Synthetic lubricant basestocks from epoxidized soybean oil and Guerbet alcohols

Vegetable oils are biodegradable and therefore good candidates for environmentally friendly base stocks. They have excellent lubricity, but poor oxidation and low temperature stabilities. For this study, synthetic lubricant basestocks with oxidative stabilities and pour points comparable with commercial synthetic lubricant basestocks have been prepared by reacting epoxidized soybean oil with Guerbet alcohols. Four different Guerbet alcohols, C12-, C14-, C16-, and C18-Guerbet alcohols were used. Reaction of epoxidized soybean oil with a Guerbet alcohol in the presence of a catalytic amount of sulfuric acid provided open-ringed products. ¹H NMR has shown that transesterification follows after ring-opening reaction under the given reaction conditions. Two types of ring-opened products, 0%- and 100%-transesterified products, could be obtained under controlled reaction conditions. Pour points of the ring-opened products ranged from −18 to −36 °C without pour point depressant (PPD) and from −21 to −42 °C with 1% of PPD. Acetylation of hydroxy groups in the ring-opened products further lowered pour points that ranged from −27 to −42 °C without PPD and from −30 to −48 °C with 1% of PPD. Oxidative stability was examined using a modified Penn State microoxidation test and compared with those of synthetic lubricant basestocks and mineral oil. Oxidative evaporations of two selected products in the microoxidation test were similar to mineral oil and less than synthetic lubricant-based oils, polyalphaolefin (PAO₄) and diisododecyl adipate. Deposits of these products were similar to synthetic lubricant-based oils and less than mineral oil.     

Physical properties of triglyceride estolides from lesquerella and castor oils

Lesquerella is a developing hydroxy oilseed crop suitable for rotation in the arid Southwestern United States. The hydroxy oil of lesquerella makes it suitable for esterification into triglyceride estolides. The estolide functionality imparts unique physical properties that make this class of materials suitable for functional fluid applications. Lesquerella and castor hydroxy triglycerides were converted to their corresponding estolides by reacting the oils with saturated fatty acids (C2–C18) in the presence of a tin 2-ethylhexanoate catalyst (0.1 wt.%) and utilizing the condensation of hydroxy with corresponding anhydride or heating under vacuum at 200 °C. Two homologous series of estolides for each triglyceride were synthesized for comparison, mono-capped (one hydroxy functionality per triglyceride molecule) and full-capped (all hydroxy functionalities per triglyceride molecule). Physical properties (pour point, cloud point, viscosity, and oxidative stability) were compared for this estolide series. The longer chain saturate capped estolides (C14–C18) had the highest pour points for both mono-capped (9 °C, C18:0) and full-capped (24 °C, C18:0) lesquerella estolides. Castor mono-capped (9 °C) and full-capped (18 °C) triglyceride estolides gave similar properties. However, pour points improved linearly when the shorter saturated fatty acid capping chain lengths were esterified with the hydroxy triglycerides. Lesquerella capped with a C6:0 fatty acid had pour points of −33 °C for the mono-capped and −36 °C for the full-capped and castor had −36 and −45 °C, respectively. Oxidative stabilities of the estolides were compared for oleic, lauric and lauric-hydrogenated mono- and full-capped materials by rotating bomb oxygen test (RBOT). RBOT times for oleic and lauric capped estolides were low and similar with times centered around 15 min. However, when antioxidant (4 wt.%) was added the RBOT times increased to 688 min for the hydrogenated full-capped lesquerella lauric estolide. The antioxidant had little effect on RBOT times when 2 wt.% or less antioxidant was added for all the estolides except those that were hydrogenated. The hydrogenated estolides showed improvements in oxidative stability at all concentrations of antioxidant tested. Viscosity index ranged from 130 to 202 for all estolides with the shorter chain length capped estolides gave the lower viscosity index values. Viscosity at 100 °C ranged from 13.9 to 26.6 cSt and the 40 °C viscosity ranged from 74.7 to 260.4 cSt where the longer chain length capped estolides gave the highest viscosities.     

