•Carbohydrate effects on the properties of SBA through the Maillard reaction.•Sucrose and glucose act as a cross-linking agent during the curing process of SBA.•Sucrose and glucose could improve ...water resistance and bonding strength of SBA.•Polysaccharides could decrease water resistance and bonding strength of SBA.
The objective of this study was to determine the effects of carbohydrates on the water resistances and bonding strengths of soy-based adhesives (SBAs). Defatted soy flour (DSF), soy protein isolate (SPI), sucrose, and glucose were used to prepare SBAs, and the mechanisms of water resistance, hydrophilicity, and bonding strength (boiling-water test) were investigated. Fourier-transform infrared and X-ray photoelectron spectroscopies showed that the cross-linking and hydrophobicities of cured SBAs were enhanced by Maillard reactions between soy protein and sucrose and glucose. SBAs prepared with SPI and DSF had the lowest and highest water absorptions, respectively. The highest bonding strength was 0.73MPa, for a glucose content in the SBA of 71wt%. The lowest bonding strength was observed in a cured SBA prepared from DSF. A reduced carbohydrate content, or increased sucrose and glucose fractions in the carbohydrate, decreased the hydrophilicity and increased the bonding strength of the cured SBA.
Culturing cyanobacteria in a highly alkaline environment is a possible strategy for controlling contamination by other organisms. Synechocystis PCC 6803 cells were grown in continuous cultures to ...assess their growth performance at different pH values. Light conversion efficiency linearly decreased with the increase in pH and ranged between 12.5 % (PAR) at pH 7.5 (optimal) and decreased to 8.9 % at pH 11.0. Photosynthetic activity, assessed by measuring both chlorophyll fluorescence and photosynthesis rate, was not much affected going from pH 7.5 to 11.0, while productivity, growth yield, and biomass yield on light energy declined by 32, 28, and 26 % respectively at pH 11.0. Biochemical composition of the biomass did not change much within pH 7 and 10, while when grown at pH 11.0, carbohydrate content increased by 33 % while lipid content decreased by about the same amount. Protein content remained almost constant (average 65.8 % of dry weight). Cultures maintained at pH above 11.0 could grow free of contaminants (protozoa and other competing microalgae belonging to the species of Poterioochromonas).
In this study Fourier transform infrared micro-spectroscopy (FTIR) was used to determine lipid and carbohydrate content over time in the freshwater microalgae Chlamydomonas reinhardtii and ...Scenedesmus subspicatus grown in batch culture in limiting concentrations of nitrogen (N). Both algae exhibited restricted cell division and increased cell size following N-limitation. FTIR spectra of cells in N-limited media showed increasing lipid:amide I and carbohydrate:amide I ratios over time. The use of lipid- and starch-staining dyes confirmed that the observed ratio changes were due to increased lipid and carbohydrate synthesis. These results demonstrate rapid metabolic responses of C. reinhardtii and S. subspicatus to changing nutrient availability, and indicate the efficiency of FTIR as a reliable method for high-throughput determination of lipid induction.
The developmental changes of carbohydrates, organic acids, amino acids and phenolic compounds in ‘Honeycrisp’ apple flesh were investigated using GC–MS and HPLC. A total of 12 carbohydrates, 8 ...organic acids, 20 amino acids, and 18 phenolic compounds were identified and quantified. Each metabolite showed characteristic changes during fruit development, but in general, concentrations of most sugars and sugar alcohols either increased or remained unchanged whereas concentrations of most organic acids, amino acids and phenolic compounds decreased with fruit development, indicating that most sugars and sugar alcohols are synthesised and/or accumulate at a faster or similar rate relative to fruit growth whereas organic acids, amino acids and phenolics are synthesised and/or accumulate at a slower rate relative to fruit growth. On a whole fruit basis, the content of most metabolites increased with fruit development. In the flesh of mature ‘Honeycrisp’ apple, fructose and sucrose and sorbitol are the major sugars and sugar alcohol; malic acid is the major organic acid; aspartic acid, asparagine, glutamic acid, proline, threonine and γ-aminobutyric acid are the major amino acids; and procyanidin B1, procyanidin B2, chlorogenic acid, catechin and epicatechin are the major phenolic compounds, respectively.
