Effect of Elevated Carbon Dioxide Concentration on Rice Quality: Proximate Composition,Dietary Fibers,and Free Sugars

Little is known regarding the impact of elevated carbon dioxide concentration ([CO₂]) on the chemical composition of rice grains. A field experiment was conducted with open‐top chambers with rice (Oryza sativa L. cv. Ariete) grown at two levels of atmospheric CO₂ (375 and 550 μmol/mol), and their effects were monitored on the proximate composition and carbohydrate contents of the grains. Following exposure to elevated [CO₂], soluble dietary fiber increased by 136, 82, and 77% in brown rice, white rice, and bran, respectively. Increases of a lower magnitude (8%) were observed for insoluble dietary fiber in the bran and brown rice. For all 10 sugars identified, there was a trend for increasing their content. For example, increases of 135% were recorded for glucose in the white rice. In all rice milling fractions, elevated [CO₂] reduced the protein (4–15%) and amylose (6–16%) contents, with no effect on the ash, starch, and gross energy contents. The fat content was increased by elevated [CO₂] in the white rice (23%) and tended to decrease in the bran (9%). It is concluded that besides yield, increased dietary fiber might be another positive effect of high levels of atmospheric CO₂ expected by the middle of the current century.     

Chemical and Physical Characteristics of Proso Millet (Panicum miliaceum)‐Based Products

Celiac disease and gluten sensitivities, as well as obesity and overweight‐related disorders, have led to the investigation of gluten‐free grains and development of new food products. To address this, refined proso millet and refined corn (control), both gluten‐free grains, were used to produce four different product types (muffin, couscous, extruded snack, and porridge). The products contained four different grain combinations (100% proso millet, 75% proso millet/25% corn, 25% proso millet/75% corn, and 100% corn). All products were evaluated for their nutritional composition, in vitro starch digestibility, and expected glycemic index (eGI). Products made with refined proso millet had increased protein (7.6–11.3%), lipid (1.2–6.1%), fiber (7.0–8.8%), and phenolic content (323.5–425 μg/g) compared with those incorporating corn flour (2.5–9.0%, 0.8–4.0%, 2.1–4.1%, and 213–315 μg/g, respectively). As the proso millet content increased, the eGI decreased significantly (P < 0.05). Products made from refined proso millet appear to be good candidates for producing low‐GI, gluten‐free foods.     

Lipidemic Response of Hamsters to Rice Bran,Uncooked or Processed White and Brown Rice,and Processed Corn Starch

This study was undertaken to evaluate the lipidemic response of rice bran and the possible enhancement of its healthful properties by using raw or processed white or brown rice in place of corn starch. All diets contained 10% total dietary fiber, 15% fat, and 0.5% cholesterol. Weanling male golden Syrian hamsters were fed cellulose control (CC), processed corn starch (PCS), cellulose with processed brown rice (CPBR), rice bran (RB), RB with white rice (RBWR), RB with processed white rice (RBPWR), RB with brown rice (RBBR), and RB with processed brown rice (RBPBR) diets. After three weeks, the PCS diet significantly lowered total plasma cholesterol (TC) compared with the CC, CPBR, RBWR, and RBPBR diets. RB and RBBR diets significantly lowered TC and LDL‐C compared with CPBR diet. All the RB‐containing and PCS diets significantly lowered liver cholesterol and liver lipid content. Processing white rice increased TDF content 240% and insoluble dietary fiber (IDF) 360%, whereas soluble dietary fiber (SDF) decreased by 25%. Uncooked brown rice contained 7 times as much TDF as uncooked white rice. Processing brown rice decreased its TDF, IDF and SDF contents by 12, 6, and 42%, respectively. The data suggest that a possible mechanism for cholesterol‐lowering by rice bran, with or without added raw or processed rice (white or brown), is by decreasing lipid digestibility and increasing neutral sterol excretion, whereas cholesterol‐lowering by processed corn starch is mediated through other mechanisms.     

