Rice Starch Particles Research Articles

Effects of Qingke β-glucan with different molecular weights on pasting, gelation, and digestive properties of rice starch.

This study aimed to investigate the impact of Qingke β-glucan (QBG) concentrations and molecular weights (MWs) on rice starch (RS). With the increasing concentrations and MWs, the pasting properties and gelatinization enthalpy of RS/QBG suspension decreasing was observed by using rheometer and differential thermal scanning analysis, respectively, which was consistent with the results of X-ray diffraction. In Infrared spectrum, QBG combined with leached amylose via hydrogen bonds, thus preventing the reaggregation of RS particles and inhibiting the short-term retrogradation of RS. The results of scanning electron microscopy and confocal laser scanning microscopy suggested that interaction between QBG and RS changed RS microstructure, reduced the leached amylose of the starch, and thus altered RS/QBG digestibility that the digestion rate of RS/QBG decreased with the incrementing QBG MWs at in vitro simulated experiments. These results provide further understanding and expand potential application to starch-based foods.

Emulsion-based oleogelation using octenyl succinic anhydride modified granular cold-water swelling starch

Oleogels were produced starting from Pickering emulsions, stabilized by octenyl succinic anhydride (OSA) modified high amylose (HS-OSA), waxy (WS-OSA), and granular cold-water swelling starch (GCWS-OSA). GCWS-OSA had the highest degree of OSA substitution (DS) and contact angle with the oil-water interface, and the smallest emulsion droplet size (0.0149, 80.4°, 12.58 μm), followed by WS-OSA (0.0098, 76.2°, 22.83 μm) and HS-OSA (0.0049, 73.3°, 31.50 μm). In small amplitude oscillatory shear (SAOS), all template emulsions and oleogels had G’ > G’’ (tan δ ≤ 0.1) and behaved as soft viscoelastic solids. The highest G’ was observed for WS-OSA and GCWS-OSA, which clearly produced a much stiffer material. In large amplitude oscillatory shear (LAOS), WS-OSA and GCWS-OSA oleogels showed a progressive disruption of the microstructure, which resulted in an increase in viscous dissipation. At the highest strain of 20.5%, WS-OSA and GCWS-OSA were showing completely plastic behavior, whereas the structure of the HS-OSA based oleogel still displayed significant residual elasticity, indicating only partial disruption of the microstructure. WS-OSA and GCWS-OSA also had a much higher strain overshoot (Payne effect) in G”, then the sample based on HS-OSA. The higher DS and granular structure of GCWS-OSA contributed to a more stable Pickering emulsion and stiffer oleogel. • Pickering emulsions were used as a template to create oleogels. • Emulsions were stabilized using three types of OSA-modified rice starch particles. • Emulsions and oleogels were characterized using SAOS and LAOS measurements. • The Pickering emulsions produced oleogels with high stiffness. • The stiffness of oleogels can be tailored by choice of the appropriate starch.

Cationic oxidized microporous rice starch: Preparation, characterization, and properties.

The combination of enzymolysis of compound enzyme, oxidation of sodium hypochlorite, and cationic etherification of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMA) was selected for the functionalization of rice starch (RS) to better raise the performances. The results showed that the oxidation and etherification could improve the acid and alkali resistance of RS, and enhanced its thermal stability. The crystalline structure of RS was an A-type, the enzymolysis, oxidation, and etherification did not change the structural type, while the crystallinity degree of RS derivatives was all reduced. The enzymolysis, oxidation, and etherification altered the pasting properties of RS, and could effectively decrease the setback and breakdown of RS. The oxidation of sodium hypochlorite not only damaged RS particles containing no micropores, but also destroyed the particles containing the micropores. The enzymolysis and oxidation more seriously destroyed the crystalline region than cationic etherification. The oxidation could increase the enthalpy change of RS, whereas the enzymolysis and etherification decreased its enthalpy change. In addition, the enzymolysis and oxidation could lead to the evident increase in average size of RS. The cationic etherification was able to improve the adsorption of Cu2+ on RS, whereas the low oxidation could only slightly ameliorate the adsorption of Cu2+ . PRACTICAL APPLICATION: Cationic oxidized microporous rice starch as an adsorbent, slow-release agent, and flocculant will be well used in food, medicine, pesticide, papermaking, waste water treatment, and so on owing to its abundant micropores, anionic groups, and cationic groups as well as small particle size and narrow size range.

