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Why Does the Food Industry Need Fat Mimetics?

Miguel Ângelo Parente Ribeiro Cerqueira* and Lorenzo Miguel Pastrana Castro

INL-International Iberian Nanotechnology Laboratory, Braga, Portugal
* Corresponding author

1.1.1 The Role of Lipids in Foods and Human Nutrition

The human brain has a high energy demand and thus the brain uses more energy than any other organ. It is also evident when comparing other mammals, or even primates, that humans' distinctive nutritional needs are a consequence of the evolution of humans brain size. Thus, humans require fat-dense diets to supply energy needs. Fatty acids provide more than twice the calories per gram of proteins or carbohydrates; on the other hand, higher amounts of polyunsaturated fatty acids are essential to brain development (Leonard, Snodgrass, and Robertson 2010; Lehner et al. 2021). Since this evolution happened in a fat scarcity environment, humans developed the remarkable ability to detect and metabolize high-fat foods as well as the capacity toward a strong preference for the smell, texture, and taste of lipid-rich foods (Leonard, Snodgrass, and Robertson 2010).

Nowadays, in the diets of people dwelling in developed countries, there is no scarcity of fat anymore, and lipids (fats and oils) are present in the composition of many processed foods where they play important technological, nutritional, and sensorial roles. Their nutritional value is related to essential fatty acid composition and to their role in the absorption of liposoluble vitamins such as vitamins A, D, E, and K. On the other hand, the intake of these molecules increased in recent decades. Consumption of monounsaturated and polyunsaturated lipids is related to health benefits. However, in some western populations, large intakes of saturated and trans fatty acids are responsible for serious health issues linked to non-communicable diseases (NCDs) such as obesity, diabetes, and cardiovascular diseases (Te Morenga and Montez 2017; Astrup et al. 2019). These findings lead to a demand for new solutions that can guarantee the presence of healthy lipids in foods while the foods' functional properties are maintained.

The functionalities of solid fats and liquid oils in foods are very diverse; this diversity comes from the fats' and oils' physical and chemical properties. Their capacity to form emulsions is essential for producing salad dressings, mayonnaise, gravies, and cheese sauces. Emulsions also modify the flavor and texture of many foods; for example, ice cream's creamy texture is the result of an emulsion. The melting point of solid saturated fats or liquid oils determines the temperature behaviour of products such as chocolate or ice creams, respectively. Fats and oils in the shortening process are also responsible for tenderizing baked products. Some optical properties of foods, such as the opaque or glossy appearance of milk, are also due to fat. Fats and oils dissolve and preserve flavors while playing an important role in making foods satisfying or making us feel full. Finally, fats and oils are used to transfer heat and to facilitate crust formation during frying. Those functionalities are difficult to mimic; thus, the replacement of fats in foods has been a challenge among researchers and the industry. In the last 20 years, there has been an increase in new solutions within the marketplace, and there have been new developments within the scientific community.

1.1.2 Current Status of Fats in the Food Industry

The use of lipids in food formulation is widespread. Lipids are present in ingredients added to foods (normally in minor amounts), or they are added directly to foods in the form of vegetable oils or animal fat. Foods such as margarine, bakery products, chocolates, and spreads are some foods where lipids are used. One of the most commonly used strategies to change lipids' properties is hydrogenation, where the liquid fats are converted into solid and semi-solid fats with the aim of achieving different functionalities. In the past, partially hydrogenated vegetable fats were used to improve the physical properties of food products, however, several studies have shown trans fatty acids (TFAs) that result from the hydrogenation process have harmful effects on human health, showing that partially hydrogenated vegetable fats are one of the primary sources of industrially-produced TFAs in foods. As a result, in 2015, the Food and Drug Administration (FDA) determined that partially hydrogenated oils, the main source of artificial trans fats in processed foods, are not generally recognized as safe (GRAS). They gave the companies until 1 January 2020 to stop distributing food containing partially hydrogenated oils (FDA 2018). Also, the European Commission (EU) limited the use of trans fats, limiting the presence of 2 grams per 100 grams of total fat; in this case, the trans fats naturally occurring in the fat of animal origin are not included (European Commission 2019).

