White Dent Research Articles

Mogućnosti primene hibrida kukuruza u proizvodnji baby corn konzervisane hrane

Five maize hybrids were used in this research: two yellow and one white dent, sweet hybrid, and yellow popcorn. Five brine recipes with acetic acid were examined, of which two with the addition of potassium sorbate. The brines with preservatives were stable for 16 months without colour changes of the liquid and corn cobs. The pH of brines ranged from 3.39 to 3.89. Canned hybrids ZP 366 and ZP 611k in brine without sugar, and with the addition of potassium sorbate and potassium metabisulfite marked as Number 5, showed the best sensory characteristics. The protein content determined in ZP 366 (9.56 %) and ZP 611k (10.23 %) did not vary significantly compared to whole-grain maize flour, while crude fibre content (7.67 and 6.88 %), and ash content (21.96 and 20.72 %) were significantly higher than in flour (crude fibre: 2.40; 2.64 %, ash:1.35; 1.48 %, respectively). This research will be continued in order to implement preliminary findings and new data on this subject.

Membrane Performance of Micro and Ultrafiltration on Folic Acid Separation from Dent Corn (Zea mays var. indentata) Hydrolyzed by Rhizopus oligosporus-C1

Performance of microfiltration (MF) and ultrafiltration (UF) membranes to separate of folic acid from corn (Zea mays var. indentata) hydrolysate equipped in stirred filtration cell (SFC) mode were performed as a reference guide toward semi pilot scale. Separation on hydrolysate suspension of yellow dent corn (HSYCD) and hydrolysate suspension of white dent corn (HSWCD) as a results of hydrolysis of protease enzyme of Rhizopus oligosporus strain-C1 0.025 % and 0.075 % (w/w, dissolved protein) at pH 5 and 30 °C for 24 hours was conducted by MF (0.45 µm) and UF (100000 MWCO) membranes at stirrer rotation speed 400 rpm and trans-membrane pressure (TMP) of 20, 30 and 40 psia for 30 minutes. The experimental result showed that based on optimization of fluxes, the best performances of MF and UF membranes on HSYDC and HSWDC were achieved at TMP 40 psia and gave fluxes of 0.0534 and 0.0508 mL/cm2.min., respectively. In these process conditions, it take place an increase of folic acid in concentrates of HSYDC and HSWDC compared with before process (feed). Identification of molecular weight (MW) on folic acid from HSYDC and HSWDC displayed dominant folic acid monomer at T2.7, and T2.4 and T2.89. This matter showed that commodity of yellow dent corn has more potential use as source of folic acid compared with white dent corn at both similar condition of hydrolysis and separation and/or purification processes.

Genetic Structure, Core Collection, and Regeneration Quality in White Dent Corn Landraces

Genetic diversity and structure of plant germplasm collections, frequently determined by molecular markers, can be used to assist breeding programs, to validate core collections determined by other methodologies, to identify priority accessions for conservation, and to confirm genetic integrity after regeneration. This research aimed to study the genetic diversity and structure of the Uruguayan white dent maize collection, to evaluate the genetic representativeness of its core collection (previously defined by phenotypic traits), and to confirm the genetic integrity of seven regenerations made in Mexico and Uruguay in comparison with the original accessions. Ninety accessions were fingerprinted using 26 simple sequence repeat (SSR) markers. Genetic structure was analyzed by Ward clustering, canonical analysis, and a Bayesian approach based on allelic frequencies. All SSR markers were polymorphic with a mean number of alleles (A) of 7.43, an effective allele number (Ae) of 3.04, and expected heterozygosity of 0.579. The genetic variation between accessions was 0.251, and variation within accessions was 0.749. Four genetic groups were obtained using the three approaches. The core collection represented the structure of the whole collection because the four genetic groups were proportionally represented. The genetic diversity in the core collection did not differ from the entire collection in A, Ae, expected heterozygosity (He) percentage of polymorphic loci (%P), and expected heterozygosity within accessions (Hs). Most regenerations (9 out of 14) preserved the genetic integrity of original accessions, whereas in other cases, either new or lost alleles caused genetic differences. The analysis of genetic structure and diversity of germplasm collections, in combination with morphological characterizations, helps to define ex situ conservation strategies and usage in breeding programs.

