This research examines the growth of Chlorella sp. microalgae under nutrient limitation (10–200 mg NaNO3 L−1 and 10–70 mg K2HPO4 L−1) and different light intensities (60–450 μmol photons m−2 s−1) for ...achieving maximum carbohydrate content and biomass productivity using Response Surface Methodology (RSM) technique. According to the results, nutrition limitation had considerable effect on carbohydrate accumulation especially phosphorus concentrations; as in constant light intensities, maximum carbohydrate content was obtained in minimum concentration of K2HPO4. Under favorable circumstances; i.e. K2HPO4 = 10 mg L−1, NaNO3 = 105 mg L−1, and light intensity = 255 μmol photons m−2 s−1 the highest carbohydrate content by 60.9% was achieved. Moreover, Supercritical Water Gasification (SCWG) of carbohydrate enriched microalgal biomass is able to produce much more hydrogen gas in comparison to the basic microalgal biomass. In addition, a 1.85 times increase in amount of produced gas is appeared as a result of a change in biochemical composition of the microalgal biomass.
•Nutrient limitation is an effective strategy for increasing carbohydrate accumulation.•Higher light intensity and nutrient concentrations leads to higher biomass productivity.•Under optimized condition, the maximum carbohydrate productivity of 128 mg L−1d−1 was achieved.•Application of enriched carbohydrate microalgal biomass in SCWG caused up to 4.63 times increase in amount of hydrogen production.
This review article provides information on the nutritional and functional constituents of dates (Phoenix dactylifera L.) and their seeds from over 80 references. Date flesh is found to be low in fat ...and protein but rich in sugars, mainly fructose and glucose. It is a high source of energy, as 100 g of flesh can provide an average of 314 kcal. Ten minerals were reported, the major being selenium, copper, potassium, and magnesium. The consumption of 100 g of dates can provide over 15% of the recommended daily allowance from these minerals. Vitamins B-complex and C are the major vitamins in dates. High in dietary fiber (8.0 g/100 g), insoluble dietary fiber was the major fraction of dietary fiber in dates. Dates are a good source of antioxidants, mainly carotenoids and phenolics. Date seeds contain higher protein (5.1 g/100 g) and fat (9.0 g/100 g) as compared to the flesh. It is also high in dietary fiber (73.1 g/100 g), phenolics (3942 mg/100 g) and antioxidants (80400 μ mol/100 g). This detailed information on nutritional and health promoting components of dates and their seeds will enhance our knowledge and appreciation for the use of dates in our daily diet and their seeds as a functional food ingredient.
Supplementary lighting is frequently applied in the winter season for crop production in greenhouses. The effect of supplementary lighting on plant growth depends on the balance between assimilate ...production in source leaves and the overall capacity of the plants to use assimilates. This study aims at quantifying the source-sink balance and carbohydrate content of three tomato cultivars differing in fruit size, and to investigate to what extent the source/sink ratio correlates with the potential fruit size. Cultivars Komeet (large size), Capricia (medium size), and Sunstream (small size, cherry tomato) were grown from 16 August to 21 November, at similar crop management as in commercial practice. Supplementary lighting (High Pressure Sodium lamps, photosynthetic active radiation at 1 m below lamps was 162 μmol photons m(-2) s(-1); maximum 10 h per day depending on solar irradiance level) was applied from 19 September onward. Source strength was estimated from total plant growth rate using periodic destructive plant harvests in combination with the crop growth model TOMSIM. Sink strength was estimated from potential fruit growth rate which was determined from non-destructively measuring the fruit growth rate at non-limiting assimilate supply, growing only one fruit on each truss. Carbohydrate content in leaves and stems were periodically determined. During the early growth stage, 'Komeet' and 'Capricia' showed sink limitation and 'Sunstream' was close to sink limitation. During this stage reproductive organs had hardly formed or were still small and natural irradiance was high (early September) compared to winter months. Subsequently, during the fully fruiting stage all three cultivars were strongly source-limited as indicated by the low source/sink ratio (average source/sink ratio from 50 days after planting onward was 0.17, 0.22, and 0.33 for 'Komeet,' 'Capricia,' and 'Sunstream,' respectively). This was further confirmed by the fact that pruning half of the fruits hardly influenced net leaf photosynthesis rates. Carbohydrate content in leaves and stems increased linearly with the source/sink ratio. We conclude that during the early growth stage under high irradiance, tomato plants are sink-limited and that the level of sink limitation differs between cultivars but it is not correlated with their potential fruit size. During the fully fruiting stage tomato plants are source-limited and the extent of source limitation of a cultivar is positively correlated with its potential fruit size.
