Mitigating methane emissions and global warming potential while increasing rice yield using biochar derived from leftover rice straw in a tropical paddy soil.

The sustainable management of leftover rice straw through biochar production to mitigate CH4 emissions and enhance rice yield remains uncertain and undefined. Therefore, we evaluated the effects of using biochar derived from rice straw left on fields after harvest on greenhouse gas emissions, global warming potential (GWP), and rice yield in the paddy field. The experiment included three treatments: chemical fertilizer (CF), rice straw (RS, 10 t ha-1) + CF, and rice straw-derived biochar (BC, 3 t ha-1 based on the amount of product remaining after pyrolysis) + CF. Compared with CF, BC + CF significantly reduced cumulative CH4 and CO2 emissions, net GWP, and greenhouse gas emission intensity by 42.9%, 37.4%, 39.5%, and 67.8%, respectively. In contrast, RS + CF significantly increased cumulative CH4 emissions and net GWP by 119.3% and 13.8%, respectively. The reduced CH4 emissions were mainly caused by the addition of BC + CF, which did not increase the levels of dissolved organic carbon and microbial biomass carbon, consequently resulting in reduced archaeal abundance, unlike those observed in RS + CF. The BC + CF also enhanced soil total organic carbon content and rice grain yield. This study indicated that using biochar derived from leftover rice straw mitigates greenhouse gas emissions and improves rice productivity in tropical paddy soil.

[Hg Content Characteristics and Safe Planting Zoning of Paddy Soil and Rice in Guizhou Province].

Guizhou Province ranks first in terms of Hg reserves and production in the country, and rice is its largest grain crop. In order to study the characteristics and pollution causes of soil-rice Hg content at the provincial level in Guizhou and to carry out safe planting zoning, 1 564 pairs of soil-rice samples, 470 natural soil samples, and 203 individual paddy soil samples were collected to test their Hg content and basic physical and chemical properties of the soil. The results showed that:① Paddy soil was mainly neutral and acidic, the paddy soil ω (Hg) range was 0.005-93.06 mg·kg-1, and the geometric mean was 0.864 mg·kg-1. The Hg content of paddy soil in Guizhou Province was significantly higher than that in natural soil (0.16 mg·kg-1,P < 0.05). Compared with the filtered value and control value, the soil samples exceeded the standard by 63.25% and 14.71%, respectively. Among them, the soil Hg pollution in Danzhai County of Qiandongnan Prefecture, Wuchuan County of Zunyi City, Zhenfeng County of Qianxinan Prefecture, and Wanshan District of Tongren City was more prominent. ② Rice ω(Hg) ranged from 0.000 5 to 0.52 mg·kg-1, and the geometric mean was 0.010 mg·kg-1, the percentage of rice Hg content exceeding the standard was 25.87%, and the exceeding points were mainly distributed in Suiyang County of Zunyi City, Zhenfeng County of Qianxinan Prefecture, Xixiu District of Anshun City, Bijiang District of Tongren City, and other industrial and mining activity-intensive areas. ③ The majority of the study area was in the priority protection category (74.75%); the safe use category accounted for (24.62%); and the strictly controlled category (0.93%) was scattered in Danzhai County at the border between Qiannan Prefecture and Qiandongnan Prefecture, Zhenfeng County in Qianxinan Prefecture, and Wanshan District in Tongren. It is not recommended to plant rice, which can be used as feed for reproduction.

[Effects of Modified Distillers' Grains Biochar on Cadmium Forms in Purple Soil and Cadmium Uptake by Rice].

