Prediction of total phenols,condensed tannins,and 3-deoxyanthocyanidins in sorghum grain using near-infrared (NIR) spectroscopy

The reported high phenolic levels in sorghum have led an interest from sorghum breeding programs in developing and identifying germplasms with high phenolic levels, which require screening a large number of samples to find those with the highest levels. Since wet chemistry screening methods are slow, expensive, and destructive, the use of NIR calibration curves could be an alternative. The objectives of this project were to determine the variation range in total phenols, condensed tannins, and 3-deoxyanthocyanidin levels in a diverse set of sorghum genotypes and to assess the predictive value of NIR curves to estimate these compounds in sorghum. A calibration curve to estimate each compound was developed and validated with an independent validation set. Calibration curve correlations for total phenols, condensed tannins, and 3-deoxyanthocyanidins were r = 0.98, 0.97, and 0.99, respectively. Correlations between NIR-predicted values and reference values in the validation set were significant for total phenols (r = 0.93), condensed tannins (r = 0.81) and 3-deoxyanthocyanidin (r = 0.82). These indicated that sufficient variation for these compounds existed within sorghum and that NIR calibration curves could be used to rapidly and non-destructively predict total phenols, condensed tannins, and 3-deoxyanthocyanidins concentrations in whole grain sorghum.     

Evaluation of phenolics and antioxidant activity of black sorghum hybrids

Black sorghums possess very high levels of the rare 3-deoxyanthocyanidins which can be used as natural food colorants with health benefits. However, these sorghum genotypes have undesirable agronomic properties (i.e. high height, low yield, increased weathering). Black sorghum hybrids with improved agronomic properties were developed and their phenolic profiles and antioxidant activity were compared with black sorghum lines. Black sorghum hybrids were significantly lighter in colour than the lines (P < 0.001). All hybrids had a pigmented testa which was indicated by the presence of condensed tannins, which significantly increased total phenol levels and antioxidant activity. The 3-deoxyanthocyanidin, flavan-4-ol, and flavone levels were significantly lower in the hybrids (P < 0.001) and were strongly correlated to pericarp colour (P < 0.001). Flavanone levels were not significantly different among the lines and hybrids (P > 0.05) and pericarp colour did not affect their levels (P > 0.05). Even though the 3-deoxyanthocyanidin levels were lower in black sorghum hybrids than in the lines, the presence of condensed tannins in the hybrids significantly increased their antioxidant activity. Since 3-deoxyanthocanidin levels were dependent on pericarp colour, hybrids with increased blackness intensity should be developed to increase the stable 3-deoxyanthocyanidins.     

Phenolic compounds profile in sorghum processed by extrusion cooking and dry heat in a conventional oven

Sorghum (Sorghum bicolor L.) is a gluten-free cereal that has the highest content of phenolic compounds among cereals. It needs to be processed prior to use for human consumption, which may change its antioxidant profile. The knowledge on the effects of extrusion and dry heat in a conventional oven on flavones, flavanones, and proanthocyanidins is limited. Thus, the content and stability to dry heat in a conventional oven (DHCO) and extrusion cooking on phenolic compounds profile in sorghum genotypes were evaluated. Flavanones and flavones decreased after extrusion cooking (100%) and DHCO (31.7–61.6%). The 3-deoxyanthocyanidins were stable in DHCO but were susceptible to extrusion cooking (70.7–93.9%). Proanthocyanidins were identified only in the genotype SC391 and were reduced after both treatments (DHCO: 39.2% and extrusion cooking: 52.1%). Phenols decreased in the genotype SC319 submitted to DHCO (8.3%) and in all extruded genotypes (13.6–14.9%). The DHCO increased the antioxidant capacity in all genotypes, whereas extrusion cooking reduced antioxidant capacity in only two genotypes. In general, differential stability of the major flavonoids in sorghum was observed under DHCO and extrusion cooking, implying that different processing techniques can be selected to minimize losses of bioactive polyphenols in sorghum depending on the flavonoid composition.     

