Action of rice bran phytase on hydrolysis of phytin

The hydrolytic activity of rice bran phytase in relation to phytin and other inositol phosphates has been studied. The maximum activity is exhibited at pH 5.2 and 50°C. Being present in a state of binding with hydrated phytin complexes, phytase hydrolyses endogenous phytin intensively. The affinity of the enzyme present in the form of the complex with exogenous sodium phytate is extremely low. The results of the investigation have provided the possibility of revealing the reasons for the quantitative change in the amount of phytin in rice bran as a function of the technological parameters of the heat treatment of the raw material and the extraction of inositol phosphates.All-Union Scientific-Research and Chemical Engineering Institute, Medical and Microbiological Industry of the USSR, Tashkent. V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 703–707, September–October, 1989.     

Method for obtaining phytin from rice middlings

It has been established that the product of the transformation of phytin (phosphate) is absent from unroasted rice middlings. It is not formed, either, when phytin is heated at 160–200°C for 3 h. It is assumed that the phosphate is possibly formed under the conditions of high temperature and pressure (in the roasting of rice middlings) by the interaction of phytin with other substances present in the rice middlings. It has been found that the use of formalin in the production of phytin is undesirable.     

Method for obtaining phytin from rice middlings

It has been established that the product of the transformation of phytin (phosphate) is absent from unroasted rice middlings. It is not formed, either, when phytin is heated at 160–200°C for 3 h. It is assumed that the phosphate is possibly formed under the conditions of high temperature and pressure (in the roasting of rice middlings) by the interaction of phytin with other substances present in the rice middlings. It has been found that the use of formalin in the production of phytin is undesirable.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 540–543, July–August, 1979.     

Lipids of rice bran

The class and fatty-acid compositions of the total lipids and phospholipids and the types of triacylglycerols of rice bran oil have been studied. It has been shown that the main lipid class consists of the triacylglycerols; in them the 160, 181, and 182 acids predominate. The main phospholipids are the PCs, PIs, and PEs. The predominating TAGs are the trisaturated and the monosaturated-diunsaturated types, which are present in equal amounts.This work was conducted with the financial support of GKNT RUz [State Committee of the Council of Ministers for Science and Technology, Republic of Uzbekistan] and Uzfarmprom.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 302–305, May–June, 1998.     

Kinetics of the hydrolysis of biopolymers in the production of phytin

All-Union Scientific-Research Institute of the Chemical Technology of the Medical and Microbiological Industry, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 419–420, May–June, 1990.     

微生物发酵米糠制备神经酰胺

用CO2激光辐射筛选培育出高产鞘磷脂酶的工程菌——雅致放射毛霉变异株AE255-6。AE255-6固体发酵产鞘磷脂酶的优化条件经试验确定为采用变温培养,培养时间共72h,前24h培养温度30℃,后48h培养温度25℃,培养基pH 7.0—8.0,培养基含水量65%,接种量12%。以米糠为原料,采用AE255-6固体发酵产生鞘磷脂酶以定向水解鞘磷脂产生游离神经酰胺,使米糠中游离神经酰胺含量从0.022%提高到0.064%。将CO2超临界萃取技术与D140大孔树脂纯化相结合,获得纯度为99.2%的神经酰胺产品。产品纯度与美国S igm a公司的相当,且经检测证明其安全性好。     

Enzymatic hydrolysis of ammonia-treated rice straw

Rice straw pretreated with liquid anhydrous ammonia was hydrolyzed with cellulase, cellobiase, and hemicellulase. Ammonia-processing conditions were 1.5 g of NH₃/g of dry matter, 85°C, and several sample moisture contents. There were four ammonia addition time (min)-processing time (min) combinations. Sugars produced were analyzed as reducing sugars (dinitrosalicylic acid method) and by high-performance liquid chromatography. Monomeric sugars increased from 11% in the nontreated rice straw to 61% of theoretical in treated rice straw (79.2% conversion as reducing sugars). Production of monosaccharides was greater at higher moisture content and was processing time dependent. Glucose was the monosaccharide produced in greater amounts, 56.0%, followed by xylose, arabinose, and fructose, with 35.8, 6.6, and 1.4%, respectively.     

