The Influence of Malt Extraction Adding to UF Fresh Low Fat Cheese on Its Textural Properties

Today , demands for reduced fat products such as reduced fat cheeses is growing as it has shown in other food products , however high nutritional value of milk fat as a functional food can't be ignored. This study deals with investigation of adding malt extract ( in 4 different concentration 0.075 , 0.1 , 0.15 and 0.2 % ) to ultra filtered cheese and comparing them with 2 control including a sample produced of milk containing 3.5 % fat and a 0.93 % fat and their rheological and textural properties evaluated at 3 , 20 , 40 and 60 days. Results indicate reduction of texture properties revealed. Rheological analysis exhibited the texture improvement by adding malt extraction; therefore this product can be use an additive to ultra filtered cheese to enhance its texture.[How to cite this article: Shafiei, Z., Hojjatoleslami, M., Soha, S., and Shariati, M.A. 2014. The Influence of Malt Extraction Adding to UF Fresh Low Fat Cheese on Its Textural Properties. International Journal of Science and Engineering, 6(1):57-60. Doi: 10.12777/ijse.6.1.57-60


Introduction
UF fresh cheese has a soft, spreadable texture produced by ultra filtration of milk to reach 35 % dry solid and then enzyme coagulation of retentate. Two month shelf life , final pH 4.8 , having 45-60 % fat in dry solid in final products are some properties of this cheese , therefore consuming it cause to increase the level of fat in consumers (1,3,15). Fat has both nutritional and textural role in cheese.And low fat cheeses contain deficits including hard and elastic texture , weak melt ability and inappropriate color and flavor (11)as a results of resulted more compressed protein matrix and more brittle cheese texture (10,16). To improve cheese texture , different ways are placed into 3 categories including modifying of usual technology of cheese making , application of suitable fat replacer to improve creaming texture and appropriate culture media which produce exopolysaccaharides (16). Miocinovic et al. studied of using Inulin in low fat ultra filtered cheese and reported that low fat cheese without Inulin contained big holes while adding it caused to a creamy and compressed texture (13). Applying Barley >-glucan concentrate as a fat replacer on physiochemical and functional properties of low-fat Mozzarella cheese exhibited more moisture and a softer texture in final products (20). Lobato-Calleros et al , used a complex of emulsion of different hydrocolloids such as Carboxymethyle cellulose, Arabic Gum and pectin. Among them CMC led to high fat texture-like properties in produced cheese (12).
Adding malt extraction to Domiati cheese resulted in a slight increasing of moisture and acidity, more lypolyse and proteolyse along with more bacterial count overall flavor enhancement and textural properties of cheese(1). This study aims at improving technological and functional properties of low fat ultra filtered cheese by adding malt extraction.

Materials and Methods
To investigate of different concentration of malt extraction, six treatment produced and coded as follows: SFC: cheese produced by whole milk contains 3.5 % fat LFS: cheese produced by milk contains 0.93 % fat without malt extraction  mm, compressed to 50 % of initial height (10 mm) in 2 cycles .penetration rate was 0.5 mm /s and each test was performed in 3 replicates .the evaluated properties were Hardness , Cohesiveness, Springiness, Chewiness , Gumminess and Adhesiveness (5,7).To perform cutting test former device equipped with a TA /53 probe and required force to cut in depth of 15 mm measured .And each samples test performed in 3 replicates. A TA /40 probes used for punching test and the required force of punching metal rod in depth of 10 mm measured. Other conditions were the same as other tests (5).Results analyzed by ANOVA and Duncan tests by SPSS V.20 software. Table 1 shows the TPA results of fresh samples. Hardness define as required force of compressing cheese between milling teeth (for hard and semi hard cheeses) or between tongue and palate ( for soft and spreadable cheeses ).Water, protein and fat influence hardness of cheese (18). Protein dominance in low fat cheese results in introducing more hardness and elastic like texture (14,16). The most and the least evaluated hardness wererelated to LFS and X4 respectively. Increasing malt extract is thought to result in reduction of hardness ( Fig  1). These results are in agreement with Romeih et al. (2002) and Koca et al. (2004). Moisture increased the plasticity of protein matrix and decreased its elasticity made it ready to be disrupted in compressing , entrapped water molecule inside of 3 dimensional protein matrix , therefore weaken and soften the texture.

Cohesiveness
Cohesiveness define as the amount of created deformation by milling teeth compressing before cutting occurs, mostly depends on molecules links (5,7,19). The most and the least cohesiveness were related to LFS and SFC respectively (p<0.05) .it is thought that due to fat reduction (4,16,17).All the results are in agreement with Volikakis et al. (2004). Weakness of inside links is the main important reason of cohesiveness reduction observed in low fat cheese which deformed irreversibly by TPA device .This reduction also can increase proteolyses and softening of cheese.

Springiness
Springiness implies the elasticity of sample in which more springiness causes to more elasticity. The most amount of this parameter related to the low fat treatment (5,19). The most amount of springiness related to the low fat treatment .results were in agreement with Koca et al , 2004; Romeih et al , ( 2002).It is found that malt extract resulted in moisture absorption , reduction of hardness and less ability to initial shape when removing force (15).

Chewiness
When fat reduced, chewiness increased significantly respect to SFC (in agreement with Volikakis et al.,2004 ).It is thought that more moisture content as a result of water binding by adding malt extract to cheese has been weakened the texture and decreased the required force of cracking samples (5,21,19). Table 2 shows the results of Gumminess test.The amounts of Gumminess in LFC was significantly more than SFC (p>0.05).This results were in agreement with Romeih et al, 2000. More malt extract, less Gumminess in produced cheese may arise from increasing moisture content 'cause of capacity of malt absorbing water (12,17,19).

Adhesiveness
The amount of adhesiveness increased by increasing fat content due to loosening of protein matrix and more water intake. Koca et al, (2004) found more cohesiveness in samples containing more fat (10). X4 showed the most cohesiveness. Similar letters describe no significant differences (p < 0.05) SFC: cheese produced by whole milk contains 3.5 % fat LFS : cheese produced by milk contains 0.93 % fat without malt extraction X1 : cheese produced by milk contains 0.93 % fat and adding 0.075 % malt extraction X2: cheese produced by milk contains 0.93 % fat and adding 0.1 % malt extraction X3: cheese produced by milk contains 0.93 % fat and adding 0.15 % malt extraction X4:cheese produced by milk contains 0.93 % fat and adding 0.2 % malt extraction Punching LFC's hardness was significantly more than SFC and other treatments (p>0.05).Adding malt extract to cheese cause to soften texture and less required force for penetrating. X4 had the least hardness among treatments (16,19). Table 2 displays the results of cutting test .as it has shown , the most and the least hardness observed in LFC (significantly differed from other treatments) and X4 respectively .