Seeds are of great economic and biological importance if one takes into account that they have a high oil and protein content, and large starch reserves. Nuts from trees are recommended as part of a healthy diet given their protein, phytochemicals, micronutrients, and unsaturated fat content¹⁴. Seeds and nuts can be the raw material for oil production, which is often extracted by cold pressing—this process generates a by-product known as “press-cake”; or it can also be extracted with organic solvents—in this case, the residue is called “meal”²⁶. The global 2018/2019 oilseed production reached 600.47 million metric tons²⁷, hence huge amounts of oil extraction by-products are available. Although press-cakes and meals are often discarded as waste or used as components for feed supplementation, they are good protein, fiber, and bioactive compound sources^26,28. Moreover, because of the increasing demand of protein products, such waste types are a potential alternative source for protein extraction⁵. However, the oil extraction procedure often decreases protein solubility²⁹ and it compromises its use in beverages. Thus, many of the herein-reviewed patents were related to methods applied to increase or preserve the solubility of proteins extracted from cakes and meals. Furthermore, depending on the raw materials, meals and press-cake often possess undesirable amounts of compounds that decrease protein digestibility, such as fibers and antinutritional factors⁵—such a matter is constantly discussed in most patents as well. Moreover, the preferable protein extraction methods were related to the protein precipitation using an alkaline, acid, or salted solution, followed by a specific filtration and drying technique (Table 1).

Based on the results, rapeseed was the most used seed, since it was the preferable raw material in 25 patents (Table 1). Rapeseed ranks second position of the major oilseed cultivated worldwide, it just loses its position to soybean³⁰. Rapeseed and “canola” are the common names given to species Brassica napus L., Brassica rapa L., and Brassica juncea L; however, the name “canola” only refers to rapeseed varieties presenting less than 2% erucic acid and meal accounting for less than 30 μmol/g total glucosinolates. The crude protein in rapeseed meals ranges from 35 to 40%. At least 40 different protein fractions can be found in this total, but cruciferin, napin, and oleosin are the most investigated ones⁵. Cruciferin and napin are the main storage proteins, they account for 60 and 20% of the protein content in rapeseeds, respectively²⁶. Oleosin presents structural proteins associated with oil components³¹. Although rapeseed has lower sulfur-amino acid levels⁵, canola meal has better amino acid profile than soybean. Nevertheless, canola proteins present many antinutritional factors, as among them glucosinolates, phenolics, phytates, as well as a large amount of fibers capable of compromising digestibility, color, taste, and physicochemical properties²⁹. This finding explains some authors’ interest in patenting inventions that can solve these problem. Patents WO2019110556 (A1) and EP3481220 (A1) explain how to isolate inherently sweet rapeseed proteins presenting low content of antinutritional factors and high solubility, which can be used to reduce the amount of sucrose in beverages, and simultaneously increase protein content in the product. Likewise, BRPI0917295 (A2) provides rapeseed protein isolate that is soluble and stable not only in acid pH but also at higher temperatures. At the moment, Burcon^® is the only manufacturer of high-purity canola protein in the world^32,33, despite the potential of this raw material.

Hemp (Cannabis sativa L.) was the preferable raw material in 11 patents (Table 1). It is mainly cultivated for the industrial use of its seeds, fibers, oil, and meal³⁴. At the moment, hemp is at the mainstream, since it is a sustainable crop that does not require fertilizers, herbicides, and pesticides³⁵. Hemp can be legally cultivated for industrial purposes in most countries worldwide, when it has up to 0.3% of its main psychoactive compound: delta-9-tetrahydrocannabinol (THC)²⁶. Hemp seeds are rich in phytosterols (ω-3 and ω-6) and have ~25% of proteins in its dry weight³⁵. Approximately 65% of the total hemp protein comprises a single globular storage protein: edestin; on the other hand, the albumin fraction consists of 25% of storage proteins²⁶. Although it has low lysine content¹⁵, hempseed protein contains all the essential amino acids and accounts for low amount of antinutritional factors, such as trypsin inhibitor; therefore, it presents high-degree digestibility³⁵. Hempseed protein can be appropriate for athletes and infants, for example, given their quality. Patent BR112015001964 (A2) provides a hempseed protein that is completely soluble in acid beverages (lower than 4.4 pH), without the need of stabilizers or additives. Thus, it can be used for protein fortification in soft and sports drinks, as well as in other aqueous systems. Similarly, CN110150391 (A) disclosed a canned beverage for athletes made with hempseed albumins, which is even better absorbed by the organism than the whole hempseed protein. US2015079235 (A1) proposed hempseed protein using as the main ingredient in an alternative infant formula, which can be either powdered or liquid. Currently, Axiom Foods^® and Good Hemp^®, which offer products with 58 and 85% purity, respectively, are among the hempseed protein suppliers in the world^36,37. Also, Manitoba Harvest^® and LeanHemp^® are brands focusing on the hempseed protein supplement segment^38,39.

