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1.
Barley was milled into flours with extraction rates between 100 and 69%. The nutritive value of the flours was studied by chemical analyses and in balance trials with growing rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The protein content in the 69% extraction flour was reduced to 82% of that in whole barley. Lysine (g/16 g N) decreased from 3.30 in whole barley to 2.82 in the most refined flour, however, the biological value was not significantly affected by the degree of milling. The content of minerals was reduced to 40% of that in whole barley, but only rats fed refined flours were able to maintain their femur zinc concentration. Factors present in the outer part of the kernel interfere strongly with utilization of zinc; and it appears that phytate is not solely responsible for the adverse effects on zinc utilization. In rats fed whole barley, femur zinc could be maintained and protein utilization improved by zinc supplementation. It could be concluded that unless barley is milled into refined products, or zinc is supplied from external sources, zinc utilization is adversely affected and protein utilization is limited by a poor zinc status.  相似文献   

2.
Different grades of maize flour were produced by dry milling of yellow maize. The chemical composition of wholemeal, three semi-sifted flours and degermed maize was determined, and the nutritional value of the flours were investigated in balance experiments with growing rats. Distinct differences in nutrient and fibre content were found. Amino acid composition was significantly different in the milled fractions, and the content of minerals and phytate in the flours was determined by the extent to which the germ was retained. Phytate: zinc molar ratios ranged from 43 to 2. Weight gain of rats was closely correlated to the concentration of lysine (r=0.99) and tryptophan (r=0.97). Weight gain of rats fed degermed maize was reduced to half of that of rats fed wholemeal. True protein digestibility was high, but protein quality varied widely between the different flour fractions. Energy density of the flours was quite similar. Rats fed wholemeal had the highest intake of zinc and the highest apparent zinc absorption and retention but the lowest femur zinc concentration. Factors present in whole maize may interfere with zinc utilization. The results might indicate an interaction between phytate and fibre. Supplementation of wholemeal with lysine and tryptophan increased the biological value of the protein and the weight gain considerably, but apparent absorption and retention of zinc as well as femur zinc concentration were similar in unsupplemented and supplemented rats. The percentage of zinc absorbed from degermed maize flour was high, but degermed maize has a very low content of minerals and is highly deficient in lysine and tryptophan.  相似文献   

3.
Rye was milled into flours having extraction rates between 100 and 65%. The nutritive value of the various fractions was studied by chemical analyses and in balance trials with rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The lysine content (g/16 g N) was 4.23 in whole rye, but only 3.76 in the 65% extraction flour, and a corresponding reduction in biological value was found. A reduction of 50% or more was observed for several minerals with zinc and phosphorus being most affected. The apparent zinc absorption and retention expressed in absolute values, were significantly higher from the flours of high extraction than from the more refined flours, in spite of a much higher phytate content in whole rye and lightly milled flours. It could be concluded that milling of rye into highly refined flours not only preclude considerable amounts of nutrients from human consumption, but the remaining flours have a much poorer nutritive value than flour made from whole rye.  相似文献   

4.
Wheat was milled into flours having extraction rates between 100 and 66%. The nutritive value of the various fractions was studied by chemical analyses and in balance trials with rats. The concentration of essential nutrients decreased when the extraction rate was lowered. The lysine content (g/16 g N) e.g. was 2.52 in whole wheat, but only 2.18 in the 66% extraction flour; however, only a slight reduction in biological value was found. The content of minerals was reduced to 30% of that in whole wheat, and the apparent zinc absorption and retention expressed in absolute values, were significantly higher from the flours of high extraction than from the more refined flours, in spite of a much higher phytate content in whole wheat and lightly milled flours. It could be concluded that milling of wheat into highly refined flours not only preclude considerable amounts of nutrients from human consumption, but the remaining flours have a much poorer nutritive value than flour made from whole wheat.  相似文献   

