Interaction of curcumin and bixin with β-cyclodextrin: complexation methods, stability, and applications in food

This work aimed to compare methods for the formation of complexes of bixin and curcumin with β-cyclodextrin (β-CD) and to evaluate the stability of the complexes formed by these methods and their food applications. The stoichiometric relationship between curcumin and β-CD was 1:2 and that between bixin and β-CD was 1:1. Curcumin-β-CD and bixin-β-CD complexes formed by kneading, coprecipitation, and simple mixing were evaluated by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), or nuclear magnetic resonance (NMR-H). For both curcumin and bixin, the best method of complexation was coprecipitation. Complexation of colorants with β-CD promoted an intensification of color and increased water solubility; however, stabilization in the presence of light occurred only for bixin. Application of curcumin-β-CD in cheese and yogurt and bixin-β-CD in the curd did not alter the initial characteristics of the products, which were sensorialy well accepted. Therefore, the complexation of these natural colorants with β-CD favors their use in low-fat foods, broadening the field of industrial application.     

Evaluation of microplate and bench-scale β-glucosidase assays for reproducibility, comparability, kinetics, and homogenization methods in two soils

Enzyme assays that use fluorescently labeled substrates and microplate formats have been incorporated into laboratory protocols to improve sensitivity and reduce the time and labor involved in traditional bench-scale analyses. Microplate protocols vary, and the methods have not been evaluated systematically for comparability and reproducibility. In this study, p-nitrophenol (pNP)-based and 4-methylumbelliferone (MUF)-based microplate methods for estimating β-glucosidase activity were compared in two soils with different properties. Microplate method reproducibility was evaluated in replicate soil suspensions, and Michaelis–Menten kinetics for the microplate assays were compared to those of a standard pNP bench-scale assay. The effect of soil sample sonication on reproducibility was determined for the MUF microplate method. The MUF microplate method was reproducible in five replicate soil suspensions, but the pNP microplate method showed greater variability. The K _m Michaelis–Menten constant was significantly different in the microplate methods compared to the bench method. Enzyme activities measured by the MUF and bench methods were comparable, but the pNP microplate method resulted in more variable measurements and was less sensitive in the soils studied. Sonication of soil at an intensity of 15 W ml^?1 resulted in higher (MUF) measurements, but greater variability. The effects of high background absorbance on the reproducibility, sensitivity, and accuracy of the pNP microplate method do not support this method as a substitute for the standard bench method. A robust comparison study of the MUF microplate method across laboratories is recommended to further validate its use in comparative analyses.     

s-Allyl cysteine, s-ethyl cysteine, and s-propyl cysteine alleviate β-amyloid, glycative, and oxidative injury in brain of mice treated by D-galactose

The neuroprotective effects of s-allyl cysteine, s-ethyl cysteine, and s-propyl cysteine in D-galactose (DG)-treated mice were examined. DG treatment increased the formation of Aβ(1-40) and Aβ(1-42), enhanced mRNA expression of β-amyloid precursor protein (APP) and β-site APP cleavage enzyme 1 (BACE1), and reduced neprilysin expression in brain (P < 0.05); however, the intake of three test compounds significantly decreased the production of Aβ(1-40) and Aβ(1-42) and suppressed the expression of APP and BACE1 (P < 0.05). DG treatments declined brain protein kinase C (PKC) activity and mRNA expression (P < 0.05). Intake of test compounds significantly retained PKC activity, and the expression of PKC-α and PKC-γ (P < 0.05). DG treatments elevated brain activity and mRNA expression of aldose reductase (AR) and sorbitol dehydrogenase as well as increased brain levels of carboxymethyllysine (CML), pentosidine, sorbitol, and fructose (P < 0.05). Test compounds significantly lowered AR activity, AR expression, and CML and pentosidine levels (P < 0.05). DG treatments also significantly increased the formation of reactive oxygen species (ROS) and protein carbonyl and decreased the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (P < 0.05); however, the intake of test compounds in DG-treated mice significantly decreased ROS and protein carbonyl levels and restored brain GPX, SOD, and catalase activities (P < 0.05). These findings support that these compounds via their anti-Aβ, antiglycative, and antioxidative effects were potent agents against the progression of neurodegenerative disorders such as Alzheimer's disease.     