Ten patents used Sunflower (Helianthus annuus L) as preferable raw material (Table 1). This species is one of the most cultivated oilseed crops⁴⁰; its seed meal can reach 40% protein content when it is mechanically extracted, and 50% protein content when the oil is extracted with organic solvents⁵. Approximately 85% of the total protein content in sunflower seeds is found in the form of storage proteins (11S helianthinin globulin and 2S albumins)²⁶. Globulin content varies from 40 to 90%, whereas albumin rate ranges from 10 to 30% of the total protein found in seeds. It is possible observing differences in the ratio of these protein fractions since three different sunflower seed types are majorly cultivated—they are used for oil production, human and pet consumption, and ornamentation⁵. Despite its low lysine content, sunflower meal remains a good protein source, given its high digestibility and smaller number of antinutritional compounds⁴¹. Although sunflower seed proteins have low functionality, such a feature is closely linked to denaturation caused by heating at oil extraction, rather than to native proteins themselves. Moreover, phenolic compounds found in sunflower seeds, such as chlorogenic acid, can crosslink with proteins and change its color, functionality, and bioavailability. However, chlorogenic acid is also beneficial for human health⁴⁰ and can be desirable when it is properly extracted from sunflower seed meal. Patent CN109354574 (A) improved a method by using supercritical carbon dioxide extraction to prepare chlorogenic acid and protein powder from sunflower seeds, in separate. This powder is an interesting raw material for making artificial milk and beverages due to its soft flavor. Similarly, FI128029 (B) addresses a sunflower seed protein with enhanced solubility and low phytate content. Its powder is a suitable ingredient for dairy alternatives. Following functionality improvements, BR112018070543 (A2) used enzymatic treatment, heating, fermentation, and pressure treatment to increase the techno-functional and organoleptic properties of sunflower seed protein, which is useful as a beverages’ supplement. Presently, Biotechnologies^® is the only world sunflower seed protein producer whose product has more than 80% purity⁴²; However, it is possible finding other suppliers whose products reach about 50% protein content, among them one finds Austrade Inc^® and ETChem^[®43,44.

Based on the results, cottonseed was the preferable raw material in seven patents (Table 1). Fiber is the most common product made out of cotton; however, cottonseed has great potential as protein source, for both animal and human consumption⁴⁵. Cottonseed meal has ~30 to 50% total protein⁴⁶. Arginine has the highest content (22–34%) of essential amino acids, whereas cysteine accounts for the lowest one (1–2%)⁴⁷. Cottonseed meal is a good protein source for ruminants, but it is not appropriate without treatment for monogastric animals, including humans, who do not tolerate high fiber contents and antinutritive compounds, such as gossypol, phytin, and cyclopropane fatty acids⁴⁶. In total, 80% of defatted cottonseed is used as substrate for edible mushroom crops or as fertilizer, but only 5 to 10% of it is used for animal feeding purposes, a fact that causes huge protein waste⁴⁸. The appropriate extraction of these proteins from the meal is a feasible option to solve this problem. Patents HUE033952 (T2) and PL2498620 (T3) disclosed enhanced methods to produce high-quality protein concentrates and isolates from oilseed meals, including cottonseed, which has incredibly low fiber content and antinutritional factors. These concentrates and isolates are useful as powdered milk analog or to increase protein content of juices, soft drinks, sports drinks, and beverages in general. RU2018129466 (A) disclosed a method to extract cottonseed proteins that can fortify beverages as well. When it is compared to other patents, it also has the advantage of not presenting beany or grassy flavor notes. Nevertheless, so far, cottonseed protein suppliers in the market only provide to animal feeding, they still do not focus on human nutrition.