Defensin-like protein | |||||||
---|---|---|---|---|---|---|---|
Identifiers | |||||||
Organism | |||||||
Symbol | ? | ||||||
UniProt | P56552 | ||||||
|
Pentadin, a sweet-tasting protein, was discovered and isolated in 1989, in the fruit of oubli ( Pentadiplandra brazzeana Baillon ), a climbing shrub growing in some tropical countries of Africa. [1] Sweet tasting proteins are often used in the treatment of diabetes, obesity, and other metabolic disorders that one can experience. [2] These proteins are isolated from the pulp of various fruits, typically found in rain forests and are also used as low calorie sweeteners that can enhance and modify existing foods. [2]
Pentadin and brazzein were discovered in 1994, and are the 2 sweet-tasting proteins discovered in the African fruit, Pentadiplandra brazzeana . [3] Pentadiplandra brazzeana consists of a red outer-shell that contains three to five seeds inside of it, which are covered by a layer of red pulp that contain brazzein and pentadin, sweet tasting proteins. [3] Pentadiplandra brazzenna Baillon bears red berries that are about 2 inches in diameter and contain the sweet tasting proteins, Brazzein and Pentadin, as discussed above. Brazzein and Pentadin are extracted from the same fruit however Pentadin is extracted from the fruit after it is heat-dried and Brazzein is extracted from the fresh form of the fruit. [4]
The fruit has been consumed by the apes and the natives for a long time. The berries of the plant were incredibly sweet African locals call them "j'oublie" (French for "I forget") because their taste helps nursing infants forget their mothers' milk. [6]
Sweet tasting proteins have been known to exist for many years and indigenous people have been known to use these proteins as a way to add sweetness to their foods without the use of other sweetening agents, such as sucrose. [7] The sweetness of Pentadin has been estimated to be about 500 times more than Sucrose, when looked at on a weight basis. [7]
The molecular weight of Pentadin is estimated to be 12kDa and has a sweetening ability of 500 times moe than sucrose. This sweet tasting protein is known to resemble monellin on a sweetness basis and is higher than thaumatin. [8]
Pentadin is the second protein discovered in Oubli ( Pentadiplandra brazzeana) and is similar to Brazzein, the first protein discovered from Pentadiplandra brazzeana . More structural analysis has been done on Brazzein than on Pentadin and it is difficult to understand the particular structure of Pentadin however, some of the structural properties of Brazzein can be applied to Pentadin. Brazzein contains two regions that are particularly critical for the sweetness of the protein, the N- and C- terminus of the protein, and a region of the protein that contains the flexible loop around Arg43. The exact properties for Pentadin are unknown, however we can apply particular regions of the N- and C- terminus regions to the structure of Pentadin as they are both derived from the same fruit (Pentadiplandra brazzeana). [9]
There are six sweet-tasting proteins - pentadin, thaumatin, monellin, mabinlin, brazzein, and curculin - all of which are isolated from plants in tropical forests. These proteins show no similarities in a structural or homologous sequence aspect. All of these sweet tasting proteins have different molecular lengths, with no sequence homology and little to none structural homology. Efforts to identify structural similarities among sweet tasting proteins included using the 3D structures and DALI to find similarities. However only a vague resemblance was found for the three proteins tested, monellin, thaumatin, and brazzein. [10] Brazzein and thaumatin invoke respinses in humans through the T1R2-T1R3 receptor and can be applied t Pentadin a Brazzein and Pentadin are similar to one another. These repsonses in the T1R2-T1R3 receptor are similar to the small molecular weight sweeteners that include popular sweeteners. [10] Proteins cannot generally stimulate taste receptors like sugar normally does, however the identified sweet tasting proteins, such as monellin, thaumatin, pentadin, curculin, and mabinlin are able to interact with one's taste receptors to create a sweet taste. Very low concentrations of these sweet tasting proteins are required for them to interact with our receptors, therefore they are also known to be low calorie sweeteners. [11]
The amino acid composition of pentadin contains: [1]
Studies that have been conducted on the electrophoretic profile of pentadin revealed the presence of subunits that were joined together by disulfide bonds in the mature protein structure. These studies were done with and without the presence of 2-mercaptoethanol. [8] The more prevalent amino acids found in Pentadin are aspartic acid, glutamic acid, tyrosine, lysine, and proline, with proline being the most dominant amino acid. [4] The structure of Pentadin consists of subunits that are coupled by disulfide bonds and it is soluble in water. Pentadin can also withstand temperatures of 100 °C when exposed to it for 5 hours. The strength of the protein remains the same when it is exposed to temperature at and below 100 °C for an extended period of time (≤ 5 hours). [4]
