Phenolic composition and antioxidant activity in seed coats of 60 Chinese black soybean (Glycine max L. Merr.) varieties

Phenolics in black soybean seed coat (BSSC) are considered to be responsible for the health benefits of black soybean. BSSCs of 60 Chinese varieties were examined for phenolic contents, anthocyanin profiles, and antioxidant activity. Total phenolic and condensed tannin contents ranged from 512.2 to 6057.9 mg gallic acid equivalents/100 g and from 137.2 to 1741.1 mg (+)-catechin equivalents/100 g, respectively. Six anthocyanins (delphinidin-3-glucoside, cyanidin-3-galactoside, cyanidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside) were detected by HPLC. Total anthocyanin contents (TAC) were from 98.8 to 2132.5 mg/100 g, and cyanidin-3-glucoside was the most abundant anthocyanin in all varieties, with a distribution of 48.8-94.1% of TAC. Antioxidant properties detected by DPPH, FRAP, and ORAC methods all showed wide variations ranging from 4.8 to 65.3 μg/100 mL (expressed as EC(50)), from 17.5 to 105.8 units/g, and from 42.5 to 1834.6 μmol Trolox equivalent/g, respectively. Sixty varieties were classified into four groups by hierarchical clustering analysis, and group 4 consisting of nine varieties had the highest phytochemicals content and antioxidant activity.     

Anthocyanin Content and Composition in Winter Blue Barley Cultivars and Lines

This study focuses on the examination of the total anthocyanin content (TAC) and spectrum of winter barley cultivars with blue caryopsis. Preparation of grain samples was simplified, and extraction was performed with 85% methanol acidified by 1% trifluoroacetic acid. Compared with our previous tests performed with 1% hydrochloric acid in aqueous methanol, the extraction process resulted in higher total anthocyanin content with more acylated derivatives. The TAC measured by spectrophotometry varied in two blue Hungarian cultivars and two lines from 46.9 to 84.4 mg/kg. The anthocyanin spectrum was analyzed by electrospray ionization tandem mass spectrometry. The predominant anthocyanins were delphinidin‐3‐malonylglucoside and cyanidin‐3‐malonylglucoside, followed by delphinidin‐3‐glucoside and cyanidin‐3‐glucoside. The caryopsis retains the anthocyanins in long‐term storage. The TAC values of the crops over the last 10 years were definable retroactively. The relative abundance of the main anthocyanin components in grains of different harvest years (2000 and 2010) was similar. Statistical analysis revealed a relatively strong negative correlation (r = –0.7439, P < 0.05) between two variables: TAC and rainfall during the grain‐ripening period.     

Phytosterol composition of nuts and seeds commonly consumed in the United States

Phytosterols were quantified in nuts and seeds commonly consumed in the United States. Total lipid extracts were subjected to acid hydrolysis and then alkaline saponfication, and free sterols were analyzed as trimethylsilyl derivatives by capillary GC-FID and GC-MS. Delta5-Avenasterol was quantified after alkaline saponification plus direct analysis of the glucoside. Sesame seed and wheat germ had the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio and sunflower kernel were richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g beta-sitosterol was found in pumpkin seed kernel, although total sterol content was high (265 mg/100 g). Phytosterol concentrations were greater than reported in existing food composition databases, probably due to the inclusion of steryl glycosides, which represent a significant portion of total sterols in nuts and seeds.     

Yield,Protein Content,and Viscosity of Starch from Wet‐Milled Corn Hybrids as Influenced by Environmentally Induced Changes in Test Weight

Forty‐three yellow dent corn samples of five different hybrids varying in test weight and moisture content were obtained from 14 different locations in 1993. The locations for acquired samples were selected randomly to cover a wide range of test weights based on preliminary data from eight states of the corn belt where 94% of the U.S. corn crop was produced in 1993. Samples were wet‐milled using a 100‐g standard laboratory‐scale wet‐milling procedure. Protein content in starch and starch viscosity were determined. Starch yield, protein content in starch, and starch viscosity were not affected significantly by test weight.     

