Resistant starch as a carrier for oral colon-targeting drug matrix system

Proteomic identification and quantification of Clostridium perfringens enterotoxin using a stable isotope-labelled peptide via liquid chromatography-tandem mass spectrometry

PURPOSE

Detection of Clostridium perfringens enterotoxin (CPE) in human stool is critical evidence of food poisoning. However, processing patient-derived samples is difficult and very few methods exist to confirm the presence of CPE. In this study, a technique was developed using proteomic analysis to identify and quantify CPE in artificial gut fluid as an alternative.

METHODS

The standard CPE was spiked into artificial gut fluids, and effective methods were developed by employing both a stable isotope-labelled internal standard peptide and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Proteotypic peptide EILDLAAATER formed by tryptic digestion was selected for quantitation of CPE. The peptide was identified using product ion spectra. Although the nontoxic peptides originating from CPE showed very low detectability in extraction and tryptic digestion, they could be detected with sufficient sensitivity using the method we developed. Based on a spiked recovery test at two concentrations (50 and 200 µg/kg), the recovery values were 85 and 78%, respectively. The relative standard deviations of repeatability and within-laboratory reproducibility were less than 8 and 11%, respectively. These standard deviations satisfied the criteria of the Japanese validation guidelines for residues (MHLW 2010, Director Notice, Syoku-An No. 1224-1). The limit of quantification (LOQ) was estimated to be 50 µg/kg. The combination of the product ion spectra and relative ion ratio supported CPE identification at the LOQ level.

CONCLUSIONS

To the best of our knowledge, this is the first report of proteomic analysis of CPE using LC-MS/MS. The method would greatly help in assessing CPE reliably.

Chemically modified phytoglycogen: Physicochemical characterizations and applications to encapsulate curcumin

Phytoglycogen (PG), a water-soluble glycogen-like α-d-glucan, exists as natural dendritic nanoparticles which are known as a promising solubility enhancer and delivery vehicle for lipophilic compounds. However, the practical applications of PG in food and pharmaceutical fields are limited by their high hydrophilicity and relatively low encapsulation efficiency compared with other delivery systems. The objectives of this work were to chemically modify native PG nanoparticles with hydrophobic groups and to characterize their physicochemical properties, as well as to evaluate the application feasibility of modified PG (mPG) nanoparticles as a carrier for hydrophobic bioactive compounds. The surface hydroxyl groups of PG nanoparticles were capped with various anhydrides, e.g., acetic, valeric, and N-caprylic, to obtain the PG nanoparticles with different hydrophobicity. Successful modification by acyl groups was evidenced by both Fourier-transform infrared and nuclear magnetic resonance spectroscopies. The mPG nanoparticles exhibited a more compact structure and homogeneous size distribution as revealed by dynamic light scattering measurement and visualized by transmission electron microscope, while their size slightly increased with the chain length of anhydride. Rheological measurement revealed that the viscosity of mPG at low shear rate was increased with the increase of degree of substitution due to the intermolecular hydrophobic association. A novel pH-driven method to load curcumin showed significantly higher encapsulation efficiency and greater antioxidant activity compared with traditional ethanol mediated loading method. Hydrophobic modification of natural dendritic PG nanostructures demonstrates promising potential to develop food-grade nanocarriers for lipophilic bioactive compounds with improved bioactivity.

Functionality of Food Components and Emerging Technologies

This review article introduces nutrition and functional food ingredients, explaining the widely cited terms of bioactivity, bioaccessibility, and bioavailability. The factors affecting these critical properties of food components are analyzed together with their interaction and preservation during processing. Ultimately, the effect of emerging (non-thermal) technologies on different food components (proteins, carbohydrates, lipids, minerals, vitamins, polyphenols, glucosinolates, polyphenols, aroma compounds, and enzymes) is discussed in spite of preserving their functional properties. Non-thermal technologies can maintain the bioavailability of food components, improve their functional and technological properties, and increase the recovery yields from agricultural products. However, the optimization of operational parameters is vital to avoid degradation of macromolecules and the oxidation of labile compounds.

Towards effective and stable probiotics

BACKGROUND

Probiotics are live microorganisms, generally either lactobacilli or bifidobacteria, which when administered in adequate amounts confer a health benefit to the host [1]. Due to the growing evidence of health benefits associated with their use, probiotics are of increasing interest and represent now a significant growth area in the functional foods industry [2]. However, to be effective, orally administered probiotics should survive preparation of dosage forms and passage through acidic environment of the gastrointestinal tract (GIT). Reaching the intestine, these microorganisms should be able to establish themselves, remain viable and perform their beneficial actions. In this context, oral formulations have to protect probiotic bacteria from gastric acidity and delay their release in the small intestine in order to allow their complete release in the colon.

OBJECTIVE

To evaluate effects of starch formulations of lactobacilli on their survival in gastric environment and probiotic properties.