Yield and Phytosterol Composition of Oil Extracted from Grain Sorghum and Its Wet‐Milled Fractions

Corn fiber contains an oil with high levels of three potential cholesterol‐lowering phytosterol compounds. Little information is available about the levels and types of phytosterols in sorghum. In this study, phytosterols were evaluated in grain sorhgum and its wet‐milled fractions and were compared with the phytosterols in corn. The study showed that sorghum kernels can provide a significant source of two phytosterol classes, free phytosterols (St) and fatty acyl phytosterol esters (St:E). Most of these phytosterols are concentrated in the wet‐milled fiber fraction followed by the germ fraction. In addition to phytosterols, other lipid classes such as wax esters and an aldehyde (50% C28 and 50% C30) are also present in the sorghum oil. Comparison of sorghum and corn kernels show that corn has 72–93% more phytosterols than sorghum.     

In Vitro Bile‐Acid‐Binding of Whole vs. Pearled Wheat Grain

Health benefits of consuming whole grains are reduced risk of heart disease, stroke, and cancer. The U.S. Health and Human Services and USDA dietary guidelines recommend consumption of 6–10 oz of grain products daily and one‐half of that amount should contain whole grains. Whole grains contain vitamins, minerals, fiber, and phytonutrients. Bile‐acid‐binding capacity has been related to cholesterol lowering potential of food fractions. Lowered recirculating bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile‐acid‐binding potential has been related to lowering the risk of heart disease and that of cancer. It has been reported that bile‐acid‐binding of wheat bran is not related to its total dietary fiber (TDF) content. Whole (W) grain as well as pearled (P) hard red winter wheat (Hrw), hard white winter wheat (Hww), and durum wheat (DU) cooked grains were evaluated for in vitro, bile‐acid‐binding relative to cholestryramine (a cholesterol lowering bile‐acid‐binding drug). On dry matter basis (db) relative bile‐acid‐binding values were 7.7% WHrw; 7.5% WHww; 6.3% PHww; 6.0% PHrw; 5.5% WDU; and 5.4% PDU. On a TDF basis, binding values were 42–57% of that for cholestyramine for the whole and pearled wheat grains tested. Bile‐acid‐binding values (db) for WHrw and WHww were similar and significantly higher than those of PHww, PHrw, WDU and PDU. Similar bile‐acid‐binding of WHww to that of WHrw suggest that the red color commonly associated with whole grain may not necessarily indicate more healthful potential. Data suggest that cooked WHrw and WHww wheat have significantly higher health‐promoting potential than pearled grains. WDU or PDU wheat health‐promoting potential was similar to that of PHww or PHrw. Consumption of products containing WHrw and WHww are recommended.     

Hybrid Variability and Effect of Growth Location on Corn Fiber Yields and Corn Fiber Oil Composition

The variability in commercial corn hybrids for corn fiber yields, amounts of extractable oil, and levels of individual and total phytosterol components in corn fiber oil was determined. Also, the effect of growth location on fiber yields, fiber oil content, and the levels of individual and total phytosterol compounds was determined. Significant variation was observed in the commercial hybrids for fiber yield (13.2–16.6%) and fiber oil yield (0.9–2.4%). No significant correlation was observed between fiber and oil yields. Significant variations in the commercial corn hybrids were also observed in the individual phytosterol compounds in corn fiber oil: 2.9–9.2% for ferulate phytosterol esters (FPE); 1.9–4.3% for free phytosterols (St); and 6.5–9.5% for phytosterol fatty acyl esters (St:E). Positive correlations were observed among the three phytosterol compounds in the corn fiber oil (R = 0.75 for FPE and St:E; 0.48 for St:E and St; and 0.68 for FPE and St). The effect of location on dependent variables was also significant. The same hybrids grown at different locations showed a variation (range) of 4.0–17.5% for FPE, 4.9–12.2% for St:E, and 1.95–4.45% for St. Relative ranking of hybrids with respect to phytosterol composition was consistent for almost all of the growth locations.     