Little is known about postprandial release of serum ghrelin, glucagon, and glucagon-like peptide-1 (GLP-1) in relation with differing fasting insulin levels. We hypothesized that these hormones are ...affected by insulin resistance, and hence, we compared different postprandial responses of GLP-1, glucagon, and ghrelin in subjects with relatively high (RHI) or relatively low (RLI) fasting insulin levels. The trial was a randomized crossover study with 4 different meal conditions. Fourteen nonobese or obese, healthy, men and 14 women were randomly assigned to the order of supervised intake of a 750 kcal drink with the same protein contents but with 20 energy-percent (E%) or 55 E% from carbohydrates, and the remaining energy from fat. Participants were also randomized to consume the drinks as 1 large beverage or as five 150-kcal portions every 30 minutes. The 28 subjects were divided into 2 equally sized groups based on fasting insulin levels. Statistics were done with general linear mixed model. Fasting insulin levels were 3-fold higher in the group with RHI compared with the RLI group (RHI: 1004 ± 510 pg/mL, RLI: 324 ± 123 pg/mL, P < .0005). Serum GLP-1 was highest in the RHI group after both single meals and after 5 drinks and following high- and low-carbohydrate meals (both P ≤ .002), and this was the case also for glucagon levels (both P ≤ .018), whereas ghrelin levels did not differ between groups. Thus, subjects with RHI displayed both higher postprandial serum GLP-1 and glucagon than the participants with RLI, suggesting that glucagon could play a role in the advent of dysglycemia by insulin resistance.
Studies were conducted on properties of seeds and oil extracted from fully ripened
Phoenix canariensis date seeds. The percentage composition of the
P. canariensis seeds found is: ash 1.18%, oil ...10.36%, protein content 5.67%, total carbohydrate 72.59% and moisture 10.20%. The major nutrients (mg/100
g of oil) determined were: potassium (255.43), magnesium (62.78), calcium (48.56) and phosphorus (41.33). The physicochemical properties of the oil observed include: the saponification number 191.28; the iodine number 76.66, the p-anisidine value 3.67; the peroxide value 3.62
meq/kg; the unsaponifiable matter content 1.79%, the free fatty acids content 0.59%; the carotenoid content 5.51
mg/100
g; the chlorophyll content 0.10
mg/100
g and the refractive index 1.45. The main fatty acids of oil were oleic (50.10%), linoleic (19.23%), lauric (10.24%). palmitic (9.83%) and stearic (7.51%). The main triacylglycerols found in
P. canariensis seed oil were: LaMM
+
LaLaP (18.9%), LaMP
+
MMM (15.31%) and LaOO
+
PLL
+
MPL (12.86%). The DSC melting curves revealed that: melting point
=
3.71
°C and melting enthalpy
=
62.08
J/g. The sterol marker, β-sitosterol, accounted for 76.06% of the total sterols content in the seed oil followed by campesterol (8.89%) and Δ
5avenesterol (8.79%). α-Tocotrienol was the major tocol (66%) with the rest being γ-tocotrienol and γ-tocopherol.
Background: The domestication of Asian rice (Oryza sativa) was a complex process punctuated by episodes of introgressive hybridization among and between subpopulations. Deep genetic divergence ...between the two main varietal groups (Indica and Japonica) suggests domestication from at least two distinct wild populations. However, genetic uniformity surrounding key domestication genes across divergent subpopulations suggests cultural exchange of genetic material among ancient farmers. Methodology/Principal Findings: In this study, we utilize a novel 1,536 SNP panel genotyped across 395 diverse accessions of O. sativa to study genome-wide patterns of polymorphism, to characterize population structure, and to infer the introgression history of domesticated Asian rice. Our population structure analyses support the existence of five major subpopulations (indica, aus, tropical japonica, temperate japonica and GroupV) consistent with previous analyses. Our introgression analysis shows that most accessions exhibit some degree of admixture, with many individuals within a population sharing the same introgressed segment due to artificial selection. Admixture mapping and association analysis of amylose content and grain length illustrate the potential for dissecting the genetic basis of complex traits in domesticated plant populations. Conclusions/Significance: Genes in these regions control a myriad of traits including plant stature, blast resistance, and amylose content. These analyses highlight the power of population genomics in agricultural systems to identify functionally important regions of the genome and to decipher the role of human-directed breeding in refashioning the genomes of a domesticated species.
Milled rice from 11 varieties, with amylose levels from 1.2 to 35.6% dry base, were collected to study the impacts of amylose content on starch retrogradation and textural properties of cooked rice ...during storage. The relationship between amylose content and different properties was determined using Pearson correlation. Starch retrogradation enthalpy (Δ
H
r) of cooked rice was determined by differential scanning calorimetry. Δ
H
r values were found to be positively correlated with amylose content (0.603
≤
r
≤
0.822,
P
<
0.01) during storage. Textural properties were determined by a Texture Analyser. The hardness of cooked rice showed a positive correlation with amylose content (0.706
≤
r
≤
0.866,
P
<
0.01) and a positive correlation with Δ
H
r of cooked rice (
r
=
0.650,
P
<
0.01) during storage. The adhesiveness showed a negative correlation with amylose content (−0.929
≤
r
≤
−0.678,
P
<
0.01) and a negative correlation with Δ
H
r of cooked rice (
r
=
−0.833,
P
<
0.01) during storage. Hardness showed a negative correlation with adhesiveness (
r
=
−0.820,
P
<
0.01). These results indicated that amylose content has significant effects on starch retrogradation and textural properties of cooked rice. The cooked rice with high amylose content is easy to retrograde, the cooked rice with low amylose content retrograded slowly. Sarch retrogradation contributes to the changes of textural properties of cooked rice during storage.