METHODS

Nineteen Lactobacillus strains belonging to the species L. fermentum (14 strains), L. plantarum (4 strains), and L. rhamnosus (1 strain), were isolated from dairy products and probiotics, and were used in this study. Lactobacilli were cultured in de Man, Rogosa, Sharpe (MRS) broth (Merck, Germany) under microaerobic conditions at 37°C.Amylolytic activity of lactobacilli, cultured for 3-5 days on MRS agar supplemented with 1% soluble potato starch (SPS), was determined with iodine reagent (0.01 M I2-KI solution).Loading in starch was performed with L. plantarum 8PA3 bacteria ("Dry lactobacterin", Perm, Russia), which were resuspended to the concentration 1010 cells/mL in 10 mL of 0.85% NaCl solution and added to 90 mL of 2.5% SPS solution. Resulting mixture was frozen at -18°C and then lyophilized (Martin Christ Alpha 1-2 LDplus, Germany).Atomic force microscopy (AFM) images of formulated L. plantarum 8PA3 cells were acquired in air by a Solver P47H atomic force microscope (NT-MDT, Moscow, Russia).Starch swelling and dissolution was studied in simulated colonic fluid (SCF), prepared according to [3] and in distilled water (pH = 6.0) as control. Amylase from Aspergillus oryzae (A8220, Sigma) was added to the solutions to study the influence of amylase. The formulation form was examined visually during 14 h incubation time.Fluorescence microscopy images were obtained with a Leica DM6000B (Germany) fluorescent microscope using Leica FW4000 software.L. plantarum 8PA3 loaded in SPS were placed either in HCl solution (pH 2), or in 2% oxgall bile solution, or in 0.85% NaCl solution. Viability was tested after 2, 4 and 6 h incubation at 37°C by plating diluted aliquots onto MRS agar with subsequent counting of bacterial colony forming units (CFU). In addition, viability was determined using LIVE/DEAD BacLight bacterial viability kit L-7012 (Molecular Probes, Invitrogen) as described elsewhere [4]. Fluorescence in the stained samples was estimated with BD FACS Canto II (USA) flow cytometer or fluorescent microscope.Nitric oxide (NO) production was assessed with DAF-FM DA and DAA fluorescent dyes as described earlier [4]. Each experiment was performed in triplicate.

RESULTS

In the present study we studied the probiotic composition comprising of SPS and bacteria L. plantarum 8PA3. We used AFM to confirm effective fixation of the cells to carbohydrate. The compositions were found to swell quickly (~5 min) in aqueous solutions either containing amylase, or not. Tested starch formulations disintegrated during the first 5-10 min of incubation in amylase solutions whereas in amylase-free probes dissolution was less intensive (after ~30 min). Amylolysis of starch excipients was less pronounced in aqueous amylase solution than in SCF, supplemented with amylase. None of 19 studied Lactobacillus strains hydrolyzed SPS when growing on MRS agar supplemented with it. The amount of viable L. plantarum 8PA3 cells formulated with SPS was high and did not change when stored for 6 months at 4°C. The bacterial viability tests also demonstrated that after 6 h treatment with 2% bile or HCl (pH 2) L. plantarum 8PA3 exhibited increased sensitivity (viability 14% and 0.4%, respectively). However, in similar conditions no significant differences were noticed between bacterial viability obtained for formulated with starch and non-formulated bacteria. Furthermore, we showed that loading into SPS had no effect on bacterial production of nitric oxide (NO) - a pluripotent regulatory molecule in human organism.

CONCLUSIONS

Overall, the results strongly support that formulation with polymeric matrices on the basis of SPS represent an appealing technology of probiotics production. It provides slow release of bacteria in target environment and does not alter their viability and NO biosynthesis. However, SPS excipient does not preserve the bacteria from harsh conditions of upper GIT. Therefore, we conclude that for oral administration the composition should be loaded in acid-resistant capsules.

Resistant starch contents of native and heat-moisture treated jackfruit seed starch

Native jackfruit seed starch (JFS) contains 30% w/w type II resistant starch (RS2) and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT) was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC), temperatures, and times. Moisture levels of 20-25%, together with temperatures 80-110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2%) was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16). FT-IR peak ratio at 1047/1022 cm(-1) suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in T g and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged.

Triblock polymeric micelles as carriers for anti-inflammatory drug delivery

This study evaluated the properties of poly(ethylene oxide)-b-poly(n-butyl acrylate)-b-poly(acrylic acid) (PEO-PnBA-PAA) polymeric micelles as carriers for anti-inflammatory drugs (prednisolone and budesonide). The micelles comprising a hydrophobic PnBA core and a PEO/PAA corona showed average diameter less than 40 nm. The size of the drug-loaded micelles did not change during eight hours into media that mimic physiological fluids indicating high colloidal stability. The calculation of Flory-Huggins parameter showed greater compatibility between budesonide and micellar core suggesting its location in the micellar core, whereas prednisolone was located also into the interface layer. This observation correlated further with slower release of budesonide, especially in acid medium (pH = 1.2). The inclusion of budesonide into micelles showed significant protective effect against the cytotoxic damage induced by the co-cultivation of differentiated human EOL-1 and HT-29 cells. This study revealed the capacity of PEO-PnBA-PAA terpolymer as carrier of nanosized micelles suitable for oral delivery of anti-inflammatory drugs.

Resistant starch film-coated microparticles for an oral colon-specific polypeptide delivery system and its release behaviors

For the delivery of bioactive components to the colon, an oral colon-specific controlled release system coated with a resistant starch-based film through aqueous dispersion coating process was developed. Starch was modified by a high-temperature-pressure reaction, enzymatic debranching, and retrogradation, resulting in a dramatic increase in the resistibility against enzymatic digestion (meaning the formation of resistant starch, specifically RS3). This increase could be associated with an increase in the relative crystallinity, a greater amount of starch molecular aggregation structure, and the formation of a compact mass fractal structure, resulting from the treatment. The microparticles coated with this RS3 film showed an excellent controlled release property. In streptozotocin (STZ)-induced type II diabetic rats, the RS3 film-coated insulin-loaded microparticles exhibited the ability to steadily decrease the plasma glucose level initially and then maintain the plasma glucose level within the normal range for total 14-22 h with different insulin dosages after oral administration; no glycopenia or glycemic fluctuation was observed. Therefore, the potential of this new RS3 film-coated microparticle system has been demonstrated for the accurate delivery of bioactive polypeptides or protein to the colon.