Proximate analysis of wheat flour carbohydrates. IV.—Analysis of wholemeal flour and some of its fractions

Abstract

with 500-ml. samples of the grain. An effort was made to arrange for the degree of packing to be similar to that employed in the diffusion experiments. The results in order of increasing air space were maize 41%, wheat 46%, barley 50% and oats 5876 of the total volume occupied by the samples. The rates of diffusion at room temperatures, however, fall in the order of maize, barley, wheat and oats. The reversal of the positions of wheat and barley suggest that factors other than intergranular air space may be involved.In simple systems, where gaseous movement is not complicated by surface adsorption or other factors, the rate of diffusion is inversely proportional to the square root of the density of the diffusing gas. This allows a comparison between the results recorded here for wheat and the results for carbon dioxide reported by earlier workers. Henderson & Oxley give a mean coefficient for carbon dioxide of 0.0415. When corrected for density this indicates a figure of 0.0487 for oxygen, considerably lower than the mean of 0.0670 at 23' reported in the present study. Robertson, who considers that his results might have been affected by slight mass flow through the grain, gave a figure of 0.060 for CO, which, when corrected, indicates a diffusion rate for oxygen as high as 0.0704. The considerable discrepancy observed on comparing the results of Henderson & Oxley with those reported here siiggests, therefore, that factors other than density may have an effect on the diffusion rate. AcknowledgmentsThe author wishes to thank Mr. J. B. McCabe who assisted throughout this investigation, Mr. G. A. McIntyre who carried out the statistical analysis of the results and advised on the experimental method and Mr. L. A. Marshall who drew the diagram.Wholemeal flour and sieved fractions have been examined by methods previously described for the determination of starch, hemicelluloses (including pentosans), sugars and cellulose in wheat flour.', With few minor modifications, they are shown to be applicable also t o samples of commercial bran, endosperm and germ.

Availability to pigs of amino acids in cereal grains

“…In the present experiment, the majority of NDF in wheat w.3~ hemicellulose (69%). Similarly, Fraser & Holmes (1959) found that hemicelluloses were the most abundant carbohydrate in wheat bran, to which they contributed 43% and cellulose 35% of the total carbohydrate.…”

Study of hydration properties of wheat bran as a function of particle size

“…Based on interaction models of cellulose and water for instance, it was predicted that amorphous regions of cellulose are able to bind 3.4 times their own weight in water (Khazraji & Robert, 2013). Considering that approximately 25% of bran consists of cellulose (Fraser & Holmes, 1959;Stone, 2006), a reasonable share of the strongly bound water might in fact be associated with cellulose. Nevertheless, other polysaccharides such as AX and β-glucans also have the potential to strongly bind water in a similar fashion.…”

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

“…Wheat bran a-Linolenic acid (18 : 3n-3): 0·16 g/100 g (548) Reduced glutathione: about 1·7 -19·4 mg/100 g (549) Oxidised glutathione: about 6·1-21·4 mg/100 g (549) Sulfur amino acids: Methionine: 0·20-0·29 g/100 g Lutein: 0·050 -0·180 mg/100 g (571,572) Zeaxanthin: 0·025 -0·219 mg/100 g (571,572) b-Cryptoxanthin: 0·018 -0·064 mg/100 g (571,572) Total phenolic acids: 761 -1384 mg/100 g (533,573) Extractable (free and conjugated) phenolic acids: 46 -63 mg gallic acid equivalents/100 g (574,575) Bound phenolic acids: 148-340 mg gallic acid equivalents/100 g (574,575) Total ferulic acid: 138-631 mg/100 g (154,194,263,264,365,499,533,573,575,576) Free/soluble-conjugated ferulic acid: 1·34 -23·05 mg/100 g (154,194,571,572,574,575,577 -579) Bound ferulic acid: 122 -286 mg/100 g (154,574,575) Total dehydrodiferulic acid: 13-230 mg/100 g (194,533,534,573) Total dehydrotrimer ferulic acid: 15 -25 mg/100 g (533) Total flavonoids: 14·9-40·6 mg/100 g (193) Anthocyanins: 0·9 -48·0 mg/100 g Wheat germ a-Linolenic acid (18 : 3n-3): 0·47 -0·59 mg/100 g (25,548,587) Reduced glutathione: about 19·4-245·7 mg/100 g (549) Oxidised glutathione: about 15·3-122·4 mg/100 g (549) Sulfur amino acids: Methionine: 0·39 -0·58 g/100 g Soluble fibre: 2·1 -6·1 g/100 g (25,482,488) Cellulose: 7·5 g/100 g (550) Hemicellulose: 6·8 g/100 g (550) Lignins: 1·3-1·6 g/100 g…”