Compliance with Gluten‐Free Labelling Regulation in the Brazilian Food Industry

Gluten is an important protein complex for baking products found in wheat, rye, barley, and some oat varieties. However, some people need to avoid these grains and their products because they result in gluten‐related disorders. The only treatment for these individuals is to engage in a gluten‐free diet. The objective of this work was to verify if the gluten content of several commercial food products sold in Brazil complied with their labeling. The Méndez ELISA R5 sandwich method was used to analyze 437 samples, and of these, 70% were labeled as gluten‐free, 26% as containing gluten, and 4% not labeled in relation to gluten. The results indicated that 89% of the products labeled as gluten‐free were correctly labeled and 11% were not, which represented a risk for celiac people.     

Chemical Constituents,Dietary Fiber,and γ‐Oryzanol in Six Commercial Varieties of Brown Rice from Taiwan

In the interest of promoting the consumption of whole grains, the chemical constituents (moisture, protein, ash, and fat) and biofunctional components (dietary fiber and γ‐oryzanol) were determined in six varieties of brown rice (five japonica and one indica) that are preferred in the form of polished rice by consumers in Taiwan. The results showed significant differences (P < 0.05) in the chemical compositions of the samples for all the measured parameters. The Koshihikari variety had the highest contents of protein and crude ash. Crop year showed significant effects on the moisture content and partly on the protein, ash, and fat contents. The total dietary fiber content of the tested rice ranged between 5.1 and 10.0%, with Kaohsiung 145 having the highest content (P < 0.05). In all varieties, the content of insoluble dietary fiber was greater than that of soluble dietary fiber. The content (mg/100 g) of γ‐oryzanol ranged from 17.9 to 29.2 for the 2009 crop and from 24.5 to 41.3 for the 2010 crop. It showed that γ‐oryzanol was affected by crop year and variety. The japonica types had significantly higher γ‐oryzanol content (P < 0.05) than the indica type. Taikeng 9 and Tainan 11 had greater γ‐oryzanol content than the other rice varieties.     

Opportunities and Challenges in Processing of By‐product of Rice Milling Protein as a Food Ingredient

The by‐product of rice milling (BRM), known as commercial rice bran, is the coproduct of rice processing. It is a mixture of outer layers of the grain, the embryo, and some of the starchy endosperm, and these are separated from brown rice to produce white, milled rice. This mixture contains a high concentration of protein (12–20%) in comparison with that of brown rice (7.1–8.3%) or white rice (6.3–7.1%) and is therefore an abundant and cheap protein source. Nearly 70% of the proteins in BRM are albumins and globulins, which are high in solubility, digestibility, and nutritional value. The BRM proteins are hypoallergenic and gluten‐free. With these properties, this type protein has many advantages as a unique and valuable protein source in markets such as protein supplements. The BRM protein can be extracted by physical, alkali, and enzymatic methods, which give yields ranging from 13% to more than 90%. This review highlights the opportunities and challenges in processing of BRM protein as a food ingredient.     

Effects of Chinese and North American Wild Rice on Blood Lipids,Oxidative Stress,and Inflammation Factors in Hyperlipidemic Rats

The aim of the present study was to compare the effects of replacing processed rice and wheat starch with Chinese and North American wild rice as the chief source of dietary carbohydrates in rats fed high levels of saturated fat and cholesterol. The study consisted of five groups: low‐fat diet, high fat/cholesterol diet, city diet, North American wild rice diet, and Chinese wild rice diet. At the end of eight weeks of the diet regimen, the North American and Chinese wild rice diets suppressed the increase in serum triglyceride and total cholesterol but also decreased the high‐density lipoprotein cholesterol level. In addition, rats fed either the North American or Chinese wild rice diet suppressed the build‐up of oxidative stress by improving total antioxidant capacity, increasing superoxide dismutase activity, and reducing malondialdehyde concentration. In contrast, rats fed with the high fat/cholesterol diet and city diet had increased concentrations of high‐sensitivity C‐reactive protein (hs‐CRP) and tumor necrosis factor α (TNF‐α) compared with the low‐fat diet; rats fed with the Chinese wild rice diet had a significantly decreased serum hs‐CRP protein and TNF‐α concentration. Higher serum hs‐CRP levels were verified in the city diet group compared with North American wild rice diet group. These findings illustrate that both North American wild rice and Chinese wild rice are effective in suppressing hyperlipidemia, oxidative stress, and inflammation in rats even when the diet consumed is high in fat and cholesterol.     

