What are the functional properties of maltodextrin and its applications?

Maltodextrin is a starch derivative without free starch made from starch or amylopectin by enzymatic low hydrolysis, refining and spray drying. The raw material of maltodextrin can be starch, such as corn starch, tapioca starch, wheat starch, etc., or raw grains containing amylopectin, such as rice and corn.
Maltodextrin is a starch hydrolysis product, and the degree of hydrolysis is generally expressed as the DE value. the DE value (glucose equivalent) refers to the percentage of direct reducing sugars (expressed as glucose) in the starch hydrolysate as a percentage of the total solids. The DE value of natural starch is close to 0, while the DE value of fully hydrolyzed glucose is close to 100. maltodextrins are classified into 3 categories according to their DE value: MD10, MD15 and MD20.
Since maltodextrin is an incomplete hydrolysis product of starch, it is a mixture whose functional properties are closely related to the sugar composition (molecular weight distribution, average chain length, branching degree, etc.), and the sugar composition in maltodextrin will directly affect its sweetness, viscosity, hygroscopicity, and coloring properties.
When the DE value of maltodextrin is 4-6, its sugar composition is all larger molecules above tetrasaccharide; when the DE value is 9-12, its sugar composition contains more high molecular sugars and less low molecular sugars, so this kind of maltodextrin has no sweetness, is not prone to browning, and is not prone to moisture absorption; when the DE value is 13-17, it has lower sweetness, relatively lower proportion of reducing sugar, better solubility, and can produce suitable viscosity when applied to food; when the DE value is 13-17, it has lower sweetness, relatively low proportion of reducing sugar, and can produce appropriate viscosity; the DE value is 13-17, it has lower sweetness, and can produce suitable viscosity when applied to food. When the DE value is 18～20, it will have a slightly sweet flavor, the moisture absorption will increase, and there is part of reducing sugar, and the browning reaction will occur.
The higher the degree of hydrolysis of maltodextrin (the higher the DE value), the lower the average molecular weight, the lower the degree of linearity, the simpler the molecular structure, the lower the degree of aging, the greater the solubility, sweetness, hygroscopicity, permeability, fermentation, browning reaction, and the greater the decrease in freezing point; and the worse the organization, viscosity, stability, and anti-crystallization.
It is also due to the different functional properties of maltodextrins with different DE values that maltodextrins are widely used in a wide variety of food products, including confectionery, ice cream, pastries, beverages and convenience foods.
Maltodextrins are used as drying agents for food products.

