The world of gluten free pasta is becoming more and more interesting and newsworthy for the Italian producers. To confirm this trend there are different facts, first of all a waste interest even if not always express, from some of major and historical main industrial brands working in the area towards this type of product; secondary , the implement from some of the most well known producers of their own implants towards this type of product and finally, but not less important, new producers that are welling to get into this market to look out new activities connected to this “new” area of the pasta market.
But what is pushing the world of the Italian pasta producers and not the only one to be more interested in this new type of pasta that with the well known pasta has in common only the shape?
Securely the statistic data that shows how the celiac disease is dramatically increased, how is shown in FIG.1, and it has created a large interest within the Italian producers and not only in them.
The slide shows an exponential increase of this disease that leads to the intolerance to the traditional type of pasta.
The celiac disease is progressively increased: as matter of facts, during the 80s we could observe that 1 person every 3000 (0, 03%) was effected by it; during the 90s, instead, the percentage was 1 person every 1000 (0, 1%); nowadays is 1 person every 100 (1%).
In fact, at the present time the person in Italy with celiac disease are 600.000, but it has been estimated that the one that have a proper diagnosis for it are only 120.000.Every year 10.000 new diagnosis are carried out, with an annual increment of nearly 10% (data from 2010).
Celiac disease in the world
The same trend is been found in the rest of Europe and in the world. The celiac disease vary from a relation of 1:50 in Finland, to 1:232 in Netherlands (Lohiet 2007).
In the United Kingdom, although 125.00 people have been diagnosis with the disease, nearly 500.000, with a percentage equal at 1:1000, are those who are affected, but they haven’t been diagnosed.
In the United States, a recent research showed that one American every 133 (1:133) is affected by the celiac disease (NIH Development Conference on Celiac Disease, 2004).
Even though 97% of the American Celiac do not have a diagnosis, The National Institute of Health Consensus Development Conference on Celiac Disease (2004), rates that 3 millions of Americans, 1% less of the whole population, could be affected by it.
The causes of this exponential increase of this permanent intolerance towards the gluten could be sum up, by using the concept of “environmental pressure” towards the celiac disease, within the following reasons and circumstances of our modern society:
• Increment of gluten consumption in the population: indiscriminate use of gluten in type of food that normally contain it (bread and pasta enriched with it), food that traditionally were gluten free such as (cold cuts, sauces and dressings, stock, soups, sweets, drinks, etc.) food for vegetarian and drugs;
• Cut down on the breastfeeding period, within an early weaning with gluten of the baby: infant feeding needs to be connected with the interaction linked between gluten and genetic predisposition. The breastfeeding period and the age of the introduction to the gluten are fundamental;
• Improvement of diagnosis techniques and far better knowledge of the disease from doctors and paediatricians: in fact, till nearly 10 years ago, only few doctors were able to identify the symptoms of the celiac disease, because it is really insidious and diversified, therefore it was very difficult to carry out the diagnosis.
Pasta and flours
Consequently of what has been said, it is important to understand that it’s very important to produce pasta gluten- free, that can taste as the unique “pasta” of semolina pasta, that the all world envies us for.
Before getting into the ”heart of the matter”, I mean the description and the consecutive analysis of the existing technologies for the production of pasta gluten free, I would like to underline the right denomination for what is called semolina pasta: is the product obtained from the draw, lamination and consequently drying of a mixture exclusively prepared with durum wheat and water (Law n 187/2001).
Therefore, keeping the subject free from any doubt or uncertainty the gluten free pasta, in according to the law, it’s a food preparation done with flours and gluten free ingredients: but for conveniences, in the following article, we will talk only of gluten-free.
Gluten free pasta: targets to reach
The gluten free pasta available on the market today, improved a lot in comparison to the past: in fact, previously it had an unattractive colour; it broke up in the water when it was nearly at the end of the cooking time and emitted an unpleasant smell and finally it had a “funny” taste.
Nowadays, the gluten-free pasta for celiac are far more better, they taste better because, to cut down the cost of the big machineries for the production of this type of pasta it’s necessary to get it desirable also for the non the celiac person , for example member of the family where the person with the disease lives; that’s for few practical reasons: one pan, try to save on gas consumption ( at a the present state of our economy it’s not something not to consider) and more than anything else it’s important that the person with the disease it’s fitting in, without feeling different, especially in his own environment.