Synthesis and characterization of hazelnut oil-based biodiesel

The demand for diesel fuel far exceeds the current and future biodiesel production capabilities of the vegetable oil and animal fat industries. New oilseed crops that do not compete with traditional food crop are needed to meet existing energy demands. Hybrid hazelnut oil is just such an attractive raw material for production of biodiesel. Hazelnut oil was extracted from hybrid hazelnuts and the crude oil was refined. Hazelnut oil-based biodiesel was prepared via the transesterification of the refined hazelnut oil with excess methanol using an alkaline catalyst. The effects of reaction temperature, time and catalyst concentration on the yield of diesel were examined, and selected physical and chemical properties of the biodiesel were evaluated. The biodiesel yield increased with increasing temperature from 25 to 65 °C and with increasing catalyst concentration from 0.1 to 0.7 wt%. The increase in yield with reaction time was nonlinear and characterized by an initial faster rate, followed by a slow rate. Hazelnut oil-based biodiesel had an average viscosity of 8.82 cP at 25 °C, which was slightly higher than that of the commercial soy-based diesel (7.92 cP at 25 °C). An approximate 12 °C higher onset oxidative temperature and a 10 °C lower cloud point of hazelnut oil biodiesel than those of its commercial soy counterpart indicated a better oxidative stability and flowability at low temperature. The average heat of combustion of hazelnut oil biodiesel was 40.23 kJ/g, and accounted for approximately 88% of energy content of diesel fuel. The fatty acid composition of hazelnut oil-based biodiesel was the same as the nature oil.     

Synthesis and physical properties of estolides from lesquerella and castor fatty acid esters

Biodegradable, vegetable oil-based lubricants must have better low temperature properties as well as comparable cost to petroleum oils before they can become widely acceptable in the marketplace. The low temperature property usually measured is the pour point (pp), the minimum temperature at which the material will still pour. Viscosity and viscosity index also provide information about a fluid's properties where a high viscosity index denotes that a fluid has little viscosity change over a wide temperature range. Lesquerella oil is a good candidate for its development into a biodegradable lubricant as it is being developed as an alternative crop for the southwestern U.S. The hydroxy site on the fatty acid (FA) makes it a suitable site for esterification to yield estolides. Castor and lesquerella FA esters were combined with different types of saturated, unsaturated, and branched FAs to produce estolides. Castor and lesquerella estolide esters had the best cold temperature properties when capped with oleic (pp = −54 °C for castor and pp = −48 °C for lesquerella) or capped with a branched material, 2-ethylhexanoic acid (pp = −51 °C for castor and pp = −54 °C for lesquerella). As the saturation was increased in the estolide, pour and cloud points also increased. The increased saturation such as in stearic capped estolides allowed for sufficient alkyl stacking of these long saturated chains producing higher pour points. Oxidative stability of the estolides was compared between the oleic-castor estolide 2-ethylhexyl ester and the coco-castor estolide 2-ethylhexyl ester by the rotating bomb oxidation test (RBOT). The RBOT times for both estolides were low with a similar time of about 15 min. However, when the antioxidant package (3.5 wt.%) was added, the RBOT times increased to 403 min for the coco-castor estolide 2-ethylhexyl ester while still retaining its outstanding cold temperature properties, (pp = −36 °C and cp = −30 °C). The viscosity index ranged from 164 to 200 for these new hydroxy FA derived estolide 2-ethylhexyl esters. These oleic-castor and lesquerella estolide esters have displayed far superior low temperature properties (pp = −54 °C) than any other estolides reported to date. Due to the lack of solvent and catalysts, the cost of these estolides should be reasonable and more suitable as a base stock for biodegradable lubricants and functional fluids than current commercial materials.     

Bio-oil production from soybean (Glycine max L.); fuel properties of Bio-oil

Soybean oil cake (SOC) has been studied to produce bio-oil in a fixed-bed pyrolysis unit. The effect of pyrolysis parameters on the product yields and compositions were investigated. The highest bio-oil yield of a ca 25.8 wt.% was obtained at 400 °C pyrolysis temperature with a heating rate of 50 °C/min for particles of 0.425–0.600 mm in size. The various characteristics of bio-oil acquired under these conditions were identified. The empirical formula of bio-oil with a calorific value of 33.6 MJ/kg was established as CH_1.37O_0.15N_0.14. The chemical characterization studies showed that the bio-oil obtained from SOC might be a potentially valuable source as renewable fuel and chemical feedstocks.     

