Comparison of Protein Extraction Solutions for Rice Starch Isolation and Effects of Residual Protein Content on Starch Pasting Properties

Protein extraction solutions such as aqueous solutions of sodium hydroxide (0.1 and 0.2 %), sodium lauryl sulfate (SLS, 1.2 %) containing sodium sulfite (0.12 %), and dodecylbenzene sulfonate (DoBS, 1.2 %) containing sodium sulfite (0.12 %) were compared in their protein removal efficiencies during isolation of starch from a rice flour (Ilpumbyo, a nonwaxy Korean rice variety). In addition, the pasting properties of the isolated starch was compared. More than 80 % of the flour protein was extracted in 1 h by stirring the dispersion (1:3, w/v) at room temperature. Repeating the extractions (1 or 2 h for each step) with fresh solution significantly increased the protein removal efficiency. When the extraction in 0.2 % NaOH was repeated four times (1 h for each step) at 25°C, the residual protein content in the isolated rice starch was 0.9 % (DB), equivalent to 86 % removal of the rice protein. Raising the extraction temperature slightly increased the protein solubility, but starch loss also became significant. Among the solutions, DoBS was most effective in removing rice protein whereas SLS was least. The residual protein content had a critical role in determining the pasting characteristics of the isolated starch, showing a negative correlation to the peak viscosity of the starch paste, but a positive correlation to the pasting temperature.     

Effect of heat-moisture treatment for utilization of germinated brown rice in wheat noodle

Effect of heat-moisture treatment of germinated brown rice (GBR) on the texture and cooking quality of the noodles containing mixtures of wheat and GBR flours was investigated. With the increase in GBR content, hardness and tensile strength of the composite noodles decreased and cooking loss and water absorption increased. Pasting viscosity of the flour mixtures was significantly decreased by increasing the amount of GBR. Heat-moisture treatment of GBR (17 or 20 g/100 g moisture at 100 °C for 4 h), however, apparently increased the pasting viscosity and improved the texture and cooking quality of the composite noodles. The mixture of wheat and a treated GBR (1:1 weight ratio) showed a pasting viscosity similar to pure wheat flour. The noodle containing the heat-moisture treated GBR flours showed the lower cooking loss, and higher hardness and tensile strength than the noodle containing untreated counterparts. Among the treated GBR flours tested, the GBR treated at 100 °C for 4 h at a moisture level of 17 g/100 g was the most acceptable in terms of cooking quality and textural property, close to those of the noodle of pure wheat flour. Substitution with the heat-moisture treated GBR, however, made the noodle darker because of thermal discoloration of GBR.     

Effect of Amino Acids and Peptides on Mixing and Frozen Dough Properties of Wheat Flour

Free amino acids, peptides, and vital wheat gluten were investigated to determine their effect on the mixing and frozen dough baking properties of wheat flour. Addition of 1% cysteine and aspartic acid decreased and glutamic acid, histidine, arginine, and lysine increased the mixing tolerance of flour. Cystine, methionine, tryptophan, and phenylalanine increased but isoleucine, histidine, glycine, arginine, glutamic acid, aspartic acid, and lysine decreased loaf volume of nonfrozen dough breads. However cystine, methionine, tryptophan, and phenylalanine did not increase loaf volume of bread prepared from frozen dough. Vital wheat gluten increased mixing tolerance and bread loaf volume only for the nonfrozen dough. However, wheat gluten hydrolysate, corn, and bonito peptides decreased mixing tolerance after optimum mixing time and were effective in increasing loaf volume for both frozen and nonfrozen dough. As the amount of corn and bonito peptide increased, specific loaf volumes also increased. Addition of 2.5% corn peptide was most effective in increasing loaf volume of frozen dough bread. Crust browning and crumb stickiness increased, whereas crumb softness decreased with addition of peptides. Addition of less than 1% peptide did not adversely affect the aftertaste and off‐flavor of bread. These results suggest that addition of peptides are effective for improving the baking quality of frozen dough, whereas amino acids and gluten have no effect.     

In vitro cosmeceutical activity of alcoholic extract from chestnut inner shell fermented with Aspergillus sojae

Food Science and Biotechnology - Chestnut inner shell was fermented in solid state with Aspergillus sojae, and then extracted using ethanol (95%) to analyze its cosmeceutical activity and phenolic...     

Substitution of corn starch with polycaprolactone via chlorination and water resistance of the substituted starch

Corn starch was chlorinated using methanesulfonyl chloride in dimethylformamide (DMF) and then substituted with polycaprolactone (PCL) in various solvents [dimethylsulfoxide (DMSO), water and dimethylacetamide (DMAc)] containing a catalyst [sodium hydroxide (NaOH) or lithium chloride (LiCl)] to improve water resistance. The reaction yield based on the product weight was highest (85%) when DMAc and LiCl were used. Fourier transform infrared (FTIR) spectra showed that starch was monosubstituted with PCL in the aqueous NaOH solution, whereas it was to crosslink by PCL in the case using DMAc and LlCl. The intrinsic viscosity of the products in DMSO supports these trends. By introducing the hydrophobic PCL onto starch, solvent resistance of the substituted starches to water and other aqueous media increased. The crosslinked starch displayed higher water resistance than the monosubstituted starch. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2197–2202, 2001     

Characterisation of 2-octen-1-ylsuccinylated waxy rice amylodextrins prepared by dry-heating

