Assessment of pearl millet vs rice based diets for bioavailability of four trace metals

Cereals including millets are consumed in India as a staple with wide variety of pulses and vegetables in varying proportions. Trace mineral contents of pearl millet are two to ten times higher than that of rice. Comparative performance of pearl millet based (PM) diets as against rice based (RB) diets in terms of trace mineral bioavailability was studied, based on the prevailing dietary patterns in India. In vitro percent dialysability of zinc, iron, copper and manganese under simulated gastrointestinal conditions was considered as indicator of metal bioavailability. Dialysable zinc and iron were estimated using 65 Zn and 59 Fe as tracers, while dialysable copper and manganese were measured by Atomic absorption spectrophotometer for 20 food items and 15 RB and 17 PM diets prepared from these items. Results indicated that percent dialysability of zinc and copper was higher for RB diets than PM diets, while that of iron and manganese were comparable. Total dialysable iron, copper and manganese in PM diet was 2 to 4 times higher than RB diet.     

Phytate and mineral elements concentration in a collection of Italian durum wheat cultivars

Mineral deficiencies are prevalent in human populations and the improvement of the mineral content in cereal products represents a possible strategy to increase the human mineral intake. Nevertheless, most of the inorganic phosphorus (P_i) present in mature cereal seeds (40–80%) is stored as phytate, an anti-nutritional factor that forms complexes with minerals such as Ca, Mg, Zn and Fe reducing their bioavailability. The present study was undertaken: (i) to determine the variation in phytate and mineral concentrations in the whole grains of 84 Italian durum wheat (Triticum durum Desf.) cultivars representative of old and modern germplasm; (ii) to estimate the magnitude of genotype × environment interaction effects; and (iii) to examine the interrelationships among mineral concentrations in durum wheat with the final aim to identify superior durum wheat cultivars that possess low phytate content and high concentration of mineral elements in their whole-wheat flour. The cultivars were grown in field trials during 2004–2005 at Foggia, Italy and during 2005–2006 at Foggia and Fiorenzuola d’Arda—Southern and Northern Italy. The phytate content was estimated indirectly by using a microtitre plate assay evaluating the P_i absorbance at 820 nm, while the Cu, Fe, Mn, Ca, K, Mg, Na and Zn mineral contents were determined by ICP/OES. The contents of Zn and Fe across years and locations ranged from 28.5 to 46.3 mg/kg for Zn with an average of 37.4 mg/kg and from 33.6 to 65.6 mg/kg for Fe with an average of 49.6 mg/kg. P_i grain content was between 0.46 and 0.76 mg/g showing a positive correlation with all minerals except Cu and Zn. Although breeding activity for Fe and Zn would be difficult because G × E interaction is prevalent, multi-location evaluation of germplasm collection help to identify superior genotypes to achieve this objective. The results here reported open the possibility of designing a specific breeding program for improving the nutritional value of durum wheat through the identification of parental lines with low-P_i and high minerals concentration in whole grains.     

Double fortification of sorghum (Sorghum bicolor L. Moench) and finger millet (Eleucine coracana L. Gaertn) flours with iron and zinc

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.     

Phytase activity, phytate, iron, and zinc contents in wheat pearling fractions and their variation across production locations

Pearling is an effective method for evaluating the distribution of chemical components in wheat grain. Twelve pearling fractions (P₁–P₁₂) of wheat grain were obtained using two rice polishers for 10 cultivars (six soft red wheats and four hard white wheats) grown at two locations with different environmental conditions in Jiangsu Province, China. The results show that the effects of cultivar, location, and pearling on wheat flour phytase activity, phytate, iron, and zinc contents were all significant, with pearling having the greatest effect. All the four components showed a diminishing trend as pearling progressed from the outer layers to the inner part of wheat grain. Generally, the P₂ fraction (the outer 4–8% layer of wheat grain) had the highest phytase activity and phytate and iron contents, whereas the P₁ fraction (the outer 0–4% layer) ranked the highest for zinc content. Growing location had a large influence on grain phytase, phytate, and iron, but the differences between locations decreased as pearling level increased.     

