Prebiotic Potential of Chitosans Prebiotic

¶ … Prebiotic Potential of Chitosans

Prebiotic Potential Of Chitosan

"The favourable properties like biocompatibility, biodegradability, pH sensitiveness, mucoadhesiveness, etc.

has enabled these polymers to become the choice of the pharmacologists as oral delivery matrices for proteins"

(George & Abraham, 2006, Abstract section).).

In the study, "Polyionic hydrocolloids for the intestinal delivery of protein drugs: Alginate and chitosan- a review," M. George and T.E. Abraham (2006) discuss the contemporary challenge in the design of oral delivery of peptide or protein drugs. Consequently, as the majority of "the synthetic polymers are immunogenic and the incorporation of proteins in to these polymers require harsh environment which may denature and inactivate the desired protein" George and Abraham (2006, Abstract), pH sensitive hydrogels such as alginate and chitosan have begun to attract increasing attention. Due to its hydrophilic nature and simple solubility in acidic medium, chitosan possesses only limited ability to control the release of encapsulated compound. Simple covalent modifications of the polymer, albeit, may change its physicochemical properties and, in turn, make it suitable for the peroral drug delivery purpose. During this qualitative case study, which investigates the prebiotic potential of chitosan, the researcher examines the following components:

1. Prebiotics

2. Chitosan

3. prebiotic potential of chitosan

The primary research question this study addresses queries: What is the prebiotoc potential of chitosan? The two research sub-questions contributing support to answer the primary research question include?

1. How chitosans are currently utilized?

2. What concerns contribute to challenges for utilizing chitisans in prebiotics?

The hypothesis for this study asserts: When current research resolves current challenges regarding the factors hindering the potential of prebiotics in chitisans, then the efficiency of prebiotics will increase.

Prebiotics

Katherine Zeratsky, R.D., L.D. (2009), the Mayo Clinic, asserts in the journal article,

"Prebiotics: What are they?" that prebiotics constitute nondigestible nutrients certain beneficial bacteria that naturally live in one's intestines use as an energy source. "Prebiotics are sometimes known as fermentable fiber" (Zeratsky, ¶ 1). In contrast, probiotics, consist of the beneficial, or friendly, bacteria themselves. As a food source for probiotics, prebiotics give the probiotic bacteria the opportunity to exert their influence. These friendly bacteria possess a number of health benefits, including digesting to boosting one's immunity. Stress, certain medical conditions, medications, a poor diet, and other factors, however; may decrease the number of healthy bacteria. Eating a diet that includes prebiotics may help restore the friendly bacteria.

Zeratsky (2009) asserts that currently, the role of prebiotics in regard to the treatment of disease proves controversial, which necessitates the need for further studies to determine their potential usefulness. Figure 1 depicts certain conditions that preliminary evidence proposes that prebiotics may have a role in:

Figure 1: Conditions Prebiotics May Help Alleviate (adapted from Zeratsky, 2009, ¶ 3).

Zeratsky (2009) explains that prebiotics occur naturally in various foods, particularly in high-fiber foods, including certain fruits, grains and vegetables. The primary food sources of prebiotics include: "Artichokes, Bananas, Barley, Berries, Chicory, Dairy products, Flax, Garlic Greens, such as dandelion greens, chard and kale, Honey, Leeks, Legumes, Onions and Wheat and whole grains, such as oatmeal" (Zeratsky, ¶ 4). Manufacturers also add prebiotics to numerous dietary supplements, as well as to some processed foods, including drink mixes and meal-replacement bars, and yogurt. Not all products with naturally-occurring prebiotics, however, are labeled as such. Prebiotic supplements may be taken as capsules or tablets that one swallows or chews or may be sprinkled on one's food, and/or stirred into beverages.

No specific guidelines exist regarding how many grams of prebiotics one needs to consume. Some studies suggest that one should consume from 3 to 8 grams a day to obtain the full benefits of prebiotics, however, in some instances, use of prebiotics may stimulate intestinal gas. Zeratsky (2009) recommends that one, checks with his/her doctor before taking any dietary or herbal supplements to ensure they will be safe for his/her situation.

