Isolation of cellulose with ionic liquid from steam exploded rice straw

Isolation of cellulose from straw is a bottleneck for exploiting such biomass resources. In recent years, considerable concerns have arisen over new efficient and environmentally friendly way for this purpose. A novel method for cellulose isolation has been proposed by dissolving steam exploded rice straw in 1-allyl-3-methylimidazolium chloride ionic liquid (IL), following regeneration of crude cellulose by diluting the cellulose-ionic liquid solution adequately after separation of insoluble residues. The crude cellulose was then bleached by 2% hydrogen peroxide aqueous solution with low-flux ozone blowing into. No acid-insoluble lignin and only 0.85% hemicelluloses were detected in the bleached cellulose. The isolated cellulose was analyzed by SEM, FT-IR, ¹³C CP/MAS solid state NMR, XRD spectroscopes, and the results indicated that high quality cellulose preparation could be isolated in this manner from rice straw.     

Effect of rice straw management and organic fertilizer application on growth and yield of dry direct-seeded rice

The objectives of this research were to investigate the effect of rice straw management and application of different types of organic fertilizer on growth and yield of dry direct-seeded rice grown under rainfed conditions. The experiment was conducted in a farmer’s field at Muang Yai village, Khon Kaen province in 2005. A split-plot design was used, with the main plot under rice straw management (incorporating into the soil and burning), and sub-plots by type of organic fertilizer (green manure, cattle manure and powder organic fertilizer) and one plot under no-fertilizer application. It was found that rice straw incorporated into the soil had no significant effect on grain yield when compared with the effect of burning. Organic fertilizer of cattle manure and powder organic fertilizer significantly increased grain yield over that of green manure and no-fertilizer application. This paper is listed as a series of articles of the special issue “Water and Food” 6(1), March 2008.     

Effect of pre-extraction on soda-anthraquinone (AQ) pulping of rice straw

The effect of hot-water and alkaline pre-extraction of rice straw on soda-anthraquinone pulping was carried out. The pre-extraction with hot water at 150 °C for 1 h dissolved 34.7% biomass and the pre-extracted liquor comprised of 16.6% sugars, 6.7% lignin, 6.6% acetic acid and other unknown products. But the pre-extraction with 1% NaOH at 100 °C for 1 h dissolved 10.2% sugars, 5.1% lignin and 10% acetic acid from rice straw. Pre-extracted rice straw was cooked by soda-anthraquinone process with varying alkali charges. The pulp from pre-extracted rice straw was low in kappa number with reduced pulp yield. The drainage resistance (°SR) improved obviously on pre-extraction of rice straw. Pulp strength properties such as the tensile index and the burst index were found to be lower, but the tear index was higher both with hot-water and alkaline pre-extraction. After bleaching, the gaps of the overall pulp yield and strength properties between pre-extracted and non-extracted rice straw became narrower. The alkaline pre-extraction showed improved yield and properties compared with hot-water pre-extracted rice straw.     

Effect of lipases on the surface properties of wheat straw

Surface characteristics of untreated and lipase-treated wheat straw (WS) have been investigated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and SEM–Energy dispersive X-ray spectroscopy (SEM–EDX). Static contact angle of WS surface was determined by the pendant drop method. The WS thermal stability was also investigated using the thermogravimetric analysis (TGA). It was shown that the lipases from Candida cylindracea insignificantly changed the chemical group, microscopic morphology, and wettability of the WS inner surface. However, FTIR showed the lipases could effectively remove the hydrophobic lipophilic extractives and silica from the outer surface of untreated WS, and increased the hydroxyl group content in the outer surface. SEM images also exhibited the lipases stripped off the dense hydrophobic layer on the WS outer surface with the help of shear force. SEM–EDX analysis showed that the lipase treatment reduced Si content on the WS outer surface from 12.44 to 1.33%. The water contact angle of the WS outer surface decreased from 92.7° to 65.2° after lipase treatment, which indicated that the wettability of the lipase-treated WS outer surface was equivalent to that of the inner surface with a water contact angle of about 63°. Lipase-treated and untreated WS had a similar thermal stability. Therefore, the lipase treatment was one of the potential methods to improve the wettability of natural fibers in composite material processing. Comparative testing of particleboards produced from the whole WS untreated and treated by the lipases is under way to evaluate the overall effects of the lipase treatment on the improvement in their mechanic performances.     