5.
Finger millet and sorghum flours were used as vehicles for double fortification with ferrous fumarate, zinc stearate and EDTA. The iron and zinc salts were added at levels that provided 60 mg iron and 50 mg zinc per kg of flour. EDTA was added at levels equimolar to the added iron. The double-fortified finger millet and sorghum flours contained bioaccessible zinc contents of 0.83 and 1.63 mg/100 g, respectively, while the respective bioaccessible iron contents were 2.39 and 2.63 mg/100 g. The exogenous iron and zinc did not mutually interfere with their bioaccessibility. The shelf-life of the fortified flours was also satisfactory up to a period of 60 days, as indicated by the moisture and free fatty acid contents in the fortified flours. Double fortification of the millet flours did not negatively alter the sensory quality of the products prepared from them. The RDA for iron and zinc of Indian children, women and men can be sufficiently met with approximately 4 dumplings or 9 rotis. The use of such qualitatively and quantitatively rich flours can be promoted through welfare programs to reduce and subsequently eradicate iron and zinc deficiency.  相似文献   

6.
Potential use of the high protein by-product of beer production from 77% sorghum malt and 23% maize grit was investigated. Red sorghum spent grains (RSSG) and white sorghum spent grains (WSSG) contained 23.4 and 19.3% crude protein (CP), 54 and 43% dietary fiber (NDF), 1.44 and 0.78% ash, 4.5 and 3.2% hexane extract and tannin content of 7.5 and 1.0 mg/g catechin equivalent respectively. Magnesium was the most abundant mineral in both RSSG and WSSG — 185 and 140 mg/kg, respectively. Calcium, zinc, iron and copper were generally low. Both samples contained cadmium 1.12 (WSSG), 1.19 (RSSG) and lead at 1.38 mg/kg. Lysine was the limiting amino acid (chemical score 0.55) in both samples. Other essential amino acids were adequate or surplus. Stearic acid was the predominant fatty acid with varying levels of lauric, myristic, palmitic, and oleic acids in both samples. Feed intake and weight gain were highest in rats fed 26.3% WSSG (contributing 50% of the diet protein) but protein efficiency ratio (PER) and net protein retention (NPR) were highest in diets where spent grains contributed just 25% of the diet protein. True digestibility of diets decreased as dietary fiber content increased such that animals on diets containing 100% spent grain protein (above 20% NDF) lost weight.  相似文献   

7.
White and brown ragi (Eleusine coracana) varieties were analysed for tannin, phytate phosphorus, total phosphorus, iron, ionisable iron, zinc and soluble zinc content. White ragi had no detectable tannin while in brown varieties it ranged from 351 to 2392 mg per 100 g. Germination brought about a progressive decrease in tannin and phytate phosphorus and an increase in ionisable ion and soluble zinc content of grain ragi. Both in raw and germinated grain, ionizable iron was significantly higher in white than in brown varieties. While ionisable iron was inversely correlated with the level of tannin and phytate phosphorus, soluble zinc was negatively correlated with phytate phosphorus. After extraction of tannin, ionisable iron of brown ragi rose by 85%. On the other hand, in white varieties, addition of tannin extracted from brown ragi, resulted in a 52–65% decrease in ionisable iron content. These studies indicated that poor iron availability in ragi as judged by its low ionisable iron content was due to the presence of tannin in the grain.  相似文献   

8.
The effects of germination, extraction (double extraction with 70% ethanol and water at isoelectric point) and -amylase treatments of chick pea seed flours on crude protein, total carbohydrate, protein efficiency ratio (PER), biological value (BV), true digestibility (TD), net protein utilization (NPU), essential amino acid composition, in-vitro protein digestibility (IVPD) and actual amino acid indices (essential amino acid index or amino acid score) were evaluated. Crude protein content was increased (8–149%), while total carbohydrate was decreased (11–62%) by germination, extraction and -amylase treatments. Alpha-amylase treatment was more efficient in reducing total carbohydrate and increasing the protein content than that of extraction treatment. The protein quality of chick pea flours as measured by PER, BV, TD, NPU, IVPD and corrected amino acid indices (actual amino acid indices×IVPD) was significantly improved by these treatments. The protein quality of germinated--amylase treatment was comparble with casein, while germinated--amylase treaded seeds appeared nutritionally superior to casein. The results indicate that the germinated--amylase and germinated--amylase-extracted treatments could be used successfully as a source of concentrated high quality protein for baby food production. The corrected amino acid indices gave better prediction of PER, BV, TD and NPU (r=93 to 97) than actual amino acid indices (r=45 to 71). PER was highly correlated with corrected amino acid score (r=0.93). The PER could be predicted from the following simple regression equation: PER=–1.827+0.0561×corrected amino acid score.  相似文献   

