One of the charms of wheat tortillas is their convenience. Wrapped around a filling, they quickly transform into a tasty meal to be eaten at leisure or on the go. Or that’s the theory. For many busy consumers and caterers, the charm can quickly fade when tortillas stick together in the packaging, only to tear when pulled apart.

Although tortilla adhesiveness is a recognized problem, only a few scientific studies have been made on the subject. These attribute responsibility to a complex combination of technical aspects, among them water activity, polar surface energy and starch crystallinity.

Our own experience at DuPont is that various ingredients have the ability to reduce the issue. But they do not work alone. Storage conditions also play a role, particularly temperature, both immediately prior to packing and during storage, and the degree of pressure placed on tortillas when stacked in warehouses.

We decided to test our hypothesis that storage factors actually have greater influence on the adhesiveness of tortillas than the ingredients in the recipe.

Using our test recipes, we tested a series of parameters over a 30-day storage period, taking measurements on days 7 and 30. This is what we looked at:

• The degree of adhesiveness when using alternative types of oil and shortening in the test recipes, each recipe containing 8% fat based on the flour
  • The change in adhesiveness observed when taking out emulsifier from the recipe
  • The level of adhesiveness in tortillas stored at 20°C, 40°C, or at 20°C while subject to 6kg of pressure

Some of our key findings are illustrated in the two graphs below. These clearly show that storage factors have a much greater impact on tortilla adhesiveness than functional ingredients. While the use of an ingredient blend does reduce the issue to some extent, stickiness will inevitably increase when tortillas are stored at high temperature or under high pressure.

Combine an optimised ingredient blend with an appropriate storage strategy, and your tortillas are more likely to meet expectations for convenience.

We used POWERFlex® 2201 for our trial.

Fat reduction is an excellent place to start whether you are looking to raise the nutritional profile or cut the cost of your tortilla formulation. Just as with any other food product, that means compromises, both functional and sensory. But, with a little help, it is possible to make up the shortfall.

With the fat content of a typical wrap at 5-10%, fat reduction by 50% or more will bring considerable savings. The question is: how do you compensate for the loss of dough elasticity and eating quality?

Restoring elasticity

At DuPont Nutrition & Health, we have investigated ways to restore elasticity in order to maintain the desired tortilla diameter. One obvious method is to subject the dough to more pressure during pressing. The drawback of this approach, however, is that it will often result in a tortilla with an irregular shape.

Alternatively, we have found that the use of enzymes can clip the structural proteins and fibres in flour. In this way, the processing aids relax the dough, giving it the elasticity required to press it out to the standard diameter.

Keeping the softness

Eating quality is also critical, as the fat provides the soft, moist feel that turns such flatbreads into a pleasant, sensory experience. This is where emulsifiers make a difference by forming a complex with amylose, one of the two starch fractions. The emulsifier, which is widely used in bread, has a crumb softening effect that consumers perceive as fresh and moist.

The emulsifier and enzymes we have tested are part of a customised blend specifically developed for fat-reduced tortillas. For best results, the blend should be used in addition to an ingredient solution for optimising tortilla softness and flexibility and extending shelf life.

Check out your flour

Before adding any emulsifier-enzyme system to your formulation, you need to test the quality of your flour. Selecting the right dose depends on gluten content and strength and the amount of non-starch polysaccharides in the flour – not to mention the total fat content of the tortilla recipe.

Once you get it right, it should be plain sailing. Even with just 2% fat based on the flour, few consumers will notice the difference.

We used POWERFlex® 401 from the DuPont™ Danisco® range for our trials.

Variety is the spice of life in the bakery sector where ethnic breads are capturing an increasing amount of consumer attention. According to Mintel, the European market for flatbreads is on the verge of booming, driven by a widespread desire for alternatives to traditional bread products.

Mintel has gathered statistics from the UK, where ethnic flatbreads are already widely enjoyed for their taste, texture and versatility. These show continuous growth in value sales of the traditional Indian naan and chapatti since 2008.

An estimate from 2012 gives naan a 17% share of the UK speciality bread market, second only to wraps at 24%. The figures reflect retail value sales from 2010-2011, when speciality bread achieved the highest growth of all bread segments.

