Optimization of tannin-containing sorghum bran addition to gluten-free bread

Ingredients used to enhance sensory quality of gluten-free (GF) bread often lack in nutrients. This presents nutritional challenges for celiac-positive individuals and fails to meet expectations of healthfulness for non-celiac GF consumers. Sorghum (Sorghum bicolor L. Moench) flour can provide acceptable GF bread properties, and tannin-containing varieties contain antioxidants concentrated in the bran along with dietary fiber. Using a central composite design, tannin-containing sumac sorghum bran, gum (xanthan + guar), and water levels were optimized in a GF sorghum-based bread formulation. Loaf specific volume and gas cells/cm² were maximized while minimizing hardness and cell wall thickness. The optimum formulation containing 14.2% sorghum bran, 1% gum, and 145% water (flour basis) effectively increased dietary fiber in bread to 13.4% (considered "high fiber") and showed oxygen radical absorbance capacity of 61.6 µmol TE/g. This optimum formulation did not differ from a sorghum flour-based control bread in consumers' (N = 100) liking of color, texture, flavor, overall acceptability, nor willingness to buy (WTB). All mean hedonic scores (numbered 9-point scale) were above 5, whereas average WTB was 4.7 for the optimum formulation and 4.6 for the control (9-point Likert scale) among consumers varying in GF bread consumption habits. Perceived bread bitterness was low (averaging 2.85 on 9-point intensity scale), did not vary between samples despite marked differences in antioxidant capacity, and was not correlated with WTB. When utilizing effective optimization models with key functional ingredients, sumac sorghum bran addition can enhance dietary fiber and antioxidant potential in sorghum-based GF breads without compromising quality attributes.

Stable sorghum grain quality QTL were identified using SC35 × RTx430 mapping population

Understanding the genetic control and inheritance of grain quality traits is instrumental in facilitating end-use quality improvement. This study was conducted to identify and map quantitative trait loci (QTL) controlling protein, starch, and amylose content in grain sorghum [Sorghum bicolor (L.) Moench] grown under variable environmental conditions. A recombinant inbred line (RIL) population derived from a cross between RTx430 and SC35 was evaluated in six environments across Hays and Manhattan, KS. Significant variation was observed in genotype, environment, and genotype × environment interaction for all three quality traits. Unlike the RILs, the two parental lines did not show significant differences for these traits. However, significant transgressive segregation was observed for all traits resulting in phenotypic performance extending beyond the two parents. A total of seven protein, 10 starch, and 10 amylose content QTL were identified. Chromosomal regions and phenotypic variation (PVE) of QTL were variable across growing conditions. Quantitative trait loci hotspots for all three traits were detected on chromosomes 1 (115.2-119.2 cM) and 2 (118.2-127.4 cM). Candidate gene analysis indicated that these QTL hotspots were conditioned by several transcription factors, such as Cytochrome P450 and basic helix-loop-helix DNA binding protein, which regulate starch and protein accumulation in the grain. The identified genomic regions and underlying candidate genes provide a starting point for further validation and marker-assisted gene pyramiding to improve sorghum grain quality.

Effects of protein digestion on in vitro digestibility of starch in sorghum differing in endosperm hardness and flour particle size

In vitro digestibility of starch in sorghum grains differing in endosperm hardness and flour particle size was investigated. The starch digestibility increased as the particle size of flour decreased, but no clear trend was observed in digestibility of starch in sorghum flours milled from grains with different hardness. The protein matrix affected the digestion of starch. The pH value (2.0 vs. 1.3) was a critical factor affecting protein digestion. Optimum pH (pH 2.0 for pepsin) digested more protein, resulting in a greater digestion of starch. Resistant starch (RS) content was 8.5-26.3% in isolated sorghum starch but higher (10.6-29.5%) in sorghum flours. Protein digestibility decreased after cooking while starch digestibility increased compared to native sorghum flours; disulfide bonds formed between protein molecules. RS content of cooked sorghum flour was much higher without pepsin treatment (16.93-23.99%) than that of cooked sorghum flour with pepsin treatment (4.86-12.53%).