The article, "Prebiotics: A Consumer Guide for Making Smart Choices," (N.D.) asserts that the three criteria are currently required for a prebiotic effect:

Resistance of the prebiotic to degradation by stomach acid, mammalian enzymes or hydrolysis;

Fermentation (breakdown, metabolism) of the prebiotic by intestinal microbes; and Selective stimulation of the growth and/or activity of positive microorganisms in the gut. ( Prebiotics: A Consumer…, N.d., ¶ 2).

Good prebiotics remain stable under heat and also when dried. They may be stored at room temperature for months. "A daily dose of 5-8g/d fructooligosaccharides (FOS) or galactooligosaccharides (GOS) has a prebiotic effect in adults. & #8230;Both fibre and prebiotics are typically non-digestible carbohydrates, and both are typically fermented by gut bacteria" Prebiotics: A Consumer…, N.d., ¶ ¶ 3 & 6). A prebiotic differs from fibre, however, only beneficial members of the gut microbial community selectively use it in the gut. Although a number of manufacturers refer to prebiotics as fibre, as fibre constitutes a more familiar term for consumers, prebiotics are historically more closely linked to the probiotic concept than to the fibre one.

Chitosan

Becca Goodyear (2009), affiliate of Vanderbilt University, defines chitosan in the article, "Chitosan." Chitosan, "a modified carbohydrate polymer derived from the chitin component of the shells of crustacean, such as crab, shrimp, and cuttlefish & #8230;is deproteinized, demineralized and de-acetylated. & #8230;Chitosan is composed of a NH4+ (ammonium) group attached to a polyglucosamine chain" (Goodyear, 2009, p. 1). Because chitosan is a dietary fiber, the digestive enzymes of a person cannot digest it.

Chitin, a primary by-product of the crabbing and shrimp canning industry also depicts the main source of surface pollution in coastal areas. Since the 1990s, studies on chitin and chitosan have expanded to seek value-added uses of these polysaccharides that reveal exceptional biological properties. Figure 2 depicts these particular properties.

Figure 2: Excellent Biological Properties of Polysaccharides (adapted from Argin, 2007, p. 9).

Chitin, Argin (2007) explains, constitutes the second most prevalent natural polysaccharide; present in crustacea, insects and yeasts. Alkaline deacetylation of chitin produces chitosan, poly-?-(1-4)-D-glucosamine, the only natural cationic polysaccharide. Chitin and chitosan demonstrate a molecular weight of ranges "between several hundred thousands to 1 million Dalton" (Argin, 2007, p. 9). As the degree of acetylation (DA) affects chitosan's biodegradation capability, solubility, gelling and its reactivity, DA constitutes a significant property of chitosan molecules. "The unique properties of chitosan arise from its amino groups that carry positive charges at pH values below 6.5, enabling it to bind to negatively charged materials such as enzymes, cells, polysaccharides, nucleic acids, hair and skin" (Argin, 2007, p. 9). Chitosan, a linear polysaccharide, possess both reactive amino groups and hydroxyl groups that may be utilized to modify its physical and solution properties

Chitin and chitosan, currently being extensively utilized in the pharmaceutical industry, may be found in artificial skin, cosmetics, contact lenses and wound dressing. They are also routinely used in manufacturing animal feed, chromatography, dietary supplements, paper, photography components, solid state batteries, and for waste water treatment.

Chitosan, Argin (2007) further explains is not soluble at alkaline and neutral pH, however, it is soluble in inorganic and organic acids, "such as hydrochloric acid, acetic acid, lactic acid and glutamic acid. Water soluble chitosan can be formed when hydrogen-bond formation is prevented by partial re-acetylation of chitosan molecules by several means" (Argin, 2007, p. 10). In addition, significant research has been invested to investigate the use of chitosan as a drug delivery vehicle, particularly for the treatment of ulcerative colitis, Crohn's disease, and other colon diseases. Research also includes the exploration of chitosan as a dietary supplement to lower cholesterol and to help control weight. Generally, chitosan for human oral administration is accepted as safe and approved for food use in Italy, Norway, and Japan. "In the U.S., chitosan…[has not yet been] approved as a food additive by the U.S. Food and Drug Administration (FDA)" (Argin, 2007, p. 10). In 1985, however, the Association of American Feed Control Officials (AAFCO) approved chitosan for its use in animal feed; provided the level does not exceed 0.1% of the feed. Figure 3 depicts the molecular structure of chitosan; while Figure 3 portrays the chemical structure of chitosan.

