Introduction
Hydrocolloids and emulsifiers are both food additives, but they have different functions. Hydrocolloids are substances that thicken, gel, or stabilize foods, while emulsifiers help mix immiscible substances like oil and water.
Hydrocolloids
Are substances that, in aqueous solution, form a colloidal system, increasing viscosity or forming gels.Their main function is to modify the consistency of foods, making them thicker, creamier, or gelatinous. They can also stabilize emulsions or suspensions, preventing phase separation.
Some examples of hydrocolloids: agar-agar, modified starches, beta-glucans, carrageenans, pectin, carob seeds, bamboo fibers, potato fibers, pea fibers, gelatins, gum arabic, xanthan gum, guar gum, and inulin. In which products are they most likely to be found: baked goods and pastries, biscuits, ice cream, yogurt, sports drinks (especially maltodextrin
Emulsifiers:
They are molecules that have a hydrophobic (fat-loving) portion and a hydrophilic (water-loving) portion. This structure allows them to stabilize emulsions, which are mixtures of immiscible liquids such as oil and water. Emulsifiers sit between the two phases, reducing surface tension and preventing separation. Common examples include lecithin, mono- and diglycerides of fatty acids, and polysorbates.
In short, while hydrocolloids modify the overall texture of a food, emulsifiers work specifically to keep emulsions stable, preventing the separation of oil and water. Some hydrocolloids, such as lecithin, can also have emulsifying properties.
Hydrocolloids
A -Hydrocolloids enable products with long shelf lives, the inclusion of whole grain flours and fiber, the absence of trans fats, and, last but not least, the absence of gluten. Hydrocolloids are molecules capable of binding water in large quantities; among the most commonly used in baked goods are xanthan gum, pectin, modified cellulose, and fructo- and galacto-oligosaccharides. Some of these substances are considered dietary fibers, capable of stimulating a feeling of satiety and having positive effects on intestinal function. Hydrocolloids often achieve their technological-functional effect in the product even when added to dough in small quantities, for example, less than 1% of the total powdered ingredients. In bread dough and other baked goods, hydrocolloids help improve dough workability during production thanks to their rapid and uniform hydration. The volume, structure, and softness of the finished products are improved.
Fragility is reduced, for example, in the case of “foamy” baked goods with a high presence of air bubbles or suspended particles (chocolate, fruit, or nuts): these bubbles or particles are stabilized within the system thanks to hydrocolloids. During storage, the shelf life of the products is also increased by maintaining their softness for longer periods: the difference compared to products without hydrocolloids becomes more evident as time passes. Finally, it appears that the presence of hydrocolloids is also able to influence the size of ice crystals within bread dough or other semi-cooked products during freezing, resulting in a higher-quality thawed product (Reference H1).
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There are unit operations that are difficult to implement for foods that do not involve the use of gluten, such as the extrusion, drawing, or lamination phases that occur in pasta or some baked goods. The stresses that occur in these phases require elasticity in the dough, therefore, formulations capable of withstanding the continuous processing of a perhaps pre-existing plant are essential (Reference H2).
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Comparing gluten-free crackers, we find extremely simple formulations, with corn and rice flours, and more complex ones, with the addition of potato starch, dextrose, emulsifiers, and thickeners. From a nutritional standpoint, it’s clear that the food may be richer in sugars and some fats than the same conventional product. Sandwich bread, more difficult to make because it’s leavened, features rather complex formulations based on corn, rice, or buckwheat, starches, vegetable fibers, proteins, sugars, thickeners (including hydrocolloids), emulsifiers, and acidifiers. This recipe implies, nutritionally, either an increase in carbohydrates of approximately 10-15% compared to the conventional product in the same category, or an increase in fats, especially saturated fats, of approximately 30-50% (Reference H3).
In the confectionery sector, the considerations are more or less the same, since from a nutritional point of view, compared to conventional products, they remain higher values of carbohydrates, especially sugars, and fats, mainly saturated, to compensate for the lack of viscoelasticity of the protein part. Prodotti e tecnologie per alimenti senza glutine. Macchine alimentari – Anno XVII -1 – Genn. Feb 2015
B – The food industry has been committed to providing consumers with high-quality rheological properties along with healthy and nutritious food products (Goff & Guo, 2019; Manzoor, Singh, Bandral, Gani, & Shams, 2020). Consequently, recent years have seen the widespread use of food hydrocolloids in the formulation/reformulation of various food categories, the production of functional foods, and innovation initiatives (Manzoor et al., 2020). Food hydrocolloids are considered crucial food components due to their improvements in viscosity, gelation, and thickening, enhancing the rheology and sensory properties of foods (Saha & Bhattacharya, 2010; Goff & Guo, 2019). The terms gum and mucilage may also be used interchangeably with hydrocolloids. Regardless of what they are called, these ingredients are generally found in industrial applications as viscosity improvers, emulsifiers, coating agents, gelling agents, stabilizing agents, and thermodynamic stability providers (Goff & Guo, 2019; Maity, Saxena e Raju, 2018; Manzoor et al., 2020) (Fig. 1).
They find functional applications mainly in food products, including confectionery (glazing agents, texturizers), specific beverages (emulsifiers), dairy products (thickeners and stabilizers), pastries (bulking agents, sensory quality and shelf-life improvers), and frozen fruits and vegetables (cryoprotectant) (Maity et al., 2018; Salehi, 2020; Viebke, Al-Assaf, and Phillips, 2014). Recently, food-grade hydrocolloids have reached the forefront due to their health benefits and significant pharmaceutical, as well as food, applications. Furthermore, their potential health effects and the mechanisms of their dietary intake have been studied.
Recent literature has indicated that dietary hydrocolloids play crucial roles on the gut microbiota due to their diverse physicochemical or structural properties (Tan & Nie, 2021). Some of these important roles are their prebiotic impacts, stimulating the production of short-chain fatty acids (SCFA), reducing gastrointestinal discomfort as well as preserving normal intestinal function (Marciani et al., 2019; Viebke et al., 2014; Williams & Phillips, 2021, pp. 3–26), an increase in viscosity within the intestinal lumen, a reduction or increase in the absorption of some nutrients (Nybroe et al., 2016), lower cholesterol (Manzoor et al., 2020; McClements, 2021), a decrease in hyperglycemia (Lu, Li, & Fang, 2021) as well as normal body weight regulation (Johansson, Andersson, Alminger, Landberg, & Langton, 2018; Viebke et al., 2014). Furthermore, research on hydrocolloids and intestinal modulation appears to be expanding day by day thanks to cutting-edge multi-omics technologies and detailed analysis of the human microbiome. This article provides a comprehensive overview of specific dietary hydrocolloids, particularly those with a polysaccharide structure in intestinal modulation, and their potential interactions with nutrition and health.
A comprehensive review on food hydrocolloids as gut modulators in the food matrix and nutrition: The hydrocolloid-gut-health axis. al. 2023. https://doi.org/10.1016/j.foodhyd.2023.10906