Enhancing Sorghum Yield Through Efficient Use of Nitrogen - Challenges and Opportunities

Sorghum is an important crop, which is widely used as food, forage, fodder and biofuel. Despite its natural adaption to resource-poor and stressful environments, increasing yield potential of sorghum under more favorable conditions holds promise. Nitrogen is the most important nutrient for crops, having a dynamic impact on all growth, yield, and grain-quality-determining processes. Thus, increasing nitrogen use efficiency (NUE) in sorghum would provide opportunities to achieve higher yield and better-quality grain. NUE is a complex trait, which is regulated by several genes. Hence, exploring genetic diversity for NUE can help to develop molecular markers associated with NUE, which can be utilized to develop high NUE sorghum genotypes with greater yield potential. Research on improving NUE in sorghum suggests that, under water-deficit conditions, traits such as stay-green and altered canopy architecture, and under favorable conditions, traits such as an optimized stay-green and senescence ratio and efficient N translocation to grain, are potential breeding targets to develop high NUE sorghum genotypes. Hence, under a wide range of environments, sorghum breeding programs will need to reconsider strategies and develop breeding programs based on environment-specific trait(s) for better adaptation and improvement in productivity and grain quality. Unprecedented progress in sensor-based technology and artificial intelligence in high-throughput phenotyping has provided new horizons to explore complex traits in situ, such as NUE. A better understanding of the genetics and molecular pathways involving NUE, accompanied by targeted high-throughput sensor-based indices, is critical for identifying lines or developing management practices to enhance NUE in sorghum.

AB0289 PATIENT REPORTED PHYSICAL HEALTH COMPARED TO CLINICIAN RECORDED BILAG-2004 MUSCULOSKELETAL SYSTEM SCORES – DISCORDANCE BETWEEN PATIENTS AND CLINICIANS

Background:

The musculoskeletal organ system BILAG-2004 (MSK BILAG) assessment is of critical importance in SLE clinical trials. Severe active polyarthritis, MSK BILAG A, by definition includes significant impairment of basic activities of daily living (ADLs), as opposed to MSK BILAG C, D, or E where ability to perform ADLs is expected to be preserved. In clinical trials, BILAG is scored by clinicians without formal review of patient reported outcomes (PROs). The Physical Health domain of the LupusQoL (LQol PH) (range 0 – 100) can be used to assess the patient’s physical function and ADLs. LQoL PH score thresholds defining impairment severity have not been established; however, a transformed LQoL PH score ≤50 suggests more impaired function, which would not be expected in MSK BILAG C, D, or E. Conversely, a score >50 implies no major issues with ADLs, which would be contradictory to the definition of MSK BILAG A.

Objectives:

To assess correlation of patient reported LQoL PH with MSK BILAG scores recorded by clinicians at various timepoints using data from the phase 3 TULIP studies 1,2 and to investigate the percent of discordance between patients and clinicians.

Methods:

Data from TULIP 1 and 2 studies (anifrolumab 300 mg and placebo arms) were pooled to evaluate the relationship between LQoL PH and MSK BILAG scores at baseline, weeks 24 and 52 using Spearman correlations as post-hoc analysis. Mean LQoL PH scores were assessed for each MSK BILAG category at the three timepoints using one-way ANOVA. Percent of patients with MSK BILAG A and LQoL PH scores >50 and patients with MSK BILAG C, D, or E and LQoL PH scores ≤50 was calculated at baseline, week 24 and 52. MSK BILAG B was excluded from the analysis because discordance could not be easily defined for this category compared with the more extreme MSK BILAG categories.

Results:

Total of 690 patients were included in the pooled analysis (Table 1). Significant correlations between LQoL PH and MSK BILAG scores were found at each time point (nominal p<0.0001); this relationship became stronger over time. Mean LQoL PH scores were different in each MSK BILAG category, with the highest in MSK BILAG D/E and the lowest in the MSK BILAG A category, thus confirming the discriminatory ability of the LQoL PH (Table 1).

Table 1.

Correlation coefficients (CC) between LQoL PH and MSK BILAG scores, and mean LQoL PH scores with standard deviations (SD) per each MSK BILAG category at baseline, weeks 24 and 52.