The impact of heating and cooling on the physico-chemical properties of wheat gluten–water suspensions

The rapid visco analysis (RVA) system was used to measure rheological behaviour in 20% (w/v) gluten-in-water suspensions upon applying temperature profiles. The temperature profiles included a linear temperature increase, a holding step, a cooling step with a linear temperature decrease to 50 °C, and a final holding step at 50 °C. Temperature and duration of the holding phase both affected RVA viscosity and protein extractability. Size-exclusion and reversed-phase HPLC showed that increasing the temperature (up to 95 °C) mainly decreased glutenin extractability. Holding at 95 °C resulted in polymerisation of both gliadin and glutenin. Above 80 °C, the RVA viscosity steadily increased with longer holding times while the gliadin and glutenin extractabilities decreased. Their reduced extractability in 60% ethanol showed that γ-gliadins were more affected after heating than α-gliadins and ω-gliadins. Enrichment of wheat gluten in either gliadin or glutenin showed that both gliadin and glutenin are necessary for the initial viscosity in the RVA profile. The formation of polymers through disulphide bonding caused a viscosity rise in the RVA profile. The amounts of free sulphydryl groups markedly decreased between 70 and 80 °C and when holding the temperature at 95 °C.     

Properties of dry film lubricants prepared by spray application of aqueous starch–oil composites

Aqueous dispersions of starch–soybean oil (SBO) and starch–jojoba oil (JO) composites, prepared by excess steam jet cooking, form effective dry film lubricants when applied as thick coatings to metal surfaces by a doctor blade. This application method necessitates long drying times, is wasteful, requires the addition of sucrose to promote composite adhesion to the metal surface, and restricts the substrate geometry to planar surfaces. These issues represent important barriers to the commercialization of this aqueous biobased dry film lubricant technology. We now report an air-assisted spray method that uses readily available spray equipment to apply aqueous starch–oil composite dispersions as thin coatings (0.15–2.0 mg/cm²) to metal surfaces quickly and efficiently. Aqueous dispersions of waxy maize starch–oil composites containing either SBO, JO or hexadecane (HD), having 0.020–31.7 wt% oil relative to starch, were applied by air-assisted spraying and could be dried to the touch in approximately 30 s. Additionally, sucrose was found unnecessary for adhesion of the sprayed coatings. Tribological ball-on-flat testing of metal specimens spray coated with starch–SBO, –JO, and –HD composites showed the thin films of starch–SBO and –JO performed better at reducing the coefficient of friction (COF) than the starch–hexadecane composites. A low COF ranging between 0.027 and 0.044 was obtained for the starch–SBO and –JO composites containing 4–5 wt% oil relative to starch. Above 4–5 wt% oil loadings, no further COF reductions were realized. Further results revealed that micrometer-sized oil droplets embedded within the dried starch matrix of the composite film are delivered “on demand”. It appears that when pressure is applied to the dry film lubricant, the starch matrix ruptures and releases the entrained oil to the friction surface.     

Responses of sunflower yield and grain quality to alternating day/night high temperature regimes during grain filling: Effects of timing,duration and intensity of exposure to stress