Effect of Hybrid and Physical Properties of Individual Popcorn Kernels on Expansion Volume

The relationships between expansion volume and physical properties of three varieties of popcorn kernels were investigated on a single kernel basis. Physical properties studied were kernel size, kernel sphericity, and kernel density. Methods of measuring densities and popped volumes of individual popcorn kernels were developed. Popcorn kernels were separated into seven kernel sizes by screening with round‐hole sieves. Thirty kernels from each of three kernel sizes (4.76 < D < 5.16, 5.56 < D < 5.95, 6.35 < D < 6.75 mm) of three popcorn varieties were individually measured for sphericity, density, and popped volume. Density and sphericity measures of popcorn kernels showed little variability. Variety, kernel sphericity, and kernel density had minor effects on expansion volume. Kernel size had no effect. There were no strong linear relationships (R² = 0.28) among expansion volume and physical properties of the three varieties of popcorn kernels. The variety with the highest mean density and the highest mean sphericity showed a tendency of producing higher mean expansion volumes.     

Determining Vitreous Subclasses of Hard Red Spring Wheat Using Visible/Near‐Infrared Spectroscopy

The percentage of dark hard vitreous (DHV) kernels in hard red spring wheat is an important grading factor that is associated with protein content, kernel hardness, milling properties, and baking quality. The current visual method of determining DHV and non‐DHV (NDHV) wheat kernels is time‐consuming, tedious, and subject to large errors. The objective of this research was to classify DHV and NDHV wheat kernels, including kernels that were checked, cracked, sprouted, or bleached using visible/near‐infrared (Vis/NIR) spectroscopy. Spectra from single DHV and NDHV kernels were collected using a diode‐array NIR spectrometer. The dorsal and crease sides of the kernels were viewed. Three wavelength regions, 500–750 nm, 750–1,700 nm, and 500–1700 nm were compared. Spectra were analyzed by using partial least squares (PLS) regression. Results suggest that the major contributors to classifying DHV and NDHV kernels are light scattering, protein content, kernel hardness, starch content, and kernel color effects on the absorption spectrum. Bleached kernels were the most difficult to classify because of high lightness values. The sample set with bleached kernels yielded lower classification accuracies of 91.1–97.1% compared with 97.5–100% for the sample set without bleached kernels. More than 75% of misclassified kernels were bleached. For sample sets without bleached kernels, the classification models that included the dorsal side gave the highest classification accuracies (99.6–100%) for the testing sample set. Wavelengths in both the Vis/NIR regions or the NIR region alone yielded better classification accuracies than those in the visible region only.     

Tibetan Hull‐less Barley (Hordeum vulgare L.) as a Potential Source of Antioxidants

Tibetan hull‐less barley grows at above 4,000 m altitude. One variety grown in the plain and three varieties grown in Tibet were collected from Tianjin and Lhasa. The barleys were polished into five fractions. Total soluble phenolic content (TSPC), total antioxidant capacity (TAC), and their correlation were investigated. Phenolic compounds were analyzed by HPLC, and TSPC content was evaluated by the Folin–Ciocalteu colorimetric method. TAC was measured using 2,2‐diphenyl‐1‐picrylhydrazyl, 2,2′‐azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate), and ferric reducing ability of plasma assays. Results showed that TSPC decreased from the outer to the inner fractions, with the outermost layer containing the highest (around 2,803–7,703 μg/g) and inner endosperm the lowest (around 870–1,348 μg/g). TSPC and TAC were highly and positively correlated (r = 0.9583–0.9710). Colored hull‐less barley had higher antioxidant activity than uncolored. TSPC and TAC of Tibetan varieties in the outer layers were more than two‐fold higher than that of Tianjin hull‐less barley. Tibetan hull‐less barley bran extracts are valuable sources of bioactive components with antioxidant activity.     