In addition it’s important that anybody that shows interest and end are welling to be curious in cooking could approach this type of food. To be able to achieve that it’s important, that not only these person but everybody it’s stimulated in order to push their curiosity to try this type of pasta, so it’s necessary to produce a gluten free pasta that is at the same level of the semolina one, so pleasant to see but that taste good! The looks of it, the colour the shape are of course not the primary issues, but in these areas we have seen big improvements.
Colour and shapes
The colour is far better, definitely the pasta is looking less yellow-orange and it’s been blended with the white colour of the rice, and vice versa the same happened with the rice the yellow-orange colour of the pasta has made the plain white colour of the rice better looking: at the end then, in this way has been made the mixture corn-rice, yellow corn – white corn. Besides, because this product is been thought for more curious people as well, hopefully they will be open to new cooking experiences with this new “type” of taste and colour.
Consequently as well, it’s a pleasure to taste the fragrant and sweet deep black “venere rice”, or the nuance/ tint of the mixture of a variety of cereals and pseudo cereal gluten free, among which the well known corn and rice, it should became the same pleasure to taste other pseudo cereal, but not for any reason less tasteful or good or with less nutritional properties such as quanta, amaranth and buckwheat.
Regarding the gluten free shape, now we can’t pretend very much, expecting to be able to produce the “mezze maniche” or even more the shapes that you find in different areas of Italy such as the “calamarate”, without paying an high price with the end result of a rubbery taste or the unacceptable breaking that occurs during the cooking. Therefore, for the shape type matter, at the moment we need to stick with, the very Italian “spaghetti”, the classical “penne”, the timeless “fusilli” and the strong “sedanini”, all that kind of shapes where it’s easy to reach a reasonable compromise between a non rubbery taste and no breaking throughout the cooking time.
Without any doubts, anyway we don’t have to lose faith , because working hard and seriously we will be able to obtain, in a near future, fantastic gluten-free “mezze maniche” or even an exquisite “calamarata”!
Draw-bronze and slow drying
Some other features that I would like to underline are: the draw-bronze and the slow drying of these sizes. These features are fine for the gluten and the bran, while for the gluten free pasta, the bronze and the slow drying are lethal; it’s already very difficult to hold the starch cession in the water for this type of pasta, so being it gluten-free, the starch is not trapped in the gluten grid, and so increasing the exchange surface (draw-bronze) this lost becomes even easier. The slow drying doesn’t work well with absence of gluten because in this way it doesn’t have to contend the water with the starch, so it doesn’t make sense to carry out a slow drying , because it will only cause longer drying and production time.
Nowadays there is only a famous Italian producer of gluten-free pasta, that overlooking a number of criteria, he is even able to produce gluten-free “tagliatelle a nido”, in addition to all the other shapes that it’s possible to find already on the market.
These should be /are the criteria to follow to reach the same results: the pertinent evaluation of the drying process, the skillful choice of the appropriate drawing machines and inserts (gauging very well thickness, forms and stripes “ad hoc”) very good judgment of the shapes in relation with the pasta thickness and cooking time, the best quality and the right calibration of the gelatinous level of row materials.
One of the most interesting aspect, but at the at the same time one of the most difficult to improve, is the one related to the taste of the product, and regarding this matter, inevitably we need to consider: good results during the cooking time, stickiness, be able to avoid any breaking during the preparation and whistle dressing it and a chewing feeling “al dente” similar to the semolina pasta.
All these features, in the semolina pasta, are related to the quantity and quality of the gluten hold in the durum wheat: in the gluten- free pasta, it’s only possible to “imitate” the quantity and the quality of the starch that there is inside the cereal or pseudo gluten free cereal.
So while in the wheat we need to quantify and qualify the type of gluten, in the cereal and pseudo gluten- free cereal, in the cereals and pseudo gluten-free cereal it’s necessary to quantify and qualify the starch nature.
Gluten and starch chemistry
In relation to what written above, it’s almost impossible not to spend some time writing about the starch chemistry.
Before getting into details, it’s important to talk about the gluten and its extraordinary characteristics as binder and it structuring of the semolina pasta and not only.
The gluten is a protein able to “create” a grid/net : from this grid nature, and so from the gluten in itself, is related the tastiness and the cooking quality of the bran pasta: in fact, the more the gluten grid is well constructed and structured, the most the pasta will keep well during the cooking time and it will be no-sticky when you eat it, that is what every good pasta producer would like to achieve, for his own pasta.
Important to consider is that in this way is possible to obtain a “ clean” cooking water without starch, and that is going to be the evidence that the drying process was done well, because the all starch is been “wisely” trapped into the gluten grid.
