CONTENTS:

• Vitamins and minerals and temperature
• Cook
• Bake
• Fry
• To use the microwave or not to use it?
• Vitamin losses in sample dishes

Most of us are aware that preparing hot meals involves the loss of certain vitamins and minerals from food. Depending on how the food is prepared, these losses can be greater or lesser. Review your meal preparation methods to minimize the loss of the beneficial properties of the products.

Vitamins and minerals and temperature

Individual nutrients are known as retention factors . This refers to the average amount of an ingredient that remains in the food after heat treatment. Vitamins are among the most heat-sensitive food ingredients. Folate, vitamin C, and B1 (thiamine) are subject to the greatest losses. In comparison, the fat-soluble vitamins A, D, E, and K, as well as vitamin B3 (niacin), and vitamin B12, are relatively stable. Minerals , on the other hand, are the least sensitive to temperature. Normally, around 90% of their original amount is retained. The exception is when dishes are prepared using broth, when lower retention factors are observed because soluble minerals are lost.

These data refer to culinary processes performed in a traditional manner. The use of modern catering equipment allows for the reduction of nutrient loss . One example is the frying of fish without fat in dishes with a thermo-thermal base, i.e., made of high-quality stainless steel. This allows for better preservation of most nutrients, including fatty acids and vitamins.

Cook

Cooking is a process that significantly reduces their amount in a dish . Nevertheless, it is worth using it in the kitchen. Boiled dishes are easily digestible, and their preparation does not contribute to the formation of harmful byproducts, as does frying. In addition, cooking dishes such as soups without draining the broth minimizes the loss of water-soluble minerals. This is where proper cooking techniques are important. To reduce the loss of vitamins and minerals, start by boiling vegetables and fruits. It is also worth steaming from time to time and making sure that the products are not overcooked – the longer the processing time, the greater the losses.

Bake

Baking is a relatively useful food preparation process. This way, you can prepare healthy meals . However, this depends on the temperature used and processing time. Traditionally, we bake at a temperature of 170 to 250 degrees. However, slow baking methods with a temperature of 110–120 degrees are becoming increasingly popular. It usually takes a few hours (even up to 8!), but allows you to retain more nutrients. Some ovens are also equipped with the option to bake up to 300 degrees. It is used to prepare dishes such as homemade pizza. The lower the baking temperature, the more nutrients we can retain in the dish.

Fry

The least beneficial method of thermally processing food is deep-frying. Fried foods are usually heavy and high in calories. Let's face it: deep-frying gives dishes a unique flavor, and we can afford it every now and then. However, it's worth taking care to do it in the least harmful way. Vitamin and mineral losses during frying and baking are similar. The difference lies in the fat used and the type of frying . While baking requires little to no fat, frying usually uses a lot of it. It's worth reducing this amount by investing in good, fat-free pans. Also, be careful not to exceed the temperature, which causes the fat to smoke . This leads to the formation of compounds with toxic properties that are very harmful to health. It's also important to use the right fat when frying and not to fry twice in the same fat.

Microwave – to use or not to use?

Another thermal treatment method is microwave heating (dielectric heating). The microwave directs the energy of the electromagnetic field into the interior of the product and converts it into heat, effectively overcoming both the penetration barrier and the thermal conduction barrier of the food product. Despite the "bad reputation" of microwave ovens, studies show that microwave heating has no negative effects on proteins and minerals compared to conventional thermal processing methods. Similar, and in some cases even lower, losses have been observed for vitamins : vitamins B2, B3, and vitamin C – up to 20% loss. Vitamin B1 (thiamine) has been shown to be more influenced by the applied temperature than by the heating method.

Vitamin losses in sample dishes

Depending on the type of dish, cooking time, and cooking methods used, the loss of vitamins and minerals varies. The following table shows the vitamin retention factors for some foods depending on the method of preparation . For example, when potatoes are boiled, only 25% of the vitamin C remains in them. Potatoes themselves would be a good source of vitamin C, as they contain more of it than a lemon. However, the need to boil potatoes means only negligible amounts remain in them. It is also worth paying attention to folate, as we lose about half of it during thermal processing.

*with broth infusion
Source: H. Kunachowicz, “Nutritional value of selected foods and typical dishes”