Interactional effects of β-glucan, starch, and protein in heated oat slurries on viscosity and in vitro bile acid binding

Three major oat components, β-glucan, starch, and protein, and their interactions were evaluated for the impact on viscosity of heated oat slurries and in vitro bile acid binding. Oat flour from the experimental oat line "N979" (7.45% β-glucan) was mixed with water and heated to make oat slurry. Heated oat slurries were treated with α-amylase, lichenase, and/or proteinase to remove starch, β-glucan, and/or protein. Oat slurries treated with lichenase or lichenase combined with α-amylase and/or proteinase reduced the molecular weight of β-glucan. Heat and enzymatic treatment of oat slurries reduced the peak and final viscosities compared with the control. The control bound the least amount of bile acids (p < 0.05); heating of oat flour improved the binding. Heated oat slurries treated with lichenase or lichenase combined with α-amylase and/or proteinase bound the least amount of bile acid, indicating the contribution of β-glucan to binding. Oat slurries treated with proteinase or proteinase and α-amylase together improved the bile acid binding, indicating the possible contribution of protein to binding. These results illustrate that β-glucan was the major contributor to viscosity and in vitro bile acid binding in heated oat slurries; however, interactions with other components, such as protein and starch, indicate the importance of evaluating oat components as whole system.     

Effects of copper on the decomposition of plant residues,microbial biomass,and β-glucosidase activity in soils

Abstract

Two types of soils (Brown Lowland soil and Ando soil), which were artificially enriched with different amounts of Cu, were incubated with or without pulverized orchard grass for 12 weeks at 25°C. For both soils with and without orchard grass amendment, the amount of CO₂ evolved over the 12-week period of incubation decreased by the enrichment with Cu at a concentration exceeding 1,000 mg kg^?1 soil. The decrease of the mineralization of added orchard grass in the Cu-enriched soil was conspicuous especially during the initial period of incubation. The amount of microbial biomass C at the end of the incubation was significantly reduced by the Cu enrichment regardless of the amendment with orchard grass. The relative decrease of the soil microbial biomass was much greater than that of the soil respiration. The amount of biomass C was negatively correlated with the amount of 0.1 M CaCl₂-extractable Cu as a logarithmic function. On the other hand, the β-glucosidase activity at the end of the incubation was not significantly affected by the presence of Cu in the soils without orchard grass amendment and increased with the increase in the amount of enriched Cu in the orchard grass-amended soils.     

Retention during processing and bioaccessibility of β-carotene in high β-carotene transgenic cassava root

Cassava is a root crop that serves as a primary caloric source for many African communities despite its low content of β-carotene (βC). Carotenoid content of roots from wild type (WT) and three transgenic lines with high βC were compared after cooking and preparation of nonfermented and fermented flours according to traditional African methods. The various methods of processing all decreased βC content per gram dry weight regardless of genotype. The greatest loss of βC occurred during preparation of gari (dry fermentation followed by roasting) from WT and transgenic lines. The quantities of βC in cooked transgenic cassava root that partitioned into mixed micelles during in vitro digestion and transported into Caco-2 cells were significantly greater than those for identically processed WT root. These results suggest that transgenic high βC cassava will provide individuals with greater quantities of bioaccessible βC.     

Reactions between β-lactoglobulin and genipin: kinetics and characterization of the products

In this paper, we present the first detailed study of the reaction kinetics and the characterization of the products from the endothermic reactions between β-lactoglobulin and genipin. The effects of the concentration, temperature, and pH were investigated. In the temperature range studied, the reaction was approximately a pseudo-first-order with respect to genipin and 0.22-order and -0.24-order with respect to β-lactoglobulin for pH 6.75 and 10.5 with corresponding activation energy (E(a)) estimated to be 66.2 ± 3.8 and 9.40 ± 0.36 kJ/mol, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis studies, validated by matrix-assisted laser desorption ionization-time of flight mass spectrometry, showed the presence of oligomeric, i.e., di-, tri-, quadri-, and pentameric, forms of cross-linked β-lactoglobulin by genipin at neutral but not alkaline pH; however, an extensive cross-linked network was not observed, consistent with the atomic force microscopy images. It was demonstrated that the reaction temperature and the concentration of genipin but not that of β-lactoglobulin positively affected the extent of the cross-linking reactions.     

