Patent Application
20080306020
The present invention relates to a skin-protecting alkalinity-controlling composition as well as the use of a composition comprising at least one carboxylic acid polysaccharide for skin protection and/or alkalinity control.
Pectin is a complex polysaccharide associated with plant cell walls. It consists of an alpha 1-4 linked polygalacturonic acid backbone intervened by rhamnose residues and modified with neutral sugar side chains and non-sugar components such as acetyl, methyl, and ferulic acid groups.
The neutral sugar side chains, which include arabinan and arabinogalactans, are attached to the rhamnose residues in the backbone. The rhamnose residues tend to cluster together on the backbone. So, with the side chains attached, this region is referred to as the hairy region and the rest of the backbone is hence named the smooth region.
In U.S. Pat. No. 5,929,051, Ni, et al. pectin is described as a plant cell wall component. The cell wall is divided into three layers, middle lamella, primary, and secondary cell wall. The middle lamella is the richest in pectin. Pectins are produced and deposited during cell wall growth. Pectins are particularly abundant in soft plant tissues under conditions of fast growth and high moisture content. In cell walls, pectins are present in the form of a calcium complex. The involvement of calcium cross-linking is substantiated by the fact that chelating agents facilitate the release of pectin from cell walls as disclosed by Nanji (U.S. Pat. No. 1,634,879) and Maclay (U.S. Pat. No. 2,375,376).
According to Dumitriu, S.: Polysaccharides, Structural diversity and functional versatility, Marcel Dekker, Inc., New York, 1998, 416-419, pectin is used in a range of food products.
Historically, pectin has mainly been used as a gelling agent for jam or similar, fruit-containing, or fruit-flavoured, sugar-rich systems. Examples are traditional jams, jams with reduced sugar content, clear jellies, fruit-flavoured confectionery gels, non-fruit-flavoured confectionery gels, heat-reversible glazing for the bakery industry, heat-resistant jams for the bakery industry, ripples for use in ice cream, and fruit preparations for yoghurt.
A substantial portion of pectin is used today for stabilization of low-pH milk drinks, including fermented drinks and mixtures of fruit juice and milk.
The galacturonic acid residues in pectin are partly esterified and present as the methyl ester. The degree of esterification is defined as the percentage of carboxyl groups esterified. Pectin with a degree of esterification (“DE”) above 50% is named high methyl ester (“HM”) pectin or high ester pectin and one with a DE lower than 50% is referred to as low methyl ester (“LM”) pectin or low ester pectin. Most pectins found in plant material such as fruits, vegetables and eelgrass are HM pectins.
Pectins are soluble in water and insoluble in most organic solvents. Pectins with a very low level of methyl-esterification and pectic acids are for practical purposes only soluble as the potassium or sodium salts.
Pectins are most stable at pH 3-4. Below pH 3, methoxyl and acetyl groups and neutral sugar side chains are removed. At elevated temperatures, these reactions are accelerated and cleavage of glycosidic bonds in the galacturonan backbone occurs. Under neutral and alkaline conditions, methyl ester groups are saponified and the polygalacturonan backbone breaks through beta-elimination-cleavage of glycosidic bonds at the non-reducing ends of methoxylated galacturonic acid residues. These reactions also proceed faster with increasing temperature. Pectic acids and LM pectins are resistant to neutral and alkaline conditions since there are no or only limited numbers of methyl ester groups.
Pectin is a weak acid, and is less soluble at low pH than at high pH. Thus, by changing the pH of the pectin during manufacture thereof, a pectin having lower or higher solubility is provided. The pH is typically increased through the use of bases such as alkali metal hydroxides or alkali metal carbonates, but other bases are equally useable. For instance, by using sodium carbonate, sodium pectinate is formed and the higher the dosage of sodium carbonate and, thus, the higher the pH, the more of the carboxylic acids are transformed to their sodium salts.
However, at higher pH the pectin starts to de-esterify during pH-adjustment, handling and storage. Thus the pH should be maintained at a level at or below pH 6.
In some cases, pectin as manufactured is esterified in a block-wise fashion. WO 2004020472 describes this phenomenon as the block-wise de-esterification takes place in the raw material used for making pectin, and the disclosure relates to a method for eliminating this block-wise de-esterification.
WO 8912648 discloses a method for transforming block-wise de-esterified pectin into pectin with a random distribution of ester groups. The method involves the use of polygalacturonase, which splits the pectin molecule in those areas of the pectin molecule that are non-esterified. Thus, this method provides a lower molecular weight pectin having a higher degree of esterification than the block-wise esterified starting pectin.
According to Kertesz, Z. I: The Pectic Substances, Interscience Publishers, Inc, New York, 1951, pectic materials occur in all plant tissues. However, apples, beets, flax, grapefruit, lemons, limes, oranges, potatoes, and sunflower are of particular industrial importance. Lately, also the pectin in Aloe Vera has shown industrial utility.