Mixing groundnut residues and rice straw to improve rice yield and N use efficiency

Groundnut as a pre-rice crop is usually harvested 1–2 months before rice transplanting. During this lag phase much of N in groundnut residues could be lost due to rapid N mineralization. Mixing of abundantly available rice straw with groundnut residues may be a means for reducing N and improve subsequent crop yields. The objectives of this experiment were to investigate the effect of mixing groundnut residues and rice straw in different proportions on (a) growth and yield of succeeding rice, (b) groundnut residue N use efficiency and (c) N lost (¹⁵N balance) from the plant–soil system and fate of residue N in soil fractions. The experiment consisted of six treatments: (i) control (no residues), (ii) NPK (at recommended rate, 38 kg N ha⁻¹), (iii) groundnut residues 5 Mg ha⁻¹ (120 kg N ha⁻¹), (iv) rice straw 5 Mg ha⁻¹ (25 kg N ha⁻¹), (v) 1:0.5 mixed (groundnut residues 5 Mg: rice straw 2.5 Mg ha⁻¹), and (vi) 1:1 mixed (groundnut residues 5 Mg: rice straw 5 Mg ha⁻¹). After rice transplanting, samples of the lowland rice cultivar KDML 105 were periodically collected to determine growth and nutrient uptake. At final harvest, dry weight, nutrient contents and ¹⁵N recovery of labeled groundnut residues were evaluated.     

Effect of supplementation of rice straw with biogas residual slurry manure on the yield, protein and mineral contents of oyster mushroom

Popularity of oyster mushroom is increasing for its ease of cultivation, high yield potential as well as its high nutritional value. Laboratory experimentation followed by farm trial with a typical oyster mushroom Pleurotus sajor caju revealed that the yield potential of these mushrooms can be increased significantly when grown on a lignocellulosic crop residue—rice straw supplemented with biogas residual slurry manure in 1:1 ratio as substrate. Residual slurry manures obtained from biogas plants utilising either cattle dung, poultry litter, jute caddis or municipal solid waste as substrates for biogas production were all effective in increasing the yield of Pleurotus sajor caju significantly although to different extents. Disinfection of straw and manure by means of 0.1% KMnO₄ plus 2% formalin solution in hot water caused 42.6% increase in yield of Pleurotus sajor caju over control, i.e., when disinfection done with hot water. In addition to increased yield, the above treatments caused significant increase in protein content, reduction in carbohydrate and increase in essential mineral nutrients in mushroom sporophores. Thus, it is concluded from the study that supplementation of rice straw with biogas residual slurry manure has strong impact in improving the yield potential, protein and mineral nutrient contents of Pleurotus sajor caju mushroom in Indian subcontinent or similar climatic conditions.     

油菜与小麦秸秆浸出液对水稻种子萌发及幼苗生长的影响

为了解油菜-水稻与小麦-水稻两种轮作体系中水稻生长的差异,分析油菜作为良好茬口的原因,以秸秆在土壤中腐解的溶液为材料,研究多熟种植体系对后作水稻的增产趋势.采用多因素随机区组设计,包括秸秆类型、添加液类型和秸秆浓度三种因素,其中秸秆类型为油菜、小麦秸秆,添加液类型为蒸馏水和营养液,秸秆浓度分别为空白对照(0 g/L)、...     

