Studies on Quality of Potato Flour Blends with Rice Flour for Making Extruded Noodles

The effects of rice flour on the physicochemical properties of the raw material system and the quality of extruded potato–rice noodles were studied. The results demonstrated that the amylose content, pasting viscosities, storage modulus (G′), and loss modulus (G″) gradually increased with the included levels of rice flour, whereas the swelling power, solubility, and pasting temperature decreased with increasing rice flour content. The extruded potato–rice noodles exhibited desirable cooking qualities and textural properties with rice flour contents of up to 40%. Additionally, sensory evaluations revealed that the scores for chewiness, firmness, slipperiness, elasticity, and overall acceptability increased gradually with increasing rice flour content in the blends. Additionally, the results indicated the possibility of replacing potato flour with rice flour at a ratio of 6:4 to produce extruded potato–rice noodles of acceptable quality.     

Composite Durum Wheat Flour/Plantain Starch White Salted Noodles: Proximal Composition,Starch Digestibility,and Indigestible Fraction Content

In search of a way to improve the nutritional profile of noodles, we prepared them with various mixtures of durum wheat flour and isolated plantain starch, and tested their proximal composition. Cooked noodles were assessed for in vitro starch digestibility, indigestible fraction content, and predicted glycemic index. The protein content declined with the addition of plantain starch. Both total starch (TS) level and the content of starch available for digestible enzymes (AS) decreased as the plantain starch level increased, a pattern that may be related to increased starch lixiviation during cooking of noodles containing plantain starch. There was an inverse pattern for resistant starch (RS). RS content in control (durum wheat flour) noodles was ≈50% lower than in the samples containing plantain starch. The soluble indigestible fraction (SIF) content in all samples was higher than the insoluble counterpart (IIF). The total indigestible fraction varied according to the wheat substitution level. Although the hydrolysis index (HI) and predicted glycemic index (pGI) of plantain starch noodles were moderate and decreased as the plantain starch proportion rose. These composite noodles exhibited higher indices than the control sample, a phenomenon that may also be dependent on the product physical structure. Results indicate that in spite of the increased starch digestion rate, plantain starch noodles are a better source of indigestible carbohydrates than pure wheat starch pasta. This might have dietetic applications.     

Effect of Whole Grain Wheat Flour on the Mixing Properties,Oil Uptake,and In Vitro Starch Digestibility of Instant Fried Noodles

The effects of whole grain wheat (WGW) flour on the quality attributes of instant fried noodles were characterized in terms of mixing and oil‐resisting properties as well as in vitro starch digestibility. Higher water absorption and shorter kneading time were required to obtain the optimally mixed dough from WGW flour, and the presence of nonstarch components in the WGW flour lowered the thermal conductivity of the noodles. The use of WGW flour produced instant fried noodles with oil uptake reduced by 30%, which could be correlated with the less porous structure confirmed by the surface and cross‐sectional scanning electron microscope images. When the instant fried noodles were subjected to in vitro starch digestion, the use of WGW flour was effective in suppressing the hydrolysis of starch in the noodles, and the predicted glycemic index of the WGW noodles (80.6) was significantly lower than that of the white wheat noodles (83.3).     

Modeling Selected Properties of Extruded Rice Flour and Rice Starch by Neural Networks and Statistics

Rice flour and rice starch were single‐screw extruded and selected product properties were determined. Neural network (NN) models were developed for prediction of individual product properties, which performed better than the regression models. Multiple input and multiple output (MIMO) models were developed to simultaneously predict five product properties or three product properties from three input parameters; they were extremely efficient in predictions with values of R² > 0.95. All models were feedforward backpropagation NN with three‐layered networks with logistic activation function for the hidden layer and the output layers. Also, model parameters were very similar except for the number of neurons in the hidden layer. MIMO models for predicting product properties from three input parameters had the same architecture and parameters for both rice starch and rice flour.     

Effects of Oxido-Reductants on Rheological Properties of Wheat Flour Dough and Comparison with Some Characteristics of Extruded Noodles

The effects of oxido-reductants on the rheological properties of wheat flour dough were evaluated by using a capillary rheometer and an oscillatory rheometer at three temperatures. The oxidants potassium iodate (KIO₃) and l -ascorbic acid (l -AA) significantly increased the apparent viscosity and G′ and decreased loss tangent at low temperatures of 30 and 60°C due to enhanced formation of disulfide bonds. The reductant glutathione (GSH) had the opposite effect. Heating caused the gelatinization of starch, which diminished the effects of the oxido-reductants and produced doughs with similar rheological properties at 80°C. The correlation between dough rheology and characteristics of extruded noodles was also studied.     

