Safety Assessment of Starch Nanoparticles as an Emulsifier in Human Skin Cells, 3D Cultured Artificial Skin, and Human Skin.

Emulsion systems are widely used in various industries, including the cosmetic, pharmaceutical, and food industries, because they require emulsifiers to stabilize the inherently unstable contact between oil and water. Although emulsifiers are included in many products, excessive use of emulsifiers destroys skin barriers and causes contact dermatitis. Accordingly, the consumer demand for cosmetic products made from natural ingredients with biocompatibility and biodegradability has increased. Starch in the form of solid nanosized particles is considered an attractive emulsifier that forms and stabilizes Pickering emulsion. Chemical modification of nanosized starch via acid hydrolysis can effectively provide higher emulsion stability. However, typical acid hydrolysis limits the industrial application of starch due to its high time consumption and low recovery. In previous studies, the effects of starch nanoparticles (SNPs) prepared by treatment with acidic dry heat, which overcomes these limitations, on the formation and stability of Pickering emulsions were reported. In this study, we evaluated the safety of SNPs in skin cell lines, 3D cultured skin, and human skin. We found that the cytotoxicity of SNPs in both HaCaT cells and HDF cells could be controlled by neutralization. We also observed that SNPs did not induce structural abnormalities on 3D cultured skin and did not permeate across micropig skin tissue or human skin membranes. Furthermore, patches loaded with SNPs were found to belong in the "No irritation" category because they did not cause any irritation when placed on human skin. Overall, the study results suggest that SNPs can be used as a safe emulsifier in various industries, including in cosmetics.

Ulmus macrocarpa Hance Extracts Attenuated H2O2 and UVB-Induced Skin Photo-Aging by Activating Antioxidant Enzymes and Inhibiting MAPK Pathways.

To protect from reactive oxygen species (ROS) damages, skin cells have evolved to have antioxidant enzymes, such as copper and zinc-dependent superoxide dismutase (SOD1), mitochondrial manganese-dependent superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR), and suppressed the expression of matrix metalloproteinases (MMPs) through the mitogen-activated protein kinase (MAPK) signaling pathways, such as c-Jun N-terminal kinase (JNK) and p38. Bioactive compounds analyses were performed using a high-performance liquid chromatography-photodiode array detector (HPLC-PDA) system. The antioxidant activity of Ulmus macrocarpa Hance (UMH) extracts was estimated in vitro. The anti-aging activity of UMH extracts was estimated in vivo using the SKH-1 hairless mice. The UMH extracts reduced the H2O2-induced intracellular ROS production and the cell damages in human dermal fibroblasts (HDFs). Moreover, the H2O2-induced phosphorylation of JNK and p38 was detected in HDF and UMH extracts blocked the phosphorylation. These results suggest that UMH extracts can reduce the expression of MMPs and the reduced MMPs lead to the inhibition of collagen degradation. In addition, oral administration of the UMH extracts decreased the depth, thickness, and length of wrinkles on UVB exposed hairless mice. Therefore, UMH extracts play an advantage of the functional materials in antioxidant and anti-aging of skin.

Preparation of catechin-starch nanoparticles composites and its application as a Pickering emulsion stabilizer.

Starch is a biopolymer commonly used for nanoparticle synthesis. Starch nanoparticles (SNPs) have potential as encapsulation agents and Pickering emulsion stabilizers. Here, we prepared SNPs by dry heating under mildly acidic conditions to encapsulate catechin. Catechin (30 mg) and SNPs (50-150 mg) were dispersed in distilled water and freeze-dried to prepare catechin-SNP composites. Isothermal titration calorimetry and Fourier-transform infrared spectroscopy revealed that the binding of catechin to SNP may involve spontaneous hydrogen bonding and hydrophobic interactions. SNPs exhibited encapsulation efficiency for catechin, with 100 % catechin retention when 150 mg of SNP was used to prepare the composites. The catechin-SNP composites had a particle size of 54.2-74.9 nm. X-ray diffraction analysis revealed the formation of small amounts of inclusion complexes in catechin-SNP composites. As the amount of SNPs added for encapsulation increased, the catechin encapsulated in the SNP composites exhibited higher water solubility and UV stability than the pure catechin. The catechin-SNP composite with 150 mg of catechin exhibited the highest contact angle (51.37°) and formed a stable emulsion without notable droplet size changes. Therefore, catechin-SNP composites improved the encapsulation efficiency, water-solubility, stability of catechins, and Pickering emulsion stability.