In the wake of the popular Mexican tortilla, consumer interest for other ethnic breads is expected to spread throughout Europe. And not all of them come from far afield. For example, Italian piadina, an unleavened flatbread from the Emilia-Romagna region, is among the bread specialities now on sale in a number of UK supermarkets.

From artisanal to industrial

Common to all such ethnic breads is their artisanal roots as staple food items made for day-to-day consumption. This is where manufacturers face their major obstacle when preparing an authentic handmade product for industrial production – the extension of shelf life from one day to several weeks or more.

To someone buying naan bread at the supermarket, it is often apparent that this issue has yet to be solved. Products quickly tend towards dryness and cracking, defects that the recommended sprinkling of water and spell in the oven fail to remedy.  

Solutions do exist, however.

Hanging on to freshness

One possibility is to use an ingredient system that draws on the functionality of hydrocolloids, emulsifiers and enzymes. While the strong water-binding ability of the hydrocolloids maintains bread moistness, enzymes and emulsifiers contribute to longer lasting softness of the crumb.

Over the years, we have worked with a number of possibilities for maintaining moistness and softness for up to 30 days. An important parameter in respect of naan bread is that it keeps a softer structure for good tearability during consumption. In our experience, fresh-keeping quality can be significantly improved with a limited impact on overall costs.

Regardless of which ingredient system you choose, modified atmosphere packaging technology is a must if the goal is a 30-day shelf life. Given the right conditions, ethnic flatbreads can boom into Europe with their softness and flexibility intact.

The ingredient system mentioned in this article is part of the DuPont™ Danisco® POWERFlex® range.

Hordes of private label and brand products are squeezing profits on the growing tortilla market. In some areas, retail prices are, today, so low that flatbreads are fast becoming a commodity product.

To add more value to your wraps, you need to differentiate. Targeting new eating occasions could be the way.

Challenging the general perception of the wheat tortilla as a savoury product, our application specialists have focused on developing an inspirational sweet tortilla concept that also makes a convenient on-the-go snack.

Exotic tropical wrap

What they have come up with is a sweet coconut tortilla that is soft and enjoyable straight from the freezer. Rolled inside it is a refreshing coconut-flavoured ice cream and tangy pineapple ripple.

One of our emulsifier-enzyme systems secures the necessary dough-handling properties and tortilla shelf life. Despite the content of dessicated coconut, our trials have shown that efficient processing can still be achieved.

Consumers can enjoy our exotic tortilla concept at their leisure. During consumption, the tortilla is better able to contain the melting ice cream than a standard ice cream cone. The tortilla works equally well with other sweet fillings, such as fruit or chocolate spread, making it an ideal snack alternative to cakes and muesli bars.

Health and texture

Other opportunities exist to give the concept a healthy twist by using a wholemeal or rye tortilla.

In most cases, this will require the addition of extra gluten to the recipe and a higher emulsifier-enzyme dose to make up the gluten shortfall when wheat flour is either reduced or taken out. Even in recipes based on 100% rye flour, it is possible to overcome the tendency towards dryness to secure long-lasting softness and a consumer-friendly taste.

The original Mexican tortilla has attained international popularity. Extending the traditional eating occasions is the next step along the path of continuing success.

We have used POWERFlex® 2201  for the coconut tortilla and POWERFlex® 2208 for the whole grain and rye concepts.

Get into the car and drive to the local service station, and you’ll probably find a good selection of fast, convenient snacks. What is equally probably is that very few of them will offer much in the way of nutrition.

With healthy snacking one of the top ten trends listed by New Nutrition Business in its 2013 Food Nutrition & Health report, that points to a market opportunity just waiting to be tapped.

In our application labs here at DuPont, we decided to investigate possibilities for filled tortilla wraps to bring some healthy options to the on-the-go segment.

Overcoming the water hurdle

One limitation is immediately obvious: water content. To stop the filling leeching out into the wrap and making a soggy mess, both the filling and tortilla must have the same water activity. In other words, the filling must contain very little water. Most industrial bakery fillings overcome this by having a high sugar content – not exactly compatible with good nutrition!

For this reason, we turned our attention to developing a filled tortilla concept either for a very short shelf life – maximum two days – in the refrigerator or for storage in the freezer.