Physicochemical Properties of Starch in Extruded Rice Flours

The effects of extruding temperatures and subsequent drying conditions on X‐ray diffraction patterns (XRD) and differential scanning calorimetry (DSC) of long grain (LG) and short grain (SG) rice flours were investigated. The rice flours were extruded in a twin‐screw extruder at 70–120°C and 22% moisture, and either dried at room temperature, transferred to 4°C for 60 hr, or frozen and then dried at room temperature until the moisture was 10–11%. The dried materials were milled without the temperature increasing above 32°C. XRD studies were conducted on pellets made from extruded and milled flours with particle sizes of 149–248 μm; DSC studies were conducted from the same material. DSC studies showed that frozen materials retrograded more than the flours dried at room temperature. The LG and SG samples had two distinct XRD patterns. The LG gradually lost its A pattern at >100°C, while acquiring V patterns at higher temperatures. SG gradually lost its A pattern at 100°C but stayed amorphous at the higher extruding temperatures. DSC analysis showed that retrograded flours did not produce any new XRD 2θ peaks, although a difference in 2θ peak intensities between the LG and SG rice flours was observed. DSC analysis may be very sensitive in detecting changes due to drying conditions, but XRD data showed gradual changes due to processing conditions. The gradual changes in XRD pattern and DSC data suggest that physicochemical properties of the extruded rice flours can be related to functional properties.     

Instrumental Measurement of Physical Properties of Cooked Asian Wheat Flour Noodles

Instrumental texture tests on cooked noodles are valuable research tools and are well suited for monitoring noodle texture after changes in formulations, raw materials, and processing. Uniaxial tests are most common, and a variety of test types, strains, strain rates, and probe dimensions are used. Consequently, standardization is a challenge. Compressive tests (cutting and blunt probe compression) are more frequently reported than tensile tests. Combining results of tensile and compressive tests shows potential to uncover aspects of noodle texture not detectable using one method alone. Tensile and blunt‐probe compression tests can be both adapted for stress relaxation experiments and may be used to derive fundamental rheological information. Dynamic oscillating rheometry shows promise as a tool for investigating composition/structure/function relationships in cooked noodles. However, unlike large deformation “texture” tests, dynamic oscillating rheometry struggles to match sensory perceptions of noodle texture. This may result from the scale of the deformations applied, which are commonly much smaller than the deformations required for rupture. Limitations of small deformations become more evident when considering fracture properties of noodles and how these are affected by changes in flour composition and inhomogenieties in noodle structure at the macro‐, meso‐, and micro‐scales. Combining information from small and large deformations has been used to investigate changes in noodle texture occurring after changes in amylose and protein composition. This combined approach may prove to be useful in resolving differences and similarities in noodle texture wrought by changes in the constituent polymers of wheat flour.     

不同地区再生季稻米蒸煮食味品质及淀粉结构与性能差异研究

为探究再生季稻米蒸煮食味品质在不同生态区的差异,并从淀粉结构与性能角度揭示其差异机理,本试验以杂交稻甬优4149、晶两优1468为供试材料,按再生稻栽培模式分别种植于肇庆、长沙、信阳3个生态区,研究了再生季齐稳后温光条件对稻米蒸煮食味品质、RVA谱特性及淀粉热性能和晶体结构的影响.结果 表明,肇庆试验地区的再生季稻米蒸...     

Effect of Ultrasonic Treatment of Brown Rice at Different Temperatures on Cooking Properties and Quality

This research studied developing quick cooking brown rice by investigating the effect of ultrasonic treatment at different temperatures on cooking time and quality. The medium grain brown rice was ultrasonically treated in water at temperatures of 25, 40, and 55°C for 30 min and then dried by air at 25°C to its initial moisture content (11.0 ± 0.6%, wb) before cooking. The microstructure of rice kernel surface, chemical composition, and optimal cooking time of treated brown rice were determined. The pasting and thermal properties and chemical structure of flour and starch from treated brown rice were also examined. The results showed that the optimal cooking times were 37, 35, and 33 min after treatment at 25, 40, and 55°C, respectively, compared to the control of 39.6 min. The ultrasonic treatment resulted in a loss in natural morphology of rice bran, allowing water to be absorbed by a rice kernel easily, particularly at high‐temperature treatment. Even through rice flour still maintained an A‐pattern in the pasting properties, the crystallinity significantly increased after treatment at 55°C. Ultrasonic treatment increased the peak, hold, and final viscosities and decreased the onset temperature (T_o) and peak temperature (T_p), significantly. Thus, ultrasonic treatment could be used for reducing cooking time of brown rice.     