Pectin according to the present invention needs not be extracted from the pectin containing starting material. Such crude pectin preparations are disclosed in U.S. Pat. No. 2,132,065, U.S. Pat. No. 3,982,003, U.S. Pat. No. 4,831,127, WO 9115517, U.S. Pat. No. 5,354,851, U.S. Pat. No. 5,403,612, U.S. Pat. No. 5,567,462, U.S. Pat. No. 5,656,734, and WO 9749734.
Other esterified carboxy acid polymers include, but are not limited to:
According to www.smartskincare.com, sweat is a salty, watery solution produced by sweat glands, numerous microscopic channels opening onto the skin surface. As sebum and sweat mix up on the skin surface, they form a protective layer often referred to as the acid mantle. The skin is mildly acidic. In addition to helping protect skin from “the elements” (s u c h as wind or pollutants), the acid mantle also inhibits the growth of harmful bacteria and fungi. If the acid mantle is disrupted or loses its acidity, the skin becomes more prone to damage and infection. The loss of acid mantle is one of the side effects of washing the skin with soaps or detergents of moderate or high strength.
According to U.S. Pat. No. 5,837,254, fungal infections of the vagina or urinary tract are difficult to eradicate and frequently recur but are rarely life threatening. The normal pH of the genital tract is 4.5 to 5, which is maintained by lactobacillus. The absence of lactobacillus and a normal pH promotes candidiasis as well as the herpes virus, birth control pills, a weak immune system, genetic factors, stress and a host of other factors, which foster the growth of yeast and fungal infections of the genital tract. Candida albicans grows readily in a moist environment at a pH of more than 5.
In U.S. Pat. No. 5,972,321 it is stated that although body odor may be partially due to certain chemicals secreted by sebaceous glands and eccrine sweat glands, major axillary (underarm) foul odor is due to secretions of the apocrine glands, which contain special nutrient materials for microorganisms. The apocrine glands secrete a milky fluid that has a pH range of 5 to 6.5 and initially consists of lipids, proteins and carbohydrates. Although gram-positive bacteria, which thrive on substances found on the moist skin surface, appear to be responsible for the production of malodor, the precise mechanisms of odor production are still unclear.
According to U.S. Pat. No. 4,666,707, bath salt compositions are prepared by incorporating perfume, colorant, plant extract, organic acid and so on into an inorganic salt mixture comprising sodium sulfate, borax, sulfur, sodium chloride, carbonate salt, etc., and are used for the purpose of providing the bath with perfume and/or color, or adequately stimulating the skin to thereby promote the blood circulation, the recovery from fatigue and/or the metabolism. Among such bath salt compositions, there are foaming bath salt compositions comprising a combination of a carbonate salt and an acid, which produces, in the bath, carbon dioxide gas bubbles to thereby cause a relaxing or refreshing sensation and render bathing enjoyable.
According to U.S. Pat. No. 6,589,923 and U.S. Pat. No. 4,335,025, upon washing with soap, a pH of 8-10 is established in the wash liquor. This alkalinity neutralizes the natural acid mantle of the skin (pH 5-6). Although in normal skin this acid mantle is reformed relatively quickly, in sensitive or pre-damaged skin irritations may result. A further disadvantage of soaps is the formation of insoluble lime soaps in hard water. Being alkaline, soap emulsifies the oily layer covering the natural horny layer (stratum corneum) of a person's skin and neutralizes a like-wise natural acid mantle of the epidermis, which has, normally, an acid pH of approximately 5.5-6.5. Failure to readily regenerate the acid and oily part of the epidermis—particularly among older people—often results in dermatological symptoms, such as itching, chapping and cracking of the epidermis, especially in cold weather. Of course, always to be considered is that significant segment of the population, which is allergic to or cannot tolerate conventional soaps in view of a number of reactions (sensitivities) resulting from the use thereof.
According to U.S. Pat. No. 6,551,987, U.S. Pat. No. 6,013,618 and U.S. Pat. No. 5,626,852, pro-fragrances are compounds, which under certain conditions break down to fragrances. For instance, tris(9-decenyl) when exposed to suitable conditions (e.g., exposure to the acid mantle of human skin) breaks down to release a mixture of 9-decenol and 9-decenyl formate, both of which are fragrance raw materials.
In U.S. Pat. No. 6,352,700 it is stated that while products exist that are said to address the problems of skin irritation and inflammation, they inevitably fail to address the short-term impact of various additives on the pH balance of the skin, i.e., the skin's acid mantle. To put this into perspective, one need only to consider conventional facial tissue, toilet tissue, napkin and paper towel products that are used for wiping dry or wet skin. Upon contact with skin, the tissue products transfer some of the chemicals present in the tissue to the skin surface.
According to U.S. Pat. No. 6,150,405 and U.S. Pat. No. 5,667,769, some hair care preparations particularly for treating hair loss, contain hydroxyl scavengers.
According to U.S. Pat. No. 4,761,279, the application of a conventional shaving preparation of high alkalinity is often irritating to the skin.
U.S. Pat. No. 2,253,389 discloses the use of alkali to make pectin, which does not require sugar and acid to form gels. A gel is formed by soluble pectin in a neutral or slightly alkaline aqueous medium in the presence of a metal compound, and it is stressed that the alkalinity must be insufficient to convert pectin to pectate. The resulting gelling agent is particularly useful for substituting gelatine in jellies of water and milk.