Influence of genotype and environment on the content of 5-n alkylresorcinols,total phenols and on the antiradical activity of whole durum wheat grains

The 5-n-alkylresorcinol (AR) contents of thirty different cultivars of durum wheat grown in two years (2009 and 2010) in two Italian locations were determined and related to the total soluble phenolic content (TPC) and antiradical activity (AA). On average, AR and TPC ranged from 161.3 to 405.8 μg/g (dry matter, DM) and from 19.0 to 192.4 μg/g (DM), respectively. AA (EC₅₀ values) ranged from 70.9 to 289.2 mg of dry whole milled wheat grain (DM). The results showed that the environment (E) and the genotype (G), as well as their interactions (G × E), significantly influenced the phytochemical profiles of the samples. The contribution of G × E to the total variance was much lower than that due to the separate effects (G and E). Principal component analysis identified genotypes that were richer in ARs and more stable across environments. There were significant negative correlations between ARs and TPC (p < 0.05) and between TPC and AA (p < 0.01), but not between ARs and AA. Graphical representation was efficient in summarizing the overall antiradical profiles of the durum wheat grain in each environment.     

Antifungal activity of flavonoids from Heteropterys byrsonimifolia and a commercial source against Aspergillus ochraceus: In silico interactions of these compounds with a protein kinase

To contribute to the development of new methods to reduce the contamination of coffee beans with Aspergillus ochraceus and ochratoxin A, a toxin produced by this fungus, the present work initially aimed to select plant extracts active against A. ochraceus. Among the extracts from 43 plant species, the most active was the one obtained from leaves of Heteropterys byrsonimifolia. This extract was subjected to a fractionation process that resulted in the purification of four flavonoids, among which the most active against the fungus was rutin, which presented a minimal inhibitory concentration (MIC, 32.5 μg/mL) close to the value obtained for the commercial fungicide benzalkonium chloride (7.84 μg/mL). In vitro studies with the isolated flavonoids and other four from commercial sources showed that the MIC for the flavonoid chrysin is equal to that observed for rutin, and results from an in silico study suggested that these flavonoids act against A. ochraceus by binding to a protein kinase produced by this fungus. Consequently, this enzyme and the studied flavonoids are potentially useful for the development of new products to control A. ochraceus in coffee beans.     

Crop hosts and genotypic resistance influence the biological activity of Bacillus thuringiensis towards Helicoverpa armigera

Studies on the influence of genotypic resistance on biological activity of a commercial formulation of Bacillus thuringiensis (Bt) and pure Bt toxin Cry1Ac were carried out to develop appropriate strategies for pod borer, Helicoverpa armigera management in chickpea, sorghum, pigeonpea and cotton. The interaction effects of host plant resistance and biological activity of commercial Bt/Cry1Ac were studied by incorporating the lyophilized tissues of chickpea leaves, milk stage sorghum grain, pigeonpea pods and cotton squares into the artificial diet with and without Bt formulation or Cry1Ac. The H. armigera larval weights were significantly lower in insects reared on diets with square powder of the insect - resistant Bt-cotton RCH 2 + Bt/Cry1Ac and pod powder of insect - resistant pigeonpea genotype, ICPL 332WR + Bt/Cry1Ac as compared to the larvae reared on diets with leaf powder of H. armigera susceptible chickpea genotype, ICCC 37 and the standard artificial diet. Pupation and adult emergence were significantly lower in insects reared on diets with tissues of pod borer-resistant genotypes + Bt/Cry1Ac as compared to insects reared on diets with tissues of the insect susceptible genotypes + Bt/Cry1Ac. Insects reared on diets containing insect-resistant and -susceptible genotypes of sorghum, pigeonpea and cotton and pod borer-resistant genotype of chickpea (ICC 506EB) + Bt/Cry1Ac did not lay any eggs. However, eggs were laid by the insects reared on diets containing pod borer-susceptible genotype of chickpea, ICCC 37 and on the standard artificial diet + Bt/Cry1Ac. The insects reared on diets with sorghum genotype, ICSV 745, and Bt-cotton, RCH 2 without Bt/Cry1Ac also did not lay eggs. The results suggested that Bt/Cry1Ac is more effective for management of H. armigera when deployed in combination with insect-resistant genotypes of cotton, chickpea, pigeonpea and sorghum.     

