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Oil-in-water nanoemulsions stabilized by food-grade biopolymer emulsifiers (modified starches) were fabricated using high-pressure homogenization in an effort to improve the stability and bioaccessibility of β-carotene. Physicochemical and biological properties of β-carotene nanoemulsions were investigated considering the particle size, β-carotene retention, and in vitro digestion. During 30 days of storage at different conditions, the mean diameters of the emulsion systems were increased by 30-85%. The retention of β-carotene in nanoemulsions was significantly higher compared to that of the β-carotene dispersed in bulk oil. After in vitro digestion, the bioaccessibility of β-carotene was increased from 3.1% to 35.6% through nanoencapsulation. The results also indicated that modified starch with high dispersed molecular density led to a higher retention but lower bioaccessibility of β-carotene in nanoemulsions. This could be due to the thick and dense interfacial layer around the oil droplets. This result provides useful information for developing protection and delivery systems for carotenoids.

The aim of this work was to determine if the molecular structure of starch from tomato ( Solanum lycopersicum L.) is influenced by fruit physiology and carbohydrate metabolism. The effect of fruit size, fruit ripening behavior, and assimilate availability on starch granule accumulation was examined in nine tomato samples. The percentage of (14)C-glucose partitioning to starch was similar among samples, but starch contents varied 10-fold, suggesting differences in metabolism. In contrast, granule size (10-20 microm), amylose content (19-23%), degree of crystallinity (26-31%), and enthalpy of gelatinization (14.8-17.2 degrees C) were similar. Some differences in structure were detected in starch from the largest and smallest fruit using more sensitive analyses such as thermal properties, chain length distribution of amylopectin, and susceptibility to in vitro alpha-amylase digestion. However, overall, our results suggest that granule characteristics are highly conserved in tomato fruit, and we conclude that this is likely due to inherent metabolic constraints.

Physicochemistry and structural studies of two types of japonica rice, low amylose Calmochi-101 (CM101) and intermediate amylose M-202 (M202), were conducted to determine similarities and differences between the rices perhaps attributable to amylose content differences. The rheological behavior of the gelation and pasting processes of flours and starches was determined with high accuracy and precision using a controlled stress rheometer. Fat and protein, although minor constituents of milled rice, were shown to have significant effects on the physicochemical and pasting properties of starches and flours. Removal of protein and lipids with aqueous alkaline or detergent solutions caused lower pasting temperatures and higher overall viscosity in both starches, compared with their respective flours. There was less viscosity difference between M202 flour and its starch when isolated by enzymatic hydrolysis of protein. The protease did not reduce internally bound lipids, suggesting that fats help to determine pasting properties of rice flours and their respective starches. Structural integrity differences in individual granules of waxy and nonwaxy rice flours, starches, and whole raw, soaked, and cooked milled grain were revealed by fracture analysis and scanning electron microscopy. Calmochi 101 and M202 did not differ in weight-averaged molar mass (M w ) and root-mean-square radii (R z ) between flours and starches, as determined by high-performance size exclusion chromatography (HPSEC) and multiple-angle laser light scattering (MALLS) (Park, I.; Ibanez, A. M.; Shoemaker, C. F. Starch 2007, 59, 69-77).

Dimethyl sulfoxide (DMSO), with either 50 mM LiBr, 10% water, or both, was used as solvent for multi-angle laser-light scattering (MALLS) batch mode analysis of rice starch, and amylopectin and amylose weight-average molecular weight (Mw). DMSO/50 mM LiBr was a better solvent for these measurements than was DMSO/10% water, based on this solvent's ability to dissolve starch and to reduce the size of starch aggregates. Starch concentration decreased and amylose:amylopectin ratio increased when starch suspended in DMSO was centrifuged or filtered prior to size-exclusion chromatography (SEC)-MALLS analysis. A higher amylose:amylopectin ratio made starch more soluble, and the higher this ratio, the lower the Mw of eluted amylopectin. For SEC analysis of Mw, fractions of starch amylopectin and amylose dispersed in DMSO-based solvents yielded better results than starch dispersed directly into the solvents, because dispersion of these fractions decreased starch aggregation. When these two starch components were fractionated and then dissolved separately in DMSO/50 mM LiBr, the Mw of dispersed amylopectin ranged from 40 to 50 million, and that of amylose was ca. 3 million, whereas starch from three rice varieties of varying amylose content ranged from 60 to 130 million. We recommend that SEC evaluation of amylopectin and amylose be accomplished with fractionated samples as in this study; such evaluations were superior to evaluations of natural mixtures of amylopectin and amylose.