GB 541,528 discloses the importance of applying low temperature for demethoxylating pectin. By controlling alkali hydrolysis of pectin at temperatures between 10° C. and the freezing point of the pectin solution, low ester pectin of high setting power and with a low setting temperature can be made. Hydrolysis is performed in an aqueous medium and the hydrolysis is terminated by neutralization. It is disclosed that the hydrolysis is very rapid at pH 12 and very slow at pH 8.5.
U.S. Pat. No. 2,478,170 discloses pectin with 20-30% remaining acid groups, which gel by the addition of calcium ions, with or without sugar. Alkalis are alkali metal hydroxides, ammonium hydroxide, sodium carbonate, organic ammonium bases etc. and the process involves an aqueous solution or extract of pectin being adjusted to temperatures below 35° C. and pH 10-12. When the desired methoxyl content is reached, pH is reduced to 4, and the pectinic acid is isolated.
In “The Pectic Substances”, Interscience Publishers, Inc., New York, 1951, Kertesz describes the effect of bases on pectin. When alkali is added to a pectin solution to an extent, which is higher than the amount needed for neutralizing the pectin, demethoxylation commences. This process consumes the alkali and the pH of the solution soon drops. Kertesz also refers to other findings, which suggest that the consumption of alkali increases as a result of the alkali concentration, or the duration of treatment with alkali, or as the temperature of the reaction is raised. Thus, he suggests that this alkali consumption may be utilized for determining the ester content of pectinic acids.
JP 2001226220 discloses the use of alcohol extracted Citrus junos seed pectin to make a skin lotion composed of said pectin, deep sea layer water and sea water or water. The lotion is characterized by being non-sticky, non-irritant and by having a low pH. Conventionally, pectin is extracted in water, whereas alcohol is known to make pectin insoluble. In addition, the disclosure does not discuss the composition of the pectin.
WO 02/14374 discloses the use of hydrocolloids as thickening or emulsifying agents for a variety of products, such as foodstuffs, pharmaceutical compositions, personal care products and beverages.
WO 04/005352 discloses the use of amidated pectins, such as in crèmes, lotions and household products.
U.S. Pat. No. 6,509,311 discloses a gel system comprising propylene glycol alginate as a gelling agent, as a water binder, as an emulsifier and as a stabiliser.
A need for a composition remains, which is capable of providing buffering, thus avoiding a major increase in the pH of an aqueous system and/or useable for reducing the pH of aqueous systems, in which alkalinity is formed as a result of chemical and/or biological reactions, or as a result of alkalinity being imposed on the aqueous system by the environment. In particular, there is a need for a composition, which will protect the acid mantle, and there is a need for incorporating such a composition in articles, which are in contact with the skin, either human skin or animal skin.
The present invention thus relates to a skin-protecting alkalinity-controlling composition comprising one or more carboxylic acid polysaccharides wherein at least one of said carboxylic acid polysaccharide(s) is a high DE carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 70% to about 100%, more preferably from about 80% to about 100%.
The present invention furthermore relates to a skin-protecting alkalinity-controlling composition comprising a mixture of at least one high DE carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 70% to about 100%, more preferably from about 80% to about 100%, and at least one low DE carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 5 to about 70%, more preferably from about 5% to about 40%, and most preferably from about 10% to about 35%.
The present invention furthermore relates to the use of at least one carboxylic acid polysaccharide for skin protection and/or alkalinity control.
The invention is disclosed in more detail in the following by means of the accompanying drawings and exemplary embodiments of preferred embodiments of the invention.
The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
The skin-protecting alkalinity-controlling composition according to the invention comprises one or more high DE carboxylic acid polysaccharides selected from the group comprising pectin esters, esterified cellulose ethers, esterified hydroxyethylcellulose, esterified carboxymethylcellulose, esterified guar gum, esterified cationic guar gum, esterified hydroxypropyl guar gum, starch esters, and polymerized sugar esters.
A high DE carboxylic acid polysaccharide provides for a rapid pH-drop due to the low amount of free carboxylic acid groups present. Thus, if a rapid pH-drop is needed, a high DE carboxylic acid polysaccharide should be used. This fact can be utilized in a range of products intended to be applied to the skin of humans or animals. Uses include but are not limited to lotions, creams, foundations, face masks, hair care products, genital lotions, deodorants, ostomy products, feminine hygiene products, laundry products, bath salt products, soap products, fragrance products, lotionized tissue products, and shaving products. Further, such pectin can be used in similar products to treat animals.
In a preferred embodiment according to the invention, said high DE carboxylic acid polysaccharide is a pectin ester, preferably a pectin ester of aliphatic, arylaliphatic, cycloaliphatic or heterocyclic alcohols, more preferably an ester of methanol, ethanol, propanol or isopropanol, and most preferably an ester of methanol.