Soluble and bound phenolic compounds in different Bolivian purple corn ( Zea mays L.) cultivars

In nine Bolivian purple corn ( Zea mays L.) varieties the content of phenolic compounds as well as the anthocyanin composition has been determined. The phenotypes under investigation included four red and five blue varieties (Kulli, Ayzuma, Paru, Tuimuru, Oke, Huaca Songo, Colorado, Huillcaparu, and Checchi). In purple corn, phenolic compounds were highly concentrated in cell walls. Thus, simultaneous determination of soluble and bound-form phenolics is essential for analysis, extraction, and quantification. The present study reports the determination of soluble and insoluble-bound fraction of phenolic compounds by HPLC-DAD and HPLC-ESI-MS(n) in Bolivian purple corn varieties. Enzymatic, thermal, and alkaline hydrolyses were used to obtain the cell wall-linked phenolic compounds. Ferulic acid values ranged from 132.9 to 298.4 mg/100 g, and p-coumaric acid contents varied between 251.8 and 607.5 mg/100 g dry weight (DW), respectively, and were identified as the main nonanthocyanin phenolics. The total content of phenolic compounds ranged from 311.0 to 817.6 mg gallic acid equivalents (GAE)/100 g DW, and the percentage contribution of bound to total phenolics varied from 62.1 to 86.6%. The total monomeric anthocyanin content ranged from 1.9 to 71.7 mg cyanidin-3-glucoside equivalents/100 g DW. Anthocyanin profiles are almost the same among the different samples. Differences are observed only in the relative percentage of each anthocyanin. Cyanidin-3-glucoside and its malonated derivative were detected as major anthocyanins. Several dimalonylated monoglucosides of cyanidin, peonidin, and pelargonidin were present as minor constituents.     

Anthocyanin quantification and radical scavenging capacity of Concord, Norton, and Marechal Foch grapes and wines

The anthocyanin content and the radical scavenging capacity of three non-Vitis vinifera grapes (Marechal Foch, Norton, and Concord varieties) were determined. Analyses of anthocyanins in the skin (S) and wine (W) of these grape varieties were performed by spectrophotometry, HPLC with electrochemical detection, and matrix-assisted laser desorption ionization (MALDI). The total anthocyanin contents of S samples were 258 +/- 37 mg/100 g of wet weight for Foch, 888 +/- 78 mg/100 g for Norton, and 326 +/- 5.9 mg/100 g for Concord grapes. The malvidin 3,5-diglucoside content quantified by HPLC indicated that Norton S had the highest amount of the compound (327 +/- 110 mg/100 g). The MALDI mass spectrometric analysis indicated an abundance of malvidin glucosides in W of Foch grapes and in S and W of Norton grapes and of cyanidin aglycon in S and W of Concord grapes. S samples were subjected to a radical scavenging capacity test using the 2,2-diphenyl-1-picrylhydrazyl radical and compared to Trolox. The radical scavenging capacity for Foch S was 0.78 mM Trolox equiv, that of Concord S, 0.80 Trolox equiv, and that of Norton S was highest at 0.95 Trolox equiv. The higher concentrations of malvidin 3,5-diglucoside in S of grape varieties were associated with greater radical scavenging capacity.     

Effect of Chemical Pretreatments and Lactic Acid on the Rate of Water Absorption and Starch Yield in Corn Wet-Milling

The relative effectiveness of dehulling, potassium hydroxide dipping (alkali concentrations 0.2, 0.5, and 1.0 %), and ethyl oleate spraying (aqueous emulsion 1%, v/v) to increase the rate of water absorption by dent and flint corn during steeping was compared with untreated corn samples. These pretreatments increased the water absorption rate of both hybrids when compared with the untreated control samples. To evaluate the observed increase, the diffusion coefficients of pretreated and untreated corn samples were estimated. Corn grains steeped in SO₂ aqueous solution and variable lactic acid concentrations (0.2, 0.5, and 1.0%, v/v) were performed. Absorption rates for lactic acid concentrations were ≈0.5% higher than those steeped only in SO₂ solution. This effect was more marked for dent than for flint corn. Corn samples pretreated with potassium hydroxide had lower starch yields than the control. However, the presence of lactic acid in steepwater increased the starch yield of dent and flint corn, particularly for the samples treated with alkaline solution. This procedure was particularly beneficial for flint corn. An effective release of the starch granules was achieved within 24 hr of steeping.     

