Ultrasound-assisted preparation of octenyl succinic anhydride modified starch and its influence mechanism on the quality

The purpose of this study was to reveal the influence mechanism of preparing high quality modified starch by ultrasonic-assisted treatment. In this paper, ultrasonic modified starch and octenyl succinic anhydride (OSA) modified starch were prepared under ultrasonic conditions. The effect of ultrasound on the structure and properties of native starch were studied to see whether ultrasound could produce mechanochemical effect on starch granules. Then the mechanism of ultrasonic effect on the quality of OSA-modified starch was revealed by mechanochemical effect. The results showed that the morphology and crystalline regions of starch granules were destroyed after ultrasonic treatment, and the structure and properties of starch granules changed in different stages. These changes showed that ultrasonic treatment produced significant mechanochemical effect on starch granules. Thus the quality of OSA-modified starch prepared by ultrasonic-assisted treatment was improved significantly, and its influence mechanism was analyzed using the theory of mechanochemistry.

Ultrasound-Assisted Preparation, Characterization, and Antibacterial Activity of Montmorillonite Modified by ε-Polylysine Hydrochloride

In this study, two types of antibacterial montmorillonites (Mt) were prepared using a facile method. The Mt modified with ε-polylysine hydrochloride (ε-PL) was named PL-Mt, while the Mt dually modified with dioctadecyl dimethylammonium chloride (D1821) and ε-PL was named PL-OMt. The results of the X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) of the PL-Mt indicated that 30% ε-PL was the most suitable amount for intercalating the Mt. The particle size and distribution of the ε-PL in the solution demonstrated that the Mt d-value could not be further increased owing to the increasing ε-PL diameter. The result of the X-ray diffraction of PL-OMt displayed that ultrasonic treatment at 600 W facilitated ε-PL to intercalate into the OMt interlayer space. The PL-OMt prepared with ultrasonic treatment at 600 W exhibited antibacterial activity against Escherichia coli and Bacillus subtilis superior to that of the PL-OMt prepared with higher-power ultrasonic treatment. Thus, the addition of 30% ε-PL based on the dry Mt mass is the most suitable ratio for preparing PL-Mt, while ultrasonic treatment at 600 W is the most suitable for preparing PL-OMt. These findings may expand the application fields of ε-PL.

Effects of Preparation Method on the Physicochemical Properties of Cationic Nanocellulose and Starch Nanocomposites

Nanocellulose (NC) has attracted attention in recent years for the advantages offered by its unique characteristics. In this study, the effects of the preparation method on the properties of starch films were investigated by preparing NC from cationic-modified microcrystalline cellulose (MD-MCC) using three methods: Acid hydrolysis (AH), high-pressure homogenization (HH), and high-intensity ultrasonication (US). When MD-MCC was used as the starting material, the yield of NC dramatically increased compared to the NC yield obtained from unmodified MCC and the increased zeta potential improved its suspension stability in water. The NC prepared by the different methods had a range of particle sizes and exhibited needle-like structures with high aspect ratios. Fourier transform infrared (FTIR) spectra indicated that trimethyl quaternary ammonium salt groups were introduced to the cellulose backbone during etherification. AH-NC had a much lower maximum decomposition temperature (T_max) than HH-NC or US-NC. The starch/HH-NC film exhibited the best water vapor barrier properties because the HH-NC particles were well-dispersed in the starch matrix, as demonstrated by the surface morphology of the film. Our results suggest that cationic NC is a promising reinforcing agent for the development of starch-based biodegradable food-packaging materials.

Mechanochemical effect of ultrasound on sweet potato starch and its influence mechanism on the quality of octenyl succinic anhydride modified starch

The purpose of this study is to reveal the mechanism of preparing high quality modified starch by ultrasonic technology. In this paper, ultrasonic modified starch and octenyl succinic anhydride modified starch with low degree of substitution were prepared under ultrasonic conditions, using sweet potato starch as raw material. The effects of ultrasound on the structure and properties of native sweet potato starch were studied to see whether ultrasound could produce mechanochemical effect on starch. Then the mechanism of ultrasonic effect on quality of octenyl succinic anhydride modified starch was studied by mechanochemical effect. The results showed that after ultrasonic treatment for 1 min, the crystallinity decreased from 37.6 to 33.8% and reaction efficiency increased from 49.43 to 54.39%, while after ultrasonic treatments for 8 and 32-60 min had different changes. These changes showed that ultrasonic treatment produced significant mechanochemical effect on native sweet potato starch. Ultrasound significantly improved the quality of octenyl succinic anhydride modified starch, and its influence mechanism was revealed using the theory of mechanochemistry. This study provides a feasible method for the research of high quality modified starch and lays a theoretical foundation for expanding the application of ultrasound in various fields.