Starch is a nutritionally important carbohydrate in feeds that is increasingly measured and used for formulation of animal diets. Discontinued production of the enzyme Rhozyme-S required for AOAC ...Method 920.40 invalidated this method for starch in animal feeds. The objective of this study was to compare methods for the determination of starch as potential candidates as a replacement method and for an AOAC collaborative study. Many starch methods are available, but they vary in accuracy, replicability, and ease of use. After assays were evaluated that differed in gelatinization method, number of reagents, and sample handling, and after assays with known methodological defects were excluded, 3 enzymatic-colorimetric assays were selected for comparison. The assays all used 2-stage, heat-stable, α-amylase and amyloglucosidase hydrolyses, but they differed in the gelatinization solution (heating in water, 3-(N-morpholino) propanesulfonic acid buffer, or acetate buffer). The measured values included both starch and maltooligosaccharides. The acetate buffer-only method was performed in sealable vessels with dilution by weight; it gave greater starch values (2-6 percentage units of sample dry matter) in the analysis of feed/food substrates than did the other methods. This method is a viable candidate for a collaborative study.
Barley hull, a lignocellulosic biomass, was pretreated using aqueous ammonia, to be converted into ethanol. Barley hull was soaked in 15 and 30 wt.% aqueous ammonia at 30, 60, and 75
°C for between ...12
h and 11 weeks. This pretreatment method has been known as “soaking in aqueous ammonia” (SAA). Among the tested conditions, the best pretreatment conditions observed were 75
°C, 48
h, 15
wt.% aqueous ammonia and 1:12 of solid:liquid ratio resulting in saccharification yields of 83% for glucan and 63% for xylan with 15 FPU/g-glucan enzyme loading. Pretreatment using 15
wt.% ammonia for 24–72
h at 75
°C removed 50–66% of the original lignin from the solids while it retained 65–76% of the xylan without any glucan loss.
Addition of xylanase along with cellulase resulted in synergetic effect on ethanol production in SSCF (simultaneous saccharification and co-fermentation) using SAA-treated barley hull and recombinant
E. coli (KO11). With 3% w/v glucan loading and 4
mL of xylanase enzyme loadings, the SSCF of the SAA treated barley hull resulted 24.1
g/L ethanol concentration at 15 FPU cellulase/g-glucan loading, which corresponds to 89.4% of the maximum theoretical yield based on glucan and xylan.
SEM results indicated that SAA treatment increased surface area and the pore size. It is postulated that these physical changes enhance the enzymatic digestibility in the SAA treated barley hull.
•The levels of SOC in 0–20cm of agricultural soils were 16–44% lower than natural.•Both methods of calculating carbon Stock showed similar results.•CHt and POCf detected greater differences between ...GAP and PAP.•POCc and CHs had the biggest losses from agricultural land use.
Soil organic matter (SOM) or carbon (SOC) is the most important component of the soil and it is composed of fractions with different lability. Particulate organic carbon (POC) and carbohydrates (CH), among others, are the most sensitive to changes in crops and soil management practices. The purpose of this study was to analyze different soil parameters aimed for the evaluation of management practices effects under widely different soil and climatic conditions. Soils were located along a West–East transect in the most productive region of the Argentinean pampas: West Bengolea and Monte Buey (Córdoba), Pergamino (Buenos Aires) and Viale (Entre Rios) East. Three treatments were defined according to land use: “Good agricultural practices” (GAP): sustainable agricultural management under no-till; “Poor agricultural practices” (PAP): non-sustainable agricultural management under no-till; “Natural environment” (NE): rangelands long as reference situation. Samples were taken at 0–10 and 10–20cm depths. SOC was determined in different particle size fractions: 105–2000μm (coarse particulate organic carbon, POCc), 53–105μm (fine particulate organic carbon, POCf), and 53μm (mineral-associated organic carbon, MOC). Total (CHt) and soluble (CHs) carbohydrate contents were also determined. The SOC level in NE was decreasing from the East (27.3gkg−1 in Viale) to the West (13.3gkg−1 in Bengolea), following the rainfall and texture gradient among sites. The POCc/SOC and POCc+POCf/SOC ratios in the NE showed differences among sites, suggesting different dynamic depending on the environmental characteristics at the different locations. The SOC levels in the upper layer of agricultural soils were 16–44% lower than natural ones. Carbon stocks were estimated for an equivalent mass of soil (950 and 2350Mgha−1) in order to consider differences in bulk densities among different treatments. Mean values were significantly different (p<0.001) for the different management practices: NE (26.6Mgha−1)>GAP (20.1Mgha−1)>PAP (16.3Mgha−1). In general, labile organic fractions showed differential sensitivity. Fractions with an intermediate dynamic, as POCf (53–100μm) and CHt, seem to be better indicators to detect the short- and medium-term management effects than more dynamic fractions.
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