Potential nitrification, nitrate reductase, and β-galactosidase activities as indicators of restoration of ecological functions in a Zn-contaminated soil

The present study was conducted to assess the possible restoration of different ecological functions in a Zn-contaminated soil. Experiments were conducted in a soil microcosm contaminated with 350?mg?kg^?1 of Zn and in an uncontaminated control microcosm, both incubated for 4?months. At regular intervals, potential nitrification, nitrate reductase, and β-galactosidase activity were determined. All these activities were significantly reduced just after Zn contamination in contaminated microcosms compared to the activities of the control, but then increased. In order to confirm that the restoration of ecological functions was not due to an aging phenomenon, a reinoculation protocol was also applied. A significant restoration was found for β-galactosidase activity, while for nitrate reductase activity and potential nitrification, there was a clear shift of dose–response curves but with partial overlap of the EC₅₀ ranges estimation, thus indicating that different ecological functions are restored over time in Zn-contaminated soils.     

Spatial distribution of glomalin-related soil protein and its relationships with root mycorrhization,soil aggregates,carbohydrates, activity of protease and β-glucosidase in the rhizosphere of Citrus unshiu

Relationships between the spatial distributions of glomalin-related soil protein (GRSP) and soil aggregates, carbohydrates or relevant enzymes are poorly studied. We found that two categories of GRSP, the easily extractable Bradford-reactive soil protein (EE-BRSP) and total BRSP (T-BRSP), respectively ranged between 0.3–0.6 and 0.5–0.8 mg/g DW soil, and these two BRSPs decreased with the increase of soil depth (0–40 cm) in the rhizosphere of a 22-year-old Citrus unshiu orchard. Both EE-BRSP and T-BRSP were significantly positively correlated with mycorrhization, 0.25–0.50 mm soil water-stable aggregates, water-extractable or hydrolyzable carbohydrates, and β-glucosidase, but significantly negatively correlated with protease. Our results demonstrate that the spatial distribution of GRSP is significantly affected by mycorrhization, soil carbohydrate, β-glucosidase and protease.     

Variability of hydrolysis of β-, αs1-, and αs2-caseins by 10 strains of Streptococcus thermophilus and resulting bioactive peptides

Milk proteins contain numerous potential bioactive peptides, which may be released by digestive proteases or by the proteolytic system of lactic acid bacteria during food processing. The capacity of Streptococcus thermophilus to generate peptides, especially bioactive peptides, from bovine caseins was investigated. Strains expressing various levels of the cell envelope proteinase, PrtS, were incubated with α(s1)-, α(s2)-, or β-casein. Analysis of the supernatants by LC-ESI-MS/MS showed that the β-casein was preferentially hydrolyzed, followed by α(s2)-casein and then α(s1)-casein. Numbers and types of peptides released were strain-dependent. Hydrolysis appeared to be linked with the accessibility of different casein regions by protease. Analysis of bonds hydrolyzed in the region 1-23 of α(s1)-casein suggests that PrtS is at least in part responsible for the peptide production. Finally, among the generated peptides, 13 peptides from β-casein, 5 from α(s2)-casein, and 2 from α(s1)-casein have been reported as bioactive, 15 of them being angiotensin-converting enzyme inhibitors.     

Characterization and antioxidant activity of the complex of tea polyphenols and oat β-glucan

Few data are available about the effects of complexation of polyphenols with polysaccharide on their bioavailability. The complex of tea polyphenols (TP) with oat β-glucan was characterized by ultraviolet-visible spectrometry, Fourier transform infrared spectrometry, differential scanning calorimetry, atomic force microscopy, and solid-state (13)C NMR spectroscopy. The results indicated that the bonds which governed the interaction between TP and oat β-glucan were strong hydrogen bonds. The in vitro antioxidant activity of TP, β-glucan, their complex, and physical mixture was assessed using four systems, namely, DPPH(?), OH(?), and O(2)(?-) scavenging activities and reducing power. The complexation and blending of TP and β-glucan exhibited different impacts on the index of in vitro and in vivo antioxidant capacities. In the concentration range of 0.5-2.5 mg mL(-1), the complex had highest O(2)(?-) scavenging activity, whereas the highest OH(?) scavenging activity was found with the physical mixture. For antioxidant testing in vivo, there was no significant difference between the complex and the physical mixture in terms of glutathione peroxidase activity and levels of malondialdehyde and total antioxidant capacity in serums. However, the complex exhibited much higher activities of superoxide dismutase and glutathione peroxidase in livers than the physical mixture. The present study provided a deeper understanding of the influence of molecular interaction between TP and oat β-glucan on their antioxidant activities.     