Importance of seed-borne fungi of sorghum and pearl millet in Burkina Faso and their control using plant extracts

Seed-borne fungi of sorghum and pearl millet in Burkina Faso were surveyed. A total of 188 seed samples from various locations, collected in 1989 (42) and 2002 (146), were tested, using the blotter, dry inspection and washing methods. Infection experiments were carried out with the major fungi recorded on each crop by the blotter test. Six essential oils of plants were investigated for their inhibitory activity against eight pathogenic fungi. Thirty four and 27 fungal species were found in seed samples of sorghum and pearl millet, respectively. Phoma sp. and Fusarium moniliforme infected 95 to 100% of the seed samples of both sorghum and pearl millet. Sphacelotheca sorghi and Tolyposporium ehrenbergii were encountered in respectively, 75 and 33% of seed samples of sorghum. T. penicillariae, Sclerospora graminicola and Claviceps fusiformis were present in 88, 41 and 32% of seed samples of pearl millet, respectively. Seeds inoculated with Acremonium strictum, Curvularia oryzae, F. equiseti, F. moniliforme and F. subglutinans and sown in sterilized soil, showed considerable mortality of the seedlings. Three essential oils inhibited in vitro the mycelial growth of all the fungi used by 85 to 100% and reduced significantly sorghum and pearl millet seed infection rates of Phoma sp., Fusarium sp., Curvularia sp., Colletotrichum graminicola and Exserohilum sp. Presence of many pathogenic fungi in considerable number of seed samples indicates the need of field surveys for these and other pathogens. Development of plant extracts for the control of seed-borne pathogens and public awareness on seed-borne diseases management measures for maintaining quality seed should be increased.     

Physical and nutritional qualities of extruded weaning foods containing sorghum,pearl millet,or finger millet blended with mung beans and nonfat dried milk

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.     

Adaptation of sorghum/maize and sorghum/pearl millet intercrop systems to the toposequence land types in the North Sudanian zone of the west African Savanna

Cereal/cereal intercrop systems are commonly used by farmers in the higher-rainfall areas of the South Sudanian and Guinean savanna zones of West Africa. Towards the North Sudanian zone these systems become less common, because of a shorter rainy season with a more abrupt start and end. However, previous work on the responses of maize (Zea mays), sorghum (Sorghum bicolor), and pearl millet (Pennisetum americanum) crops to the different toposequence land types indicated that crop mixtures of sorghum/millet for uplands and sorghum/maize for lowlands would be less prone to drought stress and waterlogging risks than would the respective sole crops.The present studies showed consistent intercropping advantages of at least 25% for sorghum/maize systems when both crops are sown at the same time. The relative advantages from this system were greatest for the uplands.Intercropping advantages were generally less for the sorghum/millet systems, and it proved essential to delay the millet sowing to prevent serious competition to the sorghum. Sorghum/millet intercropping provides a risk-reducing alternative to sole cropping, because sorghum plants lost during the common early droughts can be replaced by an early-maturing millet sown in July. However, because of the unpredictability of the early-season rainfall, sorghum/millet systems will be difficult to standardize; both the sowing date and the plant densities of the component crops may require adjustments each year in response to the starting date of the rains and the extent to which the sorghum has survived the early-season droughts.     

