Salt Stress Induces Accumulation of γ–Aminobutyric Acid in Germinated Foxtail Millet (Setaria italica L.)

Effects of NaCl treatments on sprout length, the contents of soluble protein, free amino acids, and γ‐aminobutyric acid (GABA) and on glutamate decarboxylase (GAD) activity in germinated foxtail millet were investigated, and the regulating effects of exogenous Ca²⁺, along with lanthanum chloride (LaCl₃, a specific inhibitor of the Ca²⁺ pathway) and ethylene glycol tetraacetic acid (EGTA, a chelator of Ca²⁺) under salt stress, on GABA accumulation in germinated millet were examined in this paper. The results showed that NaCl treatments caused a decrease in sprout length of millet. Low concentration of NaCl treatments increased soluble protein content, but high concentration decreased soluble protein content. The level of free amino acids, GAD activity, and GABA content increased significantly under NaCl stress. Exogenous Ca²⁺ application under NaCl stress further increased GAD activity and GABA content; the optimal concentration of Ca²⁺ for GAD activity and GABA accumulation was 5.0mM under 100mM NaCl for 48 hr, at which GABA content was 31.92 mg/100 g, a 1.41‐fold increase as compared with that in seeds under NaCl stress (22.64 mg/100 g). GAD activity and GABA accumulation in germinated millet decreased when treated with LaCl₃ or EGTA under NaCl stress. Our results suggest that salt stress combined with Ca²⁺ treatment may be used for preparation of millet with higher GABA content, which can be used as a natural resource for functional foods.     

提高发芽糙米得率的复合酶预处理工艺优化

为解决传统工艺生产发芽糙米浸泡时间长、生产效率低等问题,提出以纤维素酶和木聚糖酶的复合溶液代替蒸馏水浸泡发芽前糙米的新工艺。以糙米为原料,探究复合酶预处理工艺中酶解时间、酶解温度、复合酶浓度及配比对发芽糙米得率的影响规律,采用二次正交旋转中心组合设计试验,建立了各因素对发芽糙米得率影响的数学模型。结果表明:酶解时间、酶解温度、复合酶浓度及酶配比对发芽糙米得率影响显著(P0.05),得到优化参数组合为:酶解时间135 min,酶解温度35℃,复合酶浓度0.57 g/L、纤维素酶和木聚糖酶质量比1.86:1,在此条件下,与传统工艺相比浸泡时间缩短62.5%、发芽糙米得率及γ-氨基丁酸含量分别提高约3.90%和3.86 mg/(100 g)。通过对酶解后糙米皮层微观结构的观察分析,糙米皮层在复合酶作用下部分降解,胚乳中淀粉更易与水分子相结合,从而吸水速率提升。研究结果可为发芽糙米生产提供参考。     

Rapid Prediction of Rice Quality Characteristics by Near‐Infrared Reflectance Spectroscopy for Breeding Programs

Breeding of high‐quality rice requires quick methods to evaluate the quality characteristics such as milling, grain appearance, nutritional, eating, and cooking qualities. Because routine measurements of these quality traits are time consuming and expensive, a rapid predictive method based on near‐infrared spectroscopy (NIRS) can be applied to measure these quality parameters. In this study, calibration models for measurement of grain quality were developed using a total of 570 brown and milled rice samples. The results indicated that the models developed from the spectra of brown rice for all the quality traits had the coefficient of determination for external validation (R²) larger than 0.64 except for gel consistency. The best model was developed for the protein content, with R² of 0.94 for external validation. The model for the total score of physicochemical characteristics (TSPC), a comprehensive index reflecting all other traits, had R² of 0.70 and SD/SEP of 1.70, which indicates that high or low TSPC for a given rice could be discriminated by NIRS. The models developed from brown rice were as accurate as those from milled rice. Results suggest that NIRS‐based predictions for rice quality traits may be used as indicator traits to improve rice quality in breeding programs.     

