Fruit squashes of grapes, orange, pineapple etc. can be preserved by adding:

Question

Accepted Answer

The correct option is 1:
Potassium metabisulphite (KMS), chemically represented as K₂S₂O₅, is the most appropriate and widely used chemical preservative for fruit squashes and juices, especially those that are light in color, such as grapes, orange, and pineapple. When dissolved in the acidic fruit squash, KMS releases sulfur dioxide (SO₂). This sulfur dioxide acts as a powerful preservative in two key ways, which are essential for maintaining the quality of these beverages. First, it has a potent *antimicrobial* effect, inhibiting the growth of spoilage microorganisms like yeasts, molds, and bacteria, which is crucial in high-sugar environments like squashes where fermentation can easily occur. Second, and equally important for these fruits, it acts as a strong *antioxidant*, preventing oxidative browning and color degradation that often occur when fruit pigments are exposed to air. For these light-colored fruit products, KMS is the preferred preservative as it effectively preserves the natural, bright color and fresh flavor profile without causing any undesirable changes to the product's visual appeal. Its permissible concentration is carefully controlled to ensure maximum preservation with minimum health impact.

The incorrect option is 2:
Glacial Acetic Acid is a highly concentrated form of acetic acid, typically around 99% pure. The term 'glacial' refers to its pure, anhydrous state, which is extremely potent and highly corrosive. Due to its high concentration, it is primarily used in industrial applications, as a strong chemical reagent, or as a disinfectant. While acetic acid is a preservative, using the 'glacial' form would render the fruit squash violently acidic, making it unpalatable and potentially unsafe for consumption, even in small quantities. For food preservation, acetic acid must be heavily diluted, as seen in vinegar, to be safely and palatably incorporated into a product. Therefore, its extreme strength and hazard profile make the glacial form completely unsuitable for direct food preservation in beverages like squashes.

The incorrect option is 3:
Vinegar is a dilute solution of acetic acid, typically 4% to 8% concentration, and is a safe, natural food preservative. However, vinegar's strong, pungent, and distinct sour flavor is highly incompatible with the desired sweet, fruity taste of a squash. It is successfully used to preserve foods like pickles, chutneys, and savory sauces where its characteristic sour or tangy taste is an expected part of the flavor profile. Adding vinegar to a sweet beverage like orange or pineapple squash would completely alter its intended flavor, effectively ruining the product's taste and quality. The purpose of preservation in squashes is to maintain the original fruit flavor, a goal that vinegar would directly undermine.

The incorrect option is 4:
Sodium chloride, or common table salt, is a preservative that works primarily by drawing water out of microbial cells through a process called osmosis. This mechanism requires a very high concentration of salt, which is why it is used for curing meat or preserving items in strong brines, such as certain pickles. For a fruit squash, adding the necessary high concentration of salt to achieve preservation would make the beverage excessively salty and completely undrinkable. Furthermore, salt does not possess the strong anti-oxidant properties of potassium metabisulphite, meaning it would not be able to prevent the enzymatic browning and color loss that are major concerns when preserving light-colored fruit juices. Therefore, sodium chloride is not used in fruit squashes due to its detrimental effect on both flavor and color stability.