Enhancement of Nutritional and Antioxidant Properties of Brown Rice Flour Through Solid‐State Yeast Fermentation

This study investigated the effect of solid‐state yeast fermentation on the nutritional and antioxidant properties of brown rice flour (BRF). Three brands of commercial baker's yeast (Eagle, Saf‐levure, and Mauripan) were used to ferment BRF at 25°C for 12 h. There were significant increases in protein, ash, insoluble and soluble fiber, phosphorus, zinc, magnesium, calcium, and iron contents after yeast fermentation. Fermented BRF with Eagle yeast possessed the highest contents of protein, ash, zinc, and calcium. Fermentation of BRF with Eagle yeast was more effective in increasing antioxidant activity and total phenolic contents from 1.01 to 1.54 mmol of Trolox equivalents per gram and from 1.09 to 1.21 mg of gallic acid equivalents per gram, respectively. Yeast fermentation reduced phytic acid content of BRF (124.59 ± 0.48 µg/g), and the Eagle yeast‐fermented sample had the lowest value (36.55 µg/g) compared with the other fermented samples. Fermented flour with Eagle yeast also had the highest α‐amylase activity, because it recorded the lowest stirring number. Solid‐state fermentation with commercial yeast, particularly Eagle yeast, was effective in improving the nutritional and antioxidant properties of underutilized BRF as a food ingredient.     

Relationship Between Physicochemical Properties of Wheat Flour,Wheat Protein Composition,and Textural Properties of Cooked Chinese White Salted Noodles

Physicochemical properties and protein composition of 39 selected wheat flour samples were evaluated and correlated with the textural properties of Chinese hard‐bite white salted noodles. Flour samples were analyzed for their protein and wet gluten contents, sedimentation volume, starch pasting properties, and dough mixing properties by farinograph and extensigraph. Molecular weight distribution of wheat flour proteins was determined with size‐exclusion (SE) HPLC, SDS‐PAGE, and acid‐PAGE. Textural properties of Chinese hard‐bite white salted noodles were determined through texture profile analysis (TPA). Hardness, springiness, gumminess, and chewiness of cooked noodles were found to be related to the dough mixing properties. Both protein content and protein composition were found to be related to TPA parameters of noodles. The amount of total flour protein was positively correlated to hardness, gumminess, and chewiness of noodles. The absolute amounts of different peak proteins obtained from SE‐HPLC data showed positive correlations with the hardness, gumminess, chewiness, and springiness of noodles. The proportions of these peak proteins were, however, not significantly related to texture parameters. The proportions of low‐molecular‐weight glutenins/gliadins and albumins/globulins, as observed from SDS‐PAGE, were correlated positively and negatively, respectively, to the hardness, gumminess, and chewiness of cooked noodles. Among the alcohol‐soluble proteins (from acid‐PAGE data), β‐gliadins showed strong correlations with the texture properties of cooked noodles. For the selected flour samples, the total protein content of flour had a stronger relationship with the noodle texture properties than did the relative proportion of different protein subgroups. Prediction equations were developed for TPA parameters of cooked noodles with SE‐HPLC and rapid visco analysis data of the 30 flour samples, and it was found that about 75% of the variability in noodle hardness, gumminess, and chewiness values could be explained by protein composition and flour pasting properties combined together. About 50% of the variations in cohesiveness and springiness were accounted for by these prediction equations.     

豌豆粉添加对米粉品质特性的影响

为了提高米粉的营养价值,本研究将不同粒径的豌豆粉添加到米粉中,分析不同粒径及添加量(0％、7.5％、15％、30％)对大米粉粉质特性及米粉蒸煮、质构和感官特性的影响.结果 表明,添加豌豆粉可以增加米粉中蛋白质的含量,添加30％豌豆粉后米粉的蛋白质含量为原米粉的1.73倍.豌豆粉的添加降低了米粉的峰值黏度、最终黏度和回生...     

Physicochemical Properties Related to Quality of Rice Noodles

Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = -0.65, P < 0.05), flour swelling volume (FSV) (r = -0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.     

