Search Results (6)

By focusing our attention on nitrogen components in plants, which are important for cultivation management in data-driven agriculture, we developed a simple, rapid, non-chemical and simultaneous quantification method for proteinic and nitrate nitrogen in a leaf model based on near-infrared (NIR) spectroscopic information obtained using a compact Fourier Transform NIR (FT-NIR) spectrometer. The NIR spectra of wet leaf models impregnated with a protein–nitric acid mixed solution and a dry leaf model obtained by drying filter paper were acquired. For spectral acquisition, a compact MEMS (Micro Electro Mechanical Systems) FT-NIR spectrometer equipped with a diffuse reflectance probe accessory was used. Partial least square regression analysis was performed using the spectral information of the extracted absorption bands based on the determination coefficients between the spectral absorption intensities and the contents of the two-dimensional spectral analysis between NIR and mid-infrared spectral information. Proteinic nitrogen content in the dry leaf model was well predicted using the MEMS FT-NIR spectroscopic method. Additionally, nitrate nitrogen in the dry leaf model was also determined by the provided method, but the necessity of adding the data for a wider range of nitric acid concentrations was experimentally indicated for the prediction of nitrate nitrogen content in the wet leaf model. Consequently, these results experimentally suggest the possibility of the application of the compact MEMS FT-NIR for obtaining the bioinformation of crops at agricultural on-sites. Full article

Arabinoxylans (AXs) extracted from distillers dried grains with solubles (DDGSs) were treated with amylase, amyloglucosidase, and protease, to evaluate their effect on the polysaccharide capability to form covalent electro-sprayed nanoparticles. Enzymatically treated arabinoxylans (AXPPs) presented a significant decrease in protein content and molecular weight (31 and 37%, respectively), while the ferulic acid content and the arabinose-to-xylose ratio (A/X) were not statistically modified. The Fourier transform infrared spectra of the AXPPs showed a diminution in the intensity of amide I and amide II bands concerning AXs. The AXPP gels (1% w/v) induced via laccase registered a slight increase in the dimers of ferulic acid cross-linking content (9%) and the G’ value (27%) about the AX gels. The electro-sprayed nanoparticles of AXs and AXPPs (NAXs and NAXPPs, respectively) revealed a spherical and regular morphology via transmission electron microscopy. The nanoparticle diameter was not different for the NAXs and NAXPPs, while the NAXPPs show a significant reduction in Z potential value compared to NAXs. Confocal laser microscopy observations were conducted, to analyze the protein content in the AX network, and a decrease in illuminated areas was observed in the AXPP gels and the NAXPPs. These results indicate that the enzymatical treatment of an AX improves the polysaccharide gelling capability, but does not influence the fabrication of electro-sprayed covalent nanoparticles. NAXs and NAXPPs could be attractive biomaterials for diverse pharmaceutical and biomedical applications. Full article

The pulsed electric field (PEF) was applied to improve the extraction yield and properties of rice bran proteins from two rice varieties (“Kum Chao Mor Chor 107” and “Kum Doi Saket”). As compared to the conventional alkaline extraction, PEF treatment at 2.3 kV for 25 min increased the protein extraction efficiency by 20.71–22.8% (p < 0.05). The molecular weight distribution detected by SDS-PAGE and amino acid profiles of extracted rice bran proteins was likely unchanged. The PEF treatment influenced changes in the secondary structures of rice bran proteins, especially from the β-turn to the β-sheet structure. Functional properties of rice bran protein including oil holding capacity and emulsifying properties were significantly improved by PEF treatments by about 20.29–22.64% and 3.3–12.0% (p < 0.05), respectively. Foaming ability and foam stability increased by 1.8- to 2.9-fold. Moreover, the in vitro digestibility of protein was also enhanced, which was consistent with the increment of DPPH and ABTS radical-scavenging activities of peptides generated under in vitro gastrointestinal digestion (37.84–40.45% and 28.46–37.86%, respectively). In conclusion, the PEF process could be a novel technique for assisting the extraction and modification of the protein’s digestibility and functional properties. Full article

