James Patindol

Fine Structures of Starches from Long-Grain Rice Cultivars with Different Functionality

ABSTRACT The structural features of rice starch that may contribute to differences in the functionality of three long-grain rice cultivars were studied. Dried rough rice samples of cultivars Cypress, Drew, and Wells were analyzed for milling quality, grain physical attributes, and starch structures and physicochemical properties. Drew was lower in head rice yield and translucency and higher in percentage of chalky grains compared with Cypress and Wells. Apparent amylose content (21.3–23.1%), crude protein (8.3–8.6%), and crude fat (0.48–0.64%) of milled rice flours were comparable, but pasting properties of rice flours as measured by viscoamylography, as well as starch iodine affinity and thermal properties determined by differential scanning calorimetry were different for the three cultivars. Drew had higher peak, hot paste, and breakdown viscosities, and gelatinization temperature and enthalpy. Molecular size distribution of starch fractions determined by high-performance size-exclusion chromatography s...

Functional Properties as Affected by Laboratory‐Scale Parboiling of Rough Rice and Brown Rice

Rough rice (RR) is the conventional feedstock for parboiling. The use of brown rice (BR) instead of RR is gaining interest because it results in shorter processing time and lower energy requirement. This study compared the functional properties of milled parboiled rice under different parboiling conditions from RR and BR. Presoaked RR and BR from cultivars Bolivar, Cheniere, Dixiebelle, and Wells were parboiled under mild (20 min, 100 degrees C, 0 kPa) and severe (20 min, 120 degrees C, 98 kPa) laboratory-scale conditions. Head rice yield improved on the RR and BR samples subjected to severe parboiling and was comparable to that of a commercially parboiled sample. Mild parboiling of BR resulted in lower head rice yields. Parboiling generally resulted in decreased head rice whiteness, decreased apparent amylose, increased total lipid, and sparingly changed protein content. Under the same parboiling conditions, the extent of starch gelatinization was higher for BR compared to RR as manifested by some distinct differences in pasting and thermal properties. The cooking characteristics (water uptake ratio, leached materials, and volumetric expansion) and cooked rice texture (hardness and stickiness) of RR and BR subjected to severe parboiling were fairly comparable. Differences in parboiled rice functional properties due to cultivar effect were evident.

Properties of Flours and Starches as Affected by Rough Rice Drying Regime

ABSTRACT Flours and starches from rough rice dried using different treatment combinations of air temperature (T) and relative humidity (RH) were studied to better understand the effect of drying regime on rice functionality. Rough rice from cultivars Bengal and Cypress were dried to a moisture content of ≈12% by three drying regimes: low temperature (T 20°C, RH 50%), medium temperature (T 40°C, RH 12%), and high temperature (T 60, RH 17%). Head rice grains were processed into flour and starch and evaluated for pasting characteristics with a Brabender Viscoamylograph, thermal properties with differential scanning calorimetry, starch molecular-size distribution with high-performance size-exclusion chromatography (HPSEC), and amylopectin chain-length distribution with high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Lower head rice and starch yields were obtained from the batch dried at 60°C which were accompanied by an increase in total soluble solids and total ...

Properties and structures of flours and starches from whole, broken, and yellowed rice kernels in a model study

ABSTRACT The objective of this study was to compare the structure and properties of flours and starches from whole, broken, and yellowed rice kernels that were broken or discolored in the laboratory. Physicochemical properties including pasting, gelling, thermal properties, and X-ray diffraction patterns were determined. Structure was elucidated using high-performance size-exclusion chromatography (HPSEC) and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The yellowed rice kernels contained a slightly higher protein content and produced a significantly lower starch yield than did the whole or broken rice kernels. Flour from the yellowed rice kernels had a significantly higher pasting temperature, higher Brabender viscosities, increased damaged starch content, reduced amylose content, and increased gelatinization temperature and enthalpy compared with flours from the whole or the broken rice kernels. However, all starches showed similar pasting, gelling, ther...

Nutritionally Important Starch Fractions of Rice Cultivars Grown in Southern United States

Dietary starches can be classified into 3 major fractions according to in vitro digestibility as rapidly digestible (RDS), slowly digestible (SDS), and resistant starch (RS). Literature indicates that SDS and/or RS have significant implications on human health, particularly glucose metabolism, diabetes management, colon cancer prevention, mental performance, and satiety. In this study, the nutritionally important starch fractions (RDS, SDS, and RS) in cooked rice were assayed in vitro, making use of 16 cultivars grown in 5 southern U.S. rice growing locations (Arkansas, Louisiana, Mississippi, Missouri, and Texas). RDS, SDS, and RS were 52.4% to 69.4%, 10.3% to 26.6%, and 1.2% to 9.0%, respectively, of cooked rice dry weight. Cultivar, location, and cultivar-by-location interaction contributed to the variations in RDS, SDS, and RS contents. Means pooled across locations indicated that SDS was higher for the Louisiana samples than those from Texas, whereas RS was higher for the Texas samples than those from Arkansas, Louisiana, and Mississippi. Some cultivars were identified to possess high levels of RS (for example, Bowman and Rondo) or SDS (for example, Dixiebelle and Tesanai-2) and were also stable across growing locations. Apparent amylose content correlated positively with RS (n = 80, r = 0.54, P <or= 0.001), negatively with RDS (n = 80, r =-0.29, P <or= 0.05), and insignificantly with SDS (n = 80, r = 0.21, P > 0.05). RS and SDS were not collinear (n = 80, r =or-0.18, P > 0.05); it does not follow that a cultivar high in RS will also be high in SDS, and vice versa. The observed differences in RDS, SDS, and RS among the samples are indicative of wide genetic diversity in rice.