Structure,Physicochemical Properties,and In Vitro Starch Digestibility of Yellow Pea Flour Modified with Different Organic Acids

The objective of this study was to produce a pea flour ingredient with higher slowly digestible (SDS) and resistant (RS) starch fractions for functional food applications. Heat‐moisture treated flour (HMTF) in the presence of citric, gallic, or vanillic acids and esterified flour (EF) with citric acid were prepared and analyzed for structure and functionality using in vitro starch digestibility, differential scanning calorimetry, Rapid Visco Analyzer, swelling factor (SF), amylose leaching (AML), optical microscopy, and Fourier transform infrared (FT‐IR) spectroscopy. Significant (P < 0.05) increases in SDS and RS content of HMTF and EF were observed. Whereas the granule integrity and the birefringence were not affected by modification, the degree of crystalline order, which was determined by FT‐IR 1,047/1,022 cm⁻¹ peak ratio, was decreased. Gelatinization enthalpies of modified flour were lower than that of native flour, whereas the gelatinization endotherms of HMTF were shifted to higher temperatures and those of EF to lower temperatures. Pasting properties were also affected greatly by both treatments. HMTF demonstrated reduced SF and AML, whereas EF had reduced SF and increased AML. Further, the extent of changes in the structure and functionality of HMTF depended on the type of acid utilized. Overall, heat‐moisture treatment with an organic acid and esterification were effective modifications to produce a pea flour ingredient with enhanced SDS and RS content.     

Extrusion Properties and Cooking Quality of Spaghetti Containing Buckwheat Bran Flour

The effect of hydration level on processing properties and the effects of hydration level, concentration of buckwheat bran flour and drying temperature on the physical and cooking quality of spaghetti were determined. Specific mechanical energy transferred to the dough during extrusion decreased 69% for semolina and 79% for semolina containing 30%, w/w, buckwheat bran flour, as hydration level increased 29–32% absorption. Little or no postdrier checking occurred in spaghetti made from semolina or spaghetti containing buckwheat bran flour when dried at high (70°C) or ultrahigh temperature (90°C). When dried at low temperature (40°C), tolerance to postdrier checking of spaghetti decreased as buckwheat bran flour increased 0–30% (w/w). Hydration level before extrusion did not affect cooking loss of spaghetti made from semolina. However, cooking loss was greater from spaghetti made with semolinabuckwheat bran flour that was hydrated to 32% compared with 29–31% absorption. Cooked firmness of spaghetti containing buckwheat bran flour decreased from 0.588–0.471 Nm as hydration increased from 29–32% absorption. Cooking loss was lower and cooked firmness was greater when spaghetti containing buckwheat bran flour was dried at ultrahigh than at low temperature.     

Quality and Fortificant Retention of Rice Noodles as Affected by Flour Particle Size

Rice noodles, which are widely consumed noodles in Southeast Asia, were evaluated as a potential carrier for fortificants such as vitamin A, folic acid, and iron. Because flour particle size was found to affect the noodle properties, this study was conducted to investigate the effect of five different particle sizes (≤63, 80, 100, 125, and 140 µm) of dry‐milled rice flour on the cooking quality, microstructure, texture, and sensory characteristics of the rice noodles. The retention of fortificant in the noodles at every stage of processing as affected by the flour particle size was also determined. It was found that the rice noodles produced from flour with the smallest particle size studied (≤63 µm) had the best quality and were the most liked by the consumers. In addition, the noodles had the most compact and regular structure, which could be attributed to having the most severely gelatinized starch. This starch would have caused the least leaching of the fortificant into the surrounding water during the boiling stage of the rice noodle processing. Retention of iron in the cooked fortified rice noodles prepared from flour with the smallest particle size was high at around 87%, whereas that of vitamin A and folic acid were below 15%. Because the losses of the fortificant from the rice noodles were mostly owing to the boiling process, further improvements of the rice noodle processing conditions are required for reduction of the vitamin losses.     

