WO2011096807A1

WO2011096807A1 - Process for the manufacture of an edible dietary fibre composition and a dietary fibre composition

Info

Publication number: WO2011096807A1
Application number: PCT/NL2011/050077
Authority: WO
Inventors: Marinus Jacobus Vervoort
Original assignee: Institute "On My-Way" B.V.
Priority date: 2010-02-05
Filing date: 2011-02-04
Publication date: 2011-08-11
Also published as: NL2004203C2

Abstract

The invention provides a process for the manufacture of an edible dietary fibre composition comprising non-fermentable dietary fibres, comprising the step of: a)treating edible vegetable material with digestive enzymes to remove caloric contributing components such as macronutrients and digestible fibres, to yield an intermediate vegetable material comprising fermentable and non-fermentable dietary fibres; b) treating the intermediate vegetable material with microbes living in the human intestinal tract and/or fermentation enzymes that are present in or originate from these microbes or that are identical thereto, to remove fermentable dietary fibres and c)isolating the composition comprising non-fermentable dietary fibres. The invention further provides a food product comprising a dietary fibre composition obtainable by such process.

Description

Process for the manufacture of an edible dietary fibre composition and a dietary fibre composition

The present invention relates to the manufacture of an edible dietary fibre

composition comprising non-fermentable dietary fibres. The invention further relates to a novel dietary fibre composition which may be obtained by said process.

Dietary fibres are known for their beneficial properties. They can be divided into digestible, fermentable and non-fermentable dietary fibres. Digestible dietary fibres are fibres that can be digested in the human small intestine by enzymatic processes. Digestive dietary fibres typically have a caloric contribution up to about 400 kcal/100 grams of dry matter of fibre. Fermentable and non-fermentable dietary fibres are basically non-digestible for human beings. Fermentable dietary fibres, however, can be consumed by microbes living in the human large intestine. Upon consuming the fermentable dietary fibres, these microbes are themselves consumed in the human digestive system. This process uses energy, meaning that fermentable dietary fibres have a caloric contribution of about 200 kcal/100 grams of fermentable fibre. Non-fermentable dietary fibres are not consumed upon traversing the human intestinal tract. Hence, they do not supply energy to the human metabolism.

For this reason, non-fermentable fibres have a caloric contribution of zero. Dietary fibres, in particular fermentable and non-fermentable dietary fibres, are known for their beneficial health effects. They stimulate the peristaltic activity of the intestines and are believed to reduce the chance of colorectal cancer. They contribute to the capacity of the metabolism to stabilize the glucose level in blood, have a certain capacity to bind harmful or unhealthy substances, have reducing effect on cardiovascular diseases and stimulate defecation in the case of constipation. They also contribute in the prevention of diverticulitis, which is an inflammation of the intestine and supposedly the most abundant complaint of elderly people in the western world.

The three types of dietary fibres have in common that they are considered to be edible. Edible in this context means that a product is consumable for humans or animals with an intestinal tract similar to the human one, e.g. pigs, dogs, cats, rats or apes. Further on, when mentioning the human intestinal tract, or organs or parts contained in said tract, what is actually meant, is the above broad definition.

Edible further means that the composition should traverse the digestive tract, with or without being digested, without any harmful or undesired effect on the health. Both liquid and solid products are considered edible. Wood fibres, are not considered edible and hence are not considered as dietary fibres. Upon consumption, wood fibres may cause discomforts like stomach cramps, or even worse. Wood fibres, or wood-like fibres like e.g. cotton or hemp fibres, are not edible since they contain large amounts of cellulose and lignin. In order to be considered an edible dietary fibre, a fibre should comprise less than 60 wt.-% of cellulose and less than 30 wt.% of lignin, based on total dry matter.

Dietary fibres are typically found in edible material of vegetable origin, also referred to as food raw material. In this context, sources of dietary fibres, in particular non- fermentable dietary fibres, are referred to as edible vegetable material.

Examples of such edible vegetable material are fruit and vegetables, peas, and legumes, but also alleged waste material such as potato peels, fruit peels, citrus pulp and residues of grain. Thus, the range of possible sources for dietary fibres is vast.