Comparative study of Pickering emulsions stabilised by starch particles from different botanical origins

SummaryStarch botanical origin is a key factor for the characteristics of Pickering emulsion. Starches with different sizes from rice (2.9–7.6 µm), waxy corn (9.3–25.0 µm), wheat (11.4–33.7 µm) and potato (24.4–54.1 µm) were esterified by octenyl succinic anhydride. The modified starch particles were used as stabilisers to produce oil‐in‐water Pickering emulsions. The physical stability, microstructures and rheological properties of different emulsions were compared. Results indicated that the emulsion stabilised with rice starch particles had the minimum droplet size of 83.6 µm and best physical stability during 30 days of storage. Moreover, starch particle size was negatively correlated with emulsion stability (P < 0.05). The particles (3.85% of the emulsion, w/w) built up wall‐like structures around oil droplets, which prevented them from freely moving. All emulsions showed pseudoplastic fluid behaviours and presented gel properties, but elastic modulus (G′) and loss modulus (G″) were mainly affected by starch botanical origins.

Nano/Submicrometer Milled Red Rice Particles-Stabilized Pickering Emulsions and Their Antioxidative Properties.

Nano/submicrometer red rice particles were obtained through processing a type of red rice using media-milling. The diameters of red rice were gradually reduced as processing time increased. After 4 h of processing, the particle size of milled red rice was reduced to around 692 nm. Microscopic observation and SEM analysis confirmed the presence of nano/submicrometer particles. The phytochemical contents of milled red rice were analyzed. The total anthocyanin content of red rice increased after milling process. Its phenolic and flavonoid contents were slightly decreased after the milling process. All milled red rice exhibited good ferric reducing antioxidant property (FRAP) and DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The emulsifying ability of milled red rice particles with different milling time was characterized. Milled red rice starch particles with a concentration of 0.8-3.5% were able to form stable Pickering emulsions, and milled red rice particles retarded the oil oxidation process when being used as Pickering emulsions stabilizers. This pioneer study directly modifies whole grain materials to submicrometer particles that can form stable food grade Pickering emulsions with intrinsic antioxidant properties.

Separation performance of an 8 mm mini-hydrocyclone and its application to the treatment of rice starch wastewater

ABSTRACTThe rice starch particles are difficult to separate from starch suspensions for its fine diameter. In this work, an 8 mm mini-hydrocyclone is designed, and its separation performance and potential for the treatment of rice starch wastewater is investigated. The capacities, total separation efficiencies of an 8 mm mini-hydrocyclone and a 10 mm mini-hydrocyclone are compared. The experimental results reveal that the total separation efficiency of the 8 mm mini-hydrocyclone is approximately 13% higher than that of the 10 mm mini-hydrocyclone. A total separation efficiency of 92.1% was obtained using a two-stage hydrocyclone separation process comprising two 8 mm mini-hydrocyclones connected in series. The research findings can be utilized to efficiently treat the rice starch wastewater.

Rice Starch Particle Interactions at Air/Aqueous Interfaces-Effect of Particle Hydrophobicity and Solution Ionic Strength.

Starch particles modified by esterification with dicarboxylic acids to give octenyl succinic anhydride (OSA) starch is an approved food additive that can be used to stabilize oil in water emulsions used in foods and drinks. However, the effects of the OSA modification of the starch particle on the interfacial interactions are not fully understood. Here, we directly measured the packing of films of rice starch granules, i.e., the natural particle found inside the plant, at air/aqueous interfaces, and the interaction forces in that system as a function of the particle hydrophobicity and ionic strength, in order to gain insight on how starch particles can stabilize emulsions. This was achieved by using a combined Langmuir trough and optical microscope system, and the Monolayer Interaction Particle Apparatus. Native rice starch particles were seen to form large aggregates at air/water interfaces, causing films with large voids to be formed at the interface. The OSA modification of the rice starches particles decreased this aggregation. Increasing the degree of modification improved the particle packing within the film of particles at the air/water interface, due to the introduction of inter-particle electrostatic interactions within the film. The introduction of salt to the water phase caused the particles to aggregate and form holes within the film, due to the screening of the charged groups on the starch particles by the salt. The presence of these holes in the film decreased the stiffness of the films. The effect of the OSA modification was concluded to decrease the aggregation of the particles at an air/water interface. The presence of salts, however, caused the particles to aggregate, thereby reducing the strength of the interfacial film.