In order to quantify the effects, at different stages during grain filling, of alternating day/night high temperature regimes on sunflower grain yield and quality, heads were exposed to high temperatures during 7 or 6 days starting either 10–12 days after anthesis (daa, HT1), 18 daa (HT2) or 24 daa (HT3). Also, heads were exposed to high temperatures for periods of 2, 4 or 6 days in each of HT1 and HT2. Temperatures covered a range of mean daily grain temperature of 20–40 °C and peak grain temperatures (i.e., those prevailing during the central 5 h of the daylight period) of 26–45 °C. High temperature stress for periods of 4 days or longer produced significant (p < 0.05) reductions in grain yield and grain quality. Early (HT1) exposure to stress reduced yield by 6%/°C above a mean grain temperature threshold of 29 °C; later (HT2 + HT3) exposures reduced yield by 4%/°C above a threshold of 33 °C. These reductions in yield were attributable to reductions in unit grain weight at all positions (periphery, intermediate, central) on the head, and an increase in the proportion of very small (10–30 mg) grains, termed half-full (HF) grains in this paper. In both full and HF grains, stress in either HT1 or HT2 reduced final pericarp weight, associated with fewer number of cell layers and thinner cell walls in the schlerenchyma. High temperatures reduced both the rate and duration of oil deposition in the grain, with the greatest effects being found with early (HT1) exposures. The unsaturation (oleic acid/linoleic acid) ratio of oil from mature grain was altered only when exposure to heat stress overlapped with the cessation of deposition of storage lipids. The effects of duration and intensity of heat stress on relative (to control) grain yield and oil content could be reasonably summarized using a linear response to cumulative hourly heat load calculated with a base temperature of 30 °C. We conclude that: (i) 4 days of alternating day/night temperatures resulting in mean daily grain temperatures of >30 °C can reduce sunflower grain yield and quality; (ii) the magnitude of these effects is strongly dependent on the timing of exposure and their nature on the grain growth processes active at the time of stress; and (iii) an hourly heat load (base = 30 °C) provides a useful integrative estimator of the effects of exposure to heat stress on grain yield and oil content for a given phase of grain filling.     

Synthesis and physical properties of mono-estolides with varying chain lengths

Saturated mono-estolide methyl esters and enriched saturated mono-estolide 2-EH esters were synthesized from oleic and different saturated fatty acids under three different synthetic routes. Estolide numbers (EN), the average number of fatty acid units added to a base fatty acid, varied with synthetic conditions. The attempts at obtaining saturated mono-estolide 2-EH esters, EN = 1, via distillation proved to be challenging, which lead to estolide samples with EN > 1 and the pour point values followed the same trend as the high EN estolides. The other synthetic routes provided saturated mono-estolide methyl esters with EN = 1. The resulting pour point values showed a linear relationship between the saturated capping chain length and pour point. As the saturated capping chain length increased the pour points also increased (higher temperatures): C-2 capped ?30 °C, C-10 capped ?12 °C, and C-18 capped 3 °C.The saturated mono-estolide methyl ester viscosities also showed an increase in viscosity at 40 and 100 °C as the saturated chain lengths increased. The viscosities for the C-4 saturated mono-estolide methyl ester was 9.5 cSt at 40 °C and 2.6 cSt at 100 °C, while medium chain length derivations (C-10 saturated mono-estolide methyl ester) were 19.7 cSt at 40 °C and 4.2 cSt at 100 °C, and at the longer chain length derivations (C-18 mono-estolide methyl esters) were 27.6 cSt at 40 °C and 10.7 cSt at 100 °C. In general, a new series of saturated oleic mono-estolide methyl esters were synthesized and physical properties were collected. The physical property data indicated that both chain length and EN affect low temperature properties.     

Large applications of fertilizer N at planting affects seed protein and oil concentration and yield in the Early Soybean Production System