Functional and Digestive Characteristics of Extruded Rice Flour

Waxy (short grain), long grain, and parboiled (long grain) rice flours were extruded using three different temperatures and five different water feed rates. The water absorption and water solubility index of the extrudates was 0.67–5.86 and 86.45–10.03%, respectively. The fat absorption index was similar to that of unextruded flours with an average value of 0.96 g/g ± 0.12. Bulk density decreased with an increase in moisture, except waxy rice, which had a quadratic relationship. The viscosity profiles for long grain and parboiled rice were similar. Both initially increased in viscosity (>130 RVU), then decreased to ≈40 RVU. The final viscosity was ≈60 RVU. Waxy rice viscosity remained low (<20 RVU), then doubled upon cooling. The main difference in the digestion profiles was due to temperature. The flours extruded at 100°C digested significantly slower than those extruded at 125 and 150°C. Significant differences were not detected for a given temperature and moisture (P > 0.05) except for long grain and parboiled rice extruded at 100°C and 15% added moisture (F = 4.48, P = 0.03) and 150°C and 20% added moisture (F = 3.72, P = 0.05). Moisture appeared to have little effect for a given temperature, except when parboiled rice was extruded at 150°C. The digestion rate for 11 and 25% added moisture was significantly less than that for 20% (P ≤ 0.05).     

Effects of Flour Particle Size and Starch Damage on Processing and Quality of White Salted Noodles

Several reduction grinding conditions were used on a Canadian Western Red Spring (CWRS) farina to yield flours of comparable protein content within three specific particle size ranges (132–193, 110–132, 85–110 μm) at three starch damage levels (3.0, 3.9, 7.0 Megazyme units). White salted noodles (1% w/w NaCl) were initially processed at a fixed absorption (32%). Dynamic oscillatory and large deformation creep measurements indicated that doughs with lower starch damage, thick or thin, exhibited lower G′ (storage modulus), higher tan δ (G″ [loss modulus]/G′) values, and greater maximum strain during creep than doughs with higher starch damage. There were no clear trends between work input during sheeting and either starch damage or particle size. Instrumental texture analysis of raw noodles showed no significant differences due to either starch damage or flour particle size. Flours with fine particle size gave cooked noodles with the best textural attributes, whereas starch damage exhibited no consistent relationship with cooked noodle texture. Cooking loss was greatest in samples with highest starch damage and coarsest particle size; water uptake was inversely related to starch damage and particle size. Experiments were repeated at adjusted water absorptions (32–36.5%) for fine and coarse flours with highest and lowest starch damage. Differences in raw noodle dough rheological properties were largely eliminated, confirming that differences noted at constant absorption were primarily due to flour water absorption. Work input during sheeting was inversely related to starch damage and was higher for fine particle size. Cooking losses were highest for higher starch damage and fine particle size. Water uptake was highest for fine particle size, but in contrast to cooking loss, was higher at lower starch damage. Textural parameters indicated superior cooking quality when particle size was finer and starch damage was lower. Flour particle size and starch damage (as indicated by water absorption) are both primary quality determinants of white salted noodle properties and, to some extent, exert their influence independently.     

Effects of Milling and Cooking Conditions of Rice on In Vitro Starch Digestibility and Blood Glucose Response

The objective of this study was to investigate the effects of milling and cooking conditions of cooked rice prepared from cultivar Koshihikari on in vitro starch digestibility and in vivo glucose response in humans. In addition, compression and adhesiveness tests were conducted for texture analysis of the cooked rice. Brown rice (BR) and surface‐abraded BR (SABR, ≥99.5% of the original weight) were digested more slowly than white rice (91% of the original weight) when cooked rice grain was used for the in vitro test, but they were digested more rapidly in the initial stage of the reaction when cooked rice ground by a meat grinder was used. The increase in water added for cooking significantly increased the extent of starch digestion with BR and SABR. The changes in blood glucose levels after the ingestion of cooked rice were dependent on the sample type. The cooking conditions dramatically influenced the glucose response after the ingestion of BR. A significant correlation was found between blood glucose levels at 45 min and the extent of starch digestion with ground samples, whereas no relationship was found with cooked rice grain samples for in vitro digestibility.     

Relationship Between Grain,Semolina, and Whole Wheat Flour Properties and the Physical and Cooking Qualities of Whole Wheat Spaghetti

Durum breeding programs need to identify raw material traits capable of predicting whole wheat spaghetti quality. Nineteen durum wheat (Triticum turgidum L. var. durum ) cultivars and 17 breeding lines were collected from 19 different environments in North Dakota and were evaluated for physical and cooking qualities of whole wheat spaghetti. Raw material traits evaluated included grain, semolina, and whole wheat flour characteristics. Similar to traditional spaghetti, grain protein content had a significant positive correlation with cooking quality of whole wheat spaghetti. Stepwise multiple regressions showed grain protein content, mixogram break time, and wet gluten were the predominant characteristics in predicting cooked firmness of whole wheat spaghetti.