Effects of soaking on physicochemical properties of four kinds of rice used in Huangjiu brewing

Rice soaking is an important step in the Huangjiu brewing process. It affects the subsequent fermentation process and the quality of Huangjiu. However, the mechanism and physicochemical variation of rice soaking have been little studied. The physicochemical characteristics of japonica rice (JR), japonica glutinous rice (JGR), indica rice (IR) and indica glutinous rice (IGR) and their properties during the soaking process were studied and compared. The decreased pasting temperature of soaked rice indicated that they were easier to cook and gelatinize after soaking. The four kinds of rice and the soaked water showed different properties after soaking. During soaking, the total acids and amino nitrogen of the four kinds of rice increased slowly at first, then increased rapidly and finally became stable, while the reducing sugar content increased initially and then decreased. The soaking water of JGR showed the highest values of the physicochemical components, showing that it might be more profitable for further Huangjiu fermentation.     

Evaluation of the Physio-Chemical and Microbial Properties of Green Tea Waste-Rice Bran Compost and the Effect of the Compost on Spinach Production

Abstract

To study the physio-chemical and microbial properties of green tea waste-rice bran compost (GRC), and feasibility of GRC as the alternative of agrochemicals for quality spinach production, five types of compost were prepared by mixing green tea waste and rice bran. The compost temperature was increased by adding rice bran to the green tea waste. The compost GC made from green tea waste alone contained a relatively large amount of nitrogen (7.55%). On the other hand, the compost RC made from rice bran alone contained a relatively large amount of minerals, such as phosphorus (0.49%), potassium (4.96%) and magnesium (2.28%). Addition of rice bran increased the total number of bacteria, viable bacteria and organic matter decomposing bacteria as well as actinomycetes population in the mature compost. The frequency of organic matter decomposing bacteria in GRC was in the following order: cellulolytic bacteria < pectolytic bacteria < lipolytic bacteria < amilolytic bacteria except RC. The growth of spinach was significantly increased over the untreated control (only soil) when GRC was applied in the field and growth pattern was depended on the nature of the composting materials. The highest fresh weight of 27.5 g plant-¹ and 45.4 g plant-¹ were obtained by applying the compost with 30% green tea waste + 70% rice bran (GRC-3) under field condition in autumn of 2004 and 2005, respectively. The highest growth enhance effect was also obtained from GRC-3 when three spinach varieties were grown with GRC under greenhouse condition. The amount of nitrate and oxalate in the spinach grown with GRC were ranged from 114.0 to 146.0 mg 100 g-¹ and 612.0 to 748.0 mg 100 g-¹ fresh weight, respectively. These values were below from the safety standard of health level of nitrate and oxalate for spinach. The amount of ascorbic acid, glutamic acid and iron in the spinach were increased by applying the compost. Among the five combinations of GRC, GRC-3 provided the best results in spinach production.     

Acetylation of intact white rice grains to alter the physicochemical properties

The effect of acetylation of milled rice grains of selected varieties (TDK 8, YRW 4, Reiziq, Amber 33, and SHZ 2) with varying apparent amylose contents (3.8–26.6%) on their physicochemical properties was investigated. Milled rice samples were treated with different acetic anhydride concentrations (0.004–0.04 g per 100 g of milled rice samples in 225 mL of water). Results showed that glutinous (TDK 8), very low amylose (YRW 4) and low amylose containing varieties (Reiziq) were prone to acetylation even with 0.004 g of acetic anhydride. X-ray diffraction patterns showed an increase in the crystallinity in acetylated samples and formation of V-type crystals, suggesting the possible interaction of acetic anhydride with starch. Acetylation of rice grains resulted in reduced peak and final viscosities and gel strength, particularly in glutinous (TDK 8) and very low amylose (YRW 4) rice. Differential calorimetric study showed that acetic anhydride treatment resulted in reduced thermal transition temperatures and enthalpy of all varieties. Although increase in the retrogradation thermal temperatures was observed, the enthalpy of retrogradation was reduced with increasing acetylation, suggesting that the extent of starch retrogradation was lower in all varieties with more prominent reduction in the glutinous type. Furthermore, the texture of cooked acetic anhydride treated rice grains was less hard and showed more adhesiveness. This study demonstrated that the acetylation of rice grains (instead of flour) was successfully achieved, showing the potential of applying acetylation to alter the textural, pasting, thermal and retrogradation properties of rice.     