© 2015 American Chemical Society. The aim of this work was to examine agronomic, compositional, and functional changes in rice (Oryza sativa L. cv. Nipponbare) grains from plants grown under low-to-moderate salinity stress in the greenhouse. Plants were grown in sodium chloride-containing soil (2 or 4 dS/m2electrical conductivity), which was imposed 4-weeks after transplant (called Seedling EC2 and EC4) or after the appearance of the anthers (called Anthesis EC2 and EC4). The former simulates field conditions while the latter permits observation of the isolated effect of salt on grain filling processes. Key findings of this study are the following: (i) Plants showed adaptive responses to prolonged salt treatment with no negative effects on grain weight or fertility. Seedling EC2 plants had more panicles and enhanced caryopsis dimensions, while surprisingly, Seedling EC4 plants did not differ from the control group in the agronomic parameters measured. (ii) Grain starch increased in Seedling EC4 (32.6%) and Anthesis EC2 (39%), respectively, suggesting a stimulatory effect of salt on starch accumulation. (iii) The salinity treatment of 2 dS/m2was better tolerated at anthesis than the 4 dS/m2treatment as the latter led to reduced grain weight (28.8%) and seed fertility (19.4%) and compensatory increases in protein (20.1%) and nitrogen (19.8%) contents. (iv) Although some salinity treatments led to changes in starch content, these did not alter starch fine structure, morphology, or composition. We observed no differences in reducing sugar and amylose content or starch granule size distribution among any of the treatments. The only alterations in starch were limited to small changes in thermal properties and glucan chain distribution, which were only seen in the Anthesis EC4 treatment. This similarity of compositional and functional features was supported by multivariate analysis of all variables measured, which suggested that differences due to treatments were minimal. Overall, this study documents the specific response of rice under defined conditions, and illustrates that the plasticity of plant response to mild stress is complex and highly context-dependent, even under greenhouse conditions in which other potential environmental stress impacts are minimized.

Low-pressure propoxylation of reduced whey permeate (RWP) with different water contents (12.7 and 33.4%) under alkaline conditions afforded polyether polyols (PEP) which have been characterized by their 1H-NMR, HPLC, hydroxyl number, viscosity, unsaturation content, and alpha color. The results were compared with those from lactitol- and sucrose-based polyether polyols (LPEP and SPEP, respectively). Compared with LPEP and SPEP, polyether polyols from reduced whey permeate (RWP-PEP) showed relatively higher hydroxyl number, lower viscosity, and a similar degree of unsaturation. RWP-PEP was generally darker in color. In addition, polyurethane rigid foams (PURFs) from RWP-PEP, LPEP, and commercial sucrose−glycerin-based polyols (Voranol-PEP) were prepared and characterized. All PURFs made from RWP-PEP have low densities (from 28 to 29 kg/m3) and high closed cell contents (>73%). Compressive strength ranged from 13 to 17 kg × 1000/m2 at 10% deformation. These foams have similar thermal stability as the commer...

The enzymatic and chemical oxidation reaction in olive oil produces many volatile carbonyl compounds that contribute to the complex flavor of olive oil. A novel ultrahigh performance liquid chromatography (UHPLC) method with dynamic headspace sampling and 2,4-dinitrophenylhydrazine (DNPH) derivatization were established to determine the volatile carbonyls in virgin olive oil. Quantification of nine characteristic carbonyls (acetone, hexanal, E-2-hexenal, octanal, E-2-octenal, nonanal, E-2-nonenal, E,E-2,4-nonadienal, and E,E-2,4-decadienal) was achieved using cyclopentanal as an internal standard. This method provides comparable linearity (R(2) = 0.9917-1.0000) and repeatability (less than 7.6% relative standard deviations) with solid phase microextraction gas chromatography (SPME-GC). The relative standard deviations (%RSD) of all applied carbonyl standards were lower than 7.6%. The limits of detection (LOD) and quantification (LOQ) were in the ranges of 1.6-150.1 and 4.8-906.1 μg/kg. The recoveries obtained for olive oil samples were in the range of 81.0-115.3%. To show the potential of this method on the quantification of other volatile carbonyls that were not included in this study, GC-electron ionization mass spectrometry (GC-EI/MS) was employed to identify the derivatized carbonyls (carbonyl (2,4-DNPH) hydrazones) while peak assignments were made on the basis of elution sequences and peak areas. This method provided feasibility of using LC to determine volatile carbonyls in oil matrices, which can be applied to exam the degree of lipid oxidation and evaluate the sensory properties of VOO and other edible oils.