Figure 3: Molecular Structure of Chitosan (Baynes-Clarke & Taylor, 2001, Molecular Structure section…).

Figure 4: Chemical Structure of Chitosan (Baynes-Clarke & Taylor, 2001, Molecular Structure section…).

Chitin-Chitosan in Clinical Practice

In the publication, "Chitin-Chitosan: The power of crab shell," Stephen Levine, (2007), Biochemist from UC Berkeley, reports that Dr. Akira Matsunaga (2007), the first doctor in Japan to use chitin-chitosan in clinical practice, explains the differences in processing chitin and chitosan:

Chitin-chitosan (CC) is a mixture of chitin and chitosan. The chitin, the component of the crab shell, becomes chitosan upon enzymatic treatment. Chitin may be "the primordial form" of some of the first living things on earth, existing much earlier than dinosaurs. In order to extract only the chitin from crab shell, a chemical process is used consisting of 5% hydrochloric acid, which removes the calcium, and 5% sodium hydroxide, which dissolves the protein. If the chitin is deacetylated (by treating it with 45% sodium hydroxide (or caustic sodium) at a high temperature), chitosan is produced (Levine, 2007, p. 1).

This treatment, albeit, does not produce 100% chitosan, but basically produces a mixture of 10-15% chitin plus 85-90% pure chitosan, called "pure CC." In the U.S., chitosan constitutes a mixture of approximately7% chitin plus approximately 93% chitosan. Outside of cost-effectiveness, the biological effects of chitin produced from each source appears identical. "Chitosan oligosaccharides (CO) takes chitosan a big step further," Matsunaga (2007 explains. "When CC is ingested, a small amount of it is broken down into very small molecular particles by the enzymes of the body, thus producing CO. CO can also be manufactured by using an enzymatic process" (Matsunaga, as cited in Levine, p. 1). The body more readily absorbs CO, although CO contains less fiber than regular CC.

In Case History 1: Low Pulmonary (Lung) Function, Matsunaga (Levine, 2007) treats his first patient, also his father, with the administration of CC. Previous treatments had yielded no results for Matsunaga's father who suffered from diminished lung function, which resulted from lung surgery to treat tuberculosis 30 years previously. Dependent on an oxygen tank, Matsunnaga's father could only walk a few steps each day. "After taking only two capsules of chitosan twice per day (a total of 120 mg) for one week, Matsunaga's father was able to walk around the house without his oxygen tank" (Levine,, p. 1). By the tenth day, Matsunaga's father could leave the house. He quit taking medications, yet he did not experience any adverse effects; living three years of additional improved health and life quality before he died at age 81.

Matsunaga (Levine, 2007) describes Case History 2, relating details of a patient with skin cancer. Other doctors had recommended that the ear lobe of the 75-year-old man, with skin cancer on his ear, had to be removed. Once more, following a myriad of ineffective treatments, Matsunaga prescribed the identical dosage he had given to his father; 2 caps of chitosan 2x per day. The cancer reportedly started to shrink within one week. Following four more days of treatment with chitosan, the cancer completely disappeared. As a result of the impressive results, Matsunaga began to implemtn the use of chitosan on a wider scale in his clinical practice; carefully documenting detail. Typically, "he found that weak patients became stronger, and healthy patients became healthier; that often symptoms resistant to medications were alleviated; common daily complaints such as constipation, shoulder stiffness, low back pain, etc., disappeared" (Levine, p. 1). Patients generally were able to reduce their medication dosages by an average of 30%; lessening side effects experienced from medication. The quality of life for those terminally ill patients treated with chitosan also significantly improved, Matsunaga reports.

