Changes of vitamin E content in rice bran with different heat treatment

Oil yield from unheated rice bran was 17.6% whereas that of microwave‐heated rice bran increased to up to 18.4%. Content and composition of vitamin E in rice bran oil were affected by microwave heating. Especially, contents of α‐tocopherol, α‐tocotrienol, and γ‐tocotrienol as well as total vitamin E were significantly (P <0.05) increased when the rice bran was subjected to microwave heating for up to 30 s. When rice bran was heated in an electric roaster up to 20 min at 170 °C, 5 min at 180 °C, and 3 min at 190 °C, the total vitamin E content in rice bran oil increased significantly (P <0.05) followed by a considerable decline beyond those time points. Microwave heating was more effective for an increase in the vitamin E content than electric roaster heating. However, longer heating with both microwave and electric roaster caused a significant degradation of vitamin E resulting in a decreased content of total vitamin E.     

Tocol levels in milling fractions of some cereal grains and soybean

Tocol levels in the milling fractions of rice, barley, corn, wheat, and soybeans were analyzed by HPLC with a fluorescence detector. Among all milling fractions tested in this study, rice germ had the highest total tocol levels. In the four milling fractions of barley, except pearling flour, all eight tocol isomers were detected, and they were more uniformly distributed than in any other cereal grains measured in this study. The total tocol and α-tocopherol levels of wheat germ were significantly (P<0.05) higher than the other wheat milling fractions. A significantly (P<0.05) higher proportion of γ-tocopherol was obtained from corn germ (71.5%) and endosperm (50.3%) than from corn hulls. Only four tocol isomers (α-, β-, γ-, and δ-tocopherol) were detected in soybean milling fractions; no tocotrienol isomers were detected. The δ-tocopherol level of soybean endosperm, although minor, was significantly higher than those in milling fractions of other cereal grains in this study.     

Identification and quantitation of γ-oryzanol components and simultaneous assessment of tocols in rice bran oil

A reverse-phase high-performance liquid chromatography method was developed for the simultaneous separation and quantitation of tocopherols, tocotrienols and oryzanols present in rice bran oil. Tocopherols and tocotrienols were quantitated by fluorescence detection and oryzanols (ferulic acid esters of sterols and triterpene alcohols) by photodiode array detection. Chemical ionization mass spectrometry was used to identify cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campesteryl ferulate, β-sitosteryl ferulate and cycloartanyl ferulate as the major oryzanols separated by this procedure. The levels of these nutritionally significant components were found to vary in fully processed, edible rice bran oils from different manufacturers.     

Effect of roasting temperature and time on the chemical composition of rice germ oil

Compositional changes of rice germ oils prepared at different roasting temperatures (160–180°C) and times (5–15 min) from rice germ were evaluated and compared with those of unroasted rice germ oil. The color development and phosphorus content of oils increased significantly as roasting temperature and time increased, whereas the FA compositions of rice germ oils did not change with roasting temperature and time. Four phospholipid classes, i.e., PE, PI, PA and PC, were identified. PE had the lowest stability under roasting conditions. There were no significant differences in γ-oryzanol levels of rice germ oils prepared at different roasting temperatures and times. Four tocopherol isomers (α−, β−, γ−, and δ-tocopherol) and three tocotrienol isomers (α−, γ−, and δ-tocotrienol) were identified, but no β-tocotrienol was detectable. The content of α− and γ−tocopherol in rice germ oil gradually increased as roasting temperature and time increased.     

Relative FFA formation and lipid oxidation of commercially milled unseparated,head, and broken rice

This study was conducted to determine the relative rate of FFA formation and lipid oxidation of unseparated (head and broken), head, and broken rice and the effect of water washing on the lipid quality of broken rice. A regression model was developed with surface FFA or conjugated diene (CD) content vs. incubation time to determine the rates of FFA formation and lipid oxidation. The surface lipid contents of unseparated, head, and broken rice were 0.40, 0.38, and 0.50% of rice, respectively. FFA formation during storage showed three phases: an initial rapid formation, followed by a period of very little or no formation, and finally a phase of gradual formation. In contrast, CD formation initially showed a slow increase but later increased gradually with storage time. The relative rates of FFA and CD formation of unseparated, head, and broken rice were 0.0028, 0.0027, and 0.0036 and 0.192, 0.188, and 0.377, respectively. Water washing reduced the rates of FFA formation and lipid oxidation of broken rice to 0.0015 and 0.2192 from initial values of 0.0031 and 0.369, respectively. Water washing appears to be a simple and practical means of lowering the rates of FFA formation and lipid oxidation in broken rice.     