BaselineWeek 24Week 52CCNCCNCCNTotal Population-0.25690-0.36626-0.41552MSK BILAGMean LQoL PH Score (SD)Mean LQoL PH Score (SD)Mean LQoL PH Score (SD)0 (D/E)69.3 (24.7)1774.2 (22.1)18674.5 (21.3)2371 (C)62.3 (25.4)6064.0 (23.9)23360.6 (22.5)1848 (B)56.6 (24.4)39855.1 (24.2)16351.3 (24.3)10512 (A)44.9 (25.8)21543.9 (25.9)4444.2 (26.2)26

At baseline, 40% of patients who were assessed by clinicians as having MSK BILAG A reported minimal impairment in physical function and ADLs (LQoL PH >50) and 24.1% who had MSK BILAG C, D, or E reported difficulties with ADLs (LQoL HP ≤50), suggesting discordance between patients and clinicians. This discordance slightly decreased over time (Figure 1).

Figure 1.

Percent of patients with MSK BILAG A and LQoL PH scores >50 and patients with MSK BILAG C, D, or E and LQoL PH scores ≤50 at baseline, weeks 24 and 52.

Conclusion:

Patient reported LQoL PH scores correlated with MSK BILAG scores and showed discriminant validity for MSK BILAG scores. Greater discordance was seen between LQoL PH and MSK BILAG A compared with C, D, or E. These findings suggest a need for further investigation of a role for PROs in MSK BILAG scoring. Formal review of PROs by clinicians during MSK BILAG assessment could be considered in future SLE clinical trials.

References:

[1]Furie R et al. Lancet 2019

[2]Morand EF et al. N Engl J Med 2020

Acknowledgements:

This study was sponsored by AstraZeneca.

Disclosure of Interests:

Ewa Olech Speakers bureau: Abbvie, Amgen, Merck, Pfizer, and UCB, Grant/research support from: BMS, Donald Stull: None declared, Betsy Williams: None declared, Stephanie Bean: None declared, Gabriel Abreu Employee of: AstraZeneca, Erik Schwetje Employee of: AstraZeneca, Raj Tummala Employee of: AstraZeneca, Sean O’Quinn Shareholder of: AstraZeneca, Employee of: AstraZeneca

Identification of gluten-like proteins in selected pod bearing leguminous tree seeds

The protein composition, molecular weight distribution, and rheological properties of honey locust, mesquite, Kentucky coffee tree, and carob seed germs were compared against wheat gluten. Polymeric and Osborne fractionation protocols were used to assess biochemical properties. Dynamic oscillatory shear tests were performed to evaluate protein functionality. All samples had similar ratios of protein fractions as well as high molecular weight disulfide linked proteins except for the Kentucky coffee tree germ proteins, which were found to have lower molecular weight proteins with little disulfide polymerization. Samples were rich in acidic and polar amino acids (glutamic acid and arginine,). Rheological analyses showed that vital wheat gluten had the most stable network, while Kentucky coffee seed proteins had the weakest. High molecular weight disulfide linked glutenous proteins are a common, but not universal feature of pod bearing leguminous trees.

Antioxidant Characteristics and Identification of Peptides from Sorghum Kafirin Hydrolysates

Grain sorghum is gaining interest for various uses as a highly sustainable crop. Kafirin is the main storage protein in grain sorghum. However, the antioxidant activities of kafirin hydrolysates have not been systematically investigated. The objectives of this study were to characterize the antioxidative hydrolysates and their ultrafiltrated fractions from sorghum kafirin using chemical assays and model systems and to identify the representative peptides. Kafirin Neutrase hydrolysates displayed promising yield and antioxidant capacity among those prepared with several different proteases. The effects of critical variables including protein substrate content, enzyme-to-substrate ratio, and reaction time on antioxidant production were studied. Selected hydrolysates were further fractionated through ultrafiltration and gel filtration chromatography (GFC). Medium-sized fraction (3 to 10 kDa) revealed relatively higher total phenolic content and stronger antioxidative activities with regard to free radical scavenging activity, metal ion chelating activity, reducing power, and oxygen radical absorbance capacity. In an oil-in-water emulsion system, incorporation of selected fraction of hydrolysates inhibited the formation of primary and secondary oxidation products by 83.03% and 65.59%, respectively, by the end of a 14-day incubation period. Similar oxidation inhibition effect was also observed in a ground meat system. Peptide compositions of the most promising fraction from GFC and reversed-phase high-performance liquid chromatography were identified using matrix-assisted laser desorption ionization-time of flight/time of flight mass spectrometry. PRACTICAL APPLICATION: This study provided a feasible approach to produce peptide antioxidants from sorghum kafirin. The novel naturally derived antioxidants could be potentially used as alternatives or synergetic components to synthetic antioxidants in improving the oxidative stability of various food products.

