Sensory Evaluation of the moisture content has a vital importance in the food industries today. It is mainly carried out to make sure that the quality standards are met by the food products that are being manufactured. The proportion of moisture is intermittently related to the shelf life of the food products.
This Sensory Evaluation mainly helps measure the flavor, texture and appearance of the food products. To carry out this evaluation a certain level of scientific knowledge of how to estimate moisture is a must. This helps determine the properties of the food products and also to judge as to how they will react when processes such as heating, freezing or packaging are being carried out.
Many food products are easily susceptible to microbial contamination when water is present in a considerable amount. These foods are dried thoroughly as this ensures that they are protected against micro-organisms. But this can only be done once it is determined that what amount of water can be dangerous for the product in question.
Now there are many steps that need to be completed before the actual Sensory Evaluation of a food product. One of them is to estimate the water percentage. This is done with the help of various chemical processes such as oven drying or distillation.
When the Dean-Stark distillation process is employed, a weighed sample of the food product is added to a flask that contains some solvents whose boiling point is considerably high; are of a low density as compared to the water and cannot mix with water. An example of one such solvent is toluene.
All the contents of the flask are then discharged by passing them through a condenser. It is in the condenser that these contents are actually distilled in a distillation tube. The solvent toluene remains t the tom as it is immiscible while water is seen to remain in the bottom phase of the tube. The solvent is then made to return to the original flask that contained it with the help of an inclined tube that is linked between the fractioning column and the burette or distillation tube. Then the quantity of the water is measured using a graduated burette and then, proportionally, the percentage of work value is calculated.