Biochar and modified biochar have been widely used as remediation materials in heavy metal-contaminated agricultural soils. In order to explore economical and effective materials for the remediation of cadmium (Cd)-contaminated acidic purple soil, distillers 'grains were converted into distillers' grains biochar (DGBC) and modified using nano-titanium dioxide (Nano-TiO2) to produce two types of modified DGBCs:TiO2/DGBC and Fe-TiO2/DGBC. A rice pot experiment was used to investigate the effects of different biochar types and application rates (1%, 3%, and 5%) on soil properties, nutrient content, Cd bioavailability, Cd forms, rice growth, and Cd accumulation. The results showed that:① DGBC application significantly increased soil pH, cation exchange capacity (CEC), and nutrient content, with TiO2/DGBC and Fe-TiO2/DGBC exhibiting better effects. ② DGBC and modified DGBCs transformed Cd from soluble to insoluble forms, increasing residual Cd by 1.22% to 18.46% compared to that in the control. Cd bioavailability in soil decreased significantly, with available cadmium being reduced by 11.81% to 23.67% for DGBC, 7.64% to 43.85% for TiO2/DGBC, and 19.75% to 55.82% for Fe-TiO2/DGBC. ③ DGBC and modified DGBCs increased rice grain yield, with the highest yields observed at a 3% application rate:30.60 g·pot-1 for DGBC, 37.85 g·pot-1 for TiO2/DGBC, and 39.10 g·pot-1 for Fe-TiO2/DGBC, representing 1.13, 1.40, and 1.44 times the control yield, respectively. Cd content in rice was significantly reduced, with grain Cd content ranging from 0.24 to 0.30 mg·kg-1 for DGBC, 0.16 to 0.26 mg·kg-1 for TiO2/DGBC, and 0.14 to 0.24 mg·kg-1 for Fe-TiO2/DGBC. Notably, Cd content in rice grains fell below the food safety limit of 0.2 mg·kg-1 (GB2762-2022) at 5% for TiO2/DGBC and 3% and 5% for Fe-TiO2/DGBC. In conclusion, Nano-TiO2 modified DGBC effectively reduced the bioavailability of soil Cd through its own adsorption and influence on soil Cd forms distribution, thus reducing the absorption of Cd by rice and simultaneously promoting rice growth and improving rice yield. It is a type of Cd-contaminated soil remediation material with a potential application prospect. The results can provide scientific basis for farmland restoration and agricultural safety production of Cd-contaminated acidic purple soil.

Determination of trace chelating carboxylic acids in rice by green extraction combined with liquid chromatography-mass spectrometry analysis and its application in the evaluation of old and new rice.

RATIONALE: Accurate identification of old rice samples from new ones benefits their market circulation and consumers. However, the current detection methods are still not satisfactory because of their insufficient accuracy or (and) time-consuming process. METHODS: Chelating carboxylic acids (CCAs) were selectively extracted from rice, by stirring with chelating resin and a dilute Na2CO3 solution. The green analytical chemistry guidelines for sample preparation were investigated by using the green chemistry calculator AGREE prep. The extractant was determined by liquid chromatography-mass spectrometry (LC/MS), and statistical analysis of the analytical data was carried out to evaluate the significance of the difference by ChiPlot. RESULTS: The limit of quantitation for the CCAs is in the range of 1 to 50 ng/mL, with a reasonable reproducibility. The CCAs in 23 rice samples were determined within a wide concentration range from 0.03 to 1174 µg/g. Intriguingly, the content of citric acid, malonic acid, α-ketoglutaric acid and cis-aconite acid in new rice was each found to be distinctively higher than that in old rice by several times. Even mixtures of old and new rice were found to show much difference in the concentration of citric acid and malic acid. CONCLUSION: A green analytical method has been developed for the simultaneous determination of CCAs by LC/MS analysis, and the identification of old rice samples from new ones was easily carried out according to their CCA content for the first time. The results indicated that the described method has powerful potential for the accurate identification of old rice samples from new ones.

Rhodopseudomonas palustris shapes bacterial community, reduces Cd bioavailability in Cd contaminated flooding paddy soil, and improves rice performance.

Photosynthetic bacteria (PSB) are suitable to live and remediate cadmium (Cd) in the slightly oxygenated or anaerobic flooding paddy field. However, there is currently limited study on the inhibition of Cd accumulation in rice by PSB, and the relevant mechanisms has yet to be elucidated. In the current study, we firstly used Rhodopseudomonas palustris SC06 (a typical PSB) as research target and combined physiology, biochemistry, microbiome and metabolome to evaluate the mechanisms of remeding Cd pollution in paddy field and inhibiting Cd accumulation in rice. Microbiome analysis results revealed that intensive inoculation with R. palustris SC06 successfully survived and multiplied in flooding paddy soil, and significantly increased the relatively abundance of anaerobic bacteria including Desulfobacterota, Anaerolineaceae, Geobacteraceae, and Gemmatimonadaceae by 46.40 %, 45.00 %, 50.12 %, and 21.30 %, respectively. Simultaneously, the structure of microbial community was regulated to maintain relative stability in the rhizosphere soil of rice under Cd stress. In turn, these bacteria communities reduced bioavailable Cd and enhanced residual Cd in soil, and induced the upregulation of sugar and organic acids in the rice roots, which further inhibited Cd uptake in rice seedlings, and dramatically improved the photosynthetic efficiency in the leaves and the activities of antioxidative enzymes in the roots. Finally, Cd content of the roots, stems, leaves, and grains significantly decreased by 38.14 %, 69.10 %, 83.40 %, and 37.24 % comparing with the control, respectively. This study provides a new strategy for the remediation of Cd-contaminated flooding paddy fields and the safe production of rice.