甘蓝型油菜秸秆水浸液对水稻萌发和生长的化感作用

为探究油-稻种植制度中甘蓝型油菜秸秆对水稻的影响,研究了不同浓度（0、25%、50%和75%）的3种油菜（沣油737、湘杂油553和中双11）秸秆水浸液处理下,五优308和C两优343两个水稻品种种子萌发和幼苗生长的情况。结果表明,与对照相比,秸秆水浸液总体增加了幼苗的苗高和鲜重,低浓度（25%）下会提高水稻种子的发芽率、发芽指数和幼苗的根长,高浓度（50%和75%）下则起抑制作用。随着浓度增加,湘杂油553的秸秆水浸液提高了五优308幼苗的可溶性蛋白含量,同时降低了其总超氧化物歧化酶（T-SOD）和过氧化物酶（POD）活力;但对C两优343幼苗表现相反的化感作用,显著降低了其可溶性蛋白含量,而提高了其T-SOD和POD活力,25%浓度下显著降低了其丙二醛（MDA）含量。75%浓度的中双11水浸液显著提高了五优308幼苗的MDA含量,并降低了POD活力。25%浓度的沣油737显著降低了C两优343的可溶性蛋白含量而提高了T-SOD和POD活力。综合结果表明,油菜秸秆水浸液浓度越高,对水稻的化感作用越强,且不同油菜品种水浸液对不同水稻品种的化感作用存在差异,本研究中沣油737和五优308...     

Dynamical partition of photosynthates in tillers of rice (Oryza sativa L.) during late growth period and its correlation with feeding value of rice straw at harvest

This study was to investigate the dynamical partition of photosynthates in panicle-removed tillers of rice (Oryza sativa L.) during late growth period and its correlation with the feeding value of rice straw at harvest. Four rice cultivars (Liangyou 108, Huaidao 6, Nanjing 43, Nanjing 44) were cultivated in Nanjing under the same management of Jiangsu area, and were sampled from weeks 1 to 5 after anthesis and at harvest in 2008, 2009 and 2010. Then, the content of nonstructural carbohydrates (NSC), hemicellulose, and acid detergent fiber (exclusive of residual ash, ADFom) in tillers were determined. The crude protein (CP) content in tillers at harvest was assayed in 2009 and 2010. Freehand sections of the fourth internode of main culm were made to visualize the starch particles in parenchyma cells in week 1, 3 and 5 after anthesis in 2010. The results showed that the content of NSC decreased sharply from week 1 to 3 and then increased to week 5 after anthesis; hemicellulose in week 5 remained at an approximate level with that of week 1; ADFom increased slightly from week 1 to 3, and then stayed constant till week 5 after anthesis. The starch particles in parenchyma cells of stems decreased from week 1 to 3 and increased slightly till week 5 after anthesis again. The rebounding rate of NSC (NSCRR) was positively correlated with the content of NSC and CP at harvest while negatively correlated with the content of hemicellulose and ADFom at harvest.     

Effect of particle size,shape and surface roughness on bulk and shear properties of rice flour

The present study was conducted to compare the flowability of basmati and non-basmati rice flour with commercially available rice flour. Dynamic and shear properties were characterized on the basis of particle size, shape and surface roughness (measured by Atomic Force Microscope) depending upon the processing conditions. In contrast to commercial rice flour having less particle size (65.3 μm), the particle sizes (171.1–171.9 μm) of both the samples were not significantly different. However, the flowability of the non-basmati rice flour was significantly affected by its particle shape (0.487), surface roughness (124.23 nm) and compressibility (25.32%), making it more cohesive than basmati rice flour but less cohesive than commercial rice flour (1.34 kPa). Also, basic flow energy was significantly higher in both commercial rice flour and non-basmati flour, thus required more energy (197.42 mJ and 147.54 mJ, respectively) to flow than basmati rice flour (130.15 mJ). Overall, flowability was analysed by applying three different pressures (3, 6 and 9 kPa) and among which commercial rice flour was found less flowable (2.26 at 9 kPa) followed by non-basmati rice flour (2.33 at 9 kPa) and basmati (3.35 at 9 kPa) causing bulk handling difficult.     

水稻秸秆对Cu~(2+)静态吸附影响因素的条件优化

采用静态吸附方法研究水稻秸秆对模拟Cu2+废水的吸附效果,分别研究了吸附时间、固液比、p H值、温度和颗粒大小对Cu2+的吸附量和去除率的影响。结果发现,秸秆对Cu2+的吸附主要受吸附时间、固液比、p H值的影响较大。     

Effect of preparation conditions on composition and sensory aroma characteristics of acid hydrolyzed rice bran protein concentrate

Hydrolysates were prepared from rice bran protein concentrate (RBPc) in paste form (P-RBPc), or as spray-dried (S-RBPc) or freeze-dried (F-RBPc) powder by acid hydrolysis with aqueous 0.5N HCl at 95 °C for 12 or 36 h. The forms of the protein raw material had only a slight influence over the sensory aroma characteristics of the liquid hydrolysates. The liquid hydrolysate (S-H-RBPc-12) prepared from S-RBPc with hydrolysis time of only 12 h could produce the desirable aromas as to a similar extent as that of 36 h. In order to demonstrate the effect of drying method on the composition and aroma characteristics, a representative S-H-RBPc-12 was converted into a powder by freeze- and spray-drying techniques. Sensory analysis indicated that the spray-dried powder had higher cracker-like and salty aroma intensities and received a higher overall liking score compared to the freeze-dried hydrolysate powder.     

