Introduction

Hunger is a widespread and growing phenomenon, and billions of people suffer from severe malnutrition in Asian, African, and Latin American countries (1). There is a nearly 20-year difference in the life expectancies of rich and poor nations. Apart from caloric needs, there is a severe shortage of food materials, such as fruits and vegetables, tubers, root crops, and fruit nuts, which are the most important plant foods to supply humans with many of their nutritional requirements, including minerals, vitamins, proteins, starches, fats, and sugars. They provide crude fiber and bulk as well as a variety of flavors and odors. Vegetables, with the increasing recognition of their value in the human diet, are gaining commercial importance (1).