The Nutritional Composition and Health Benefits of Fresh Fruits and Vegetables

Freshly harvested fruits and vegetables are primarily composed of water, which constitutes a significant percentage of their weight. This water content varies widely among different types of produce, ranging from 65% in persimmons to a remarkable 96% in cucumbers. Besides water, fruits and vegetables are predominantly low in protein and lipids while being rich in carbohydrates, making them essential components of a balanced diet. They also provide a plethora of micronutrients, including vital vitamins and minerals such as vitamin C, potassium, and folate, which are crucial for maintaining overall health.

Notably, most fruits and vegetables have low lipid content, with a few exceptions. Avocado and olives are unique among commonly consumed produce, containing up to 15% lipids. These lipids are primarily present in the form of cell membrane components, which play a critical role in maintaining cellular integrity and facilitating various metabolic reactions. Unlike other food sources such as oilseeds—cottonseed, palm, peanut, and soybean—avocados and olives are categorized as fruits and vegetables despite their higher lipid content.

The lipids in fruits and vegetables are often unsaturated fatty acids, which contribute to the fluidity and function of cell membranes. These unsaturated fats are beneficial for heart health, reducing inflammation, and improving cholesterol levels. Therefore, including a variety of fruits and vegetables in one's diet not only provides essential hydration and nutrients but also supports metabolic health and cellular function through their lipid content.

In summary, the primary chemical makeup of fresh fruits and vegetables is water, with a low presence of proteins and lipids but a high carbohydrate content. Their rich micronutrient profile and the beneficial unsaturated lipids in certain fruits like avocados and olives make them indispensable to a healthy diet.
The Nutritional Composition and Health Benefits of Fresh Fruits and Vegetables

Food processing effects on nutritional quality

The basic food preservations methods used by early man are still utilized today.

These and other methods are listed below:
Heat processing: blanching, canning, pasteurization
Drying
Freezing
Fermentation
Milling
Use of microwave ovens
Irradiation
Use of food additives
Nutrient addition
Packaging and storage

An analysis of these processing techniques reveals both favorable and unfavorable effects on nutritional quality.

On positive side, heat processing destroys anti-digestive factors such as trypsin and amylase in cereal grains, peas, and beans, thus improving the bioavailability (digestibility) of the proteins and carbohydrates in the products.

Heat processing also destroys thiaminase, which destroys thiamin in fish, shellfish, brussels sprouts, and red cabbage, and destroys the avidin and other factors in raw eggs white that would otherwise bind biotin and make these nutrients biological unavailable.

Heat processing increases the digestibility of starch and protein by gelatinization and denaturation, respectively and it increases the bioavailability of niacin which is present in many cereals in a bound form.

Heat processing also increases the palatability of food, resulting in increased appeal and nutrient consumption.
Food processing effects on nutritional quality