Effects of glutelin and globulin on the physicochemical properties of rice starch and flour

The effect of two rice endosperm proteins, glutelin and globulin, on the physicochemical properties of rice starch and flour was investigated. Albumin, globulin, prolamin and glutelin were sequentially extracted from defatted rice flour with de-ionised water, 1.5 M NaCl, propan-2-ol and 0.1 M NaOH, respectively, followed by dialysis and lyophilisation. Globulin and glutelin were then added to pure rice starch at various concentrations, separately and together, and the pasting and textural properties of mixtures were analysed by the Rapid Visco Analyser (RVA) and TA-XT2 textural analyser, respectively. The presence of glutelin in rice starch caused an increase in pasting temperature but a decrease in the viscosity parameters of the starch paste. The concentration of glutelin was also positively correlated with the hardness and adhesive properties of the starch gel. The presence of globulin, on the other hand, resulted in a decrease in all the pasting and textural parameters except gel hardness and the changes were linearly correlated with the concentration of the protein for most of the physical parameters. When the two proteins were added to rice starch together, the outcomes in pasting and textural properties were generally dependent upon the relative concentrations of the two proteins, but were also influenced by the presence of the other two protein fractions, albumin and prolamin. The presence of globulin initially accelerated the rate of water absorption by starch during cooking while the presence of glutelin slowed it down, but in both cases, the ultimate amount of water absorbed was significantly lower than that by pure starch. The contrasting effects of the different protein fractions mean that it might be possible to manipulate the textural properties of rice starch and flour to achieve desirable sensory outcomes by varying the proportions of the protein fractions in product formulations.     

Comparative metabolic profiling of pigmented rice (Oryza sativa L.) cultivars reveals primary metabolites are correlated with secondary metabolites

Gas-chromatography coupled with time-of-flight mass spectrometry (GC-TOFMS) was used to analyze the relationships between primary metabolites and phenolic acids in rice (Oryza sativa L.), including six black cultivars and one white cultivar. A total of 52 metabolites were identified, including 45 primary metabolites and seven phenolic acids from rice seeds. The metabolite profiles were subjected to data mining processes, including principal component analysis (PCA), Pearson's correlation analysis, and hierarchical clustering analysis (HCA). PCA could fully distinguish between these cultivars. HCA of these metabolites resulted in clusters derived from common or closely related biochemical pathways. There was a positive relationship between all phenolic and shikimic acids. Projection to latent structure using partial least squares (PLS) was applied to predict the total phenolic content based on primary metabolite profiles from rice grain. The predictive model showed good fit and predictability. The GC-TOFMS-based metabolic profiling approach could be used as an alternative method to predict food quality and identify metabolic links in complex biological systems.     

Effects of prolamin on the textural and pasting properties of rice flour and starch

Prolamin is a major class of rice proteins but its influence on the physicochemical properties of rice is not clear. Rapid Visco Analyser (RVA) and TA-XT2 TPA textural analyses were performed on rice starch with the addition of prolamin extracted from three rice cultivars (Hitomebore, M103 and Amaroo), and on rice flour with the prolamin removed by propan-2-ol extraction. Addition of prolamin to rice starch was found to cause a significant (P<0.05) increase in RVA breakdown viscosity but significant (P<0.05) decreases in hardness, adhesiveness and gumminess of the starch gel. Similarly, when prolamin was removed from rice flour, exactly the opposite effect was observed. Addition of prolamin to rice starch also caused it to absorb water faster during cooking but the gelatinised starch absorbed less water compared with control samples without prolamin.     