Corn Kernel Structural Integrity: Analysis Using Solvent and Heat Treatments

Most corn (Zea mays, L.) processing is accomplished by causing a structural change to the kernel. Associations between corn endosperm structural components were characterized using textural analysis after solvent and heat treating kernels. Intact Asgrow 405W and B73xMo17 kernels were incubated and treated at 20, 40, 55, and 90°C for 1, 24, and 48 hr in static air, in acetone, and in aqueous solutions of water, calcium chloride, sodium chloride, sodium bisulfite, lactic acid, lime, lye, ethanol urea, and sodium dodecyl sulfate (SDS). After treatment, kernels were compressed between flat platens. Acetone did not significantly soften endosperm structure. Ethanol reduced kernel fracturability by weakening cell‐to‐cell (wall) bonds, but ethanol did not effectively reduce kernel hardness. Water and aqueous solvents swelled and softened kernels by plasticizing structural components. Bisulfite and SDS softened kernels more than water only soaks because they denatured matrix proteins. Alkaline soaks reduced fracturability and softened the kernel by dissociating both cell‐to‐cell and intracellular (starch‐protein) bonds. Soaking for longer periods and at higher temperatures increased aqueous‐based solvent softening effect. Urea imbibition into the kernel and its softening effects were highly dependent on time and temperature of soak. Endosperm structural integrity is the governed by a combination of cell‐to‐cell bonds and intra‐cellular (starch‐protein) bonds. Reagents that denatured the endosperm matrix proteins and disrupted hydrogen bonds resulted in the greatest alterations to kernel structural integrity. Ultimately a better understanding of kernel structural integrity will lead to the development of improved hybrids and process technologies designed to facilitate desirable structural changes.     

Fatty acid, triacylglycerol, phytosterol, and tocopherol variations in kernel oil of Malatya apricots from Turkey

The fatty acid, sn-2 fatty acid, triacyglycerol (TAG), tocopherol, and phytosterol compositions of kernel oils obtained from nine apricot varieties grown in the Malatya region of Turkey were determined ( P<0.05). The names of the apricot varieties were Alyanak (ALY), Cataloglu (CAT), C?loglu (COL), Hacihaliloglu (HAC), Hacikiz (HKI), Hasanbey (HSB), Kabaasi (KAB), Soganci (SOG), and Tokaloglu (TOK). The total oil contents of apricot kernels ranged from 40.23 to 53.19%. Oleic acid contributed 70.83% to the total fatty acids, followed by linoleic (21.96%), palmitic (4.92%), and stearic (1.21%) acids. The s n-2 position is mainly occupied with oleic acid (63.54%), linoleic acid (35.0%), and palmitic acid (0.96%). Eight TAG species were identified: LLL, OLL, PLL, OOL+POL, OOO+POO, and SOO (where P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl), among which mainly OOO+POO contributed to 48.64% of the total, followed by OOL+POL at 32.63% and OLL at 14.33%. Four tocopherol and six phytosterol isomers were identified and quantified; among these, gamma-tocopherol (475.11 mg/kg of oil) and beta-sitosterol (273.67 mg/100 g of oil) were predominant. Principal component analysis (PCA) was applied to the data from lipid components of apricot kernel oil in order to explore the distribution of the apricot variety according to their kernel's lipid components. PCA separated some varieties including ALY, COL, KAB, CAT, SOG, and HSB in one group and varieties TOK, HAC, and HKI in another group based on their lipid components of apricot kernel oil. So, in the present study, PCA was found to be a powerful tool for classification of the samples.     