Genotype × environment interactions for shoot fly resistance in sorghum (Sorghum bicolor (L.) Moench): Response of recombinant inbred lines

Sorghum shoot fly (Atherigona soccata) is a serious pest that destabilizes the performance of sorghum cultivars and ultimately reduces sorghum production in many parts of the world. Identifying sorghum genotypes with stable resistance to shoot fly is important as it helps to reduce the cost of cultivation and stabilizes yields. In the present study, our objective was to identify stable shoot fly resistant genotypes among 385 recombinant inbred lines (RILs) of a cross between a susceptible parent and a resistant parent. We evaluated this set of RILs in eight environments over three years (2006-2008) for shoot fly resistance and component traits. Non-significant genotype-environment (G × E) linear component and significant pooled deviation for deadheart percentage indicated that the performance of genotypes was unpredictable over the environments. However, five lines had deadheart percentages much less than the population mean with regression coefficient (bi) values close to unity, and non-significant deviation from regression, indicating that they have stable shoot fly resistance and are well adapted to all the environments. Additive main effect and multiplicative interaction (AMMI) analysis partitioned main effects into genotype, environment and G × E interacts with all the components showing highly significant effects (p < 0.001). Environment had the greatest effect (69.2%) followed by G × E interactions (24.6%) and genotype (6.2%). Low heritability and high environmental influence for deadheart percentage suggested that shoot fly resistance is a highly complex character, emphasizing the need for marker assisted selection. We observed transgressive variation in the RIL population for all the traits indicating the contribution of alleles for resistance from both resistant and susceptible parents. Since the alleles for shoot fly resistance are contributed by both resistant and susceptible parents, efforts should be made to capture favourable alleles from resistant and susceptible genotypes.     

Physicochemical assessment and bioactive properties of condensed distillers solubles,a by-product from the sorghum bio-fuel industry

Large volumes of condensed distillers solubles (CDS) are generated as by-products, from the sorghum bioethanol industry. The objective was to assess the physico-chemical and bioactive properties of CDS. The unfractionated CDS showed the highest content of phenolic compounds (16 mg GAE/g), antioxidant (522 μM Trolox/g) and antimicrobial activity (MIC 1%(w/v) against Campylobacter spp.) compared to its extracts. The water and methanol extracts also showed high levels of phenolic compounds and antioxidant activity (11.6 and 9.2 mg GAE/g and 349 and 409 μM Trolox/g respectively), followed by ethanol and acetone extractions (7.5 and 6.6 mg GAE/g; 337 and 346 μM Trolox/g respectively). A positive correlation was revealed between total phenol and antioxidant activity. The main phenolic compounds found in the extracts were protocatechuic acid, 4-hydroxybenzoic acid, taxifolin, ferulic acid, cinnamic acid and p-coumaric acid. This study indicates the potential of using CDS as a functional ingredient for other food and feed applications.     

Antifeedant and toxic effects of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni

We investigated the feeding deterrent effects and toxicity of naturally occurring and synthetic quinones to the cabbage looper, Trichoplusia ni. Feeding deterrent effects were determined via a leaf disc choice bioassay. Based on DC₅₀ values, 1,4-naphthoquinone was the most active antifeedant (DC₅₀ = 1.8 μg/cm²) followed by juglone (DC₅₀ = 2.1 μg/cm²), 2-methoxy-1,4-naphthoquinone (DC₅₀ = 2.6 μg/cm²), plumbagin (DC₅₀ = 3.3 μg/cm²), and 2,3-dimethoxy-5-mehtyl-1,4-benzoquinone (DC₅₀ = 4.2 μg/cm²) in third instar cabbage looper larvae. 2-Bromo-1,4-naphthoquinone, 2-chloro-3-morpholino-1,4-naphthoquinone, 1,8-dihydroxy-anthraquinone, 2-methyl-1,4-naphthoquinone and naphthazarin had DC₅₀ values ranging from 8.4 to 10.1 μg/cm². Juglone and plumbagin were able to provide protection to intact cabbage plants in a greenhouse experiment. Cabbage looper larvae consumed less leaf area and weighed less on cabbage plants treated with either of these naturally occurring quinones. Most of the quinones demonstrated levels of antifeedant activity greater than neem, a positive control, in laboratory bioassays. The level of activity for juglone was comparable to neem in the greenhouse experiment. There was also a reduction in the number of larvae on treated plants compared with the negative control. Structure-activity relationships suggest that the antifeedant effects of the tested quinones depend on the number and position of hydroxyl and methoxyl substituents of quinones. Most of the quinones were of medium-low toxicity to third instar cabbage looper larvae via topical administration. Some of these quinones could have potential for development as commercial insect control agents targeting the feeding behavior of insects with minimal toxicity, provided that their impacts on non-target organisms and environment are minimal.     

Analysis of host plant resistance to multiple Fusarium species associated with stalk rot disease in sorghum [Sorghum bicolor (L.) Moench]

Fusarium spp. is among the largest and most important pathogen groups that attack major grain crops including sorghum. The objectives of this study were to compare the virulence of Fusarium spp. associated with sorghum and examine the mode of resistance of genotypes to the disease. Eight Fusarium species – F. verticillioides, F. thapsinum, F. andiyazi, F. proliferatum, F. nyagamai, F. pseudoanthophilum, F. brevicatenulatum, and F. pseudonygamai – were studied using three sorghum genotypes under greenhouse condition. Three of these pathogens (F. verticillioides, F. thapsinum, and F. andiyazi) were selected for genetic analysis of resistance under field conditions. Sorghum genotypes with contrasting stalk rot reactions were selected for use in both the greenhouse and field experiments. Two weeks after flowering, plants were inoculated with liquid inoculum culture (5 × 10⁴ conidia ml⁻¹) of the different pathogens. Plants were harvested 4 weeks after inoculation and rated for disease severity on the basis of lesion length and number of nodes crossed by the lesion. Among the pathogens, F. thapsinum resulted in consistently higher disease scores in all genotypes under all environments. Likewise, genotype SC599 showed the greatest and most stable resistance as inbred as well as in hybrid combinations as shown by consistently high GCA for resistance to all pathogen species. We recommend that future screening exercises for Fusarium stalk rot resistance utilize F. thapsinum as the causal organism and include the resistant genotype SC599 as a control.     

Small-scale mashing procedure for predicting ethanol yield of sorghum grain

A small-scale mashing (SSM) procedure requiring only 300 mg of samples was investigated as a possible method of predicting ethanol yield of sorghum grain. The initial SSM procedure, which was conducted similarly to the mashing step in a traditional fermentation test, hydrolyzed just 38.5–47.2% of total sorghum starch to glucose. The initial procedure was simplified to contain only one liquefaction step, which did not influence subsequent saccharification. Thereafter, parameters such as temperature, pH, enzyme dosage, and saccharification time were optimized. Results showed that 91.2–97.5% of the total starch in 18 sorghum hybrids had been hydrolyzed to glucose using the following conditions: liquefaction at 86 °C for 90 min, 20 μL of α-amylase per 30 g of sample; pH adjustment by adding 50 μL of 2 M acetate buffer at pH 4.2 to each microtube; saccharification at 68 °C for 90 min, 200 μL of amyloglucosidase per 30 g of sample. There were strong linear correlations between completely hydrolyzed starch (CHS) from SSM and ethanol yields from both traditional (R² = 0.86) and simultaneous saccharification and fermentation (SSF, R² = 0.93) procedures. CHS was a better indicator for predicting ethanol yield in fermentation than total starch.     

