Impact Of Hydrothermal Treatments Research Articles

Impact of hydrothermal treatment on functional properties of pearl millet flour: process modelling and optimisation

Impact of hydrothermal treatment on functional properties of pearl millet flour: process modelling and optimisation

Understanding changes in holocellulose and lignin compounds in wooden structure of veneers: Molecular insights post hydrothermal treatment and aging

Veneers obtained via hydrothermal treatment serve to enhance the aesthetic appeal of furniture and other wooden surfaces. However, the impact of this treatment on the chemical composition of holocellulose and lignin, coupled with their resistance to ultraviolet (UV) irradiation, remains a relatively unexplored area requiring further investigation. In the experiment, wood samples of three distinct species underwent hydrothermal treatment followed by exposure to UV aging. Parameters including colour, contact angle, and acid-base properties were examined alongside their chemical alterations during these processes. These observed properties were then correlated with changes identified through FT-IR and Py-GC/MS analyses to uncover their molecular origins. Through these methods, the study offered insights into the chemical transformations driving the observed alterations. Findings revealed the considerable impact of hydrothermal treatment on these properties and their propensity for modification under UV radiation. In most test variations, hydrothermal treatment amplified tendencies toward colour changes, increased hydrophobicity, and basicity. Analysis of chemical changes suggested the degradation of polysaccharides due to hydrothermal treatment and lignin breakdown under UV irradiation. Understanding these molecular changes provides a foundation for mitigating the adverse effects of hydrothermal wood treatment.

Enhancement of CH4/N2 separation capacity of coal-based porous carbons via hydrothermal coupled KOH activation

The separation of CH4 and N2 is an important technology for the effective utilization of low-concentration CBM. To improve CH4/N2 separation properties of coal-based porous carbons, Shaanxi long-flame coal was hydrothermally treated followed by KOH activation for the preparation of porous carbons. The impact of hydrothermal treatment on the pore structure and CH4/N2 separation properties of porous carbons was investigated. The results show that hydrothermal decomposes the macromolecular structure of coal, which enlarges the pore size of the raw coal and facilitates the KOH penetrate deeper into the coal particles. Meanwhile, more release of methylene/methyl groups and in-stiu growth of carbon nanotubes develop the pore structure during the activation process of treated coal. The pore structure of porous carbons can be precisely controlled by adjusting the water-coal ratio in the hydrothermal process. Among them, C-TC1.25 shows a 22% increase in CH4 adsorption capacity over C-RC, which is mainly due to a significant increase in the micropore volume at 0.5–1.0 nm and generation of carbon nanotubes as gas transport channels. At 298 K and 101 kPa, C-TC1.25 exhibits a CH4 adsorption capacity reaching 1.72 mmol/g, which surpasses that of most known adsorbents, while the IAST selectivity is as high as 5.5. The breakthrough experiment confirms that the porous carbons effectively enable separation of CH4/N2 mixed gas. Kinetic studies show the CH4 adsorption process on C-TC1.25 conform to the pseudo-first-order model and exhibit surface-attached physical adsorption.

Impact of Hydrothermal Treatment on the Porous Structure and Adsorption Properties of Spherically Granulated Zirconium Silicate

Impact of Hydrothermal Treatment on the Porous Structure and Adsorption Properties of Spherically Granulated Zirconium Silicate

Impact of hydrothermal treatments on the functional, thermal, pasting, morphological and rheological properties of underutilized yam starches

Impact of hydrothermal treatments on the functional, thermal, pasting, morphological and rheological properties of underutilized yam starches

Impact of hydrothermal treatment on denaturation and aggregation of water-extractable quinoa (Chenopodium quinoa Willd.) protein