Cytotoxicity of Deoxynivalenol after Being Exposed to Gaseous Ozone

In this study, deoxynivalenol (DON) in aqueous solution was exposed to gaseous ozone for periods ranging from 0 to 20 min. The degradation efficiency and cytotoxicity of DON were investigated after being treated by ozone. The results showed that DON was rapidly degraded from 10.76 ± 0.09 mg/L to 0.22 ± 0.04 mg/L within 15 min (P < 0.05), representing a reduction of 97.95%, and no DON was detected after being exposed to 14.50 mg/L of ozone at a flow rate of 80 mL/min for 20 min. The degradation of DON depended on the ozone exposure time, and followed the first-order kinetic model (R2 = 0.9972). Human hepatic carcinoma (HepG2) and Henrietta Lacks (Hela) cells were used to evaluate the cytotoxicity of DON treated by ozone using the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The half-maximal inhibitory concentrations (IC50) values of DON on HepG2 and Hela cells were 2.10 and 1.33 mg/L after 48 h of exposure, respectively, and showed a dose-dependent manner. The cell vitalities of HepG2 and Hela cells on DON were both evidently improved after being exposed to ozone for 15 min, and there were no significant differences between the negative control and that treated at 20 min of ozone exposure. Gaseous ozone can potentially be used as a new method to detoxify DON in agricultural products.

Effect of low-ratio n-6/n-3 PUFA on blood glucose: a meta-analysis

OBJECTIVE

The aim of this meta-analysis was to investigate the effect of increasing dietary low-ratio n-6/n-3 polyunsaturated fatty acid (PUFA) intake on blood glucose and other related indicators.

METHODS

We systematically searched randomized controlled trials of low-ratio n-6/n-3 PUFA intervention on PubMed, Embase, Cochrane library and related references up to August 2018. The change values were calculated as the weighted mean difference (WMD) by using a random-effect model.

RESULTS

Eleven randomized controlled trials were included. No significant effect of dietary low-ratio n-6/n-3 PUFA supplementation was observed on fasting blood glucose (WMD: 0.057 mmol L^-1; 95% CI: -0.090 to 0.204 mmol L^-1), insulin (WMD: -0.757 mIU L^-1; 95% CI: -2.419 to 0.904 mIU L^-1), insulin resistance index (WMD: -0.201; 95% CI: -0.566 to 0.165), and glycosylated hemoglobin (WMD: -0.063%; 95% CI: -0.061 to 0.186%). Subgroup analysis showed that the effect of low-ratio n-6/n-3 PUFA on the reduction of the plasma insulin level in North America (WMD: -3.473 mIU L^-1; 95% CI: -5.760 to -1.185 mIU L^-1) was more obvious than that in Asian countries (WMD: -0.797 mIU L^-1; 95% CI: -2.497 to 0.902 mIU L^-1) and European countries (WMD: -0.063 mIU L^-1; 95% CI: -0.061 to 0.186 mIU L^-1). In the subgroup of diabetic subjects, low-ratio n-6/n-3 PUFA supplementation can decrease the plasma insulin level (WMD: -3.010 mIU L^-1; 95% CI: -5.371 to -0.648 mIU L^-1) and insulin resistance index (WMD: -0.460; 95% CI: -0.908 to -0.012). When the intervention period was longer than 8 weeks, low-ratio n-6/n-3 PUFA supplementation could also decrease the plasma insulin level (WMD: -2.782 mIU L^-1; 95% CI: -4.946 to -0.618 mIU L^-1). No significant publication bias was observed for all blood glucose and other related indicators as suggested by Begg's test and Egger's test.

CONCLUSION

Our meta-analysis found that low-ratio n-6/n-3 PUFA supplementation could improve the glucose metabolism by reducing the insulin and insulin resistance in the diabetic patients. Low-ratio n-6/n-3 PUFA supplementation could reduce the plasma insulin level when the supplementation duration was longer than 8 weeks.