In vitro starch digestibility and predicted glycaemic indexes of buckwheat,oat, quinoa,sorghum, teff and commercial gluten-free bread

The in vitro starch digestibility of five gluten-free breads (from buckwheat, oat, quinoa, sorghum or teff flour) was analysed using a multi-enzyme dialysis system. Hydrolysis indexes (HI) and predicted glycaemic indexes (pGI) were calculated from the area under the curve (AUC; g RSR/100g TAC*min) of reducing sugars released (RSR), and related to that of white wheat bread. Total available carbohydrates (TAC; mg/4 g bread “as eaten”) were highest in sorghum (1634 mg) and oat bread (1384 mg). The AUC was highest for quinoa (3260 g RSR), followed by buckwheat (2377 g RSR) and teff bread (2026 g RSR). Quinoa bread showed highest predicted GI (95). GIs of buckwheat (GI 80), teff (74), sorghum (72) and oat (71) breads were significantly lower. Significantly higher gelatinization temperatures in teff (71 °C) and sorghum flour (69 °C) as determined by differential scanning calorimetry (DSC) correlated with lower pGIs (74 and 72). Larger granule diameters in oat (3–10 μm) and sorghum (6–18 μm) in comparison to quinoa (1.3 μm) and buckwheat flour (3–7 μm) as assessed with scanning electron microscopy resulted in lower specific surface area of starch granules. The data is in agreement with predictions that smaller starch granules result in a higher GI.     

In vitro starch digestibility and predicted glycaemic indexes of buckwheat,oat, quinoa,sorghum, teff and commercial gluten-free bread

The in vitro starch digestibility of five gluten-free breads (from buckwheat, oat, quinoa, sorghum or teff flour) was analysed using a multi-enzyme dialysis system. Hydrolysis indexes (HI) and predicted glycaemic indexes (pGI) were calculated from the area under the curve (AUC; g RSR/100g TAC*min) of reducing sugars released (RSR), and related to that of white wheat bread. Total available carbohydrates (TAC; mg/4 g bread “as eaten”) were highest in sorghum (1634 mg) and oat bread (1384 mg). The AUC was highest for quinoa (3260 g RSR), followed by buckwheat (2377 g RSR) and teff bread (2026 g RSR). Quinoa bread showed highest predicted GI (95). GIs of buckwheat (GI 80), teff (74), sorghum (72) and oat (71) breads were significantly lower. Significantly higher gelatinization temperatures in teff (71 °C) and sorghum flour (69 °C) as determined by differential scanning calorimetry (DSC) correlated with lower pGIs (74 and 72). Larger granule diameters in oat (3–10 μm) and sorghum (6–18 μm) in comparison to quinoa (1.3 μm) and buckwheat flour (3–7 μm) as assessed with scanning electron microscopy resulted in lower specific surface area of starch granules. The data is in agreement with predictions that smaller starch granules result in a higher GI.     

Comparison of the requirements and utilization of nitrogen by genotypes of sorghum (Sorghum bicolor (L.) Moench), and nodulating and non-nodulating groundnut (Arachis hypogaea L.)

Nitrogen requirements and utilization of mineral nitrogen (N) by sorghum and groundnut were compared. At the maximum N use level, sorghum genotypes showed greater N use efficiency (120 kg biomass/kg N harvested) than groundnut genotypes (36 kg biomass/kg N harvested). Using a non-nodulating groundnut genotype (Non-nod) or sorghum as controls for soil N uptake, the amounts of N₂ fixed by the nodulated groundnut genotypes were estimated to be 183–190 kg N/ha. Nitrogen fertilization increased harvest index and percentage N translocated to seeds in sorghum genotypes, but decreased harvest index and had variable effects on percentage N translocated to seed in groundnut genotypes. Leaf nitrate reductase activity (NRA) and nitrate content in the leaves of two sorghum genotypes, one nodulating, and ‘Non-nod’ groundnut genotypes were also compared. The concentration of nitrate was lower in sorghum than in groundnut leaves, but NRA was higher in sorghum. It is suggested that either NRA in the groundnut leaves has relatively lower affinity for the substrate (higher Km, the Michaelis-Menton constant) or higher nitrate is required for the induction of nitrate reductase in groundnut than in sorghum. This implies that groundnut is a poor utilizer of fertilizer nitrogen.     

