Physicochemical Properties Of Rice Starch Research Articles

Understanding the Relationship between the Molecular Structure and Physicochemical Properties of Soft Rice Starch.

The relationship between the molecular structure and physicochemical properties of soft rice starch (SRS) has been investigated in this research. The amylose content of SRS ranged from 10.76% to 11.85%, classified as the very low amylose type. Compared to waxy and japonica rice starch, the largest amount of small starch granules and the highest viscosity were shown in the SRS. The results of X-ray diffraction and Fourier transform infrared proved that the SRS depicted a typical A-type pattern with a low short-range ordered structure. Additionally, SRS had a great deal of A and B1 chains. Molecular weights and density of starch from soft rice were lower than those from waxy rice but higher than those from japonica rice. Furthermore, SRS possessed a higher amount of resistant starch. Correlation analysis indicated that the amylose content and the chain-length distributions of amylopectin play a major role in influencing the molecular structure and physicochemical properties of rice starch. In conclusion, the low amylose content, highest viscosity, and other excellent properties of soft rice starch make it have bright application prospects in instant rice and rice cakes.

Effects of nitrogen application on physicochemical properties of rice starch under elevated temperature

Nitrogen fertilization can mitigate the negative effects of high temperatures on rice. In this study, we simulated dynamic field temperature increases using a free-air temperature enhancement system. Changes in the physicochemical properties of starch were investigated under increasing nitrogen fertilization during the grain-filling stage. We observed that the application of nitrogen at elevated temperatures (ETN) did not change the chain length distribution compared with elevated temperatures (ET) alone; however, it did significantly increase the heights of the first and second amylose peaks. Specifically, ETN significantly decreased the height of fifth amylopectin and relative crystallinity, and the changes it introduced in the physicochemical properties of starch were greater than those of ET. Overall, these changes in starch properties may be associated with the ability of nitrogen to facilitate the maintenance of rice quality at high temperatures.

Complexation between rice starch and cellulose nanocrystal from black tea residues: Gelatinization properties and digestibility in vitro

In this work, cellulose nanocrystal (CNC) was extracted from black tea waste and its effects on the physicochemical properties of rice starch were explored. It was revealed that CNC improved the viscosity of starch during pasting and inhibited its short-term retrogradation. The addition of CNC changed the gelatinization enthalpy and improved the shear resistance, viscoelasticity, and short-range ordering of starch paste, which meant that CNC made the starch paste system more stable. The interaction of CNC with starch was analyzed using quantum chemistry methods, and it was demonstrated that the hydrogen bonds were formed between starch molecules and the hydroxyl groups of CNC. In addition, the digestibility of starch gels containing CNC was significantly decreased because CNC could dissociate and act as an inhibitor of amylase. This study further expanded the understanding of the interactions between CNC and starch during processing, which could provide a reference for the application of CNC in starch-based foods and the development of functional foods with a low glycemic index.

Variation of rice starch structure and physicochemical properties in response to high natural temperature during the reproductive stage.

Climate warming affects rice growth at different phenological stages, thereby increasing rice chalkiness and protein content and reducing eating and cooking quality (ECQ). The structural and physicochemical properties of rice starch played important roles in determining rice quality. However, differences in their response to high temperature during the reproductive stage have been rarely studied. In the present study, they were evaluated and compared between two contrasting natural temperature field conditions, namely, high seasonal temperature (HST) and low seasonal temperature (LST), during the reproductive stage of rice in 2017 and 2018. Compared with LST, HST significantly deteriorated rice quality, including increased grain chalkiness, setback, consistence, and pasting temperature and reduced taste values. HST considerably reduced the total starch and increased the protein content. Likewise, HST significantly reduced the short amylopectin chains [degree of polymerization (DP) <12] and increased the long amylopectin chains (DP > 12) and relative crystallinity. The starch structure, total starch content, and protein content explained 91.4%, 90.4%, and 89.2% of the total variations in pasting properties, taste value, and grain chalkiness degree, respectively. In conclusion, we suggested that rice quality variations were closely associated with the changes in chemical composition content (total starch and protein content) and starch structure in response to HST. These results indicated that we should improve the resistance of rice to high temperature during the reproductive stage to improve the fine structure of rice starch in further breeding and practice.

The Influence of Temperature Changes on the Rice Starch Structure and Digestive Characteristics: One and Two-Step Annealing.