Modification process in nixtamalization of folic acid-rich dent corn (Zea mays identata) and its identification as smart food fortificant

A modification on nixtamalization process of dent corn (Zea mays identata) was conducted in order to recover natural folic acid-rich corn. Nixtamalization process on varieties of white dent corn and yellow dent corn subsequently were performed by steeping solution of Ca(OH)2 at concentrations of 0, 10, 20 and 30 % (w/w corn dissolved protein) for 18 hours, and boiling at 90 °C for 15, 30, 45 and 60 minutes. Result of research showed that concentration of Ca(OH)2 solution becoming more and more high and long boiling time increased both folic acid and reducing sugar, dropped total solids and total sugar, and fluctuated dissolved protein for both types of corn. Nixtamalization optimalization of white dent corn and yellow dent corn were achieved at combination of Ca(OH)2 20 % (w/w corn dissolved protein) for 60 minutes of boiling and Ca(OH)2 30 % for 30 minutes of boiling and gave folic acid of 466.81 and 506.74 μg/mL, respectively. In this condition, it is occurred an increase of folic acid 192.3 % (1.9 folds) and 139.89 % (1.4 folds) when compared to initial material of corn. Identification on folic acid monomer and glutamic acid monomer of both nixtamalized dent corn and yellow dent corn at optimum operation condition displayed domination of folic acid monomer with molecular weight (MW) 442.56 Dalton (Da.) with relative intensity 25.51 %, and 441.73 Da. with relative intensity 100 %, while glutamic acid monomer of nixtamalized yellow dent corn and nixtamalized white dent corn were dominated by monomer with MWs of 148.27 Da. and 148.32 Da., and relative intensity 3.73 and 1.8 %.

Periodic Physical Disturbance: An Alternative Method for Controlling Sitophilus zeamais (Maize Weevil) Infestation.

Sitophilus zeamais Motschulsky is the most important insect pest of stored maize in tropical regions. The objective of this study was to determine the practicality of periodic physical disturbance on S. zeamais mortality and its adoption by smallholder farmers in developing countries. In this experiment, treatments and control were arranged in a randomized block design with three replications and three storage times in three regions of Tanzania. Region was used as the blocking variable. A total of 108 clean 20-L plastic containers were each loaded with 10 kg of fresh white dent corn and 0.50 kg of maize infested with S. zeamais. For the treatment, containers were disturbed twice a day, whereas for the controls the containers were not disturbed until the end of storage. The overall mortality rate (%) after 30, 60, and 90 days of storage were 88%, 96%, and 98%, respectively. A statistically significant difference (p < 0.05) was observed for the number of live S. zeamais between the control and experimental treatments. Additionally, the number of live S. zeamais in the treatment significantly decreased as storage time increased. This study shows the potential of a feasible, simple, affordable, and effective method of protecting maize grain for small-holder farmers in developing countries without using chemicals.

Evaluation of maize weevils Sitophilus zeamais Motschulsky infestation on seven varieties of maize