The extent of hydrothermally induced denaturation and aggregation of native quinoa protein depends on the process conditions. Proteins in quinoa extracts containing water-extractable albumins and dilute salt-extractable globulins aggregate when heated at pH 5.0 to 7.0. An I-optimal experimental design was used to investigate the impact of heating temperature (45–100 °C), time (1–15 min), pH (5.0–7.0) and protein content (25.0–100.0 mg/ml) on the total and covalent aggregation of aqueous quinoa extracts. These were evaluated by determining protein solubility losses in water and a sodium dodecyl sulfate containing medium, respectively, using size separation chromatography. Both protein solubility loss types were independent of the protein content during the treatment. While heating time only had an impact on the intensity of protein aggregation, temperature and pH also influenced the type of aggregates formed. Non-covalent protein aggregation was important when heating at temperatures not exceeding 70 °C and when the pH was close to the iso-electric point (pH 5.0). Covalent protein aggregation was maximal (ca. 25%) after heating 15 min at 100 °C and pH 7.0. Under these conditions, oligomeric protein structures (ca. 100–500 kDa) had been formed already after 1 min of heating which further had polymerized to larger ones (>500 kDa) after 5 min of heating. Mainly 7S and 11S globulins aggregated (predominantly by disulfide cross-links), while 2S albumins were not involved in covalent protein aggregation. Furthermore, intact 11S globulin monomers were most prone to covalently aggregate. The new insights allow tailoring quinoa protein aggregation by adjusting the hydrothermal treatment conditions.

Hydrothermal treatment of Tartary buckwheat grain hinders the transformation of rutin to quercetin

The impact of hydrothermal treatment on extractability of flavonoids from starchy matrix was investigated. Tartary buckwheat grain was hydrothermally treated (HT) and milled to yield HT flour. In not hydrothermally treated (NHT) Tartary buckwheat flour, most of extractable rutin (8 mg of rutin per g DM (dry matter)) was extracted during the first 20 min of extraction. In contrast, in HT Tartary buckwheat flour only 4 mg of rutin per g DM was extracted in 20 min, and 6 mg and 7 mg of rutin per g DM within 2 and 8 h, respectively. This indicates that, during the hydrothermal treatment, rutin becomes embedded in the flour matrix, becoming less readily extractable. Slowly extracted rutin was protected from transformation to quercetin during dough and bread making. Thus, from an initial 7 mg of extractable rutin per g DM in HT buckwheat flour, the resulting Tartary buckwheat bread contained 2 mg of rutin per g DM, and 6 mg of quercetin per g DM appeared. No other Tartary bread making technology which would be able to conserve such an amount of rutin from flour through the process to the final bread product is known to our knowledge.

Effect of Heat-Moisture Treatment on Resistant Starch Content as well as Heat and Shear Stability of Pearl Millet Starch

The impact of hydrothermal treatment on functional, rheological, thermal and morphological properties of pearl millet starch was investigated. Starch was modified by heat-moisture treatment (HMT) at 110 °C for 4 h at varying moisture content, i.e. 20 % (HMT-20), 25 % (HMT-25) and 30 % (HMT-30). Resistant starch (RS) content increased significantly (p < 0.05) due to HMT with maximum (6.14 %) for HMT-30. Dextrose equivalent (DE) value also increased due to HMT and ranged between 3.97 and 7.35 %. Solubility of the starch decreased, whereas swelling power and oil absorption capacity increased due to HMT. The pasting temperature increased while peak, breakdown, setback and final viscosity decreased after HMT. The G′ (storage modulus) of starch paste (5 %) from treated samples was lower as compared to native (33.5 Pa). The gelatinization temperature (Tp) increased significantly (p < 0.05) due to HMT. Pearl millet starch granules were mainly round/oval, irregular and polygonal shape with 3–12 µm size. HMT at higher moisture level (30 %) caused cavity on starch granules. This study indicated that HMT increased RS content. The gels of modified starches were softer, having higher self-levelling properties (G′–G″).

Hydrothermal Modifications of Granular Starch, with Retention of the Granular Structure: A Review

Annealing and heat−moisture treatment are two hydrothermal treatments that modify the physicochemical properties of starch, without destroying granular structure. They involve incubation of starch granules in excess water/intermediate water content (annealing) or at low moisture levels (heat−moisture treatment) during a certain period of time, at a temperature above the glass transition temperaturr but below the gelatinization temperature. The impact of hydrothermal treatments on starch physicochemical properties is extensively discussed. Such physicochemical properties include granule morphology and crystallinity, double-helix content, amount and appearance of amylose−lipid complexes, gelatinization and pasting, swelling power and solubility, gel properties, and susceptibilities to acid and enzymic hydrolysis. Finally, the major differences between the effects of annealing and heat−moisture treatment are pointed out and an overview is given of possible explanations for the observed effects of hydrothermal treatments. Keywords: Starch; hydrothermal modification; annealing; heat−moisture treatment