新型海藻水稻专用叶面肥对不同品种水稻的增产效应

采用大田试验,研究了喷施新型海藻水稻专用叶面肥在不同品种水稻上的增产效果。结果表明,施用海藻水稻专用叶面肥对5个品种水稻(郑稻18、南粳49、南粳44、甬优2640和Y两优1号)均有增产作用。从产量构成因子分析,促进增产的主要原因是提高了水稻有效穗数和穗粒数。然而,不同品种水稻增产幅度不同,Y两优1号和郑稻18的增幅最大,其次是甬优2640。从经济效益分析,郑稻18和甬优2640的增加产值和产投比高于其他3个品种。综合而言,海藻水稻专用肥在郑稻18、甬优2640和Y两优1号上的施用效果相对较好。     

Oxidative stability of high-fatty acid rice bran oil at different stages of refining

The contents of natural antioxidants and the oxidative stability of rice bran oils at different refining steps were determined. Tocopherols and oryzanols were constant in crude and degummed oils but decreased in alkali-refined, bleached and deodorized oils. The process of degumming, alkali-refining, bleaching and deodorization removed 34% of the tocopherols and 51% of the oryzanols. During storage of deodorized oil for 7 wk, 34% of the tocopherols and 19% of the oryzanols were lost. The maximum weight gain, peroxide value and anisidine value were obtained from alkali-refined oil during storage. The order of oxidation stability was crude ≥ degummed > bleached = deodorized > alkali-refined oil.     

Determination of nonvolatile components in polar fractions of rice bran oils

High-oryzanol rice brain oil (HORBO), rice bran oil (RBO), and partially hydrogenated soybean oil (PHSBO) were used to prepare french fries. Polar fractions of the three oils were analyzed for nonvolatile components by high-performance size-exclusion chromatography (HPSEC) with ELSD. In all frying experiments, both HORBO and RBO yielded predominantly dimeric and monomeric materials. The concentrations of polymeric species in HORBO and RBO were greater than in PHSBO. The major degradation products from HORBO, RBO, and PHSBO were dimers (8.93 mg/100 mg oil), monomers (10.5 mg/100 mg oil), and DG (22.4 mg/100 mg oil), respectively. Thermal degradation via hydrolysis was much greater in PHSBO than in HORBO or RBO. Distribution data indicated that the extent of polymer formation from frying was in the order RBO>HORBO >PHSBO, consistent with the degree of lipid unsaturation and the oryzanol content in these oils. HPSEC-ELSD results from the two RBO showed that the amounts of various polymeric species, including trimers and higher polymers, were lower in HORBO than in RBO. The percentage of polar materials and the percentage of polymerized TG, which were used as indicators of oil quality and stability, decreased with increasing tocopherol and oryzanol contents in the order PHSBO>HORBO>RBO.     

水稻专用肥不同配方在早稻上的试验效果

水稻专用肥配方试验研究结果表明:当m(N)∶m(P2O5)∶m(K2O)在1∶(0.3～0.5)∶(0.8～1.2)范围内,稻谷产量没有明显差异,说明现用水稻专用肥1∶0.3∶1.2的配方合理;但由于目前钾肥价格过高,影响水稻种植的经济效益,故水稻专用肥配方宜调整到1∶0.4∶0.8,控制低钾水平。     

Antioxidant effects of d-tocopherols at different concentrations in oils during microwave heating

The effects of d-tocopherols at different concentrations (50 to 1000 ppm) on the oxidative stability of ethyl linoleate and tocopherol-stripped oils were investigated under microwave heating conditions. Purified substrate oils were prepared by aluminum oxide column chromatography. After the addition of tocopherols (α-, β-, γ- or δ-) to the oils, peroxide, carbonyl andp-anisidine values were measured in the samples after heating in a microwave oven. Further, the residual amount of tocopherol homologues in the oils after heating was determined by high-performance liquid chromatography for evaluation of their effects at different concentrations on oxidative deterioration. Microwave heating resulted in some acceleration in the oxidation of the purified substrate oils. Optimum concentrations of tocopherols required to increase oxidative stability were 100 ppm for α-, 150–200 ppm for β- or γ- and 500 ppm for δ-tocopherol, respectively. The antioxidant effect of tocopherols decreased in the order α>β ≒ γ>δ at each level, in all substrates. Therefore, α-tocopherol was consumed first, followed by β- or γ-tocopherol, and δ-tocopherol was consumed more slowly. The tocopherols had no further significant antioxidant activity (P>0.05) at concentrations higher than 500 ppm.     