Global status of nematode problems of groundnut, pigeonpea, chickpea, sorghum and pearl millet, and suggestions for future work

Analysis of responses received from 40 cooperators in 20 countries to a questionnaire on nematode problems of groundnut, pigeonpea, chickpea, sorghum and pearl millet suggested that Meloidogyne spp. are internationally important nematode pests of groundnut, chickpea and pigeonpea. Pratylenchus spp. are important on all the five crops. In India, Heterodera cajani and Rotylenchulus reniformis are important pathogens of pigeonpea. Over the last 10–15 years, extensive nematode disease surveys have been undertaken for these crops in Australia, Egypt, India, Jamaica, Senegal, Sudan, Thailand and Zimbabwe; however, < 10% of the total crop areas were covered by these surveys. Except for Brazil, Egypt, USA and Zimbabwe, growers do not use nematicides to control the nematodes. Cultural practices, especially crop rotations, are the most commonly used control measures. Species of Meloidogyne, Pratylenchus and Rotylenchulus on the legumes, and species of Hoplolaimus, Pratylenchus, Quinisulcius and Xiphinema on the cereals, are strongly suspected of increasing the severity of fungal diseases. Work aimed at finding host resistance is being done in Brazil, Fiji, India and the USA, and some sources of resistance have been identified against Meloidogyne arenaria, M. incognita, M. javanica and R. reniformis. Facilities for resistance screening work now exist in many countries. Information on damage thresholds of important pest species are available only from Brazil, Fiji, India and the USA.     

Effects of seed treatments and storage on the changes in lipids of pearl millet meal

Lipids in pearl millet meal showed a rapid hydrolytic decomposition during storage. The magnitude of such degradation was influenced significantly by the nature of the storage container used, the temperature and heat treatments given to the seeds. The hydrolytic breakdown of lipids was significantly low in the meals stored in polyethylene bags, plastic boxes and under refrigerated (5±2 °C) conditions. Hot water blanching at 98 °C for 10 sec and dry heating of seeds at 100 °C for 120 min were found to be most effective in minimising the undesirable changes in lipids of the meal during storage.     

Changes in the carbohydrates and nitrogenous components during germination of proso millet,Panicum miliaceum

Since germination has been found to increase the nutritive qualities of grains, proso millet, a minor millet, was allowed to germinate for 1–7 days and analysed for protein fractions, free amino acids, lysine, tryptophan, methionine, non-protein nitrogen, starch, and sugars. Overnight soaking and germination up to 7 days significantly increased the free amino acids and total sugars while the content of dry weight and starch decreased. Increases in albumin and globulin and large decreases in prolamin accompanied sprouting. The percent protein in germinated grains was higher than in the initial grain as a result of dry matter loss during germination. Further, there was an increase in lysine, tryptophan and non-protein nitrogen contents during germination. No change was noticed in methionine content.     

Effect of different soaking conditions on inhibitory factors and bioaccessibility of iron and zinc in pearl millet

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.     

小麦铁锌营养品质研究进展

"隐性饥饿",即铁、锌等微量元素缺乏症,已成为困扰我国居民的首要营养不良问题.选育高铁、锌含量、强植酸酶活性或低植酸含量的"微量营养强化型"小麦品种对于改善我国西部居民的营养状况具有重要的意义.本文主要介绍小麦铁锌营养品质的遗传改良研究进展,包括铁锌营养品质的相关化学组分(铁、锌、植酸和植酸酶)及改善小麦铁锌营养品质的遗传途径等两方面,并指出了小麦铁锌营养品质的研究方向和工作重点.     

Changes in mass and chemical composition of grass roots during decomposition

The decomposition of dead roots of perennial grasses was examined in nylon litter bags not containing soil at two soil depths, 10 and 20 cm, and also in larger nylon bags containing soil at 020 cm depth. Bags were sampled three times during the growing season to determine weights of organic matter, crude protein, Klason lignin and non-structural and structural carbohydrates.
From 3 July to 5 October (94 days) the litter bags at 10 and 20 cm and the nylon bags lost, respectively, 35,38 and 65% of their organic mass of particle size < 1 mm.
Non-structural carbohydrates constituted 6% of the organic matter in the original sample but only 1% or less during the sampling period. Klason lignin increased from 22 to 29% and crude protein from 8 to 10% of the remaining organic matter, whereas structural carbohydrates changed very little.
The constituents were degraded at different rates. The non-structural carbohydrates had decomposed almost completely by the first sampling and of the other constituents the structural carbohydrates were degraded most rapidly. Before the first sampling unexpected amounts of structural carbohydrates, particularly glucans, had disappeared.
The results help to explain rapid declines in root mass (up to 50%) during summer in perennial grass leys observed in earlier experiments.     

