Food Dryers and their Role in Food Conservation and Preservation

Drying removes the moisture from the food material through conduction, convection, and radiation. Foods such as fruits and vegetables have high moisture content, and considering the perishable nature of fruits and vegetables, it is necessary to preserve them. There are several types of drying methods, like vacuum drying, solar drying, and air drying. But in recent years, introduction to efficient and reliable drying techniques have come up like combined microwave vacuum drying, infrared drying, and ultrasound freeze-drying that preserves properties such as texture, color, taste, and flavor of dried products.

These novel methods of drying can be broadly classified into natural and artificial methods of drying. The natural drying process utilizes solar energy to remove the moisture content in the food, depending on weather conditions. Simultaneously, artificial methods using mechanical or electrical equipment and can remove a large amount of moisture efficiently.

Prominent Artificial Drying Methods –

Convective Drying

The convective drying method is done with the application of heat in equipment to remove water from the food substances. Through providing and transferring the heat to the food, the moisture is removed.

Drying by Radiation

Microwave radiation gives electromagnetic radiation to heat-sensitive components of the food utilizing an electric and magnetic field. It takes lesser amounts of time and temperature to remove the moisture content in foods. This drying technique also can be combined with other methods of drying, such as vacuum drying. Infra-red drying can dry various agricultural commodities, including carrots, sweet potato, and tomato.

Freeze Drying

With the freezing method and removal of solvents associated with direct sublimation, freeze-drying on foodstuffs occurs. Because of the unavailability of liquid water during freezing, you get a superior quality end product where microbes' reactions are entirely stopped. Most fruits are used in freeze-drying as it can rehydrate due to salt concentration and break down pectin cells in the membrane. In freeze-drying, the rehydration is rapid because foods' organoleptic property is almost similar to the fresh product. For extended storage periods, antioxidants and colorants are used to protect the aroma and yield a tough product.

Natural Drying Methods

Solar Drying

Sun, the free source of energy is utilized for the drying of foods since ancient times. The food is kept to be dried for several days to achieve the desired moisture content. It is the most popularly used method of Food Dryer since it is simple and only requires sunlight.

Using a solar dryer, farmers can dehydrate their produce without adding any preservatives to keep the produce nutritious and up to food safety and quality standards. Solar drying eliminates the need to hire an expert to install the dryer and also does not need electricity to operate. Additionally, it retains the nutrients, aroma, taste, and colour of the product. Thus, farmers can preserve their foods for more than six months and sell their produce when high rates. These solar drying Food Dryers play an essential role in the conservation and preservation of foodstuffs.

Over the years, we have seen research and development in Solar Dryers and Solar Air Heating systems such as -

• Solar Fish Dryer - Typically used for drying fish and kinds of seafood.

• Fruits & Vegetables Solar Dryer – Used for drying agricultural products for better preservation, long term storage, and exports.

• Spirulina Dryer - Spirulina, a sort of algae but supposedly a good source of protein and other nutrients, is dried to create niche products for specific requirements.

The Role of Food Dryers in Future Opportunities of Conservation and Preservation

Looking ahead, we can see an increase in the incomes of farmers because solar dryers help reduce food waste as it is more affordable than other dryers. But there is a need for further development of cost-effective and energy-efficient methods of drying where fruits and vegetables can be preserved. The consumers more appreciate the combinations of natural drying techniques as it reduces deterioration in fruits and vegetables. These solar dryers lessen the cost but are much easier to use than the artificial method of drying. In the future, we could see more research on developing natural drying solutions with greater efficiency to achieve a fair and effective result with minimal resource utilization.