From his studies, Matsunaga (Levine, 2007) found that chitosan proved effective in treating a wide variety of health conditions. These conditions included: "Circulatory and heart diseases, dermatoligical diseases (atopic dermatitis, etc.), opthamological (eye) conditions, ENT (ear, nose & throat) conditions, hemorrhoids, and a multitude of problems affecting all organs of the body" (p.1). In 1982, through the Ministry of Agriculture and Fishery, in response to the as massive piles of unused crab shells accumulating at numerous crab meat processing plants, the Japanese government initiated a ten-year project to develop ways to utilize unused biomass. Following the funding of a six billion dollar grant by the Ministry of Education for "A New Extension of Basic and Clinical Researchers on Chitin-Chitosan and Their Enzymes," 13 universities began research relating to chitosan. Findings from some the research during this time included:

Animal Studies

Cholesterol & Liver Health: Findings revealed that "CC lowered cholesterol and neutral fats, and prevented liver dysfunction." The livers of the group not treated with CC appeared inflamed and fatty livers. The livers of the chitosan group, albeit, appeared completely normal. Findings from a number of animal studies revealed that CC absorbs LDLcholesterol and transports it out of the body through the intestines. It also raises HDL cholesterol (Levine,, 2007, p. 2).

Cancer

CC reportedly possess anticancer action, and prevents metastases of cancer cells; studies reported that macrophage and natural killer cells were strengthened. (Levine, 2007, p. 2).

Blood Pressure

As chitosan inhibits ACE activity, it removes chlorine, and in turn, no hypertension results (Levine,, 2007, p. 2).

Table 1 depicts a summary of several abstracts reflecting extensive research on chitosan-oligosaccharide, along with numerous potential benefits for health:

Table 1: Comparison of Chiosan-oligosaccharide Studies (adapted from Levine,, 2007, p. 2).

Author(s), Date

Title of Study

Purpose/Method

Results of Study

H.W. Lee, Y.S. Park, J.S. Jung & W.S. Shin;

Chitosan oligosaccharides, dp 2-8, have prebiotic effect on the Bifidobacterium bifidium and Lacto-bacillus sp.

To investigate the prebiotic potential of chitosan oligosaccharide (COS), the effect of COS on bacterial growth was studied... The effects of COS on the growth of bifidobacteria and lactic acid bacteria were compared with those of fructooligosaccharide (FOS).

Chitosan oligosaccharide can promote the growth of friendly bifidobacteria and lactobacillus. Unlike fructooligo saccharides (FOS), which promote the growth of only three probiotic strains, chitosan oligosaccharide supports almost all bifido- and lacto-bacillus species.

Y. Yan, L. Wanshun, H. Baoqin, L. Bing, & F. Chenwei; May 2006.

Protective effects of chitosan oligosaccharide and its derivatives against carbon tetrachloride-induced liver damage in mice.

To examine the protective effects of chitosan oligosaccharide (COS), dglucosamine (GlcNH (2)) and N-acetyl-d-glucosamine (GlcNAc) on carbon tetrachloride (CCl (4))-induced hepatotoxicity and the possible mechanisms that involved were investigated in male ICR mice.

Chitosan oligosaccharide has been shown to protect the liver from damage by carbon tetrachloride in mice.

H.J. Yoon, H.S. Park, H.S. Bom, Y.B. Roh, J.S. Kim & Y.H. Kim; September 2005.

Chitosan oligosaccharide inhibits 203HgCl2-induced genotoxicity in mice: micronuclei occurrence and chromosomal aberration.

To investigate the effect of chitosan oligosaccharide on mercury- induced chromosome aberration; mice in each condition were supplied with 203HgCl2 and chitosan oligosaccharide ad libitum.

Chitosan oligosaccharide has been shown to protect against mercury toxicity in mice.

H.W. Lee, Y.S. Park, J.W. Choi, S.Y. Yi & W.S. Shin; August 2003.

Antidiabetic effects of chitosan oligosaccharides in neonatal streptozotocin-induced noninsulin-dependent diabetes mellitus in rats.

To examine the antidiabetic effect of chitosan oligosaccharide (COS) in neonatal streptozotocin (STZ)-induced noninsulin- dependent diabetes mellitus rats.

In non-insulin-dependent diabetic rats, chitosan oligosaccharide had an anti-diabetic effect.

The fasting glucose level was reduced by about 19% in diabetic rats after treatment with 0.3% COS. Glucose tolerance was lower in the diabetic group compared with the normal group

J.S. Moon, H.K Kim, H.C. Koo, Y.S. Joo, H.M. Nam, Y.H. Park & M.I. Kang; March 2007.

The antibacterial and immunostimulative effect of chitosan-oligosaccharides against infection by Staphylococcus aureus isolated from bovine mastitis.