Nitrogen and sulfur effects on hard winter wheat quality and asparagine concentration

Grain protein concentration and composition are key factors affecting winter wheat quality and are influenced by wheat genotype, available fertility, and growing conditions. These same parameters can affect free asparagine concentration in grain, and elevated asparagine can lead to acrylamide production in baked food products, which can be a health concern. The objectives of this study were to determine the effect of genotype, nitrogen (N), and sulfur (S) fertility on protein concentration, protein quality, dough rheology, and asparagine concentration in winter wheat grown on S-deficient soils. Treatments were arranged in a 3 × 2 × 4 factorial design in 2017 and 3 × 2 × 5 factorial design in 2018. There were three levels of N (56, 101 and 146 kg ha⁻¹), two levels of S (0 and 22 kg ha⁻¹), four levels of genotype in 2017, and five levels of genotype in 2018. Protein composition was evaluated as the percent polymeric protein using size exclusion high performance liquid chromatography. In both years, the ratio of polymeric to monomeric protein was increased by sulfur fertilization. Solvent retention capacity (SRC) was evaluated using the whole grain lactic acid-sodium dodecyl sulfate test. In 2018, S application increased the SRC by 217%–308%. However, in 2017, SRC improvement was limited to two genotypes and was modest, likely a consequence of the reduced protein concentration in S-treated plots. Free asparagine concentration averaged 9.8 μmol/g and 20.9 μmol/g in 2017 and 2018, respectively. Asparagine concentration in grain was affected by N, S, genotype, and their interactions. Sulfur application substantially reduced asparagine concentrations in both years. Dough rheology was evaluated in the 2018 trial using the farinograph test. Sulfur application increased average farinograph stability from 9.2 min to 14.6 min. Farinograph stability was effectively predicted by the SRC test (R² = 0.78). These results demonstrate the importance of ensuring adequate S fertility in winter wheat production.     

Evidence of genetic transmission of antibiosis and antixenosis resistance of sorghum to the spotted stemborer, Chilo partellus (Lepidoptera: Pyralidae)

Spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), is the most important pest of sorghum in Asia and south and eastern Africa. Host plant resistance is an important control tactic for controlling this pest. Two breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 with their parents, resistant and susceptible genotypes were evaluated in the field, glasshouse and laboratory for different resistance parameters. Breeding lines and genotypes varied significantly in foliar damage ratings, percentage of stem length tunneled, percentage of plants with deadhearts, larval survival, larval and pupal weights, larval and pupal duration, and percentage pupation and adult emergence in diets amended with leaf powder of different sorghum genotypes. The breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 showed antixenosis and antibiosis to C. partellus in terms of reduced eggs per plant, larval survival and development. The levels of antixenosis and antibiosis of both breeding lines were similar to their resistant parents. Results indicate that transmission of characteristics responsible for resistance to the progeny from the resistant parent occurred.     

Reduction of phytate content while preserving minerals during whole grain cereal tempe fermentation

The effects of different pretreatments on phytate and mineral contents were investigated in whole grain barley and oat tempe fermented with Rhizopus oligosporus. Different varieties of barley and oats were exposed to pretreatments such as pearling, rolling, moistening, autoclaving and soaking before fermentation. Pearling was the most effective pretreatment for reduction of phytate content for both oats and barley. Nevertheless, mineral contents were reduced, and most likely cell wall rich fractions were also reduced by this process. In the first experiments the phytate content reduction in the oats and barley samples were reduced by 74% (3.3 μmol/g, d.m.) and 89% (1.4 μmol/g, d.m.), respectively. However, to improve iron absorption the phytate levels should not exceed 0.5 μmol/g, and further phytate degradation was necessary. Therefore, in the final experiments barley samples were exposed to an optimised process with prolonged soaking at a higher temperature and the pearling residues were returned before fermentation. When the outer layers of the barley kernels were returned before fermentation the phytate content was successfully reduced by 97% to 0.4 μmol/g (d.m.) and Fe and Zn levels were well preserved.     