The properties of the rice resistant starch processing and its application in skimmed yogurt.

Extrusion is typically employed to prepare resistant starch (RS). However, the process is complicated. In this study, the effects of twin-screw extrusion on the crystallinity, thermal properties, and functional properties of starch formed in different extrusion zones were investigated. The effects of this process on the rheological properties and microstructure of RS-added skimmed yogurt were also studied. According to the results, the RS content increased from 7.40 % in the raw material to 33.79 % in the extrudate. The A-type crystal structure of the starch was not observed. The dissociation temperature of the extruded starch ranged from 87.76 °C to 100.94 °C. The glycemic index (GI) of skimmed yogurt fortified with 0.4 % RS was 48.7, and the viscosity was also improved. The microstructure exhibited a uniform network of the starch-protein structure. The findings may serve as a theoretical basis for the application of RS in the food industry.

Nano zero-valent iron and melatonin synergistically alters uptake and translocation of Cd and As in soil-rice system and mechanism in soil chemistry and microbiology.

Nanoscale zero-valent iron (Fe) is a promising nanomaterial for remediating heavy metal-contaminated soils. Melatonin (MT) is essential to alleviate environmental stress in plants. However, the conjunction effects of Fe and MT (FeMT) on rice Cd, As accumulation and the mechanism of soil chemical and microbial factors interaction are unclear. Here, a pot experiment was conducted to evaluated the effects of the FeMT for rice Cd, As accumulation and underlying mechanisms. The findings showed that FeMT significantly reduced grains Cd by 92%-87% and As by over 90%, whereas improving grains Fe by over 213%. Soil available-Cd and iron plaques-Cd (extracted by dithionite-citrate-bicarbonate solution, DCB-Cd) significantly regulated roots Cd, thus affected Cd transport to grains. Soil pH significantly affected soil As and DCB-As, which further influenced roots As uptake and the transport to shoots and grains. The interactions between the soil bacterial community and soil Fe, available Fe, and DCB-Fe together affected root Fe absorption and transportation in rice. FeMT significantly influenced rhizosphere soil bacterial α- and ß-diversity. Firmicutes as the dominant phylum exhibited a significant positive response to FeMT measure, and acted a key role in reducing soil Cd and As availability mainly by improving iron-manganese plaques. The increase of soil pH caused by FeMT was beneficial only for Actinobacteriota growth, which reduced Cd, As availability probably through complexation and adsorption. FeMT also showed greater potential in reducing human health and ecological risks by rice consumption and straw returning. These results showed the important role of both soil chemical and microbial factors in FeMT-mediated rice Cd, As reduction efficiency. This study opens a novel strategy for safe rice production and improvement of rice iron nutrition level in heavy-metals polluted soil, but also provides new insights into the intricate regulatory relationships among soil biochemistry, toxic elements, microorganism, and plants.

Optimization of emulsification conditions with rice bran concentrates for the preliminary formulation of potential vegan dressings and their characterization.

A fraction of rice bran (RB), generated during the brown rice polishing, is utilized to extract oil, resulting in defatted RB (DRB). The aim of this study was to optimize the emulsification conditions to enhance the value of this byproduct by formulating potential vegan dressings and characterizing them. Enzymatic hydrolysis of the starch present in DRB yields the DRB concentrate (DRBC). A central composite design was applied and the results were analyzed using response surface methodology to select optimal conditions for an oil-in-water emulsion formula. Two formulations were chosen: one corresponds to the optimal conditions, with 26.5% of oil and 73.5% of DRBC dispersion (eoptimal), and the other one with 21.7% of oil and 78.3% of dispersion (eED8). The eoptimal formulation exhibited significantly lower mean De Brouckere diameter (D4,3) value and higher viscosity when compared with eED8. For both emulsions, the particle size distribution and D4,3 remained unchanged during storage, whereas viscosity decreased, and backscattering (BS) increased. Initially, both emulsions exhibited solid viscoelastic behavior, which was partially lost during quiescent storage. The increase in BS was attributed to particle disaggregation, ultimately leading to the aforementioned change in rheological behavior. In conclusion, although the designed emulsions underwent microstructural changes, they were stable against gravitational separation. To improve stability during quiescent storage, it is suggested to incorporate a thickening agent. Hence, it is propose to procced with the development of a vegan dressing based on the eoptimal emulsion, as it exhibits superior physicochemical properties.