Sitophilus zeamais (Motschulsky), the maize weevil, is a serious pest of economic importance in stored products in tropical and subtropical countries; infestation often starts in the field, but serious damage is done during maize storage. This study evaluated S. zeamais infestation on seven varieties of maize. Seven commercial maize varieties (white dent, yellow dent, orange flint, Indian flint, white popcorn, yellow popcorn and sweet corn), two temperature conditions (10 and 27 °C) and three storage times (30, 60, and 90 d) were used. The moisture contents of all maize samples were adjusted to 15.5 ± 0.5% (wet basis) prior to initiating storage trials. Numbers of live weevils, – seed damage, weight loss, and weight of powder produced were assessed at the end of each storage time. As expected, severe damage was observed at 27 °C and 90 d for all maize varieties. Exponential growth rates of S. zeamais were observed in almost all maize varieties. Among seven varieties evaluated, orange flint corn, yellow and white popcorn show resistance to S. zeamais. Nevertheless, sweet and dent corn were most susceptible to S. zeamais -infestation - Higher numbers of live S. zeamais were observed on Indian flint corn, sweet corn and yellow dent corn. Consequently, there was higher seed weight damaged and weight loss. Further, seed damaged, percentage seed weight loss and weight of powder produced was significantly and positive correlated with number of live S. zeamais (r = 0.91, P < 0.05), (r = 0.88, P < 0.05), and (r = 0.89, P < 0.05) respectively. Thus, some varieties of flint corn and popcorn can be considered as potential maize varieties to be used to reduce postharvest loss of maize in tropical countries due to natural resistance to S. zeamais infestation.

PHYSICAL AND MECHANICAL CHARACTERISTICS OF CORN KERNELS

The present study aimed to determine and recognize the physical ans mechanical properties as an important role in designing and developing of specific machines and their operations such as planting, harvesting and grading, Physical characteristics of corn kernels were obtained of two varieties: White Dent Corn single hybrid 10 (Corn 10), and yellow Dent Corn single hybrid 162,(Corn 162).For each of the physical characteristics, corn 10 gave the highest values comparing with corn 162. For each of the material surfaces, the galvanized surface gave the lowest static coefficient of friction (0.531 , 0.459)for corn 10 , corn 162 respectively; and for the same group, the plywood surface gave the highest value (0.624 , 0.586) for the two varieties respectively. For the painted surfaces, the oven - baked enamel processed paint gave the lowest values (0.48, 0.5) for the two varieties comparing with Polish paint, Mutt paint, and untreated mild - steel surfaces which gave (0.828, 0.72 – 0.72, 0.71 – 0.572, 0.549) respectively.

Fermentation of Aflatoxin Contaminated White Dent Maize (Zea mays)

Fermentation of Aflatoxin Contaminated White Dent Maize (Zea mays)

MECHANICAL PROPERTIES OF CORN KERNELS

Mechanical Properties of fresh corn kernels were obtained for the two varieties, White Dent Corn Single Hybrid 10 and Yellow Dent Corn Single Hybrid 155 at different levels of moisture contents ranged from 30.26 to 9.88 (w.b.%). The kernels mechanical properties were obtained firstly related to single kernels included modulus of elasticity, maximum compressive stress, rupture energy, rigidity force, penetration force and moisture content. Secondly the mechanical properties of corn kernels in bulk were measured and included pressure-density relationships and stress strain behavior. Data were demonstrated in tables, graphically and regression equations were developed to describe the previous mechanical properties dependence on moisture contents for each variety.

Indentation Measurements on Compacted Pharmaceutical Powders: Establishing the Sources of Variation in White Light Interferometer Dent Measurements

Abstract Indentation measurements are commonly used to determine the mechanical properties of pharmaceutical compacts. Specifically, they are used to assess their resistance to plastic deformation and to help predict tablet properties. To date there has been little research reported aimed at understanding the variation associated with these types of measurements. In this work experiments were conducted to identify and, where possible, quantify the sources of variation for dent measurements on pharmaceutical excipient compacts using a white light interferometer. Statistical analyses of the results revealed that operator-to-operator and sample-to-sample variability each accounted for approximately 2.5 % of the total variability, whereas the intrinsic error of the experimental test procedure was about 10 % of the total variability. The remaining variability was due to known differences in the material properties or test conditions. The capability of the dent dimension measurements was determined to be approximately 8 % of the mean value, and thus it was possible to quantify the discriminating power of this type of compact mechanical property measurement.