Differentiation and geographical distribution of β-amylase isozyme in barley

This study reports on the investigation of the polymorphism and geographical distribution of -amylase isozymes by isoelectric-focusing (IEF) analysis in samples of world barley. The isozyme pattern of high thermostability type A and low thermostability type C varieties was restricted in isozyme type II. However, the isozyme pattern of the middle thermostability type B varieties was polymorphic. The -amylase isozyme of 1,554 lines of the middle thermostability group was investigated next. Besides types I and II, new isozyme types III and IV were observed. Most lines were grouped into type II in all growing areas, except for Europe where type I and type II were even in number. Types III and IV were observed in only one line in India and Afghanistan, respectively. In Northern Europe, especially in Denmark, type I was major. It was concluded that a mutant IEF isozyme type I originated from the type II prototype of the thermostability B group in Northern Europe.     

Effects of different origins and harvesting time on vitamin C,tocopherols, and tocotrienols in sea buckthorn (Hippophaë rhamnoides) berries

Vitamin C, tocopherols, and tocotrienols in berries of wild and cultivated sea buckthorn (Hippopha? rhamnoides L.) of different origins and harvesting dates were determined with HPLC. Wild berries of subsp. sinensis, native to China, contained 5-10 times more vitamin C in the juice fraction than the berries of subsp. rhamnoides from Europe and subsp. mongolica from Russia (4-13 vs 0.02-2 g/L juice). Genetic background and berry-harvesting date were two primary factors determining the vitamin C content in the berries. Crossing different subspecies influenced the vitamin C content to some extent. For bushes cultivated in southwest Finland, the best berry-harvesting date for high vitamin C content was the end of August. The seeds of subsp. sinensis contained less tocopherols and tocotrienols (average 130 mg/kg) compared with seeds of subsp. rhamnoides (average 290 mg/kg) and mongolica (average 250 mg/kg). The fruit flesh of sinensis berries had contents of tocopherols and tocotrienols 2-3 times higher than those found in the other two subspecies (120 mg/kg vs 40 mg/kg in rhamnoides and 50 mg/kg in mongolica). The fresh whole berries of subsp. sinensis were clearly the best source of total tocopherols and tocotrienols. The total content of tocopherols and tocotrienols in the soft parts of the berries reached the maximum level around early- to mid-September, whereas the content in seeds continued to increase until the end of November. The excellent combination of the highest content of vitamin C and tocopherols and tocotrienols makes the berries of subsp. sinensis an optimal raw material for nutritional investigation as a candidate for functional foods with special antioxidative properties.     

Nonionic surfactant and interfacial structure impact crystallinity and stability of β-carotene loaded lipid nanodispersions

The stability, crystallization, and melting behavior of canola stearin (CaSt) solid lipid nanoparticle dispersions (SLN) and canola oil-in-water emulsions (COE) with 10 wt % Poloxamer 188 (P188) or Tween 20 (T20) with and without 0.1 wt % β-carotene (BC) were investigated. Particles or droplets with diameters in the range of 115 nm were formed and stable for up to 90 days at 4 or 20 °C. Polymorphism was affected by surfactant type; that is, only β versus both β' and β were observed for the P188 and T20 SLN, respectively. According to Cryo-TEM, the emulsions and SLN were spherical versus platelet-like structures, respectively, with differences observed between SLN with P188 or T20. More surfactant was interfacially adsorbed in the SLN versus COE. Incorporation of BC at 0.1 wt % had no impact on SLN or COE size, polymorphism, or melting behavior. Less BC degradation was observed for the SLN versus COE and during storage at 4 versus 20 °C (p < 0.05).     

Effect of cooking on concentrations of β-estradiol and metabolites in model matrices and beef

Because beef food products are generally cooked prior to consumption, the behavior of chemicals in these cooked foods is important in estimating human exposure. The heat stability of the natural estrogen β-estradiol (β-E2) and its metabolites α-estradiol (α-E2), estrone (E1), and several catechol estrogens was examined in heated vegetable oil and aqueous solutions. The chemicals were also incorporated into regular and extra lean ground beef and subjected to cooking. E1 and E2 were stable in aqueous solutions at 100°C, whereas the catechol estrogens exhibited first-order decay curves with half-lives of 2-10 min. Their stability improved to the same level as the other test chemicals when an antioxidant was added to the solution, suggesting that their disappearance was due to oxidation rather than thermal degradation. E1 and E2 were also stable in heated vegetable oil (160-180°C), whereas catechol estrogen decreased 30-50% over the 2 h duration of the experiments. Chemical losses from cooked beef appear to be related to the fat content of the beef, with greater losses occurring in regular ground beef (25-30%), compared to extra lean ground beef (5-20%). This study shows that cooking reduces but does not eliminate the potential for dietary exposure to growth promoters in ground beef.     