Phosphorus and Mineral Concentrations in Whole Grain and Milled Low Phytic Acid (lpa) 1‐1 Rice

Phytic acid (myo‐inositol‐1,2,3,4,5,6‐hexakisphosphate) is the most abundant form of phosphorus (P) in cereal grains and is important to grain nutritional quality. In mature rice (Oryza sativa L.) grains, the bulk of phytic acid P is found in the germ and aleurone layer, deposited primarily as a mixed K/Mg salt. Phosphorus components and minerals were measured in whole grain produced by either the rice (Oryza sativa L.) cv. Kaybonnet (the nonmutant control) or the low phytic acid 1‐1 (lpa1‐1) mutant, and in these grains when milled to different degrees (10, 12, 17, 20, 22, and 25%, w/w). Phytic acid P is reduced by 42–45% in lpa1‐1 whole grain as compared with Kaybonnet, but these whole grains had similar levels of total P, Ca, Fe, K, Mg, Mn, and Zn. In both genotypes, the concentration of phytic acid P, total P, Ca, Fe, K, Mg, and Mn in the milled products was reduced by 60–90%, as compared with whole grain. However, a trend was observed for higher (25–40%) total P, K, and Mg concentrations in lpa1‐1 milled products as compared with Kaybonnet milled products. The reduction in whole grain phytic acid P in rice lpa1‐1 is accompanied by a 5‐ to 10‐fold increase in grain inorganic P, and this increase was observed in both whole grain and milled products. Phytic acid P was also reduced by 45% in bran obtained from lpa1‐1 grain, and this was accompanied by a 10‐fold increase in inorganic P. Milling had no apparent effect on Zn concentration. Therefore, while the block in the accumulation of phytic acid in lpa1‐1 seed has little effect on whole grain total P and mineral concentration, it greatly alters the chemistry of these seed constituents, and to a lesser but detectable extent, alters their distribution between germ, central endosperm, and aleurone. These studies suggest that development of a low phytate rice might improve the nutritional quality of whole grain, milled rice and the bran produced during milling.     

Formation of Oligosaccharides and Polysaccharides by Lactobacillus reuteri LTH5448 and Weissella cibaria 10M in Sorghum Sourdoughs

Gluten‐free breads, which are composed of gluten‐free flours, starch, and hydrocolloids, differ from wheat and rye breads in relation to texture, volume, and crumb structure. Moreover, the dietary fiber content is lower compared with wheat or rye breads. Cereal isolates of lactic acid bacteria frequently produce oligo‐ and homopolysaccharides from sucrose, which can improve the nutritional and technological properties of gluten‐free breads as prebiotic carbohydrates and hydrocolloids, respectively. Sorghum sourdough was fermented with Lactobacillus reuteri LTH5448 or Weissella cibaria 10M, which synthesize fructooligosaccharides (FOS) and levan, and isomaltooligosaccharides and dextran, respectively. The gluten‐free bread was produced with 14% sourdough addition. L. reuteri LTH5448 formed FOS and 1.5 g of levan/kg DM in quinoa sourdoughs. FOS were digested by the baker's yeast during proofing, and the levan could be qualitatively detected in the bread. W. cibaria 10M produced >60 g of isomaltooligosaccharides/kg DM and 0.6 g of dextran/kg DM, which could still be detected in the bread. Breads prepared with W. cibaria 10M were less firm compared with breads prepared with L. reuteri LTH5448 or a FOS and levan‐negative mutant of L. reuteri LTH5448. The addition of sourdoughs fermented with oligo‐ and polysaccharide forming starter cultures can increase the content of prebiotic oligosaccharides in gluten‐free breads.     