Acetylated debranched rice starch: Structure, characterization, and functional properties

ABSTRACTCombining biological and chemical methods for the modification of starch is a very interesting prospect. The goal of this work was to investigate the influence of debranching and acetylation on the structure of rice starch (RS), ultimately to improve the function of RS. Our experimental results showed that RS particles can be completely destroyed by debranching. The crystal structure of RS is A-type, but the structure of debranched rice starch (DRS) and acetylated debranched rice starch (ADRS) is B-type. The crystallinity degree of DRS and ADRS was less than that of RS. The surface of DRS and ADRS particles became very rough, marking a complete departure from the surface of smooth RS granules. Acetylation occurred specifically at the sides of DRS granules. The surface hydroxyl numbers of RS increased after debranching and acetylation, and the thermal characteristics changed substantially. Debranching led to an increase in onset temperature from 97.79 to 107.64°C; acetylation improved the freeze-thaw stability and swelling power of both the RS and DRS. The blue value of RS varied from 0.424 to 0.640 due to debranching.

Tribological properties of rice starch in liquid and semi-solid food model systems

This study investigated the tribological and rheological properties of liquid and semi-solid food model systems containing micro-granular rice starch. Native (uncooked) and gelatinized rice starch dispersions, o/w emulsions and emulsion-filled gelatin gels were studied as food model systems. Native rice starch particles behaved as active fillers and increased the gel modulus with increasing concentration. At low concentration, soft gelatinized rice starch particles decreased gel modulus. At high concentration, gelatinized rice starch increased the gel modulus due to dense packing of particles. Native and gelatinized rice starch increased friction coefficients with increasing concentration due to different mechanisms. Native rice starch particles increase friction probably due to their irregular shape and particle agglomerations (at high concentration) that indirectly increase surface roughness and asperity contacts. Gelatinized rice starch particles increase friction probably due to the stickiness of leached-out starch polymers. The presence of oil droplets in rice starch-o/w emulsions could reduce the friction caused by stickiness of gelatinized rice starch. The tribological behaviors of rice starch-emulsion-filled gels are more complex than liquids due to the bulk and breakdown properties of the gel matrix. We conclude that morphology and surface properties of the rice starch particles together with bulk and breakdown properties of matrices are the main factors determining the tribological properties of food model systems containing rice starch particles.

제분방법에 따른 분질, 연질 및 경질미 가루의 이화학적 특성

This study investigated the physicochemical properties of three different types of rice flour prepared via dry and wet milling. The powder, soft, and hard-types of rice flour were Suwon No. 542, Suwon No. 541, and Unbong No. 30, respectively. The analysis of the proximate compositions of the different types of rice flour showed that their moisture content was 7.03~7.99%, their crude protein was 7.94~8.35%, their crude lipid was 0.71~1.49% and their crude ash was 0.25~0.82%. For the Hunter’s color values, the L value was highest in the wet-milled rice flour, the a value was highest in the dry-milled rice flour, and the b value was highest in the dry-milled rice flour. All the samples showed distinctive rice starch particles in the particle analysis using scanning electron microscope. The dry-milled rice flour showed the greatest amount of irregular particles and the coarsest texture. The water absorption and water solubility indices were higher in the wet-milled soft- and hard-type rice flour. The crystallinities of the samples by X-ray diffractography were all A-type, but the crystallinity of the dry-milled hard-type rice flour was higher in diffraction degree. For the amylogram properties, the wet-milled soft-type rice flour showed the highest maximum viscosity, breakdown and setback. In the meanwhile, the dry-milled soft-type rice flour showed the highest initial pasting temperature, onset, peak, and end temperatures despite of the reverse enthalpy.

Predictive Evaluation of Heat Treatment Effect on Theophylline Release of Spray-Dried Pre-Gelatinised Glutinous Rice Starch Particles by near Infrared Spectroscopy

Starch is a natural polymeric with high chemical stability and no toxicity, so it is used widely as an additive in pharmaceutical manufacturing and the food industry. In this study, the effect of heat treatment on the controlled theophylline (TH) release rate of spray-dried pre-gelatinised glutinous rice starch (pGRS) was evaluated predictively by near infrared (NIR) spectroscopy. Spray-dried particles (SGRS) were obtained by spray-drying of TH ethanolic aqueous solution (TH: pGRS = 1: 1). The obtained SGRS was heat-treated to control drug release by chemical modification at 40–100°C. TH release test of the SGRS was performed to evaluate the drug release rate constant ( KH) in water at 37°C – body temperature. NIR spectra of heat-treated SGRS were recorded by diffuse reflectance NIR spectroscopy. The best calibration model consisted of five latent variables to predict KH and was determined by partial least squares (PLS) regression. Since the drug release profiles of TH from SGRS followed a Higuchi-type plot (diffusion-controlled sustained drug release), it was indicated that the rate-determining step of TH release is diffusion in polymeric matrices of SGRS. The KH of SGRS was evaluated based on Higuchi plots. It decreased with increasing temperature. X-ray diffraction and NIR results of SGRS suggested that TH recrystallised in SGRS after heat treatment. The relationship between actual and predicted KH values by our best PLS model based on NIR spectra gave a straight line with r2 = 0.990, with the slopes being close to 1. The KH of SGRS could be controlled by heat treatment. The KH could be predicted from NIR spectra and a chemometric method.