Interaction between β-casein and whey proteins as a function of pH and salt concentration

The effectiveness of β-casein as a chaperone in the aggregation of whey proteins was investigated. β-Casein altered heat-induced aggregation as shown by a reduction in turbidity of β-lactoglobulin, α-lactalbumin, and bovine serum albumin (BSA) solutions. The pH of the mixtures greatly affected how much β-casein reduced the turbidity of the solutions; the maximum reductions in turbidity were observed at pH 6.0. Reducing the pH decreased the effectiveness of β-casein as a chaperone. An increase in ionic strength by the addition of NaCl or CaCl(2) also decreased the effectiveness of the chaperone. The addition of CaCl(2) had a larger effect than the addition of NaCl. The chaperone effect was seen at temperatures up to 145 °C. Differential scanning calorimetry (DSC) showed that β-casein did not alter the denaturation temperature of β-lactoglobulin. The kinetics curves for loss of native protein and turbidity development showed that β-casein did not function by slowing the aggregation process. It was concluded that β-casein competes with whey protein in the aggregate process and the aggregates formed in the presence of β-casein are smaller in size than those formed during whey protein self-aggregation. The formation of smaller aggregates gives rise to less turbid, more soluble protein solutions.     

Matrix effects in analysis of β-agonists with LC-MS/MS: influence of analyte concentration, sample source, and SPE type

The synergistic influences of analyte concentration, sample source, and solid-phase extraction (SPE) type on matrix effects in the multiresidue analyses of eight β-agonists with LC-ESI-MS/MS were evaluated. Porcine muscle and liver extracts and urine from diverse sources were purified by strong or mixed-mode cation exchange and molecularly imprinted polymer SPE cartridges, respectively. Three spiked concentrations (2, 10, and 20 ng/mL) of eight β-agonists in the purified matrices and the different sample sources were analyzed. The results show that for most β-agonists there are significant differences in matrix effects between analyte concentrations or sample sources (P < 0.05), whereas there is no significant difference in matrix effects between different SPE cartridges (P > 0.05). Results from main effects testing indicated that analyte concentration was the main effector.     

Effect of pH, NaCl, CaCl2 and temperature on self-assembly of β-lactoglobulin into nanofibrils: a central composite design study

The ability of certain globular proteins to self-assemble into amyloid-like fibrils in vitro opens opportunities for the development of new biomaterials with unique functional properties, like highly efficient gelation and viscosity enhancement. This work explored the individual and interacting effects of pH (1 to 3), NaCl (0-100 mM), CaCl(2) (0-80 mM) and heating temperature (80 to 120 °C) on the kinetics of β-lactoglobulin self-assembly and the morphology of resulting nanofibrils. Statistically significant (p < 0.05) interactions included CaCl(2)*temperature, NaCl*pH, CaCl(2)*pH, temperature*pH and NaCl*CaCl(2). Particularly notable was the very rapid self-assembly at pH 3 and the highly nonlinear effect of pH on self-assembly kinetics. Nanofibril morphologies ranged from long and semiflexible or curled and twisted to short and irregular. There did not seem to be a link between the kinetics of fibril formation and the morphology of fibrils, except at pH 3, where self-assembly was very rapid and fibrils were short and irregular, suggesting haphazard, uncontrolled self-assembly.     

Changes in Physical,Chemical, and Microbiological Properties During the Two-Stage Composting of Green Waste due to the Addition of β-cyclodextrin

This research determined whether addition of β-cyclodextrin (β-CD; 0, 0.15, or 0.25%) improved the two-stage composting of green waste (GW). The following parameters were measured during composting or in the final product: moisture content; volume; biochemical and chemical oxygen demand; humic substances; C/N_solid and C/N_soluble; microbial numbers (culturable bacteria, actinomycetes, and fungi); enzyme activities (pectinase and xylanase); microbial biomass carbon and nitrogen; degradation of organic components; contents of phosphorus (available and total), potassium, sodium, calcium, and magnesium; and toxicity to germinating seeds. The two-stage composting of GW was optimal with the addition of 0.15% β-CD. A mature and stable compost was obtained in only 28?days with the optimized two-stage composting rather than in the 90–270?days typically required for traditional composting.