Based on previous study, this study evaluates the in vivo cure efficacy of chitosan on bovine mastitis, a more water-soluble chitosanoligosaccharide (OCHT) with a high degree of deacetylation and low molecular weight was prepared to obtain high antibiotic efficacy. The growth of Staphylococcus aureus isolated from bovine mastitis was inhibited within 10 min of treatment with OCHT in concentrations ranging from 0.0001 to 0.5% in the mice for this study.

Chitosan oligosaccharide has been shown to have antibacterial and immunostimulative effects against infection by Staphylococcus aureus.

As chitosan's molecular weight consists of several hundred thousands to several millions, Matsunaga explains, chitosan binds well to heavy metals and efficiently excretes the metal particles from the body. When chitosan binds to them, the heavy metals cannot remain ionized. They become enclosed within the chitosan molecules. Originally, pure chitosan is white or off-white, however, when excreted bound to a heavy metal, chitosan converts to the color of that metal. Copper in chitosan, for example, "comes out as dark blue, nickel comes out as light blue, cobalt -- pink, iron -- light yellowish brown, chrome -- brown, etc. (Levine, 2007, p. 3).

Matsunaga suggests the ability of chitosan to bond to metal could prove particularly helpful to individuals who consume a diet high in fish diet, such as the Japanese, as they may be ingesting high amounts of mercury. Chitosans' heavy metal binding benefits, however, extend beyond the human body. As chitosan, a natural material is not toxic, and massive amounts of it do not negatively affect the environment, it may also be utilized to treat heavy metals that waste product, produced by industry, contain (Levine, 2007).

Even though chitin is a safe, natural substance and not manufactured with any synthetic chemicals, Matsunaga (Levine, 2007) stresses that it proves critical to note that CC and/or CO may be contraindicated for individuals with shellfish allergies. Results have been repeatedly consistent with reports from other international sources that chitin is not toxic; with the Japan Precision Chemical Corporation conducting toxicity tests on CC; consequently confirming that it is safe. A number of studies completed on CC include, albeit, but are not limited to the following:

Heat source reflection, intracutaneous injection, skin sensitivity testing, systemic anaphylaxis test, eye conjunctiva and corneal test, hemolysis test, test of depressor substance, subcutaneous and endosteal implant test, mutagenic test, dominant lethal test, etc. (Levine, 2007, p. 3).

Figure 5 presents an abbreviated timeline of expansive information presented in Figures 5 and Figure 6.

folk remedy

4000 Years Ago

14th -- 17th Century

16th Century

1950

1965

1977

1992

1993

Current

Figure 5: Abbrieviated Chitin-Chitosan Timeline (adapted from Levine, 2007, p. 3).

Figure 6: Chitin-Chitosan Timeline through 1987 (adapted from Levine, 2007, p. 3).

Figure 7: Chitin-Chitosan Timeline 1982 through 1987 (adapted from Levine, 2007, p. 3).

Potential Applications

In the Doctoral Thesis, "Adsorption of biopolymers and their layer-by-layer assemblies on hydrophilic surfaces, Maria Lundin (2009) discusses a number of potential applications for the multilayer-film coatings which may be prepared on both planar substrates and on colloidal particles. Lundin explains: "A wide range of potential applications has been suggested for the multilayer films in such diverse areas as drug delivery systems, micropatterning, biomedical applications, food applications, and paper making" (p. 12). From the latter, Lundin further purports:

…Hollow capsules can be prepared by dissolution of the particle core after the multilayer-film preparation.44 the hollow capsules can then be loaded with pharmaceuticals and by choosing the right polymer pair, for the coating, it is possible to control the release rate from these capsules. On planar substrates there have been much research on antibacterial coatings for surfaces in contact with body fluids both in-situ and ex-situ.

The selection of suitable polymers together with the possibility of incorporating any type of charged molecule into the film enables the formation of surfaces that are cell/protein attractive or repellent.46 in packing applications for example of food, both oxygen and water barriers are required in order to prevent oxidation of food products during transportation. A commercial product on the market is the fruit bags (Yasa-sheet) that keep vegetables and fruits fresh for weeks by reducing the emission of ethylene gas. These fruit bags are prepared from LbL deposition of chitosan and an enzyme extracted from bamboo. (Lundin, 2009, p. 12)

Figure 8 relates the result from the use of the Yasa-sheets S. Shiratori (Japan) invented to extend the freshness of fruits. Lundin (2009) adapted the figure from the Web page: http://www.nasuden.co.jp/yasa.htm, which the researcher further adapted.