This study investigated the effects of annealing on the structural and physicochemical properties of rice starch below the onset temperature (To) by 5 °C and 15 °C. The results revealed that annealing improved the gelatinization temperature of rice starch, decreased the swelling power, solubility, and paste viscosity of rice starch, and had no significant effects on the morphological structure and crystal configuration of rice starch. In one-step annealing, the annealing temperature of 60 °C is more conducive to the rearrangement of starch molecules, so its crystallinity, short-range ordered structure, and gelatinization temperature are higher than at 50 °C; however, its RDS, SDS, and RS contents will be increased. During the two-step annealing treatment, the temperature change is not conducive to the molecular chain rearrangement and to the formation of perfect crystalline structure, which increases the sensitivity of enzymes to starch, so the RDS content of starch increases significantly, while the RS content decreases.

Changes in physicochemical properties and structural characteristics of rice starch during extrusion processing: The role of glutelin and different extrusion zones

This study aimed to investigate the effects of glutelin on the structural and physicochemical properties of rice starch in different extrusion zones. The addition of glutelin inhibited the swelling of starch granules in the melting zone while induced the aggregation of starch in the die and extrudate. The results of differential scanning calorimetry and X-ray diffraction confirmed that starch granules were completely gelatinized in the melting zone and the incorporation of glutelin did not change its crystalline pattern. The presence of glutelin slightly increased the short-range order of rice starch while decreasing its iodine-binding capacity and branching degree, whereas no covalent bond was formed between them. In summary, the strong thermo-mechanical and heat-moisture effect of the melting zone promoted the interaction of glutelin and starch, the addition of glutelin had a more obvious effect on the structural properties of starch in this zone, die and extrudate.

Radio frequency energy regulates the multi-scale structure, digestive and physicochemical properties of rice starch

Radio frequency (RF) heating as an emerging technology was applied to regulate the structural, digestive and physicochemical properties of rice starch. In vitro digestibility results showed that RF treatment enhanced the resistant starch content and reduced the rapidly digestible starch content of rice starch, resulting in higher resistant to enzyme hydrolysis. Microstructure analysis indicated that RF treatment caused the granular surface erosions and morphology changes with increasing treatment time. RF treatment did not alter the A-type crystal form of starch, but disrupted the relative crystallinity, short-range molecular order, and lamellar structure in different degrees. Moreover, the DSC results suggested that starch orders with a higher thermal stability formed after RF treatment, thereby reducing the accessibility of starch granules to the enzyme. Furthermore, rapid viscosity analysis revealed that RF treatment significantly reduced the peak viscosity and breakdown of indica and japonica rice starch, while increased them in waxy rice starch. The rheological properties of rice starch were also changed after RF treatment. This work provides a theoretical basis for the application of RF technology in starch modification.

Effects of Liquid Nitrogen Deep Freezing Treatment on Rice Starch Properties

AbstractRice is the most important food crop in Thailand but has low value as commercial uses of rice are limited. Changes in rice starch after deep freezing with liquid nitrogen are studied. Results show that deep freezing affects the physicochemical properties of rice starch depending on amylose and moisture contents. Deep freezing cause alterations in particle size, swelling power, and acid hydrolysis. Pasting properties analyzed by a rapid visco analyzer (RVA) indicate that after freezing, samples are more stable to shear than native rice. Thermal properties determine by differential scanning calorimetry show that gelatinization enthalpy is lower in deep frozen samples. Scanning electron microscopy shows that starch granules are affected by deep freezing, while the sample surface exhibits merging between granules that contain large amounts of water.

Yield, Grain Quality, and Starch Physicochemical Properties of 2 Elite Thai Rice Cultivars Grown under Varying Production Systems and Soil Characteristics.

Rice production systems and soil characteristics play a crucial role in determining its yield and grain quality. Two elite Thai rice cultivars, namely, KDML105 and RD6, were cultivated in two production systems with distinct soil characteristics, including net-house pot production and open-field production. Under open-field system, KDML105 and RD6 had greater panicle number, total grain weight, 100-grain weight, grain size, and dimension than those grown in the net-house. The amounts of reducing sugar and long amylopectin branch chains (DP 25–36) of the RD6 grains along with the amounts of long branch chains (DP 25–36 and DP ≥ 37), C-type starch granules, and average chain length of the KDML105 were substantially enhanced by the open-field cultivation. Contrastingly, the relative crystallinity of RD6 starch and the amounts of short branch chains (DP 6–12 and DP 13–24), B- and A-type granules, and median granule size of KDML105 starch were significantly suppressed. Consequently, the open-field-grown RD6 starch displayed significant changes in its gelatinization and retrogradation properties, whereas, certain retrogradation parameters and peak viscosity (PV) of KDML105 starches were differentially affected by the distinct cultivating conditions. This study demonstrated the influences of production systems and soil characteristics on the physicochemical properties of rice starches.