[Provincial-scale Soil As Migration and Transformation and Rice Safe Planting Zoning: A Case Study of Guizhou Province].

To explore the distribution characteristics of paddy soil and rice AS content, as well as the health risks of rice consumption, and to evaluate the safe planting ability of rice, 209 paddy soil samples and 1 567 groups of paddy soil-rice samples were collected, their As content and basic soil physical and chemical properties were determined, and the single-factor pollution index method was used to evaluate the pollution degree of the samples. The results showed that:① the soil of paddy fields in Guizhou Province was mainly neutral, and its fertilizer retention capacity and organic matter content were above the medium level, and the soil was relatively fertile. The range of ω(As) in paddy soil was 0.042-91.75 mg·kg-1, the geometric mean was 10.03 mg·kg-1, and the cumulative effect of paddy soil As was lower than that of natural soil As (P<0.05) by independent sample T. Compared with the screening value (0.2 mg·kg-1) of the Soil Pollution Risk Management and Control Standard for Agricultural Land (GB 15618-2018), the excess rate of soil samples was 15.37%. ② The ω (As) range of rice grain samples was 0.001-0.937 mg·kg-1, the geometric average value was 0.108 mg·kg-1, 10.21% of the rice grain samples exceeded the limit value of "Limit of Contaminants in Food (trial)" (GB 2762-2022), and the locations where the exceedances are mainly found are in the central and northern parts of Qiannan Prefecture, as well as around industrial and mining activity zones in the southern counties and districts of Zunyi. ③ As ingested through rice posed non-carcinogenic risk and carcinogenic risk for adults and children, and the impact on children was greater than that of adults. There is no strict control area for safe rice planting in Guizhou Province, and rice can be safely planted.

[Effect of Silica Fertilizer(Husk Ash) to Improve Soil Quality and Reduce Cd and As Accumulation in Rice].

A rice pot experiment was conducted to identify the effect of silica fertilizer prepared from husk ash on the soil bioavailability of cadmium (Cd) and arsenic (As), enzyme activities, microbial community structure, and heavy metal content in brown rice at different growth stages. The results showed that the application of 0.1%-1.0% silica fertilizer-husk ash increased the pH value of soil by 0.04-0.24 units and the content of soil available silicon by 44.2%-97.5%. It also decreased the content of available Cd and available As by 16.2%-21.4% and 16.0%-24.9%, respectively. With the increase in application amount, the soil enzyme activities increased at all growth stages, and the sucrase activity and the dehydrogenase activity significantly increased by 6.3%-145.7% and 6.7%-224.1%, respectively. The analysis of the soil microbial community composition structure at mature stages showed that the application of silica fertilizer-husk ash had no effect on microbial α-diversity, but it had a significant effect on microbial ß-diversity and then promoted microbial growth and maintained the stability of the community structure. With the increase in application amount, the contents of Cd in brown rice decreased by 29.3%-89.7%, and the contents of total As and inorganic As in brown rice decreased by 7.8%-42.3% and 17.2%-44.5%, respectively. Under the application of 0.5% and 1.0% silica fertilizer-husk ash, the Cd contents in brown rice were lower than 0.2 mg·kg-1, and the inorganic As contents in brown rice were lower than 0.35 mg·kg-1. In conclusion, the silica fertilizer-husk ash can improve soil quality and reduce the contents of Cd and As in brown rice, and it is eco-friendly and can be used to remedy the paddy soil contaminated with Cd and As.

Co-densification of rice straw and cow dung in different food-to-microorganism ratios for biogas production.