锌离子活度对水稻产量及子粒锌含量的影响及基因型差异

试验采用HEDTA螯合缓冲营养液培养法,选用子粒含锌量有明显差异的两个水稻基因型(碧玉早糯和浙农921),采用4种锌离子活度(pZn2+9.7,10.3,11.0,11.4),研究了锌离子活度对水稻产量和子粒锌积累、分配与子粒品质的影响及基因型差异。结果表明,锌离子活度通过对水稻有效穗数、每穗颖花数、结实率和千粒重的影响而显著影响水稻单株产量,其中影响最大的是单株有效穗数,其次是每穗颖花数,而对结实率的影响相对较小,但均存在明显的基因型差异。锌离子活度显著影响水稻子粒锌含量,随锌离子活度下降,水稻子粒含锌量降低,当锌离子活度低于pZn2+10.3时,两基因型水稻的含锌量均显著降低,但基因型间存在明显差异。不论在何种锌离子活度下,碧玉早糯的子粒含锌量均显著高于浙农921。从子粒锌分配看,颖壳、糙米、精米锌含量均随着锌离子活度提高而提高,当pZn2+从10.3升高到9.7时,碧玉早糯的糙米和精米锌含量开始降低,颖壳锌含量则开始超过糙米的锌含量继续升高;而浙农921糙米和精米锌含量的升高幅度较颖壳锌含量小。不同锌离子活度下,糙米和精米锌含量的比值在0.790~.90之间变化,并以pZn2+为9.7时为最小。因此,通过筛选子粒富锌水稻品种来提高稻米锌含量经济可行;通过增加环境锌离子活度,改善水稻的锌营养能显著提高水稻子粒的锌含量。     

Genotypic variation in grain cadmium concentration of lowland rice

Cadmium (Cd) contamination of paddy rice soils is commonly observed in the Yangtse River Delta, China. Large Cd uptake by rice plants and its translocation into the grains can entail human‐health risks. Genotypic variations in Cd uptake and a differential Cd partitioning into grains will be the basis for developing a rice screening or breeding tool for low grain Cd. A field experiment, conducted at the experimental farm of Jiaxing, Zhejiang province from 2002 to 2004, compared 38 rice genotypes of different types (indica vs. japonica) collected from the Yangtse River Delta. The results showed large differences in Cd concentrations in straw, brown rice, and grain chaff among the rice genotypes grown on Cd‐contaminated soil. Concentrations in brown rice ranged from 0.06 to 0.99 mg Cd kg^–1. The total Cd uptake in brown rice varied between 0.96 and 28.58 μg plant ^{– 1}. In general, indica‐type cultivars accumulated significantly more Cd than the japonica‐type cultivars. The Cd concentration in straw was highly correlated with that in brown rice. While significant differences in the Cd‐partitioning ratio (% share of total Cd uptake found in brown rice) among rice genotypes were observed, these were not correlated with Cd concentration of brown rice. This indicates that the Cd accumulation in rice grains appears to be governed mainly by the Cd uptake by the plant and probably not by differential Cd partitioning. The large genotypic variation suggests the possibility to lower the Cd content of rice by genotype selection. The development of such breeding tools should focus on low Cd uptake rather than Cd partitioning between straw and grain.     

Genotypic variation in grain mercury accumulation of lowland rice

A pot experiment with 38 commonly cultivated rice cultivars from the Yangtze River Delta was conducted in a greenhouse to study the effect of mercury (Hg) contamination of a paddy soil (4.7 mg Hg [kg soil]^–1) on crop growth and Hg accumulation in the grains. Mercury contamination differentially affected growth, grain yield, and Hg accumulation in brown rice of the tested cultivars. The average Hg concentration in the grains was significantly higher (p < 0.01) when plants were grown in the Hg‐contaminated compared to the control soil. Averaged over cultivars, the Hg concentration in brown rice exceeded the maximum permissible limit of 20 μg Hg kg^–1. Increasing Hg concentrations were associated with grain‐yield declines up to 70%. This yield decline was mainly due to a reduction in the number of panicles. Japonica cultivars tended to be generally less affected by Hg than indica cultivars. The two japonica cultivars Jiahua and Chunjiang 026 showed both low Hg concentrations and no Hg‐induced grain‐yield reduction. These cultivars may be preferred candidates for cultivation in Hg‐contaminated soils or for studies on possible Hg‐exclusion mechanisms.     