Impact of Elevated Nighttime Air Temperatures During Kernel Development on Starch Properties of Field-Grown Rice

ABSTRACT The structural features of starch were examined to better understand the causes of variability in rice quality resulting from nighttime air temperature (NTAT) incidence during kernel development. Starch samples were isolated from head rice of four cultivars (Bengal, Cypress, LaGrue, and XL723) field-grown in four Arkansas locations (Keiser, Pine Tree, Rohwer, and Stuttgart) in 2009 and 2010. Average NTATs recorded during the grain-filling stages of rice reproductive growth in the four locations were 3.0–8.4°C greater in 2010 than 2009. Elevated NTATs altered the deposition of starch in the rice endosperm. Means pooled across cultivars and locations showed that amylose content was 3.1% (percentage points) less for the 2010 sample set. The elevated NTATs in 2010 resulted in a decrease in the percentage of amylopectin short chains (DP ≤ 18) and a corresponding increase in the percentage of long chains (DP ≥ 19) by an average of 1.3% (percentage points). The greater NTATs in 2010 also produced greate...

Functional Properties of Commingled Rice-Cultivar Lots

ABSTRACT Commingling of rice cultivars commonly occurs during harvest, drying, and storage operations. Because different cultivars often have different functional properties, there is a need to study the impact of commingling on these properties. Two long-grain hybrid (H) cultivars, CL XL745 and CL XL729, and two long-grain pureline (P) cultivars, CL 151 and Wells, were used to prepare H/P, H/H, and P/P commingles in various proportions. Gelatinization and pasting properties of all individual lots and commingled samples were measured. When two cultivar lots with different onset gelatinization temperatures (Tos) were commingled, the To of the commingled sample was similar to the To of that cultivar in the commingle with the lower To. Tps, Tcs, and ΔHs of commingled samples generally increased or decreased according to the mass percentages of the cultivars in the samples. Peak, breakdown, and final viscosities of commingled samples also varied according to the mass percentages of the cultivars in the commin...

Storage Stability of Flour-Blasted Brown Rice

ABSTRACT Brown rice was blasted with rice flour rather than sand in a sand blaster to make microperforations so that water could easily penetrate the brown rice endosperm and cook the rice in a shorter time. The flour-blasted American Basmati brown rice, long-grain brown rice, and parboiled long-grain brown rice samples were stored in Ziploc storage bags under atmospheric conditions and in vacuum-packed bags. They were periodically tested for over 10 months for changes in water absorption, free fatty acid (FFA), peroxide value (POV), viscosity changes of flour using the Rapid ViscoAnalyser (RVA), and texture of whole cooked kernel using a texture analyzer during cooking. Flour-blasted brown rice absorbed less water but needed less cooking time than its counterpart that was not flour-blasted. There was an increase in FFA, POV, peak viscosity (PV), final viscosity (FV), breakdown viscosity (BD), and setback viscosity (SB) during storage of flour-blasted brown rice for 300 days, but no change was observed in...

Kernel and Starch Properties of U.S. and Imported Medium- and Short-Grain Rice Cultivars

The production of medium- and short-grain rice in the mid-Southern U.S. rice-growing region is increasing. This work aimed to identify the quality traits of importance to the markets for these grain types. Twenty-five medium- and short-grain milled rice samples were collected and analyzed for physical, gelatinization, pasting, and starch structural properties. Six samples were from Arkansas (AR), five from California (CA), and 14 imported (IM). Cluster and principal component analyses showed that the AR samples had greater gelatinization temperature, enthalpy, and percentages of amylopectin long chains (B2 and B3 chains) but lesser kernel whiteness, total setback viscosity, and percentage of amylopectin short chains (A chains) than the CA samples. With the exception of one sample from Taiwan, chemometrics indicated that the IM samples differed from the AR samples (cluster A) in some properties and were grouped into three clusters (clusters B, C, and D). Cluster B samples had properties that were similar t...

Impact of Feedstock, Parboiling Condition, and Nutrient Concentration on Simultaneous Fortification of Two U.S. Long-Grain Rice Cultivars with Iron and Zinc

This work investigated the effect of parboiling on simultaneous fortification of rice with iron (Fe) and zinc (Zn) using rough rice and brown rice as feedstocks. Three fortificant concentrations (0, 100, and 200 mg/L for both Fe and Zn) were tested, and two long-grain rice cultivars (CLXL745 and RoyJ) were used as test samples. Cultivar had little impact on the retention of Fe and Zn; steaming combined with soaking significantly increased the migration of Fe and Zn into the endosperm compared with soaking only. The Fe and Zn contents of the resultant parboiled head rice were related to the initial concentrations in the soaking water and were 7.2–17.6 and 21.8–31.9 mg/kg, respectively, when rough rice was used as a feedstock, and they significantly increased to 32.4–84.9 mg/kg for Fe and 45.8–78.4 mg/kg for Zn when brown rice was used as a feedstock. Mineral retention after simulated washing was 87.5–95.1% for Fe and 81.1–84.3% for Zn. Dilute-HCl extractability as an indicator of mineral bioavailability wa...