The six sweet-tasting proteins can be used as a natural low-calorie sweetener to replace certain sugars. They are also good for the response of insulin in people who are diabetic. [12] Sweet tasting proteins can be used as naturally occurring low calorie sweeteners due to them having more sweetness and a lower calorie value than Sucrose. [13] Pentadin is a naturally occurring form of a low-calorie sweetener and can be used as a substitute for commonly used sugars, such as sucrose, glucose, and fructose. [4]
There is a growing interest surrounding low calorie sweeteners due to the average American consuming approximately 17 teaspoons of sugar on a daily basis. The recommended amount of sugar consumed for men is 9 teaspoons and 6 teaspoons for women and with these increased amounts of sugar consumption, numerous health issues increase (high blood pressure, cardiovascular diseases, and increased risk of obesity). [8] Sweet tasting proteins are being introduced as alternatives to other forms of sweeetening agents because they are also known to contain health benefits. [8]
There are two forms of sweeteners available: natural sweeteners and artificial (synthetic) sweeteners. Natural sweeteners are derived from plants and these include Brazzein, Pentadin, and Thaumatin. [14] These compounds provide sweetness with little to no calories however the long term effects of these natural proteins have not been studied intensively to accurately determine the adverse effects that may be caused. [14] Some researchers have identified that these naturally derived sweet tasting proteins may cause weight gain and insulin secretion when consumed for long periods of time. [14]
A link between chronic diseases, such as cardiovascular diseases, diabetes, hypertension, and obesity and excessive sugar consumption has been developed over the years. Increased sugar consumption causes an increase in energy intake leading to increased weight gain and chronic diseases. [14] Due to an association between sugar consumption and chronic diseases, it is important to understand that there are sugar substitutes that one can use. Many sugar substitutes are available in the market today, however more research is required to determine whether or not sweet proteins, such as Pentadin, are safe for human consumption over extended periods of time.
Sweet tasting proteins and taste modifying proteins, such as Pentadin and Miraculin, are being used as safer alternatives to normal table sugar due to their low caloric intake. All of these sweet tasting proteins are isolated from fruits and contain no unpleasant aftertaste, however the nature of these proteins don't allow for mass production like we can do with artificial sweeteners. [15]
Aspartame is an artificial non-saccharide sweetener 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide with brand names NutraSweet, Equal, and Canderel. Aspartame was approved by the US Food and Drug Administration (FDA) in 1974, and then again in 1981, after approval was revoked in 1980.
Sucralose is an artificial sweetener and sugar substitute. As the majority of ingested sucralose is not metabolized by the body, it adds no calories. In the European Union, it is also known under the E number E955. It is produced by chlorination of sucrose, selectively replacing three of the hydroxy groups—in the C1 and C6 positions of fructose and the C4 position of glucose—to give a 1,6-dichloro-1,6-dideoxyfructose–4-chloro-4-deoxygalactose disaccharide. Sucralose is about 320 to 1,000 times sweeter than sucrose, three times as sweet as both aspartame and acesulfame potassium, and twice as sweet as sodium saccharin.
Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed by the gut directly into the blood of the portal vein during digestion. The liver then converts both fructose and galactose into glucose, so that dissolved glucose, known as blood sugar, is the only monosaccharide present in circulating blood.
A sugar substitute is a food additive that provides a sweetness like that of sugar while containing significantly less food energy than sugar-based sweeteners, making it a zero-calorie or low-calorie sweetener. Artificial sweeteners may be derived through manufacturing of plant extracts or processed by chemical synthesis. Sugar substitute products are commercially available in various forms, such as small pills, powders, and packets.
Thaumatin is a low-calorie sweetener and flavor modifier. The protein is often used primarily for its flavor-modifying properties and not exclusively as a sweetener.
