Rye (Secale cereale L.) is a cross-pollinating small grain cereal crop. It is one of the best sources of protein, starch, carbohydrates, vitamins(i.e. tocopherols/vitamin E), minerals, and fibers (arabinoxylan, β-glucan, cellulose, lignin, and fractan) and bioactive substances, and it is the second most important small grain crop for raw material for bread and bakery goods next to bread wheat. Rye seeds contain 6.3–14.5% protein, mainly accumulated in the rye kernel, but its composition depends on the growing conditions and genetic background.Rye endosperm comprises of storage protein (prolamins) as gluten, and this gluten is composed of a complex mixture of secalinproteins with different sizes and structures, including ω-secalins, high molecular weight-secalins, γ-75 k-secalins, and γ-40 k-secalins. In addition to nutritional values, rye has significant health benefits through lowing cholesterol levels, reducing obesity risk, diabetes, and cancer, enhancing intestinal health, lowering blood lipids, preventing heart diseases and blood sugar regulators, and preventing acne formation, dermatitis, eczema, psoriasis, and other skin disorders. Besides its human health and nutritional benefits, it contains anti-nutritional factors such as phytate, trypsin inhibitors, and polyphenols. From the anti-dietary factors, phytic acid is the most common and affects the bioavailability of zinc, calcium, and iron, making them inaccessible for human use. Therefore, to solve the existing antinutritional factors, common methods, such as baking, milling, roasting, germination, irradiation, bioprocessing, and extrusion cooking, increase rye’s nutritional value. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis, size-exclusion high-performance liquid chromatography, and reverse-phase high-performance liquid chromatography are the most common methods that detect quality and quantity of rye proteins.