One of your five a day

Having eliminated the water issue, we put together a savoury filling based on a medley of vegetables – a single portion providing one of the five or six daily servings of fruit and vegetables that many health authorities recommend.

Prebiotic polydextrose was added to enable an on-pack high-fibre claim. An ‘invisible’ fibre, polydextrose has no impact on taste or texture.

Hot and stable

That achieved our nutritional goals. But, to make a truly delicious snack, we knew our filled wrap needed to be enjoyed hot. This called for a way to keep the filling in place during heating and maintain a pleasant, non-sticky mouthfeel.

Through our work with stabilisers, we have gained a broad overview of how they interact in combination, contributing stability and texture. Using this knowledge, we were able to draw on an existing stabiliser system in our portfolio to give the vegetable filling the right functionality for on-the-go snacking.

The system secures the necessary heat stability to ensure the filling does not ‘cook’ in the microwave and provides limited viscosity so the filling is easy to pump and apply to the wrap on processing lines. Just as important, there is no messy leakage during consumption.

Our inspirational concept is designed to take a place alongside the other bake-off products stocked by service stations, kiosks and other fast-food outlets. A convenient, tasty flatbread that helps fill the healthy snack gap

The concept makes use of Litesse® Two polydextrose and GRINDSTED® FB 840 Stabiliser System.

Keeping tortillas soft, moist and mould-free has been a top-of-mind issue since the first day they went into factory production. While the traditional, handmade wrap is made for day-to-day consumption, shelf-life expectations for its industrial counterpart stretch from one or two months all the way up to nine.

To fulfil these expectations, two key functionalities must be integrated in tortilla formulations: the ability to resist the onset of mould, and a fresh-keeping property that maintains flexibility and an appealing texture and mouthfeel.

In flatbreads stored at room temperature, a pH level around 7 and high water activity create the ideal conditions for mould. Measures for controlling water activity include partial replacement with glycerol and the use of modified atmosphere packaging. But, when it comes to mould inhibition through a lower pH, the task is a little trickier.

The pH challenge

At DuPont, we have run many trials to determine the best methods for reducing tortilla pH. Only when pH is low are preservatives able to exert a mould inhibiting effect. Challenges arise, however, when pH reduction of the dough has negative consequences for processing and the quality of the final baked tortilla.

Acids are an obvious choice for achieving a lower pH – our preference is to use the organic acids, citric and malic acid. But problems arise when they are released too quickly in the dough and react prematurely with the sodium bicarbonate. CO₂ is then produced too early in the process, causing unappealing translucent patches and excessive puffing in the final baked tortilla. At the same time, the dough becomes stiff, inelastic and hard to press out to the desired diameter.

Delayed release

To overcome such issues, we work with encapsulation technology. The acid is then locked inside a fat-based coating to delay its release. This ensures the optimum conditions for dough processing and development before the acid acts upon pH, reducing it to around 5.2 for effective mould inhibition.

At the moment, our bakery specialists are looking at new opportunities for optimising mould inhibition. These include acid coating materials based on certified sustainable mass balance palm oil and a palm-free emulsifier based on rapeseed oil.

Inhibiting staling

Preserving the fresh-keeping quality of tortillas requires another approach. Here, we have been able to draw on the know-how obtained from our work with fresh-keeping in bread. This has contributed to a series of optimised solutions that combine hydrocolloids, emulsifiers, enzymes and encapsulated acids. One of the primary functionalities is the ability to delay the retrogradation of wheat starch, which is a major contributory factor in staling.

The result is tortillas with a stay-fresh feel, lasting flexibility and no dry edges – ready to be wrapped around a filling without cracking even after nine months on the shelf.

Send us a message via this page if you have questions about fine-tuning your tortilla formulation to meet the shelf-life expectations of your market.

For our tests, we used POWERFlex® 3201 from the DuPont™ Danisco® range.

A week, a month, two months – expectations for the fresh-keeping shelf life of cakes continue to push the limits. Whether they have just left the production line or reached their last sell-by date, cakes have to deliver maximum indulgent quality. Anything less, and they are destined to disappoint.

One means of maintaining freshness over an extended shelf life is through the use of enzymes. Acting on flour starch during the baking process, their anti-staling impact remains long after their deactivation in the oven.