Preparation and characterizations of Pickering emulsions stabilized by hydrophobic starch particles

Soybean oil–in–water (O/W) Pickering emulsions were prepared using octenyl succinic anhydride (OSA) modified indica rice starch as particle stabilizers. The major factors affecting the emulsion stability were studied systematically. The rheological behaviors of the emulsions were also investigated by means of rheometer. Results indicated that the suitable parameters for the preparation of O/W Pickering emulsions stabilized by rice starch particles were selected as follows: concentration of starch particles 4.0 wt. % (degree of substitution 0.0287), soybean oil fraction 50 vol. %, pH of emulsion system 6.0–7.0. NaCl and sucrose concentrations had no obvious effect on the cream volumes of emulsions from 0 to 200 mmol/L. The rheological properties revealed that the Pickering emulsions showed a phenomenon of pseudo–plastic fluid characteristics. The elastic modulus (G′) was always higher than loss modulus (G″) at frequencies of 0.01–10 Hz. Moreover, G′ and G″ showed increasing trend with the increase in starch particle concentration. Microstructure of the Pickering emulsions showed that starch particles accumulated at the oil–water interface in the form of a densely packed layer. These results implied that an inter–droplet network probably formed, making the emulsions a gel–like behavior.

찰벼 품종별 이화학적 특성 및 물성 비교

This study was carried out to compare the varietal difference in physiochemical properties and textural properties of waxy rice cultivars. Crude protein had 5.9-7.2% varietal difference while crude lipid and crude ash contents were within the range of 0.8-2.0% and 0.3-0.6% and had a similar tendency as non-waxy rice. The amylose content was within the range of 1.79-1.93% and did not show significant differences among the tested cultivars. The water binding capacity of Hwaseonchal of the japonica cultivars scored the highest, Sinseonchal showed the lowest, while tongil-type Hangangchal showed a lower value, which can be due to a higher internal density. Baekseolchal showed the highest alkali digestion value and Sinseonchal showed the lowest. In amylogram characteristics, Baekseolchal showed the lowest value and Hwaseonchal and Sangjuchal showed higher initial temperature. Hangangchal scored higher in peak viscosity, breakdown viscosity, and final viscosity. It was prospective for all the cultivars to show slow retrogradations due to low setbacks compared to non-waxy rice and Hangangchal which showed the lowest setback. X-ray diffraction of waxy rice starch particles was typical A pattern. Hangangchal scored the highest and Hwaseonchal scored the lowest in crystallinity. One of the characteristics of cooked rice made from waxy rice is the hardness, which shows degrees of retrogradations, increased in storage time. Hangangchal showed a higher range of transformation with time and a higher retrogradation rate.

Venturing into In Vitro Physiological Upper GI System Focusing on the Motility Effect Provided by a Mechanised Rat Stomach Model

It is desirable to possess an in vitro digestion track model that can mimic to the fullest possible extent what is going on in a targeted animal system. Presently, there is still a long way before such a system becomes a reality despite a few attempts having been made in recent years to realise such a ‘dream’. Here, the design and laboratory experiences on a newly constructed in vitro rat stomach system are reported. Fine rice starch particles (obtained from cooked rice) have been used as the model food fed into the model stomach. Since the focus was on the motility effect, the microbial effect is neglected. The effects of motility rate and amplitudes of mechanical operation automated in the current rig have been focused upon and examined. The results are illustrative for a near-future development of a more effective construction of in vitro systems.

