Losses of nutrients and anti-nutritional factors during abrasive decortication of two pearl millet cultivars (Pennisetum glaucum)

Dose-dependent Spasmolytic, Bronchodilator, and Hypotensive Activities of Panicum miliaceum L

Panicum miliaceum L. is a medicinally effective plant used in indigenous system of medicine for a variety of ailments. However, there is no comprehensive study explaining its effectiveness in gastrointestinal tract, respiratory, and cardiovascular system ailments. This study was designed to validate the pharmacological basis for the folkloric use of Panicum miliaceum L. in diarrhea, asthma, and hypertension. Panicum miliaceum extract was analyzed to detect the presence of bioactive compounds by HPLC. The isolated rabbit jejunum, trachea, and aorta were used for in vitro experiments using tissue bath assembly coupled with Power Lab data acquisition system to explore their relative effects. In-vivo experiments were performed for anti-diarrheal activity. HPLC analysis revealed the presence of gallic acid, butylated hydroxytoluene, catechin, and quercetin. Concentration dependent activities were observed by relaxing K+ (low) induced contractions having spasmolytic effect with EC50 = .358 ± .052, bronchodilator (EC50 = 2.483 ± .05793), and vasorelaxant (EC50 = .383 ± .063), probably due to the ATP dependent potassium channel activation. It was confirmed through pre-exposure of glibenclamide (specific ATP-dependent K+ channel blocker) having similarities with cromakalim. Pm.Cr revealed its antidiarrheal via in vivo experiments on rats. This study indicates that Panicum miliaceum has antidiarrheal, spasmolytic, bronchodilator, and vasorelaxant activities probably due to the ATP dependent K+ channel activation.

Monitoring bioaccessibility of iron and zinc in pearl millet grain after sequential milling

The present study was to understand the effect of sequential milling on the distribution of inhibitory factors and their relation to iron-zinc bioaccessibility in the two pearl millet cultivars differing in grain shape and size. The studies revealed that the yield of decorticated grain and bran fractions differed between the cultivars. The initial bran fractions had lower iron content, which increased on increase of decortication duration (2.33-25.14 mg/100 g), while zinc did not follow this pattern. Among the inhibitory factors, polyphenols and phytic acid were low in the initial stages of milling and subsequently increased as the milling duration increased. Microscopic studies further confirmed that iron-zinc and inhibitory factors coexist in the same tissues of the grain. The β- carotene was more concentrated in the middle layers of the pericarp. It was observed that iron bioaccessibility was the highest in the 4 min milling bran (7.7%, 3.34%) and final decorticated grain fractions (13.79%, 18.45%) of both the cultivars. Iron bioaccessibility could not be related to any particular inhibitory factors, in bran insoluble fibre and phytic acid were prominent while in decorticated grain galloyls, catechols and phytic acid were the maxima. In both the cultivars, zinc bioaccessibility was high in fractions with low phytic acid and insoluble fibre. The data presented suggest that 6 min decortication that removed around 10-15% of the bran had the highest iron and zinc bioaccessibility. The iron-rich bran fraction after appropriate processing can also be used in speciality food and thereby addresses the problem of micronutrient deficiency.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05072-x.

Improvement of nutrient bioavailability in millets: Emphasis on the application of enzymes

Millets are a traditional staple food of the dryland regions of the world and are rich in essential nutrients like protein, fatty acids, minerals, vitamins, and dietary fiber. Also, millets commonly synthesize a range of secondary metabolites to protect themselves against adverse conditions. These factors are collectively termed anti-nutritional factors and the existence of these factors in millets might reduce the accessibility of the nutrients in humans. Some of these factors include protease inhibitors, tannins, non-starch polysaccharides-glucans, phytates, and oxalates each of which might directly or indirectly affect the digestibility of nutrients. Methods like soaking, germination, autoclaving, debranning, and the addition of exogenous enzymes have been used to reduce the anti-nutritional factors and elevate the bioavailability of the nutrients. This review summarizes various methods that have been used to improve nutrient bioavailability, specifically emphasizing the use of enzymes to improve nutrient bioavailability from millets. © 2021 Society of Chemical Industry.