Close Association between Aleurone Traits and Lipid Contents of Rice Grains Observed in Widely Different GeneticResources of Oryza sativa

Abstract

We investigated 321 varieties to identify the aleurone traits that are closely related to the lipid content of rice. Brown rice seeds were cut crosswise near the center with a razor blade and the cut surface was stained with Oil Red O, and then observed under integrated fluorescence microscope (BZ9000). We found wide variations among varieties in the area stained, but the japonica group contained many varieties with a large stained area. We selected 17 representative varieties covering the whole range of stained areas and confirmed the thickness of aleurone layer using Kawamoto’s film method (micro-thin sections that were created with cryomicrotome). Aleurone traits were examined under a light microscope and measured. We found a strong correlation between the area of the aleurone layer and the stained area (r = 0.799***) and between the thickness of the aleurone layer and the thickness of the stained region (r = 0.543*). The area of the stained region therefore provides a fast and effective indicator for selecting varieties for the thickness of the aleurone layer. We also measured the amount (mg per 100 seeds) and proportion of triacylglycerols (TAGs) to 1 g of seed (mg g-¹) in brown rice seeds without embryos. The amount and proportion of TAG to 1 g of seed were both significantly correlated with the area, average thickness and percentage of aleurone layer. This suggests that the aleurone traits will be good indicators for the selection of varieties with high levels of TAG.     

Screening Cultivars at Low Dissolved Oxygen Level for Water-seeded Rice

Abstract

Eighteen local varieties of japonica rice and two japonica rice varieties introduced from Japan were studied to collect the basic information on the relationship between the amylographic characteristics and eating quality. The materials were planted in the first and second crop seasons of 1998 in central Taiwan. The pasting behaviors including peak viscosity, hot-paste viscosity, cool-paste viscosity, breakdown viscosity, setback viscosity, consistency viscosity, pasting temperature and the time to reach peak viscosity were measured. The eating quality of rice was evaluated by trained panelists in terms of overall palatability score. All amylographic characteristics except for hot-paste viscosity and overall palatability score varied significantly between the first and the second crops and the interactions between crops and varieties were also significant for all characteristics. Teikeng 2, Teikeng 3, Teikeng 4, and Teikeng 9 showed higher overall palatability scores than the other varieties in the first crop, and Koshihikari and Teikeng 6 showed the best overall palatability in the second crop, respectively. The coefficient of variation was higher in the second crop than in the first crop except the time to reach peak viscosity. Setback viscosity showed the highest variation in all amylographic characteristics. The heritability estimate was also higher in the second crop than in the first crop with the exception of consistency viscosity. The highest heritability values were given for consistency and breakdown viscositites in the first and second crops, respectively. However, the lowest heritability value was given for the time to reach peak viscosity in both crop seasons. The close relationship among peak, hot paste, and cool paste viscosities was found for both crops. The highest correlation coefficient was found between peak and breakdown viscosities in both crops. A significant negative correlation between breakdown viscosity and setback viscosity was observed in both crop seasons. Likewise, peak viscosity had a significant correlation with setback viscosity in both crops. In the first crop, the palatability score was negatively correlated with pasting temperature (r=-0.43**) but positively correlated with the time to reach peak viscosity (r=0.36*). There was a positive correlation between palatability score and peak viscosity (r=0.33**) and a negative correlation between palatability score and setback viscosity (r=0.34**) in the second crop.     

Difference in the Physical Properties of White-Core and Non-White-Core Kernels of the Rice Varieties for Sake Brewing is Unrelated to Starch Properties

Abstract

This study was designed to determine whether or not the difference in the physical properties between white-core and non-white-core kernels of the rice varieties for sake brewing is associated with their starch properties. We used two rice cultivars for sake brewing, Senbon-nishiki and Yamada-nishiki, from three different plots in Hiroshima prefecture. Hardness values of kernels were significantly higher in non-white-core than in white-core kernels in both varieties. Vickers hardness (VH) values were lowest at the center of the kernel in both types of kernels. VH values of white-core tissues of white-core kernels were significantly lower than those of corresponding tissues of non-white-core kernels. No significant differences were observed between the two types of kernels in VH values of the surrounding translucent tissues and in the starch properties (amylose content, pasting properties analyzed using a rapid viscoanalyzer and gelatinization properties analyzed using a differential scanning calorimetry). These results suggest that the difference in physical properties between the two types of kernels of the rice varieties for sake brewing are associated with the difference in structure of endosperm cells and not in starch properties.     

Optimization of High-Protein Glutinous Rice Flour Production Using Response Surface Method

A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour (HPGRF). The suspension of glutinous rice flour (15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144–0.222 g/g HPGRF with 29.4%–45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit (KNU)/g α-amylase at 80 °C for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.     