Storage Stability of Flour‐Blasted Brown Rice

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 texture (hardness, gumminess) and water absorption. The combined coefficient of correlation (including all types of rice) between FFA and FV is r = 0.86 and between FFA and SB is r = 0.90 at P < 0.0001.     

Quantitative Analysis of Fat Content in Rice by Near‐Infrared Spectroscopy Technique

Fat content in rice is one of the most important nutritional quality properties. But the chemical analysis of fat content is time‐consuming and costly and could result in poor reproduction between replicates. Near‐infrared spectroscopy (NIRS) can solve those problems by providing a rapid, nondestructive, and quantitative analysis. Based on the NIRS technique and partial least squares (PLS) algorithm, four calibration models were established to quantitatively analyze fat content in brown rice grain and flour and milled rice grain and flour with 248 representative samples. The determination coefficients (R²) of these calibration models were 0.79, 0.84, 0.89, and 0.91, respectively, with the corresponding root mean square errors 0.16, 0.14, 0.09, and 0.08%. The R² were 0.73, 0.81, 0.81, and 0.89 with the corresponding root mean square errors 0.17, 0.15, 0.12, and 0.09%, respectively, in cross validation. The R² were 0.62, 0.80, 0.81, and 0.87, respectively, with the root mean square errors 0.25, 0.31, 0.28, and 0.30% in external validation. These results indicate that the method of NIRS has relatively high accuracy in the prediction of rice fat content. The four calibration models established in the present study should be useful for nutrient quality improvement in rice breeding.     

Hypolipidemic and Body Fat–Lowering Effects of Giant Embryo Brown Rice (Seonong 17 and Keunnunjami) in High‐Fat‐Fed Mice

The effects of giant embryo brown rice Seonong 17 and Keunnunjami, in comparison with that of ordinary normal brown rice, on the body weight and lipid profile in mice under a high‐fat diet condition were investigated. The animals were fed with experimental diets for eight weeks: normal control, high fat (HF), and high fat supplemented with normal brown rice, Seonong 17 rice, or Keunnunjami rice powder. Their body and fat weights, lipid profiles, lipogenic enzyme activities, and adipokine concentrations were determined. Significant differences between the animal groups were analyzed with Tukey's test (P < 0.05). A marked increase in the body weight and fat, plasma triglyceride and total cholesterol concentrations, and free fatty acid level were found in HF mice relative to the control group. On the other hand, diet supplementation with rice, particularly the giant embryo rice samples, significantly suppressed this high‐fat‐induced body weight gain and hyperlipidemia via regulation of lipogenesis and adipokine production. Both the Seonong 17 and Keunnunjami exhibited greater hypolipidemic and body fat–lowering effects than the normal brown rice. The results demonstrate that these giant embryo mutants may be beneficial as biomaterials for functional foods with antiobesity and hypolipidemic effects.     

Effects of Germination Duration on Milling,Physicochemical, and Textural Properties of Medium‐ and Long‐Grain Rice

Germinated brown rice is popular in Asia for its increased γ‐aminobutyric acid (GABA) content and sweeter and softer texture compared with conventional brown rice. However, most studies investigated germinated rice properties on medium‐grain or aromatic rice. The objective of this study was to compare differences between a medium‐grain (Jupiter) and a long‐grain (Wells) rice under similar germination conditions on their milling, physicochemical, and textural properties over the course of germination. Rough rice was soaked in water at 25°C for 12 h and then incubated at 30–34°C for four germination durations. Wells had a higher breakage percentage and a greater weight decrease than Jupiter during germination. Wells had a significantly lower GABA content before germination and at the first two germination durations than Jupiter, but the GABA content in Wells significantly increased at the third germination duration to become significantly higher than that of Jupiter. There were no significant changes in gelatinization temperatures and pasting properties of germinated rice from both cultivars at different germination durations. The cooked rice hardness from Wells decreased at the longest germination duration, whereas Jupiter showed a more significant decrease in cooked rice stickiness from germination. The results demonstrate that the impacts of germination on physical, chemical, and textural properties of rice were affected by grain type and germination duration.     

Rapid Gas Chromatographic Technique for Quantifying 2‐Acetyl‐1‐Pyrroline and Hexanal in Rice (Oryza sativa,L.)

