Today's fast-paced consumer constantly strives to find a delicate balance between work and personal life. Products that save time are a boon for this generation. Gone are the days when people cherished their daily grocery shop visits to buy fresh foods. The food industry's innovations and advancements have given consumers many options to manage their busy lifestyles. One of the most popular of these is frozen food. As one of the oldest means of food preservation, man has used freezing since the Paleolithic and Neolithic times to cool food. The technology was known in Italy, Spain, and India in the sixteenth century. Today, successful freezing can preserve food almost in its original state, allowing its preservation and transport worldwide.

Available throughout the year, frozen foods offer unrivaled convenience to consumers. They allow flexibility in preparing meals and enable consumers to choose healthy foods. Owing to their popularity, food companies worldwide are being pushed to expand their range of frozen food and focus on its quality and safety aspects.

What foods are usually frozen?

Foods that contain an appreciable amount of water are ideal for microbial growth and hence need to be preserved by freezing. Engineered foods like ice cream, in which a water/ice mixture is added to impart texture, are also frozen. Some other foods that are frozen include bread (28-46% water content), doughs (5-20% water content), fish (50-80% water), meat (35-90% water), vegetables (55-90% water), fruits like strawberries and raspberries (87-90% water) and ready meals (50-85% water).

Freezing of meat and fish

For industrial processing, meat is usually frozen as carcasses, boned-out primal, or quarters. Usually, meat is frozen twice before reaching the consumer. Before turning meat into products like fillets, steaks, burgers, and convenience meals, the frozen raw material is thawed and tempered. Meat and fish may be frozen by circulating air in refrigerated rooms, contact freezers, cryogenic freezing, air blast freezers, tunnel freezers, fluidized bed freezers, and brine freezing.

Freezing of fruits and vegetables

Dehydrofreezing, immersion freezing, and the addition of antifreeze proteins are techniques used to freeze fruits and vegetables. As a pre-treatment, blanching is carried out for enzyme deactivation.

Freezing of bakery and dessert products

Consumers love freshly baked products, and with the reduced availability of skilled bakers, the industry has developed Bake Off Technologies (BOT). BOT helps keep the time-consuming operations at the industrial level while the final preparation is done in small shops with minimum equipment and minimally skilled personnel. The three key technologies under this system include partially baked frozen bread, unfermented frozen dough, and partially baked unfrozen bread.

Desserts that contain dairy ingredients, including ice creams, frozen yogurt, sherbets, and sorbets, are frozen using a scraped surface freezer. Other desserts that can be frozen include cakes, pies, starch-based or gelatin-based puddings and custards, sweetened whipped toppings, raw and prepared fruits, and more.

Nutritional aspects of frozen foods

According to research, freezing is less destructive than other methods. Generally, frozen foods retain their vitamin and mineral content and the carbohydrate, fat, or protein content is unchanged during freezing. However, extended frozen storage leads to losses in water-soluble vitamins like vitamins B and C, which has a more significant impact on the nutritional value of the products.

During storage, frozen foods may deteriorate in fluctuating time-temperature environments. Most international regulations mandate maintaining a temperature of −18◦C from producer to consumer to ensure optimal quality.

Emerging freezing processes

High-pressure freezing

Non-thermal food processing techniques are currently being viewed with great interest in the food industry. Among them, high-pressure processing can preserve food with minimal heat treatment. This almost completely retains fresh foods' nutritional and sensory attributes, with no impact on their shelf life. Other benefits include short freezing times, retention of freshness, color, flavor, texture, vitamin C loss prevention, and minimal heat damage issues. Japan is at the forefront of this technology, with jams and fruit juices processed by this method.

Dehydrofeeezing

It is a method in which food is dehydrated till a desired moisture level is achieved and then frozen. Products that are dehydrofrozen could lower the packaging, distribution, and storage costs and maintain product quality comparable to conventional products. Some products where this technique is applied include kiwis, strawberries, apples, melons, potatoes, carrots, and peas. All the products showed better or better final consistency than conventionally frozen products.

Magnetic resonance freezing (MRF)

An MRF system comprises a normal freezer and a special magnetic resonance device. First, the food undergoes continuous magnetic wave vibrations and then, after a suitable product-specific period, the magnetic fields are abruptly removed. This method offers benefits like protection of tissue integrity, avoiding cracks, and fine ice structure in foods. At present, this technique needs further proof and tests before being adopted in the food industry.

Frozen foods and food safety

Almost any food can be frozen except eggs in shells and canned food. Once the food is out of the can, it can be frozen. Concerns regarding the safety of such foods often arise in consumers' minds. Foods frozen at -18℃ will always be safe because freezing slows down the movement of molecules, leading to microbes entering a dormant stage. However, prolonged storage in the freezer may impact its quality. Some key factors to be kept in mind to ensure food safety in frozen foods are given below

• To maintain freshness and quality and retain vitamins, color, texture, and flavor, all foods must be frozen at -18℃

• It is safe to freeze poultry and meat in their original packaging. If torn, they can be over-wrapped and frozen for long-term storage and to prevent freezer burn

• If freezer burn has occurred, food becomes dry in spots but is not unsafe. Heavily freezer-burned foods must be discarded due to quality issues

• Foods must be frozen as fast as possible to maintain quality and should only be stacked when frozen solid.

Frozen foods offer a safe and convenient option for incorporating healthy foods into our diet- from fruits and vegetables to whole grains, protein, and dairy. Besides saving time, frozen foods are a boon for those with limited utensils and kitchen areas. They can be a way to reduce food waste while being easy on the pocket. With the current lifestyle of consumers, the frozen food industry is set to grow in the coming times. The future cool way to live will be to freeze, thaw, cook, and enjoy!