Genetic Diversity of Two Important Groups of Maize Landraces with Same Name in China Revealed by M13 Tailed-Primer SSRs

Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank (CNG). The present study investigated the genetic diversity of these two important groups of maize landraces, as well as the relationships within and among them. Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13. Summary statistics including average number of alleles per locus, gene diversity/expected heterozygosity, and observed heterozygosity were carried out using PowerMarker ver. 3.25 software. The test of Hardy-Weinberg equilibrium (HWE) and linkage disequilibrium (LD) of all the 44 maize landrace accessions were also performed by PowerMarker. We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen (6.44 alleles per locus in White Dent, 4.48 in Golden Queen), while both groups of maize landraces had a relatively high but similar gene diversity (0.61 of White Dent, 0.63 of Golden Queen). The fixation index (F ST) was only 0.0044, while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%, respectively. The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base. The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high, indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces. Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE, whereas Golden Queen was under HWE.

Corn Borer (Lepidoptera: Noctuidae and Crambidae) Resistance of Main Races of Maize from North America

Resistance to corn borers, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) and Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) in maize, Zea mays L., populations is partial, and more resistant populations are needed. The objective of this research was to compare resistance to corn borers of the main maize races from North America. Twenty open-pollinated maize populations belonging to the races Southern Dent, Corn Belt Dent, and Northern Flint, and three check populations, were evaluated under artificial infestation with S. nonagrioides and O. nubilalis. None of the populations had complete resistance. Northern Flint had the lowest yield under corn borer infestation, whereas Southern Dent had the highest yield but also the largest damage. Corn Belt Dent had a shorter growing cycle and similar yield of infected plants than Southern Dent. The checks had intermediate yield and resistance and were not significantly different from Corn Belt Dent for any trait. The Southern Dent populations Tennessee Red Cob and White Dent (PI221885 and PI311232) could be used as sources of tolerance to corn borers, although they are not expected to provide great gains compared with the levels of tolerance already present in some Corn Belt Dent and European Flint populations and would require adaptation to short growing cycle. The Corn Belt Dent synthetic BS17 had the highest yield and general agronomic performance under corn borer infestation, along with Rustler and Silver King, and the European Flint composite EPS13.

Selective Nixtamalization of Fractions of Maize Grain (Zea mays L.) and Their Use in the Preparation of Instant Tortilla Flours Analyzed Using Response Surface Methodology

ABSTRACTUsing a continuous decorticating machine, white dent corn was efficiently separated, after brief steeping in water, into two fractions: the first (12.5%) consisting mainly of pericarp, germ, and tip cap (PGT); the second (87.5%) consisting of endosperm. Nixtamalization of the maize fractions in the presence of 0.6% (w/w) lime caused an increase in the hot‐paste viscosity at 90°C, while nixtamalization of PGT at lime inputs &lt;0.6% (w/w) resulted in decreased viscosity. Three domains were found for the viscosity of nixtamalized endosperm at 90°C: lower concentrations of lime (&lt; 0.15%, w/w) resulted in lower viscosity values; increased lime (0.15% – &lt;0.3%, w/w) increased the viscosity values; and a lime concentration of 0.3% (w/w) resulted in a lower viscosity value. The response variables (water absorption index, water solubility index, initial viscosity, and viscosity at 90°C for nixtamalized PGT, and compression force and compression area of tortillas) indicated that the mathematical models fit the experimental data and the variance of the models was highly significant. Tortillas of good functional characteristics similar to tortillas produced by the traditional process were obtained when 5% nixtamalized fractions of PGT were blended with 95% nixtamalized endosperm.

Nutrient Composition and Weight Evaluation of some Newly Developed Maize Varieties in Nigeria.

The weight and chemical composition of improved white and improved yellow dent maize was compared with some local floury maize varieties. The average protein content was 10.8%, 11.1% and 10.5% in improved white dent, improved yellow dent and local floury respectively. The major carbohydrate in all the varieties was starch with local floury having a slightly higher level of sugar. Improved yellow dent was significantly (P 0.05) change in the average weight of all varieties. The average weight ranged between 28.2 in improved white dent to 29.8 in improved yellow dent. The yellow dent variety will be particularly useful in improving level of micronutrient intake. The Journal of Food Technology in Africa Volume 7 No.1, 2002, pp. 27-29 KEY WORDS: Nutrient composition, white dent, yellow dent, local floury maize varieties.