Metabolic Responses to Venezuelan Corn Meal and Rice Bran Supplemented Arepas (Breads)

The metabolic responses to South American foods remain to be determined. Using glycemic index (GI) and insulinemic index (II) values as references for therapeutic potential of foods, this study investigated the glucose responses to a typical Venezuelan corn bread (arepa) and to an arepa supplemented with rice bran. Adding rice bran to the bread increased the content of resistant starch and dietary fiber measured as total, soluble, and insoluble dietary fiber. It also increased the protein content of the arepa. Three meals, white wheat bread, 100% corn meal arepa, and an arepa supplemented with 20% rice bran, were administered within a one‐week period. Available starch in the foods was determined to provide 50 g of available carbohydrate per meal. To calculate the indices, bread was used as the reference. The GI and II of the two arepa meals were significantly smaller than the GI and II of white wheat bread, although the differences between the two types of arepas were not significant. It is concluded that Venezuelan arepas (corn meal bread) may have potential health benefits and that the presence of 20% rice bran in the arepa meal did not produce a significant improvement in the glucose response. Due to the presence of antioxidant elements in the supplemented arepa and its higher protein, dietary fiber, and resistant starch content, it may have a potential preventive effect against the development of other pathologies.     

Textural Comparisons of Gluten‐Free and Wheat‐Based Doughs,Batters, and Breads

Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.     

Promoting Cereal Grain and Whole Grain Consumption: An Australian Perspective

Go Grains Health & Nutrition encourages consumption of grain‐based foods in Australia through activities that promote awareness and understanding of the role of grain foods in a healthy diet. Strategies drive the message of the Australian dietary guidelines that a healthy diet should include at least four servings of grain‐based foods every day (1 serving is equal to two slices of bread). The “Go Grains 4+ Serves a Day” program promotes grain‐based foods (refined and whole grain) through the media, website information, resource development, school education, and food industry involvement. Interest in whole grains is growing, reflected in a shift in bread sales over recent years from white to whole grain. Manufacturers are responding with new and reformulated whole grain product launches and an increasing number of products carry packaging statements about whole grain content. Australian food regulations do not permit health claims in packaging or in advertising. In the absence of official guidelines, Go Grains has developed a whole grain daily target intake for use by food manufacturers in packaging. There are limited data publicly available to describe consumption of grain‐based foods in Australia. The findings of a 2009 survey commissioned by Go Grains help provide insight into consumption trends.     

Laboratory Procedure to Wet‐Mill 100 g of Grain Sorghum into Six Fractions

A small‐scale (100 g of grain) procedure was developed to wet‐mill grain sorghum into six fractions by modifying the procedure of Eckhoff et al (1996). The wet‐milling process was repeated five times on commercial grain sorghum, and the mean yield (69.4%) of starch (≤0.3% protein) varied by 0.3%, whereas the yields of fiber, gluten, and germ plus bran fractions varied by 5–6%. The starch fraction accounted for ≈95% of that in the grain, while the total solids recovered was 99.0%. Four other samples of grain sorghum gave 92–95% recoveries of starches and 98.2–99.8% recoveries of total solids. All grain sorghum starches had lightness (L*) values and pasting curves nearly equal to those of a commercial maize starch.     

Pretreatment of Wet‐Milled Corn Fiber to Improve Recovery of Corn Fiber Oil and Phytosterols

The phytosterol‐containing oil in the corn fiber (corn fiber oil) has potential use as a natural low‐density lipoprotein (LDL) lowering nutraceutical but its low concentration (1–3%) makes it difficult and expensive to extract. Pretreatment of corn fiber with dilute acid or glucosidases removed nonlipid components of fiber, producing oil‐enriched fractions that should be more amenable to efficient and inexpensive oil extraction. Acid, as well as enzymes, significantly increased the content of corn fiber oil and its phytosterol compounds by hydrolyzing (and removing) the starch and nonstarch (cell wall) polysaccharides from the wet‐milled corn fiber. Dual treatment of the fiber with acid and enzyme greatly increased the concentrations of corn fiber oil and its phytosterol components, compared with acid or enzyme treatments alone. Depending on the treatment, the oil concentration in the residual solids increased from 0.3 to 10.8% (21–771% increase in conc.) and the total phytosterol concentration increased from 19.8 to 1256.2 mg/g of fiber (11–710% increase in conc.) compared with untreated fiber.     