Debranched waxy maize resistant dextrin: Synthesis, ethanol fractionation, crystallization, and characterization.

Waxy maize (Zea mays L.) dextrins (WMD), prepared by enzymatic debranching, were fractionated through precipitation in different concentrations of aqueous ethanol (50 %, 60 %, and 80 %). The fractionated WMDs were then crystallized at 4 °C or 50 °C for 2 days to prepare resistant dextrins (RD). Recovery yield, chain distribution, crystalline structure, thermal transition, and in vitro digestibility of the fractionated/crystallized WMDs were evaluated. Crystallization at 4 °C resulted in higher yields (>90 %) than that at 50 °C, regardless of the fractionation condition. The chain profile of the dextrins recovered at different temperatures appeared similar, but the longer chains had a greater tendency to associate. Crystal arrangement (A- or B-type) depended on the fractionation and crystallization conditions. Most crystals showed a typical B-type arrangement, except for the crystals prepared at 50 °C with 80 % ethanol (A-type). The enzyme resistance ranged from 49.9 % to 92.4 % depending on the fractionation and crystallization conditions.

Effect of fatty acid chain length on physicochemical properties of starch nanocomposites obtained via nanoprecipitation.

To evaluate the effect of elaborate difference in the hydrophobicity of core material on encapsulation process and physicochemical properties of the composites, composites of starch and FA with various chain lengths (C:12-22) were prepared via nanoprecipitation. X-ray diffraction analyses revealed that all composites had a Vh-amylose crystalline unit cell, but the chain length of FA did not induce a clear change in crystallinity or the hydrodynamic mean diameter of the composites. As the chain length of FA increased from 12 to 22, FA content in the composites increased from 1.69 to 14.85 mg/g composite. The absorption analyses of Rose Bengal on the composite surfaces revealed that their hydrophobicity increased with increasing chain length of FA. The incorporation of FA enhanced the emulsification activity of the composites, and this result revealed that the composites could be applied as an emulsification agent. For longer FA, composite storage stability increased, but the release of FA by in vitro digestion was delayed.

Enhancing stability and bioavailability of sulforaphene in radish seed extracts using nanoemulsion made with high oleic sunflower oil.

The effect of nanoemulsions on the stability and bioavailability of sulforaphene (SFEN) in radish seed extract (RSE) was investigated. Four types of oil were used as lipid ingredients of the nanoemulsions: soybean, high oleic acid sunflower, coconut, and hydrogenated palm oils. SFEN in RSE nanoemulsions showed greater stability to temperature, acid, and alkaline conditions than SFEN in RSE suspended in water (RSE-S). Particularly under alkaline conditions, the half-life of SFEN in the nanoemulsion with high oleic sunflower oil (RSE-HOSO) was 8 times longer than that of RSE-S. Furthermore, in the pharmacokinetics study, it was observed that AUC0-8 increased and oral clearance (CL/F) decreased significantly in rats orally administered RSE-HOSO compared with RSE-S (p < 0.05). This study indicates that the type of oil used in nanoemulsions affects the stability and bioavailability of SFEN in RSE. These results may provide a guideline for the development of functional foods containing RSE. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01304-2.

Evidence of Greater Competitive Fitness of Erwinia amylovora over E. pyrifoliae in Korean Isolates.

Erwinia amylovora and E. pyrifoliae are the causative agents of destructive diseases in both apple and pear trees viz. fire blight and black shoot blight, respectively. Since the introduction of fire blight in Korea in 2015, the occurrence of both pathogens has been independently reported. The co-incidence of these diseases is highly probable given the co-existence of their pathogenic bacteria in the same trees or orchards in a city/ district. Hence, this study evaluated whether both diseases occurred in neighboring orchards and whether they occurred together in a single orchard. The competition and virulence of the two pathogens was compared using growth rates in vitro and in planta. Importantly, E amylovora showed significantly higher colony numbers than E. pyrifoliae when they were co-cultured in liquid media and co-inoculated into immature apple fruits and seedlings. In a comparison of the usage of major carbon sources, which are abundant in immature apple fruits and seedlings, E. amylovora also showed better growth rates than E. pyrifoliae. In virulence assays, including motility and a hypersensitive response (HR), E. amylovora demonstrated a larger diameter of travel from the inoculation site than E. pyrifoliae in both swarming and swimming motilities. E. amylovora elicited a HR in tobacco leaves when diluted from 1:1 to 1:16 but E. pyrifoliae does not elicit a HR when diluted at 1:16. Therefore, E. amylovora was concluded to have a greater competitive fitness than E. pyrifoliae.