The daily consumption of a certain amount of dietary fibres, in particular fermentable and non-fermentable dietary fibres, is believed to contribute to our health. Non-fermentable dietary fibres stimulate inter alia the peristaltic movement of our intestines, supply a negligible amount of calories and bind cholesterol. Unfortunately, western people eat in general too little dietary fibres to take advantage from their contribution to a good health. Indeed, western people consume increasing amounts of energy rich so-called

macronutrients such as carbohydrates, proteins and fats. The western taste has evolved into a refined food products taste, meaning that the macronutrients contained in food products are more pure, easy to digest and energy-rich. Examples of such refined food products are white bread, granulated sugar, chips, pale lager beer and so on. A drawback of the increasing purity of macronutrients is that the amount of micronutrients in food products gradually decreases. Micronutrients are nutrients present in trace amounts in food products, whereas macronutrients are the main components of food products. Said micronutrients have a specific nutritional value, typically fulfilling an essential task, e.g. neutralizing free radicals in the body. Examples of micronutrients are vitamins, minerals and bioactive substances. Bioactive in this context means positive interaction with or effect on any cell tissue in the human body. Shortage of micronutrients causes all kinds of disorders and illnesses. In the western world, an increase of micronutrient deprivation related illnesses is observed.

Another drawback of the increasingly refined food products is that components which are in general considered less tasteful, like e.g. hulls, husks, bran, small kernels and germs are reduced or even excluded from said food products. This is an unfavourable

development, since these components contain the largest amounts of (non-fermentable) dietary fibres and are rich of micronutrients.

To increase the consumption of dietary fibres, food product manufacturers develop food products which contain larger amounts of dietary fibres. A product containing dietary fibres is known for instance from EP-A1 -0166824. It describes a composition having an increased ratio of dietary fibre to digestible material (macronutrients) to allow for consumption of high percentages of so-called insoluble dietary fibre (herein referred to as non-fermentable fibres), without the disadvantage of high caloric intake. The starting material for the composition is cereal bran which is enzymatically and chemically purified and then isolated. The insoluble dietary fibre is then coated with a soluble dietary fibre. Although this dietary fibre composition has the above benefits to some degree, it has the disadvantage of containing both fermentable (soluble) and non- fermentable (insoluble) dietary fibres, meaning the composition is a relatively rich source of energy. Besides, due to the manufacture process, the composition hardly contains micronutrients.

Recently, a product for treating overweight has entered the market which consists wholly of non-fermentable fibres. This product is manufactured from wood fibres and is chemical treated as a starting material. The product has no caloric contribution and provides some of the above advantages of dietary fibres, i.e. giving a satisfied feeling, stimulating peristaltic activity and binding cholesterol. However, this is not an appropriate food product. Wood fibres are generally not suited to be digested or fermented in the human digestive system. They need special treatment in order to be consumable and to be useful as product for treating over weight. According to the present invention, and from a human perspective, the wood fibres are no dietary fibres. Moreover, the product does not contain micronutrients. This means that this food supplement cannot be used as e.g. meal replacement. Besides, food products should meet a vast number of FDA regulations across the world. It will be very hard for a product consisting mainly of wood fibres which are not digestible for humans to be acknowledged as a food product. A more acceptable product would therefore be quite attractive.

People who want to loose weight may benefit from a meal replacement which helps to loose weight and preferably contains essential micronutrients as well.

It is therefore an object of the present invention to provide an edible dietary fibre composition which has a negligible, zero or even negative caloric contribution, which exhibits all the advantages associated with the consumption of dietary fibres and which comprises valuable micronutrients.

It is another object of this invention to provide a dietary fibre product which can be added to, processed in or processed as a food product.

This object is achieved by a process for the manufacture of an edible dietary fibre composition comprising non-fermentable dietary fibres, comprising the step of: a) treating edible vegetable material with digestive enzymes to remove caloric contributing components such as macronutrients and digestible fibres, to yield an

intermediate vegetable material comprising fermentable and non-fermentable dietary fibres; b) treating the intermediate vegetable material with microbes living in the human intestinal tract and/or fermentation enzymes that are present in or originate from these microbes or that are identical thereto, to remove fermentable dietary fibres and

c) isolating the composition comprising non-fermentable dietary fibres.

