Relation between textural attributes and surface leachate structural and compositional characteristics of cooked rice.

The objective of this study was to evaluate the leachate and textural characteristics of cooked rice, and the correlations between the leachate properties and texture attributes were also investigated. Cooked waxy rice had much higher total solids and amylopectin amount in leachate than the normal and high-amylose rice. For all varieties, the amylopectin chain length of the leachate was similar, excluding Dodam cultivar. The rheological characteristics of the leachate solutions were highly dependent on the amylopectin amount of the leachate. Regarding the textural characteristics, Dodam had the highest hardness and the lowest adhesiveness. The principal component analysis showed substantial differences in leachate and textural characteristics of Korean cooked rice according to its amylose content. The adhesiveness was positively and negatively correlated with amylopectin amount of leachate and the proportion of long amylopectin chains, respectively. These results indicated that the leachate characteristics of cooked rice significantly influenced its textural attributes. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01446-3.

Angelica gigas polysaccharide induces CR3-mediated macrophage activation and the cytotoxicity of natural killer cells against HCT-116 cells via NF-κB and MAPK signaling pathways.

Angelica gigas (A. gigas) is traditional medicinal herb that mainly exists in Korea and northeastern China. There have been relatively few studies conducted thus far on its polysaccharides and their bioactivities. We purified and described a novel water-soluble polysaccharide derived from A. gigas and investigated its immunoenhancing properties. The basic components of crude and purified polysaccharides (F1 and F2) were total sugar (41.07% - 70.55%), protein (1.12-10.33%), sulfate (2.9-5.5%), and uronic acids (0.5-31.05%) in total content. Our results demonstrated that the crude and fractions' molecular weights (Mw) varied from 42.2 to 285.2 × 103 g/mol. As the most effective polysaccharide, F2 significantly stimulated RAW264.7 cells to release nitric oxide (NO) and express several cytokines. Furthermore, F2 increased the expression of tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-É£), natural killer cytotoxicity receptors (NKp44), and granzyme-B in NK-92 cells and enhanced the cytotoxicity against HCT-116 cells. In our experiments, we found that F2 stimulated RAW264.7 cells and NK-92 cells via MAPK and NF-κB pathways. The monosaccharide and methylation analysis of the high immunostimulant F2 polysaccharide findings revealed that the polysaccharide was primarily composed of 1 â†’ 4, 1 â†’ 6, 1 â†’ 3, 6, 1 â†’ 3 and 1 â†’ 3, 4, 6 galactopyranose residues, 1 â†’ 3 arabinofuranose residues, 1 â†’ 4 glucopyranose residues. These results demonstrated that the F2 polysaccharide of A. gigas which possesses potential immunostimulatory attributes, could be used to create a novel functional food.

Cnidium officinale polysaccharide enhanced RAW 264.7 cells activation and NK-92 cells cytotoxicity against colon cancer via NF-κB and MAPKs signaling pathways.

In this study, Cnidium officinale-derived polysaccharides were isolated and investigated for their immune enhancing and anticancer activities. The isolated crude and its fractions, such as F1 and F2, contain carbohydrates (51.3-63.1%), sulfates (5.4-5.8%), proteins (1.5-7.1%), and uronic acids (2.1-26.9%). The molecular weight (Mw) of the polysaccharides ranged from 59.9 to 429.0 × 103 g/mol. The immunostimulatory activity of the polysaccharides was tested on RAW 264.7 cells, and the results showed that the F2 treatment notably enhanced pro-inflammatory activity in RAW 264.7 cells by increasing NO production and the expression of various cytokines. Furthermore, the influence of polysaccharide treatment on natural killer cells (NK-92) anticancer activities was investigated using a colon cancer cell line (HCT-116). Crude polysaccharide and its fractions showed no direct cytotoxicity to NK-92 and HCT-116 cells. However, the treatment of F2 showed an enhancement of NK-92 cells cytotoxicity against HCT-116 cells by upregulating the mRNA expression of IFN-γ, TNF-α, NKGp44, and granzyme-B. The western blot results showed that the induced RAW 264.7 cells activation and NK-92 cells cytotoxicity occur via NF-κB and MAPK signaling pathways. Overall, C. officinale-derived polysaccharides show potential as immunotherapeutic agents capable of enhancing pro-inflammatory macrophage signaling and activating NK-92 cells; thus, they could be useful for biomedical applications.

Structural characteristics of resistant starch-enriched rice during digestion and its effects on gut barrier function in high-fat induced obese mice.