Analysis of Genetic Variability in Long-term Callus Cultures and Regenerated Plants of Maize.

Zea mays ssp. mays cv. Colorado Klein organogenic calli were initiated from 11 daysold embryos on basic medium containing 2.25 μM 2, 4-D. The callus originated from one of the embryos was subcultured every month to fresh medium supplemented with 4.5 or 9 μM 2, 4-D, for 84months. The first chromosomal abnormalities appeared after 17 months of culture : 70% of regenerated plants were normal, 20% aneuploid and the remaining 10% were tetraploid. Thereafter chromosomal aberrations increased. Most (95%) of the plants regenerated after 32 months had one extra chromosome, and meiotic analysis of regenerants showed deficiencies, duplications, inversions, translocations and ring chromosomes. Chromosome number of cells from 60 months old callus ranged from 2n=18 to 2n=23, but 90% of regenerated plants had 2n=21 and the remaining 10% had 2n=20. Plants regenerated from 64 to 84 months old callus were sterile. Also, phenotypic alterations were observed in plants regenerated from 32 months and older calli. Although original maize plants are yellow flint, 75% of R0 ears showed white flint kernels and their progeny exhibited yellow flint, white flint, white dent and white sugary caryopses.

Occurrence of Fusarium and fumonisins on food grains and in foods.

Fusarium moniliforme Sheldon occurs worldwide on corn intended for human and animal consumption. A closely related species Fusarium proliferatum also occurs frequently on corn. Yellow dent corn, white dent corn, white and yellow popcorn and sweet corn may be contaminated. Both organisms are capable of producing fumonisins, including Fumonisin B1 (FB1), Fumonisin B2 (FB2) and Fumonisin B3 (FB3). Fumonisins have been found in corn and corn based foods worldwide. Fumonisins may be found in sound whole kernel corn at levels at or below 1.0 microgram/g. By contrast animal disease problems begin to occur at fumonisin levels above 5.0 to 10.0 micrograms/g. Corn based food products that have the most frequent and highest fumonisin levels, besides whole kernel corn, are corn meal, corn flour and corn grits. In the U.S., corn meal and flour have been found contaminated with FB1 at levels from 0.5 to 2.05 micrograms/g, and grits from 0.14 to 0.27 microgram/g. Corn flakes, corn pops, corn chips and tortilla chips have typically been found negative when tested for fumonisins. Popcorn, sweet corn and hominy corn have been found contaminated with sporadic, low levels (0.01 to 0.08 microgram/g) of fumonisins. Contamination levels of corn based foods in Europe appear to be similar to slightly lower than similar products in the U.S., with the possible exception of Italy, where their corn hybrids and corn-based foods appear to be more frequently contaminated with higher levels of fumonisins.

Incidence and Levels of Fusarium moniliforme, Fusarium proliferatum and Fumonisins in Corn and Corn-Based Foods and Feeds1

Fusarium moniliforme Sheldon occurs worldwide on corn intended for human and animal consumption. A closely related species Fusarium proliferatum also occurs frequently on corn. Yellow dent corn, white dent corn, white and yellow popcorn and sweetcorn may be contaminated. Both organisms are capable of producing a group of toxins known as fumonisins, of which Fumonisin B1 (FB1), Fumonisin B2 (FB2) and Fumonisin B3 (FB3) are most common. Fumonisins have been found in corn and corn-based foods worldwide. Fumonisins may be found in sound whole kernel corn at levels at or below 1.0 μg/g. By contrast animal disease problems begin to occur at fumonisin levels above 5.0 to 10.0 μg/g. Corn-based food products that have the most frequent and highest fumonisin levels, besides whole kernels, are corn meal and corn grits. In the United States, corn meal has been found contaminated with Fumonisin B1 at levels from 0.5 to 2.05 μg/g, and grits from 0.14 to 0.27 μg/g. Corn flakes, corn pops, corn chips and tortilla chips have been found negative for fumonisins. Popcorn, sweetcorn and hominy corn have been found contaminated with sporadic, low levels (0.01 to 0.08 μg/g) of fumonisins. The effects of processing on fumonisins in corn are still largely unknown. Heating may cause a loss of fumonisins in corn, but it may be a loss of detectability rather than degradation.