Effect of soaking conditions on the formation of lipid derived free radicals in soymilk

Lipid derived free radical in soymilks were studied by combining 5,5-dimethyl-pyrroline-l-oxide (DMPO) spin trap, chloroform-methanol extraction and electron spin resonance (ESR) spectroscopy. Five lipid derived free radical adducts: DMPO-X, DMPO-L, DMPO-R, DMPO-LOO, and DMPO-RO were presented in soymilks. The total amounts of spins increased as the soaking temperature increased from 4 °C to 50 °C and the soaking pH increased from 3 to 9 and in paralleled with the diffusion of soybean exudates to soaking water. Prolonged soaking of soybean at 50 °C resulted in a higher signal intensity of DMPO-R than that of DMPO-LOO. Soybean lipoxygenases (LOXs) were responsible for the formation of lipid derived free radicals in soymilks. Soybean exudates affected the total amounts of lipid radicals in linoleic acid (LA) - LOX model system. The relative signal intensities of DMPO-R and DMPO-LOO were depended on the contents of soybean exudates in the system.

Nutritional and functional roles of millets-A review

The available cultivable plant-based food resources in developing tropical countries are inadequate to supply proteins for both human and animals. Such limition of available plant food sources are due to shrinking of agricultural land, rapid urbanization, climate change, and tough competition between food and feed industries for existing food and feed crops. However, the cheapest food materials are those that are derived from plant sources which although they occur in abundance in nature, are still underutilized. At this juncture, identification, evaluation, and introduction of underexploited millet crops, including crops of tribal utility which are generally rich in protein is one of the long-term viable solutions for a sustainable supply of food and feed materials. In view of the above, the present review endeavors to highlight the nutritional and functional potential of underexploited millet crops. PRACTICAL APPLICATIONS: Millets are an important food crop at a global level with a significant economic impact on developing countries. Millets have advantageous characteristics as they are drought and pest-resistance grains. Millets are considered as high-energy yielding nourishing foods which help in addressing malnutrition. Millet-based foods are considered as potential prebiotic and probiotics with prospective health benefits. Grains of these millet species are widely consumed as a source of traditional medicines and important food to preserve health.

Bioavailable Iron and Vitamin A in Newly Formulated, Extruded Corn, Soybean, Sorghum, and Cowpea Fortified-Blended Foods in the In Vitro Digestion/Caco-2 Cell Model

BACKGROUND

Fortified-blended foods (FBFs), particularly corn-soybean blend (CSB), are food aid products distributed in developing countries. The US Agency for International Development food aid quality review recommended developing extruded FBFs with the use of alternative commodities such as sorghum.

OBJECTIVE

The objective of the study was to determine bioavailable iron and vitamin A content from newly developed extruded corn, soybean, sorghum, and cowpea FBFs compared with the nonextruded traditional food aid FBFs, corn-soy blend 13 (CSB13) and corn-soy blend plus (CSB+).

METHODS

Eleven extruded FBFs-sorghum-cowpea (n = 7), sorghum-soy (n = 3), and corn-soy (n = 1)-along with 2 nonextruded FBFs-CSB13 and CSB+, and Cerelac (Nestlé), a commercially available fortified infant food, were prepared. Bioavailable iron and vitamin A contents were assessed by using the in vitro digestion/Caco-2 cell model. Dry FBFs, aqueous fractions, and Caco-2 cell pellet vitamin A contents were analyzed by HPLC. Dry FBF and aqueous fraction iron contents were measured by atomic absorptiometry, and bioavailable iron was assessed by measuring Caco-2 ferritin contents via ELISA.