Agricultural residues such as rice straw (RS) are desirable raw materials for biogas generation. However, the recalcitrant nature of RS hinders biogas production, and its low bulk density increases storage space requirements, transportation needs, and overall costs. These challenges could be resolved by pretreatment and pelletization. In this study, various thermal pretreatments were performed, and the best conditions (temperature and time) were identified. Also, rice straw and cow dung pellets (RCP) at different food-to-microorganism (F/M) ratios (0.5-2.5) were prepared. Parameters such as bulk density, moisture absorption, and drop shatter tests were conducted to evaluate the physical properties. Finally, the biochemical methane potential (BMP) study of the best RCP with varying total solids (TS: 4-12%) content was investigated. The results indicate that hot air oven pretreatment (for 60 min at 120 °C) resulted in maximum solubilization. In physical characteristics, RCP with an F/M ratio of 2.5 pellets was ideal. The bulk density of RCP 2.5 was found to be around 25 times that of the raw. Also, the TS 8% yielded maximum biomethane (279 mL/g-VSconsumed) as compared to other TS contents. Overall, this study will propel the growth of bioenergy while simultaneously tackling the pressing issues related to RS management.

Feasibility of replacing waxy rice with waxy or sweet-waxy corn viewed from the structure and physicochemical properties of starches.

To explore the feasibility of substituting waxy rice with waxy or sweet-waxy corn, eight varieties of waxy and sweet-waxy corns were selected, including three self-cultivated varieties (Feng nuo 168, Feng nuo 211, and Feng nuo 10). Their starches were isolated and used as research objects, and commercially available waxy rice starch (CAWR) and waxy corn starch (CAWC) were used as controls. X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, rapid viscosity analyzer, and rotational rheometer were used to analyze their physicochemical and structural characteristics. The morphologies of all corn starch granules were generally oval or round, with significant differences in particle size distributions. All ten starches exhibited a typical A-type crystal structure; however, their relative crystallinity varied from 20.08% to 31.43%. Chain length distribution analysis showed that the A/B ratio of Jing cai tian nuo 18 and Feng nuo 168 was similar to that of CAWR. Peak viscosities of corn starches were higher than that of CAWR, except for Feng nuo 10, while their setback values were lower than that of CAWR. Except for Feng nuo 10, the paste transparency of corn starches was higher than that of CAWR (10.77%), especially for Jing cai tian nuo 18 (up to 24%). In summary, Jing cai tian nuo 18 and Feng nuo 168 are promising candidates to replace CAWR in developing various rice-based products.

Rice straw returning enhances cadmium activation by accelerating iron cycling thus hydroxyl radical production in paddy soils during drainage.

Straw returning is widely found elevating the bioavailability of cadmium (Cd) in paddy soils with unclear biogeochemical mechanisms. Here, a series of microcosm incubation experiments were conducted and spectroscopic and microscopic analyses were employed. The results showed that returning rice straw (RS) efficiently increased amorphous Fe and low crystalline Fe (II) to promote the production of hydroxyl radicals (OH) thus Cd availability in paddy soils during drainage. On the whole, RS increased OH and extractable Cd by 0.2-1.4 and 0.1-3.3 times, respectively. While the addition of RS effectively improved the oxidation rate of structural Fe (II) mineral (i.e., FeS) to enhance soil Cd activation (up to 38.5 %) induced by the increased OH (up to 69.2 %). Additionally, the existence of CO32- significantly increased the efficiency level on OH production and Cd activation, which was attributed to the improved reactivity of Fe (II) by CO32- in paddy soils. Conclusively, this study emphasizes risks of activating soil Cd induced by RS returning-derived OH, providing a new insight into evaluating the safety of straw recycling.

Iron-modified biochar inhibiting Cd uptake in rice by Cd co-deposition with Fe oxides in the rice rhizosphere.

Fe-enriched biochar has proven to be effective in reducing Cd uptake in rice plants by enhancing iron plaque formation. However, the effect of Fe on biochar, especially the biochar with high S content, for Cd immobilization in rice rhizosphere was not fully understood. To obtain eco-friendly Fe-loaded biochar at a low cost, garlic straw, bean straw, and rape straw were chosen as the feedstocks for Fe-enhanced biochar production by co-pyrolysis with Fe2O3. The resulting biochars and Fe-loaded biochars were GBC, BBC, BRE, GBC-Fe, BBC-Fe, and BRE-Fe, respectively. XRD and FTIR analyses showed that Fe was successfully loaded onto the biochar. The pristine and Fe-containing biochars were applied at rates of 0% (BC0) and 0.1% in pot experiments. Results suggested that BBC-Fe caused the highest reduction in Cd content of rice grain, and the reductions were 67.9% and 31.4%, compared with BC0 and BBC, respectively. Compared to BBC, BBC-Fe effectively reduced Cd uptake in rice roots by 47.5%. The exchangeable and acid-soluble fraction of Cd (F1-Cd) in soil with BBC-Fe treatment was 37.6% and 63.7% lower than that of BC0 and BBC, respectively. Compared to BC0, soil pH was increased by 0.53 units with BBC-Fe treatment. BBC-Fe significantly increased Fe oxides (free Fe oxides, amorphous Fe oxides, and complex Fe oxides) content in the soil as well. DGT study demonstrated that BBC-Fe could enhance the mobility of sulfate in the rhizosphere, which might be beneficial for Cd fixation in the rhizosphere. Moreover, BBC-Fe increased the relative abundance of Bacteroidota, Firmicutes, and Clostridia, which might be beneficial for Cd immobilization in the rhizosphere. This work highlights the synergistic effect of loaded Fe and biochar on Cd immobilization by enhancing Cd deposited with Fe oxides.