An inverse relationship between soybean [Glycine max (L.) Merr.] seed protein and oil concentration is well documented in the literature. A negative correlation between protein and yield is also often reported. The objective of this study was to determine the effect of high rates of N applied at planting on seed protein and oil. Nitrogen was surface-applied at soybean emergence at rates of 290 kg ha⁻¹ in 2002, 310 kg ha⁻¹ in 2003, and 360 kg ha⁻¹ in 2004. Eight cultivars ranging from Maturity Group II–IV were evaluated under the Early Soybean Production System (ESPS). However, not all cultivars were evaluated in all 3 years. Glyphosate herbicide was used in all 3 years and a non-glyphosate herbicide treatment was applied in 2002. Cultivars grown in 2003 were also evaluated under an application of 21.3 kg ha⁻¹ of Mn. All cultivar, herbicide, and Mn treatments were evaluated in irrigated and non-irrigated environments with fertilizer N (PlusN treatment) or without fertilizer N (ZeroN treatment). When analyzed over all management practices (years, cultivars, herbicide, and Mn treatments), the PlusN treatment resulted in a significant decrease in protein concentration (2.7 and 1.9%), an increase in oil concentration (2.2 and 2.7%), and a decrease in the protein/oil ratio (4.7 and 4.6%) for the irrigated and non-irrigated environments, respectively. However, the overall protein and oil yield increased with the application of fertilizer N at planting (protein: 5.0% irrigated, 12.7% non-irrigated and oil: 9.9% irrigated and 18.9% non-irrigated). These increases were due to the increase in seed yield with the application of large amounts of fertilizer at planting. Additionally, a significant correlation (r = 0.45, P = 0.0001) was found between seed protein concentration and seed yield. No significant correlation was found between seed oil concentration and seed yield. The data demonstrate the inverse relationship between protein and oil and indicate that large amounts of N applied at planting do not change this relationship.     

Divergent selection at ultra-low plant density for seed protein and oil content within soybean cultivars

Soybean [Glycine max (L.) Merr.] seed is a major source of protein for animal feed and oil for human consumption. Selection within elite soybean cultivars for the improvement of agronomic and seed traits is assumed to be ineffective due to the belief that cultivars are highly homogeneous. Previously reported data suggest that latent variation among the single plant selections within a cultivar exists and that mechanisms that generate de novo variation may also be present. The main objective of this study was to perform divergent single-plant selection at ultra-low plant density and investigate the presence of genetic variation for seed protein and oil within three elite soybean cultivars. A secondary objective was to investigate the variation for fatty acid composition. In 1995, single plants from the three cultivars were grown in a honeycomb design using a plant-to-plant spacing of 0.9 m. A total of 333 plants from ‘Benning’, 392 plants from ‘Haskell’, and 371 plants from ‘Cook’ were evaluated. Divergent single-plant selection for protein and oil content was performed to select a total of 20 plants for high or low protein and 20 plants for high or low oil from each cultivar. The selected plants were further evaluated in replicated row-plot experiments for 3 years. Our results indicate that single-plant selection at low plant density was successful in discovering significant variation for seed protein and oil within each of the three soybean cultivars. For protein content, the magnitude of intra-cultivar variation between the highest- and lowest-protein lines averaged 19 g kg⁻¹ across the three cultivars and ranged from 13 to 24 g kg⁻¹. For oil composition, the magnitude of variation between the most divergent lines averaged 12 g kg⁻¹ across the three cultivars and ranged from 9 to 14 g kg⁻¹. Significant variation among the selected progeny lines was also discovered for specific fatty acid composition. The magnitude of intra-cultivar variation averaged from 6 to 29 g kg⁻¹ across the five fatty acids of soybean. The genetic variation discovered within the soybean cultivars is most likely due to latent variation and/or newly created variation. Our data provide evidence that single-plant selection at ultra-low plant density within elite cultivars can be effective in improving the seed composition of a soybean cultivar.     

Intraspecific responses in crop growth and yield of 20 soybean cultivars to enhanced ultraviolet-B radiation under field conditions

Field studies were conducted to determine the potential for intraspecific responses in crop growth and grain yield of 20 soybean cultivars to enhanced ultraviolet-B (UV-B, 280–315 nm) radiation. The supplemental UV-B radiation was 5.00 kJ m⁻², simulating a depletion of 20% stratospheric ozone at Kunming (25°N, 1950 m). Out of the 20 soybean cultivars tested, 17 and 15 showed significant change in plant height at 80 DAP (days after planting) and ripening stages, respectively. Sensitivity in plant height was greater at 80 DAP than at ripening. The plant height of 3 cultivars increased, and that of 17 cultivars decreased. Under UV-B radiation, LAI (leaf area index), biomass and grain yield decreased, respectively. The greatest percent decrease was 95.7, 93.9 and 92.8, respectively. RI (response index) was the sum of percent change in plant height at ripening, LAI, biomass and grain yield. The results showed that all 20 soybean cultivars had a negative RI, indicating inhibition by UV-B radiation on soybean growth. The RI of 6 tolerant cultivars was higher than −163.1 and 5 out of 6 originated from south China (low latitude). The RI of the most tolerant cultivars, Yunnan 97801, was −72.4. Meanwhile, the RI of 5 sensitive cultivars was lower than −256.9 and 4 out of the 5 originated from north China (high latitude). The RI of the most sensitive cultivar, Huanxianhuangdou, was −295.7. These UV-B tolerant cultivars identified in this study might be useful in breeding programs.     