Figure 8: Result of Using the Yasa-sheets (adapted from Lundin, 2009, p. 12).

Anal and Singh (2007) explain that due to its unique polymeric cationic character, good biocompatibility, non-toxicity and biodegradability, the biopolymer chitosan, the N-deacetylated product of the polysaccharide chitin, currently merits increasing attention in the food and pharmaceutical field. According to Anal and Singh (2007):

Chitosan can be isolated from crustacean shells, insect cuticles and the membranes of fungi. The properties of chitosan vary with its source. The terms chitin and chitosan refer not to specific compounds but to two types of copolymers, containing the two monomer residues anhydro-N-acetyl-D-glucosamine and anhydro-D-glucosamine, respectively. Chitin is a polymer of b-(1-4)-2-acetamido-2- deoxy-D-glucopyranose and is one of the most abundant organic materials on earth and second to cellulose and murein, which is the main structural polymer of the bacterial cell wall. In order to achieve sufficient stability, chitosan gel beads and microspheres can be ionically cross-linked with polyphosphates and sodium alginate. (Anal & Singh, 2007, p. 247)

Anal and Singh (2007) explain that contemporary, sophisticated shell materials and technologies contribute to a number of diverse functionalities that microencapsulation may currently achieve. Various types of triggers may prompt the release of the encapsulated ingredients. These include enzymatic activity, mechanical stress, osmotic force, pH changes, temperature, time, etc. Encapsulated probiotic bacteria may be used in numerous fermented dairy products, as noted earlier in this stud. The encapsulated form protects probiotics from bacteriophage and freezing, gastric solutions and other harsh environments, as a result, encapsulation aids the manufacture of fermented dairy products where the bacteria have consistent characteristics and higher stability during storage. These products also have higher productivity than nonencapsulated bacteria (Anal & Singh, 2007).

A critical challenge for cell encapsulation consists of the massive size of microbial cells (typically 1e4 mm) or particles of freeze-dried culture (more than 100 mm). This characteristic limits cell loading for small capsules or, when large size capsules are produced, can negatively affect the textural and sensorial properties of food products in which they are added" (Anal & Singh, 2007, p. 248). In the majority of cases, researchers favor gel entrapment using natural biopolymers, such as calcium alginate, carrageenan, gellan gum, and chitosan. Despite the potential projected on a laboratory scale, nevertheless the developed technologies for producing gel beads still present critical challenges for massive-scale production of food-grade microencapsulated microorganisms. (Anal & Singh, 2007, p. 248).

In the article, Rheology of chitin, Philip Baynes-Clarke and Richard Taylor (2001), Loughborough University, relate the following applications for use of chitin and chitosan:

1. Agricultural: Chitin and chitosan have anti-fungal properties that can be used to protect seeds from soil fungi by coating the seeds with chitin or chitosan.

Chitin and chitosan can also be used as an antinematode agent in soil and both are biodegradable.

2. Cosmetics: Chitin and chitosan are non-toxic and non-allergenic which means that the body won't reject them as foreign invaders; hence they can be used in the production of emulsifiers, anti-static agents and emollients to extend the cosmetic product shelf life.

3. Medicinal: Chitin and chitosan have anti-bacterial and anti-viral properties that have led to them being used as wound dressings, surgical sutures and in cataract surgery and Periodontal disease and burns treatment.

4. Food Industry: Chitin can be used to recover proteins from food processing wastes to be used in animal food production. Mycrocrystalline Chitin (MCC)

has been used as a thickening/gelling agent in the binding, stabilising and texturing of food. (Baynes-Clarke & Taylor, 2001, Applications of chitin section).

