An innovative gel, a substitute for palm oil and hydrogenated fats

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A team from the Italian University of Udine investigates the possibility of effectively substituting palm oil and hydrogenated fats used in the baked goods industry with a monoglyceride gel.

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Sonia Calligaris, researcher at the University of Udine

Fats are a key element of products baked in the oven. Their contribution is crucial for developing the correct structural features, softness and lubrication of the final product. On an industrial level, margarine and palm oil are the most frequently used fats, but – for different reasons – both are very much the subject of consumer concerns. Margarines, for instance, contain large quantities of hydrogenated fatty acids, which according to various studies increase levels of LDL-cholesterol (the so-called “bad” cholesterol) while depressing HDL-cholesterol levels (good cholesterol). Palm oil, for its part, raises concern for the presence of saturated fatty acids, associated with adverse effects on health, and in particular, an increased incidence of cardiovascular diseases. For this reason, the European Commission sets a limit to the intake of these fats in a balanced diet (20 g/day, less than 10% of daily calories) as reported in the European Regulation 1169/2011 that has just entered into force. Palm – whose oil is used for the production of biofuel – cultivation methods are indicted due to their high impact on the environment. The need of extending oil palm plantations, in fact, led to the deforestation of vast forest areas, and the relevant habitat loss of several species that are already threatened with extinction. Furthermore, some studies relate palm cultivation with a possible increase of greenhouse gas emissions. A research team of the Department of Food Science of the University of Udine is investigating the possibility of effectively substituting palm oil and hydrogenated fats presently used in the baked goods industry with a monoglyceride gel. The studies involved various food products and, since fats interact with other ingredients with variable results on the physical properties of the final products, different types of gel and different qualities of oil were investigated in order to find the best solutions (sunflower seed oils, extra virgin olive oil, linseed oil, and castor oil were tested). The results so far are encouraging: in bread, for instance, the replacement of saturated fats with monoglyceride-based gels and sunflower seed oils did not lead to declining quality. Similar results were obtained also in the production of sponge cake. In this case, using the same gel instead of palm oil, allowed to obtain a product with the same properties of marketed goods, but with a lower content of saturated fats (reduced by 81%). We have asked Doctor Sonia Calligaris, a researcher at the University of Udine and member of the team engaged in these studies, to explain the results and their possible applications.

Which are the general objectives of your research?
From the technological point of view, the fats presently used in the baked goods industry provide quality, softness, texture and taste. They are an excellent substitute of butter which, from the industrial point of view, is too expensive to be sustainable. Margarines have been the first butter substitutes, and they still represent a widespread alternative in the US; however, they contain hydrogenated fats, which means a high amount of trans fatty acids. In several Countries, including the United States, the content of trans fatty acids in food is regulated and, if present beyond a certain threshold, there is the obligation to list them in the label. In Europe, palm oil is more widely used, which is free of trans fatty acids but contains saturated fats. From the nutritional point of view, the objective should be to reduce the use of saturated and hydrogenated fats while promoting the use of unsaturated fats (like olive oil and other plant oils), and our research is within this context. There are also major environmental problems linked to palm oil, and many supermarket chains are trying to eliminate it from their products. This might be a major decision, even from this point of view.

Lebensmittelindustrie Keksherstellung / food production

Which are the advantages you obtained using the oil types you have selected?
The use of liquid fats does not only reduce the amount of saturated and trans fats, but it can decrease the amount of total fats in the product. It is quite obvious that every commercial product has distinctive characteristics and, to obtain them, specific formulations must be defined.

In your research you mainly focused on baked goods: with which results?
It has been proven that monoglyceride-based gels can replace fats rich in saturated fatty acids, like palm oil or hydrogenated fats. We conducted tests on differently structured oils. For instance, we talk of hydrogel in case of a ternary system that contains water next to oil and monoglycerides, and of oleogel when the gel is obtained from liquid oil. According to the product, within which you want to substitute palm oil or hydrogenated fats, the use of hydrogel or organogel can be considered. In the case of bakery products, such as bread, biscuits, etc., hydrogel has always proved the best solution; with organogel the product has a tendency to harden in a short time, finds it hard to rise, and the final structure is not excellent. Organogel, in any case, may be more suitable for other productions, as for example the production of sweet anhydrous creams; but it has been used also as fat substitute in sausages and salami.
Among the different types of oil that you tested, which one has performed best?
The tests we carried out on bakery products revealed that different types of oil may be used. Obviously, every lipid matrix has specific properties that affect the quality of the final product. Sunflower oil prices, for instance, are consistent with the baking industry (palm oil is widely used for its low cost and high technological performances). But even olive oil can be used with success, however at higher costs. Wishing to provide the product with Omega 3 essential fatty acids, even flaxseed oil can be used. Hence, according to the kind of final product, the most adequate preparations and components must be evaluated.

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Are there any critical points in the use of these substitutes?
There is the expectation that the shelf-life of these products may be reduced, since they contain unsaturated oils, which are more oxidizable than saturated ones. In-depth studies should be performed on this issue, in order to develop specific assessments.
The production of these hydrogels is already practicable at industrial scale, or an additional scale-up will be required?
The study has been conducted at laboratory level. The industrial implementation has not been approached yet, and in that phase specific technological complications may emerge. It should be reminded that monoglycerides are already used in food products as emulsifiers, and are already specified in the sector’s regulations. For this reason this solution might be easily implementable at industrial level. Outside Europe there should be some application examples already, especially as substitutes of hydrogenated fats.

Is it a sustainable solution even from the economic point of view?
Yes, even from this point of view there should not be insurmountable obstacles, because monoglycerides have a low cost and their implementation should not be too burdensome. It is quite obvious, however, that liquid oils (e.g. extra-virgin olive oil) are generally more expensive than palm oil.

Which further developments are foreseen for these studies?
Research is aimed at finding new molecules acting as oil gelling agents, and there are several potentially interesting applications. Close attention is devoted to these issues and ongoing research activities are carried out in this field. Scientific literature already reports of several molecules suitable for gelling liquid oils, which may be successfully used in the food industry. For their potential, these new solutions are also called “the fats of the future”. At the University of Udine, for instance, we have studied the application of phytosterols as gelling agents, plant molecules that contribute to reduce LDL-cholesterol levels.