عنوان مقاله [English]
Background and objectives: Increasing awareness about disadvantages of consuming fatty acids in dairy products has been led to increase in consumer demand for low-fat dairy products, including cheese. Low-fat cheeses are poor in taste and their texture is rubbery and hard. Therefore, in this study, the effect of adding sesame and walnut powder with concentrations of 3%, 5% and 7% as alternative for fat in Cheddar cheese on physicochemical characteristics of Cheddar cheese was examined during 30 days of storage at 12 °C.
Materials and Methods: Therefore, seven treatments were designed along with two control samples which were low-fat Cheddar cheese and high-fat Cheddar cheese. The percentage of fat by Gerber method, the percentage of total protein by Kjeldahl method, the percentage of total dry matter by Oven method and measure of acidity by Titration method, and pH by using pH meters were calculated. Texture hardness test was performed by texture evaluation machine. The identification of fatty acid components was performed by using gas chromatography (GC).
Results: The effect of sample components and storage time on physicochemical features of Cheddar cheese samples was significant. On the first day of production, the full fat control samples had the highest and the low fat control samples had the lowest amount of fat, also sample containing a mixture of 3.5% sesame powder with 3.5% walnut powder had the highest and full fat control sample had the lowest amount of protein content. At the end of the storage period, the highest and the lowest percentage of moisture were belonged to the low-fat control sample and the sample containing 7% walnut powder, respectively. Also, the highest and the lowest content of dry matter percentages were belonged to samples containing 7% walnut powder and low-fat control sample, respectively. The highest percentage of acidity was related to full fat control sample and the lowest percentage was related to low fat control sample. The highest and lowest levels of pH at the end of the storage period were belonged to samples containing 5% and 3% sesame powder respectively. The highest and lowest levels of hardness texture were belonged to low-fat control sample and high-fat control samples, respectively. After the full fat control sample, the sample containing 7% walnut powder showed the lowest hardness texture. The results of the composition of fatty acids showed that the samples containing walnut and sesame powder contained essential fatty acids and polyunsaturated fatty acids such as omega-3 and omega-6 were higher than control samples.
Conclusion: Among the tested samples, the treatment containing 7% walnut powder was identified as superior treatment for nutritional and qualitative characteristics due to having a higher percentage of linoleic acid and linolenic acid and sensory and textural properties close to full fat control treatment.