The advantage of using methanol esters of pectin is the natural occurrence of such ester. However, without being bound by theory, methyl esters of pectin are more prone to liberate the alcohol part thereof during de-esterification. Esters of pectin with higher alcohols are not as prone to alkaline de-esterification.
In a still more preferred embodiment of the invention, said pectin is of a molecular weight in the range from about 5,000 to about 140,000, preferably in the range from about 10,000 to about 125,000, most preferably in the range from about 10,000 to about 40,000. As demonstrated in example 1 below, the molecular weight of pectin has no influence on the alkali consumption or on the pH drop encountered. However, by adjusting the molecular weight of the pectin it is possible to adjust the amount of pectin, which may be dissolved or suspended in a final product. Thus, as disclosed in more detail in example 11, a lower molecular weight pectin is easier to dissolve and the viscosity of the resulting pectin-containing solution is lower than in a corresponding higher molecular weight-containing pectin. This fact can be utilized to obtain a relatively highly concentrated pectin-solution having suitably low viscosity, e.g. for use in fabric-treating products. The pectin having a molecular weight below about 40,000 can be made at concentrations above about 10% without causing unacceptable high viscosity. Such pectin could be manufactured and marketed as a concentrated solution with a pectin concentration in excess of 10%. Alternatively, the possibility of making such pectin solution in concentrations above about 10% makes spray-drying of such solutions economically feasible.
The degree of esterification indicates the average DE of any given polysaccharide. By controlling the distribution of ester groups along the polysaccharide chain to obtain either a random or a block-wise distribution of ester groups, it is possible to obtain a locally higher or lower DE polysaccharide. As demonstrated in example 3, the alkali consumption of a pectin having a block-wise ester group distribution is the same as the alkali consumption of a corresponding pectin having a random ester group distribution. However, the pH-drop of the two pectins is considerably larger for the block-wise esterified pectin, presumably because such pectin will act as a pectin with a higher average DE. Thus, by treating a block-wise esterified pectin with a polygalacturarase, which splits the pectin at non-esterified sites, a lower molecular weight pectin may be obtained having an increased DE.
In an alternative embodiment of the composition according to the invention, the ester groups of the polysaccharide thereof are thus distributed in a block-wise fashion.
In another embodiment of the composition according to the invention, the ester groups of the polysaccharide are distributed in a random fashion.
In another preferred embodiment according to the invention, the skin-protecting alkalinity controlling composition comprises a mixture of at least one high DE-carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 70% to about 100%, more preferably from about 80% to about 100%, and at least one low DE-carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 5 to about 70%, more preferably from about 5 to about 40%, most preferably from 10 to about 35%.
A carboxylic acid polysaccharide having a relatively low DE provides for a large alkali consumption capacity or buffer capacity.
An advantage of a higher buffer capacity is the ability of the pectin to neutralize an initial high concentration of alkali. This is an advantage particularly when fabrics are insufficiently depleted for alkaline washing powder. Thus, by combining a low DE and a high DE carboxylic acid polysaccharide, an initial alkali consumption buffering can be obtained succeeded by a pH-reduction.
In a preferred embodiment according to the invention, any of said high DE carboxylic acid polysaccharides and said low DE carboxylic acid polysaccharides is selected from the group comprising pectin esters, alginic acid esters, esterified cellulose ethers, esterified hydroxyethylcellulose, esterified carboxymethylcellulose, esterified guar gum, esterified cationic guar gum, esterified hydrocypropyl guar gum, starch esters, and polymerized sugar esters.
In a particular embodiment according to the invention, any of said high DE carboxylic acid polysaccharides and said low DE carboxylic acid polysaccharides is a pectin ester, preferably a pectin ester of aliphatic, arylaliphatic, cycloaliphatic or heterocyclic alcohols, more preferably an ester of methanol, ethanol, propanol or isopropanol, and most preferably an ester of methanol.
In a more particular embodiment according to the invention, any of said high DE carboxylic acid polysaccharides and said low DE carboxylic acid polysaccharides is a pectin having a molecular weight in the range from about 5,000 to about 140,000, preferably in the range from about 10,000 to about 125,000, most preferably in the range from about 110,000 to about 40,000.
In an alternative embodiment according to the invention, any of said high DE carboxylic acid polysaccharides and said low DE carboxylic acid polysaccharides is an esterified alginic acid.
In a preferred embodiment of the invention, any of said esterified alginic acids is an alginic acid ester of aliphatic, aromatic, araliphatic, alicyclic and heterocyclic alcohols, including esters deriving from substituted alcohols such as esters of bivalent aliphatic alcohols, preferably ethylene glycol or propylene glycol alginate. U.S. Pat. No. 5,416,205 discloses suitable alginic acid derivatives, and the reference is enclosed herewith in its entirety.
In a further embodiment according to the invention, the ester groups of any of said high DE carboxylic acid polysaccharides and said low DE polysaccharides are distributed in a block-wise fashion.
In another embodiment according to the invention, the ester groups of any of said high DE carboxylic acid polysaccharides and said low DE polysaccharides are distributed in a random fashion.