Genome-Wide Association Mapping of Grain Mold Resistance in the US Sorghum Association Panel

Sorghum [ (L.) Moench] production in warm and humid regions is limited by grain mold disease, which can be caused by a complex of >40 pathogenic and opportunistic fungi. The identification of resistant plants within temperate-adapted germplasm is imperative for the development of better-adapted varieties. The performance of 331 accessions from the previously genotyped sorghum association panel (SAP) was evaluated in four tropical environments. Only 18 accessions showed low seed deterioration and high emergence rates. The resistant accessions showed high variation in seed tannin contents and panicle shape, indicating that grain mold resistance is not associated with a single phenotypic trait. Seed mycoflora analysis recovered pathogenic fungi , , and in both resistant and susceptible accessions. By genome-wide association scans using 268,289 single nucleotide polymorphisms (SNPs), we identified two loci associated with low seed deterioration and another associated with emergence rate. Candidate genes within these loci included one gene () and two genes ( and ) with domains associated with systemic acquired resistance, suggesting that resistance involved pathogen recognition and downstream signaling cascades. This study provides insight into the genetic control of grain mold resistance as well as valuable accessions for breeding programs in temperate environments.

Evaluation of ethanol-based extraction conditions of sorghum bran bioactive compounds with downstream anti-proliferative properties in human cancer cells

Certain foods such as turmeric and green tea have been extensively studied for anticancer properties, while high polyphenol sorghum has not received the same attention. Some bioactive compounds in Sorghum bicolor with anticancer activity have been identified, indicating the further need for research and screening methods of high polyphenol sorghum varieties. This study was aimed at improving the extraction of sorghum bioactive compounds by using food-grade solvents using ethanol and citric acid. We used three sorghum varieties and green tea (GT) as a control. The extraction methods were screened for anti-proliferative properties in HepG2 and HCT-15 cancer cell lines, using a cell viability assay. Extraction conditions were improved for anti-proliferative compounds from a high-phenolic sorghum variety (HP), sumac sorghum (CS), and GT. HP was more effective at inhibiting cell viability than CB, CS, and GT. The results demonstrate an efficient method for extracting sorghum bioactive compounds for future anticancer research using food approved ingredients.

Clinical Trial Implications for Study Participants Accessing Medical Assistance in Dying

The legalization of medical assistance in dying (maid) in June 2016 expanded options for end-of-life care in Canada [...]

Changes in protein and starch digestibility in sorghum flour during heat-moisture treatments

BACKGROUND

Heat-moisture treatment (HMT) has been used to modify properties of sorghum starches. However, information is limited on the effects of HMT on the digestibility of starch and the concurrent changes in protein in sorghum flour. The objectives of this research were to identify heat-moisture conditions to increase the resistant starch (RS) content of sorghum flour and investigate changes in sorghum proteins and starch structure.

RESULTS

Sorghum flours with different moisture contents (0, 125, 200, and 300 g kg^-1 w.b.) were heated at three temperatures (100, 120 and 140 °C) and times (1, 2 and 4 h). HMT of sorghum flour increased its RS level. The flour treated at 200 g kg^-1 moisture and 100 °C for 4 h had a high RS content (221 g kg^-1 vs. 56 g kg^-1 for the untreated flour). Starch was not gelatinized when sorghum flours heated at moisture content of 200 g kg^-1 or below. Sorghum protein digestibility and solubility decreased during HMT. The increase in RS of sorghum flour upon HMT was attributed to enhanced amylose-lipid complexes and heat induced structural changes in its protein fraction.

CONCLUSION

HMT can be used to increase RS content in sorghum flour without gelatinizing its starch, thereby providing sorghum flour with unique food applications. © 2017 Society of Chemical Industry.

Interaction of Sorghum Tannins with Wheat Proteins and Effect on in Vitro Starch and Protein Digestibility in a Baked Product Matrix

Carbohydrates contribute the most dietary calories, which makes starchy foods a logical target for modifying calorie intake. This study investigated the interaction of sorghum bran proanthocyanidins (PA) with proteins during wheat flour tortilla processing and impact on in vitro starch digestibility. Brans from wheat, white (low in phenols), brown (high PA), and black (high monomeric flavonoids) sorghum were used. Changes in phenolic profile, starch, and proteins were evaluated. Dough mixing drastically decreased extractable PA (61-72%) but not monomeric phenolics; higher MW PA decreased the most. The high PA bran dough produced the highest insoluble proteins (460 vs 330 mg/g protein for other sorghum brans) at 25% baker's substitution. The high PA bran tortillas also had higher slow digesting starch and lower rapidly digesting starch than all other bran treatments. Significant sorghum PA-gluten interactions occur during dough mixing that may slow starch digestibility in the baked products.