RESULTS

Iron and vitamin A concentrations in Cerelac and dry FBFs ranged from 8.0 to 31.8 mg/100 g and 0.3 to 1.67 mg/100 g, respectively. All of the extruded FBFs contained 4- to 7-fold significantly higher (P < 0.05) aqueous fraction iron concentrations compared with CSB13 and CSB+. However, there were no significant differences in Caco-2 cell ferritin and vitamin A concentrations between extruded FBFs, nonextruded FBFs, and or the basal salt solution negative control.

CONCLUSION

Results support the theory that the consumption of newly developed extruded sorghum-cowpea, sorghum-soy, and corn-soy FBFs would result in iron and vitamin A concentrations comparable to traditional nonextruded CSB13 and CSB+ FBFs.

Pearl millet minerals: effect of processing on bioaccessibility

Pearl millet is an important source of dietary energy, and provides nutritional security for people in the third world countries, particularly in Africa and Asia. Previous studies have shown that pearl millet is an excellent source of micronutrients like iron and zinc. Owing to the presence of inhibitors like phytic acid, polyphenols, and fibres, the bioaccessibility of iron and zinc is very low in pearl millet diet. The present review is an attempt to highlight the localisation of minerals, phytic acid, and polyphenols in pearl millet grains, and various strategies that are being employed for the reduction of inhibitory factors. This review also appraises and gives an overview of the application of combinations of processing conditions and enhancers, that increases the bioaccessibility of iron and zinc either by way of reduction of inhibitory factors or prevention of binding of these inhibitory factors to minerals. The above strategies could be employed to provide better insights into the relevance of different processing methods, to help in the development of speciality foods with enhanced mineral bioaccessibility.

Pearl millet processing: a review

Purpose

Pearl millet (Pennisetum glaucum) is a rich source of nutrients as compared to the major cultivated cereal crops. However, major factors which limit its utilization are the presence of anti-nutritional factors (phytate, tannins and polyphenols) which lower availability of minerals and poor keeping quality because of higher lipase activity. Therefore, this paper aims to focus on the impact of different processing methods on the nutrient composition and anti-nutritional components of pearl millet.

Design/methodology/approach

This is a literature review study from 1983 to 2017, focusing on studies related to pearl millet processing and their effectiveness in the enrichment of nutritional value through reduction of anti-nutritional compounds.

Findings

From the literature reviewed, pearl millet processing through various methods including milling, malting, fermentation, blanching and acid as well as heat treatments were found to be effective in achieving the higher mineral digestibility, retardation of off flavor, bitterness as well as rancidity problems found during storage of flour.

Originality/value

Through this review paper, possible processing methods and their impact on the nutrient and anti-nutrient profile of pearl millet are discussed after detailed studied of literature from journal articles and thesis.

Shelf life determinants and enzyme activities of pearl millet: a comparison of changes in stored flour of hybrids, CMS lines, inbreds and composites

Shelf life of pearl millet flour is very short because of rapid development of rancidity. This investigation was carried out in view of generating breeding material for development of low rancid pearl millet hybrids/varieties. Flour of twenty-one genotypes; seven hybrids, seven CMS lines, five inbreds and two composites stored in covered aluminium boxes at 37 °C for 30 days along with respective fresh flour was analysed for shelf life indicators/determinants. Crude fat content and fat acidity (FA) of fresh flour of the genotypes varied from 3.8 to 7.2% and 11 to 75 mg KOH/100 g d.m., respectively. FA in stored flour ranged between 180 and 330 mg KOH/100 g d.m. After storage, magnitude of decrease in pH of water extract of flour of the genotypes varied from 0.15 to 0.44. Activity of peroxidase (POX) varied from 378 to 588 units in control flour and irrespective of the genotypes decreased upon storage. Increase in FA (difference between FA of fresh and stored flour) rather total build up of FA was positively associated with crude fat content (r = 0.440*) indicated comparatively more prominent role of lipolytic enzymes. Chemical changes taking place in water soluble fraction of flour were independent of fat content as no correlation was discerned between fat content and decrease in pH. Among the hybrids, HHB 197 had lowest crude fat content (4.7%), lowest total build up FA (212 mg KOH/100 g d.m.), slowest increase in FA (191 mg KOH/100 g d.m.), least decrease in pH (0.31) of water soluble fraction flour during storage and lowest activity of POX in fresh flour (377 units/g d.m). Among all the tested CMS lines, inbreds and composites, HBL 11 showed pattern of quantitative changes in FA, pH and POX activity similar to the hybrid HHB 197 and was identified a promising inbred for developing low-rancid pearl millet variety or hybrid.

