Investigating the effects of addition of zedo gum on physicochemical, sensory, rheological and colorimetric properties of low salt Ashi noodle

Flour products are one of the most widely used food products in all over the world. Various types of pastry products derived from wheat flour are including the varieties of soup, plumura, and cane produced by traditional and semi-industrial methods. They are categorized in the bread and cereal group. The place of wheat- flour dough products, including Ashi noodle in the food basket of Iranian households, is gradually being consolidated. This product is a mixture of wheat flour, water and salt after the treatment process by the machine before being dried. The high consumption of salt in the Ashi noodle leads to the development and progression of hypertension in addition to increasing the risk of cardiovascular disease and, on the other hand, reducing salt leads to problems such as loosening and loss of Ashi noodle drying, as well as the degradation of the strand when boiling. Hydrocolloids or gums are compounds creating consistency and texture and increasing stability, acting as emulsifiers, forming gels, and improving oral sensation.

The general objective of this study was to investigate the effects of adding Farsi gum extract at concentrations of 0.2, 0.4, 0.6, 0.8, 1 and 1.2% based on the weight of flour instead of the salt used in the control group of the Ashi noodle (4.5%) on the rheological properties of Ashi noodle, as well as the evaluating physicochemical, texture, colorimetric, qualitative and sensory properties of low salt Ashi noodle one day after production. Zedo gum is a clear gum leaked from mountain almond trees. Zedo gum is found in white, light yellow, yellow vegetable, orange yellow, red and brown, in various sizes and forms. This gum is also composed of Arabinose and Galactose units. It is also known as Shirazi gum. Therefore, seven treatment groups and a control group were designed according to a completely randomized design. In order to analyze the data, Duncan’s method was used at 95% significance level in mini-fever software.

The results of rheological tests of dough with aloe vera revealed that salt reduction and increased gum significantly (p≤0.05). Those rheological properties of the aqueous pulp which were influenced were including mean curve height, mean curve length, inflation index, and mean surface under the curve, configuration test, and elasticity. The physicochemical results showed that by adding gum and reducing salt content. The amount of moisture was increased and the amount of ash and salt decreased significantly. The results of texture test were determined by texture analysis analyzer. By reducing salt, increasing the concentration of gum, and the hardness of the treatments, the decreasing trend and adhesion rate increased, with the highest adhesion ratio for gum samples 1 and 2. There was no statistically significant difference in the level of adhesion, elasticity and gumminess. The results of colorimetric tests with Hunter lab showed that there was no statistically significant difference in the color components a*, b⃰ and L* between all treatments with the control sample. In evaluating the qualitative characteristics of Ashi noodle, it was shown that by reducing the amount of salt to 3.90% and adding gum to the concentration of 0.6% of the weight of the heterogeneous strands, the weight of the broken and degraded strands showed a decreasing trend compared to the control; and in the concentrations higher than 0.6% gum, these incremental changes showed a statistically significant difference between the samples with 1.2% gum and the other treatments. Moreover, the results of sensory evaluation indicated that there was no significant difference compared to the control sample by reducing the amount of salt to 3.90% and adding 0.6% gum to smell, color, texture and overall acceptance of treatments. The taste score of all treatments did not differ significantly from the control sample. The results of this study showed that the amount of Ashi noodle salinity could be reduced to 0.6%, and instead, gum can be added to it with no effect on the qualitative, textural and sensory properties of the Ashi noodle compared to the control sample.