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PubMed1995

The nutritive quality of maize-soybean (70:30) tempe flour.

The nutritive quality of maize-soybean (70:30) tempe flour manufactured by fermentation with Rhizopus oligosporus: Rhizopus orysae (1:1) was determined using weanling rats. Mould fermentation of maize-soybean mixture did not significantly affect its proximate composition. It increased the content of reducing sugars, total acids and aminonitrogen by about 43, 195 and 482 percent, respectively, and decreased phytate content by 46 percent. In vitro iron absorption for maize flour and maize-soybean tempe flour was 2.46 and 5.51 percent, respectively. Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR) for maize-soybean tempe flour and skim-milk diets were 2.71 and 2.96, respectively, for PER, and 3.31 and 3.51, respectively, for NPR. In vivo protein digestibility of the two products was 95.0 and 98.0 percent, respectively.

Animals↗
PubMed1995

Effect of traditional processing of cassava on the cyanide content of gari and cassava flour.

Detoxification of cassava cultivars (30572 TMS and 30555 TMS) during their traditional methods of processing to produce gari and cassava flour has been investigated. The HCN quantitative determination was done using the enzymatic assay. Fermentation of cassava pulp for 96 hours during cassava processing for gari reduced the HCN by 22 ppm (52.4 percent) and 20 ppm (57.3 percent) for 30572 TMS and 30555 TMS respectively. There was no significant difference (P > 0.05) in the HCN content of the two cultivars. Soaking of the sliced cassava tissue for 24 hours in cassava flour production prior to sundrying resulted in 16 ppm (38.1 percent) and 15 ppm (38.4 percent) HCN reduction for 30572 TMS and 30555 TMS respectively. HCN loss during sundrying was 6 ppm (14.3 percent) and 5 ppm (12.8 percent) for the two cultivars. There was significantly (P < 0.05) higher HCN loss in processing of gari than cassava flour. The residual cyanide in gari was 12 ppm for 30572 TMS and 10 ppm for 30555 TMS and that in the flour was 20 ppm for 30572 and 19 ppm for 30555 TMS.

Fermentation↗
PubMed1989

[The transfer of 137Cs and 90Sr into flour, bran and straw from wheat, rye, barley and oats in the years 1982, 1986 (reactor accident in Chernobyl) and 1987 in field studies].

The specific activity of 137Cs and 90Sr from the global fallout, as well as from the fallout after the reactor accident at Chernobyl, was determined in flour, bran and straw from wheat, rye, barley and oats as well in the corresponding soils (Cambisol). The results show that the activity of 137Cs, but not of 90Sr, in the plant material was considerably higher in 1986, and still to some extent in 1987, compared to 1982. For 137Cs an 90Sr, as well as for most cereal samples, the activity in the bran and straw was significantly higher than in the flour. Determination of stable potassium and calcium in all samples revealed that this enrichment is, to a large extent, the result of a comparable enrichment of these elements in brans and straw. The plant/soil concentration ratios, averaged over all cereals, were for 137Cs (1982 and 1987): flour 0.026 +/- 0.018; bran 0.079 +/- 0.042; straw 0.055 +/- 0.027. For 90Sr (1982, 1986, and 1987): flour 0.19 +/- 0.095; bran 0.70 +/- 0.23; straw 2.35 +/- 0.82.

Accidents↗
PubMed1994

Aspergillus flavus and aflatoxin B1 in flour production.

This paper discusses the results of investigations of contamination with aflatoxin-producing fungi and aflatoxin B1 affecting 545 samples of wheat grains, 475 samples of intermediate products of wheat grain being milled to flour (like middlings) and 238 samples of flour. A significant contamination with moulds was detected in analyzed samples. Although Aspergillus (34.87%) and Penicillium (32.37%) dominated, other types were also present, e.g., Cladosporium, Fusarium, Mucor, Alternaria, Rhizopus, Absidia and Trichoderma (listed in order of frequency). The presence of Aspergillus flavus, the known aflatoxin producer, was detected in 9.94% of analyzed samples. Isolates of A. Flavus were capable of producing aflatoxin B1 under favourable conditions. Aflatoxin B1 was found in 76.8% of samples contaminated with A. flavus. The highest contamination with aflatoxin B1 was detected in wheat grain samples (mean value of 16.3 micrograms/kg) and in intermediate products of wheat grain being milled to flour (mean value of 11.13 micrograms/kg). Contamination was lower in flour samples (mean value of 4.13 micrograms/kg). With regard to proposed standards given by the FAO and WHO, under which the content of aflatoxin should not exceed 30 micrograms/kg in food products, only two of 96 samples did not meet these criteria.

