Moisture content evaluation is very important in food industry in order to ensure the quality and required standards of food products. Basically the shelf life is highly related to the moisture proportion present in foods.
Water content calculation can also help assessing the foods mostly with respect to the texture, flavor and appearance to achieve better sensory evaluation.
Carrying out processing foods will require scientific knowledge including moisture estimation to determine food properties and their reactions during various processing such as freezing, packaging, heating, etc.
Microbiologically foods are susceptible to microbial load in presence of considerable amount of water. Some certain foods are dried to ensure protecting and extending their stability against bacteria; hence the need to conduct experiments to identify correct amount of moisture.
Chemically there are several methods to estimate water percentage including distillation and oven drying.
Distillation method – it is generally based on Dean-Stark procedures in which a weighed sample added to a flask containing solvents with high boiling point, less density than water and immiscibility in water such as toluene.
The content of flask is discharged through a condenser where it is subsequently distilled to a burette like distillation tube; solvent which is immiscible and lower density stays on the top phase and the water remains at the bottom phase. Solvent returns to the original flask (through an inclined tube linked between the burette and the fractionating column at the top of the flask). Quantity of the collected water is then directly read on the graduated burette and proportionally calculated to work out the percentage of this value.