Effects of polyphenols and lipids from Pennisetum glaucum grains on T-cell activation: modulation of Ca(2+) and ERK1/ERK2 signaling

BACKGROUND

Pearl millet (PM), i.e., Pennisetum glaucum, is widely grown in Africa and known for its anti-oxidant and anti-hyperlipidemic properties.

METHODS

The P. glaucum grains were obtained from the region of Ouled Aïssa (South of Algeria). We assessed the effects of phenolic compounds and lipids, extracted from seeds of P. glaucum, on rat lymphocyte proliferation, activated by phorbol 12-myristate 13-acetate and ionomycin. In order to explore signaling pathway, triggered by these compounds, we assessed interleukin-2 (IL-2) mRNA expression and extracellular signal-regulated kinase-1/2 (ERK1/ERK2) phosphorylation. Finally, we determined increases in free intracellular Ca(2+) concentrations, [Ca(2+)]i, by employing Fura-2/AM in rat lymphocytes.

RESULTS

The composition of P. glaucum grains in polyphenols was estimated to be 1660 µg gallic acid equivalents (GAE)/g. Lipids represented 4.5 %, and more than 72% of the fatty acids belonged to unsaturated family. Our investigation showed that both lipid and phenolic compounds inhibited mitogen-induced T-cell proliferation. Compared with phenolic compounds, lipids exerted weaker effects on ERK-1/ERK2 phosphorylation and Ca(2+) signaling in mitogen-activated T-cells.

CONCLUSION

We conclude that the immunomodulatory effects of P. glaucum could be contributed by its phenolic and lipid contents.

Processing effects on bioactive components and functional properties of moringa leaves: development of a snack and quality evaluation

The effect of alkali pre-treatment on the nutritional, anti-nutritional and functional properties of moringa (Moringa oleifera) leaf flour (MLF), and sensory assessment of MLF-based snack product was investigated. The pre-treatment reduced the content of anti-nutrients, but improved the functional properties of MLF. The MLF-based ready-to-eat puffed snack exhibited high protein (21.6 g/100 g) and dietary fiber (14.8 g/100 g) contents while it contained a low fat content of 3.7 g/100 g. The HPLC analysis of phenolics revealed that chlorogenic and gallic acids were the predominant phenolic acids present in the raw leaf flour, whereas p-coumaric, caffeic and gallic acids were the major phenolic acids in the pre-treated leaf flour. Flavonoids such as catechin, kaempferol, rutin and luteolin were present in both MLFs and the prepared snack. Overall sensory quality indicated that the snacks had acceptable textural attributes and improved nutritional profile at the 20 % level of substitution. It is possible to develop a ready-to-eat convenience food product with good functional and nutritional properties using pre-treated moringa leaf.

Effect of processing method on physico-chemical and functional properties of two fonio (Digitaria exilis) landraces

In West Africa, landraces or local varieties of fonio are processed into many products by women using small processing units and marketed locally as well as exported to Europe and the United States. The objective of this study was to evaluate the effect of processing methods, namely parboiling, precooking and roasting on the physico-chemical and functional properties of two mainly preferred fonio landraces (Iporhouwan and Namba) by consumers. Results showed that the physico-chemical characteristics and most functional properties were significantly (P < 0.0001) affected by the processing methods. The lowest brightness (L*) values were obtained for parboiled fonio for the two landraces. However, parboiled fonio presented the best biochemical composition as compared to the dehusked, milled, precooked and roasted fonio samples. The protein contents of parboiled fonio samples were 6.06 % and 7.24 % for Iporhouwan and Namba landraces respectively. The values of peak viscosity, trough viscosity, breakdown, final viscosity and setback, were significantly higher for dehusked and milled fonio than for precooked, parboiled and roasted fonio with respect to both landraces. The milled fonio showed highest peak viscosity (2,668.5 cP) which was similar for the both tested landraces.