Antioxidant and functional properties were evaluated for gelatin hydrolysates obtained from sole and squid skin gelatin by Alcalase, with a degree of hydrolysis of ∼35% and ∼50%, respectively. Both ...hydrolysates mainly consisted of peptides below 6.5
kDa, together with peptidic material from around 16 to 6.5
kDa. Moreover, the squid hydrolysate showed a peptide band of around 26
kDa. Antioxidant properties of both gelatins were highly increased by hydrolysis, especially ABTS and metal chelating abilities. The squid hydrolysate showed the highest antioxidant capacity by FRAP, ABTS and metal chelating assays in spite of the lower content in hydrophobic amino acids. Both gelatin hydrolysates had a good solubility (over 95%). The emulsifying activity index (EAI) decreased with increasing concentration. Conversely, the foam expansion increased with increasing concentration. However, both foam and emulsion stabilities were not apparently affected by the concentration of hydrolysate. In the case of the sole hydrolysate, which showed a lower degree Pro and Lys hydroxylation, foam stability was very poor, and 50% of foam expansion was lost after 5
min at all concentrations.
Enormous marine biodiversity offers an endless reservoir of chemicals for many applications. In this scenario, the extraction of seaweeds represents an interesting source of compounds displaying ...antimicrobial activity. In particular, among the different red algae,
plays an important role due to the presence of important bioactives in its composition. In spite of these features, an efficient culture system is still absent. In the present study, a novel algal culture method was developed and compared to another more common cultural practice, widely reported in literature. A higher efficiency of the new method, both for daily growth rate and biomass, was assessed. Furthermore, the growth inhibitory activity of five extracts, obtained using ethanol, methanol, acetone, chloroform or diethyl ether as a solvent, from the cultured
was tested against Gram-positive and Gram-negative pathogens. Algal extracts exhibited a considerable inhibitory activity against
strains, while a slight inhibition was observed against
. The different extracts showed significant differences in bacterial growth inhibition, with the highest activity that was recorded for the ethanol extract, followed by that of methanol. Based on the chemical characterization, these findings could be related to the antimicrobial activity played by the combination of total carbohydrates and polyphenols, which were determined at high levels in ethanol and methanol extracts, as well as by the highest number and levels of single polyphenols. Conversely, the lower growth inhibitory activities found in chloroform and diethyl ether extracts could be related to the isolation of minor lipid classes (e.g., neutral and medium polar lipids) composed by fatty acids, such as stearic, oleic and arachidonic acids, typically characterized by antimicrobial activity. In consideration of the results obtained, the present study has a double implication, involving both the field of cultural practices and the exploitation of natural sources for the isolation of antimicrobial agents useful both in pharmaceutical and food applications.
The long-term effects on growth performance, body composition, plasma metabolites, liver and intestine glucose and lipid metabolism were assessed in gilthead sea bream juveniles fed diets without ...carbohydrates (CH-) or carbohydrate-enriched (20 % gelatinised starch, CH+) combined with two lipid sources (fish oil; or vegetable oil (VO)). No differences in growth performance among treatments were observed. Carbohydrate intake was associated with increased hepatic transcripts of glucokinase but not of 6-phosphofructokinase. Expression of phosphoenolpyruvate carboxykinase was down-regulated by carbohydrate intake, whereas, unexpectedly, glucose 6-phosphatase was up-regulated. Lipogenic enzyme activities (glucose-6-phosphate dehydrogenase, malic enzyme, fatty acid synthase) and ∆6 fatty acyl desaturase (FADS2) transcripts were increased in liver of fish fed CH+ diets, supporting an enhanced potential for lipogenesis and long-chain PUFA (LC-PUFA) biosynthesis. Despite the lower hepatic cholesterol content in CH+ groups, no influence on the expression of genes related to cholesterol efflux (ATP-binding cassette G5) and biosynthesis (lanosterol 14 α-demethylase, cytochrome P450 51 cytochrome P450 51 (CYP51A1); 7-dehydrocholesterol reductase) was recorded at the hepatic level. At the intestinal level, however, induction of CYP51A1 transcripts by carbohydrate intake was recorded. Dietary VO led to decreased plasma phospholipid and cholesterol concentrations but not on the transcripts of proteins involved in phospholipid biosynthesis (glycerol-3-phosphate acyltransferase) and cholesterol metabolism at intestinal and hepatic levels. Hepatic and muscular fatty acid profiles reflected that of diets, despite the up-regulation of FADS2 transcripts. Overall, this study demonstrated that dietary carbohydrates mainly affected carbohydrate metabolism, lipogenesis and LC-PUFA biosynthesis, whereas effects of dietary lipid source were mostly related with tissue fatty acid composition, plasma phospholipid and cholesterol concentrations, and LC-PUFA biosynthesis regulation. Interactions between dietary macronutrients induced modifications in tissue lipid and glycogen content.
