Influence of Phosphorylation and Acetylation on Structural, Physicochemical and Functional Properties of Chestnut Starch

Chestnut is popular worldwide for its unique flavor, high eating quality and nutrition. Here, we evaluated the influence of phosphorylation and acetylation on the structural, physicochemical and functional properties of chestnut starch. Scanning electron micrographs showed the agglomeration of starch granules and the appearance of numerous dents on the starch granule surface under phosphorylation and acetylation. X-ray diffractograms confirmed that the modification treatments did not affect the C-type crystal pattern, but reduced the relative crystallinity of the chestnut starch, particularly phosphorylation. Moreover, modification improved the paste transparency of the starch. Differential scanning calorimeter analysis revealed that the gelatinization temperature and enthalpy of the starch decreased with the increasing substitution degree, particularly in phosphorylated starch. The Rapid Visco Analyser analysis demonstrated that phosphorylation could greatly improve the pasting properties of chestnut starch. In addition, phosphorylated and acetylated starch had a smaller amount of slowly digested starch and a larger amount of resistant starch relative to native chestnut starch. In conclusion, the functional and physicochemical properties of chestnut starch can be significantly improved through phosphorylation and acetylation, demonstrating its great application potential as a food additive.

Thermal Gelation for Synthesis of Surface-Modified Silica Aerogel Powders

A spherical silica aerogel powder with hydrophobic surfaces displaying a water contact angle of 147° was synthesized from a water glass-in-hexane emulsion through ambient pressure drying. Water glass droplets containing acetic acid and ethyl alcohol were stabilized in n-hexane with a surfactant. Gelation was performed by heating the droplets, followed by solvent exchange and surface modification using a hexamethyldisilazane (HMDS)/n-hexane solution. The pH of the silicic acid solution was crucial in obtaining a highly porous silica aerogel powder with a spherical morphology. The thermal conductivity, tapped density, pore volume, and BET surface area of the silica aerogel powder were 22.4 mW·m−1K−1, 0.07 g·cm−3, 4.64 cm3·g−1, and 989 m2·g−1, respectively. Fourier transform infrared (FT–IR) spectroscopy analysis showed that the silica granule surface was modified by Si-CH3 groups, producing a hydrophobic aerogel.

Coalescence and directed anisotropic growth of starch granule initials in subdomains of Arabidopsis thaliana chloroplasts

Living cells orchestrate enzyme activities to produce myriads of biopolymers but cell-biological understanding of such processes is scarce. Starch, a plant biopolymer forming discrete, semi-crystalline granules within plastids, plays a central role in glucose storage, which is fundamental to life. Combining complementary imaging techniques and Arabidopsis genetics we reveal that, in chloroplasts, multiple starch granules initiate in stromal pockets between thylakoid membranes. These initials coalesce, then grow anisotropically to form lenticular granules. The major starch polymer, amylopectin, is synthesized at the granule surface, while the minor amylose component is deposited internally. The non-enzymatic domain of STARCH SYNTHASE 4, which controls the protein’s localization, is required for anisotropic growth. These results present us with a conceptual framework for understanding the biosynthesis of this key nutrient.

Phosphorus retention by granulated apatite: assessing maximum retention capacity, kinetics and retention processes

Natural apatites have previously shown a great capacity for phosphate retention from wastewater. However, its fine particle size distribution may lead to a premature clogging of the filter. Accordingly, a granulated apatite product was developed and manufactured in order to control the particle size distribution of the media. Experiments were conducted on laboratory columns to assess their phosphorus retention capacity, to identify the processes involved in phosphorus retention and to evaluate their kinetic rates. The results showed phosphorus retention capacities of 10.5 and 12.4 g PO4-P·kg−1 and kinetic rate coefficients in the range of 0.63 and 0.23 h−1 involving lower values than those found for natural apatites in previous studies. Scanning Electron Microscopy images showed that apatite particles in the granules were embedded in the binder and were not readily accessible to act as seeds for calcium phosphate precipitation. The retention processes differ depending on the supersaturation of the solution with respect to calcium phosphate phases: at low calcium concentrations (69.8 ± 3.9 mg·L−1), hydroxyapatite precipitates fill up the porosity of the binder up to a depth of 100–300 μm from the granule surface; at higher calcium concentrations (112.7 ± 7.4 mg·L−1) precipitation occurs at the granule surface, forming successive layers of hydroxyapatite and carbonated calcium phosphates.

Extraction and quality evaluation of exosomes from joint effusion

Objective: The aim of this study was to compare the quality and efficiency of exosomes extracted from knee joint effusion by different methods, laying a foundation for further research on exosomes from knee joint effusion. Methods:To separate and extract joint exosomes by 8% polyethylene glycol (PEG) precipitation method, ultracentrifugation method (UC) and ultrafiltration with exclusion chromatography (SECF). Transmission electron microscopy (TEM) and nanoparticle tracing technology (NTA) were used to detect particle morphology and particle size, and Western Blot (WB) was used to detect marker proteins of granule surface (CD9, CD63, Flotillin-1 and calnexin).Results: Three methods separated vesicle-like round particles from joint effusion successfully. The results of TEM show that the particles obtained by the three extraction methods are round or oval vesicles, the plasma membrane is intact, the size is different, and the diameter is distributed between 30 and 150 nm. Compared with SECF group, PEG group had more background particle impurities. and the broken vesicle fragments can be seen in the UC group; The results of NTA show that the main peaks of the three groups of particles are between 100-120nm, and the particle concentration is greater than 1×1010/ml; The results of WB show that the protein expressions of CD9, CD63 and Flotillin-1 in the suspension extracted by the three methods were higher, the expression of calnexin protein in the PEG group was higher than the UC group and SECF group.Conclusion: The three extraction methods can extract the exosomes of joint effusion successfully. The quality of exosomes obtained by the SECF method is relatively high, while the PEG precipitation method contains a small amount of impurity particles. UC method does not guarantee the integrity of exosomes. In summary, we recommend the SECF method to extract and isolate joint effusion exudates-derived exosomes when further studying the role of exosomes in the pathogenesis of knee osteoarthritis.

KARAKTERISTIK PATI BERPORI MIKRO DARI TAPIOKA HASIL PERLAKUAN AMILASE SEBAGAI AGEN PENJERAPAN MINYAK [The Characteristic of Microporous Tapioca Starch After Amylase Treatment For Oil Adsorbent Agent]

Microporous starch can be used as oil adsorbent agent. The microporous starch can be produced through partial hydrolysis at temperature below gelatinization point using amylase. On the other hand, the study of amylase produced from Indonesian sea microbe, especially Brevibacterium sp. was rarely studied. Therefore, this paper discusses the tapioca characteristic made from Brevibacterium sp. amylase (treatment A) and commercial amylase (treatment B) as oil adsorbent agent. The result showed that the yield from treatment A and B was 74.65% and 12.75% while the starch granule size was 14.60 μm and 12,59 μm. The adsorbent test showed adsorption level of oil palm were 91,08% and 142,14% while for olive oil were 94,70% and 133,17%, for treatment A and B, respectively. The morphological test showed the presence of pori on the granule surface for both treatments with FTIR assessment showed no significant change in chemical functional group for both treatments. The color analysis showed almost similar brightness level between two treatments. In the end, microporous starch of treatment A has prospect as oil adsorbent agent like the one from commercial amylase