Effect of hydrothermal treatment of rice flour on various rice noodles quality

The rice noodle industry in Thailand is facing problems regarding rice flour quality. This research aims to study the effects of hydrothermally modified rice flour on improving rice noodle quality. High-amylose rice flour (Chai Nat 1 variety) was modified using heat–moisture treatment (HMT) and annealing (ANN). Response surface methodology (RSM) with face-centered central composite design (FCCD) was applied to optimize the hydrothermal treatment condition. The effects of treatment conditions – moisture content; heating temperature and heating time on pasting; rheology; and textural properties of rice flour gel – were observed. A contour plot showed that all responses using HMT increased when moisture content and heating temperature increased. But heating time had no significant effect on response variables. ANN showed a lower response than HMT for all parameters. The optimum modified conditions were then matched with those of commercial flour for fresh, semi-dry and dry rice noodles; this showed no significant differences in texture or cooking quality (P≤0.05). The storage modulus (G′) after cooling of HMT (19,100 Pa) was much higher than that of ANN (5490 Pa). The differences in rheological properties of both treatments supported their proper uses to achieve various rice noodle qualities.     

Characterisation and functional properties of Australian rice protein isolates

Albumin, globulin, glutelin and prolamin fractions were isolated from an Australian rice variety (cv. Langi) and characterised by yield, protein content and molecular weight profile using both capillary electrophoresis (SDS-CE) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The influence of pre-extraction enzymatic hydrolysis of starch and heating to 70 °C was also investigated, as was the extraction of the glutelin fraction without prior removal of the albumin and globulin fractions. Pre-extraction treatment affected mainly the albumin fraction, increasing dry matter yield but reducing protein content. SDS-CE was able to separate the protein fractions over a wider molecular weight range than SDS-PAGE, and the peaks from SDS-CE showed slightly higher molecular weight compared to equivalent bands from SDS-PAGE. The glutelin fraction extracted without prior removal of albumin and globulin fractions had different characteristics compared to those obtained by conventional extraction methods. Pre-extraction hydrolysis of starch did not significantly affect the emulsifying, foaming and gelling properties of extracted protein. Although rice glutelin had poor solubility, emulsifying and foaming properties in aqueous systems, it had good gelling properties which could be important for food applications.     

Effect of slope on surface drainage in converted rice paddy

Due to the recent regulation of rice production in Japan, it has become necessary to convert rice paddy to other field crops production. To achieve this, drainage conditions, especially for surface drainage, must be improved. We propose the introduction of a slight slope to improve surface drainage, but the optimal slope must be determined in order to prevent soil erosion caused by excessive slope, as well as increased cost. In Japan, a 0.1% slope has recently come into widespread use and, therefore, the impact on surface drainage must be quantified. In this report, observations were carried out to quantify the impact of a 0.1% slope for converted rice paddy and the following results were obtained: (1) An approximate 0.1% slope enables improvement of 46% of the soil surface saturation area as compared to flat conditions about 10 h after inundation; and (2) Inundated water remains on a flat field, while it moves downward toward the end on a sloped field. These results give a basis for determining a slope on a rice paddy in terms of surface drainage improvement. However, the optimal slope should be decided from various perspectives including engineering, agronomy, and economics etc.     

Effects of semidry flour milling on the quality attributes of rice flour and rice noodles in China

To investigate the effects of semidry-milling on the quality attributes of rice flour and rice noodles, the properties of rice flours and cooking properties of rice noodles prepared with wet-, dry- and semidry-milled rice flours were characterized. The level of starch damage of semidry-milled rice flour at 30% moisture was significantly decreased to the level of wet-milled rice flour (P < 0.05); the whiteness of dry-milled rice flour was decreased compared with wet-milled rice flour (P < 0.05), while that of semidry-milled rice flour was not; the wet- and semidry-milled rice flours showed similar morphology and water hydration properties; the dry milling method reduced significantly the hardness, chewiness, and resilience of rice noodles (P < 0.05) compared with wet-milling, but semidry-milling did not; the cooking qualities of rice noodles produced by semidry-milling were comparable to wet-milling. It indicated the semidry-milling at 30% moisture may provide the protective effects on the characteristics of rice flours, which could be used to produce similar qualities of rice noodles to the wet-milling.