The invention is based on the inventor's insight that microbes living in the human intestinal tract can be used to manufacture a dietary fibre composition that does not supply energy to the human metabolism upon digestion and that is rich in non-fermentable dietary fibres and comprises micronutrients. Thereto a dietary fibre is first subjected to an enzymatic treatment to remove digestible fibres. The non-digestible residue, i.e., the "intermediate vegetable material", is then treated with microbes or enzymes associated with such microbes to remove fermentable fibres. Whereas one would expect to throw away the resulting product comprising non-fermentable fibres, the present inventor has found that such product, comprising non-fermentable fibres and micronutrients provides an excellent dietary fibre composition. Said composition might be manufactured from all kinds of vegetable material. This means that not only the product comprises micronutrients, but also that the spectrum of micronutrients can be tuned as desired by selecting the proper type or a combination of types of vegetable material. Such a dietary fibre composition can be used in a food product as an aid in loosing weight, as a slimming snack or even as replacement for a meal. It can also be adapted for consumption for people with diabetes or osteoporosis.

The invention is hereafter discussed in greater detail.

According to the invention an edible composition is manufactured. The composition is edible as such, but probably the composition as such is hygroscopic and not so tasty. This means that preferably the composition is further processed to manufacture food products with an at least acceptable taste. Further processed means that the composition may be added to food products, that the composition may be converted into a food product which comprises also small amounts of other substances to improve edibility or that the

composition may be processed essentially pure for the manufacture of e.g. slimming pills or capsules.

The composition is manufactured from edible vegetable material, comprising both fermentable and non-fermentable dietary fibres. As said above, wood fibres are not considered dietary fibres since they contain high levels of cellulose and lignin. Preferably, dietary fibres according to the invention comprise less than 60, more preferably less than 50, most preferably less than 40 wt-% of cellulose and/or preferably less than 30, more preferably 25, most preferably 20 wt-% of lignin, all percentages based on the dry matter content.

According to the invention, the intermediate vegetable material is subjected to a fermentation process using microbes, which includes mixtures of microbes. Alternatively, the intermediate vegetable material may be treated with enzymes that are present in, or originate from such microbes, or are identical to such enzymes. Since the isolation of enzymes from microbes living in the human intestinal tract tends to be difficult, it is preferred to teat the intermediate vegetable material with microbes living in the human intestinal tract. The microbes used have preferably been isolated from human faeces. Such a treatment is known from published studies, such as, W.V. Titgemeyer et al., Am. J. Clinical. Nutr., 1991 , 53: 1418-1424, and M.I. McBurney et al., J. Food Sci., 54: 1989, 347-350. However, in these studies the composition with non-fermentable fibres was not isolated nor used for the manufacture of a dietary product.

In the present process, fermentable dietary fibres are fermented by enzymes, i.e. fermentation enzymes, present in the microbes. The microbes preferably used are microbes which live in the human large intestine. Advantageously, the selected cultures containing the microbes, can show little toxic or harmful activity or small side effects and have negligible pathogenic effects. Preferably, during the fermentation process, the toxic and pathogenic effects are low. The fermentation process is not the result of the activity of one particular microbe species, but the result of a complex symbiotic relationship between at least several microbe cultures. Above-mentioned microbes may be isolated from their natural habitat and subsequently cultivated. Actually, the fermentation enzymes present inside the microbes are fermenting the fermentable dietary fibres. According to one embodiment of the invention, these fermentation enzymes may be isolated from the microbes, thereby killing the microbes and thereby keeping the essential enzymes intact. Subsequently, these isolated

fermentation enzymes may be used to ferment the fermentable dietary fibres. In doing so, any pathogenic or toxic risks are further reduced.

Fermentation enzymes, corresponding to those isolated according to the

embodiment described above, and commercially available and/or of synthetic origin, may also be used in step b). As explained above, the isolation of enzymes from microbes may be cumbersome.