A biologically active extract from the darkling beetle Ulomoides dermestoides was obtained using the electro-pulse plasma dynamic extraction method. The beetle water extract contained a complex of antioxidant substances such as antioxidant enzymes and nonprotein antioxidants, as well as a complex of heat shock antistress proteins. This determines the rather high antioxidant activity of the aqueous extract of the beetle, i.e., 1 mg of dry matter/mL of the extract has an equivalent antioxidant activity to 0.2 mM Trolox (a water-soluble analog of vitamin E). It was shown that the beetle extract can lead to a 25–30% increase in the average lifespan of nematode Caenorhabditiselegans, under normal conditions, and a 12–17% increase under conditions of oxidative stress (with paraquat), and significantly inhibits the fructosylation reaction of serum albumin. Therefore, the beetle aqueous extract shows promise as a biologically active complex exhibiting antioxidant activity. Full article

The nacreous layer of shells and pearls is composed of aragonite crystals arranged in an organic matrix. The organic matrix contains chitin and several proteins that regulate the formation of the nacreous layer. Owing to their strong interactions in the organic matrix, the current method for extraction of insoluble proteins from the pre-powdered nacreous layer involves heating to high temperatures in the presence of a detergent (e.g., sodium dodecyl sulfate, SDS) and reductant (e.g., dithiothreitol, DTT), which is likely to induce protein degradation. Therefore, we have developed an electroextraction method to isolate proteins from the organic matrix of a nacreous organic sheet, that was obtained following the decalcification of shells in their original shape. Our electroextraction method employs milder conditions without heating or detergent. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of the electro-extracted proteins (EEPs) under non-reduced and reduced conditions revealed that this method yielded a greater number of different proteins compared with the conventional extraction method and the isolated EEPs retained their disulfide bonds. Our method is able to easily extract insoluble proteins from the nacreous layer under mild conditions and will undoubtedly aid future analyses into the functions of the nacreous layer proteins. Full article

In fermentations of lignocelluloses, redox potentials (If not indicated otherwise, redox potentials in Volt are taken versus Normal Hydrogen Reference Electrodes (NHE).) E⁰ of laccases/plant peroxidases by 0.79/0.95 V enable oxidations of phenolic substrates and transformations of synthetic and substrate-derived compounds to radicals that mediate attacks on non-phenolic lignin (models) by 1.5 V. In consecutive one-electron abstractions, the redox mediator 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) is oxidized by electro- or wet-chemistry to the green cation radical (ABTS^•+, 0.68 V) and the red dication (ABTS²⁺, 1.09 V). The enzyme/ABTS couple generates the stable ABTS^•+ whose low E⁰ cannot explain the couple’s contemporary attack on non-phenolic lignins. This paradoxon indicates the non-confirmed production of the ligninolytic ABTS²⁺ by the enzymes. During incubations of live sapwood chips in ABTS/H₂O₂ to prove their constitutive peroxidase, the enzyme catalyzed the formation of the expected green-colored ABTS^•+ solution that gradually turned red. Its spectrophotometric absorbance peaks at λ = 515–573 nm resembled those of ABTS²⁺ at 518–520 nm. It is shown that portions of an ABTS^•+ preparation with inactivated enzyme are reduced to ABTS during their abiotic oxidation of low-MW extractives from lignocelluloses to redox mediating radicals. The radicals, in turn, apparently transform the remaining ABTS^•+ to red derivatives in the absence of functional oxidoreductases. Ultrafiltration and Liquid-Chromatography suggest the presence of a stable ABTS²⁺ compound absorbing at 515 nm, red protein/ABTS adducts, and further ABTS moieties. Therefore, ABTS mediated lignin degradations could result from chain reactions of ABTS^•+-activated lignocellulose extractives and fissured rather than complete ABTS²⁺ molecules. Full article