Flour rice husk as filler in block copolymer polypropylene: Effect of different coupling agents

Flour rice husk (FRH) was employed as a filler in block copolymer polypropylene (PPB) in order to prepare polymer‐based reinforced composites. Four coupling agents were selected to modify the surface of the rice husk in the composite materials, including two types of functionalized polymers [PP homopolymer grafted with maleic anhydride (MA‐PP) and an elastomer styrene–ethylene–butadiene–styrene triblock copolymer grafted with MA (MA‐SEBS)] and two bifunctional organometallic coupling agents (silane and titanate with linear low‐density polyethylene as a carrier). The influence of each type of coupling agent on the interfacial bonding strength was studied by dynamic mechanical analysis, scanning electronic microscopy, and rheological tests. The results showed that strong interactions were formed between the coupling agents and the filler surface. The addition of a coupling agent with an elastomeric carrier (MA‐SEBS) increased the loss tangent and reduced the storage modulus of the composite. A similar but less intense effect was observed for the titanate coupling agent. However, an antagonistic performance was obtained when MA‐PP and silane were employed as coupling agents. In addition, when the percentage of MA‐SEBS was increased, the impact properties of FRH/PPB blends were improved and the strength was reduced. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1823–1831, 2006     

生活垃圾主要组分在回转窑内不同热解阶段的传热特性

采用外热式回转窑,对生活垃圾主要组分[纸类、织物、生物质类(含厨余)]及除去惰性成分的垃圾在不同的升温速率和不同转速下热解过程中的传热特性进行研究,获得物料和内壁面之间的表观传热系数.根据相近升温速率下热重分析结果将热解过程分为干燥阶段、热解预备阶段、剧烈热解阶段以及热解完成阶段4个阶段.研究结果表明:在干燥阶段的表观传热系数最大,并随着温度升高而迅速减小,到水分蒸发完、进入热解预备阶段时降至最低.在热解预备阶段的升温过程中,各物料表观传热系数随温度升高基本不变,具备最低稳定传热系数特征;在剧烈热解阶段,表观传热系数随温度升高而逐渐增大;在热解完成阶段,表观传热系数再次减小.回转窑转速和升温速率对表观传热系数的影响复杂,对不同物料的影响也不相同.总体上在较低的加热速率(22±2)℃·min^-1条件下,更高的回转窑转速(3 r·min^-1)对干燥末段和热解预备阶段的传热有抑制效果;当升温速率增加到(32±2)℃·min^-1时,各种物料在对应热解段的表观传热系数均有增大的趋势,且热解总时间缩短;除生物质外,转速越高,在热解的不同阶段表观传热系数越大,在3 r·min^-1条件下热解预备阶段消失.本研究为回转窑热解反应器的针对性设计提供参考.     

Role of plant volatiles in resistance of selected rice varieties to brown planthopper,Nilaparvata lugens (Stål) (Homoptera: Delphacidae)

Rice plant volatiles extracted as steam distillates significantly affected the behavior and biology of the brown planthopper,Nilaparvata lugens (Stål). In a multichoice test, more females settled and fed on tillers of a susceptible rice variety Taichung Native 1 (TN1), sprayed with its own extract or acetone than on TN1 tillers sprayed with the extract of the resistant variety ARC6650 or Ptb33. In another test,N. lugens females ingested significantly more of a 10% sucrose solution mixed with TN1 steam distillate extract than of plain sucrose solution or that mixed with extracts of resistant varieties. Topical application of the extracts of resistant varieties Mudgo, ASD7, Rathu Heenati, Babawee, Ptb33, and ARC6650 caused significantly higher mortality of females than did the TN1 extract. Likewise, significantly more first-instar nymphs died when they were caged on susceptible TN1 plants sprayed with the extracts of resistant varieties than on plants sprayed with TN1 extract. The extract of 60-day-old resistant plants was more toxic than the extract of 30-, 45-, or 100-day-old plants. However, toxicity of the extract from susceptible TN1 remained low at all plant growth stages.Principal Research Scientist (ICIPE), based at International Rice Research Institute (IRRI), P.O. Box 933, Manila, Philippines.     

Composition of an SRC-II coal-derived liquid: Changes in composition resulting from hydrotreatment at different levels of severity

An SRC-II coal-derived liquid fuel and eight upgraded coal liquids derived from it were separated into chemical class-type fractions by preparative liquid chromatography. Mass and infrared spectroscopy, gas chromatography and non-aqueous titration were used, together with the mass balance data from the l.c. separations, to describe changes in composition of the liquids as a function of severity of hydrotreating conditions. The relative abundance of the following classes of compounds was determined in each of the liquids : saturates, monoaromatics, diaromatics, polyaromatics, total acids, total bases, hydroxyarenes, strong acids, pyrrolic benzologs, carbonyl compounds (amides), basic diarylamines, basic monoarylamines, azaarenes, and strong bases. The results are discussed in the light of known reaction pathways for aromatic ring saturation and heteroatom removal.