Whistle the gluten is a protein the starch is a carbohydrate: on the first one, nearly everything has been written, regarding its technological applications in the semolina pasta productions, on the second the starch, although it’s true that a lot has been written, in relation to its applications in the food industry and other areas, nothing or nearly nothing has been written regarding its appropriate use in the gluten free industry.
Consequently I believe it’s necessary, in this paragraph, to write something more about the starch, in order to understand which one are the main characteristics of this natural polymer that is possible to exploit for a far better use in the gluten free production.
Starch is the energetic “stock” of the plant world. The main starch’s sources are the cereals (wheat, corn, rice) and potatoes. We can find it in the form of granules with a crystalline structure: when we cook the food we modified this structure ( process of gelatinization), so it’s possible to digest the starch.
When the food cool down (retrogradation), it starts few processes of reassociation of the amylase that make the food less digestible.
The characteristics of the starch
The starch is the “back up” carbohydrate of the plants, stored as energy source, synthesize by an enzyme from glucose, in turn produced by photosynthesis:
6 CO2O + 6 H2O + luce → C6H12O6 + 6 O2
The starch composition, that is the union between the amylose and the amylopectin, is catalyzed from an enzyme called starch synthase.
n C6H12O6 + enzima → H-(C6H10O5) n-OH + n-1 H2O
The starch (FIG.2) is a polysaccharide form with 2 polymers : the amylose ( about 20%) (FIG. 3) and the amylopectin (about 80%) (FIG 4), both glucose’s polymers, that are different one from the other for the structure.
Fig.2: Starch at SEM microscope observations (Chemist Institute “G. Ciamician” of Bologna University).
Fig.3: Amylose at SEM microscope observations (Chemist Institute “G. Ciamician” of Bologna University).
Fig.4: Amylopect at SEM microscope observations (Chemist Institute “G. Ciamician” of Bologna University).
The amylose (FIG.5) is a linear polymer in wich the glucose units are linked one with the other with links α(1→4).One amylose molecule can contain till 1000 glucose residue.
Fig.5: Amylose structure.
The amylopectin (FIG.6) is instead a branched polymer very similar to the amylose on witch one unit every 24-30 is insert a ramification through a link α(1→6).
Fig.6: Amylopectin structure.
The starch gelatination (FIG.7) is a process during which we can observe the swelling of the starch granules caused by the water that spread towards the inside and soluble crystalline regions of amylopectin and amylose ; this happens only above the glass transition temperature, Tg, of the amylose granules(50- 70 C, vary from the plant origin or of the ramification degree of the amylopectin), for a period of 10 minutes and if there is an excess of water (at least 70% in weight).
Fig.7: The starch gelatination.
With the scanning calorimetric temperature (DSG) (FIG.8) we can register an endothermic peak partially superimposed to the displacement of the base line ( glass index transition).
Fig.8: Energetic diagram of gelatinization.
Therefore, summing up and summarizing, the starch gelatinazation is a stage from a crystal structure to an amorphous structure (disruption of the crystalline structure of starch) ; whistle the starch retro-gradation ( FIG.9) constitutes the partial restoration of the crystal structure (partial restore of the crystal structures of starch), which takes place following the cooling of the starch.
Fig.9: Energetic diagram of retrogradation.
After these observations it’s necessary to make some qualities considerations regarding the two thermodynamic aspects of the two processes that involve the starch: the GELATINAZATION and the connected retro gradation.
Gelatinization is a thermodynamically not favourite phenomenon (endothermic), therefore does not occur spontaneously but must provide heat from the external environment for a certain period of time to occur.
The retrogradation, on the other hand, as shown in FIG 9, shows an exothermic peak (thermodynamically means that there is transfer of heat towards the external environment), therefore thermodynamically spontaneous.
The thermodynamics of these two processes is also quite intuitive, because you have the breakdown in the gelatinization of a crystal lattice, so you have to break a crystal structure with its links and so you have to provide energy, while the retrograde system tries to return to the initial state , energetically more stable, in which it delivers energy to the external environment.
After this parenthesis we can return to the production of semolina and gluten free pasta.
The superiority of wheat
The “superiority” of wheat comes from a technological nature and is related to the “popularity” of the products that is possible to produce from it.
Only and exclusively the wheat flour dough may produce a cohesive, homogeneous mixture in all their parts, where you can no longer recognize the individual and original flour particles.
