Abstract
Humans meet their nutritional requirements by consuming food, and our body uses naturally sufficient amounts of all necessary nutrients to maintain its functioning. Proteins form the basis of the human diet because they are necessary for immune responses, cell signals, muscle masses, and the repair of damaged cells. Animal and plant food products are the main protein sources in the human diet. Based on scientific evidence, proteins derived from animals recently started to be replaced by plant-based options as prefered proteins for a range of reasons. Consumption of non-meat protein sources being shown to be healthy and environmentally friendly is a major consideration. Plant-based protein is helping minimize high cholesterol, type 2 diabetes, high blood pressure, obesity, certain types of cancer, including colorectal, ovarian, and breast cancers, and a diet based on non-animal proteins could increase life expectancy and decrease greenhouse gases emissions from livestock as less resources are used for plant production. The chapter describes the nutritional benefits and current uses of nine non-animal protein sources and the health benefits arising from replacing animal protein.
TopIntroduction
Nutrients play a crucial role in maintaining overall human health. Protein is the most important nutrient required for growth and development (Besler, Rakıcıoglu, Ayaz, Demirel Büyüktuncer, Özel, Samur Eroğlu, … & Yürük, 2015). The structure and function of our bodies, the regulations of cells, tissues and organs depend on proteins. Approximately 16% of the adult human body is composed of protein. As proteins in the body do not form storage depots, we need to get enough of them daily through a balanced diet. Proteins are long chains of amino acids, which are their building blocks created, formed and synthesised for our human body to function correctly. Although the properties of the amino acids vary between animal and plant sourced proteins, they both can supply the needed and recommended daily requirement for protein of 0.8 g/day, considered sufficient for almost all healthy adult individuals (Pasiakos, Agarwal, Lieberman, & Fulgoni, 2015).
Protein sources in a diet come from animal and vegetable sources (Lin, Lu, Kelly, Zhang, Zheng, & Miao, 2017). Common examples of animal protein sources are meat, poultry, fish and eggs, and common examples of plant–derived proteins are beans, lentil and soybean (Nehete, Bhambar, Narkhede, & Gawali, 2013). In the majority of industrialized countries, the main protein source of dietary protein is animal foods. However, increased consumption of red meat and processed meat along with other animal products has been shown to be associated with obesity, coronary heart disease, high blood pressure, cancer, elevated serum and urinary uric acid levels (Møller, Sluik, Ritz, Mikkilä, Raitakari, Hutri–Kähönen, … Raben, 2017). Because of the adverse effects of animal protein on health, vegetable protein sources seem to be a wise alternative in meeting proteins needs. Vegetable protein sources are increasingly being recommended because of their positive effects on health (Chen, Song, Chen, Ding, Peng, & Mao, 2016; Comerford & Pasin, 2016; Wu, Zeng, Huang, Li, Zhang, Ho, & Zheng, 2016). In order to provide human protein requirements, it is necessary to support the production of plant proteins which can replace the sources of animal protein (Comerford & Pasin, 2016). Vegetable proteins can meet the essential amino acids that people need (López, Galante, Robson, Boeris, & Spelzini, 2018). Such sources are known to provide greater saturation than animal protein sources because of their low energy content and high fibre content (Nielsen, Kristensen, Klingenberg, Ritz, Belza, Astrup, & Raben, 2018). It is known that consuming foods with high fibre content enhances insulin sensitivity and provides glycemic control (Moorthi, Vorland, & Hill Gallant, 2017). There is also evidence that the risk of cardiovascular diseases can be reduced by a flexitarian dietary model which involves the consumption of more vegetative proteins rather than a meat–rich diet (Richter, Skulas–Ray, Champagne, & Kris–Etherton, 2015).
This chapter presents an evaluation of the nutritional properties and the many human health advantages of nine important plant–derived proteins obtained from beans, soybean, chickpea, lentil, quinoa, buckwheat, chia, teff and spirulina in term of their physiological benefits. Amino acid composition, nutritional aspects, functional properties and their role in promoting good human health are examined. Although these plants are well-known, only recently nutritionists started drawing attention to them as superfoods and alternatives in meat replacement.
Key Terms in this Chapter
Spirulina: A biomass of cyanobacteria (blue-green algae) that can be consumed as food or nutritional supplement.
Soybean: Annual Asian legume ( Glycine max ) widely grown for its oil-rich proteinaceous seeds, for forage and soil improvement.
Lentils: A high-protein pulse, widely cultivated in Eurasian countries, an annual leguminous plant ( Lens culinaris ) with flattened edible seeds.
Chia: An annual edible plant ( Salvia hispanica ) of the mint family, native to South America, and used for its nutritional values; its seeds are predominantly used as a food source.
Quinoa: A plant of the goosefoot family originally found in the Andes, where it is widely cultivated for its small, edible, starchy, ivory-colored seed, which is used as a food staple.
Nutritional Physiology: Deals with the study of nutrients, their role in the growth and health of different types of food and their effect on methabolism.
Plant-Derived Proteins: Foods obtained from plant sources, including vegetables, whole grains, nuts, seeds, legumes, and fruits, with no animal products.
Beans: Edible, nutritious, widely grown seeds of various plants of the legume family, especially of the genus Phaseolus , usually oval or kidney-shaped.
Teff: An African cereal native to Ethiopia, cultivated as a staple food crop, for flour and used for making traditional fermented breads.
Chickpea: A round yellowish edible seed ( Cicer arietinum ), a legume of the family Fabaceae , widely used as a pulse.
Buckwheat: An edible plant ( Fagopyrum esculentum ) with high nutritional properties cultivated for its triangular grain-like seeds used as a food source.