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.

Application of starch nanoparticles as host materials for encapsulation of curcumin: Effect of citric acid modification.

To encapsulate curcumin, absolute ethanolic curcumin solution with various content (300-1200 µg) was added to aqueous dispersion of citric acid-modified starch nanoparticles (M.SNPs) with various contents (0.5-2.5%), and then ethanol of the mixture was evaporated by nitrogen gas purge for 40 min (ethanol content decreased to 1%). SNPs (100 mg) could encapsulate 75.7 µg of curcumin in matrices of the composite, while 100 mg of M.SNPs could encapsulate 144.9 µg of curcumin. The XRD results revealed that curcumin was amorphously encapsulated in the composite, and hydrogen bond formation between M.SNPs and curcumin was one of the major driving forces for encapsulation as suggested by FT-IR. The composites had a spherical shape and mean particle size of the composites was increased from 136.3 to 255.3 nm with higher curcumin content in the matrices of composites. UV, pH, and thermal stability of curcumin significantly enhanced by the encapsulation, which was further increased when using M.SNPs and/or higher content of host materials. For the release of curcumin in simulated intestinal fluid digestion, release mechanism explained by Korsmeyer-Peppas model. For M.SNPs, k value was decreased from 13.097 to 2.938 as addition level of host material increased from 0.5 to 2.5%.

Fabrication of citric acid-modified starch nanoparticles to improve their thermal stability and hydrophobicity.

Starch nanoparticles (SNPs) were reacted at 130 °C for 1.5 h in the presence of citric acid (30 %) to enhance their thermal stability and hydrophobicity. Citric acid content in SNP was controlled by washing with different concentrations of ethanol (95 %, 70 % and 60 %) for 2, 5 and 10 min and then subjected to heat treatment at 130 °C. After the modification, the peak at 1732 cm-1 representing ester bond was observed via FT-IR, and the intensity of the peak was decreased with a lower ethanol content in washing medium. For the 60 % ethanol condition, the granular structure was promptly fragmented into particles less than 50 nm in the aqueous solution. The modification enhanced the thermal stability and hydrophobicity of the SNPs. The modified SNPs was used as a nano-vehicle wall material for encapsulating beta-carotene as a model hydrophobic material. Approximately 80 % beta-carotene was encapsulated in the modified SNPs.

Effects of the chemical and physical reaction conditions on the formation of nanocomposites made of starch and stearic acid.

To evaluate the reaction conditions on the physicochemical properties of composites of starch and stearic acid, composites were prepared under reaction conditions that varied the starch concentration (0.5, 1, 3%), stearic acid addition level (5, 10, 25 mg), stearic acid addition rate (2, 4, 8, 16 mL/min), and temperature (70, 80, 90 °C). All conditions significantly impacted the recovery, mean particle size, and zeta potential of samples. Specifically, a higher starch concentration and temperature significantly increased the recovery of stearic acid, but the mean particle size of the composite increased with higher stearic acid addition level and starch concentration. Stearic acid content in the composite exhibited a significant correlation with zeta potential (r = 0.818, p = 0.001). During enzymatic digestion for 20 min, 8% of the stearic acid was released from the composite. Approximately 10 % of the stearic acid was degraded after 36 h of storage at 50°C under 75 % relative humidity.

Starch nanoparticles produced via acidic dry heat treatment as a stabilizer for a Pickering emulsion: Influence of the physical properties of particles.