In another embodiment of the invention, a composition comprising at least one carboxylic acid polysaccharide selected from the group comprising pectin esters, alginic acid esters, esterified cellulose ethers, esterified hydroxyethylcellulose, esterified carboxymethyl-cellulose, esterified guar gum, esterified cationic guar gum, esterified hydropropyl guar gum, starch esters, and polymerized sugar esters is used for skin protection and/or alkalinity control.
In a preferred embodiment according to the invention, said carboxylic acid polysaccharide is a pectin ester, preferably a pectin ester of aliphatic, arylaliphatic, cycloaliphatic or heterocyclic alcohols, more preferably an ester of methanol, ethanol, propanol or isopropanol, and most preferably an ester of methanol.
In another embodiment according to the invention, said carboxylic acid polysaccharide is a pectin having a molecular weight in the range from about 5,000 to about 140,000, preferably in the range from about 10,000 to about 125,000, most preferably in the range from about 10,000 to about 40,000.
In another embodiment according to the invention, said carboxylic acid polysaccharide is an esterified alginic acid.
In another embodiment according to the invention, said esterified alginic acid is selected from the group comprising alginic acid esters of aliphatic, aromatic, araliphatic, alicyclic and heterocyclic alcohols, including esters deriving from substituted alcohols such as esters of bivalent aliphatic alcohols, preferably ethylene glycol alginate or propylene glycol alginate.
In another embodiment according to the invention, the ester groups of said polysaccharide are distributed in a block-wise fashion.
In another embodiment according to the invention, the ester groups of said polysaccharide are distributed in a random fashion.
In another embodiment of the use according to the invention, at least one of said carboxylic acid polysaccharide(s) is a high DE carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 70% to about 100%, more preferably from about 80% to about 100%.
In another embodiment of the use according to the invention, at least one of said carboxylic acid polysaccharide(s) is a low DE carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 5 to about 70%, more preferably from about 5% to about 40%, and most preferably from about 10% to about 35%.
In another embodiment according to the invention of the use of a composition, said composition comprises a mixture of at least one of carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 70% to about 100%, more preferably from about 80% to about 100%; and at least one carboxylic acid polysaccharide having a degree of esterification (DE) in the range from about 5 to about 70%, more preferably from about 5% to about 40%, and most preferably from about 10% to about 35%.
The composition according to the invention is suitable for use in personal care products.
In a preferred embodiment, said products are for use on human skin.
In another embodiment, said products are for use on animal skin. In a particular embodiment according to the invention, the skin protecting alkalinity-controlling composition is used in a product selected from the group consisting of skin creams, skin lotions, deodorant products, fragrance products, hair care products, shaving products, soap products, and bath salt products.
In another embodiment according to the invention, the skin protecting alkalinity-controlling composition is used in a product selected from the group consisting of female hygiene products and diapers.
A particular advantage of the present composition is the fact that they are capable of controlling the alkalinity of the surface, to which they are applied, for a prolonged time. As demonstrated in examples 5 and 8, the carboxylic acid polysaccharides are capable of controlling the alkalinity at multiple challenges of alkalinity. This fact can be utilized in e.g. deodorant products, diapers or female hygiene products, which are repeatedly exposed to sweat that is decomposed by micro-organisms to alkaline substances. Thus, a prolonged effective alkalinity control may be obtained by the products according to the present invention.
In another embodiment according to the invention, the skin-protecting alkalinity-controlling composition is used in a product selected from the group consisting of ostomy products and wound care products.
In ostomy products a low solubility polysaccharide, such as a low solubility pectin, should be used, since the ostomy product should remain insoluble for a longer period of time during flushing by body fluids. In this particular case a combination of a low DE and a low pH pectin would provide for a longer durability of the ostomy product during use.
In a particular embodiment such low solubility low DE pectin should be combined with a higher solubility pectin having a higher DE to maintain a skin pH closer to the optimum skin pH of 5.5.
In still another embodiment according to the invention, the skin-protecting alkalinity-controlling composition is used in a product selected from the group consisting of lotionized tissue products, fabric treating products, and laundry rinse products.
Extraction of Pectin
Pectin is extracted using the following steps. The degree of esterification was controlled in the range of about 76% to about 30% through shorter or longer extraction times. The process is as follows:
Preparation of Pectin with Degree of Esterification Below 30%
Preparation of Pectin with Different Molecular Weight
Preparation of Pectin with Degree of Esterification Above 80%
Preparation of Pectin with Different Distribution of Ester Groups
Determination of Molecular Weight (Mw) and Intrinsic Viscosity (IV)
For this, High Performance Size Exclusion Chromatography (HPSEC) with triple detection is used.
Principle: A pectin sample is fractionated according to hydrodynamic volume, using size exclusion chromatography. After separation, the sample is analysed by a triple detector system, consisting of a refractive index (RI) detector, a Right Angle Laser Light Scattering (RALLS) detector and a differential viscometer. Information from these detectors leads to determination of molecular weight (Mw) and intrinsic viscosity (IV). The Mark-Houwink factor is calculated using the molecular weight and intrinsic viscosity as obtained using this method.