Chemical compositions, antioxidant capacities, and antiproliferative activities of selected fruit seed flours

Seed flours from black raspberry, red raspberry, blueberry, cranberry, pinot noir grape, and chardonnay grape were examined for their total fat content, fatty acid composition, total phenolic content (TPC), total anthocyanin content (TAC), radical scavenging capacities against the peroxyl (ORAC) and stable DPPH radicals, chelating capacity against Fe(2+), and antiproliferative activities using the HT-29 colon cancer cell line. Significant levels of fat were detected in the fruit seed flours and their fatty acid profiles may differ from those of the respective seed oils. Cranberry seed flour had the highest level of alpha-linolenic acid (30.9 g/100 g fat) and the lowest ratio of n-6/n-3 fatty acids (1.2/1). The ORAC value of the chardonnay seed flour was 1076.4 Trolox equivalents mumol/g flour, and its TPC was 186.3 mg gallic acid equivalents/g flour. These values were 3-12 times higher than the other tested fruit seed flours. Furthermore, the ORAC value was significantly correlated to the TPC under the experimental conditions (P < 0.05). These fruit seed flours also differed in their TAC values and Fe(2+)-chelating capacities. In addition, black raspberry, cranberry, and chardonnay grape seed flour extracts were evaluated for their antiproliferative effects using HT-29 colon cancer cells. All three tested seed flour extracts significant inhibited HT-29 cell proliferation. The data from this study suggest the potential of developing the value-added use of these fruit seed flours as dietary sources of natural antioxidants and antiproliferative agents for optimal human health.     

Antioxidant and antiproliferative activities of raspberries

Raspberries are rich in phenolic phytochemicals. To study the health benefits of raspberries, four fresh raspberry varieties (Heritage, Kiwigold, Goldie, and Anne) were evaluated for total antioxidant and antiproliferative activities. The total amount of phenolics and flavonoids for each of the four raspberry varieties was determined. The Heritage raspberry variety had the highest total phenolic content (512.7 +/- 4.7 mg/100 g of raspberry) of the varieties measured followed by Kiwigold (451.1 +/- 4.5 mg/100 g of raspberry), Goldie (427.5 +/- 7.5 mg/100 g of raspberry), and Anne (359.2 +/- 3.4 mg/100 g of raspberry). Similarly, the Heritage raspberry variety contained the highest total flavonoids (103.4 +/- 2.0 mg/100 g of raspberry) of the varieties tested, followed by Kiwigold (87.3 +/- 1.8 mg/100 g of raspberry), Goldie (84.2 +/- 1.8 mg/100 g of raspberry), and Anne (63.5 +/- 0.7 mg/100 g of raspberry). The color of the raspberry juice correlated well to the total phenolic, flavonoid, and anthocyanin contents of the raspberry. Heritage had the highest a/b ratio and the darkest colored juice, and the Anne variety showed the lowest phytochemical content and the palest color. Heritage raspberry variety had the highest total antioxidant activity, followed by Kiwigold and Goldie, and the Anne raspberry variety had the lowest antioxidant activity of the varieties tested. The proliferation of HepG(2) human liver cancer cells was significantly inhibited in a dose-dependent manner after exposure to the raspberry extracts. The extract equivalent to 50 mg of Goldie, Heritage, and Kiwigold fruit inhibited the proliferation of those cells by 89.4 +/- 0.1, 88 +/- 0.2, and 87.6 +/- 1.0%, respectively. Anne had the lowest antiproliferative activity of the varieties measured but still exhibited a significant inhibition of 70.3+/- 1.2% with an extract equivalent to 50 mg of fruit. The antioxidant activity of the raspberry was directly related to the total amount of phenolics and flavonoids found in the raspberry (p < 0.01). No relationship was found between antiproliferative activity and the total amount of phenolics/flavonoids found in the same raspberry (p > 0.05).     