Isolation of phytin from cottonseed meal

Summary A method has been developed for isolating phytin from the waste material (mother solution after the precipitation of protein) obtained in the production of fodder protein from cottonseed meal.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 530–532, July–August, 1976.     

Preparation of phytin from cottonseed meal

Summary The optimum conditions for the drying of phytin from cottonseed meal have been determined.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 767–769, November-December, 1978. Original article submitted June 30, 1978.     

Removal of Cr(VI) from wastewater using rice bran

The novel biosorbent rice bran has been successfully utilized for the removal of Cr(VI) from wastewater. The maximum removal of Cr(VI) was found to be 99.4% at pH 2.0, initial Cr(VI) concentration of 200 mg l(-1), and temperature 20 degrees C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium, and temperature was investigated. The adsorption kinetics was tested for first-order reversible, pseudo-first-order, and pseudo-second-order; reaction and the rate constants of kinetic models were calculated. Mass transfer of Cr(VI) from the bulk to the solid phase (rice bran) was studied at different temperatures. Different thermodynamic parameters, viz., changes in standard free energy, enthalpy, and entropy, have also been evaluated and it has been found that the reaction was spontaneous and endothermic in nature. The Langmuir and Freundlich equations for describing adsorption equilibrium were applied to data. The constants and correlation coefficients of these isotherm models were calculated and compared. Desorption studies was also carried out and found that complete desorption of Cr(VI) took place at pH of 9.5. The data were also subjected to multiple regression analysis and a model was developed to predict the removal of Cr(VI) from wastewater.     

Biological heat generation by the cultivation ofAlternaria alternata in rice bran

Biological heat generation was observed whenAlternaria alternata was grown in rice bran. A temperature of more than 50°C was maintained for 25 d, and the maximum temperature was 56.5°C. After 30 d of cultivation, 55% of the energy of rice bran was liberated. The consumption rates of the lipids and sugar contained in rice bran increased with the increase of the maximum temperature during the cultivation ofA. alternata.     

Partial degradation and biological activities of an antitumor polysaccharide from rice bran.

A rice bran polysaccharide designated RON was subjected either to partial hydrolysis with formic acid or to partial degradation by ultrasonic irradiation. A significant change in the molecular size was also observed during simple chromatography of RON on a strongly acidic ion exchange resin, although the apparent molecular weight of RON had been assumed to be more than 1 x 10(6) daltons (Da). This fact indicates that RON exists as molecular aggregates, presumably mediated by metal cations. Degradation products with average molecular weights above ca. 1 x 10(4) Da which were obtained by any of the three methods still retained the following activities of RON: in vivo antitumor activity against Meth-A fibrosarcoma in mice by oral administration, and in vitro macrophage stimulatory effects to induce tumoricidal activity and interleukin 1 production. This molecular size was proven to be the minimum requisite for these activities because smaller fragments were scarcely active. The aggregation was characteristic of RON but not essential for its antitumor activity because definite, though slightly reduced, activity was exhibited even by the smaller fragments obtained after the ion exchange resin treatment.     