Waxy rice amylodextrins substituted with 2-octen-1-ylsuccinic acid (OSA) were prepared by heating a dried mixture of waxy rice starch and OSA (3% OSA based on starch solids) at 130–150 °C and pH 3–5 for 1–3 h. The effects of the heating conditions, such as pH, temperature and heating time on the degrees of substitution (DS) and dextrinisation, and the physical properties of the dextrins were evaluated. Substitution and dextrinisation were more affected by the reaction pH than by the physical conditions (temperature and time). Heating under a more acidic condition resulted in a higher DS and a lower molecular weight (M_w). Pasting viscosity profiles showed reduced pasting temperatures but increased peak viscosities, due to the presence of OSA, compared to unsubstituted dextrin counterparts. The X-ray diffraction patterns of the OSA dextrins were similar to that of the native starch, indicating that the dextrinisation occurred mainly in the amorphous regions of the starch granules. Fat-free whipped creams were prepared with the OSA dextrins and skim milk powder to examine the fat-replacing effects of the dextrins. The OSA dextrins effectively substituted the fat in dairy cream, providing good foaming ability and storage stability.     

Preparation of aqueous dispersion of β-carotene nano-composites through complex formation with starch dextrin

Aqueous dispersions of β-carotene nano-composite were prepared through a blending process with a dextrin of high amylose corn starch in immiscible phases of aqueous dextrin and organic β-carotene solutions and water solubility and stability against oxidation of β-carotene were examined. Gradual evaporation of organic solvent during the mechanical stirring allowed the formation of aqueous solutions in which β-carotene was homogeneously dispersed with dextrin. Proper control of the solid concentrations effectively induced the complex formation between dextrin and β-carotene whereas an excess amount of β-carotene (>8 mg) in a dextrin solution (200 mg in 50 mL) induced crystallization and precipitation of β-carotene. The complex particles showed an irreversible endothermic transition of V-amylose (via DSC). X-ray diffraction analysis, however, revealed that the complex had no typical V-type crystalline arrangement. Hydrodynamic size of the complex particles in the aqueous solution could be decreased to nano-scale (16–30 nm) by a mild ultrasonication. The nano-composite contained β-carotene at approximately 30% on a weight, with improved stabilities against oxidation and enzymatic digestion.     

Comparison of physicochemical characteristics and consumer perception of rice samples with different countries of origin and prices

BACKGROUND: Rice is the only food item which is not liberalized in Korea. To prepare for future liberalization of the rice market in Korea, the physicochemical characteristics and consumer perception of four domestic rice samples were compared with those of 11 foreign rice samples. Additionally, the influences of country of origin (CO) and price on purchase intent (PI) and willingness to pay (WTP) were investigated. RESULTS: Consumer acceptance of rice samples from Japan was generally higher than that of rice samples from other countries. In an informed test, PI was affected by price and CO, while WTP was affected mostly by price. The PI decreased with the price provided while the WTP increased. In a blind test, consumers evaluated PI and WTP according to sensory liking. The PI was higher in the informed test than in the blind test in all domestic samples. Generally, consumer acceptance was highly correlated with fat acidity (r = ? 0.76), protein content (r = ? 0.72), and b value (r = ? 0.64) of the rice samples. CONCLUSION: Further efforts to increase the quality of rice are recommended for survival in the global market after liberalization of rice, even though consumers showed loyalty for PI of domestic samples. Copyright © 2011 Society of Chemical Industry     

Protective effect of Perilla frutescens cv. Chookyoupjaso mutant water extract against oxidative injury in vitro and in vivo

The aim of this study was to elucidate the protective ability of the Perilla frutescens cv. Chookyoupjaso mutant water extract (PFWE) against oxidative injury in vitro and in vivo. In in vitro experiments, our results showed that PFWE indicated the intracellular reactive oxygen species (ROS) scavenging activity as well as cytoprotective effect in SIN-1-treated HepG2 cells. The intracellular ROS scavenging activity of PFWE was 44% at 50 μg/mL, 50% at 100 μg/mL, and 56% at 200 μg/mL. Furthermore, in vivo results showed that treatment with PFWE attenuated the activity of serum alkaline phosphatase (ALP) and lipid peroxidation increased by carbon tetrachloride (CCl₄) and also markedly recovered the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) decreased by CCl₄ in BALB/c mice. GPx activity was elevated almost 3-fold compared to control group at 50 mg/kg of PFWE. The present study suggests that PFWE possesses significant protective effects against oxidative injury.     

Utilization of rice starch with gums in Asian starch noodle preparation as substitute for sweet potato starch

Starch noodles were produced using a medium grain rice starch in the presence of various gums, and physical properties of the noodles were compared with sweet potato starch noodle. Pasting viscosity of the rice starch was lower than that of sweet potato starch (830 vs. 1,618 cp as peak viscosity). The peak viscosity, however, was increased by the addition of gums (0.1% based on dispersion), and especially xanthan was the most effective in increasing the peak viscosity (1,478 cp). The cooking loss for the rice starch noodles (1.5 mg/mL), greater than that for the sweet potato starch noodle (0.2 mg/mL), was effectively reduced to 0.8 and 0.9 mg/mL, respectively, by the addition of locust bean gum (LBG) and curdlan. The addition of LBG or gellen gum also increased the hardness of the rice noodles. Aging (extended retrogradation) the noodles was effective in reducing the cooking loss and improving the textural properties of the rice starch noodles. The combination of the gum addition (like LBG) and aging of the rice starch noodle might be useful for utilizing rice starch as a substitute for sweet potato starch in Asian noodle preparation.