Iron contamination during in-field milling of millet and sorghum

Nutritionally, contaminant iron in foods may lead to overestimation of the satisfaction of iron requirement while iron deficiencies remain a widespread health problem. Iron contamination was measured in millet and sorghum grains after decortication and in-field milling using different equipments in Burkina Faso. Total iron content did not change significantly after decortication, probably due to a balance between losses resulting from the removal of iron-rich peripheral parts and contamination. Total iron contents increased significantly after mechanical milling irrespective of whether iron or corundum grindstones were used. Contamination was highly variable, ranging from 3 to 6 mg iron/100 g DM, and was mainly due to wear of the milling equipment. After in vitro digestion of traditional cereal dishes prepared with iron-contaminated or uncontaminated flours, the contaminant iron was found mainly in the insoluble fraction. Only in sorghum was a small proportion (4%) bioaccessible, showing that contaminant iron has poor nutritional interest.

Total iron absorption by young women from iron-biofortified pearl millet composite meals is double that from regular millet meals but less than that from post-harvest iron-fortified millet meals

Iron biofortification of pearl millet (Pennisetum glaucum) is a promising approach to combat iron deficiency (ID) in the millet-consuming communities of developing countries. To evaluate the potential of iron-biofortified millet to provide additional bioavailable iron compared with regular millet and post-harvest iron-fortified millet, an iron absorption study was conducted in 20 Beninese women with marginal iron status. Composite test meals consisting of millet paste based on regular-iron, iron-biofortified, or post-harvest iron-fortified pearl millet flour accompanied by a leafy vegetable sauce or an okra sauce were fed as multiple meals for 5 d. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Fractional iron absorption from test meals based on regular-iron millet (7.5%) did not differ from iron-biofortified millet meals (7.5%; P = 1.0), resulting in a higher quantity of total iron absorbed from the meals based on iron-biofortified millet (1125 vs. 527 μg; P < 0.0001). Fractional iron absorption from post-harvest iron-fortified millet meals (10.4%) was higher than from regular-iron and iron-biofortified millet meals (P < 0.05 and P < 0.01, respectively), resulting in a higher quantity of total iron absorbed from the post-harvest iron-fortified millet meals (1500 μg; P < 0.0001 and P < 0.05, respectively). Results indicate that consumption of iron-biofortified millet would double the amount of iron absorbed and, although fractional absorption of iron from biofortification is less than that from fortification, iron-biofortified millet should be highly effective in combatting ID in millet-consuming populations.

[Salinity effect on germination, growth, and grain production of some autochthonous pear millet ecotypes (Pennisetum glaucum (L.) R. Br.)]

This study compared the behaviour of six autochthonous pear millet ecotypes collected through the Tunisian territory under salt stress from germination to maturity. It showed that salt has little effect on germination rate and coleoptile emergence. However, this effect is more significant for radicular growth and between ecotypes. Salinity did not influence plant height, which seems to be a varietal characteristic, but revealed a positive effect on the foliar expansion. On the productivity level, salinity did not exert a prejudicial effect over the length of the principal candle, but improved the yield component. This adaptation to salinity is mainly due to its root system. This effect varied according to stress intensity and ecotype. Vegetative growth and yield of high-straw ecotypes was decreased by severe salinity, while ecotypes with low or medium height appear very stable on the productivity level. Such ecotypes can play an important role in the conservation and development of fragile grounds, and also be useful as a source of desirable genes for genetic improvement in salinity conditions.