REVIEW: Effects of Germination on the Nutritional Profile of Gluten‐Free Cereals and Pseudocereals: A Review

There are a growing number of individuals diagnosed with food allergies and intolerances. Gluten, in particular, is avoided by many individuals because of celiac disease, gluten intolerance, and gluten ataxia. Individuals with allergies, intolerances, or both follow strict diets, but there is concern that these individuals may be at risk of several nutrient deficiencies, including decreased calcium, iron, B vitamins, and fiber. To prevent deficiencies, alternative sources of these nutrients must be provided. Gluten‐free cereals and pseudocereals such as amaranth, buckwheat, corn, millet, rice, sorghum, and quinoa can be excellent sources of vitamins, minerals, fiber, and other important nutrients. Germination of these edible seeds has been shown to further increase nutrient content and to reduce antinutrients. Their use to naturally fortify and enrich gluten‐free foods has great potential. Although there are many benefits to germinated seeds in food, more research must be done to improve texture and sensory properties to gain wider consumer acceptance. A review of germination of gluten‐free cereals and pseudocereals and its effect on their nutritional profile is presented.     

Sinapate dehydrodimers and sinapate-ferulate heterodimers in cereal dietary fiber

Two 8-8-coupled sinapic acid dehydrodimers and at least three sinapate-ferulate heterodimers have been identified as saponification products from different insoluble and soluble cereal grain dietary fibers. The two 8-8-disinapates were authenticated by comparison of their GC retention times and mass spectra with authentic dehydrodimers synthesized from methyl or ethyl sinapate using two different single-electron metal oxidant systems. The highest amounts (481 microg/g) were found in wild rice insoluble dietary fiber. Model reactions showed that it is unlikely that the dehydrodisinapates detected are artifacts formed from free sinapic acid during the saponification procedure. The dehydrodisinapates presumably derive from radical coupling of sinapate-polymer esters in the cell wall; the radical coupling origin is further confirmed by finding 8-8 and 8-5 (and possibly 8-O-4) sinapate-ferulate cross-products. Sinapates therefore appear to have an analogous role to ferulates in cross-linking polysaccharides in cereal grains and presumably grass cell walls in general.     

Network Formation in Gluten‐Free Bread with Application of Transglutaminase

One of the main problems associated with gluten‐free bread is obtaining a good structure. Transglutaminase (TGase), an enzyme that catalyzes acyl‐transfer reactions through which proteins can be cross‐linked could be a way to improve the structure of gluten‐free breads. The objective of this study was to evaluate the impact of TGase at different levels (0, 0.1, 1, and 10 U of TGase/g of protein) on the quality of gluten‐free bread. The recipe consisted of white rice flour (relative amount: 35), potato starch (30), corn flour (22.5), xanthan gum (1), and various protein sources (skim milk powder [SMP] [12.5], soya flour, and egg powder). The influence of the various proteins in combination with the different addition levels of TGase on bread quality (% bake loss, specific volume, color, texture, image characteristics, and total moisture) was determined. Confocal laser‐scanning microscopy (CLSM) was used to evaluate the influence of TGase on the microstructure of the bread. Baking tests showed that TGase had an effect on the specific volume of the bread. For instance, the SMP bread with 10 U of enzyme contained the most compact structure, which was reflected in the crumb texture profile analysis results (highest values) (P < 0.05), digital image analysis (highest level of cells/cm²) (P < 0.05), and CLSM micrographs (network formation). Finally, it can be concluded that it is possible to form a protein network in gluten‐free bread with the addition of TGase. However the efficiency of the enzyme is dependent on both the protein source and the level of enzyme concentration.