Aflatoxin B1↗
PubMed1992

Certain functional properties of defatted pumpkin seed flour.

Defatted pumpkin (C. pepo and C. maxima) seed flour has potential food uses because of its high protein content, 61.4 +/- 2.56%. The functional and electrophoretic properties of the defatted flour were investigated. Polyacrylamide gel electrophoresis and electrofocusing indicated 14 bands of water-soluble protein subunits with isoelectric points between 3.81-8.08 and apparent molecular weights between 19,200 and 97,000 daltons. Minimum nitrogen solubility was observed at pH values between 3.0-7.0 and exceeded 90% at pH above 9.0. Solubility was a function of ionic strength. It appeared that, even at the pH of minimum solubility, the pumpkin seed proteins could be dissolved up to high concentrations by increasing NaCl molarity. The viscosity of flour-water dispersion was affected by flour and salt concentrations, and temperature. The least gelation concentration was 8% (w/v) and the water and oil absorption 24.8 +/- 2.03 and 84.4 +/- 4.05 g/100 g respectively. Sorption isotherms, BET monolayer moisture and binding energy of sorption were also calculated. Both foam capacity and stability were pH dependent.

Adsorption↗
PubMed2004

Determination of benzoyl peroxide and benzoic acid in wheat flour by high-performance liquid chromatography and its identification by high-performance liquid chromatography-mass spectrometry.

An HPLC method on C18 column using a gradient mobile phase is proposed for the separate determination of residual benzoyl peroxide (BP) and benzoic acid (BA) in flour and wheat products. The recoveries obtained were quite excellent, from 96.0 to 99.3% for BP added to the flour, and 91.3% for BA added to the flour. Analysis of 10 samples of commercial foods such as flour and wheat products, detected 0.7 microg/g of BP in imported noodles. Furthermore, we successfully verified the existence of BP by LC-MS. These methods are simple and reliable for determination and verifying the amount of BP and BA in foods since now the use of BP as a food additive is permitted in many countries.

Benzoic Acid↗
PubMedDate not supplied

Ochratoxin a in retail flour.

Flour delivered to a school in the Bournemouth area was found by thinlayered chromatography to contain up to 6.25 mg/dg of ochratoxin. A. Penicillium cyclopium, a fungus known to produce this toxin, was found in discoloured portions of the caked flour. Ochratoxin was also found in a second sack delivered to the school, but not in samples of sound flour or in six samples of flour of varying quality from other sources. The health risk did not appear to be serious.

England↗
PubMed2002

Fusarium toxins in wheat flour collected in an area in southwest Germany.

A total of 60 samples of wheat flour were collected during the first 6 months of 1999 from mills and food stores in an area in southwest Germany. Samples included whole-grain and two types of white flour with these three groups characterized by a high, medium and low ash content. The contents of deoxynivalenol (DON), nivalenol (NIV), 3- and 15-acetyldeoxynivalenol, HT-2 toxin (HT-2), T-2 toxin (T-2) and fusarenon-X (FUS-X) were determined by gas chromatography/mass spectrometry, and those of zearalenone (ZEA), alpha- and beta-zearalenol (alpha- and beta-ZOL) by high performance liquid chromatography with fluorescence detection. FUS-X, alpha- and beta-ZOL were not detected in any sample. Based on incidence and level, DON was the predominant toxin followed by NIV and ZEA for all three flour types. The overall degree of toxin contamination was lower with decreasing ash content. This suggests a localization of the toxins analyzed primarily in the outer parts of the original wheat kernels. The median DON content was significantly (P<0.05) higher for wheat flour originating from wheat of conventional than of organic production.

Chromatography, High Pressure Liquid↗
PubMed2003

Microbiology of wheat and flour milling in Australia.