The property that distinguishes sharply the wheat mixture from all others is its visco-elasticity, in other words, it can be extended and deformed without breaking; simultaneously, is very elastic and tenacious, capable of maintaining the shape assigned (quality and quantity of gluten).
In the gluten free mixture, the gluten free functions are completed with less prestige, from the starch and from its process of gelatinization that can occurs.
The gluten free paste, compared to the semolina pasta, if they keep all the qualitative characteristics that we mentioned earlier, such as cooking properties, absence of stickiness and little transfer of starch during cooking, they cannot have that characteristic chewiness “al dente “which distinguishes the wheat pasta, but they become “gummy ‘and’ unnatural”.
In conclusion, for the gluten-free pasta, not to break and fall apart during the cooking time, their starch must be completely gelatinized; but, if on one hand, we want to give them a chewiness more natural and closer to that of bran pasta without disruption and breakage of the product during cooking or when touched by a fork, you must find a balance with the process of gelatinization, trying to get to know it to be able to modular :compromise and modulation that can be achieved only through the in-depth knowledge of the nature of the starch and applying the right technological production.
Technological production of gluten free pasta
To be able to approach in the best way this subject, it is good to recall some basic processes of the pasta production, weather it is gluten free or bran; basically for the production of pasta is necessary to follow these phases:
Let us focus on Stages 1-3-4 which are the focal points of both the production of bran pasta, and gluten-free pasta.
During the mixing phase, for the semolina pasta, you must operate in such a way as to form a protein grid, while for the production of pasta gluten free you must try to gelatinize the starch.
These two operations, formation of a gluten grid (creation of a visco-elastic grid) and the gelatinization of the starch (disintegration of a rigid ordered crystalline structure to switch to a rigid amorphous structure), require completely different operating and thermodynamic conditions: we will see this in more detail later.
The drying stage
Let’s now look at the most delicate and important part of the production of semolina pasta: the drying stage.
At this stage, the pasta, when it exit from the shaker (humidity of 25% approximately), must be brought to moisture of 12.5%.
The drying is performed, in modern systems, in large dryers in which the pasta is subjected to continuous tempering and drying.
This succession of operations brings the two fundamental components of the mixture, on one hand the gluten and on the other starch to “fight” for the water . Both are hydrophilic, but the gluten is much more hydrophilic than the starch, therefore during the drying process the gluten, due to its conformation, “locks” the starch in its grid, forming in this way a solid structure and well-crosslinked, so it won’t not allow the starch during cooking, to be transferred.
In fact the less starch there is in the cooking water, the better is the pasta.
As just explained, the drying process of the gluten free pasta is not so critical, as it can be in the semolina pasta, because there is no gluten that has to compete for water with starch.
Additives and ingredients
Before moving on to analyze the various technologies, to understand better the process of production, it is necessary to refer briefly to the additives and / or ingredients that are used for the production of gluten-free pasta. In fact, to give a thicker consistency, many manufacturers make use of starches (maize, rice, potato); protein (eggs, isolated of legumes); hydrocolloid (cmc, xanthan) and emulsifiers (monodiglycerides of fatty acids).
The idrocollodi, such as :xanthan gum, carboxymethyl cellulose, as they mimic the viscoelastic properties of gluten, creating a gel that shows lattice characteristics , but much weaker than the glutinic lattice, improve the gluten-free mixtures.
Emulsifiers, inter lowering in the crystalline structure of starch, create links that allow you to mimic the lattice.
To talk about it is essential to make the readers to understand better the world of gluten free pasta , but to get a good gluten free pasta you cannot use and thus obtain a product with “clean label”, ie by displaying only the names of flour cereals and pseudo cereals and water, just as it happens with semolina pasta, which has a simple label, just as durum and water.
In the Figures 10 and 11 are shown the different structures, obtained by electron microscopy, of semolina pasta and gluten-free pasta.
Fig.10: Comparison between semolina pasta structure and gluten free pasta.
The semolina pasta shows a compact and homogeneous structure, while the gluten free pasta shows a non-compact and homogeneous one.
In conclusion then gluten, poison for the person with celiac disease, but for the food industry very precious ingredient, is a protein appreciated especially for its unique ability to bind water (up to 200% of its weight in comparison to starch that can absorb only 15%) and for its ability to form a reticular structure such as to confer unmatched sensory characteristics.
From my personal and long term experience in all Italian gluten free pasta companies, moving through short but intense periods, even from semolina pasta companies producers, I can boast of having the most comprehensive overview on the production of gluten free pasta: this vision is exhaustive , mainly because it is also supported by a knowledge, surely analysed less in deep, of the process of production of semolina pasta.