The aroma of rice plays a role in its consumer acceptability. The popcorn‐like smell of aromatic rice stemming primarily from its 2‐ acetyl‐1‐pyrroline (2‐AP) content is considered desirable by many consumers. Conversely, hexanal has been correlated with off odors in rice that develop from lipid oxidation. A rapid method for 2‐AP and hexanal quantification suitable for use in breeding programs, large‐scale research efforts, and quality assurance programs is needed. While developing such a method, sample preparation (degree of milling, particle size), solvent extraction time and temperature, and gas chromatographic parameters were studied. Particle size had no influence on 2‐AP or hexanal recovered. One extraction solubilized ≈80% of the 2‐AP and 56% of the hexanal present in milled rice. The optimum extraction method was assessed to require 0.3 g of ground brown or milled rice in methylene chloride held at 85°C for 2.5 hr. The complete gas chromatographic run requires ≈25 min, and 50 samples can be analyzed per day. The optimized method's linear response (R² = 0.99) and reproducibility was demonstrated. The stability of 2‐AP and hexanal in frozen milled rice and in refrigerated methylene chloride extracts was excellent for at least six months. Milled and unmilled commercial and breeders' aromatic rice samples contained 10–1,104 ng/g of 2‐AP and 148–2,541 ng/g of hexanal. Genotype had the greatest effect on the 2‐AP and hexanal content of two lines grown over four years and in four states.     

Infrared Drying Characteristics of Long‐Grain Hybrid,Long‐Grain Pureline,and Medium‐Grain Rice Cultivars

The objective for this study was to investigate the effectiveness of scaled‐up infrared (IR) heating followed by tempering steps to dry freshly harvested rough rice. An industrial‐type, pilot‐scale, IR heating system designed to dry rough rice was used in this study. The heating zone of the equipment had catalytic IR emitters that provided heat energy to the sample as it was conveyed on a vibrating belt. The sample comprised freshly harvested rough rice of long‐grain pureline (Cheniere), long‐grain hybrid (6XP 756), and medium‐grain (CL 271) cultivars at initial moisture contents of 23, 23.5, and 24% wb, respectively. Samples at a loading rate of 1.61 kg/m² were heated with IR of radiation intensity 5.55 kW/m² for 30, 50, 90, and 180 s followed by tempering at 60°C for 4 h, at a product‐to‐emitter‐gap size of 450 mm, in one‐ and two‐pass drying operations. Control samples were gently natural air dried in an equilibrium moisture content chamber set at relative humidity of 65% and temperature of 26°C to moisture content of 12.5% wb. The effects of IR treatments followed by tempering on percentage points of moisture removed, head rice yield, energy use, rice color, and pasting characteristics were evaluated. For all cultivars, percentage point moisture removed increased with increase in IR drying duration. For all rice cultivars, one‐pass IR treatments for 180 s resulted in head rice yield significantly lower than that of rice dried with natural air in the controlled‐environment conditions (P < 0.05). Energy required to dry rice increased with increase in drying duration. Viscosity values of all the experimental samples were significantly greater (P value < 0.05) than that of the control samples for all the cultivars, except those treated with IR for 180 s. There was a significant difference (P < 0.05) in the color index (ΔE ) of treated milled samples and the controls. In conclusion, the study provided information crucial to understanding the effects of scaled‐up radiant heating and tempering of rough rice on drying rates and rice quality for long‐grain pureline, long‐grain hybrid, and medium‐grain rice cultivars.     

Variation in Polyphenols,Tocols, γ‐Aminobutyric Acid,and Antioxidant Properties in Whole Grain Rice (Oryza sativa L.) as Affected by Different Germination Time

Dynamic alterations in the polyphenols, tocols, antioxidant activities (AOA), and γ‐aminobutyric acid (GABA) contents of white, red, and black germinated rice upon different germination periods were studied. The results indicated that the contents of the free, bound, and total phenolics and AOA steadily increased during germination, even though the free part of colored germinated brown rice (GBR) showed a notable decline at the earlier stages, but still higher than the white rice. The compositions of the nine phenolic acids and six tocols generally accumulated in a time‐ and variety‐dependent manner during the germination process. However, the contents of p‐coumaric, ferulic, and sinapic acids displayed a pronounced increase with the duration of germination in all cultivars. The GABA in white, red, and black GBR accumulated to the highest content at the end of germination, which was 4.7, 14.2, and 6.7‐fold of their respective nongerminated counterparts. Interestingly, the total anthocyanin content in black GBR displayed a constant drop at earlier stages and then a rise at the later stages. These results suggest that prolonged germination may further increase the functional properties of GBR.     