Effects of added water and retrogradation on starch digestibility of cooked rice flours with different amylose content

Flours derived from rice varieties with different amylose content possess distinct physicochemical and molecular properties. The aim of this study was to determine optimal processing conditions for preparing rice flour-based foods with reduced starch digestibility. To do so, we evaluated the in vitro starch digestibility of rice flours with five varieties. Reducing the amount of water (from 10-fold to 4-fold of rice flour) used for cooking rice flour lowered its starch digestibility, and the magnitude of the decrease was positively correlated with amylose content. When retrogradation of cooked rice flour proceeded for 7 days, the digestibility of high-amylose rice flours declined rapidly in the first 3 days, whereas the digestibility of low-amylose rice flours declined continuously. Our analysis also demonstrated that the chain length distribution of starch molecules and the final and setback viscosity pasting properties were the most important parameters affecting the digestibility of rice flours. Based on our results, it appears possible to reduce rice starch digestibility by establishing optimum processing conditions for different varieties. We suggest a 7-fold addition of water and retrogradation for 1 day for high-amylose rice varieties and a 4-fold addition of water with 3 days of retrogradation for low-amylose rice.     

Moisture content is a key factor responsible for inducing rice yellowing

Differences in volatile compounds and the changes in physicochemical properties during the yellowing of glutinous rice were analyzed for investigating its association with water content during storage. The physicochemical analysis indicated that the yellowing led to an enhanced rice viscosity and reduced pasting temperature. More importantly, rice yellowing at higher moisture content resulted in a greater difference in the pasting properties between fresh and the yellowed rice. The changes in the rheological properties of rice appeared to be more sensitive to the initial moisture content, in particular at high moisture condition. In addition, the parameter tanδ might be a key indicator in highlighting the association of rice yellowing with its corresponding dynamic rheological properties. Specially, the volatile compounds detected by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) showed that most of volatile compounds were decreased following the rice yellowing process, which was independent to the initial moisture content of the storage, and the increased level of the storage moisture enhanced the loss of the volatile compounds. Nevertheless, the newly formed volatile compounds during the rice yellowing still noted, and the increase of 1,2,4-trimethyl-bnzene and the decrease of phenol may be the potent to indicating of rice yellowing.     

Effect of Organic Fertilizer and Effective Microorganisms on Growth,Yield and Quality of Paddy-Rice Varieties

Summary

The effect of an organic fertilizer inoculated with Effective Microorganisms (EM) on the growth, yield and quality of 13 paddy-rice varieties varying with maturation period was studied. EM inoculation increased kernel enlargement after the panicle formation stage and also increased ear number and length and kernel number. The yield of brown rice from EM inoculation was higher for the standard fertilizer rate and lower for the higher rate of organic fertilizer. EM inoculation increased the glutinousness and the total quality index of glutinous rice varieties. Under 1993 weather conditions, early and medium-ripening non-glutinous varieties and glutinous varieties were suitable for nature farming with EM-inoculated organic fertilizer.     

Fatty Acid Composition of Three Rice Varieties Following Storage

The petroleum ether extractable lipids (PEE-L) and aqueous propan-1-ol extractable lipids (PWE-L) of three varieties of rice were determined gravimetrically and characterised by fatty acid profiles. The content of PEE-L (22·5–28·2 mg g⁻¹) was higher than that of PWE-L (7·4–11·5 mg g⁻¹) in brown rice with the situation reversed in milled rice (3·0–4·5 mg g⁻¹vs. 7·2–8·7 mg g⁻¹). The ratio of unsaturated fatty acid to saturated fatty acid was about two times higher in PEE-L than that in PWE-L for both brown and milled rice reflecting the selective complexation of saturated fatty acids. Rice storage at 37 °C resulted in some minor but statistically significant changes in the fatty acid profile. In the case of brown rice, the only notable changes were a reduction in the amounts of oleic and linoleic acids in the aqueous propan-1-ol extractable fatty acid fraction (PWE-FA) following storage at the higher temperature. Milled rice of all three varieties showed a decrease in linoleic acid content of PEE-L following storage at 37 °C for 4 and 7 months compared to storage at 4 °C. There was no change in fatty acid contents of PWE-L of milled rice when stored at 4 and 37 °C for 4 and 7 months. This implies that the PWE-L (or bound lipids) were more stable than PEE-L (or free lipids) during storage.     