Aflatoxin Destruction in Corn Using Sodium Bisulfite, Sodium Hydroxide and Aqueous Ammonia

Naturally contaminated yellow dent corn containing 235 ppb of aflatoxin B1 and B2 was adjusted to a moisture content of 20% and then treated for 24 h at ambient temperature with NaHS03, NaOH or aqueous NH3 at 0.5%, 1.0%, or 2.0% concentrations. All treatments were effective in reducing aflatoxin B1 and B2 levels. Sodium bisulfite was more effective in destroying aflatoxins than were NaOH or aqueous NH3 at 0.5% and 1.0% concentrations, while NaOH and aqueous NH3 were more effective than bisulfite at 2.0% concentration. Subjecting yellow corn samples to either NaHSO3, NaOH or aqueous NH3 at 2.0% concentrations reduced aflatoxin B1 and B2 levels to below the FDA guideline of 20 ppb total aflatoxin. Sodium bisulfite was also effective in reducing the levels of aflatoxins in a white dent corn sample containing 81 ppb of aflatoxin B1 and 12 ppb of aflatoxin B2. Results suggest that NaHSO3, NaOH or aqueous NH3 can be used to effectively destroy aflatoxins in corn and possibly other agricultural commodities.

Selective Fertilization in Maize, Zea mays L. : II. An Attempt for Generalization of Advantage of Pollen Grains from F1 Plant

Previously the authors (MURAKAMI et al. 1972) reported the predominance of pollen grains from F1 plant in selective fertilization as compared wlth pollen grains from inbred lines. The selective fertilization of pollen graln.s from inbred lines and F1s observed in that experiment was, however, tested by using one particular inbred line as a female parent to be pollinated and as a pollen source to be mixed with pollen grains from other lines. The present study was planned to confirm whether the predominance of pollen grains from F1 plant in selective fertilization reported in the previous paper generally occurs in the pollination of all combinations of pollen and female parents including F1. In thls experiment (Table 1), two sets of inbred lines and their F1s were used as female parents, i.e. A34 (W1)', CI 64 (W2), and A34XCI 64 (WF1) in Set I, and Koshu-564 (O1)' Outomorokoshi-143 (02), and Koshu-564XOutomorokoshi-143 (OF1) in Set II As regards endosperm character, the materials for female parents in Set I were white dent, and on the other hand those of in Set II were orange flint, respectively. Due to xenia, the kernels fertilized by pollen grains from the alternative endosperm characters in pollen-mixture always produced yellow kernel in the both sets. The pollination by pollenmixture consisting of equal volumes of pollen grains from an inbred line or F1 plant of two different endosperm characters was performed (Table 2).

Studies on Dry Matter Production in Corn Plant : III. Changes and interactions of plant factors constituting canopy photosynthesis according with the development of growth stages

Five varieties of corn seeds (Golden Cross Bantam, Kohshu Tomorokoshi, Koh No.3, White Dent Corn and Chokoh No.161) were sown under three different levels of spacing (30cm × 30cm, 45cm × 45cm, 60cm × 60cm) to know the changes and interaction of plant factors constituting canopy photosynthesis. Results obtained are as follows. 1. Within the limit of this experiment, leaf amount regulated the dry matter production of corn. Therefore, high correlation between LAI and CGR was observed at any growth stages. 2. However, if limited the range of LAI in addition to devide growth stage into three (early vegetative stage, active vegetative stage and ripening stage), contribution rate of other plant factors against CGR became clear. That is, during the stages having only poor amount of leaf area, the larger the value of light extinction coefficient K', the higher the CGR obtained. But after leaf amount was plentifully attained, vice versa. 3. Deviding the growth stage and LAI in the same way as 2, positive correlation between NAR and CGR were observed at any growth stages