Maltodextrin has good fluidity, no odor, good solubility, strong heat resistance, low hygroscopicity, no agglomeration, even if used in a high concentration of the state will not mask the flavor and aroma of other raw materials, has a very good carrier role, commonly used in the drying process of juice products to play the role of drying agent, so as to prevent the juice powder product agglomeration, increase the solubility of the product, improve the product organizational structure.
In the preparation of jam, juice products due to higher processing temperatures and longer processing time will affect the nutrient composition of the fruit, reduce the content of antioxidant substances in the fruit.
Studies have shown that polyphenols in fruits (such as anthocyanins) are more sensitive to temperature, and when the processing temperature is higher than 60 ℃, anthocyanins will be lost by 20% to 50% compared with fresh fruits. Therefore, how to retain the nutrients and sensory properties of fruits during processing and storage, and extend the shelf life of fruits is the focus of research.
Spray drying is commonly used in fruit processing to convert liquid into powder, which has the following benefits: spray drying shorter processing time and lower temperature is suitable for fruits containing heat-sensitive components; it is conducive to maintaining the flavor substances, color and nutrients in the fruits; made of fruit powders can reduce the volume of the package, easier to operate and transport, and extend the shelf life.
Despite the advantages of spray drying more, but fruit juice products are not easy to spray drying treatment, mainly because of fruit juice products in small molecular sugar (fructose, glucose, sucrose) content is high, will lead to spray drying particles are easy to stick and easy to stick the spray drying tower wall of the problem, reduce the thermal efficiency of spray drying.
In addition, the juice powder after spray drying is easy to absorb moisture, poor fluidity. Juice in the small molecule sugar is prone to bonding phenomenon is due to small molecule sugar glass transition temperature (Tg) is low, the lower the Tg, the easier the material will be bonded. For example, the Tg of lactose, maltose, sucrose, glucose and fructose are 101, 87, 62, 37 and 16 ℃ respectively, and their relative ease of bonding increases accordingly.
Maltodextrin, due to its higher molecular weight, lower viscosity and higher Tg, can be used as a carrier for spray drying to enhance the Tg of the overall system, thereby reducing the phenomenon of system caking and bonding.
Araujo-Díaz et al. used maltodextrin and inulin as drying aids to spray dry blueberry juice to obtain blueberry powder, respectively, and evaluated the ability of the two drying aids by the physicochemical properties of the blueberry powder and the retention of antioxidant substances. They found that there was no difference in physicochemical properties between the juice powders with maltodextrin and inulin as carriers, but maltodextrin as a carrier retained resveratrol and quercetin 3-D-galactopyranoside in blueberries more effectively than inulin.
Ferrari et al. examined the effects of maltodextrin and gum arabic as carriers on the physicochemical properties of spray-dried blackberry powder. Compared with gum arabic, blackberry powder with maltodextrin as a carrier was less prone to hygroscopicity, retained a higher amount of anthocyanins, had a stronger antioxidant capacity, had a lower water content, and had a better rehydration capacity. The blackberry powder obtained by spray drying can also be used as a natural coloring agent in a variety of foods (beverages, desserts, jellies, jams, etc.).
Maltodextrin has also been used in the drying of fruit juices such as dates, prunes, lemons, carrots, and dried fruits such as mangoes and tomatoes, all of which provide a good drying aid.
Researchers have further examined the effect of maltodextrin concentration on spray-dried fruit juices, Oberoi et al. selected different maltodextrin concentrations (3%, 5%, 7%, and 10%) for spray-drying watermelon juice, and maltodextrin was effective in alleviating watermelon powder bonding, and with the increase of maltodextrin concentration, the moisture content of the spray-dried watermelon powder was reduced but the time of re-solubilizing the watermelon powder would be be prolonged.
Negrao-Murakami et al. investigated the effect of maltodextrins with different DE values (DE10, DE15, and DE18) on spray-dried Paraguayan tea extracts, and maltodextrins with a low DE value (DE10) provided the best protection of the tea extracts during the storage period, with the best polyphenol stability and antioxidant activity.
It was also found that the moisture content of the spray-dried powder increased with increasing DE value and the time of re-solubilization grew, which could be attributed to the fact that maltodextrins with high DE values have a high degree of branching and hydrophilic groups, which are more likely to bind water in the powdered state. This finding is consistent with the study of Fazaeli et al. The lower the DE value, the better the drying effect on blackberry powder.
The previous literature mainly investigated the effect of maltodextrin on the Tg of spray-dried or freeze-dried fruits, indicating that the Tg of dried fruits would be increased with the increase of maltodextrin content, but it did not consider that the Tg would also be affected by the structure of the material and the moisture content of the material (or water activity) at the same time, and that a comprehensive consideration of the Tg curves of the drying material and the isothermal dilution curves would result in more systematic data and It can be used to predict the change rule of processing characteristics, storage characteristics and texture in the drying process of fruits.
Pycia et al. used modified starch as raw material to prepare maltodextrins with different degrees of enzymatic degradation, with the increase of DE value, the Tg of maltodextrins prepared from modified starch will gradually decrease, and the maltodextrins prepared from diastarch phosphate and acetylated diastarch phosphate (DE6) have the largest Tg when they are prepared from diastarch phosphate and acetylated diastarch phosphate.
By modifying maltodextrin or preparing maltodextrin from modified starch, the ability of maltodextrin as a drying aid to regulate the Tg of the system can be further optimized, and the customized preparation of maltodextrin with more functional properties will be the next step worthy of in-depth research.
Application of maltodextrin in embedding

Maltodextrin is one of the good wall materials used for food microencapsulation. Microencapsulation technology has been widely used in the fields of biology, medicine, food, pesticides, cosmetics and so on. Taking the microencapsulation of flavor substances commonly found in food as an example, the flavor substances are the core material, while the encapsulated material is the wall material, or known as the carrier. Generally the length of the microcapsule will not exceed 3mm, and according to the size of the embedded product can be divided into: nano-scale (1-100nm) and micron-scale (100-1000nm).
For the material embedding is very important step is to screen the wall material of microcapsules, good wall material needs to meet the following conditions: good emulsification properties and film-forming properties; low viscosity and hygroscopicity under high solids content; better protection of the core material; stability during processing and storage; no taste; low price.
Maltodextrins as microencapsulated wall materials have begun to be used in a number of different food applications, such as encapsulation of functional fats and oils, biologically active substances, flavor substances, probiotics, and so on.