Extraction of simmondsin and oil in one step from jojoba seeds

Approximately all simmondsin and oil can be easily removed in one step by repeated extraction with water at 90 °C from ground jojoba seeds. The optimum time and temperature of extraction were respectively 1.5 h and 90 °C. Quantitative analysis of simmondsin was made by HLPC method using adenosine as internal standard.     

Cardinal temperatures for germination and early growth of two Lesquerella species

Lesquerella (Lesquerella fendleri) is a potential alternative crop that is being studied for commercial oilseed production. Understanding the minimum temperatures for germination and seedling growth is important for determining potential areas for lesquerella production. The objectives of this study were to determine the cardinal temperatures for germination and seedling growth, and to screen ecotypes for germination and growth characteristics. A temperature gradient table arrangement was used to observe seed germination over a range of temperatures, and time to germination and shoot appearance. Times to 5 mm root length and 5 mm shoot length were also measured to assess cardinal temperatures for seedling survival and growth. Two different species were examined, L. fendleri and a species we refer to as ‘L. pallida aff.’ because it differed from typical L. pallida plants in chromosome number and in oil quality. We concluded that both germination and growth of L. pallida aff. occurred fastest at 22 °C, whereas L. fendleri germinated earlier at 18 °C, but grew faster at 22 °C. L. pallida aff. also had lower germination than L. fendleri over the range studied. Non-dormant seeds of improved lines of L. fendleri had better performance at temperatures above 22 °C than did unimproved accessions. Lines of L. fendleri selected for high oil content and salt tolerance had similar temperature requirements for germination except for improved line WCL-LO3, the current line being used in production. This line had optimal temperatures 6 °C higher for germination and growth than the other improved lines. Accessions of L. fendleri collected from elevations above 2000 m performed better at warmer temperatures, whereas those collected from elevations below 2000 m tended to perform better at cooler temperatures. Dormant seeds of L. fendleri germinated more quickly at low temperatures and had lower base (<3 °C) and optimal (22 °C) temperatures than non-dormant seeds (>7 °C and 28 °C, respectively). We speculate that this partial dormancy trait allows populations of L. fendleri to exploit a wider range of temperature conditions in the wild in order to thrive in extreme environments.     

Impact of redox agents on the physico-chemistry of wheat gluten proteins during hydrothermal treatment

The impact of the oxidants potassium bromate and potassium iodate and the reducing agent dithiothreitol (DTT) on the rheological behaviour of 20% (w/v) gluten-in-water suspensions during thermal treatment was monitored with the rapid visco analyser (RVA). The suspensions were subjected to a linear temperature increase from 40 to 95 °C in 14 min, a holding step of 40 min at 95 °C, a cooling step (7 min) with a linear temperature decrease to 50 °C, and a final holding step at 50 °C (13 min). Potassium iodate (1.18 and 1.77 μmol/g protein) and potassium bromate (1.52 and 15.2 μmol/g protein) decreased RVA viscosities in the holding step and increased sodium dodecyl sulphate (SDS) protein extractabilities suggesting a greater heat resistance and decreased gliadin–glutenin cross-linking. In contrast, in the presence of DTT (1.65 and 3.30 μmol/g protein) RVA viscosity increased at lower temperatures and lowered SDS extractabilities. It is postulated that low concentrations of reducing agent facilitate gliadin–glutenin cross-linking during heating while oxidants hinder gluten polymerization due to decreased levels of free sulphydryl groups and less flexibility of the glutenin chains.     