Baynes-Clarke & Taylor (2001) recommend that following be observed to optimize the dissolution of chitin the following should be observed:

1. Reduce the particle size of the chitin to

2. Allow the solution (

hours at room temperature

3. Do not use homogenisation to dissolve the swollen chitin that will remain.

Instead, filter the sample and perform suitable calculations on filter paper weights, etc. To obtain quantity of chitin in solution

4. Avoid application of heat at any stage of analysis as chitin becomes denatured if exposed to temperatures as low as 40°C for prolonged periods. (Baynes

Clarke & Taylor, 2001, Conclusion section)

Due to its hydrophilic nature and easy solubility in acidic medium, George and Abraham (2006) purport that chitosan only possesses a limited ability to control the release of encapsulated compound. Conducting basic covalent modifications of the polymer, albeit, as noted at the start of this study, can change its physicochemical properties so that it may become suitable for the peroral drug delivery purpose. Also, as noted at the start of this study, the favorable properties of chitosan, such as it is "biocompatibility, biodegradability, pH sensitiveness, mucoadhesiveness, etc. has enabled these polymers to become the choice of the pharmacologists as oral delivery matrices for proteins" (George & Abraham, 2006, Abstract). Delivering probiotics through the oral route, the most preferred route, although currently a challenge, may become more of a routine reality with chitosan.

Goodyear (2009) explains that companies selling chitosan claim that among a myriad of other things, can help an individual lose weight, reduce his/her high cholesterol, and his/her high blood pressure. Chitosan reportedly increases the absorption of calcium in a body, while it also eliminates heartburn, "alleviates the symptoms of IBS, and kills Candida, yeast in the colon that causes cancer. Companies selling chitosan claim that some patients have lost 8% of their body fat in 4 weeks" (Goodyear, 2009, p. 2). The companies making chitosan also contend that it reduces an individual's blood cholesterol by 66%, and has 55% greater fat absorption than other fibers. It also reportedly lowers the LDL (bad) cholesterol, yet simultaneously increases the HDL cholesterol; also decreasing the risk of colon cancer. Chitosan has been reported to slowing down the individual's increase in blood glucose, consequently controlling hunger. According to the Grassroots Natural Products, chitosan drastically attracts fat; reportedly absorbing six to ten times its own weight in fat (Goodyear, 2009, p. 2).

Edward R. Farnworth (2008) contends in the book, Handbook of fermented functional foods, that ice cream, frozen yogurts, and frozen desserts possess potential as carriers of probiotic organisms. What must be considered, however, is the effect freeze stress may impact on viability during manufacture and extended storage. In some instances, more protection is needed to increase the survival rate of cells during freezing (Farnworth, 2008().

In the book, Edible Films and Coatings for Food Application, Milda E. Embuscado (2009) asserts that by decreasing respiration rates, inhibiting microbial development and delaying ripening, the chitosan films or coatings may increase shelf life and preserve quality of fruits and vegetables. Embuscado explains that "the concept of probiotics evolved from the hypothesis that the healthy life of Bulgarian peasants resulted from their consumption of fermented milk products. In the last century, probiotic bacteria most commonly studied include members of the genera Lactobacillus and Bifidobacterium"(Embuscado, 2009, p. 328). Contemporary increasing, global interest in probiotics set the stage to expand marketing of these products.

Stephen Daniells (2007), feature writer, reports in the journal publication, "Chitosan microcapsules get bioavailability boost," that although chitosan previously had been proposed as an effective encapsulating ingredient, its improved stability to thermal processing, lipid oxidation, and freezing and thawing, the actual bioavailability of the encapsulated lipid was not clear. Daniells (2007) concludes that previous studies report that chitosan supplements reduce cholesterol levels in both animals and humans.

In the journal publication, "Chitosan drug binding by ionic interaction," Yaowalak Boonsongrit and Ampol Mitrevej, both with the Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand and Bernd W. Mueller (2005), Department of Pharmaceutics and Biopharmaceutics, Christian-Albrechts-University, Kiel, Germany, use three model drugs (insulin, diclofenac sodium, and salicylic acid) with different pI or pKa to prepare drug-chitosan micro/nanoparticles by ionic interaction.

Physicochemical properties and entrapment efficiencies were determined. The amount of drug entrapped in the formulation influences zeta potential and surface charge of the micro/nanoparticles. A high entrapment efficiency of the micro/nanoparticles could be obtained by careful control of formulation pH. The maximum entrapment efficiency did not occur in the highest ionization range of the model drugs. The high burst release of drugs from chitosan micro/nanoparticles was observed regardless of the pH of dissolution media. It can be concluded that the ionic interaction between drug and chitosan is low and too weak to control the drug release. (Boonsongrit, Mitrevej & Mueller, 2005, p. 267)