Natural Weathering of Poly (Lactic Acid): Effects of Rice Starch and Epoxidized Natural Rubber

Poly(lactic acid) (PLA) composites consisting of PLA, rice starch (RS), and epoxidized natural rubber (ENR50) are compounded using a twinscrew extruder followed by compression molding. Two types of thermoplastic starch are prepared by mixing RS with glycerol and water. Natural weathering tests are performed on the PLA/RS composites in Penang, Malaysia for 2 months. The average mean temperature and mean relative humidity are 29°C and 70%, respectively. Tensile tests are performed to characterize the mechanical properties of the weathered PLA/RS composites. Morphological studies are performed by using scanning electron microscopy (SEM). The tensile properties of weathered PLA/RS composites decreased slightly, on the other hand, the tensile properties of weathered PLA/SG and PLA/SGW composites decreased drastically. The retention-ability of the PLA composites are relatively low, which may be attributed to the photo-degradation of PLA, chain scission of PLA, oxidation degradation on ENR, moisture absorption of RS, and leaching of RS particles. In addition, discoloration, surface roughness, surface cracking, and embrittlement are observed for all PLA/RS composites. The extent of degradation is increased by the addition of ENR, owing to the fact that ENR is susceptible to oxygen attack, and consequently facilitates degradation. The morphological properties of the weathered PLA/RS composites are transformed to a more brittle behavior, indicating that severe degradation has occurred on the PLA/RS composites.

Water absorption and enzymatic degradation of poly(lactic acid)/rice starch composites

Poly(lactic acid) (PLA) composites consisting of PLA, rice starch (RS) (0–50 wt%) and epoxidised natural rubber (ENR50) were compounded by a twin-screw extruder and compression moulded into dumbbell specimens. Tensile tests were performed to characterize the mechanical properties of the PLA/RS composites. Morphological studies were done on the tensile fractured surface of the specimens by using scanning electron microscopy (SEM). Twenty weight percent of RS achieved a good balance of strength and stiffness. Beyond 20 wt% loading of RS, the tensile strength and elongation at break of PLA decreased drastically. This may be attributed to the agglomeration of RS, which could then act as stress concentrator. The incorporation of ENR50 increased the tensile strength and elongation at break of the PLA/RS composites remarkably, owing to the elastomeric behaviour and compatibilisation effects of ENR50. Interestingly, the morphology of PLA/RS composites transformed to a more ductile one with the addition of ENR. The kinetics of water absorption of the PLA/RS composites conforms to Fick's law. The M m and D values are dependent on the RS and ENR concentrations. The tensile properties of the PLA/RS composites deteriorated after water absorption. The retention-ability and recoverability of the PLA/RS composites are relatively low, attributed to the hydrolysis of PLA, degradation of the PLA–RS interface and leaching of the RS particles. In addition, the tensile properties of PLA/RS composites decreased drastically upon exposure to enzymatic degradation. Extensive pinhole and surface erosion on the PLA/RS composites indicate high degree of hydrolysis. Whilst the addition of ENR leads to some improvements in tensile properties, nevertheless, it enhanced the biodegradability of the PLA/RS composites when exposed to water and α-amylase enzymatic treatments.

Angular structure of radiation scattered by monolayers of particles: experimental study

An experimental study has been made of the angular structure of radiation scattered by monolayers of large nonabsorbing particles. We have investigated three media exhibiting different light-scattering properties: monodisperse polyvinyl toluene latex particles of 3.75-mum diameter suspended in water, polydisperse rice starch particles with a mean diameter of 6.4 mum suspended in water, and a mixture of ethyl and benzoic alcohols. It is shown that for large particles the structure of scattered radiation can be described in a single-scattering approximation. Analysis of the influence of polydispersity and the relative refractive index of particles on the intensity scattered by the monolayer has been performed.

A culture method of growing Entamoeba histolytica and other anaerobic amoebae for the study of their nuclear division.

THE mode of nuclear division in Entamoeba histolytica and other anaerobic amoebae is not clearly understood. There are two main reasons for this: first, difficulty is encountered in obtaining the various normal stages of nuclear division; second, unsuitable cytological techniques are used to distinguish between chromatic and non-chromatic substances. Dobell1 developed a culture method of obtaining large numbers of E. histolytica trophozoites in an actively growing condition. He grew amoebae by the Boeck–Drbohlav technique in a tube into which a coverglass was placed. The amoebae crept over the coverglass, where they continued their development, fed on the accompanying bacteria and rice starch and multiplied. Because they adhered to the glass, they could be readily obtained from the culture by removing the coverglass, and then fixed and stained. It should be emphasized that by this method large numbers of bacteria and rice starch particles also remain attached to the coverglass. This makes any study of nuclear structure and nuclear division difficult.