After this consideration, I can move now on the description and comparison of different technologies for the production of gluten free pasta.
In the type A technology is used a type of press constructed for the traditional semolina companies , but after it has been seen that it also works very well to produce these new types of pasta suitable for celiacs, where the mixing tank has disappeared, but the entire process occurs continuously and is injected into the press high-pressure steam.
In the type B technology is used a press of the traditional type with no modification.
In the type C is used a press of a traditional type with an upstream cooker, which allows to pregelatinized flours which are then sent to the press.
In the type D technology is used a press of a traditional type, suitably modified.
The great dilemma for producers of gluten free pasta is, in fact, use raw materials pregelatinized (more expensive) or raw materials no pregelatinized (less expensive).
My experience showed as follows:
Technology Type A
Case A: raw materials no gelatinized → final product gelatinized
Case B: raw materials gelatinized → gelatinized final product
Technology type B
Case A: raw materials no gelatinized → final product gelatinized
Case B: raw materials gelatinized → final product gelatinized
Technology Type C
Case A: raw materials gelatinized → final product very gelatinized
Case B: raw materials gelatinized → gelatinized final product
Technology Type D
Case A: raw materials gelatinized → gelatinized final product
Case B: raw materials no gelatinized → final product gelatinized
That explains because gelatinized raw materials that originally were pregelatinized (high temperature)and then retrogradation (cooling and milling); so it is clear that the pushing conditions used in Technology A and Technology D, unlike technology B, restart easily the gelatinization on the retrograde starch, whistle on the starch ,even the most extreme conditions, steam and pressure, are not enough to reactivate the gelatinization (short time and clogging of the press): for these reasons both A and B technology they are not able to obtain a final gelatinized product starting from row materials.
The difference between the A and D Technology, is that with the first, using raw materials with a high degree of gelatinization can avoid to use any additive (mono and diglycerides of fatty acids): result that instead is not achievable with Technology D.
Technology C, having the cooker before the press, sends inside it, it’s gelatinized product, but not retrograded, so you get a finished product gelatinized. However this technology C is not very versatile, because you have to manage another system, the pre-cooking one , with big doubts about the economical results due to the use of row materials, and with important problems of managing.
Beside with this with this system it’s very difficult to modulate the gelatinization of the starch, and so obtain the famous compromise between not too rubbery chewiness typical of gluten free pasta, and the integrity of the products during and after cooking time.
Technology B does not produce a final gelatinized product, even from raw materials gelatinized, because it’s not able to produce during the press conditions those basic conditions that can reactivate the gelatinization on the regressed starch.
In conclusion, the basic concept of the presses for traditional pasta is in sharp contrast with the concept of gluten free pasta presses: the first one we should not have high temperatures to prevent damage and / or degrade the gluten (the proteins are denatured irreversibly with high temperatures), while in the second we must gelatinize the starch, and therefore, it is necessary to raise the temperatures and pressures.
These two types of products, semolina and pasta gluten free pasta, are poles apart, as the first based its full potential on a protein, gluten, and the second of a carbohydrate, starch: Gluten has an elastic grid; the starch has a crystal lattice.
From the analysis made, it is clear then, that those who decide to start this new production of “pasta for gluten intolerant and not” must not be anchored to the concept that much, “it’s still pasta” that’s not true, because semolina pasta is completely different from gluten- free pasta in every aspect, even in the form if we think about it carefully.
So, the invitation that I would like to address to all those who want to pursue this productive activity, and also to all those who are in the field from several years now, is to begin to think seriously about the fact that the gluten- free pasta has its own specific identity, and therefore needs its own unique production technology, consequently you must provide a specific press ,drying diagrams and specific raw materials, “ad hoc” dies and inserts and specific controls, aimed at solving the problems of gluten free pasta.
Surely, my most sincere thanks, is aimed at owners of the company I worked for almost eight years and all those who have always supported and helped me in my work.
A special note of gratitude I have to turn it to Mr. Giacinto Padula and Mr. Ermanno Denti that transmited/passed on me with infinite and real passion all the secrets of semolina pasta and not, and they have introduced me, with great sagacity, in this fantastic world.
• Personal Notes from Patrizia Cristallo
• “Gluten Free Food: science and technology”. Edited by Eimear Gallagher
• “Starch Activities”. Biomineralization and Biocristallography Group. University of Bologna Chemical Institute “G. Ciamician “Prof. G. Falini
• Teaching material – AIC