Micropycnometer Measurement of Single-Kernel Density of Healthy,Sprouted, and Scab-Damaged Wheats

Samples from four market lots of hard red winter and soft red winter wheat containing sprout- and scab-damaged kernels were used to test a prototype single-kernel density micropycnometer. Fifteen kernels for each damage type and an equal number of healthy kernels were weighed to the nearest 0.01 mg, then measured for volume to the nearest 1.0 μL. Volume measurements for all kernels were performed three consecutive times with the micropycnometer, then kernels were evaluated for weight, size, moisture, and hardness using a Single Kernel Characterization System. The structure of the sampling plan and the goals of the study indicated that a mixed-model statistical analysis was needed. The fixed effects were wheat class and type of kernel, and the random effects included lot, the interaction of lot with class and kernel type, kernels within each lot, and repeated measures of single-kernel density. Results indicated that variability of the three measurements per kernel did not depend on type of kernel or class of wheat. The standard deviation for repeated density measurements was 0.0029 g/cm³. Kernel-to-kernel variability changed depending on the type of kernel; healthy and sprout-damaged kernels showed similar variability in density, whereas scab damaged kernels had a variance about four to five times higher. Type of kernel significantly affected mean density; healthy kernels averaged 1.28 g/cm³, sprout-damaged kernels averaged 1.19 g/cm³, and scab-damaged kernels averaged 1.08 g/cm³. Wheat class did not exert a significant influence on singlekernel density. Attempts to predict single-kernel density using kernel weight, size, moisture, and hardness found no relationships of practical importance.     

Use of Pigmented Maize in Both Conventional Dry‐Grind and Modified Processes Using Granular Starch Hydrolyzing Enzyme

In the dry‐grind ethanol process, distillers dried grains with solubles (DDGS) is the main coproduct, which is primarily used as an ingredient in ruminant animal diets. Increasing the value of DDGS will improve the profitability of the dry‐grind ethanol process. One way to increase DDGS value is to use pigmented maize as the feedstock for ethanol production. Pigmented maize is rich in anthocyanin content, and the anthocyanin imparts red, blue, and purple color to the grain. It is reported that anthocyanin would be absorbed by yeast cell walls during the fermentation process. The effects of anthocyanin on fermentation characteristics in the dry‐grind process are not known. In this study, the effects of anthocyanin in conventional (conventional starch hydrolyzing enzymes) and modified (granular starch hydrolyzing enzymes [GSHE]) dry‐grind processes were evaluated. The modified process using GSHE replaced high‐temperature liquefaction. The ethanol conversion efficiencies of pigmented maize were comparable to that of yellow dent corn in both conventional (78.4 ± 0.5% for blue maize, 74.3 ± 0.4% for red maize, 81.2 ± 1.0% for purple maize, and 75.1 ± 0.2% for yellow dent corn) and modified dry‐grind processes using GSHE (83.8 ± 0.8% for blue maize, 81.1 ± 0.3% for red maize, 93.5 ± 0.8% for purple maize, and 85.6 ± 0.1% for yellow dent corn). Total anthocyanin content in DDGS from the modified process was 1.4, 1.9, and 2.4 times of that from the conventional process for purple, red, and blue maize samples, respectively. These results indicated that pigmented maize rich in anthocyanin did not negatively affect the fermentation characteristics of the dry‐grind process and that there was a potential to use pigmented maize in the dry‐grind process, especially when using GSHE.     

Selecting and Sorting Waxy Wheat Kernels Using Near‐Infrared Spectroscopy

An automated single kernel near‐infrared (NIR) sorting system was used to separate single wheat (Triticum aestivum L.) kernels with amylose‐free (waxy) starch from reduced‐amylose (partial waxy) or wild‐type wheat kernels. Waxy kernels of hexaploid wheat are null for the granule‐bound starch synthase alleles at all three Wx gene loci; partial waxy kernels have at least one null and one functional allele. Wild‐type kernels have three functional alleles. Our results demonstrate that automated single kernel NIR technology can be used to select waxy kernels from segregating breeding lines or to purify advanced breeding lines for the low‐amylose kernel trait. Calibrations based on either amylose content or the waxy trait performed similarly. Also, a calibration developed using the amylose content of waxy, partial waxy, and wild‐type durum (T. turgidum L. var durum) wheat enabled adequate sorting for hard red winter and hard red spring wheat with no modifications. Regression coefficients indicated that absorption by starch in the NIR region contributed to the classification models. Single kernel NIR technology offers significant benefits to breeding programs that are developing wheat with amylose‐free starches.     