Fragrance encapsulated in small particles of20 μm diameter is preferred for use in textiles. This study demonstrated that the proper combination of surfactants could produce small and heat-stable emulsion droplets with chitosan that could be spray-dried to produce microcapsules. The microcapsules were able to be deposited onto cotton using water or detergents. It was found that stable emulsion was obtained when Tween 40 and Span 20 were used as compound emulsifiers with the ratio of 4:1 (w/w). The optimum conditions were 1% (w/w) chitosan in acetic acid with the compound emulsifiers of 3-7% (w/w) in the oil, and the inlet temperature for spray-drying was 150 °C. The encapsulation efficiency for orange oil was90% with a 1:2 (w/w) ratio of oil to chitosan. Microcapsules had a mean diameter of20 μm and regular particle morphology. The orange oil in the microcapsules was well retained in cotton fabrics after washing in normal detergent solution. The process and products are low in cost, nontoxic, biocompatible, and biodegradable.

The mixture of peppermint oil (PO) with medium-chain triacylglycerol was emulsified in water and stabilized with a food-grade biopolymer, modified starch, to form PO nanoemulsions. The effects of emulsifying conditions including homogenization pressure, the number of processing cycles, and oil loading on the mean diameters and viscosities of nanoemulsions were characterized by dynamic light scattering, optical microscopy, and rheological measurements. The formulated PO nanoemulsions with mean diameters normally

Konjac glucomannan (KG, neutral), carboxymethylcellulose (CMC, negatively charged), and chitosan (positively charged) were added to cornstarch dispersions to study the effect of polysaccharide-starch interactions on starch gelatinization properties. Pasting and retrogradation properties were measured with a rheometer and DSC. Swelling properties of the starch granules were determined by solubility index, swelling power, and particle size distribution. Depending on the nature of the different polysaccharides, viscosities of cornstarch dispersions were affected differently. The particle size distributions were not influenced by the addition of any of the polysaccharides. Swelling results showed that the KG and CMC molecules interacted with the released or partly released amylose in the cornstarch dispersions. This was correlated with the short-term retrogradation of the starch pastes being retarded by the additions of KG and CMC. However, the chitosan molecules appeared not to associate with the amylose, so the retrogradation of the chitosan-cornstarch dispersions was not retarded.

This study investigated the antioxidant content and activity of phenolic acids, anthocyanins, α-tocopherol and γ-oryzanol in pigmented rice (black and red rice) brans. After methanolic extraction, the DPPH free radical scavenging activity and antioxidant activity were measured. The pigmented rice bran extract had a greater reducing power than a normal rice bran extract from a long grain white rice. All bran extracts were highly effective in inhibiting linoleic acid peroxidation (60-85%). High-performance liquid chromatography (HPLC) analysis of antioxidants in rice bran found that γ-oryzanol (39-63%) and phenolic acids (33-43%) were the major antioxidants in all bran samples, and black rice bran also contained anthocyanins 18-26%. HPLC analysis of anthocyanins showed that pigmented bran was rich in cyanidin-3-glucoside (58-95%). Ferulic acid was the dominant phenolic acid in the rice bran samples. Black rice bran contained gallic, hydroxybenzoic, and protocatechuic acids in higher contents than red rice bran and normal rice bran. Furthermore, the addition of 5% black rice bran to wheat flour used for making bread produced a marked increase in the free radical scavenging and antioxidant activity compared to a control bread.