Levels of antinutritional factors in pearl millet as affected by processing treatments and various types of fermentation

Pearl millet (Pennisetum typhoideum) was fermented with Lactobacilli or yeasts alone and in combination, and with natural microflora after various processing treatments, as grinding, soaking, debranning, dry heat treatment, autoclaving and germination. Fermentation was carried out at 30°C for 48 hours withLactobacillus plantarum (LP) andRhodotorula (R) isolated from naturally fermented pearl millet andLactobacillus acidophilus (LA),Candida utilis (CU) and natural microflora (NF). Germination and autoclaving, and debranning and autoclaving were the most effective processing treatments to reduce the phytic acid, amylase inhibitors and polyphenols. There was a further reduction in these antinutrients due to fermentation. Phytic acid and amylase inhibitors were completely eliminated after fermentation in some of the samples especially in soaked, debranned and germinated ones. Polyphenols were altered non-significantly in general but fermentation with Lp+R and NF caused a significant increased in polyphenols.     

Effect of drought and elevated temperature on grain zinc and iron concentrations in CIMMYT spring wheat

Abiotic stress caused by increasing temperature and drought is a major limiting factor for wheat productivity around the world. Wheat plays an important role in feeding the world, but climate change threatens its future harvest and nutritional quality. In this study, grain iron (Fe) and zinc (Zn) concentrations of 54 wheat varieties, including CIMMYT derived historic and modern wheat varieties grown in six different environmental conditions, were analyzed. The objective of the study was to evaluate the effect of water and heat stress on the nutritional value of wheat grains with a main emphasis on grain protein content, Zn and Fe concentrations. Significant effects of environment on protein content and grain micronutrients concentration were observed. The protein and Zn concentrations increased in the water and heat stressed environments, whereas Zn and Fe yield per unit area was higher in non-stress conditions. The results suggest that genetic gains in the yield potential of CIMMYT derived wheat varieties have tended to reduce grain Zn, in some instances; however, environmental variability might influence the extent to which this effect manifests itself.     

Improved nitrogen status enhances zinc and iron concentrations both in the whole grain and the endosperm fraction of wheat

This study was conducted to assess the role of increasing N supply in enrichment of whole grain and grain fractions, particularly the endosperm, with Zn and Fe in wheat. The endosperm is the most widely consumed part of wheat grain in many countries. Plants were grown in the greenhouse with different soil applications of N and Zn and with or without foliar Zn spray. Whole grain and grain fractions were analyzed for N, P, Zn and Fe. Increased N supply significantly enhanced the Zn and Fe concentrations in all grain fractions. In the case of high Zn supply, increasing N application enhanced the whole grain Zn concentration by up to 50% and the endosperm Zn by over 80%. Depending on foliar Zn supply, high N elevated the endosperm Fe concentration up to 100%. High N also generally decreased the P/Zn and P/Fe molar ratios in whole grain and endosperm. The results demonstrate that improved N nutrition, especially when combined with foliar Zn treatment, is effective in increasing Zn and Fe of the whole grain and particularly the endosperm fraction, at least in the greenhouse, and might be a promising strategy for tackling micronutrient deficiencies in countries where white flour is extensively consumed.     