Levels of Avenanthramides and Activity of Hydroxycinnamoyl‐CoA:Hydroxyanthranilate N‐Hydroxycinnamoyl Transferase (HHT) in Steeped or Germinated Oat Samples

Concentrations of avenanthramides and activity of the biosynthetic enzyme hydroxycinnamoyl‐Co A:hydroxyanthranilate N‐hydroxycinnamoyl transferase (HHT) were analyzed in dry or, steeped nonmilled or milled, non‐heat‐treated (raw) or heat‐treated oat samples (Avena sativa L.). Increased avenanthramide concentrations were found when intact raw groats were steeped. The increase was time‐ and temperaturedependent and maximal after 10 hr of steeping at 20°C. Continuous germination in air, after steeping, only contributed to a further increase in avenanthramides when steeping times were shorter than 10 hr. Concentrations of avenanthramides and HHT activity were positively correlated during steeping of intact groats at 8 and 20°C. The increase in avenanthramides was suggested to be due to de novo synthesis and a whole grain structure seemed to be required as no increase was found when groats were milled before steeping. Avenanthramide levels also increased when heat‐treated samples, lacking HHT activity, were steeped. This increase may be due to release of bound forms, possibly formed during the preceding heat treatment.     

Distribution of Protein Bodies and Phytate‐Rich Inclusions in Grain Tissues of Low and High Iron Rice Genotypes

The present study aims to understand whether genotypic differences in grain iron (Fe) concentration in four rice genotypes are related to its association with protein bodies containing phytate‐rich inclusions. Rice genotypes with high and low grain Fe concentrations in unpolished brown rice were grown in a greenhouse at Chiang Mai, Thailand, and grains were harvested at maturity. The presence of protein bodies and phytate‐rich inclusions in rice grain tissues were examined by means of light and transmission electron microscopy (TEM). The composition of mineral elements in different grain tissues was examined using energy dispersive X‐ray microanalysis (EDX) and chemical analysis. The relative distribution pattern of protein bodies in the tissues was similar among the four rice genotypes, which resembled the pattern of grain N concentrations in these tissues. The high grain Fe genotypes (based on brown rice Fe concentration) had more protein bodies containing phytate‐rich inclusions in the embryo and aleurone layer tissues than the low Fe genotypes. Phytate‐rich inclusions were not detected in the endosperm tissues in all genotypes. In conclusion, the presence of protein bodies with phytate‐rich inclusions predominantly in the embryo and aleurone regions of the grain is an important parameter contributing to the variation in brown rice Fe concentration among the genotypes, but not in the white rice (the endosperm). Iron associated with the phytate‐rich inclusions present in the embryo and aleurone layer tissues are largely lost during the polishing process to produce white rice.     

Physical,Chemical, and Sensory Properties of Antioxidant‐Enriched Raw and Cooked Rice by Vacuum‐Drying Impregnation in a Semidry State

Vacuum drying was employed with a vacuum impregnation technique in a semidry state to enrich rice with antioxidants of beetroot juice. The properties of the vacuum‐dried raw and cooked rice grains were characterized. The various raw rice grains (three varieties and two storage time periods) exhibited a significant absorption of beetroot juice, which was evident from the red‐violet beetroot color of the rice, as distinguished from the white color of the control. The color increase (ΔE= 20−40) was linear with the juice content (R² = 0.96−0.99). Their total phenolic (TP) contents and 2,2‐diphenyl‐2‐picrylhydrazyl radical (DPPH) scavenging activities were enhanced (ΔTP = 21−260 mg of gallic acid equivalents/100 g of rice db and ΔDPPH = 22−64 mg of vitamin C equivalents/100 g of rice db). Their grain integrity was reduced (Δforce = −1 to −63), which was potentially associated with the formation of grain surface cracks (linear relationship of %crack and %juice with R² = 0.94−0.98). After cooking, the enriched rice grains were linearly elongated with added juice (R² = 0.88−0.97, up to 1.6‐, 2.0‐, and 2.0‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively), and the overall volume of the cooked rice was increased (likely not linear, up to 3.2‐, 4.3‐, and 4.8‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively). Such improvements in cooking qualities were obtained by this simple vacuum‐drying technique, in comparison to existing rice‐aging processes that are more time consuming. The sensorial scores of the resultant rice products were excellent. Vacuum drying is an effective tool to improve the antioxidant value of rice as well as its cooking quality, and the raw quality remains appreciable. It is a simple and rapid process that could be practical for manufacturing healthy rice products.     

