Dhusuri bao, Omkar, and Bili rajamudi were cooked by boiling in water and stored at 4 °C and -20 °C for 6 and 12 h, respectively. Differential scanning calorimetry (DSC) studies revealed in raw form that Bili rajamudi exhibited the highest peak gelatinization temperature (Tp, °C) at 79.05 °C whereas Diasang lahi showed the least Tp at 56.12 °C. Further, it was indicated that the Tp and degree of retrogradation (DR%) also increase with increasing time and decreasing temperature of storage. All samples stored at -20 °C for 12 h exhibited the highest degree of retrogradation DR%. Amongst all five varieties stored at -20 °C for 12 h, Omkar exhibited the highest %DR, followed by Bili rajamudi, Khaju lahi, Dhusuri bao, and Diasang lahi. A negative correlation was also established between Tp and resistant starch content (RS%). It was also observed that the resistant starch (RS%) content increased with the increasing time and decreasing temperature of storage. A strong negative correlation was observed between RS% and non-resistant starch (NRS%). Further, rheological studies indicated that retrogradation also affects the viscosity and dynamic rheological properties of starch. In this study, it was evident that extending storage duration from 6 to 12 h and lowering temperature from 4 to -20 °C impact retrogradation of rice starch, which in turn affects the starch's gelatinization, digestibility, and rheology. Rice starch retrograded at lower temperatures for a longer period could prove to be extremely beneficial for development of food products with better textural properties and high RS content or low glycemic index.

Effects of storage temperatures on the starch digestibility of whole rice with distinct starch fine molecular structure.

Although the retrogradation of rice starch has been extensively investigated, there remain questions as to how storage temperature affects starch inter- and intramolecular interactions in cooked white rice, and the relationship of these interactions with the digestion rate. To this end, micromorphology, crystallinity polymorphisms, molecular interaction patterns and in vitro starch digestibility of 3 rice varieties kept under 5 different storage temperature programs (room temperature (RT), 4 °C, -18 °C, 4 °C/RT (4 °C for 24 h and then RT for 24 h), -18 °C/RT (-18 °C for 24 h and then RT for 24 h)) were investigated. As expected, a significant variance in starch digestibility was observed for samples after storage at different temperatures. Overall, storage at 4 °C could most effectively decrease the starch digestibility of retrograded rice. The digestion rate constant was for the first time found to be determined by short-range amylopectin intermolecular interactions rather than long-range starch molecular interactions, for all different storage conditions. Furthermore, the digestion extent was determined by both inter- and intramolecular interactions among starch molecules as well as by the long-range order of the retrograded double helices. These results could prove useful to devise storage regimes which use retrogradation to produce cooked rice with lower glycemic index.

Effect of high-pressure homogenisation-modified bacterial cellulose on rice starch retrogradation

Delaying rice starch (RS) retrogradation can improve the quality parameters of rice-based starchy foods during storage. Modification of insoluble dietary fibre has always been used in the starchy food industry. Compared with vegetal insoluble dietary fibre, bacterial cellulose (BC) has many advantages such as high purity, smaller particle size, and elevated water absorption capacity. In the present work, BC was modified by high-pressure homogenisation (MBC) with different pressure levels (0, 50, 80, 120, and 160 MPa) to investigate the effect of MBC on RS retrogradation. Results showed that high-pressure homogenisation could decrease the particle size of BC. MBC addition to RS decreased paste breakdown and setback, thus suggesting that MBC might be a good candidate for increasing the stability of RS paste, and inhibiting its short-term retrogradation. The thermal properties and X-ray diffraction patterns of RS indicated that supplementing MBC could decrease the gelatinised enthalpy and relative crystallinity of RS paste during storage. Results also indicated that MBC could provide an opportunity to restrain RS retrogradation, and might be suitable for designing fibre-enriched products.

Effects of Oligomeric Procyanidins From Lotus Seedpod on the Retrogradation Properties of Rice Starch.

The extent of retrogradation strongly affects certain physical and cooking properties of rice starch (RS), which are important to consumers. In this study, oligomeric procyanidins from lotus seedpod (LSOPC) was prepared and used to investigate its inhibitory effect on RS retrogradation. Various structural changes of RS during retrogradation were characterized by differential scanning calorimetry, low field nuclear magnetic resonance, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The results showed LSOPC could effectively retard both short- and long-term retrogradation of RS, and its inhibitory effect was dependent on the administered concentration of LSOPC. Molecule simulation revealed the interactions of RS and LSOPC, which indicated that the competition of hydrogen bonds between RS and LSOPC was the critical factor for anti-retrogradation. This inhibitory effect and mechanism of action of LSOPC could promote its applications in the field of starch anti-retrogradation.