Bioethics consultation practices and procedures: a survey of a large Canadian community of practice

The literature fails to reflect general agreement over the nature of the services and procedures provided by bioethicists, and the training and core competencies this work requires. If bioethicists are to define their activities in a consistent way, it makes sense to look for common ground in shared communities of practice. We report results of a survey of the services and procedures among bioethicists affiliated with the University of Toronto Joint Centre for Bioethics (JCB). This is the largest group of bioethicists working in healthcare organizations in Canada. The results suggest there are many common services and procedures of JCB bioethicists. This survey can serve as a baseline for further exploration of the work of JCB bioethicists. Common practices exist with respect to the domains of practice, individual reporting relationships, service availability within business hours and the education and training of the bioethicist.

Modulation of kernel storage proteins in grain sorghum (Sorghum bicolor (L.) Moench)

Sorghum prolamins, termed kafirins, are categorized into subgroups α, β, and γ. The kafirins are co-translationally translocated to the endoplasmic reticulum (ER) where they are assembled into discrete protein bodies that tend to be poorly digestible with low functionality in food and feed applications. As a means to address the issues surrounding functionality and digestibility in sorghum, we employed a biotechnology approach that is designed to alter protein body structure, with the concomitant synthesis of a co-protein in the endosperm fraction of the grain. Wherein perturbation of protein body architecture may provide a route to impact digestibility by reducing disulphide bonds about the periphery of the body, while synthesis of a co-protein, with known functionality attributes, theoretically could impact structure of the protein body through direct association and/or augment end-use applications of sorghum flour by stabilizing ß-sheet formation of the kafirins in sorghum dough preparations. This in turn may improve viscoelasticity of sorghum dough. To this end, we report here on the molecular and phenotypic characterizations of transgenic sorghum events that are down-regulated in γ- and the 29-kDa α-kafirins and the expression of a wheat Dy10/Dx 5 hybrid high-molecular weight glutenin protein. The results demonstrate that down-regulation of γ-kafirin alone does not alter protein body formation or impacts protein digestibility of cooked flour samples. However, reduction in accumulation of a predicted 29-kDa α-kafirin alters the morphology of protein body and enhances protein digestibility in both raw and cooked samples.

The effect of intravitreal anti-VEGF agents on peripheral wound healing in a rabbit model

Purpose

To investigate the effect of intravitreal pegaptanib, bevacizumab, and ranibizumab on blood-vessel formation during cutaneous wound healing in a rabbit model and to compare this effect to placebo controls.

Methods

Forty New Zealand albino rabbits underwent full thickness cutaneous wounds using 6-mm dermatologic punch biopsies. The rabbits were assigned to four groups of ten, each receiving intravitreal injections of pegaptanib, bevacizumab, ranibizumab, or no injection (untreated controls). Five rabbits from each group underwent wound harvesting on day 7 and five from each group on day 14. The skin samples were stained with hematoxylin and eosin (HE), Masson’s trichrome (MT), and CD34 for vascular endothelial cells. Semiquantitative evaluation of HE- and MT-stained slides was performed by one pathologist. Quantitative assessment of mean neovascularization (MNV) scores was obtained from five contiguous biopsy margin 400× fields of CD34-stained sections by four independent observers.

Results

Week 1 MNV scores in CD-34 stained sections were: untreated controls: 11.51 ± 4.36; bevacizumab: 7.41 ± 2.82 (P = 0.013); ranibizumab: 8.71 ± 4.08 (P = 0.071); and pegaptanib: 10.15 ± 5.59 (P = 0.378). Week 2 MNV data were: untreated controls: 6.14 ± 2.25; bevacizumab: 7.25 ± 2.75 (P = 0.471); ranibizumab: 4.53 ± 3.12 (P = 0.297); and, pegaptanib: 6.35 ± 3.09 (P = 0.892). Interobserver variability using intraclass correlation coefficient was 0.961.