1. Studying the effects of climate or weather extremes such as drought and heat waves on biodiversity and ecosystem functions is one of the most important facets of climate change research. In ...particular, primary production is amounting to the common currency in field experiments world-wide. Rarely, however, are multiple ecosystem functions measured in a single study in order to address general patterns across different categories of responses and to analyse effects of climate extremes on various ecosystem functions. 2. We set up a long-term field experiment, where we applied recurrent severe drought events annually for five consecutive years to constructed grassland communities in central Europe. The 32 response parameters studied were closely related to ecosystem functions such as primary production, nutrient cycling, carbon fixation, water regulation and community stability. 3. Surprisingly, in the face of severe drought, above- and below-ground primary production of plants remained stable across all years of the drought manipulation. 4. Yet, severe drought significantly reduced below-ground performance of microbes in soil indicated by reduced soil respiration, microbial biomass and cellulose decomposition rates as well as mycorrhization rates. Furthermore, drought reduced leaf water potential, leaf gas exchange and leaf protein content, while increasing maximum uptake capacity, leaf carbon isotope signature and leaf carbohydrate content. With regard to community stability, drought induced complementary plant-plant interactions and shifts in flower phenology, and decreased invasibility of plant communities and primary consumer abundance. 5. Synthesis. Our results provide the first field-based experimental evidence that climate extremes initiate plant physiological processes, which may serve to regulate ecosystem productivity. A potential reason for different dynamics in various ecosystem services facing extreme climatic events may lie in the temporal hierarchy of patterns of fast versus slow response. Such data on multiple response parameters within climate change experiments foster the understanding of mechanisms of resilience, of synergisms or decoupling of biogeochemical processes, and of fundamental response dynamics to drought at the ecosystem level including potential tipping points and thresholds of regime shift. Future work is needed to elucidate the role of biodiversity and of biotic interactions in modulating ecosystem response to climate extremes.
Algogenic organic matter (AOM) can interfere with drinking water treatment processes and comprehensive characterisation of AOM will be informative with respect to treatability. This paper ...characterises the AOM originating from four algae species (
Chlorella vulgaris,
Microcystis aeruginosa,
Asterionella formosa and
Melosira sp.) using techniques including dissolved organic carbon (DOC), specific UV absorbance (SUVA), zeta potential, charge density, hydrophobicity, protein and carbohydrate content, molecular weight and fluorescence. All AOM was predominantly hydrophilic with a low SUVA. AOM had negative zeta potential values in the range pH 2–10. The stationary phase charge density of AOM from
C. vulgaris was greatest at 3.2
meq
g
−1 while that of
M. aeruginosa and
Melosira sp. was negligible. Lower charge density was related to higher hydrophobicity, while it was related in turn to increasing proteins >500
kDa:carbohydrate ratio. This demonstrates that AOM is of a very different character to natural organic matter (NOM).
This investigation was carried out in order to evaluate changes in biomass, carbohydrates, and calculated ethanol yield (CEY) from anthesis to 40 days after anthesis (DAA) of five sweet sorghum (
...Sorghum biocolor (L.) Moench) cultivars with a crop cycle length of 111–165 days in Beijing (39°56′N, 116°20′E). Aboveground dry weight (AGDW) and total soluble sugar yield (TSSY, 1.3–10.5
t
ha
−1) increased with time after anthesis and with crop cycle length. Cellulose and hemicellulose contents at anthesis varied between 205–277
g
kg
−1 and 187–232
g
kg
−1, respectively, and were significantly (
p
<
0.05) higher than either 20 DAA or 40 DAA. Cellulose and hemicellulose yields changed between 1.6 and 6.6
t
ha
−1 from anthesis to 40 DAA. The stems comprised major sinks of soluble sugar, with 79.4–94.6% of TSSY, and major sinks of insoluble sugar, with 55.9–75.9% of the total cellulose and hemicellulose yield. The hybrids exhibited higher TSSY, cellulose, hemicellulose and grain yield, and therefore also CEY than the inbred cultivars with a similar crop cycle length. Total CEY from the carbohydrates increased with time after anthesis and with crop cycle length, ranging between 4867 and 13032
L
ha
−1 on 40 DAA during the two years. It is concluded that the effects of each factor of year, harvest time, and genotype on biomass, carbohydrates yield, and CEY are highly significant. The interaction of genotype with year (environment) has significant effects on the total CEY. We recommend beginning the harvest of sweet sorghum upon the early maturity of the cultivars from around 20 DAA. This will result in a harvest period of around two months until grain maturity of the late cultivars for ethanol production in North China.
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