As stated hereinbefore, the intermediate vegetable material is treated with microbes to remove fermentable dietary fibres in step b). In order to enable the microbes to perform the above task, the edible vegetable material has been pre-treated. This pre-treatment for instance may comprise cleaning, mixing, homogenizing and/or pasteurizing the edible vegetable material. Optionally, the pre-treatment step is followed by a dissolution step in order to retrieve the nutrients present in the vegetable material. To perform this dissolution step, the vegetable material may be treated with an acidic or basic solution, if necessary carried out under pressure and/or elevated temperature. It is understood that the above pre- treatment and dissolution step are common practise for the skilled person who also knows which specific pre-treatment and/or dissolution step could suitably be carried out for a specific type of vegetable material. This skilled person also knows that it might be necessary to remove off-flavour substances upon pre-treating the vegetable material. Off-flavour substances are substances with an unpleasant or undesired flavour or smell. Said off- flavour substances may be formed as side or rest products when pre-treating the vegetable material. Off-flavour substances can also be present due to natural occurring decay processes in the vegetable material. The skilled person further knows that removing off- flavour substances or applying certain chemical, mechanical or thermal treatment steps might be necessary during the whole manufacturing process.

According to the invention, the dietary fibre composition is manufactured from edible vegetable material comprising non-fermentable dietary fibres. In addition to these non- fermentable dietary fibres the edible vegetable material may also comprise digestible and/or fermentable dietary fibres and/or caloric contributing components like e.g. macronutrients such as carbohydrates, fats and proteins. Typically, the vegetable material has a certain caloric value, meaning that upon consuming this vegetable material, energy is supplied to the metabolism.

Preferably, the vegetable material comprises less than 400, preferably less than 300 and most preferably less than 200 kilocalories per 100 grams of dry matter of said vegetable material. This caloric value may be an intrinsic property of a particular vegetable material, but the vegetable material having the above caloric value may also be prepared by removing calorie rich components from an original source of edible vegetable material with more than 400, preferably more than 300 and most preferably more than 200 kilocalories per 100 grams of dry matter. Besides using microbes, or the enzymes present in the microbes, also other means may be used to render the caloric contributing nutrients inaccessible. Examples of such other means are the Maillard and related reactions, according to which digestible nutrients such as sugars are rendered inaccessible by heating the nutrient containing food product, thereby inducing a reaction between certain chemical compounds present in the food product, e.g. a sugar and an amino acid in the case of the Maillard reaction.

Microbes digesting macronutrients and dietary fibres need energy to carry out their task. This energy is inter alia obtained by consuming micronutrients present in the vegetable material. This means that the content of micronutrients in the composition is suboptimal, since parts of these micronutrients are consumed by the microbes.

In order to increase the amount of micronutrients in the dietary fibre composition, prior to step b), the edible vegetable material is treated with digestive enzymes to remove caloric contributing components such as macronutrients and digestible dietary fibres in step a). Without such macronutrients and digestible dietary fibres to live on, the microbes used in the process of the invention will consume the fermentable dietary fibres, leaving the non- fermentable fibres and most of the micronutrients, intact.

Enzymes are normally highly specific towards one specific type of reaction. To remove a certain type of fatty acid, a different enzyme should be used than to remove a certain type of carbohydrate. Therefore, in order to remove the macronutrients and digestible dietary fibres, preferably a mixture of digestive enzymes is used. The enzymatic treatment may be carried out in one step, i.e. contacting the vegetable material with an enzyme solution comprising all required enzymes. However, the enzymatic treatment may also be carried out in various sub steps.

The enzymes used to remove the macronutrients are so-called digestive enzymes, meaning they leave the fermentable dietary fibres in tact. Digestive enzymes are inter alia found in the digestive tract of animals (including humans) where they aid in the digestion of food. Preferably, the enzymes are selected from proteases and peptidases which split proteins into amino acids, lipases which split fat into three fatty acids and glycerol and carbohydrases which split carbohydrates such as starch into sugars. Also esterases may be used, separately or in combination with one or more of the digestive enzymes mentioned hereinbefore. More preferably, commercial available digestive enzymes like e.g. Econase, i.e., non-starch polysaccharides enzymes, such as xylanase, available from ABVista, and Alcalase, i.e., a protease commercialised by Novozymes, are used to remove the macronutrients and digestible dietary fibres.

After the enzymatic treatment the reaction products will be separated. Extracted substances which represent a nutritious and/or commercial value can be reused and for that purpose will successively be separated, isolated and purified. Examples of said substances are glucose, peptides, fatty acids, etc..