Materials:
Method:
Approximately 2 mg of the sample is weighed into a 2000 μl vial. The sample is then dissolved in the auto sampler, by following schedule: 8 μl of ethanol is added, then 1300 μl of acetate buffer (0.3 M, pH 4.8), sample is heated to 75° C. and mixed for 9.9 minutes. 300 μl of the preparation is diluted with 900 μl of acetate buffer, then mixing for 9.9 minutes. Sample is left at ambient temperature for 20 minutes. 100 μl of the sample is injected with a 100 μl full loop and flow rate is 0.8 ml/min. Two detectors are present in line, a right angle laser light Scattering (RALLS) detector (Viscotek) and a dual detector consisting of a refractive index detector and a viscometer (Viscotek).
The specific refractive index increment (dn/dc) value for pectin is set at 0.144. Data from detectors are processed by tri-SEC software (Viscotek).
Determination of Degree of Esterification (DE) and Galacturonic Acid (GA) in Non-Amide Pectin
Principle: This method pertains to the determination of % DE and % GA in pectin, which does not contain amide and acetate ester.
Apparatus:
Chemicals:
Procedure—Determination of % DE and % GA (Acid alcohol: 100 ml 60% IPA+5 ml HCl fuming 37%):
(Chloride test on ash-free and moisture-free basis: Transfer approximately 10 ml filtrate to a test tube, add approximately 3 ml 3 N HNO3, and add a few drops of AgNO3. The filtrate will be chloride-free if the solution is clear, otherwise there will be a precipitation of silver chloride.)
The sample is now ready for titration, either by means of an indicator or by using a pH-meter/autoburette.
Procedure—Determination of % DE only-(Acid alcohol: 100 ml 60% IPA+5 ml HCl fuming 37%):
The sample is now ready for titration, either by means of an indicator or by using a pH-meter/autoburette. Note: It is very important that samples with % DE<10% are titrated very slowly, as the sample will only dissolve slowly during titration.
Titration using indicator:
Blind Test (Double Determination is Carried Out):
1. Add 5 drops phenolphtalein to 100 ml carbon dioxide-free or dionized water (same type as used for the sample), and titrate in a 250 ml glass beaker with 0.1 N NaOH until change of color (1-2 drops).
2. Add 20.00 ml 0.5 N NaOH and let the sample stand untouched for exactly 15 minutes. When standing the sample must be covered with foil.
3. Add 20.00 ml 0.5 N HCl and 3 drops phenolphtalein, and titrate until change of color with 0.1 N NaOH (record it as B1). Maximum amount allowed for titration is 1 ml 0.1 N NaOH. If titrating with more than 1 ml, 0.5 N HCl must be diluted with a small amount of deionized water. If the sample has shown change of color on addition of 0.5 N HCl, 0.5 N NaOH must be diluted with a small amount of carbon dioxide-free water. Maximum allowed dilution with water is such that the solutions are between 0.52 and 0.48 N.
Titration Using pH-Meter/Autoburette:
Using Autoburette type ABU 80 the following settings may be applied:
Blind Test (Double Determination is Carried Out):
1. Titrate 100 ml carbon dioxide-free or deionized (same type as used for the sample) water to pH 8.5 with 0.1 N NaOH (1-2 drops).
2. Add 20.00 ml 0.5 N NaOH while stirring and let the blind test sample stand without stirring for exactly 15 min. When standing the sample must be covered with foil.
3. Add 20.00 ml 0.5 N HCl while stirring, and stir until pH is constant.
4. Titrate to pH 8.5 with 0.1 N NaOH (record it as B1). Maximum amount allowed for titration is 1 ml 0.1 N NaOH. If titrating with more than 1 ml, 0.5 N HCl must be diluted with a small amount of deionized water. If pH does not fall to below 8.5 on addition of 0.5 N HCl, 0.5 N NaOH must be diluted with a small amount of carbon dioxide-free water. Maximum allowed dilution with water is such that the dilutions are between 0.52 and 0.48 N.
Calculation:
V
t
=V
1+(V2−B1)
% DE (Degree of Esterification)={(V2−B1)×100}/Vt
% DFA (Degree of Free Acid)=100−% DE
% GA*(Degree of Galacturonic acid)=(194.1×Vt×N×100)/400
% Pure pectin={(acid washed, dried amount of pectin)×100}/(weighed amount of pectin)
Determination of pH-Drop
Determination of Titration Curves
Propylene glycol alginate—Quantitative determination of the ester groups is carried out by the saponification method described on pages 169-172 of “Quantitative organic analysis via functional groups”, 4th Edition, John Wiley and Sons Publication.
Preparation of Lotion and pH-Drop in Lotion
Lotions were prepared according to the composition:
Since the pH is low, the lotion can be preserved with conventional food-grade preservatives.
Method 1:
Method 2:
The mix was cooled to about 30° C. on cooling bath while stirring and fill into appropriate container.
(Note: This test is indicative, only. It is not possible to read the pH accurately.)
The invention will now be described in more detail with respect to the following, specific, non-limiting examples.