Electrophoretic analysis of malting degradability of major sorghum reserve proteins

Proteolysis is vital to the generation of amino acids and short peptides during malting. The qualitative and quantitative effects of malting on proteolytic digestion were investigated for 11 Botswana sorghum cultivars. Protein hydrolysis was influenced by sorghum grain cultivar. All protein fractions were degraded, although the extents of their digestion appeared cultivar-dependent. The most significant changes in total and free kafirins occurred among the HMW aggregates while the 45 kDa dimer appeared the most recalcitrant. Free kafirin monomers were digested in variety-defined manner; α-kafirin faded the most (ca. 82%) in Phofu, but appeared least digested (≤10%) in Lekgeberwa; β-kafirin faded the most in Phofu and Segaolane (90–94%) but only 46% in Lekgeberwa. Overall, α-kafirin appeared the least digested of the free monomers. The proportion of free kafirin accounted for by the 45 kDa and monomeric kafirins increased in all malts (except Lars Vyt and Mafia), probably due to protein depolymerisation. Grain variety significantly influenced (p < 0.001) malt FAN levels. Mean FAN values were highest in Segaolane (225 mg/100 g) followed by Sefofu, Town and BSH-1, but lowest in Mafia (96.9 mg/100 g). Results indicate wide variability in the proteolytic malting digestibility of the eleven sorghum cultivars.     

Comparison of different rice flour- and wheat flour-based butter cookies for acrylamide formation

Acrylamide (AcA) contents of different rice flour- and wheat flour-based butter cookies baked at 130 °C for 20, 55, or 90 min were investigated. AcA contents of different flour-based cookies increased with baking time. Color parameters in terms of CIE L*, b*, C*, and ΔE values showed significant opposite correlation to the AcA formation in each of the raw flour cookie. The cookies based on white rice flour had the lowest AcA contents ranging from not detectable (ND) to 204 μg/kg, followed by cookies based on brown rice flour (ND to 450 μg/kg), white wheat flour (155 μg/kg to 661 μg/kg), and whole wheat flour (306 μg/kg to 982 μg/kg). Considerably lower AcA levels were found in the rice flour-based cookies than in the wheat flour-based cookies, as well as in the milled flour-based cookies than in the whole-grain cookies. Although the flour source was considered to play a primary role in determining the AcA content, AcA content was apparently not dependent on the quantities of reducing sugars and free asparagine in the starting raw flour and cookies during baking. In summary, given its reducing potential for AcA formation, rice flour could be used in the production of cookies safe from heat-induced contaminants.     

Stover quality of dual-purpose sorghums: genetic and environmental sources of variation

Improvement of the nutritive value of dual-purpose sorghum (Sorghum bicolor (L.) Moench) stover is an important objective for the semi-arid tropics where sorghum crop residue is extensively used for livestock feed. To identify the relative importance of genetic and environmental sources of variation for nutritive value, leaves and stems of six diverse dual-purpose sorghum cultivars were evaluated for in vitro gas production (Gas48hr), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, nitrogen, and ash contents under two fertility and two plant-density regimes during 2 years in India. Substantial genotypic differences were observed for stem Gas48hr (25.7 to 33.0 ml in 200 g⁻¹ dry matter (DM)) and NDF (564–687) content. Gas48hr and NDF content of stems exhibited more promise as selection criteria than those of leaves, as stems showed larger portion of variation attributed to genotypes, relatively less genotype by environment (GE) interactions, and were closely related to whole-plant values. Year, nitrogen fertilization and plant density showed very little influence on Gas48hr, NDF or ADF of leaves and stems. Gas48hr exhibited substantial GE interactions with all environmental factors, indicating the need for multi-environment testing to achieve progress.