Relationship between the Amount of Root Exudate and the Infection Rate of Arbuscular Mycorrhizal Fungi in Gramineous and Leguminous Crops

Abstract

We measured the concentration of polyols (pinitol, ononitol, and myo-inositol), which are known to have health-promoting and/or disease-preventing functions, in the common ice plant (Mesembryanthemum crystallinum L.) cultured under salt- and drought-stressed treatments. In NaCl-treated plant the concentration of pinitol/ononitol increased with increasing NaCl concentration in culture solution. The maximal concentration was 3.6 mg g-¹ FW, which was foundin the shoot top, followed by small side shoots (2.1 mg g-¹ FW) of mature plants grown with 400 mM NaCl for 35 ds. The drought stress also accelerated the accumulation of pinitol/ ononitol. The maximal concentration was 1.2 mg g-¹ FW, which was found in the shoot top of plants under the stress for 25 ds. The myo-inositol increased in salt-stressed plants at 3 ds after the start of the treatment and then decreased with the lapse of time during stress. The concentration of polyols in the ice plant was comparable to that in the other species reported to accumulate polyols at high levels. Radical scavenging activity evaluated by DPPH assay was increased two-fold by 400 mM NaCl treatment, which was twice as high as that in the leaves of lettuce (Lactuca sativa L.). These results indicated the high potential of the ice plant as a polyol-rich high-functional food.     

Quality characteristics and field performance of selectable marker-free transgenic rice with antisense Wx gene and improved quality derived from the elite parents of hybrid indica rice

In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types.     

Comparative studies on the storage proteins and anti-nutritional factors from seeds ofPsophocarpus tetragonolobus (L.) DC from five South-East Asian countries

The seeds of 27 varieties ofP. tetragonolobus from six regions of South-East Asia have been examined by polyacrylamide gel electrophoresis. No marked variations in the electrophoretic patterns were found which could be exploited by plant breeders to improve nutritional quality with respect to sulfur containing amino acids. The amino acid compositions of varieties from the different regions showed little variation. Seed extracts of all 27 varieties ofP. tetragonolobus showed trypsin and chymotrypsin inhibitory activities, and hemagglutinating activities. The levels of trypsin inhibitory activities showed some genotypic differences varying from 22.2 to 42.5 mg trypsin inbibited g^?1 of seed meal. As a group the varieties from Malaysia showed the lowest levels of trypsin inhibitor. The chymotrypsin inhibitory activity also showed a similar variation (30.1–47.6 mg chymotrypsin inhibited g^?1 of seed meal). Seed extracts agglutinated type O⁺ and B⁺ human and rabbit erythrocytes with little difference in activity between varieties. Autoclaving winged bean seed meal prior to protein extraction inactivated the anti-nutritional factors and resulted in considerable reduction of protein solubility.     

Quality characteristics and field performance of selectable marker-free transgenic rice with antisense Wx gene and improved quality derived from the elite parents of hybrid indica rice

In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types.     

花生品质的影响因素研究Ⅰ.花生品种因素

研究证明，花生品种类型间和同一类型不同品种间以及同一品种不同成熟度的籽仁，其品质均存在显著差异。粗脂肪含量，最高58．7％，最低43．66％，粗蛋白质含量，最高34．75％，最低21．06％；油亚比（O／L），最高2．173，最低0．807；人体必需氨基酸含量，最高8.93g/100g.最低6.57g/100g；人体必需脂肪酸含量，最高40.68%,最低29．16％，总糖含量，最高6．78％，最低4．56％，VC含量，最高7.38mg/kg，最低2.42mg/kg；VB1含量，最高14.84mg/kg,最低7.96mg/kg;硒含量，最高0.086mg/kg，最低0.072mg/kg。说明影响花生品质首先是品种本身的遗传因子，通过正确运用育种手段可以选育出优质综合和优质专用型花生新品种。     

Effect of germination time on physicochemical properties of brown rice flour and starch from different rice cultivars

The present work was designed to obtain information on the effect of germination time on the selected physicochemical properties of brown rice flour and starch prepared from three different rice cultivars. Changes in total starch, amylose and amylopectin contents of flour, amylopectin/amylose ratio and molecular weight of starch, gelatinization, pasting, rheological, and morphological properties of flour and starch during 5 days of germination were investigated. Significant changes of pasting and rheological properties of brown rice flour were found during germination, but only small changes of these properties could be found in isolated starch. Scanning electron micrographs of flour showed that the continuous matrix structure of flour was highly destroyed after germination and scanning electron micrographs of isolated starch showed that after three days of germination, pits and holes were discovered on the surface of some starch granules. Germination had little effect on the average molecular weight of starch, but the polydispersity value in germinated brown rice (2–5 days germination) was higher than that in non-germinated brown rice. The changes observed in physicochemical properties of brown rice flour and starch after germination provided a crucial basis for understanding flour and starch modification mechanisms with potential applications for an industrial scale.     