Five samples of different molecular weight, but with similar DE made from dried lemon peel were titrated and the pH drop over time recorded for samples dissolved at 70° C. and 20° C., respectively. The pH drop was measured at 30-32° C. Titration was done using 0.1008 M NaOH. The comment “unstable” refers to the pH-meter, which at high pH values showed an unstable reading.
The data in
Eight samples were prepared with different degree of esterification ranging from about 9 to 93%. The samples were made from dried lemon peel. All were titrated and the pH drop over time recorded for samples dissolved at 70° C. and 20° C., respectively. The pH drop was measured at 30-32° C. Titration was done using 0.1008 M NaOH. The comment “unstable” refers to the pH-meter, which at high pH values showed an unstable reading.
To further elaborate on this point, I define buffer capacity as ml. 0.1 M NaOH required to increase the pH by 1 pH unit, calculated from the part of the titration curve, which is steepest.
Thus, the approximate buffer capacities as calculated from
These results are compiled in
For DE=93.4%, time to reach pH=8 is 2 minutes, for DE=71% it takes 12 minutes, for DE=34.4% the time is 35 minutes and for DE=9.6% it takes 130 minutes. In order to reach pH=7, the difference is even bigger. Pectin with a DE=71 is about 9 times slower than pectin with DE=93.4, and pectin with DE lower than 71% are slower than a factor 10 compared to pectin with DE=93.4.
Thus, if one needs to obtain a rapid pH decrease as a result of alkali generation, pectin with as high a DE as possible is preferred. If, on the other hand, the need calls for slower reduction of pH, then a lower DE would be preferred. Selecting pectin of a specific DE makes it possible to reduce the pH at a specific rate.
Another aspect is to combine pectin preparations of different DE. For example, one might combine a low DE pectin and a high DE pectin to achieve initial alkali consumption or buffer capacity and to provide pH reduction, when the buffer capacity is used.
Two samples were made from dried lemon peel. One was de-esterified with a bacterial pectin esterase, which results in a random distribution of the methyl ester groups. The other was de-esterified with a plant pectin esterase, which results in a block wise distribution of the methyl ester groups. The samples were made to similar DE. Both samples were titrated and the pH drop over time recorded for samples dissolved at 70° C. and 20° C., respectively. The pH drop was measured at 30-32° C. Titration was done using 0.1008 M NaOH. The comment “unstable” refers to the pH-meter, which at high pH values showed an unstable reading.
The pH drop for one sample having DE=71% and made from dried lemon peel was recorded at four different temperatures. The sample was prepared by dissolving the pectin at 70° C. and subsequently cooling the solution to the recording temperature. The temperature was maintained with a thermostatically controlled water bath.
The pH drop for one sample having DE=71% and made from dried lemon peel was recorded at a temperature of 25-27° C. First, the pH was raised to about 10 with 19 ml. 0.1 M NaOH. When the sample had reached a pH of 6-7, the pH was again raised to about 10. This required 1.1 ml. 0.1 M NaOH. When the pH had reached 6-7, the pH was raised a third time to about 10, which required 1.2 ml. 0.1 M NaOH. The sample was prepared by dissolving the pectin at 70° C. and subsequently cooling the solution to the recording temperature. The temperature was maintained with a thermostatically controlled water bath.
Thus, if alkalinity is appears in pulses, for at least three times pectin is able to reduce the alkali. In fact, in one experiment, which went on for seven days, a 200 ml. 1% pectin solution of DE=71% consumed 73 ml. of a 0.1 M NaOH solution. After this period, the DE has decreased to 9.1%.
Thus, 2 g. pectin consumes 7.3 mmol NaOH, which corresponds to about 0.3 g. NaOH. It also means that about 0.23 g. methanol is produced, which in combination with the acid effect of pectin may explain the anti-microbial effect of pectin.
The pH drop for one sample having DE=81.7% and made from dried lemon peel was recorded at a temperature of 30-32° C. The concentration of pectin was 0.05-2%. The sample was prepared by dissolving the pectin at 70° C. and subsequently cooling the solution to the recording temperature. The temperature was maintained with a thermostatically controlled water bath.
Carbon dioxide is soluble in water, and this experiment shows the pH drop of ion-exchanged water over time without the presence of pectin or other additions. The temperature of the water was kept at 25° C. using a thermostatically controlled water bath.
Three samples with degree of esterification ranging from about 55 to about 85% were tested. All were titrated and the pH drop over time recorded for samples dissolved at 70° C. and 20° C., respectively. The pH drop was measured at 30-32° C. Titration was done using 0.1008 M NaOH. The comment “unstable” refers to the pH-meter, which at high pH values showed an unstable reading.
The pH drop for one sample, Manucol Ester ER/K, was recorded at a temperature of 30-32° C. First, the pH was raised to about 10 with 4 ml. 0.1 M NaOH. When the sample had reached a pH of 5-6, the pH was again raised to about 10. This required 2.5 ml. 0.1 M NaOH. When the pH had reached 5-6, the pH was raised a third time to about 10, which required 2.0 ml. 0.1 M NaOH. When the pH had reached about 6, the pH was again increased to about 10, which required 1.5 ml. NaOH. The sample was prepared by dissolving the pectin at 70° C. and subsequently cooling the solution to the recording temperature. The temperature was maintained with a thermostatically controlled water bath.