Effect of cross-linking and enzymatic hydrolysis composite modification on the properties of rice starches

Native rice starch lacks the versatility necessary to function adequately under rigorous industrial processing, so modified starches are needed to meet the functional properties required in food products. This work investigated the impact of enzymatic hydrolysis and cross-linking composite modification on the properties of rice starches. Rice starch was cross-linked with epichlorohydrin (EPI) with different concentrations (0.5%, 0.7%, 0.9% w/w, on a dry starch basis), affording cross-linked rice starches with the three different levels of cross-linking that were named R?, R?, and R?, respectively. The cross-linked rice starches were hydrolyzed by α-amylase and native, hydrolyzed, and hydrolyzed cross-linked rice starches were comparatively studied. It was found that hydrolyzed cross-linked rice starches showed a lower the degree of amylase hydrolysis compared with hydrolyzed rice starch. The higher the degree of cross-linking, the higher the capacity to resist enzyme hydrolysis. Hydrolyzed cross-linked rice starches further increased the adsorptive capacities of starches for liquids and decreased the trend of retrogradation, and it also strengthened the capacity to resist shear compared to native and hydrolyzed rice starches.     

Comparison of three spectrophotometric methods for the determination of gamma-oryzanol in rice bran oil

A comparison of the results obtained by applying three spectrophotometric methods (at fixed wavelength, second-derivative and multicomponent analysis) to the determination of gamma-oryzanol in rice bran oil is reported.At fixed wavelength the results are more accurate when using isopropyl alcohol, rather than n-heptane, to dilute the oil samples, because the absorption bands of gamma-oryzanol are red-shifted and the absorbance, measured at lambda(max)=327 nm, is less affected by the interference of the oil "matrix" (lambda(max)=314 nm in n-heptane).However, to obtain accurate results also in oils with a low content of gamma-oryzanol, it is necessary to perform the analysis using second-derivative ((2)D330.365) or multicomponent (lambda=310-360 nm) methods. The first one fully removes the interference of oil matrix whilst the second, which needs a specific computational program to process the spectrophotometric data, furnishes evidence the presence of some unexpected interference in the analysis and/or standards which are not representative of the analysed samples, from the square root of the sum of the squared differences at each point between the linear combination of the standards and the unknown spectra (RMS error).Finally, some aspects of the chemical, spectroscopic (UV, IR) and thermoanalytical (TG, DSC) behaviour of gamma-oryzanol and the values of the parameters which enable "computation" of its UV spectra are reported.     

A new method for simultaneous estimation of unsaponifiable constituents of rice bran oil using HPTLC

Rice bran oil (RBO) is rich in a variety of bioactive phytochemicals otherwise known as unsaponifiable constituents (USC). Oryzanols, phytosterols, tocols, etc. are the major USC in RBO; the methods presently used for their estimation involve different techniques and require pretreatment of the sample. In this paper standardization of a simple method for simultaneous estimation of USC directly from RBO using HPTLC is presented. The method involves a two-stage separation of USC on a precoated silica gel 60 F(254 )TLC plate viz.: TLC-1 to separate sterols, oryzanols and tocols; TLC-2 to separate steryl esters, wax, and squalene. Calibration plots using the respective standards were made to determine LOD, LOQ, and linear regression equations. Recovery studies were also conducted and the values ranged from 93.45 to 101.97%. The LOD and LOQ values showed the sensitivity of the method. The instrumental precision was found to be in the range of 0.30 to 1.18 CV%. Quantitative estimation of USC in crude RBO and refined RBO using this method gave a concentration of 52.80 mg/g of USC in the crude and 33.48 mg/g in the refined oil. The present method for estimation of USC using HPTLC is fast, simple, accurate, precise, and sensitive, as demonstrated here.     

Supervised pattern recognition to discriminate the geographical origin of rice bran oils: a first study

Supervised pattern recognition appears to be a useful tool to authenticate foodstuffs according to their geographical or varietal origin, when a set of samples whose classification is known a priori are available. In this work, linear discriminant analysis and artificial neural networks trained by the back-propagation algorithm have been used to discriminate rice bran oils manufactured in three different countries (Italy, Thailand and Switzerland) according to their geographical origin. The variables to be included in the mathematical models have been chosen by means of Fisher F-ratio value among the chemical indices routinely determined on vegetable oils (particularly fatty acids, triglycerides and sterol composition). The prediction ability of all the classifiers was 100% as evaluated by cross-validation.