Physicochemical Properties of Rice Starch during Microwave Heating for Food Product Quality.

Rice starch is gradually used as a food ingredient. The characteristics of native starch are limited for using in some products. Therefore, microwave heating which is a non-chemically method was used for modify rice starch in this study. Changing of rice starch properties during microwave heating was investigated aimed for improving food product quality. Pasting properties of native starch (NS) showed the highest value for pasting temperature (66.8°C) and pasting viscosity (peak=3,583 cP, trough=1,542 cP, final=2,805 cP and setback=956 cP) than microwave treated rice starch (MRS) at 4 different time periods (10 s, 20 s, 30 s and 40 s). The results of pasting viscosity among MRS at 4 different time periods showed the lower values when increasing heating time. MRS at 40 s (MRS_40S) gave the lowest pasting temperature (52.9°C) which was needed lower temperature to gelatinize starch. NS had significant lower To (60.0°C), Tp (68.8°C), and Tc (75.5°C), and higher enthalpy (12.22 J/g) than the MRS. To, Tp and Tc of MRS was increased when treated time increasing, while enthalpy was decreased due to starch was gradually gelatinized and loss of crystallinity. XRD patterns of NS were found to be A-type because it showed peak of 2θ at 15°, 17°, 18° and 23° while XRD pattern of MRS_40S was changed and displayed peak only at 2θ (V-type). These changing of XRD patterns may due to loss of crystallinity during heating. The results indicated that microwave heating could change rice starch properties, especially MRS_40S displayed complete gelatinization. In addition, MRS_40S could be applied for using as texture improver for some food products which needs low viscosity e.g. soup, curry sauces and some beverages.

Gluten-Free Rice Breading Using Composited Rice Flour and Pre-Germinated Brown Rice Flour for Health Benefits.

Gluten-free rice breading (RB) is generally prepared by shredding of gluten-free rice bread. It is an alternative product for Celiac patients, who are gluten allergic. The aim of this research was to formulate gluten-free rice bread formula by using composited rice flour (RF) and pre-germinated brown rice flour (PGBRF) from two Thai rice cultivars, Pathum-Thani1 (15% amylose) and Phitsanulok2 (27% amylose) at the ratio of 1:1, by considering the structural properties of bread, health benefit of breading, and the properties of breading as coating material of fried frozen croquette (C-) and compared to those of samples prepared from wheat flour. Increasing PGBRF from 0% to 50% in gluten-free rice bread formula increased the puffed cell wall of air cell in gluten-free rice bread. Antioxidative activity of RB containing 50% PGBRF (RB-50%) was 4 and 9 times higher than RB without PGBRF (RB-0%) and wheat breading (WB), respectively. WB contained 356,289 mg/kg of gluten, while RB contained less than 2 mg/kg of gluten, which could be labeled "gluten-free". When compared all breading samples as coating material of C-, oil absorption of C-RB-50% (14.32%) was 3 times lower than that of WB (44.36%). Therefore, the RB-50% had health benefits for consumers who are suffered from Celiac disease and also other health-conscious consumers considering the higher antioxidative properties and lower oil uptake than the consumption of WB.

Development of gluten-free batter from three Thai rice cultivars and its utilization for frozen battered chicken nugget.

Rice flour based batter (RFBB) formulations were developed for deep-fat fried chicken nugget application. Ten combinations of the waxy rice (Rice Division6, RD6), low apparent amylose content (AAC) (Khao Dawk Mali105, KDML105) and high AAC rice (Rice Division31, RD31) were prepared according to the ten-point augmented simplex centroid mixture design. The AAC of RFBB samples ranged from 5.93 to 29.46% and contained less than 1 ppm of gluten content. After mixing rice flour (RF) with water at the ratio of 1:1.3, the decreased of apparent viscosities was found. Result showed that wheat flour based batter (WFBB) had higher wet pick-up (51.97%) than unblended RFBB (29.05-44.82%). However, the wet pick-up value was improved upon mixing three types of RF at various ratios. The RFBB formulas which contained high amount of dry-milled RD31 flour were more lightness and redness than others. These results suggested that the combination of RD6:KDML105:RD31 at the ratio of 16.7:16.7:66.7 provided the desirable RFBB as it contained similar AAC to WFBB. In addition, the coated chicken nugget with this sample tended to retain moisture content in both crust and core regions, and reduce oil content due to better oil resistance of RF than wheat flour.

Preparation of gluten-free rice spaghetti with soy protein isolate using twin-screw extrusion.