Effect of Alkali Treatment on Structure and Properties of High Amylose Corn Starch Film

Alkali treatment is used for melt extrusion film formation with corn starch, but optimal conditions for this procedure are still unknown. In this study, the changes in properties and structure of high amylose corn starch (70%) films with different concentrations of sodium hydroxide (NaOH), prepared by melting extrusion, were investigated. With increasing sodium hydroxide concentrations, the tensile strength of the high-amylose starch film decreased gradually, while the elongation at break increased. The tensile strength of the high amylose starch (HAS) film with 2% NaOH-treatment was 10.03 MPa and its elongation at break was 40%. A 2% NaOH-treatment promoted the orderly rearrangement of starch molecules and formed an Eh-type crystal structure, which enlarged the spacing of the single helix structure, increased the molecular mobility of the starch, and slowed down the process of recrystallization; a 10% NaOH-treatment oxidized the hydroxyl groups of the high amylose corn starch during extrusion, formed a poly-carbonyl structure, and initiated the degradation and cross-linking of starch molecule chains.

miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via ABCA1

Cancer stem cells (CSCs) are responsible for the unrestrained cell growth and chemo-resistance of malignant tumors. Reports about miR-33a in different type of cancer are limited, and it remains elusive whether there is a link between miR-33a and chemo-resistance of CSCs. Here we report that Lgr5+ hepatocellular carcinoma (HCC) cells from primary tissues and cell lines behave similarly to CSCs and are chemo-resistant to doxorubicin. Significantly, reduced miR-33a expression is associated with the chemo-resistance of Lgr5+ HCC-CSCs, accompanied by an overexpression of ABCA1 which is identified as target of miR-33a by mainly using miRNA luciferase assay and western-blotting. We demonstrate that down-regulation of miR-33a expression directly contributes to chemo-resistance of Lgr5+ HCC-CSCs, and restoring miR-33a expression sensitizes them to doxorubicin via apoptosis by mainly using TUNEL assay, soft agar colony formation assay and xenograft assay. Additionally, reduced miR-33a expression in HCC tissues is associated with chemo-response and poor patient survival, which suggests the therapeutic potential of miR-33a. In conclusion, our work indicates that ectopic miR-33a expression sensitizes Lgr5+ HCC-CSCs to doxorubicin via direct targeting ABCA1, which sheds new light on understanding the mechanism of chemo-resistance in HCC-CSCs and contributes to development of potential therapeutics against HCC.

Preparation of high quality starch acetate under grinding and its influence mechanism

The goal of this study is to reveal mechanism of preparing high quality modified starch by advanced equipment in well-known modified starch enterprises. Corn starch was used as raw material to prepare starch acetate with low degree of substitution under grinding, and the effect of grinding on the quality of starch acetate was studied. The effects of grinding on structures and properties of native corn starch were investigated. The mechanochemical theory was used to analyze the influence mechanism of grinding on quality of starch acetate. The results showed that the reaction efficiency (RE) of starch acetate increased from 70.98% to 85.80% at 4 h of grinding, and other qualities (solubility and swelling power) also increased. However, RE and other qualities of starch acetate were very different at 12 and 20-60 h of grinding. The changes of structures and properties of native starch after grinding showed that grinding has a significant mechanochemical effect on corn starch granules. The models of starch molecules and granules were made to reveal the "secret" of these advanced equipment in well-known modified starch enterprises.

Effects of Organic Modification of Montmorillonite on the Properties of Hydroxypropyl Di-Starch Phosphate Films Prepared by Extrusion Blowing

The knowledge gained from starch-nanocomposite-film research has not been fully applied commercially because of the lack of appropriate industrial processing techniques for nanofillers and starch films. Three organically modified montmorillonites (OMMTs) were prepared using a semidry kneading method. The effects of the OMMTs on the structures and properties of starch nanocomposite films, prepared by extrusion blowing, were investigated. The X-ray diffraction (XRD) analysis results revealed that the OMMTs with various quaternary ammonium salts possessed differing layer structures and d-space values. The results of the XRD and Fourier-transform infrared spectroscopy (FT-IR) showed that the starch⁻OMMT interaction resulted in a structural change, namely the starch⁻OMMT films possessed a balanced exfoliated and intercalated nanostructure, while the starch⁻MMT film possessed an exfoliated nanostructure with non-intercalated montmorillonite (MMT). The results of the solid-state nuclear magnetic resonance (NMR) analysis suggested that the starch-OMMT nanocomposite possessed comparatively large quantities of single-helix structures and micro-ordered amorphous regions. The starch⁻OMMT films exhibited good tensile strength (TS) (maximum of 6.09 MPa) and water barrier properties (minimum of 3.48 × 10−10 g·m·m−2·s−1·Pa−1). This study indicates that the addition of OMMTs is a promising strategy to improve the properties of starch films.