A survey was undertaken to determine the microbiological status of Australian wheat and the distribution of microorganisms in the flour milling fractions and end products. A total of 650 milling process and end product samples was obtained from nine flour mills located in New South Wales (4), Queensland (2), Victoria (2) and Western Australia (1) during the 1997-1998 and 1998-1999 wheat seasons. Most frequent (modal) counts in wheat and flour were, respectively, as follows: aerobic mesophilic plate count, 10(5) and 10(2) colony forming units/gram (cfu/g); coliforms, 10 and 1 most probable number/gram (MPN/g); Bacillus spp., 10(4) and 10(2) cfu/g; B. cereus, 1 and 0.1 MPN/g; mesophilic aerobic spores, 10 and 1 cfu/g; aerobic thermophiles, both 10 cfu/g; yeasts, 10(3) and 10(2) cfu/g, and moulds, 10(3) and 10(2) cfu/g. Bacillus spp., coliforms, yeasts and moulds were the most frequently detected microorganisms throughout the survey. The most common moulds isolated were Aspergillus, Penicillium, Cladosporium and Eurotium spp. Environmental serovars of Salmonella were isolated from two samples. Escherichia coli and B. cereus were present at very low levels, a majority of positive samples being at the minimum level of detection (3 and 0.3 MPN/g, respectively). As wheat grain layers are separated, surface-adhering contaminants are concentrated in end product bran, wheat germ and pollard, which comprise the outer layers of the grain. Consequently, the inner endosperm fraction contains lower microbial counts, and flour is the cleanest end product of the milling process. Higher microbiological counts midstream in the milling process indicate that equipment contamination may contribute to microbiological contamination; however, the microbiological quality of incoming wheat has a strong influence on the ultimate quality of milling end products.

Australia↗
PubMedDate not supplied

Structure and dynamics of flour by solid state NMR: effects of hydration and wheat aging.

The effects of accelerated aging of wheat seeds on structural and dynamic properties of dry and hydrated (ca 10 wt % H(2)O) flour at a molecular level were investigated by several high and low resolution solid-state NMR techniques. Identification and characterization of domains with different mobility was performed by (13)C direct excitation (DE) and cross-polarization (CP) magic angle spinning (MAS), as well as by (1)H static and MAS experiments. (1)H spin-lattice relaxation times (T(1) and T(1)(rho)) measurements were carried out to investigate molecular motions in different frequency ranges. Experimental data show that the main components of flour (starch and gluten proteins) are in a glassy phase, whereas the mobile fraction is constituted by lipids and, in hydrated samples, absorbed water. A lower proportion of rigid domains, as well as an increased dynamics of all flour components are observed after both seeds aging and flour hydration. Linear average dimensions between 20 and 200 A are estimated for water domains in hydrated samples.

Flame Ionization↗
PubMed2000

Use of fourier transform near-infrared reflectance spectroscopy for rapid quantification of castor bean meal in a selection of flour-based products.

Methodology was developed and evaluated for the rapid detection of castor bean meal (CBM) containing the toxic protein ricin by using Fourier transform near-infrared (FT-NIR) spectroscopy and multivariate techniques. The method is intended to be a prototype to develop a more general approach to detect food tampering. Measurements were made on an FT-NIR system using a diffuse reflection-integrating sphere. Flours spiked with caffeine, crystalline sugar, and corn meal, 1-20% w/w, were used as test articles to evaluate the methodologies. Food matrices (bleached flour, wheat flour, and blueberry pancake mix) spiked with CBM (0.5-8% w/w) were analyzed. Multiplicative scatter correction transformed partial least-squares regression models, using a specific NIR spectral region, predicted CBM contamination in foods with a standard error of cross-validation of <0.6% and a coefficient of determination (R(2)) of >94%. Models discriminated between flour samples contaminated with CBM and other protein sources (egg white, soybean meal, tofu, and infant formula). CBM had loading spectra with bands characteristic of amide groups (4880 and 4555 cm(-1)) and lipids (5800, 5685, 4340, and 4261 cm(-1)).

Caffeine↗
PubMed2002

Important aroma compounds in freshly ground wholemeal and white wheat flour-identification and quantitative changes during sourdough fermentation.

An investigation on the odor-active compounds of wholemeal (WWF) and white wheat flour (WF 550) by aroma extract dilution analysis (AEDA) and by quantitative studies using stable isotope dilution assays (SIDA) revealed a significant number of odor-active compounds, such as (E)-2-nonenal, (E,Z)- and (E,E)-2,4-decadienal, (E)-4,5-epoxy-(E)-2-decenal, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, and vanillin, with high odor activities in both wheat flours. The amounts and, consequently, the aroma potencies of vanillin, (E,E)-2,4-decadienal, and 3-(methylthio)propanal were much higher in the WWF than in the WF 550 samples. Fermentation of suspensions of both flours with lactic acid bacteria did not generate new odorants; however, many compounds, such as acetic acid or 3-methylbutanal, were increased, whereas aldehydes (formed from the degradation of unsaturated fatty acids) were decreased. Comparing the odorant concentrations present before and after fermentation gave evidence that the main influence of the microorganisms on sourdough aroma is to either enhance or decrease specific volatiles already present in the flour. A comparison with literature data indicated that most of these odorants are also important for the bread crumb aroma present after baking of the dough.