Diet or light beverages are generally sugar-free, artificially sweetened beverages with few or no calories. They are marketed for diabetics and other people who want to reduce their sugar and/or caloric intake.
Monellin, a sweet protein, was discovered in 1969 in the fruit of the West African shrub known as serendipity berry ; it was first reported as a carbohydrate. The protein was named in 1972 after the Monell Chemical Senses Center in Philadelphia, U.S.A., where it was isolated and characterized.
Miraculin is a taste modifier, a glycoprotein extracted from the fruit of Synsepalum dulcificum. The berry, also known as the miracle fruit, was documented by explorer Chevalier des Marchais, who searched for many different fruits during a 1725 excursion to its native West Africa.
Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones, and sugar alcohols. Some are sweet at very low concentrations, allowing their use as non-caloric sugar substitutes. Such non-sugar sweeteners include saccharin and aspartame. Other compounds, such as miraculin, may alter perception of sweetness itself.
Brazzein is a protein found in the West African fruit of Oubli. It was first isolated by the University of Wisconsin–Madison in 1994.
D-Psicose (C6H12O6), also known as D-allulose, or simply allulose, is a low-calorie epimer of the monosaccharide sugar fructose, used by some major commercial food and beverage manufacturers as a low-calorie sweetener. First identified in wheat in the 1940s, allulose is naturally present in small quantities in certain foods.
Dioscoreophyllum volkensii, the serendipity berry, is a tropical dioecious rainforest vine in the family Menispermaceae. It is native throughout most of tropical Africa from Sierra Leone east to Eritrea, and south to Angola and Mozambique. It grows at low altitudes, from sea level up to 400 m. Some authors separate plants from above 200 m as a separate species D. cumminsii (Stapf) Diels.
Curculin or neoculin is a sweet protein that was discovered and isolated in 1990 from the fruit of Curculigo latifolia (Hypoxidaceae), a plant from Malaysia. Like miraculin, curculin exhibits taste-modifying activity; however, unlike miraculin, it also exhibits a sweet taste by itself. After consumption of curculin, water and sour solutions taste sweet. The plant is referred to locally as 'Lumbah' or 'Lemba'.
Pentadiplandra brazzeana is an evergreen shrub or liana that is the only species assigned to the genus Pentadiplandra, and has been placed in a family of its own called Pentadiplandraceae. It produces large red berries, sometimes mottled with grey. It is known from West-Central Tropical Africa, between northern Angola, eastern Nigeria and western Democratic Republic of Congo. The berry is sweet in taste due to the protein, brazzein, which is substantially sweeter than saccharose. Brazzein may be useful as a low-calorie sweetener, but is not yet allowed as a food additive in the United States and the European Union.
Mabinlins are sweet-tasting proteins extracted from the seed of mabinlang, a plant growing in Yunnan province of China. There are four homologues. Mabinlin-2 was first isolated in 1983 and characterised in 1993, and is the most extensively studied of the four. The other variants of mabinlin-1, -3 and -4 were discovered and characterised in 1994.
T1R2 - Taste receptor type 1 member 2 is a protein that in humans is encoded by the TAS1R2 gene.
Taste receptor type 1 member 3 is a protein that in humans is encoded by the TAS1R3 gene. The TAS1R3 gene encodes the human homolog of mouse Sac taste receptor, a major determinant of differences between sweet-sensitive and -insensitive mouse strains in their responsiveness to sucrose, saccharin, and other sweeteners.
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with the sense of smell and trigeminal nerve stimulation, determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas, including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste.
Added sugars or free sugars are sugar carbohydrates added to food and beverages at some point before their consumption. These include added carbohydrates, and more broadly, sugars naturally present in honey, syrup, fruit juices and fruit juice concentrates. They can take multiple chemical forms, including sucrose, glucose (dextrose), and fructose.
A sweetened beverage is any beverage with added sugar. It has been described as "liquid candy". Consumption of sweetened beverages has been linked to weight gain, obesity, and associated health risks. According to the CDC, consumption of sweetened beverages is also associated with unhealthy behaviors like smoking, not getting enough sleep and exercise, and eating fast food often and not enough fruits regularly.