Heritability and quantitative trait loci of composition and structural characteristics in sorghum grain

Breeding efforts in cereal crops directed toward developing or improving end-use products of grain require assessment of existing phenotypic variance and an understanding of the genetic control of grain quality traits. To this end, a grain sorghum [Sorghum bicolor (L.) Moench] mapping population consisting of 113 F_2:7 recombinant inbred lines (RILs) derived from a cross between Sureño and RTx430 was evaluated in multiple environments for grain composition (fat, fiber, protein, starch) using near-infrared reflectance spectroscopy (NIRS), and size estimates of grain parts (embryo, vitreous endosperm, floury endosperm, kernel area) using an image-based phenotyping software system. Estimates of broad-sense heritability of grain compositional traits ranged from 0.11 to 0.90, whereas those of grain size ranged from 0.16 to 0.72. Composite interval mapping (CIM) was applied to a single nucleotide polymorphism (SNP)-based linkage map to identify marker-trait associations, and through these efforts, a total of 37 quantitative trait loci (QTL) for grain quality were identified across environments. Each QTL explained between 7 and 23% of the phenotypic variation for a given grain trait. Three of the five QTL that colocalized were for traits with significant negative correlation, which included grain protein content that was negatively correlated with grain starch content. In addition, several traits that were positively correlated (e.g. fat and fiber content) also revealed colocalized QTL. Finally, we compared the present study with previous studies identifying grain composition trait loci in an effort to identify genomic regions controlling grain traits across a diversity of environments and sorghum genotypes.     

Fermentation of pearl millet flour with yeasts and lactobacilli:in vitro digestibility and utilisation of fermented flour for weaning mixtures

Single as well as mixed culture fermentations by yeasts (S. diastaticus;S. cerevistiae) and lactobacilli (L. brevis;L. fermentum) at 30 °C for 72 h improved the starch and protein digestibility (in vitro) of pearl millet flour significantly. The flour fermented bySaccharomyces diastaticus, a starch hydrolysing yeast, had the highest starch digestibility whereas fermentation bySaccharomyces cerevisiae enhanced the in vitro protein digestibility of the flour significantly. Weaning mixtures prepared from the fermented flour were also found to be organoleptically acceptable.     

Changes in chemical composition,minerals and amino acids during seed growth and development of four safflower cultivars

Investigation of four safflower ( Carthamus tinctorius L.) cultivars (S208, S400, S541 and S303) showed that when the seeds were harvested at different stages of growth and development (10, 20, 30, and 40 days) after flowering, moisture content significantly decreased with time. Oil, protein, ash and crude fiber were increased up to day 30. Thereafter, these parameters started to decline gradually with time. The cultivars differed in their final values; oil content of the seeds varied from 10.90 to 45.40%, moisture varied from 4.20 to 8.10% and from 8.50 to 11.10%, protein from 12.10 to 20.30% and from 13.40 to 29.60%, ash from 2.30 to 5.40% and from 2.80 to 6.50%, for the seeds and defatted meal, respectively. Crude fiber for the defatted meal was found to vary from 29.50 to 38.60%. Carbohydrate for all cultivars decreased rapidly up to day 40 with final values varying from 28.10 to 63.30% and from 56.70 to 70.30% for the seeds and defatted meal, respectively. Mineral content (Cu, Zn, Fe, Mg, Mn) fluctuated while phosphorus content significantly increased with time for all cultivars. Amino acid content of the defatted meal increased with time up to day 30 after which it started to decline gradually for all cultivars.     

Insights from in vitro exploration of factors influencing iron,zinc and provitamin A carotenoid bioaccessibility and intestinal absorption from cereals

Developments in genetics, agronomics and processing has positioned staple cereals as important sources of iron, zinc and provitamin A (pVA) carotenoids for nutritionally vulnerable populations. Significant effort has been placed on understanding the bioavailability of these micronutrients from cereal foods, including the exploration of underlying mechanisms by which their bioavailability can be modified. While micronutrient bioavailability is preferably assessed in clinical trials, relevant in vitro digestion and intestinal cell culture models have been applied to study effects of genetic, agronomic, post-harvest and food processing on micronutrient bioavailability. This review (1) critically assesses the application of in vitro models in the exploration of mechanisms associated with iron, zinc and provitamin A carotenoid bioaccessibility and intestinal absorption from cereal foods, and (2) identifies remaining gaps in order to frame future strategies to improve the nutritional impact of cereal foods.