Examination of the Interaction of Chitosan and Oil-in-Water Emulsions Under Conditions Simulating the Digestive System Using Confocal Microscopy

Discussions on the Properties of Emulsion Prepared by Using an Amphoteric Chitosan as an Emulsifier

A typical emulsion contains oil and water phases, and these two phases can be combined by an emulsifier with both lipophilic and hydrophilic groups to form a mixture. If the component of water is more than oil, the mixture is termed as o/w emulsion. The water is called the continuous phase and the oil is called the dispersed phase. Oppositely, if the component of oil is more than water, the mixture is termed as w/o emulsion. The oil is called the continuous phase and the water is called the dispersed phase. Chitosan, which is biocompatible and non-toxic, was modified as an amphoteric emulsifier to replace sodium acrylates copolymer in the preparation of emulsions. Both sodium acrylates copolymer and the modified chitosan were used as emulsifiers, respectively, and the properties of moisturizing, transmittance, the number of bacteria, and emulsion stability were measured. The experimental results showed that the amount of amphoteric chitosan is less than that of sodium acrylate copolymer by 20% under a similar degree of emulsification. The measurement of spatial moisture showed the difference in equilibrium humidity was in the range of 2.05 to 2.20 gH2O/kg dry air, indicating that the moisture retention of the modified chitosan is better. In addition, the calculation of bacterial growth confirmed that the number of bacteria in the amphoteric chitosan emulsion and the sodium acrylate copolymer emulsion were 80 and 560, respectively. The emulsion stability was tested by the separation of oil and water phases in the diluted emulsion and by centrifugal accelerated sedimentation. The results showed that, for both emulsifiers, no separation of the oil and water phases occurred within one hour, and the stability of the modified chitosan emulsion was better. Therefore, the modified chitosan successfully substitutes sodium acrylates copolymer as an emulsifier in the preparation of emulsion.

Effects of carboxymethyl chitosan on physicochemical, rheological properties and in vitro digestibility of yam starch

The effects of carboxymethyl chitosan (CMCS) on the pasting, rheological, and physical properties of yam starch (YS) were investigated. Different concentrations of CMCS were added to the YS, followed by heating paste treatment at 95 °C. Then the blends were subjected to the determination of physicochemical, rheological properties and in vitro digestibility. Our results showed that CMCS reduced the paste viscosity of YS and the addition of CMCS did not effectively inhibit the movement of water molecules. Rheological measurements results showed that YS-CMCS blends exhibited shear thinning behavior. Furthermore, because of the presence of amylose inhibited the swelling of the starch and leaching of amylose, the addition of CMCS had no significant difference between solubility and swelling power of YS.

Ultrasound-Assisted Extraction of Chitosan from Squid Pen: Molecular Characterization and Fat Binding Capacity

Chitosan from squid (Loligo formosana) pens were prepared and characterized. First, ultrasonication condition was optimized for deproteinization of squid pens using central composite design (CCD) of response surface methodology (RSM). Squid pens were ultrasonicated at amplitude 69% for 41.46 min at the solid/solvent ratio of 1:18 yielded 34% (w/w) chitin with the lowest remaining protein. Therefore, ultrasonication effectively reduced the extraction time for chitin production from squid pens as compared to traditional method (5 hr). When the resultant chitin was subjected to deacetylation at different temperatures and times, yield and degree of deacetylation (DDA) of chitosan were in the range of 50% to 65% (w/w) and 78% to 90%. Intrinsic viscosity and molecular weight (MW) of chitosan were in the range of 3.2 to 6.52 dL/g and 1.2 × 10⁵ to 3.2 × 10⁵ Da, respectively. All the chitosans with different DDA were able to bind oil droplets under the mimicked pH condition of gastrointestinal tract. Chitosan produced by deacetylation at 130 °C for 2 hr (CH130-2) showed the optimum yield (54%) and had medium MW (1.5 × 10⁵ Da). DDA of CH130-2 determined using ¹ H-NMR was 89%, which was similar to that (87%) obtained from FTIR. XRD results showed destruction of chitin structure and decreased crystallinity index from 55% to 27% after deacetylation. CH130-2 stabilized the emulsion under the simulated gastrointestinal conditions. Therefore, it could be used as dietary fiber to control the adsorption of fat/oil in the human digestive tract. PRACTICAL APPLICATION: Chitin and chitosan are marketable products manufactured from crustacean shells. However, extraction of chitin is time consuming. Ultrasonication has been used for extraction of various biomolecules from different sources. It effectively lowers the processing time and enhances extraction yield. Therefore, application of ultrasonication with optimized condition using RSM could reduce extraction time and enhance yield of chitin from squid pen. Chitin from squid pen could be further converted to chitosan with high DDA. Chitosan was able to act as a dietary fiber and reduce fat absorption in gastrointestinal tract. Thus, this information is of benefit for squid processing industry to exploit squid pen, a processing byproduct.