Paper from olive tree residues

An experimental design was performed to study the influence of process variables (135–175 °C for temperature, 60–120 min for pulping time and 15–25% for active alkali) on the properties of pulps (yield, Kappa index, viscosity, 1% NaOH solubles, alcohol–benzene extractives holocellulose, lignin and α-cellulose contents and brightness) and paper sheets (stretch index, burst index, and tear index) obtained from olive trimming residues. Obtaining pulps with acceptably high physical and chemical properties entails operating at a temperature of 175 °C for 90 min and 25% of active alkali. The paper sheets obtained from olive trimming residues pulps that were produced in different degrees of refining are characterised for their stretch index, burst index, and tear index. An increase in the different parameters for the paper sheet upon increasing the degree of refining is found. All pulps reached between 33 and 39 kN m/kg in the stretch index, between 1.5 and 2 kN/g for the burst index and 0.7–2.5 N m²/g for the tear index and not in excess of the refining degree (<45 °SR).     

Transesterification of epoxidized soybean oil to prepare epoxy methyl esters

Epoxidized methyl esters were prepared by the transesterification of epoxidized soybean oil (ESBO). The transesterification was complete in 10 min at 50 °C without loss of the epoxide function. Epoxidized methyl esters represent a renewable substrate that is readily converted into surfactants, fuel additives, and other industrial products. The implementation of this reaction will increase the availability of epoxidized methyl esters and promote the development of new biobased products.     

Kenaf seed storage duration on germination,emergence, and yield

Kenaf (Hibiscus cannabinus L.) is a potential alternative crop being developed for fiber production. Because planting area varies dramatically from year to year, seed supplies may greatly exceed use so that the excess seed must be stored for one to several years. The objectives of this study were to determine the effect of seed storage duration at 10 °C on germination, vigor, emergence, and yield. Replicated trials were established at Starkville, MS in 1999 and 2000 to evaluate field emergence and biomass yield of kenaf seed from five ‘Everglades 41’ (‘E41’) harvest year seed lots stored at 10 °C in ambient relative humidity for up to 4 years. Germination of these same seed lots under standard (20–30 °C) and cool (20 °C) temperatures, and seed vigor was evaluated over time. Field emergence was the same for the different seed storage durations up to 4 years, but was directly affected by drought conditions for each planted year. Biomass yields ranged from 12.39 to 14.57 Mg ha⁻¹ in 1999 and 16.82 to 18.47 Mg ha⁻¹ in 2000, but were not different between storage durations. Seed germination remained greater than 80% regardless of storage duration. Electrolyte leakage, based on conductivity, was 38–50% less with freshly harvested seed than seed stored for 4 years at 10 °C. However, neither the conductivity nor accelerated aging test were reliable predictors of field emergence. Kenaf seed stored up to 4 years at 10 °C retained germination rates acceptable for commercial use. Neither field emergence nor biomass yield was affected by seed storage duration.     

Differential accumulation of sulfur-rich and sulfur-poor wheat flour proteins is affected by temperature and mineral nutrition during grain development

Hard red spring wheat (Triticum aestivum cv Butte86) was grown under controlled environmental conditions and grain produced under 24/17 °C, 37/17 °C or 37/28 °C day/night regimens with or without post-anthesis N supplied as NPK. Flour proteins were analyzed and quantified by differential fractionation and RP-HPLC, and endosperm proteins were assessed by two-dimensional gel electrophoresis (2-DE). High temperature or NPK during grain fill increased protein percentage and altered the proportions of S-rich and S-poor proteins. Addition of NPK increased protein accumulation per grain under the 24/17 °C but not the 37/28 °C regimen. However, flour protein composition was similar for grain produced with NPK at 24/17 °C or 37/28 °C. 2-DE of gluten proteins during grain development revealed that NPK or high temperature increased the accumulation rate for S-poor proteins more than for S-rich proteins. Flour S content did not indicate S-deficiency, however, and addition of post-anthesis S had no effect on protein composition. Although, high-protein flour from grain produced under the 37/28 °C regimen with or without NPK had loaf volumes comparable to flour produced at 24/17 °C with NPK, mixing tolerance was decreased by the high temperature regimen.