As said before, the dietary fibre composition is manufactured from edible vegetable material.

According to a preferred embodiment, the vegetable material comprises vegetable material which is derived from the processing of agricultural or horticultural crops.

Preferably, the vegetable material contains large amounts of non-fermentable dietary fibres. This way, less macronutrients and degraded digestible and fermentable dietary fibres need to be separated from the non-fermentable dietary fibres, leading to a lower energy consumption.

More preferably, the vegetable material is selected from the group comprising sugar beet pulp, potato peelings and residues of potato processing, residues of fruit and vegetable processing like e.g. skins of tomatoes, residues of grain, seeds and legume processing like e.g. hulls, husks, bran, brewer's spent grain, residues of the wine industry like kernels and skins of grapes, grasses, herbs, straw and chaff that are typically considered waste, or combinations thereof.

Most preferably, the organic waste material is selected from the group comprising of spent grain, beet pulp, citrus pulp, grass meal, oat or wheat waste meal, lupines, rice waste, rice feed meal, flour, potato peel, flaxseed hulls and husks, sesame seed hulls and husks, grape seed junk and grape pulp. Most preferably, the edible vegetable material is selected from selected from the group consisting of seeds and skins of grapes, of tomatoes, of passion fruit, cotton seed and mixtures thereof.

Upon selecting the edible vegetable material, the amount of non-fermentable dietary fibres and micronutrients present in the vegetable material plays a role, defining the quality of a particular vegetable material. Also economic parameters such as the price of a particular vegetable material and the costs of processing said vegetable material may play a role. Preferably, the vegetable material is selected which has the most favourable price/quality ratio.

In another preferred embodiment of the invention, the dietary fibre composition comprises also micronutrients, as opposed to macronutrients.

In step c) the composition comprising non-fermentable dietary fibres is isolated from the microbes and/or fermentation enzymes. The skilled person will realise how the isolation can effectively be achieved. Such isolation may involve filtration, washing, drying and/or sterilisation.

Another aspect of the invention relates to a dietary fibre composition and a food product comprising said composition. Such a composition is suitably obtainable or obtained from the process described above.

In particular the invention is related to an edible dietary fibre composition having less than 60, preferably less than 40, more preferably less than 20 kilocalories per 100 grams of dry matter, comprising non-fermentable dietary fibres and micronutrients, wherein the combined amount of macronutrients, digestible and fermentable dietary fibres is less than 15, preferably less than 10, more preferably less than 5 wt-%, based on dry matter.

The passage of non-fermentable dietary fibres through the intestinal tract requires energy. The current inventor realized that such non-fermentable dietary fibres combine the supply of essentially zero, or less than, metabolic energy with the beneficial effects attributed to dietary fibres and micronutrients, thus providing a nutritious and high-quality dietary fibre composition.

In a preferred embodiment, food additives with a beneficial effect are added to the dietary fibre composition. Preferably, these additives have a stimulating effect on the metabolism, i.e. their consumption accelerates the metabolic rate or increases body temperature. More preferably, these additives are selected from the group consisting of capsiate, epigallocatechin gallate (EGCG), caffeine, L-tyrosine and iodide.

According to the invention, the dietary fibre composition can be used in a food product. Preferably, the composition is first conditioned. The process of conditioning may comprise chemical, mechanical and/or thermal treatment steps; the addition of specific substances which have a positive influence on the final food product, or the removal of off- flavour components. The particular conditioning process is determined by the requirements of the final food product. As an example, the dietary fibre composition may be gelatinized in order to manufacture a food product with a certain bite. For that purpose, a certain amount of a weak organic acid may be added to the dietary fibre composition in order to

manufacture an airy and crispy food product.

According to the invention, the dietary fibre composition can be used in a food product. For different types of food products, different requirements exists. Slimming products, for instance, preferably supply as few calories as possible. As another example, people suffering from diabetes benefit from food products which comprise different kinds of carbohydrates, i.e. carbohydrates having a different glycemic index. As a further example, food products for people suffering from osteoporosis are considered. These food products preferably comprise micronutrients such as vitamin D and calcium bearing minerals which have a beneficial effect on bone strength and stability.