9.
Coeliac patients suffer from an immune mediated disease, triggered by the ingestion of a protein composite (gluten) found in wheat, rye and barley. Consequently, there is a need for products such as bread or pasta, made from alternative cereal grains or pseudocereals. A fair proportion of the gluten free products currently on the market are nutritionally inadequate. Hence, it was the aim of this study to investigate the nutrient composition of seven commonly used commercial gluten free flours (oat, rice, sorghum, maize, teff, buckwheat and quinoa) and compare them to wheat and wholemeal wheat flour. In addition to the levels of all major compounds, also mineral composition, fatty acid profile, phytate, polyphenols and folate content were determined. Furthermore, properties of carbohydrates were studied in greater detail, looking at total and damaged starch levels; total, soluble and insoluble dietary fibre content as well as amylose/amylopectin ratio. Proteins were further investigated by means of capillary electrophoreses. Additionally, the ultra-structure of these materials was explored using scanning electron microscopy. The results show that maize and rice flour are poor regarding their nutritional value (low protein, fibre, folate contents). In contrast, teff as well as the pseudocereals quinoa and buckwheat show a favourable fatty acid composition and are high in protein and folate. In particular, quinoa and teff are characterised by high fibre content and are high in calcium, magnesium and iron. Therefore these flours represent nutrient-dense raw materials for the production of gluten free foods.  相似文献   

10.
Sorghum, pearl millet, and finger millet flours (60% of each) were blended with toasted mung bean flour (30%) and nonfat dry milk (10%) and extruded (Brabender single screw) to make precooked, ready-to-eat, weaning foods. The extruded foods had high cold paste viscosity, but their cooked paste viscosity was lower than that of the respective blends. Chemical scores of the extruded foods were 78 for sorghum, 80 for pearl millet, and 96 for finger millet. Protein digstibility corrected amino acid scores (PD-CAS) were similar for pearl millet (68%) and finger millet (69%); PD-CAS for sorghum was 57%. Total dietary fiber content of the foods ranged from 7.6 to 10.1%, with the soluble dietary fiber content of the foods being about 10% higher than that of the corresponding blends. Extrusion enhanced the in vitro protein digestibility of foods, but no marked difference occurred in the in vitro carbohydrate digestibility among the unprocessed blends and the extruded foods. The net protein ratio, protein efficiency ratio, and biological values were higher for the finger millet food than for the pearl millet food, probably because of the higher lysine content of the finger millet protein.Contribution No. 95-253-J of the Kansas Agricultural Experiment Station.  相似文献   

11.
The effects of endosperm vitreousness, cooking time and temperature on sorghum and maize starch digestion in vitro were studied using floury and vitreous endosperm flours. Starch digestion was significantly higher in floury sorghum endosperm than vitreous endosperm, but similar floury and vitreous endosperm of maize. Cooking with 2-mercaptoethanol increased starch digestion in both sorghum and maize, but more with sorghum, and more with vitreous endosperm flours. Increasing cooking time progressively reduced starch digestion in vitreous sorghum endosperm but improved digestibility in the other flours. Pressure-cooking increased starch digestion in all flours, but markedly more in vitreous sorghum flour; probably through physical disruption of the protein matrix enveloping the starch. Irrespective of vitreousness or cooking condition, the alpha-amylase kinetic constant (k) for both sorghum and maize flours remained similar, indicating that differences in their starch digestion were due to factors extrinsic to the starches. SDS-PAGE indicated that the higher proportion of disulphide bond-cross-linked prolamin proteins and more extensive polymerisation of the prolamins on cooking, resulting in polymers of Mr>100k, were responsible for the lower starch digestibility of the vitreous sorghum endosperm flour.  相似文献   

12.
Brown and milled rices were prepared from rough rice, and the nutritive value of the rices was studied by chemical analyses and in balance experiments with growing rats. The concentration of essential nutrients decreased with the degree of milling, but the energy density of brown and milled rices was similar. In the highly refined white rice the protein content was reduced to 86% and the mineral content to 23% of corresponding levels in brown rice. The zinc concentration was halved. The amino acid composition was rather unaffected by the degree of milling, but the lysine concentration was slightly lower in white rice than in brown rice. Milling was accompanied by an increase in true protein digestibility and a corresponding decrease in biological value. Thus net protein utilization of the different rices was remarkably uniform. A total of 33% of the utilizable protein and 22% of the digestible energy in brown rice was removed during milling. Rats fed rough, brown and lightly milled rices were unable to maintain their femur zinc concentration; deposition of calcium and phosphorus also appeared to be affected. Factors present in the outer part of the rice kernel interfere strongly with zinc utilization. Phytate and/or fibre are not solely responsible for this effect. Unless rice was milled into highly refined white rice, zinc status of rats was adversely affected. The results suggest that zinc might be a limiting factor in rice-based diets.  相似文献   