Aldehydes↗
PubMed2005

Quantitation of dityrosine in wheat flour and dough by liquid chromatography-tandem mass spectrometry.

A method for the quantitation of dityrosine in wheat flour and dough by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) using an isotope dilution assay with the internal standard 3,3'-(13)C(2)-dityrosine in the single-reaction monitoring mode was developed. The method consisted of the release of protein-bound dityrosine by hydrolysis in 4 mol/L hydrochloric acid/8.9 mol/L propionic acid for 24 h at 110 degrees C after addition of the internal standard, cleanup by C(18) solid-phase extraction, and HPLC-MS/MS. The limit of detection of dityrosine was 80 ng/g of sample (0.22 nmol/g), and the limit of quantitation was 270 ng/g of sample (0.75 nmol/g). The method was sensitive enough to analyze wheat flour and dough and to study the effect of flour improvers on the dityrosine content. Furthermore, the effect of the mixing time was studied. The dityrosine concentration in the flour was 0.66 nmol/g. After we mixed a dough to peak consistency, the dityrosine concentration doubled and remained constant on further mixing. Overdoses of hydrogen peroxide and hexose oxidase (HOX, E.C. 1.1.3.5) resulted in a strongly increased dityrosine content, whereas no increase of the dityrosine concentration was found after the addition of ascorbic acid and potassium bromate. Calculation of the percentage of dimeric tyrosine showed that less than 0.1% of the tyrosine residues of wheat protein were cross-linked. Therefore, dityrosine residues seem to play only a very minor role in the structure of wheat gluten.

Alcohol Oxidoreductases↗
PubMed2005

Spelt (Triticum aestivum ssp. spelta) as a source of breadmaking flours and bran naturally enriched in oleic acid and minerals but not phytic acid.

The nutritional value of breadmaking cereal spelt (Triticum aestivum ssp. spelta) is said to be higher than that of common wheat (Triticum aestivum ssp. vulgare), but this traditional view is not substantiated by scientific evidence. In an attempt to clarify this issue, wholemeal and milling fractions (sieved flour, fine bran, and coarse bran) from nine dehulled spelt and five soft winter wheat samples were compared with regard to their lipid, fatty acid, and mineral contents. In addition, tocopherol (a biochemical marker of germ) was measured in all wholemeals, whereas phytic acid and phosphorus levels were determined in fine bran and coarse bran samples after 1 month of storage. Results showed that, on average, spelt wholemeals and milling fractions were higher in lipids and unsaturated fatty acids as compared to wheat, whereas tocopherol content was lower in spelt, suggesting that the higher lipid content of spelt may not be related to a higher germ proportion. Although milling fractionation produced similar proportions of flour and brans in spelt and wheat, it was found that ash, copper, iron, zinc, magnesium, and phosphorus contents were higher in spelt samples, especially in aleurone-rich fine bran and in coarse bran. Even though phosphorus content was higher in spelt than in wheat brans, phytic acid content showed the opposite trend and was 40% lower in spelt versus wheat fine bran, which may suggest that spelt has either a higher endogenous phytase activity or a lower phytic acid content than wheat. The results of this study give important indications on the real nutritional value of spelt compared to wheat. Moreover, they show that the Ca/Fe ratio, combined with that of oleate/palmitate, provides a highly discriminating tool to authenticate spelt from wheat flours and to face the growing issue of spelt flour adulteration. Finally, they suggest that aleurone differences, the nature of which still needs to be investigated, may account for the differential nutrient composition of spelt and wheat.

Bread↗
PubMed2005

Enzymic degradability of hull-less barley flour alkali-solubilized arabinoxylan fractions by endoxylanases.