To evaluate the effect of the starch particle size on the stability of a Pickering emulsion, starch particles with various mean diameters were prepared using dry heat treatment under mildly acidic conditions. As addition level of acid increased, mean diameter of starch particles decreased from 23,100 to 15.7 nm, and contact angle of water droplet on the starch film increased from12 to 42.7°. Confocal microscopy revealed that a cohesive layer of starch particles with diameter of 28.6 nm surrounded the oil droplets, which may stabilize the emulsion. For starch particles smaller than 33.5 nm, the emulsion stability index increased up to approximately 95 % when starch content was higher than 9.1 %. For 16.7 % starch content, starch particles (< 33.5 nm) could form a stable emulsion with oil content of up to 61 %. For the emulsion stabilized by starch with 28.6 nm, it was stable when subjected to heating and freeze-thawing treatment.

Controlled fragmentation of starch into nanoparticles using a dry heating treatment under mildly acidic conditions.

Normal corn starch was treated with acidic ethanol solution with various concentrations of ethanol (0, 10, 30, 50 and 95%) and acid (0.0026, 0.0053 and 0.0079M) and then subjected to a dry heating treatment for 1, 2 and 4h at 130°C to prepare starch nanoparticles. Size of nanoparticles was determined using DLS (dynamic light scattering). FT-IR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction) and TEM (transmission electron microscopy) were used to determine the structure and morphology of starch nanoparticles. As the ethanol concentration decreased, the starch granule readily fragmented into smaller particles when simply dispersed in water, and this was possibly by the preferential hydrolysis of the starch chains in the amorphous region. A higher ethanol concentration (50 and 95%) did not produce homogenous nanoparticles, however 30% ethanol concentration produced uniform nanoparticles with a mean diameter of 46.4nm. The treatment condition (30% ethanol) partially broke the long-range crystalline order but left the short range order of the spherical nanoparticles intact. However, lower ethanol (<30%) concentrations induced severe damages in the both crystalline structures (long and short range) of starch granule.

Radical scavenging-linked anti-adipogenic activity of Alnus firma extracts.

The purpose of the present study was to investigate the antioxidant activity and anti-adipogenic effect of extracts from Alnus firma (A. firma), which is an edible plant that grows in mountainous areas. The total phenolic, flavonoid and anthocyanin content as well as the antioxidant activity of a 70% ethanolic extract of A. firma (AFE) was assessed. Furthermore, the effects of AFE on lipid accumulation and reactive oxygen species (ROS) production during adipogenesis of 3T3-L1 cells were investigated. The results revealed that the total phenolic, flavonoid and pro-anthocyanidin content of AFE as 436.26±3.30 mg gallic acid equivalents/g, 73.82±0.54 mg quercetin equivalents/g and 149.25±6.06 mg catechin equivalents/g, respectively. In addition, AFE exerted significant antioxidant effects in terms of 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, reducing power, oxygen radical absorbance capacity and nitric oxide radical scavenging activity. As for its anti-adipogenic activity, AFE significantly inhibited ROS production and lipid accumulation during adipogenesis of 3T3-L1 cells compared with those in control cells. In addition, AFE regulated adipogenic transcription factors including peroxisome proliferator­activated receptor-γ, CCAAT/enhance-binding protein α and adipocyte protein 2. These results indicated that A. firma is a potential candidate for a functional food supplement.

Starch nanoparticles resulting from combination of dry heating under mildly acidic conditions and homogenization.

To modify starch granular structure, normal maize starch was subjected to dry heating with various amounts of 1.0M HCl (1.2, 1.4 or 1.6mL) and different treatment times (2, 4 or 8h). For all reaction conditions, at least 80% of the starch substance was recovered, and amylose and amylopectin B1 chains were preferentially cleaved. As acidic condition and/or treatment time increased, the treated granules were readily fragmented by homogenization. The treatment appeared to alter short-range crystalline structure (FT-IR), but long-range crystalline structure (XRD) remained intact. Homogenization for 60min fragmented the treated starch granules (subjected to reaction condition of 1.4mL/4h, 1.6mL/2h, and 1.6mL/4h) into nanoparticles consisting of individual platelet-like and spherical particles with diameters less than 100nm. However, the fragmentation caused obvious damage in the long-range crystalline structure of starch nanoparticles, while the short-range chain associations remained relatively intact.

Volatile composition and sensory characteristics of onion powders prepared by convective drying.