According to a preferred embodiment of the invention, the dietary fibre composition can be added to food products like e.g. bread products, pastry, cereals, snacks, pasta and drinks. Preferably, the dietary fibre composition is added in an amount of at least 10 wt-%, more preferably in an amount of from 10 to 40 wt-%. A food product manufactured this way contains less energy and is more healthy, while retaining its original taste or acquiring a more favourable and special taste.

According to another preferred embodiment of the invention, the dietary fibre composition itself can be a starting material for a food product. The resulting food product may comprise about 70 wt-% or higher of the dietary fibre composition. Said food product is prepared by chemically, mechanically and/or thermally converting the dietary fibre composition into said food product. Advantageously, such a food product may be a special purpose food product as defined above, i.e. a slimming product, a diabetes product or an osteoporosis product. Preferably the food product is in the form of a bar, a cookie or biscuit. Advantageously, the effect can be reinforced by adding additives to the food product. For example, it may be beneficial to add calcium to an osteoporosis bar.

In a preferred embodiment, specific macronutrients are added to diabetes products.

More preferably, these macronutrients are carbohydrates with various glycemic indices. According to still another preferred embodiment of the invention, the dietary fibre composition is used to manufacture a dietary supplement. Such a dietary supplement is prepared by chemically, mechanically and/or thermally converting the dietary fibre composition into the dietary supplement. Preferably, the dietary supplement is in the form of a pill, a capsule. Advantageously, the effect can be reinforced by adding additives that enhance the metabolism.

At the end of the process, the product may be sterilized, for instance by heating. Traces of macronutrients and/or fermentable dietary fibres, if any, may be converted into indigestible matter by a controlled Maillard reaction.

Claims

1 . A process for the manufacture of an edible dietary fibre composition comprising non- fermentable dietary fibres, comprising the step of:

a) treating edible vegetable material with digestive enzymes to remove caloric contributing components such as macronutrients and digestible fibres, to yield an

c) isolating the composition comprising non-fermentable dietary fibres.

2. The process according to claim 1 , wherein the edible vegetable material comprises less than 400 kilocalories per 100 grams of dry matter of vegetable material and wherein the non-fermentable dietary fibres consist of less than 60 wt-% of cellulose and less than 30wt-% of lignin, based on dry matter.

3. The process according to claim 2, wherein the intermediate vegetable material comprises at least 90 wt% of fermentable and non-fermentable dietary fibres, wherein the non-fermentable dietary fibres consist of less than 60 wt-% of cellulose and less than 30wt- % of lignin, based on dry matter.

4. The process of any one of the preceding claims, wherein the digestive enzymes are selected from proteases, peptidases, lipases, esterases, carbohydrases and mixtures thereof.

5. The process according to one of the preceding claims, wherein the edible vegetable material is derived from agricultural or horticultural crops.

6. The process according to claim 5, wherein the edible vegetable material is selected from the group comprising sugar beet pulp, potato peelings and residues of potato processing, residues of fruit and vegetable processing, residues of grain, seeds and legume processing, brewer's spent grain, residues of the wine industry, grasses, herbs, straw and chaff, or combinations thereof.

7. The process according to claim 5, wherein the edible vegetable material is selected from the group consisting of seeds and skins of grapes, of tomatoes, of passion fruit, cotton seed and mixtures thereof.

8. The process according to one of the preceding claims, wherein the

intermediate vegetable material is treated with microbes living in the human intestinal tract.

9. The process according to claim 8, wherein the microbes have been isolated from human faeces.

10. Process according to any one of the preceding claims, wherein the isolation of the dietary fibre composition involves filtration, washing, drying and/or sterilisation.

1 1 . Dietary fibre composition comprising non-fermentable dietary fibres obtainable by a process according to any one of claims 1 to 10.

12. A dietary fibre composition according to claim 1 1 , comprising non-fermentable dietary fibres in an amount of at least 85 wt%, based on dry matter.

13. The dietary fiber composition according to claim 1 1 or 12, wherein the composition comprises additives selected from the group consisting of capsiate,

epigallocatechin gallate (EGCG), caffeine, L-tyrosine and iodine.

14. The use of the dietary fibre composition of any of claims 1 1 to 13 in a food product.

15. A food product comprising the dietary fibre composition of any of claims 1 1 to

13