Dietary supplementation with indigestible carbohydrates is known to improve the gut environment and prevent obesity and inflammatory diseases by modulating the gut microbiota. In previous work, we established a method for the production of resistant starch (RS)-enriched high-amylose rice (R-HAR) using citric acid. The present study aimed to evaluate changes in structural characteristics during digestion of R-HAR and its effects on the gut health. A three-step in vitro digestion and fermentation model was used, then, RS content, scanning electron microscopy, and branch chain length distribution were analyzed during in vitro digestion. During the digestion of R-HAR, the RS content increased, and the structure was predicted to have a greater impact on the gut microbiota and gut environment. To study the intestinal health effects of R-HAR, its anti-inflammatory and gut barrier integrity activities were assayed in HFD-induced mice. Intake of R-HAR suppressed colonic shortening and inflammatory responses induced by HFD. Furthermore, R-HAR exhibited gut barrier protective activity with an increase in tight junction protein levels. We determined that R-HAR may be a potentially beneficial intestinal environment improver, which may have various implications in the food industry as rice.

Structural and physicochemical properties of composites between starch nanoparticles and ß-carotene prepared via nanoprecipitation.

To apply starch nanoparticles (SNP) as host materials for ß-carotene encapsulation, aqueous SNP dispersions (10, 25, 50, and 100 mg/10 mL) and ß-carotene in acetone (10, 50, 100, 150, and 200 µg/mL) were mixed. The acetone in the mixture was evaporated to prepare SNP and ß-carotene composites, which were homogeneously dispersed in aqueous media with over 90 % solubility. When SNP content was higher than 50 mg, over 80 % of ß-carotene was encapsulated in the composite matrix. X-ray diffraction, nuclear magnetic resonance spectroscopy, and transmission electron microscopic analyses confirmed the micellar-shaped composite particles with diameters <120 nm and an amorphous structure. High SNP content in the composites enhanced ß-carotene stability under extremely hot and acidic conditions as well as against ultraviolet rays and oxidation reactions. The encapsulated ß-carotene was not readily released in simulated gastric fluid, but was gradually released in simulated intestinal fluid via SNP digestion in the composites.

Effect of molecular structure on phase transition behavior of rice starch with different amylose contents.

Phase transition behaviors in starch-water system and molecular structures of rice starches isolated from four Korean cultivars with different amylose contents were investigated and the importance of structural features affecting starch phase transitions was also explored. The Dodam starch with the highest average chain length of amylopectin (26.1), the highest proportion (24.3 %) of long chains (DP ≥ 37), and the lowest proportion (17.5 %) of short chains (DP 6-12) displayed the highest gelatinization and retrogradation temperatures. Enthalpies of ice freezing and melting, and glass transition temperature (Tg') of rice starches increased with increasing amylose content and decreasing proportion of short amylopectin chains because these structural features are related to a higher thermal stability of the starches. Ice melting temperature was also influenced by amylopectin chain structures. The results suggest that the phase transition behaviors of rice starches were highly influenced by their amylose content and amylopectin chain length distribution.

Influence of germination on physicochemical properties of flours from brown rice, oat, sorghum, and millet.

The changes in physiochemical properties of flours obtained from the four selected grains after germination were investigated. After germination, the sprout length of sorghum and millet was substantially larger than that of brown rice and oat. Germination led to a decrease in the apparent amylose content and swelling factor of flours. Gelatinization onset and peak temperatures increased after germination, while a slight decrease was found in conclusion temperature. Compared to the raw flours, the germinated flours derived from brown rice, sorghum, and millet had lower gelatinization enthalpy, whereas the germinated oat flour showed higher gelatinization enthalpy. Germination resulted in significant decrease in pasting parameters of the four flours. Amylose leaching of sorghum and millet flours increased after germination, while the brown rice and oat flours showed a significant decrease in amylose leaching. Results suggest that germination effectively altered the physicochemical properties of grain flours, which can be utilized as functional ingredient in the preparation of grain-based products.

Monitoring and risk assessment of tepraloxydim in banana (Musa paradisiaca) and sweet orange (Citrus sinensis).

This study was conducted to analyze the residue levels of tepraloxydim in banana and sweet orange. Successive liquid-liquid extraction and cartridge clean-up method for tepraloxydim determination in banana and sweet orange were developed and validated by HPLC. The developed method was validated, and the recovery and LOQ of tepraloxydim were 79.3-99.5% and 0.02 mg kg-1, respectively. Among the 48 banana and 34 sweet orange samples, tepraloxydim was detected in two (0.03 mg kg-1) and four samples (0.03-0.05 mg kg-1), respectively. A risk assessment of tepraloxydim in banana and sweet orange was conducted by calculating the percent ratio of estimated daily intake (EDI) and acceptable daily intake (ADI). The ADI of tepraloxydim was 0.05 mg kg-1 day-1, and the EDIs of it from banana and sweet orange were 6.3 × 10-6 and 5.1-8.5 × 10-6, respectively. The percent of EDI to ADI of tepraloxydim was 0.013 and 0.010-0.017%, respectively. These results showed that the tepraloxydim levels in this study might not be harmful to human beings.