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.     

Tocopherols,Tocotrienols, and γ‐Oryzanol Contents in Japonica and Indica Subspecies of Rice (Oryza sativa L.) Cultivated in Brazil

Whole rice contains several fat‐soluble phytochemicals such as tocopherols, tocotrienols, and γ‐oryzanol which have been reported to possess beneficial health properties. This study was conducted to determine whether brown rice belonging to indica and japonica subspecies were distinguishable from each other regarding the concentration of these compounds by analyzing 32 genotypes. The fat‐soluble compounds were analyzed by normal‐phase HPLC in a single run. The variability of the compounds analyzed was high, but the mean content of γ‐oryzanol across all samples was significantly higher (P < 0.01) in japonica (246.3 mg/kg) than in indica rice (190.1 mg/kg). Similar differences were found for total vitamin E contents which were 24.2 mg/kg in japonica and 17.1 mg/kg in indica rice, respectively. In japonica rice, α‐tocopherol, α‐tocotrienol, and γ‐tocotrienol were the most abundant homologs, while in indica rice the most abundant were γ‐tocotrienol, α‐tocopherol, and α‐tocotrienol. A significant Pearson coefficient (0.80, P < 0.001) between α‐tocopherol and α‐tocotrienol levels was found, independent of the subspecies. Both compounds were positively correlated to total tocols and γ‐oryzanol contents. Although more studies are needed to evaluate the interference of growing rice in different environments and multiple years, the present study provided information on natural variations of the vitamin E isomers and the γ‐oryzanol contents in different rice genotypes.     

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.     

Impact of tillage and crop establishment methods on crop yields,profitability and soil physical properties in rice–wheat system of Indo‐Gangetic Plains of India

Conservation agriculture (CA) based on best‐bet crop management practices may increase crop and water productivity, as well as conserve and sustain soil health and natural resources. In a 2‐year study, we assessed the effects of tillage and crop establishment (TCE) methods on productivity, profitability and soil physical properties in a rice–wheat (RW) system. The six TCE treatments were used to study the impact, which are puddled transplanted rice followed by conventionally tilled wheat (CTPR–CTW), direct‐seeded rice on the flat followed by zero‐till wheat (CTDSR–ZTW), zero‐till direct‐seeded rice with residue followed by zero‐till wheat with residue (ZTDSR+R–ZTW+R), transplanted rice after rotavator puddling followed by zero‐till wheat (RTTPR–ZTW), transplanted rice after rotavator puddling followed by rotary till wheat (RTTPR–RTW) and farmer practice rice–wheat (FP–RW). Result of the study revealed that mean rice yield was not significantly affected by different TCE methods. Wheat planted with ZTDSR+R–ZTW+R gave 30% larger grain yield than FP‐RW. Overall, among all the TCE treatments, the RW system yields and net returns were maximum under ZTDSR+R–ZTW+R. The fastest mean infiltration rate (0.10 cm hr^–1) was registered in ZTDSR+R–ZTW+R plots, whereas the slowest was in FP‐RW plots (0.05 cm hr^–1). Bulk density at 15–20 cm soil depth was least in ZTDSR+R–ZTW+R (1.70 Mg m^–3) and greatest in FP‐RW (1.73 Mg m^–3). Results from this study revealed that conventionally tilled (CT) and transplanting of rice could be successfully replaced by adoption of the profitable double ZT–RW system.