Uncommonly high levels of 3-deoxyanthocyanidins and antioxidant capacity in the leaf sheaths of dye sorghum

Extracts from leaf sheaths of farmers' varieties of dye sorghum cultivated and used in Benin as a source of biocolorings were analyzed for their anthocyanidin and phenolic contents, as well as their antioxidant capacity. The aim was to identify and quantify the types of anthocyanin and phenolic acids. The total anthocyanin content of the leaf sheaths ranged from 13.7 to 35.5 mg of cyanidin 3-glucoside equivalent/g of dry matter (DM), with an average of 27.0 mg/g. The total anthocyanin content is 90 times higher than levels usually reported in fruits and vegetables. Anthocyanin consisted essentially of apigeninidin and luteolinidin, two 3-deoxyanthocyanidins with many applications in food, beverage, and pharmaceutical industries. The apigeninidin content of the leaf sheaths was 30 times higher than that in cereal bran and ranged from 14.7 to 45.8 mg/g, with an average of 31.3 mg/g. The amount of luteolinidin ranged from 0.4 to 2.4 mg/g, with a mean of 1.2 mg/g. The total phenolic content expressed as gallic acid equivalent averaged 95.5 mg/g. The free phenolic acids identified were benzoic acid, p-coumaric acid, and o-coumaric acid at amounts of 801.4, 681.6, and 67.9 μg/g, respectively. The leaf sheaths of dye sorghum have an antioxidant capacity [3.8-5.6 mmol of Trolox equivalent (TE)/g of DM] much higher than that reported for cereal bran and fruits and vegetables.     

Factors Affecting the Alkaline Cooking Performance of Selected Corn and Sorghum Hybrids

Dent corn (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) sample sets representative of commonly grown hybrids and diverse physical attributes were analyzed for alkaline cooking performance. The influence of kernel characteristics including hardness, density, starch properties (thermal, pasting, and crystallinity), starch content, protein content, and prolamin content on alkaline cooking performance was also determined. Corn nixtamal moisture content was lower for hard, dense kernels with high protein contents; sorghum nixtamal moisture content was lower for kernels with low moisture contents and low starch relative crystallinities. Statistically significant (P < 0.05) regression equations showed that corn nixtamal moisture content was influenced by TADD (tangential abrasive dehulling device) index, kernel moisture content, starch content, and protein content; sorghum nixtamal moisture content was influenced by starch relative crystallinity, kernel moisture content, and abrasive hardness index. Pericarp removal was not strongly correlated with kernel characterization tests. Location (environmental) and hybrid (genetic) factors influenced most kernel characteristics and nixtamalization processing variables.     

Relationships Between the Microstructure,Physical Features,and Chemical Composition of Different Maize Accessions from Latin America

Chemical composition (moisture, total lipids, protein, and apparent amylose) and some physical features (1,000 kernel weight, hardness, and anatomical composition) were determined in 71 accessions representing races of maize from Latin America. Their microstructural characteristics (size and compaction of endosperm cell bodies, pericarp thickness, horny‐floury endosperm ratio, and morphology and size of starch granules) were also evaluated using environmental scanning electron microscopy (ESEM). Compaction was the most important microstructural feature of the maize kernels, representing kernel hardness. Highly compact kernels tended to be hard, with high protein, pericarp, and hard‐endosperm content and high pericarp thickness, but with low moisture, amylose content, and kernel weight and size. The opposite was observed in the least compact kernels. Highly compact kernels tended to have small, polygonal starch granules (<10 μm), while the least compact kernels contained large, spherical granules (>10 μm). These results suggest that microstructure is responsible for the physical features of maize kernels and that microstructure is related to chemical composition.