As an alternative, the industry started using saturated fatty acids (SFA), which can be obtained by fractionating oils, such as palm oil. Palm oil is one of the most used sources of fats for foods due to its low price, texture and rheological properties, high stability against oxidation. and good storage time. However, due to the high amount of saturated fats in palm oil, high consumption of palm oil can lead to some health problems. Studies showed that the consumption of saturated fats (except for stearic acid) influences cholesterol levels in the blood and leads to cardiovascular diseases (Zhu, Bo, and Liu 2019). The World Health Organization's current guidelines for a healthy diet mentions that reducing the amount of total fat intake to less than 30% of total energy intake helps prevent unhealthy weight gain in adults; further, the risk of developing non-communicable diseases (NCDs) is lowered by a) reducing saturated fats to less than 10% of total energy intake; b) reducing trans fats to less than 1% of total energy intake; and c) replacing both saturated fats and trans fats with unsaturated and polyunsaturated fats (WHO 2020). The European Union has also promoted healthier foods by allowing food producers to have a nutrition claim on their products' labels. This nutrition claim is related to a food product's particular beneficial nutritional property that can be related to energy or to a specific compound present in the food product. There are eight nutrition claims directly related to fats, namely: 1) low fat, 2) fat-free, 3) low saturated fat, 4) saturated fat-free, 5) source of omega-3 fatty acids, 6) high omega-3 fatty acids, 7) high monounsaturated fat, and 8) high polyunsaturated fat (European Commission 2022).

In addition to the health issues related to the consumption of some fats, there is a huge concern, among the entire food industry, related to the environmental impact of oil production. According to the Food and Agriculture Organization of the United Nations (FAO), global livestock production makes up 14.5% of all anthropogenic (human-caused) emissions, i.e. 7.1 gigatonnes of carbon dioxide (CO2) equivalent per year (Gerber 2013). In the case of lipids, one of the great examples is palm oil, where some studies revealed the considerable impact of lipid production on deforestation and the release of CO2 (Meijaard et al., 2020). In this regard, the use of fat mimetics (that can be based on other vegetable oils) can bring some new insights and possibilities to the industry.

Therefore, the removal of hydrogenated fats and the suggested limitation on the consumption of saturated fats has been changing how the food industry looks at lipids. There is a real need for healthier, trans fatty acid-free, stable, and solid-like fats, which maintain their structure at ambient temperatures, assuring a longer shelf-life. One of the solutions are the fat replacers that can be divided into fat substitutes, fat mimetics, or fat extenders, depending on their chemical composition and physical behaviour. Fat mimetics are one of the most studied alternatives, where the use of physically structured oils (oleogels) seems to be one of the most promising routes. This is related to the way they are produced, mostly using only food ingredients and without chemically modifying the lipids, thus presenting some benefits towards the sustainability and clean label trend. But also, other fat mimetics based on proteins and carbohydrates have shown their applicability and are already used in several commercial products.

1.1.3 Food Trends and Fat Mimetics

In 2017, FAO pointed out several food trends (FAO 2018). Some of those are related to the increasing population, the dietary transition in low- and middle-income countries, diet-related diseases and sustainability. Also, consumer engagement has been seen by several stakeholders as a food trend, where a consumer's behaviour and perception have a massive impact on the future direction of the agri-food system and companies' decisions. Consumers are looking for healthy and more natural products, alternative proteins, and products that can be considered clean label and sustainable. Therefore, the industry needs new technologies and strategies to answer those demands. One of the strategies can be fat mimetics; for example, the use of fat mimetics can guarantee the reduction of unhealthy fats or/and their replacement by mono- and polyunsaturated fats and, simultaneously, offer technical functionalities similar to fats.

Plant-based foods and meat alternatives are also food trends that fat mimetics strategies can greatly impact. While proteins and hydrocolloids are already used to develop those...