Study on physical and mechanical properties of the biopolymer/silver based active nanocomposite films with antimicrobial activity.

Silver nanoparticles (AgNPs) were prepared by reducing AgNO3 using biopolymer pullulan as both a reducing and stabilizing agent. The prepared AgNPs solution was blended with pectin to make active nanocomposite films. The formation of AgNPs in the solution was confirmed by characteristic surface plasmon resonance (SPR) peak of AgNPs at 400-500 nm, using UV-vis absorption spectroscopy. The prepared composite and nanocomposite films were characterized using UV, FE-SEM, and FT-IR. In addition, films color, optical, water contact angle, water vapor permeability, mechanical and antimicrobial properties were evaluated. FE-SEM analysis showed uniform distribution of AgNPs in the resulting nanocomposites films. The presence of AgNPs could affect the physical and mechanical properties of the prepared films. The color, moisture content, water vapor barrier properties, hydrophobicity, thickness, and elongation at break of the films were significantly increased after formation of composite with AgNPs, but tensile strength and elastic modulus of the films were decreased. FT-IR results indicated that AgNPs had good compatibility with biopolymers. In addition, nanocomposite films, especially pullulan/AgNPs and pullulan/pectin/AgNPs films exhibited better antimicrobial activity against food born pathogens, which suggests that prepared nanocomposite films can be used as active food packaging material to maintain food safety and to improve shelf life of the packaged food.

Physical, textural and sensory characteristics of legume-based gluten-free muffin enriched with waxy rice flour.

Physical, textural, and sensory characteristics of the gluten-free muffins made of mungbean and cowpea flours enriched with waxy rice flour were investigated. Amylose content and pasting viscosity of legume-waxy rice flour blend (1:1) were lower than that of wheat flour. The number and area of gas cells of muffin containing legume flour was lower than that of control muffin with wheat flour. Legume-based muffins had low lightness value due to the presence of color components. Weight of the muffins containing legume was higher than that of control muffin, but their height and volume were lower than control. Legume-based muffins had greater crude ash and protein contents than control. Compared with control, muffin containing legume flour had significantly higher hardness and gumminess. In sensory evaluation, overall acceptance of muffin containing Okdang cultivar of cowpea was the highest among legume-based muffins, which was comparable to control muffin.

Analysis of Targeted Metabolites and Molecular Structure of Starch to Understand the Effect of Glutinous Rice Paste on Kimchi Fermentation.

Bachu (Chinese cabbage) kimchi, a Korean traditional fermented dish, were prepared with or without the addition of glutinous (waxy) rice paste and their characteristics including pH, total bacteria count, total starch content, sugar metabolites, and molecular structure of starch were examined periodically for 20 days to investigate the effect of adding glutinous rice paste to kimchi during fermentation. The pH and total bacteria count showed that the fermentation of kimchi added with glutinous rice paste (GRP kimchi) progressed a little more quickly than that of control kimchi without glutinous rice paste. The GRP kimchi had higher glucose content but lower fructose content than control kimchi. Interestingly, maltose was only detected in GRP kimchi during fermentation. The GRP kimchi contained much greater amount of mannitol throughout fermentation than control kimchi. Total starch content in GRP kimchi gradually decreased during fermentation, which might have contributed to its greater glucose content and the larger amount of maltose production. In GRP kimchi, peak height and area for all degrees of polymerization (DP) of starch decreased during fermentation and its average chain length decreased while the proportion of short chains increased as fermentation processed, indicating degradation of starch chains by enzymes presented in the kimchi.

Preparation and characterization of aqueous dispersions of dextrin and policosanol composites.

Policosanol (50-100mg) was dispersed in an aqueous solution (0.5-2.0% solids, w/v, 50 mL) of an amylomaize starch dextrin at 90°C under different conditions. The dispersion of the mixture was opaque but remained homogenous for up to 7 days at an ambient temperature. The precipitates obtained by centrifuging the dispersion (5,000 × g, 30 min) contained crystalline V-amylose complex of policosanol. The supernatant also contained policosanol but not in the complex form. Stepwise addition of policosanol and longer time complex formation increased the dispersible policosanol: about 95% by 30 min interval, 1.0% dextrin solution and 12h complex formation time. Among the dispersible policosanol (95%), 70% policosanol resided in the precipitates and 25% was in the supernatant, indicating the dextrin behaved as a stabilizer for the dispersed policosanol as well as a complex forming agent with policosanol. The policosanol dispersion was sonicated up to 30s to evaluate physical stability. Around 70% policosanol in the dispersion remained stable against the sonication treatment.