In-vitro starch hydrolysis of chitosan incorporating whey protein and wheat starch composite gels

The study examined the influence of chitosan, incorporated into whey protein and wheat starch thermo gels, on the in-vitro hydrolysis of the polysaccharide. Gels were subjected to the following external conditions containing α-amylase at constant incubation temperature of 37 °C: In the first procedure, they were immersed in phosphate buffer (0.05 M) and maintained at pH 6.9 throughout the entire digestion. In the second instance, they were introduced into a salt solution, with pH and total volume adjusted at times in sync with the human gastrointestinal tract. Results indicate that low and medium molecular weight chitosan, in combination with whey protein, were effective at enhancing the protective barrier against starch degradation. Less maltose was liberated from gels containing medium molecular weight chitosan, as opposed to the low molecular weight counterpart, and results compare favorably with the outcome of the in-vitro digestion of binary whey protein and wheat starch composites.

A single oral dose of a polyglucosamine influences the bioavailability of [9-(14)C]-Oleic acid in adult female Göttingen minipigs

Background

Worldwide obesity has nearly doubled since 1980 and is a leading risk for global deaths, profoundly affecting morbidity, mortality, health-care costs, and professional and personal quality of life. Treatment of obesity and its consequences include lifestyle intervention, pharmacotherapy, and bariatric surgery. Polyglucosamines have been proposed as an alternative strategy for treating obesity, by reducing the amount of absorbed fat through interaction with dietary fat through various mechanisms. The objective of this study is to investigate the influence of polyglucosamine on the bioavailability of the model compound [9-¹⁴C]-oleic acid in female Göttingen minipigs.

Method

The study consisted of two treatment groups, each consisting of six adult female Göttingen minipigs with a catheterized vena jugularis to enable frequent blood sampling. One group served as the untreated group (control) and the other group was pre-treated with 2 tablets of 500 mg formoline L112. After 30 min, all animals were dosed orally with [9-¹⁴C]-oleic acid. Excreta and blood samples were collected for analysis of radioactivity from 48 h pre-dose up to 144 h post-dosing. At sacrifice, the liver and contents of the gastrointestinal tract were collected for radioanalysis.

Results

Upon treatment with polyglucosamine (formoline L112), the T_max of [¹⁴C]-oleic acid in plasma was shifted from 4 to 16 h, and the C_max decreased significantly from 14.1 μg/g to 3.3 μg/g. In addition, upon treatment with polyglucosamine the internal exposure to [¹⁴C]-oleic acid as reflected by the area under the curve during the 0–12 h post-dose time interval (AUC_0-12h), is significantly decreased to 32.9 % of the plasma value of [¹⁴C]-oleic acid in untreated animals. Even up to 24 h post-dose, the AUC_0-24h is significantly decreased to 50.7 % of the plasma value in untreated animals and this significant effect is prolonged up to 60 h post-dose.

Conclusions

This study shows that treatment with polyglucosamine (formoline L112) reduces (as judged by C_max & AUC) and delays (as judged by T_max) fat absorption from the gastrointestinal tract into the systemic circulation and limits peak exposure to free fatty acids which may contribute to a more beneficial condition in overweight humans.

Excipient foods: designing food matrices that improve the oral bioavailability of pharmaceuticals and nutraceuticals

The oral bioavailability of many lipophilic bioactive agents (pharmaceuticals and nutraceuticals) is limited due to various physicochemical and physiological processes. Excipient foods can be designed to improve the oral bioavailability of these bioactive agents.