13.
The present study was carried out to develop papads from wheat and legume blends and to analyze them for organoleptic acceptability, nutritional quality, and keeping quality. Papad is a dehydrated product prepared from dhals or rice. A firm but pliable dough is made from the flours of dhals or rice with addition of suitable seasoning. It is shaped into balls, rolled out thin, dried and toasted over open fire so as to give a light, crisp product. Mung flour papads were kept as control and wheat flour, chickpea flour, and pea flour were used to supplement mung flour papads. Three different proportions (10, 20, 30%) of each flour were used to supplement Mung flour. Papads with wheat flour (10%), chickpea flour (20%), and pea flour (10%) level of supplementation were found to be most acceptable and these papads were subjected to nutritional evaluation. Protein content significantly increased on supplementation with legume flours at all levels. Fat content was significantly higher in chickpea flour supplemented papads. Ash content varied significantly from 10.17 to 10.78% in papads. Total carbohydrates decreased significantly on supplementation with chickpea flour. Copper content increased significantly on supplementation. A significant decrease in phytic acid and trypsin inhibitor of supplemented papads was found. In vitro protein digestibility significantly increased on supplementation but a significant decrease in in vitro starch digestibility was found in supplemented papads. Storage studies showed that chickpea flour and pea flour supplemented papads can be stored safely for 60 days and wheat flour supplemented papads for 30 days both at room and refrigeration temperatures.  相似文献   

14.
There is considerable interest in sorghum, millets and pseudocereals for their phytochemical content, their nutritional potential and their use in gluten-free products. They are generally rich in a several phenolic phytochemicals. Research has indicated that the phenolics in these grains may have several important health-promoting properties: prevention and reduction of oxidative stress, anti-cancer, anti-diabetic, anti-inflammatory, anti-hypertensive and cardiovascular disease prevention. However, increased research on the actual health-promoting properties of foods made from these grains is required. Biofortified (macro and micronutrient enhanced) sorghum and millets are being developed through conventional breeding and recombinant DNA technology to combat malnutrition in developing countries. Enhanced nutritional traits include: high amylopectin, high lysine, improved protein digestibility, provitamin A rich, high iron and zinc, and improved mineral bioavailability through phytate reduction. Some of these biofortified cereals also have good agronomic characteristics and useful commercial end-use attributes, which will be important to their adoption by farmers. Knowledge of the structure of their storage proteins is increasing. Drawing on research concerning maize zein, which shows that it can produce a visco-elastic wheat-like dough, it appears that the storage proteins of these minor grains also have this potential. Manipulation of protein β-sheet structure seems critical in this regard.  相似文献   

15.
The nutrient composition of eight multimixesformulated for use as complementary foods fromprocessed soybeans, cowpeas, maize, sorghum, yams,cocoyams, plantains and sweet potatoes were examined. The foods were processed by sprouting, cooking andfermentation. The samples were separately dried andmilled to fine flours. A ratio of 65% cereal, 30%legume and 5% starchy staple (65:30:5) calculated ona protein basis was used to formulate the multimixes. The blends were chemically analyzed using standardprocedures. The mixtures containing soybeans hadhigher protein, lipid, energy, crude fiber and calciumlevels but lower carbohydrate content than thosemixtures without soybean. The protein and energylevels of the multimixes were higher than those ofsome commercial infant foods (Cerelac, Farex andNestrum) in Nigeria but were comparable to that of`soy-ogi'. The multimixes contained fair quantitiesof calcium and phosphorus and an adequate amount ofsome of the essential amino acids. Methionine was themost limiting amino acid in all the mixtures. Blending cowpeas with maize produced a higher proteinscore than blending cowpeas or soybeans with sorghum. The cowpea/maize/sweet potato mixture had the highestprotein score.  相似文献   

