Table 1. Theoretical and experimental value of moisture content in Tofu. Theoretical Value of Moisture Content in Tofu | Experimental Value of Moisture Content in Tofu | 84.20% to 85.65% | 81.65 % |
From the result, moisture content in tofu samples is around 81.65 %. From references, the moisture content of tofu samples from 84.20% to 85.65%. (Wang et al, 1983) The difference value of this moisture content may be caused of the error during the experiment such as the balance that been used is not accurate as well as possible or maybe the silica gel in the desiccators are already oxidized. So, the accurate value cannot be obtained. To obtain an accurate measurement of the moisture content or total solids of food using evaporation methods, it is necessary to remove all of the water molecules that we originally present in the food without changing the mass of the food. In this experiment, to analyze the moisture content of tofu, the oven drying methods are used to determine it. In oven drying methods, the mass of water is measured in a known mass of sample. The moisture content is determined by measuring the mass of a food before and after the water is removed by evaporation. Another study of students and research decisions discovered that there are some practical considerations, that is:
1) Sample dimension The rate and extent of moisture removal depends on the size and shape of the sample and how finely it is ground. The greater the surface area of material exposed to the environment, the faster the rate of moisture removal.
2) Water type The ease which water is removed from a food by evaporation depends on its interaction with the other components present. Free water is most easily removed from foods by evaporation, whereas more severe conditions are needed to remove chemically or physically bound water.
3) Decomposition of food components If the temperature of drying is too high or the drying is carried
References: McClements, D. J. (n.d.). Determination of Moisture and Total Solids. Retrieved from http://people.umass.edu/~mcclemen/581Moisture.html Wang, H. L., Swain, E. W., & Kwolek, W. F. (1983). Cereal Chemistry, Effect of Soybean Varieties on the Yield and Quality of Tofu, vol. 60, pg 247.[PDF document] Retrieved from http://naldc.nal.usda.gov/download/26009/PDF