Mild steam treatment: Enhancing the rehydration performance of instant rice noodles by changing the physicochemical properties and gel structure of rice starch.

The "instant" quality of instant rice noodles is significantly affected by slow rehydration during cooking. This happens as a result of the native rice starch's low ability to gelatinize as well as the high shear and pressure utilized in industries during the widely used extrusion molding process. In order to address this issue, the rice flour was pretreated with mild steam (MS) technology. The results revealed that the rehydration qualities of the rice noodles that were extruded from the steam-treated flour significantly improved. There was a reduction of 25.5% in the rehydration time, from 443 to 330 s. The MS-treated rice starch's peak viscosity increased to 4503 from 4044 mPa/s. Decreases in gelatinization enthalpy (ΔH) and short-range ordering also suggest a reduction in difficulty in accomplishing starch gelatinization. Scanning electron microscopy studies showed particle aggregation increased as the treatment duration lasted longer. In conclusion, our findings indicate that we successfully addressed the issue of slow rehydration in instant rice noodles while presenting a novel approach for their manufacturing in the manufacturing sector.

Effects of foliar application of Zn combined with organic matters on Cd accumulation and its chemical forms in rice.

Rice consumption is a key Cd exposure pathway, which poses a health risk to humans. Reducing cadmium (Cd) concentrations in rice remains challenging. In this study, a pot experiment was conducted to examine the effects of foliar spray of Zn combined with organic matters (including Zn-lysine (Zn-Lys), Zn-fulvic acid (Zn-FA), Zn-amino acid (Zn-AA), and Zn combined with glutathione (Zn + GSH)) on Cd accumulation in rice grains. Compared with the control group, all treatment groups exhibited reduced Cd concentration in rice grains, while improving plant growth, and reducing Cd transport from other tissues to the grains. Zn-FA was found to be the most effective fertilizer, which considerably reduced Cd concentrations in grains from 0.77 ± 0.068 to 0.14 ± 0.021 mg/kg and yielded reductions of up to 81%, which is within the Chinese food maximum tolerable limit of 0.2 mg/kg. Furthermore, the analysis of the chemical forms of Cd of rice tissues indicated that the treatment groups had increased proportions of integrated with pectates and protein in the stems. Except for the group treated with Zn-Lys spray, the percentages of undissolved Cd phosphate in the leaves were increased in all treatment groups, which reduced Cd toxicity to rice plants. The foliar application of Zn combined with organic matters may be a promising strategy to decrease Cd concentration in rice grains cultivated in severely Cd-contaminated agricultural soil, particularly in the karst area in southwest China with limited available cultivable agricultural land.

Soil amendments alter cadmium distribution and bacterial community structure in paddy soils.