Conclusions

At week 1, all three anti-VEGF agents had suppressed MNV scores compared to controls. Although not statistically significant, there was an inhibitory trend, particularly with bevacizumab and ranibizumab. These effects were diminished at 2 weeks, reflecting a transition between the proliferative and remodeling phases of wound healing.

Comparison of methods for extracting kafirin proteins from sorghum distillers dried grains with solubles

Use of coproducts generated during fermentation is important to the overall economics of biofuel production. The main coproduct from grain-based ethanol production is distillers dried grains with solubles (DDGS). High in protein, DDGS is a potential source of protein for many bioindustrial applications such as adhesives and resins. The objective of this research was to characterize the composition as well as chemical and physical properties of kafirin proteins from sorghum DDGS with various extraction methods including use of acetic acid, HCl-ethanol and NaOH-ethanol under reducing conditions. Extraction conditions affected purity and thermal properties of the extracted kafirin proteins. Extraction yields of 44.2, 24.2, and 56.8% were achieved by using acetic acid, HCl-ethanol and NaOH-ethanol, respectively. Acetic acid and NaOH-ethanol produced protein with higher purity than kafirins extracted with the HCl-ethanol protocol. The acetic acid extraction protocol produced protein with the highest purity, 98.9%. Several techniques were used to evaluate structural, molecular and thermal properties of kairin extracts. FTIR showed alpha-helix dominated in all three samples, with only a small portion of beta-sheet present. Electrophoresis results showed alpha(1), alpha(2) band and beta kafirins were present in all three extracts. Glass transition peaks of the extracts were shown by DSC to be approximately 230 degrees C. Kafirin degraded at 270-290 degrees C. Size exclusion chromatography revealed that the acetic acid and HCl-ethanol based extraction methods tended to extract more high molecular weight protein than the NaOH-ethanol based method. Reversed phase high-performance liquid chromatography showed that the gamma kafirins were found only in extracts from the NaOH-ethanol extraction method.

Dough rheology and wet milling of hard waxy wheat flours

To realize the full potential of waxy wheat (Triticum aestivum L.), the wet milling properties of waxy wheat flours including their dough-mixing properties were investigated. Flours of six waxy hard wheats, one normal hard wheat ('Karl 92'), and one partial waxy hard wheat ('Trego') were fractionated by the dough-washing (Martin) process, and the yields and recoveries of starch and gluten were compared. When waxy and normal wheat starches each were blended with a wheat gluten to give a mixture containing 14.5% protein, they gave very different mixograms even though the protein was the same in those blends. Waxy wheat starch absorbed more water than normal wheat starch, which apparently retarded hydration of gluten and dough development. Higher water content had to be used for some waxy wheat flours to develop optimum dough. Washing waxy wheat flour dough under a stream of water caused dough to become slack, spread out more on the sieve, and break apart into several pieces, which when thoroughly washed, coalesced into an elastic dough like the controls. By mixing a weak dough with 2% NaCl solution or by adding hemicellulase, stickiness of the dough subsided during the washing step and thereby improved the recovery of the gluten and starch fractions.

Evaluation and characterization of forage Sorghum as feedstock for fermentable sugar production

Sorghum is a tropical grass grown primarily in semiarid and drier parts of the world, especially areas too dry for corn. Sorghum production also leaves about 58 million tons of by-products composed mainly of cellulose, hemicellulose, and lignin. The low lignin content of some forage sorghums such as brown midrib makes them more digestible for ethanol production. Successful use of biomass for biofuel production depends on not only pretreatment methods and efficient processing conditions but also physical and chemical properties of the biomass. In this study, four varieties of forage sorghum (stems and leaves) were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy and X-ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and the enzymatic hydrolysis process. Forage sorghums with a low syringyl/guaiacyl ratio in their lignin structure were easy to hydrolyze after pretreatment despite the initial lignin content. Enzymatic hydrolysis was also more effective for forage sorghums with a low crystallinity index and easily transformed crystalline cellulose to amorphous cellulose, despite initial cellulose content. Up to 72% hexose yield and 94% pentose yield were obtained using modified steam explosion with 2% sulfuric acid at 140 degrees C for 30 min and enzymatic hydrolysis with cellulase (15 filter per unit (FPU)/g cellulose) and beta-glucosidase (50 cellobiose units (CBU)/g cellulose).