Impact of long-term storage on multi-scale structures and physicochemical properties of starch isolated from rice grains

Rice short-term (less than 12 months) storage significantly affected starch structures and physicochemical properties, and in turn, influenced rice functionalities. However, effects of rice long-term (more than 12 months) storage on starch structures and functionalities have been not resolved yet. This study revealed the changes in structures and physicochemical properties of starch during rice long-term storage (12–36 months). Rice storage resulted in degradation of starch molecules, which increased amylose content and reduced the content of long branch-chains of amylopectin, double helices, short-range ordered structures, crystalline structures, and lamellar ordering degree along with apparent erosion of starch granules. Those structural changes significantly increased starch thermostability, favored starch short-term reassociation, and promoted starch enzymatic digestion. Comparing with the short-term storage (1 year of storage), the long-term storage (2 or 3 years of storage) yielded a more serious degradation on starch multi-scale structures, and in turn, resulted in a higher thermostability, and better-defined gel structures and higher starch digestion extent after cooking and cooling. Compared with the short-term aged rice, the long-term aged rice is a better candidate to prepare rice-based gel-like foods such as noodles. This study provided a promising pathway to control structures and physicochemical properties of rice starch and even rice-based foods via simply controlling rice-storage time.

Effect of vacuum combined ultrasound treatment on the fine structure and physiochemical properties of rice starch

This study aimed to investigate the effect of vacuum combined ultrasound treatment on the fine structure and the physicochemical properties of rice starch. Rice starch was treated with vacuum (0.09 MPa) and ultrasound (300 W) in different ways, separately or jointly. The granular morphology, particle size distribution, lamellar architecture, chain length distribution, crystal structure, thermal property and gelatinization property of starch were analyzed. The results showed that vacuum combined ultrasound treatment could result in severe shrinkage and damage of starch granules. Examination of starch structure revealed a reduced average particle size with narrowed distribution range, decreased ordering degree of lamellar architecture and shortened chain length of rice starch after vacuum combined ultrasound treatment. Although vacuum combined ultrasound treatment had no effects on crystal type and functional chemical groups of rice starch, it reduced the relative crystallinity. Physiochemical investigation suggested that vacuum combined ultrasound treatment altered the thermal and gelatinization properties of rice flour by reducing the gelatinization enthalpy and gelatinization temperature. Our results suggested that vacuum combined ultrasound treatment affected the fine structure of rice starch and subsequently altered the physiochemical properties of rice flour.

Investigation of structural and physico-chemical properties of rice starch with varied amylose content: A combined microscopy, spectroscopy, and thermal study

Starch from a given botanical source can vary considerably in terms of physicochemical properties in its native and hydrolyzed forms. The current study investigated the structural and functional characteristics of starch from ten indigenous rice varieties endemic to Northeast India. In vitro enzymatic hydrolysis was used to reveal the dextrose equivalent profile of each type of starch. Gezep Sali and Betguti Sali respectively exhibited the highest and lowest starch hydrolysis. Among the ten rice varieties, amylose content varied between 7.50 and 28.58%. Optical and scanning electron microscopy (SEM) revealed the polyhedral shape of the native starch granules and deformation of the shape upon enzymatic hydrolysis. Second harmonic generation (SHG) microscopy and X-ray diffraction (XRD) analysis confirmed the presence of and variations in starch crystallinity. XRD revealed spectral peaks characteristic of A-type starch crystals in the native form. The elevated intensity of XRD peaks in hydrolyzed starch granules confirmed the occurrence of amylose hydrolysis rather than hydrolysis in amylopectin regions. Fourier transform infrared (FTIR) spectra revealed the common stretching and bending of bonds in all native starches; however, changes were observed in the fingerprint region (1080, 1000, 926 cm−1) of hydrolyzed starch granules, which indicates the amylolysis of the amylose region and disturbances in the ordered arrangement in the crystalline part. Differential scanning calorimeter (DSC) endotherms revealed the highest and lowest gelatinization peak temperatures in Harfoni (78 °C) and Tulosi Sali (41 °C) rice cultivars, respectively. The findings in this study can help to optimize the usage of rice starch in food and non-food industries. Furthermore, understanding the control points of starch digestion and genetically tailoring rice grains with different digestibility could be beneficial for nutraceutical applications.

