Water - FSSAI FOOD ANALYST EXAMINATION SERIES

 

Water is a fundamental nutrient required by the human body, essential for various physiological functions and vital for survival. It makes up a significant portion of our body weight, with the average adult body being approximately 60% water. Here are some key points to consider for an exam-level post-graduate note on water as a nutrient:

Functions of Water:

·         Transport of nutrients and waste products: Water is a crucial component in the transportation of nutrients and waste products throughout the body. It acts as a medium for the movement of substances across cell membranes and through the bloodstream.

·         Temperature regulation: Water helps regulate body temperature through sweating and evaporative cooling. It also helps to dissipate heat generated during metabolism.

·         Lubrication: Water serves as a lubricant for joints, organs, and tissues, reducing friction and allowing smooth movement.

·         Metabolic processes: Water is essential for many metabolic processes in the body, including the breakdown of carbohydrates, fats, and proteins. It is also necessary for the production of energy, as well as the removal of waste products.

·         Maintenance of blood pressure: Water helps maintain blood volume and blood pressure, which is vital for overall health.

·         Hydration: Water is necessary for hydration, which is critical for maintaining a healthy balance of fluids in the body. Proper hydration is also essential for maintaining the health of organs, tissues, and cells.

Sources of Water:

Water can be obtained from various sources, including drinking water, other beverages, and foods. Fruits and vegetables with high water content, such as watermelon, cucumber, and lettuce, can also contribute to overall water intake. However, the primary source of water intake for most people is from drinking water, whether from tap or bottled water.

Requirement for Water:

The amount of water required by an individual depends on various factors, including age, sex, physical activity, and climate. Generally, it is recommended that adults consume at least 2 to 3 liters of water per day to maintain proper hydration. However, this requirement may increase in hot and humid weather or during intense physical activity. Some people may require more water intake due to specific medical conditions or medications.

Structure of Water:

Water is a simple, yet unique molecule composed of two hydrogen atoms and one oxygen atom (H2O).

·         The molecule has a bent shape, with the oxygen atom at the center and the hydrogen atoms bonded to it at an angle of approximately 104.5 degrees.

·         The oxygen atom has a partial negative charge, while the hydrogen atoms have a partial positive charge, creating a polar molecule.

 

Water Balance and Its Effects:

·         The body has various mechanisms to maintain a healthy balance of water, including thirst, hormonal regulation, and excretion. However, when the body loses more water than it takes in, dehydration occurs, which can lead to various health issues, including dizziness, fatigue, headaches, and constipation.

·         Severe dehydration can also lead to heat exhaustion or heat stroke, which can be life-threatening. On the other hand, overhydration can also be harmful, leading to hyponatremia, a condition where the blood sodium levels become too diluted, which can be dangerous.

 

Moisture is an essential component of most foods, and its presence can have a significant impact on the food's quality, texture, and shelf life. Here are some key points to consider for an exam-level post-graduate note on moisture in food:

Hydrogen Bonding:

Hydrogen bonding is the primary mechanism through which water molecules interact with each other and with other substances in food. Hydrogen bonds are formed between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of another. These bonds are responsible for water's high surface tension, which enables it to form droplets and adhere to surfaces.

Cohesion and Adhesion Properties:

Water's cohesive properties allow it to stick to itself, forming droplets and films. This property is essential in creating smooth and creamy textures in foods such as sauces and ice cream. On the other hand, adhesion properties enable water to stick to other surfaces, allowing it to wet surfaces and penetrate porous materials.

Specific Heat:

Water has a high specific heat, which means it can absorb and store a lot of heat energy without undergoing a significant temperature change. This property is essential in regulating the temperature of foods during cooking, preventing overheating and burning.

Osmosis:

Osmosis is the movement of water across a semi-permeable membrane from an area of high concentration to an area of low concentration. This process plays a crucial role in food preservation and can be used to dehydrate foods or preserve them in a solution.

Colloidal Properties of Foods:

Many food components, including proteins, starches, and fats, can form colloids when mixed with water. Colloids are mixtures of tiny particles that remain suspended in the liquid. They are responsible for many of the unique textures and properties of foods such as emulsions, foams, and gels.

 

Water- Acid-Base Balance:

Water is the most important substance for life, and maintaining a proper balance of acids and bases in the body is crucial for proper functioning of many physiological processes. The acid-base balance in the body is regulated by several mechanisms, including the lungs, kidneys, and buffering systems.

The pH Scale:

The pH scale is used to measure the acidity or basicity of a solution. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. Solutions with a pH below 7 are considered acidic, while those with a pH above 7 are basic or alkaline.

Hydrogen Ion Concentration:

The concentration of hydrogen ions (H+) in a solution is a measure of its acidity. The more H+ ions present in a solution, the more acidic it is. The pH of a solution is related to the concentration of H+ ions in the solution by the following formula:

pH = -log [H+]

Buffers:

Buffers are substances that help to maintain a stable pH in a solution by accepting or donating hydrogen ions as needed. Buffers can be either weak acids or weak bases, and they are important in many biological processes.

Henderson Hasselbach Equation:

The Henderson Hasselbach equation is used to calculate the pH of a solution based on the concentration of the acid and its conjugate base. The equation is:

pH = pKa + log [A-]/[HA]

where pKa is the dissociation constant of the acid, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid.

The Henderson Hasselbach equation is useful in determining the buffering capacity of a solution, as well as predicting the pH changes that occur when an acid or base is added to a buffer solution.