Physicochemical and Mochi-making Properties of the Native Red and Black-Kerneled Glutinous Rice Cultivars

Abstract

The physicochemical and mochi-making properties of native red and black-kerneled glutinous rice (RKGR) and white-kerneled glutinous rice (WKGR) of japonica and indica varieties, were examined. In both the japonica and indica varieties, RKGR cultivars contained more protein than WKGR cultivars, the difference being 2.1% and 1.9%, respectively. In both varieties, no significant difference in amylose contents of RKGR and WKGR was observed. The amylographic characteristics of RKGR varied considerably with the variety. In the japonica variety, RKGR cultivars tended to have higher mean maximum viscosity and breakdown values than WKGR cultivars, although the difference was not significant. By contrast, in the indica variety, the mean maximum viscosity and breakdown values of RKGR cultivars were significantly (p<0.05, t-test) lower than those of WKGR cultivars. In both varieties, the difference in gelatinization temperature between RKGR cultivars and WKGR cultivars was not significant. Cooked RKGR cultivars had a higher hardness and a higher hardness/adhesion ratio than WKGR cultivars, although a significant difference between the adhesion of RKGR cultivars. The hardening speed of mochi made from RKGR cultivars tended to be lower than that of mochi made from WKGR cultivars. The hardening speed of mochi showed a significant positive correlation with the atmospheric temperature during the ripening period. The palatability of mochi of RKGR cultivars in both varieties tended to be inferior to that of WKGR cultivars. The particularity of physicochemical and mochi-making properties of RKGR cultivars is considered to be excellent as the processing material and to develop new processed-rice products     

Retrogradation behaviour of milled and brown rice pastes during ageing

Retrogradation of gelatinised starch is the main phenomenon that influences the texture of cooked rice. The rate of retrogradation is affected by several factors including amylose and amylopectin ratio, protein and fibre. The objective of this study was to analyse the pasting properties and the retrogradation behaviour of six traditional and five aromatic Italian rice varieties. The pasted gels, after cooling, were evaluated by dynamic rheological measurements for up to 7 days of storage at 4 °C. The samples were also analysed by a NIR spectrometer. The pasting properties and the retrogradation behaviour of milled rice flours strongly depended on the rice varieties. During gel ageing, a noticeable increase of G′ and G″ was observed only for the milled rice varieties Asia, Gange, Fragrance and Vialone Nano, characterised by a high amylose content. No further hardening was found either for the other milled varieties or for all the brown samples. The methods used in this work (dynamic oscillatory rheometry and FT-NIR spectroscopy) turned out to be very useful in the definition of rice starch gels ageing.     

Influence of rice varieties,nitrogen management and planting methods on methane emission and water productivity

A field experiment was conducted during rainy seasons of 2009 and 2010 at New Delhi, India to study the influence of varieties and integrated nitrogen management (INM) on methane (CH₄) emission and water productivity under flooded transplanted (FT) and aerobic rice (AR) cultivation. The treatments included two rice (‘PB 1’ and ‘PB 1121’) varieties and eight INM practices including N control, recommended dose of N through urea, different combinations of urea with farmyard manure (FYM), green manure (GM), biofertilizer (BF) and vermicompost (VC). The results showed 91.6–92.5 % lower cumulative CH₄ emission in AR compared to FT rice. In aerobic conditions, highest cumulative CH₄ emission (6.9–7.0 kg ha^?1) was recorded with the application of 100 % N by organic sources (FYM+GM+BF+VC). Global warming potential (GWP) was significantly lower in aerobic rice (105.0–107.5 kg CO₂ ha^?1) compared to FT rice (1242.5–1447.5 kg CO₂ ha^?1). Significantly higher amount of water was used in FT rice than aerobic rice by both the rice varieties, and a water saving between 59.5 and 63 % were recorded. Under aerobic conditions, both rice varieties had a water productivity of 8.50–14.69 kg ha^?1, whereas in FT rice, it was 3.81–6.00 kg ha^?1. In FT rice, a quantity of 1529.2–1725.2 mm water and in aerobic rice 929.2–1225.2 mm water was used to produce one kg rice. Thus, there was a saving of 28.4–39.6 % total water in both the rice varieties under AR cultivation.