The role of indica starch in the mechanism of formation of fresh rice noodles

Starch is the largest component in frequently consumed fresh rice noodles (FRN). The effects of morphology, relative crystallinity, molecular weight distribution and physicochemical (rheological, water hydration and gel texture) properties of starch from five rice cultivars with different amylose contents on the formation of FRN were investigated. FRN made from NR rice cultivar, used for commercial rice noodles making, showed excellent FRN texture. NR starch exhibited larger G′ and smaller tan δ values. The morphology of FRN from GM03 cultivar was closest to NR, but had higher hardness and lower springiness, resilience and cohesiveness. Its starch granules morphology was relatively small and round. The extracted starch from Zhongzao 35, Zao 87 and BX02 rice cultivars, with higher swelling power or lower proportions of amylose (FrI) and higher proportions of amylopectin (FrII), could not produce a dense and consistent FRN structure. It was observed that relative crystallinity of the starch samples had no influence on the formation of FRN. Nevertheless, the gel texture of starch played a role in the formation of FRN. The formation of FRN is the common effect of structure and physicochemical properties of rice starch. The finding of this research would be useful in understanding the role of starch in producing FRN of high quality.

Effects of glutelin and lipid oxidation on the physicochemical properties of rice starch

AbstractBackground and objectivesStarch properties are closely related to the rice quality as starch interacts with other components during rice storage. However, several studies have neglected that the changes in proteins and lipids influence the properties of starch in rice. Herein, we used an artificial climate chest to characterize the effect of glutelin and lipid oxidation on the physicochemical properties of starch during rice storage.FindingsOxidation occurs in glutelin and lipids during the rice storage stage (p &lt; .01). The oxidation indexes of glutelin and lipids showed the same significant negative correlation in peak viscosity (PV), breakdown (BD), and setback (SB). In contrast, concerning amylose content, final viscosity (FV), and SB, the oxidation of glutelin rather than lipids was more closely related to the changes observed in starch properties (p &lt; .01). Lipid oxidation significantly correlated with trough viscosity (TV) and amylopectin content than glutelin oxidation (p &lt; .01).ConclusionsAll the oxidation indicators of glutelin and lipids were inversely correlated with BD and SB (p &lt; .01). Carbonyl compound content and fatty acid oxidation were significantly correlated with the physicochemical properties of rice starch.Significance and noveltyThe physicochemical changes in starch are closely related to the oxidation of glutelin and lipids, which can be used as indicators for assessing rice quality.

Structural changes of rice starch and activity inhibition of starch digestive enzymes by anthocyanins retarded starch digestibility

The effects of anthocyanins on in vitro and in vivo digestibility of rice starch were evaluated in this study. Then, the effects of anthocyanins on physicochemical properties of rice starch and on starch digestive enzymes (α-amylase and α-glucosidase) were investigated to understand the mechanism of the effects of anthocyanins on starch digestibility. Characterization of physicochemical properties of rice starch indicates a structural change due to the presence of anthocyanins, hindering its access to starch digestive enzymes. Besides, anthocyanins inhibited the activities of starch digestive enzymes by binding to their active sites, competing with the substrates and changing the secondary structure of the enzymes. The above stated changes of rice starch and starch digestive enzymes due to the presence of anthocyanins both contributed to retarding the digestibility of rice starch. This study could offer some theoretical guidance to the development of new type rice-based food with low glycemic index.