The impacts of the arabinose to xylose (A/X) ratio of arabinoxylans (AX) and the endoxylanase substrate specificity on the enzymic degradability of hull-less barley flour AX by endoxylanases were studied by using alkali-solubilized AX (AS-AX) fractions with different A/X ratio, on the one hand, and glycoside hydrolase family 10 and 11 endoxylanases of Aspergillus aculeatus (XAA) and Bacillus subtilis (XBS), respectively, on the other hand. AS-AX were obtained by saturated barium hydroxide treatment of hull-less barley flour water-unextractable AX. Fractionation of AS-AX by stepwise ethanol precipitation resulted in structurally different hull-less barley flour AS-AX fractions. Their A/X ratios increased with increasing ethanol concentration, and this increase in A/X ratio was reflected in their xylose substitution levels. For both XAA and XBS, the enzymic degradability of AX and apparent specific endoxylanase activity decreased with increasing A/X ratio of the AS-AX substrates, implying that both endoxylanases were sterically hindered by arabinose substituents. However, for all AS-AX fractions, hydrolysis end products of lower average degree of polymerization were obtained after incubation with XAA than with XBS, indicating that the former enzyme has a lower substrate specificity toward hull-less barley flour AS-AX than the latter. In addition, apparent specific endoxylanase activities indicated that XBS was approximately 2 times more sensitive to variations in the A/X ratio of AS-AX fractions than XAA. Furthermore, AS-AX with higher A/X ratio were relatively resistant to degradation by XBS.

Aspergillus↗
PubMed2005

In vitro bile acid binding of flours from oat lines varying in percentage and molecular weight distribution of beta-glucan.

Two experimental high beta-glucan oat (Avena sativa) lines (7.64 and 8.05%) and two traditional lines (4.77 and 5.26% beta-glucan) were used to evaluate the effect of beta-glucan quantity and molecular weight on bile acid (BA) binding. The oat flour samples were digested by an in vitro system that simulated human digestion. No significant differences among oat type were found in the overall beta-glucan, starch, and pentosan digestibilities. Considering the standard, cholestyramine, as 100% bound, the relative BA binding for the oat flour samples on a dry matter basis was in the range of 7.5-14.8%, which is higher than the values determined for some other grains and plant materials in the literature. Although the high beta-glucan flours bound a high amount of BA, no significant correlations were found between beta-glucan content in the flours and BA binding. Significant correlations were found between BA binding and insoluble dietary fiber content. Partial hydrolysis with lichenase of the beta-glucan molecules did not affect the BA binding. A summary of all data suggested that BA binding is a multicomponent-dependent process.

Avena↗
PubMed2006

Determination of trace levels of bromate in flour and related foods by ion chromatography.

In this paper, a method of determining trace levels of bromate in flour and related foods by ion chromatography with large volume injection has been proposed. The detection of bromate was performed with a suppressed conductivity detector after separation on an IonPac AS19 column with KOH as the gradient eluent. Parameters affecting the extraction efficiency of bromate, such as the flour-to-water ratio, extraction time, and temperature, were studied in detail. The optimized pretreatment process was then selected. By using the large volume injection technique, the solution detection limit was decreased to 0.5 microg/L. The linear range of this method was from 5 to 1000 microg/L, and the linear correlation coefficient was 0.9998. The method has been applied to the detection of bromate in flour and related foods, and different concentration levels of bromate were detected in various samples. The spiked recoveries ranged from 86 to 110%. The relative standard deviation (RSD) of the bromate peak height for the seven successive injections of the flour sample was 6.4%.

Bromates↗
PubMed2000

Front-surface absorbance spectra of wheat flour: determination of carotenoids.

Front-surface absorbance spectra of wheat flours in the 250-650 nm region can be obtained by measuring reflectance spectra with a conventional spectrofluorometer suitably set to detect light scattered from powder samples. The spectra recorded on flour samples, obtained from seeds of four bread and five durum wheats, show high-intensity absorption bands due to aromatic amino acids of wheat proteins and low-intensity bands due to chromophores bound to low-molecular-weight compounds. The intensity of these last bands is proportional to the concentration of the corresponding chromophores present in the flour; thus, it can be used to measure the content of the compounds containing the chromophore(s). In particular, a quantitative determination of the carotenoids actually present in the flours is made, obtaining information on the original content of the seeds. This determination is important, as, for example, xanthophylls are well-known antioxidants and free-radical scavengers involved in aging processes of seeds. Reflectance measurements on powder samples are far more economic in terms of time and materials consumption than methods such as extraction and HPLC analysis of extracts and, in addition, give an evaluation of the overall content of carotenoids with absorption bands in the spectral range 450-500 nm. Application of the technique to other food powders with low-intensity absorption bands in the near-UV and vis region is possible.

Carotenoids↗