**4. Vegetable proteins and their quality**

**Figure 4** shows a wide range of vegetable-based proteins derived from several sources. These can be extracted from low-cost and ecological sources such as agricultural wastes and crop and oil industry by-products, which can help to achieve food security [16].

Because of the varied metabolic requirements of certain tissues, rats, and humans have varying amino acid requirements. The fact that the protein-energy ratio of animal proteins (or a combination of proteins) does not reach its maximum value but rises when methionine is added supports the notion that rodents have a higher sulfur amino acid need than humans. The consumption of a protein in people can be measured by monitoring the fecal matter and urine nitrogen (N) losses; it is predicated on the nitrate adjustment study premise. These studies indicated that some vegetable proteins, particularly beans and wheat, are underappreciated. Wheat's net protein utilization was calculated to be 41% when compared to egg protein. In humans, data show that most vegetable sources of protein have true digestibility in the 80–90% range, with references having lower digestibility (e.g., "rice, cereal": 75% and "rice, polished": 88%) and others having higher digestibility (e.g., "wheat, refined": 96%, "soy protein isolate": 95%). When protein percentage is purer, vegetable protein is much more digestive. Instead of looking at total nitrogen levels, per specific amino acid's digestion should be studied, as this has been suggested for many years. Because some protein acids personal digestion fluctuates or is lower than that of others for several reasons, average digestion is an insufficient proxy with each protein bioavailability.

The digestibility of various dietary proteins was found to be between 89 and 95 % in investigations using advanced techniques. The findings were 89 %–92 % for soy protein isolate, pea protein flour or isolate, wheat flour, and lupine flour, which were close to those reported for eggs (91%) and meat (90 –94 %), but somewhat lower than those published for milk protein isolate (95 %). When absorbed at a level that fulfills the entire protein needs (e.g., 0.66 g/kg weight), a dietary protein with an amino acid score offers precisely the exact quantities of proteins that satisfy metabolic requirements and at a ratio in which no amino acid limits utilization of others. Lysine in grains and sulfur amino acids in beans typically emerge as restricted AAS stands for Amino acid score of vegetable protein. A closer analysis of the literature discloses that lysine rates are reduced or near zero in cereals such as sorghum,

**Figure 4.** *Major plant-based protein sources.*

wheat, triticale (47, 49, and 62%), and rice (80%), and also low in few more both these sources (walnuts and almonds: 60%). In contrast, it is high or extremely high in other sources, notably legumes (e.g., pea: 168 %; fava bean: 152 %; soybean: 134 %) and animal proteins (milk: 168 %; beef: 193 %; egg: 160 %) [18].