Radio Frequency Energy Regulates the Multi-Scale Structure, Digestive and Physicochemical Properties of Rice Starch

Radio Frequency Energy Regulates the Multi-Scale Structure, Digestive and Physicochemical Properties of Rice Starch

Influence of moisture and amylose on the physicochemical properties of rice starch during heat treatment

Moisture and amylose are important factors affecting the quality of heat-treated starches. The amylose content in heat-treated rice starch increased as moisture content (MC) increased from 8% to 30%, but decreased at MC of 70%. With the increase of MC, the paste transmittance, gelatinization temperature, and digestibility of starch increased, whereas the swelling power and enthalpy decreased. The long- and short-range molecular order and the digestive properties of starch with MC ≤ 30% changed moderately, but high MC (70%) gelatinized the starch and drastically changed the physicochemical properties. High amylose content in rice starch led to low long- and short-range molecular order, swelling power, and gelatinization temperature, but increased resistant starch. The results indicated that 30% of MC separates effects of heat treatment of starch, where low MC (≤30%) and high amylose lowers digestibility, which is beneficial for diabetics, while high MC (>30%) promotes solubility and transparency.

Electron beam irradiation as a tool for rice grain storage and its effects on the physicochemical properties of rice starch

In this study, rice grains were treated with electron beam irradiation (EBI). The storage properties of the irradiated rice, as well as the physicochemical properties of isolated starches, were studied. As irradiation dose was increased from 0 kGy to 10 kGy, the lipase activity of irradiated rice decreased from 7.82 mg KOH/100 g to 5.15 mg KOH/100 g. EBI treatment did not significantly (p < 0.05) change fatty acid values. The granular structure of the isolated starches was partially destroyed after severe irradiation, and EBI treatment also caused the degradation of the molecular structures of amylopectin and amylose. All of the starches with or without EBI treatment displayed A-type crystalline structures, and 10 kGy of irradiation disrupted double-helical structures and subsequently decreased relative crystallinity. The formation of carboxyl groups reduced the digestibility of the starches, whereas the disruption of crystallites allowed digestive enzymes to access degraded starch chains easily. Overall, results demonstrated that a low dose of irradiation had insignificant effects on the quality of rice grains and corresponding starches. Thus, EBI could be a green and safe strategy for rice storage.

Morphological and physicochemical properties of rice starch dry heated with whey protein isolate

The effect of dry heating treatment with whey protein isolate (WPI) on the morphological and physicochemical properties of rice starch (RS) was investigated. Scanning electron microscopy results demonstrated that WPI-mediated aggregation of RS granules was more pronounced as the dry heating time increased, which was further confirmed by analysis of the particle size distribution. Differential scanning calorimetry results showed that dry heating treatment in the presence of WPI significantly decreased the gelatinization temperature of RS but without affecting the gelatinization enthalpy change. X-ray diffraction and Fourier transform infrared spectroscopy analysis demonstrated that the long and short range orders of RS were partially damaged following dry heating treatment and the incorporation of WPI. In addition, a significant increase in the oil-binding ability was observed in the dry heated starch samples, which was more pronounced under the combination of dry heating with WPI. These phenomena could be attributed to the interaction of RS with WPI, the aggregation and denaturation of WPI, and the disruption of hydrogen bonds within starch during the treatment process.

Effects of nitrogen fertilizer on structure and physicochemical properties of ‘super’ rice starch

Nitrogen fertilizer is an essential nutrient for rice (Oryza sativa L.), especially, for newly bred ‘super’ rice cultivars with great yield potential. The effects of nitrogen fertilizer (0, 100, 200, 300, 400 kg N ha−1) on the physicochemical properties of two high yielding ‘super’ rice Yongyou 2640 and Lianjing 7 were investigated in this study. The application of nitrogen fertilizer affects the structure of rice starch, thus changing its functional properties, which ultimately leads to a change in the quality of both rice cultivars. There were dose effects of nitrogen fertilizer on grain quality. Grain quality was improved under moderate nitrogen inputs (100 & 200 kg N ha−1), but deteriorated at excessive nitrogen levels (300 & 400 kg N ha−1). With moderate N application, starch granule size increased and the surface of starch granule became smoother; there were higher proportion of short branch-chain of amylopectin and lower proportion of long branch-chain of amylopectin with low relative crystallinity, lower degree of order of structure and higher content of amorphous structure at the outer region of the starch granules; peak viscosity, hot viscosity, breakdown value were increased while setback and pasting temperature were decreased; gelatinization temperature, gelatinization enthalpy, retrogradation enthalpy, retrogradation percentage, hardness were decreased while viscosity were increased. At excessive nitrogen inputs, the grain quality was deteriorated and the opposite results of structure and physicochemical properties of rice starch were observed. These results indicate that nitrogen fertilizer significantly affected the structure and physicochemical properties of rice starch, and appropriate fertilization would improve rice grain quality.