The objective of this study was to investigate the effect of soy protein isolate on functional properties and consumer acceptance of gluten-free rice spaghetti (GFRS) made from rice flour. Dry-milled high-amylose (Chai Nat 1) rice flour was premixed with dry-milled waxy (RD 6) rice flour at a ratio of 90:10 (w/w) with the soy protein isolate (SPI) concentration varying between 0, 2.5, 5.0, 7.5, 10.0 %, db. The GFRS formulation was processed using a co-rotating twin-screw extruder up to 95 °C with a screw speed of 220 rpm, 32 % moisture content, and then dried at 40 °C. The GFRS samples were analyzed by differential scanning calorimetry (DSC), X-ray diffraction, scanning electron microscopy (SEM) and texture parameters. Increasing SPI decreased the starch retrogradation of GFRS, whereas the enthalpy change of the amylose-lipid complex increased and crystallinity decreased. SEM revealed that the surface of GFRS containing SPI was much more porous than that of GFRS without SPI. The cooked GFRS containing 5.0 % SPI showed the best eating quality with increased firmness and tensile strength, and decrease stickiness. The GFRS samples were evaluated on the bases of cooking qualities and sensory evaluation. The results showed that the GFRS containing 5.0 % SPI decrease the cooking time from 17.6 to 13.7 min and cooking loss from 25.4 to 17.0 %. Overall acceptability of cooked GFRS containing 5.0 % SPI was the highest among all GFRS samples.

Influence of biopolymer emulsifier type on formation and stability of rice bran oil-in-water emulsions: whey protein, gum arabic, and modified starch.

Rice bran oil (RBO) is used in foods, cosmetics, and pharmaceuticals due to its desirable health, flavor, and functional attributes. We investigated the effects of biopolymer emulsifier type and environmental stresses on the stability of RBO emulsions. Oil-in-water emulsions (5% RBO, 10 mM citrate buffer) stabilized by whey protein isolate (WPI), gum arabic (GA), or modified starch (MS) were prepared using high-pressure homogenization. The new MS used had a higher number of octenyl succinic anhydride (OSA) groups per starch molecule than conventional MS. The droplet diameters produced by WPI and MS were considerably smaller (d < 300 nm) than those produced by GA (d > 1000 nm). The influence of pH (3 to 8), ionic strength (0 to 500 mM NaCl), and thermal treatment (30 to 90 °C) on the physical stability of the emulsions was examined. Extensive droplet aggregation occurred in WPI-stabilized emulsions around their isoelectric point (4 < pH < 6), at high salt (> 200 mM, pH 7), and at high temperatures (>70 °C, pH 7, 150 mM NaCl), which was attributed to changes in electrostatic and hydrophobic interactions between droplets. There was little effect of pH, ionic strength, and temperature on emulsions stabilized by GA or MS, which was attributed to strong steric stabilization. In summary: WPI produced small droplets at low concentrations, but they had poor stability to environmental stress; GA produced large droplets and needed high concentrations, but they had good stability to stress; new MS produced small droplets at low concentrations, with good stability to stress. Practical Application: This study showed that stable rice bran oil-in-water emulsions can be formed using biopolymer emulsifiers. These emulsions could be used to incorporate RBO into a wide range of food products. We compared the relative performance of whey protein, GA, and a new MS at forming and stabilizing the emulsions. The new OSA MS was capable of forming small stable droplets at relatively low concentrations.

Chicken eggshell matrix proteins enhance calcium transport in the human intestinal epithelial cells, Caco-2.

Chicken eggshell powder has been proposed as an attractive source of calcium for human health to increase bone mineral density in an elderly population with osteoporosis. However, factors affecting calcium transport of eggshell calcium have not yet been evaluated. Chicken eggshell contains about 1.0% (w/w) matrix proteins in addition to a major form of calcium carbonate (95%, w/w). In this study, we found that soluble eggshell matrix proteins remarkably enhance calcium transport using in vitro Caco-2 cell monolayers grown on a permeable support. The total calcium transport across Caco-2 monolayers showed an increase of 64% in the presence of 100 microg/well soluble eggshell matrix proteins. The active enhancer with a molecular mass of 21 kDa was isolated by reversed phase high-performance liquid chromatography and did not correspond to any previously identified protein. The N-terminal sequence was determined to be Met-Ala-Val-Pro-Gln-Thr-Met-Val-Gln. The possible mechanisms of eggshell matrix protein-mediated increase in calcium transport and the potential significance of eggshell calcium as a nutraceutical are discussed.