Soil amendments play a pivotal role in ensuring the safety of food production by inhibiting the transfer of heavy metal ions from soils to crops. Nevertheless, their impact on soil characteristics and the microbial community and their role in reducing cadmium (Cd) accumulation in rice remain unclear. In this study, pot experiments were conducted to investigate the effects of three soil amendments (mineral, organic, and microbial) on the distribution of Cd speciation, organic components, iron oxides, and microbial community structure. The application of soil amendments resulted in significant reductions in the soil available Cd content (16 %-51 %) and brown rice Cd content (16 %-78 %), facilitating the transformation of Cd from unstable forms (decreasing 10 %-20 %) to stable forms (increasing 77 %-150 %) in the soil. The mineral and organic amendments increased the soil cation exchange capacity (CEC) and plant-derived organic carbon (OC), respectively, leading to reduced Cd accumulation in brown rice, while the microbial amendment enhanced OC complexity and the abundances of Firmicutes and Bacteroidota, contributing to the decreased rice Cd uptake. The synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy indicated that soil amendments regulated soil Cd species by promoting iron oxides and OC coupling. Moreover, both organic and microbial amendments significantly reduced the diversity and richness of the bacterial communities and altered their compositions and structures, by increasing the relative abundances of Bacteroidota and Firmicutes and decreasing those of Acidobacteria, Actinobacteria, and Myxococcota. Soil microbiome analysis revealed that the increase of Firmicutes and Bacteroidota associated with Cd adsorption and sequestration contributed to the suppression of soil Cd reactivity. These findings offer valuable insights into the potential mechanisms by which soil amendments regulate the speciation and bioavailability of Cd, and improve the bacterial communities, thereby providing guidance for agricultural management practices.

Enhancing functional properties of rice starches through hydroxypropylation for development of reduced-fat white sauces.

Present study investigated the preparation of commonly used white sauce with 50 % less added fat by using 10 % hydroypropylated Irri and Basmati rice starches in the formulation. The sauces incorporated with hydroxypropylated starches exhibited significantly lower gelatinization temperature and time, while the change in maximum viscosity was insignificant. Significantly improved stability at ambient, refrigeration, and freezing temperatures of reduced-fat white sauces was observed whereas change in the taste was insignificant. Basmati hydroxypropylated starch containing white sauce significantly mimicked the sensory properties of full-fat sauces. The hydroxypropyl groups were found to be 1.06 % and 1.16 % for Basmati and Irri hydroxypropylated starches, respectively. These values fall below the specified limit set by the Food and Drug Administration for the food grade hydroxypropylated starches. Significant improvements in peak viscosity, swelling power, solubility, percent transmittance, and water retention capacity were observed after the chemical modification of both rice varieties.

Preparation of type 3 rice resistant starch using high-pressure homogenous coenzyme treatment and investigating its potential therapeutic effects on blood glucose and intestinal flora in db/db mice.

Resistant starch from rice was prepared using high-pressure homogenization and branched chain amylase treatment. The yield, starch external structure, thermal properties, and crystal structure of rice-resistant starch prepared in different ways were investigated. The results showed that the optimum homogenizing pressure was 90 MPa, the optimum digestion time was 4 h, the optimum concentration of branched-chain amylase was 50 U/g and the yield of resistant starch was 38.58 %. Scanning electron microscopy results showed a rougher surface and more complete debranching of the homogenized coenzyme rice-resistant starch granules. FT-IR and X-ray diffraction results showed that the homogenization treatment exhibited a spiral downward trend on rice starch relative crystallinity and a spiral upward trend on starch debranching and recrystallization. The 4-week dietary intervention in db/db type 2 diabetic mice showed that homogeneous coenzyme rice-resistant starch had a better glycemic modulating effect than normal debranched starch and had a tendency to interfere with the index of liver damage in T2DM mice. Additionally, homogeneous coenzyme rice-resistant starch proved more effective in improving intestinal flora disorders and enhancing the abundance of probiotics in T2DM mice.

Modulation of starch structure, swallowability and digestibility of 3D-printed diabetic-friendly food for the elderly by dry heating.

Elderly people often experience difficulty in swallowing and have impaired regulation of the nervous system. Furthermore, their blood glucose level can rise easily after eating. Therefore, functional foods that are easy to swallow and can maintain blood glucose at a lower level have been an important research topic in recent years. In this study, 3D printing was combined with dry heating to modify the starch in white quinoa and brown rice to develop whole grain foods with Osmanthus flavor that meet the dietary habits of the elderly. The samples were tested for printability, swallowing performance, and in vitro digestion. The results showed that after dry heating, all samples had shear-thinning properties and could pass through the extrusion nozzle of the printer smoothly. Both white quinoa and brown rice showed improved printability and self-support compared to the control. B45 (white quinoa, dry heating for 45 min) and C45 (brown rice, dry heating for 45 min) had significant elasticity and greater internal interaction strength during swallowing to resist disintegration of food particles during chewing. B45, C30, and C45, conformed to class 4 consistency and were characterized by easy swallowing of the diet. Further, dry heating resulted in greater resistance to enzymatic degradation of white quinoa and brown rice starch, with overall in vitro digestibility lower than the control.