An overview on applications of guar gum in food systems to modify structural properties

DOI:

Guar Gum or guaran is extracting from endosperm of Cyamopsis tetragonolobus (figure 1) and C. psora-loides [1]. Guar plant belongs to family Fabaceae or Le-guminaceae. Common name, is guar, from sankrist word “go” or “gav”. Guar bean contains a large endosperm rich in galactomannan, a gel forming agent in water. As depicting in figure 1 Guar gum is composed of chain (1→4) – linked β-D mannopyranosyl units substituted at O-6 by single-unit side-chains of α-D-galactopyranose (figure 3) [2]. The germ and hull of the guar seeds are called Guar meal, which is rich in protein. Figure 2 depicts different part of Guar seed.

There are some parameters effects on characteristics of Guar gum such as particle size, temperature [4].

Figure 1. Guar Cyamopsis tetragonoloba

Figure 2. Schematic of different parts of Guar seed

Figure 3. The Schematic of chemical structure of Guar Gum

Results and discussions

Increase the molecular weight and concer-tation increases the non-Newtonian behavior of guar solutions [5, 6]. It is native in India, Pakistan, united states and some parts of Sudan are the originality of Guar plant.

Guar is a plant exudate and can participate in viscosity and gelling process characteristics. A distinctive properties of polysaccharides in performance of natural systems are their hydrogen bonding potentials which makes them appropriate in useful services.

Dietary polysaccharides refer to a group with inert structure, mainly non soluble, by which some rheological and sensory characteristic of a food system modifies. Remained polysaccharides can drive compactness thickening quality etc. First time, guar found as source of gum in 1945 and started to become a global prominence crop [7].

Mostly the application of guar gum can summarize as below:

• 1.    Drying and preserving of pod for future [8, 9].

• 2.    With respect to be a high protein source, it uses as Mammals’ feeding [10].

• 3.    To cure night blindness, smallpox, enlarged liver, head swelling [11].

Rheological properties of Guar gum could be arising from random coil polymers of this gum in solutions [12, 13]. Gum behaves thixotropic and immediately forms a high viscous solution in cold water [14].

In addition, stability of guar gum in acidic condition is reasonable the lowest possible pH found to be stable is 2 at 25 °C [9]. Indeed, guar gum is a kind with a wide range of food applications such as ice cream, meat and dairy products. Some roles of Guar which has found suitable in food systems are reduction of chewiness, prevention of ice growth, enhancing organoleptic and sensory properties [10]. High viscosity makes guar suitable in case of bakery products in which moisture retention influenced by while in frozen foods it prevents synersis [15].

Ice cream, a food product with superiority of being normal healthy, easy digestibility and a good source of Vits [16] indicates a pseudo plastic behavior. [17].

Certainly, guar gum plays in improving of ice cream in both consistency and viscosity. It also aids the stabilization while changing in flavor [18, 19].

In cold water, guar gum swells and its technical degree depends on the rate of thickening and final viscosity. Guar gum is commonly considerable as a locust bean gum replacer. The main difference arises from their interaction to viscosity; Guar dissolves in cold water, whereas locust bean gum needs cooking for reaching to Max of viscosity [7].

Overall, guar gum gives a time, concentration and temperature dependent viscosity. up to a 0.5% concertation of guar gum we can see a linear Newtonian like behavior while in more concentrations pseudo plastic flow gives a concept of molecular interactions [20, 21].

The amount of 0.1–1.15% of Guar gum to finished cake creates better icing and frosting along with more moisture retention during shelf life. Guar gum causes that bakery products have a more integrate structure as well as yields to an easy slicing texture with no crumbling. Salad dressing also can be formulated by addition of guar gum owing to its high binding capacity. Guar gum also can prevent migration of food constituents mainly fat, controlling of WHC [7].

Guar can increase the viscosity of the aquatic phases followed by reduction in separation rate of W/O phases [22]. Since beverage is processing under cold conditions therefore solubility of guar in cold water is a point which along with resistance at low pH conditions consider a precedence. In order of beverage a 0.1–0.15% of weight can be sued [7]. Table 1 has summarized recent studies on the guar applications in food industries.

Table 1.

Application of guar in food industries

The type of food	Application of Guar	References
Beverage	control viscosity as well as to reduce calories	23
Pet food	As dietary fiber and is safe for a wide range of animal	24
salad dressings, sauces, relishes, ketchups and canned soup	Control glazing. Blooming and moisture retention	25
frozen food and meat products	Binding properties	26
Ice cream	Enhance structural characteristics and reduction of crystal growth	26, 27
Low fat yogurt	Reduction of synersis	26
Bakery products	dough yield and inhibit synersis	28
Dairy products	thickener	29
chapati	Create softness	30
Fried products	Reduction of oil uptake	31
cake	As fat replacer	32
Sausage	Impart softness	33
Tomato ketchup	Enhancing of consistency	34