Buffer Capacities are Calculated to
Thus, PGA provides less buffering effect compared to pectin.
The pH drop for one sample, Manucol Ester ER/K, was recorded at a temperature of 30-32° C. First, the pH was raised to about 10 with 4 ml. 0.1 M NaOH. When the sample had reached a pH of 5-6, the pH was again raised to about 10. This required 2.5 ml. 0.1 M NaOH. When the pH had reached 5-6, the pH was raised a third time to about 10, which required 2.0 ml. 0.1 M NaOH. When the pH had reached about 6, the pH was again increased to about 10, which required 1.5 ml. NaOH. The sample was prepared by dissolving the pectin at 70° C. and subsequently cooling the solution to the recording temperature. The temperature was maintained with a thermostatically controlled water bath.
The pH drop in lotions made according to the two methods described in “Materials and Methods” section 2.1 were measured using pectin of about DE=81.7%.
10 grams lotion was slurried in 50 ml distilled water and pH was adjusted with 0.1 M NaOH to about 10. Pectin concentration in slurry: 0.125%. Temperature: 30° C.
It may seem that when pectin is dissolved in the water phase before mixing with the oil phase provides for a more rapid pH-drop. However, when taking into consideration, that the curve for pectin dissolved in the water phase starts at a slightly lower pH, the two curves are close to identical. Thus, there is nothing to suggest that one of the methods for making the lotion influences the effect of the pectin.
The lotions were tested by 12 persons—6 females and 6 males, with the following remarks from the test persons:
The lotion was also tested on one dog, which had developed a rash on the nose. Treatment of the nose with the lotion twice for one day reduced the rash visibly. To similar treatments over the next two days reduced to rash to an extent, where the rash was difficult to see.
Cloths were prepared according to the method in “Materials and Methods” section above.
FIG. 11.1-11.5 show that irrespective of the concentration of pectin during soaking, and irrespective of the molecular weight of the pectin, the pH-drop is quite similar. However, when the cloth is soaked in a pectin solution, the dried cloth becomes stiffer. Table 11.1 shows this effect:
Table 11.1 shows that as the molecular weight decreases, the cloth can contain more pectin without becoming unacceptably stiff.
A rinse is normally performed using 16 liters of water. Assuming that the rinse dosage is 100 ml, then 0.01% pectin in the rinse corresponds to a pectin solution of 1.57%. 0.05% pectin in the rinse corresponds to a pectin solution of 7.4%. 0.10% pectin in the rinse corresponds to a pectin solution of 13.79%. 0.20% pectin in the rinse corresponds to a pectin solution of 26.47% and 0.05% pectin in the rinse corresponds to a pectin solution of 44.44%.
The effect on Brookfield viscosity of such pectin solutions are shown in table 11.2:
It is clear that as the molecular weights drops, it becomes easier to dissolve the pectin, and in addition the viscosity becomes lower. This enables a rinse to contain more pectin in lower rinse dosage.
For pectin with a molecular weight of 123,000, the maximum concentration of pectin in the rinse is about 2%, for a pectin with a molecular weight of 95,000, the maximum concentration of pectin in the rinse is about 3%, for a pectin with molecular weight of 41,500, the maximum concentration of pectin in the rinse is about 10% and for a pectin with molecular weight of 25,000, the maximum concentration of pectin in the rinse is about 12%.
Pectin products having a DE of 93.4% and 9.6%, respectively were blended 1:1 and 100 g. 1% solution was prepared of the blend through heating to 70° C. The consumption of alkali at 25° C. and the pH-drop over time at 30-32° C. was recorded. Titration was done using 0.1008 M NaOH. The comment “unstable” refers to the pH-meter, which at high pH values showed an unstable reading.
Compared to the individual components, the blend of high DE pectin and low DE pectin provides for an increase in alkali consumption compared to pure high DE pectin and an increase in pH-drop compared to low DE pectin.
A blend of 50% of a pectin having a DE of 93.4% and 50% of a propylene glycol alginate (PGA) having a DE of 55% was dissolved at 70% in a similar manner as in example 12 and compared with the alkali consumption of the individual components.
Compared with the individual components the blend provides an increase in alkali consumption compared to the pectin product alone.
A blend of 50% of a propylene glycol alginate (PGA) having a DE of 85% and 50% of a pectin having a DE of 9.6% was dissolved at 70% in a similar manner as in example 12 and compared with the alkali consumption of the individual components.
Compared to the individual components, the blend provides for an increase in alkali consumption compared to propylene glycol alginate alone, and an increase in pH drop compared to low DE pectin alone.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2004 00649 | Apr 2004 | DK | national |
This application is a Section 371 filing of International Application No. PCT/DK2005/000285, filed 26 Apr. 2004, the disclosure of which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DK05/00285 | 4/26/2005 | WO | 00 | 7/23/2008 |