Structure and functional properties of sorghum starches differing in amylose content

Starches were isolated from grains of waxy, heterowaxy, and normal sorghum. To study the relationship between starch structure and functionality and guide applications of these starches, amylose content, amylopectin chain-length distributions, gelatinization and retrogradation, pasting properties, dynamic rheological properties, and in vitro enzyme digestion of raw starches were analyzed. Heterowaxy sorghum starch had intermediate amylose content, pasting properties, and dynamic rheological properties. Stress relaxation was a useful indicator of cooked starch cohesiveness. Cooked heterowaxy sorghum starch (10% solids) had a viscoelastic-solid type of character, whereas cooked waxy sorghum starch behaved like a viscoelastic liquid. Amylopectin of normal sorghum starch had a slightly higher proportion of chains with degree of polymerization (DP) of 6-15 (45.5%) compared with amylopectin of heterowaxy starch (44.1%), which had a gelatinization peak temperature 2 degrees C higher than normal sorghum starch. Heterowaxy sorghum starch contained significantly lower rapidly digestible starch (RDS) and higher resistant starch (RS) than waxy sorghum starch.

Grain sorghum is a viable feedstock for ethanol production

Sorghum is a major cereal crop in the USA. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The goal of this research was to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus was to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model (ELCAM) to quantify and prioritize the saving potential from factors identified in this research. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, and formation of amylose-lipid complexes in the mash. A platform ELCAM with a base case showed a positive net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2 million Btu/ac.

Rheological studies utilizing various lots of zein in N,N-dimethylformamide solutions

Rheological studies were carried out on solutions of zein in N,N-dimethylformamide (DMF), where the specific lot of zein, concentration, time, and temperature were varied. DMF is a good solvent for zein, giving clear, relatively low viscosity solutions. It was found that all of the zein solutions behaved in a non-Newtonian fashion. At high concentration and elevated temperature, zein solutions will increase in viscosity with time. A temperature study on the rate of viscosity rise illustrated that at temperatures above 40 degrees C, the rate of viscosity rise increased in a non-Arrhenius fashion. There can be significant lot to lot variations in commercially obtained zein that gives rise to differences in viscosity and rate of viscosity rises. With the samples studied, viscosity was found to double from one lot of zein to another. Size exclusion chromatography suggests that compositional differences between the lots drive the observed differences in viscosity.

pGreen: a versatile and flexible binary Ti vector for Agrobacterium-mediated plant transformation

Binary Ti vectors are the plasmid vectors of choice in Agrobacterium-mediated plant transformation protocols. The pGreen series of binary Ti vectors are configured for ease-of-use and to meet the demands of a wide range of transformation procedures for many plant species. This plasmid system allows any arrangement of selectable marker and reporter gene at the right and left T-DNA borders without compromising the choice of restriction sites for cloning, since the pGreen cloning sites are based on the well-known pBluescript general vector plasmids. Its size and copy number in Escherichia coli offers increased efficiencies in routine in vitro recombination procedures. pGreen can replicate in Agrobacterium only if another plasmid, pSoup, is co-resident in the same strain. pSoup provides replication functions in trans for pGreen. The removal of RepA and Mob functions has enabled the size of pGreen to be kept to a minimum. Versions of pGreen have been used to transform several plant species with the same efficiencies as other binary Ti vectors. Information on the pGreen plasmid system is supplemented by an Internet site (http://www.pgreen.ac.uk) through which comprehensive information, protocols, order forms and lists of different pGreen marker gene permutations can be found.

Accommodation to stationary and moving targets

PURPOSE

To test the hypothesis that the contrast of spectral components of the retinal image specifies ocular focus and controls reflex accommodation.

METHODS

Eight subjects viewed a stationary target at 0, 2.5, and 5 D in a Badal optometer, with longitudinal chromatic aberration (LCA) normal and reversed and in monochromatic (550 nm) light. Accommodation was monitored continuously during 40-s trials. Subjects also viewed the grating target as it moved sinusoidally (1.5 to 2.5 D) at 0.2 Hz under the same three conditions.

RESULTS

Subjects accommodated relatively accurately at all distances in the normal condition; three subjects had difficulty accommodating in monochromatic light at 5 or 0 D, and seven subjects could not maintain focus with LCA reversed. The accommodative response differed significantly in the three chromatic conditions both for stationary and moving targets.

CONCLUSIONS

Relative contrast of long-, middle-, and short-wavelength components of the retinal image specifies ocular focus and drives reflex accommodation.