Introductory Chapter: Pseudocereals as Subexploited Food

1. Introduction

Pseudocereals constitute a category of food comprising of non-grass plant species, which cannot be essentially classified as cereals, but have similar properties, applications, and uses to them. According to physical and botanical characteristics, pseudocereals are dicotyledonous and therefore, different from cereals, which are monocotyledonous [1, 2]. Because of their similar physical characteristics to cereals—such as their starch content, texture, palatability, and cooking method—the name “pseudocereals” is still used to describe them. Due to their extremely dense nutritional qualities and simplicity of use in farming and agriculture, quinoa (Chenopodium quinoa), amaranth (Amaranthus spp.), chia (Salvia hispanica), and buckwheat (Fagopyrum spp.) are the most grown and researched pseudocereals in current contexts.

Subexploited food could be defined as those, which were part of different populations for many years in the past and were replaced in the early twentieth century by other foods, which prevailed under contemporary contexts of consumerism and agricultural conditions. Pseudocereal crops have been explored as remedies to attain food security as subexploited food products because it is estimated that the world population will reach 9700 million of people in 2050, and they could be an alternative with potential benefits not only in terms of nutritional value but also in a socioeconomic perspective where food production is anticipated to be limited [3]. The Food and Agriculture Organization (FAO) defines food security as the state in which every individual, at all times, has physical and financial access to enough, safe, and nutritious food that satisfies their dietary needs and food preferences for an active and healthy life [4]. Within this definition, pseudocereals are viewed as a category of food products, which have a significant potential in curbing food insecurity, malnutrition, and agricultural losses due to climate change.

2. Nutritive value of pseudocereals

Pseudocereals have been described as “the grains of the twenty-first century” by the Food and Agricultural Organization due to their excellent nutritional value [5]. They are high in fiber, carbohydrates, and high-quality proteins with a composition of essential amino acids that are balanced and rich in sulfur-containing amino acids [6]. They also have minerals (calcium, iron, and zinc), vitamins, and phytochemicals such as saponins, polyphenols, phytosterols, phytosteroids, and betalains, which have purported health benefits [6].

Buckwheat, quinoa, and amaranth are rich sources of flavonoids, phenolic acids, trace elements, fatty acids, and vitamins. These groups of compounds have demonstrated and proven effects on human health, such as prevention and reduction of many degenerative diseases. Fagopyritols, a type of soluble carbohydrates, are widely present in buckwheat seeds. A significant source of D-chiro-inositol, which improves glycemic control in people with non-insulin-dependent diabetes mellitus (NIDDM), is fagopyritol [7]. The main nutrients found in buckwheat grains are proteins, polysaccharides, dietary fiber, lipids, rutin, polyphenols, and micro- and macroelements. These compounds are known to be rich sources of total dietary fiber (TDF) and soluble dietary fiber (SDF), which are used to prevent diabetes and obesity [8]. Buckwheat grains comprise abundant nutraceutical compounds, and they are rich sources of B group vitamins.

Amaranth contains a huge amount of crude fiber, protein, tocopherols, and squalene. All of which have a cholesterol-lowering function [9]. Quite possibly, the only grain that naturally balances the essential amino acids in its protein is quinoa. The presence of essential amino acids, such as histidine, isoleucine, leucine, phenylalanine, threonine, tryptophan, valine, lysine, and methionine, indicates its high quality [10]. Both amaranth and quinoa are rich in minerals such as K, Ca, P, Mn, Zn, Cu, Fe, and Na, dietetic fibers, and vitamins C and E [11].

Quinoa seeds are another excellent source of flavonoids, which are mostly glycosides of the flavonols quercetin and kaempferol [12]. The phenolic compounds found in amaranth seeds are ferulic acid, caffeic acid, and phydroxybenzoic acid [13]. Pseudocereal lipids, which are abundant in pseudocereals, include phytosterols—an important class of physiologically active substances. Because of their structural similarity to cholesterol, they are indigestible by the human gut and prevent intestinal cholesterol absorption, decreasing plasma levels of both total and low-density lipoprotein (LDL) cholesterol [14]. Quinoa seeds contain a noteworthy content of saponins. These taste bitter and contain compounds that are surface-active and have a structure made up of one or more sugar chains and an aglycone that is either steroid or triterpenoid. Saponin levels vary within the range of 0.01–4.65% with a mean value of 0.65% between different varieties of quinoa [15].

3. Cultivation of pseudocereals

Pseudocereal cultivation has expanded because of a greater understanding of their biological activities and a growing health consciousness among consumers. Global quinoa cultivation, production, and consumption have increased three times in the last six years according to observations [16]. The production of quinoa was expected at 39,000 million tons (MT) in Bolivia, 28,649 MT in Peru, and 929 MT in Ecuador in the year of 2005 [17]. Moreover, the production of buckwheat in China, Russia, Ukraine, Poland, and France was expected to reach 800,000, 605,640, 274,700, 72,096, and 124,217, MT, respectively [17]. Pseudocereal cultivation is still very uncommon, and according to FAO production data statistics, amaranth is not even registered.

Compared to conventional cereals, fewer breeding efforts have been made to maximize the use of pseudocereals in high-input farming systems. Nonetheless, there are plenty of chances to grow these underutilized food items. These crops can be effectively grown, and their worldwide production will rise, provided that the climate, length of the growing season, and quantity of arable land are all favorable. It is anticipated that thorough analysis and characterization of the germplasm would result in the development of superior cultivars possessing desired characteristics concerning food and nutritional security. New biotechnological methods, for instance, genome editing, next-generation sequencing, and whole-genome sequencing, are anticipated to provide further opportunities to enhance pseudocereal production [18]. These methods will be able to allow breeders and researchers to alter genome sequences and introduce genetic material conferring desirable traits.

Pseudocereals are touted as a panacea for the two global issues that plague humanity today. The food crisis brought on by the lately widespread coronavirus and the pandemics of obesity, diabetes, and other noncommunicable diseases. It has been determined that pseudocereals, with their significant resistance to abiotic stress, resilience to climate change, consistent yields, high nutritional content, appealing biological activities, and good edible quality, would all be important crops in the future to feed the world’s population [19]. While extensive work has been conducted on the diverse biological properties of components from pseudocereals, less is known about the range of bioactivities of peptides [20]. The study concludes that pseudocereal peptides have noteworthy nutritional advantages and hold promise as functional meals. While there have been many noteworthy advancements in the bioactivities of pseudocereal peptides, there are still certain opportunities and obstacles that should be taken into account for further research.

4. Value added products from pseudocereals

Pseudocereals are frequently utilized to make nutrient-dense gluten-free goods such as bread, pasta, and confections. Urquizo et al. [21] developed a fermented quinoa-based beverage in order to expand the traditional uses of quinoa and to provide new, healthier, and more nutritious food products. Gambus et al. [22] utilized amaranth as an alternative gluten-free ingredient to increase the nutritional quality of gluten-free bread. Bread with higher levels of fiber, protein, and minerals had an acceptable amount of amaranth flour.

5. Perspectives for the future

A lot of work needs to be done before pseudocereals can produce the intended results because their economic potential has not yet been completely understood and acknowledged. Because they are a good source of important nutrients that help reduce oxidative stress in the body, adding pseudocereals to staple diets, either whole or in combination with true cereals, can improve overall quality and lengthen life expectancy. There is still more potential to be discovered, and the industrial method to growing and processing pseudocereals needs to be addressed. The value-added products on an industrial level can be prepared using pseudocereals, and the market may be developed to combat nutrient-related malnutrition even in developed countries where the diet appears to be mostly calorie-dense.