It is well known that the world population is increasing at an incredible pace; subsequently, worldwide food production without compromising the ecosystem is an enormous challenge for the global community. From the beginning of human civilization, meat plays a vital role in acquiring proteins and other nutrients. Despite the indispensable part of the meat in the human diet, it is also considered a critical factor in environmental alterations, greenhouse gas emissions, animal welfare, and land water usage. The excessive use of natural resources and extensive animal production causes greenhouse gas emissions, which triggered reduced meat consumption and the need for more novel meat alternatives. To overcome the extraordinary demand for red meat, the phenomena of meat alternatives or meat substitutes evolved. Subsequently, meat analogs express a higher trend with low cost, safe consumption, and meaty structure and texture. Meat substitutes are predominantly vegetable centered food products that comprise proteins from pulses, cereal, microorganisms, and other fillers and flavorings mediators. Moreover, Meat products with texturized vegetable protein, mushroom, wheat gluten, pulses are considered an excellent source of as a substitute for animal protein. Additionally, mycoprotein had an impressive profile, including higher protein, low fat, health-promoting agents, with good taste and texture. However, there remains a gap in research articles focusing on the regular consumption of meat substitutes. In the current review, an attempt has been made to summarize various types of meat substitutes, different protein sources, production preparation methods, nutritional, functional properties, including current and future perspectives of meat alternatives.

Kjeldahl method used in many materials from various plant parts to determine protein contents, is laborious and time-consuming and utilizes hazardous chemicals. Near-infrared (NIR) reflectance spectroscopy, a rapid and environmentally benign technique, was investigated as a potential method for the prediction of protein content. Near-infrared reflectance spectra(1100-2400 nm) of coarse cereal grains(n=100 for each germplasm) were obtained using a dispersive spectrometer as both of grain itself and flour ground, and total protein contents determined according to Kjeldahl method. Using multivariate analysis, a modified partial least-squares model was developed for prediction of protein contents. The model had a multiple coefficient of determination of 0.99, 0.99, 0.99, 0.96 and 0.99 for foxtail millet, sorghum, millet, adzuki bean and mung bean germplasm, respectively. The model was tested with independent validation samples (n=10 for each germplasm). All samples were predicted with the coefficient of determination of 0.99, 0.99, 0.99, 0.91 and 0.99 for foxtail millet, sorghum, millet, adzuki bean and mung bean germplasm, respectively. The results indicate that NIR reflectance spectroscopy is an accurate and efficient tool for determining protein content of diverse coarse cereal germplasm for nutrition labeling of nutritional value. On the other hands appropriate condition of cereal material to predict protein using NIR was flour condition of grains.