Lysine Bioavailability in School-Age Children Consuming Rice Is Reduced by Starch Retrogradation

Rice is one of the most commonly consumed cereal grains and is part of staple diets in the majority of the world. However, it is regarded as an incomplete protein, with lysine being a limiting amino acid. Our objectives were to determine the bioavailability of lysine in school-age children consuming cooked white rice and to assess the effect of rice starch retrogradation. Bioavailability or metabolic availability (MA) of lysine was determined using the indicator amino acid oxidation (IAAO) method in a repeated-measures design. Six healthy school-age children (3 boys, 3 girls) with a mean±SD age of 6.8±0.98y randomly received 4 crystalline l-lysine intakes (2, 6, 10, 14 mg · kg-1 · d-1), and 5 rice intakes to provide lysine at 8, 11, or 14 mg · kg-1 · d-1. The 14 mg · kg-1 · d-1 intakes were measured twice as warm rice and once as cold rice (to assess the impact of starch retrogradation on MA). Diets provided protein at 1.5 g · kg-1 · d-1 and calories at 1.7 times the participant's measured resting energy requirement, and were isonitrogenous. Breath samples were collected at baseline and during an isotopic steady state for 13C enrichment measurement. The MA of lysine from rice was determined by comparing the IAAO response of rice with l-lysine using the slope-ratio and single intake methods. Starch retrogradation was characterized using differential scanning calorimetry. MA of lysine in warm rice measured in school-age children was 97.5% and was similar to a repeated rice study (97.1%) within the same study population. MA of lysine was reduced significantly (P<0.05) to 86.1% when the cooked rice was consumed cold, which corresponded to detectable starch retrogradation. To our knowledge, this is the first study to measure the MA of lysine from rice in school-age children. Although the bioavailability of lysine from rice is high, it can be reduced by retrogradation of its starch component.This trial was registered at clinicaltrials.gov as NCT04135040.

Investigating the potential of slow-retrograding starches to reduce staling in soft savory bread and sweet cake model systems

The potential anti-staling property of starches with slow-retrograding amylopectin was studied in soft wheat bread and cake model systems. Normal rice, waxy rice, and wheat starches were processed by drum drying or extrusion, and native starch was used as a comparator. Extrusion processing causing amylopectin fragmentation can reduce intermolecular retrogradation of rice starch. Starches were incorporated into model breads and cakes as partial replacements for flour on a dry weight basis (3 and 6% for cakes, 5 and 15% for breads). Starches pregelatinized by extrusion had moderate molecular fragmentation, as indicated by RVA and HPSEC-MALLS-RI. Starches previously shown to have lower intermolecular retrograding amylopectin (normal rice, waxy rice) resulted in minor to moderate reductions in hardness and other textural properties as indicated by texture profile analysis (TPA) in breads and cakes upon storage for up to 12 wk. A higher degree of starch fragmentation is suggested to produce lower staling. Incorporation of normal and waxy rice starches resulted in softer breads and cakes than wheat starch, which could be attributed to the shorter external and internal amylopectin chains of rice starch. Higher inclusion (15%) of slow-retrograding waxy rice in the bread model system showed the most potential for anti-staling property.

Annealing treatment of amylose and amylopectin extracted from rice starch

Annealing behavior of amylose and amylopectin was unclear. In this work, high purity amylose and amylopectin were extracted from rice starch, and structural properties of the retrograded rice starch, amylose, and amylopectin before and after annealing treatment were explored. It was found that the purity of the amylose and amylopectin was 95.64% ± 2.69% and 94.98% ± 0.97%, respectively. Their molecular weight was (2.93 ± 0.21) × 106 Da and (5.90 ± 0.13) × 107 Da, respectively. Besides, the relative crystallinities and ratios of 1047 cm−1/1022 cm−1 of the retrograded rice starch and amylose were significantly increased by annealing treatment, while that of retrograded amylopectin did not change. These results clarified that amylose was more sensitive to annealing treatment than amylopectin, and amylose was more responsible for annealing of starch than amylopectin. The findings contributed to a better understanding of the annealing behavior of starch.

Effects of amylose and amylopectin chain-length distribution on the kinetics of long-term rice starch retrogradation

Understanding the characteristics of long-term starch retrogradation is critical for developing functional foods with desirable textural attributes. The long-term retrogradation kinetics of 10 different rice starches with a wide range of amylose content were thus investigated in this study, focusing on their relations with the starch chain-length distributions (CLDs). Correlation analysis between the retrogradation parameters from differential scanning calorimetry (DSC) with starch CLDs showed for the first time that the amylose content had a parabolic relationship with the melting conclusion temperature and enthalpy of long-term retrograded starches, indicating that the amylose component has a bi-directional effect on the long-term amylopectin retrogradation property. Furthermore, the amount of amylose short-medium chains and amylopectin medium chains were negatively and positively correlated with the melting onset temperature of long-term retrograded starches, respectively. The information learnt from this study could be applied in the rice industry to improve the textural attributes of cooked rice.