Volatile composition and sensory characteristics of onion powders prepared by convective drying at different temperatures (50, 70, and 90°C) were investigated. Dipropyl disulfide was the major volatile compound in fresh onion (77.70% of total volatile compounds). However it was considerably lost during drying, reaching 6.93-32.25µg/g solids. Dipropyl disulfide showed a positive correlation with green sensory attribute perceived by descriptive sensory analysis. Thiophenes, which were responsible for caramel and sweet attributes, were produced by drying especially when the drying temperature was high. Aldehydes, another type of volatile compound found in fresh onion, showed a positive correlation with humidity. The aldehyde content in dried onion was the highest at the lowest drying temperature, possibly because the aldehydes were produced by the residual enzymes in fresh onion. Using a low temperature for drying was ideal to retain the aroma of fresh onion.

Evaluation of Antioxidant and Antimicrobial Activities of Ethanol Extracts of Three Kinds of Strawberries.

The antioxidant and antimicrobial activities of three kinds of strawberry ethanol extracts from Robus corchorifolius L. f. (RCL), Rubus parvifolius L. var. parvifolius (RPL), and Duchesnea chrysantha Miq. (DCM) were investigated. The RPL was highest (P<0.05) in phenolic, flavonoid, and anthocyanin contents. 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activities of RPL and DCM extracts were higher than that of RCL (P<0.05). Hydrogen peroxide scavenging activity of RPL was high compared to DCM and RCL (P<0.05). RCL exhibited a significant (P<0.05) potent antioxidant activity in nitric oxide radical inhibition. Inhibition diameter zone (nearest mm) of extracts against the test bacteria ranged from 11.5 in RCL to 12.5 in DCM against Staphylococcus aureus, from 10.5 in RCL to 13.5 in DCM against Streptococcus pneumoniae, from 8.5 in DCM to 10.5 in RCL against Escherichia coli, and the same inhibition of 10 mm in three of the extracts against Klebsiella pneumoniae. However, there was no inhibition against fungi Aspergillus niger and Candida albicans. Three of the extracts had the same minimum inhibitory concentration values of 12.50, 12.50, and 6.25 µg/mL against S. aureus, K. pneumoniae, and S. pneumoniae, respectively. On the other hand, MIC values of 12.50, 12.50, and 6.50 µg/mL were recorded for RPL, DCM, and RCL against E. coli, respectively. The result of present study revealed that extracts from three kinds of strawberries could be potential candidates as antioxidant and antimicrobial sources for functional food industries.

Preparation and characterization of corn starch-ß-carotene composites.

Starch-ß-carotene composites were generated by drop-wise addition of ethanol comprising varying ß-carotene contents (5, 10, or 20mg) into starch pastes (1, 3, or 5% w/v) to improve water-dispersibility and stability of ß-carotene. The mean diameter of the composites was less than 900 nm, allowing particles to be homogeneously dispersed in aqueous media for over two weeks without sedimentation. X-ray diffraction and differential scanning calorimetry analysis confirmed the composite mainly consisted of Vh-amylose, amorphous starch matrices, and starch-ß-carotene ordered structures. Both amorphous matrices and Vh-amylose structures in the composite were readily digested within 20 min in vitro digestion, while highly ordered structures, which melted between 132 and 159 °C, exhibited inhibited and/or delayed enzymatic digestion. As more ß-carotene was incorporated into the composite, the ß-carotene content of the ordered structure was increased. Formation of starch-ß-carotene composites also appeared to enhance the stability of ß-carotene against chemical oxidation.

Production of starch nanoparticles using normal maize starch via heat-moisture treatment under mildly acidic conditions and homogenization.

Normal maize starch was subjected to heat-moisture treatment (HMT) under mildly acidic conditions (0.000, 0.050, or 0.075M H2SO4) for various treatment times (3, 5, or 8h) followed by homogenization up to 60min to prepare nanoparticles. The combination of HMT (0.075M, for 8h) and homogenization (60min) produced nanoparticles with diameters of less than 50nm at a yield higher than 80%. X-ray diffractometry and size-exclusion chromatography revealed that HMT under mildly acidic conditions selectively hydrolyzed the starch chains (especially amylose and/or long chains of amylopectin) in the amorphous region of the granules without significant damage to the crystalline structure, however, modification of the molecular structure in the amorphous region increased fragility of the granules during homogenization. Homogenization for 60min caused obvious damage in the long-range crystalline structure of the HMT starch (0.15N, for 8h), while the short-range chain associations (FT-IR) remained intact.

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.