Enzymes represent an important area of research for us at DuPont. Our interest in meeting cake shelf-life expectations is behind one of our latest enzyme projects.

Inspiration from bread

The inspiration for our study came from our G4-amylases, which we have used successfully to optimise and maintain the fresh-keeping quality of bread. Here, the use of G4-amylases in yeast-raised bakes with a high fat and sugar content – sweet rolls and brioche for example – has proven particularly advantageous.

This sets the scene for testing G4-amylases in cakes.               

The inhibition issue

High sugar content is typically a problem for traditional anti-staling enzymes in cake recipes. The starch-hydrolysing activity of a standard maltogenic α-amylase results in the production of maltose, a disaccharide comprising two glucose molecules. At the same time, the sucrose in cake recipes is a disaccharide of glucose and fructose. As sucrose resembles maltose, it may block the active site of the enzyme and diminish further enzyme activity.

Previous lab studies have shown that this inhibition of maltogenic α-amylase means up to 80% of enzyme activity is lost in the presence of just 5% sucrose.

Improved sugar tolerance

By contrast, G4-amylases hydrolyse starch into maltotetraose, comprising four glucose molecules. This secures a far higher sucrose tolerance, with a loss of around 10% enzyme activity in a 5% sucrose assay.

What we wanted to find out was whether the high efficiency of G4-amylases at a low dose in high-sugar bread products would also apply to cake products with a sugar content of some 20%.

Our application trials have so far included sponge cake, pound cake and high-ratio muffin recipes from markets around the world. In all cases, G4-amylases had a positive effect, not only displaying a good fresh-keeping effect, but also enhancing and maintaining the cakes’ initial softness and moistness throughout a two-month shelf life.

Sponge cakes: sensory evaluation

Sponge cakes: TPA firmness and resilience

Opportunities moving on

Depending on the water activity and pH of the formulation and cake storage conditions, microbiological problems may set in before staling becomes significant. With the addition of a suitable anti-mould solution, an opportunity exists for pushing the limits on cake shelf life even further.

We tested the POWERSoft® Cake Enzymes from the DuPont™ Danisco® portfolio.

An optimised cake recipe is not the only strategy for maximising fresh-keeping over time. If you use an indulgent fruity filling, there is another tactic you can draw on.

Here at DuPont, we call it controlled migration – the movement of a limited amount of water from the filling into the surrounding cake to maintain the feeling of moistness and softness.

The way to achieve that is by ensuring your filling has a water activity level slightly higher than that of the cake itself. Dry matter content plays a particularly important role in this regard. Knowing the water activity of your cake and filling is the first step towards migration control.

Migration on trial

For our own trials, we baked cakes with a water activity of just under 0.7. A filling with 40% fruit and less than 70% dry matter was tested  – securing a water activity just high enough to ensure the right amount of migration. Too high, and the risk is unappealing sogginess and a tendency towards rapid mould development.

Developing a filling with the right water activity is one thing, securing the right texture and stability is another. This requires the use of a hydrocolloid. In most bakery fillings, the choice lies between pectin and modified starch. Although typically the more expensive of the two, we chose pectin for its flavour release and clean-label image.

Finding the right pectin

Pectins, too, vary in their sensory and gelling properties. Our priority was to achieve the right level of controlled migration and, at the same time, a filling with the optimum fruit flavour and spreadability.

We selected two pectins – one a standard, low amidated pectin, the other a speciality product – from the portfolio we normally draw on for jam applications and compared their performance in a filling applied after baking.

Fresher over time

Our findings indicate that controlled water migration from both pectin-based fillings leaves cake feeling moister and fresher during shelf life than a control without filling.

The difference lies in the sensory evaluation. Here, our trained sensory panel found that the filling with the speciality pectin stood out for its enhanced authentic fruit taste, flavour intensity and creaminess. From a processing perspective, it was also seen to deliver improved spreadability and pumpability, easing handling during processing.

This has helped us expand our knowledge of optimised fruit fillings for cakes. But, don’t forget – it all starts with the water activity. Write to me if you need any advice.

We tested GRINDSTED® Pectin LA 410 from the standard range and GRINDSTED® Pectin SF 337 EXTRA from the speciality range.