Most of the literature on maltodextrin as wall material for encapsulation mainly investigated the effect of maltodextrin with different DE values on the encapsulation effect, however, no consistent conclusion was obtained.
Matsuura et al. investigated the effect of different DE values of maltodextrins (DE2, DE10, and DE25) on the embedding of hydrogenated coconut oil, and found that the coconut oil powder embedded with maltodextrins of DE10 was less stable after rehydration, which may be due to the stronger interaction between maltodextrins of DE10 and the emulsifier sucrose ester, which affects the stability of the oil powder after embedding.
Whereas, when embedding flavor substances, researchers have found that high DE values provide better embedding, longer shelf life, and reduced oxygen transmission.Sheu et al. used a mixture of whey protein and maltodextrin (DE5, DE10, and DE15) to embed ethyl octanoate using spray-drying, and they found that compared to maltodextrins with a low DE value, the dextrins with a high DE value were They found that compared to low DE maltodextrins, dextrins with high DE values were more capable of reducing the unevenness of the surface of the microcapsules after embedding, thus maintaining the functionality of the microcapsule shells, and were less susceptible to deterioration and loss of flavor during the storage period.
Although maltodextrin with high DE value has better effect on oxygen isolation and flavor release, with the increase of DE value, starch hydrolysate sweetness will be higher, it is easier to absorb moisture, and it is also easier to have Meladic reaction. Therefore, the above factors need to be considered to select the appropriate maltodextrin.
In addition, although the DE value of maltodextrin affects its functionality as a wall material, the DE value alone is not sufficient to predict the encapsulation effect of maltodextrin.
Recently, researchers have also found that the molecular weight distribution of maltodextrins is not the same for the same DE value, and that the molecular weight distribution of maltodextrins may be more accurate in determining the application properties of maltodextrins.
Due to its weak emulsifying ability, maltodextrin is also used as a wall material in combination with other wall materials that have better emulsifying ability, such as gum arabic, milk protein, and other emulsifiers.
Premi et al. investigated the effect of different combinations of maltodextrin, gum arabic and whey protein concentrate on the embedding of moringa oil and evaluated the embedding effect through the emulsion properties, embedding rate, microstructure and oxidative stability of the oil powder, and it was found that the effect of embedding using maltodextrin and gum arabic was superior to the effect of maltodextrin and whey protein concentrate, and it was further found that through the observation of microstructure The combination of maltodextrin and gum arabic was able to form a continuous and smooth surface without cracks in the microstructure of the wall of the powdered oils and fats.
Fernandes et al. used a combination of gum arabic, modified starch, maltodextrin and inulin to embed rosemary essential oil and found that the use of maltodextrin combined with gum arabic and modified starch, which had better emulsification properties, was more effective in retaining volatile substances. Similarly, the combination of maltodextrin, modified starch and gum arabic (1:1:4) was found to be more effective in protecting flavor substances than each wall material alone when embedding cinnamon oleoresin.
Application of Maltodextrin in Enhancing Functional Properties of Proteins

With the accelerated development of the food industry, the ingredient market urgently needs proteins with functional and nutritional properties as food ingredients. Therefore, on the one hand, we should vigorously develop the resources of proteins with excellent characteristics, and on the other hand, we need to modify the existing proteins to meet their special requirements in food, which is the modification of proteins.
Maltodextrin improves the functional properties of proteins mainly through the melad reaction with proteins. When the covalent bonding of proteins with maltodextrins is realized by using the Melad reaction to improve the functional properties of proteins, controlling the reaction process so that the reaction stays in the first stage is a very important key point of this technology.
The hydrophilic nature of the hydroxyl groups in the graft of protein and maltodextrin, due to the introduction of maltodextrin with polyhydroxyl groups, can lead to a significant increase in the solubility and emulsification properties of the whole molecule.
Shepherd et al. found a greater enhancement in the emulsification capacity of casein and maltodextrin graft reaction products compared to casein alone.
O’Regan et al. used maltodextrin in a meladic reaction with hydrolysates of sodium caseinate (hydrolysis degrees of 6%, 13%, and 48%, respectively), and the reaction products were able to enhance the stability of emulsions in accelerated shelf-life experiments (7 d, 45°C), and the reaction products improved the solubility of proteins at pH 4.0 to 5.5, as compared with hydrolysates of sodium caseinate without the transgenerative cross-linking reaction (increase of 10% to 50%).
Xue et al. used dry heat to prepare the melad reaction product of soybean isolate protein and maltodextrin, the solubility of the grafted soybean isolate protein at the isoelectric point was greatly enhanced, and structurally the protein structure of the grafted soybean isolate protein showed a decrease in the degree of α-helix and β-folding, and an increase in the irregular curls. The researchers also found that the reaction conditions controlling the initial melad reaction of the protein with maltodextrin were critical.
Wang et al. performed the melad reaction with maltodextrin and whey isolate proteins at different pH conditions (pH 4-7), and the high degree of grafting, low surface hydrophobicity, low isoelectric point, and high thermal denaturation temperature of the protein grafts at pH 6 resulted in the best thermal stabilization of the reaction products.
Different proteins with maltodextrins undergoing the meladic reaction can enhance the functional properties of proteins by controlling the appropriate reaction conditions, which will also expand the use of proteins in more food applications.
Semenova et al. further investigated the effect of maltodextrins with different DE values on the thermodynamic properties of soybean globulin, using different DE values (DE values of 2, 6, and 10) for the melad reaction between potato maltodextrin and soybean globulin, and found that the hydrophilicity of the protein grafts was increased more dramatically, and the surface activity decreased in the case of the reaction with maltodextrin with DE value of 10. The DE value of maltodextrin is inversely proportional to its molecular weight, and the larger the DE value, the shorter the average molecular chain length, indicating that in the grafting reaction of maltodextrin with protein, the DE value will have an important effect on the solubility and surface activity of the end product.
Mulcahy et al. investigated the properties of maltodextrin (DE values 6, 12 and 17), corn syrup solids (DE values 30 and 38) and whey protein melad reaction products using a moist heat method. The extent of grafting reaction increased with increasing DE values for the same reaction time. Maltodextrin (DE value 6) reacted better with whey protein to increase the thermal stability of whey protein in 50 mM NaCl solution.