16.
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17.
The changes in proximate composition, phytate phosphorus, thiamine and ascorbic acid content of finger millet, pearl millet and foxtail millet during progressive germination were studied. Germination resulted in a slight decrease in total protein and minerals, a marked fall in phytate-phosphorus and a significant increase in the ascorbic acid content of the millets. An increase in lysine and tryptophan but no appreciable changes in threonine and sulfur amino acid content of the millets were observed as a result of germination. However, the protein efficiency ratio values of ungerminated control seeds, 48 h germinated green malt and kilned malt were not significantly different.  相似文献   

18.
The effects of cowpea and amino acid supplementation on the protein quality and chemical characteristics of a maize-based West African traditional weaning food were studied. Process optimization for improved nutritive value was also determined. Supplementation of the traditional weaning food with cowpea increased the lysine, tryptophan and threonine content while the sulphur-amino acids decreased with increasing levels of cowpea. Further supplementation of 70:30 maize/cowpea blends with lysine, threonine or methionine did not significantly improve (p>0.05) protein quality in terms of the biological value (BV) and net protein utilization (NPU), although significant increases in the protein scores were noted. However, considerable improvements in the BV and NPU were recorded in blends fortified with either tryptophan alone or a combination of lysine, tryptophan, methionine and threonine. Cooking whole cowpea seeds for 45 min before incorporating in the blend formulation also significantly improved (p<0.05) the protein quality of maize/cowpea blends. The BV and NPU of blends containing 30% pre-cooked cowpea increased from 52 to 76% and 50 to 71% respectively compared to pure maize porridge. The protein content increased from 10 to 14% and the utilizable proteins more than doubled. The weight increase of experimental rats fed with these blends was comparable to that of rats on casein diet. A 30% supplementation of the maize-based weaning food with cowpea therefore greatly enhances the nutritive value especially when the cowpea is pre-cooked for 45 min. Use of chemical scores alone for such blends cannot be a reliable index of blend quality.  相似文献   

19.
The chemical, sensory and rheological properties of porridges made from blends of sprouted sorghum, bambara groundnuts and fermented sweet potatoes were examined. Sorghum and bambara groundnuts were sprouted for 48 h while sweet potatoes were fermented for the same period. Blends were formulated from the processed ingredients in the ratio of 60:40:0, 57:42:1, 55:44:1 and 52:46:2 (protein basis) of sorghum, bambara groundnuts and sweet potatoes. Porridges were prepared from the composite flours and the traditional sorghum complementary food. Standard assay methods were used to evaluate the flours for nutrient composition. The porridges were also tested for sensory properties and viscosity. Processing increased the levels of most of the nutrients evaluated. Relative to the sorghum traditional complementary food, thecomposite flours had higher levels of lipids, protein, ash, crude fiber and minerals (p<0.05). The porridges from the composite flours were generally liked slightly by the panelists and were about seven times less viscous than the porridge from the traditional sorghum complementary food. Use of the composite flours, particularly the 52:46:2 blend, as a traditional complementary food should be encouraged in Nigeria especially with the increasing cost of commercial complementary foods.  相似文献   

20.
Pearl millet was decorticated to obtain a bran rich and endosperm rich fraction. The two fractions were soaked in solutions with varying pH. Pearl millet grains were germinated and steamed followed by decortication to obtain two fractions. It was observed that bran rich fractions contained high concentrations of iron, zinc, polyphenols, phytic acid, fibre and flavonoids. Soaking for short duration of 3 h did not result in major mineral losses but decreased the inhibitory factors which depended on the pH. Alkaline soaking decreased flavonoid content by 62.7% in the endosperm rich fraction, while acidic soaking decreased phytic acid content to the maximum in the bran rich fraction. Combination of treatments like germination and heat decreased the phytate content to the maximum in the endosperm rich fraction. Acidic conditions improved zinc bioaccessibility in the bran rich fraction (35%) and iron bioaccessibility (2.5%) in the endosperm rich fraction. Bran rich fraction from germinated grain also had enhanced bioaccessibility of both the minerals but comparatively lesser when compared to soaking under acidic conditions. Soaking the grain components under slightly less than neutral conditions also decreased some of the inhibitory factors and improved the zinc bioaccessibility to some extent in the bran rich fraction.  相似文献   

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