The major market for pea protein application is as a replacement of soy protein, due to concern for GMO soybean, or for vegetarian products in which market animal-base protein such as whey or casein are getting replaced with pulse protein. In addition, need for consuming meat alternatives come from religious and economic reasons, especially in the South Asia, Middle East and African countries. A drastic global population increase will further require the food industry to develop nutritious protein source that can replace scarce animal protein supply in underdeveloped countries.
Two types of meat products utilizing pulses are meat enhancers and meat analogues (replacer). Meat enhancers utilize protein or flour for gelation, emulsification and water-binding functionalities. Examples of these processed meat are salted meat, luncheon meat, boneless ham, sausage, and bologna. Meat analogues have appearance and texture resembling meat. The basic function of pulses in meat analogue is to form a complex, three-dimensional gel network in which fine particles of emulsified meat is trapped, using the starch and non-meat protein as a filler (Farooq and Boye, 2011). Increased cooking yield for retaining water and fat reduces purge loss during cooking yet the effect varies depending on different pulse flours.
Meat replacers or meat analogue use protein for creating texture resembles meat. Texturized vegetable protein (TVP) processed with extrusion technology is commonly used for production of meat replacers and analogues. Types of meat analogues vary on its processing and texture. Dry products such as structured meat analogues and fibrous protein products resembles to whole-muscle meat and relatively high density (Strahm, 2006). High moisture meat analogues are sold refrigerated or frozen and contain high moisture. TVP usually employs mechanical processing with an extruder to obtain meat like chewy and stringy texture when hydrated. Either flour, protein concentrate, isolate or a blend can be used as a raw material. Extrusion process for TVP can denature protein, inactivate anti-nutrient and provide better flavor (Asgar et al. 2010).
While soybean has been a major ingredient for meat analogues and TVP commercially available in the market, pea protein presents a high potential partially due to its similar functionality with soy protein. For example, gel forming capacity, solubility, and emulsifying capacity of pea protein and soy protein are relatively similar compared to the other types of legumes while pea protein exhibits better oil and water absorption capacity than soybean (Asgar et al. 2010).
Two popular types of meat analogue are produced with low moisture extrusion (<35% moisture) and high moisture extrusion (>50% moisture) (Osen et al. 2014). Low moisture extrusion has been used for many years with the product made with soy ingredients; yet the sponge-like texture and appearance of products from low moisture extrusion processing varies significantly from meat, thus increased attention to using high moisture extrusion cooking exists. Although there is little research published on the processing method, extrusion processing parameters such as motor torque, die pressure and specific mechanical energy (SEM) are critical. Texturization occurs in a cooling die; thus, a relatively long cooling die is used for this process. Temperature has to be lower than 100 OC before exiting the extruder to avoid the expansion, resulting in a high density product (Strahm, 2006).
Osen et al. (2014) showed that SEM controls macromolecular transformation as a result of protein-water interaction followed by cooking die which solidifies the structure to meal like texture. Additionally, functional and chemical properties of raw ingredients such as water binding capacity, emulsion capacity and viscosity profile had significant influence on texture properties of final products. The authors concluded that the effects of functional properties of raw materials apparently have less impact on texture development compared to the processing parameters; yet, further studies were recommended to confirm the findings.
Egg replacement has been drawing the attention of the food industry for similar reasons as meat replacers. In addition, egg is one of 8 allergens affecting up to 4% of population in the U.S., as reported by the Center for Disease Control. There are a few egg substitute products available in the market. Powdered egg replacers are used in the baked goods. Egg-free mayonnaise products have been introduced to the market as a vegan product. These products use ingredients that provide the similar functionality as eggs, which include water and oil absorption, solubility, foaming, emulsion, coagulation, and leavening to provide ideal texture, density, mouthfeel and elasticity to the product (Soderberg, 2013). The main egg components providing these functionalities are protein and fat. Pulse protein also provides these functionalities. In addition, it is a common practice that additional ingredients including modified starch and hydrocolloids are used to supplement some functionalities.
Pea protein concentrate and isolate have been sued as egg replacers in cakes. Laboratory prepared protein isolate had slightly different functionalities. However, the results showed little difference between control and pea protein treatments in terms of baking quality such as diameter, shrinkage values and weights. Sensory evaluation revealed better moisture retention of the cake made with pea proteins compared to the control. The most noticeable difference between pea protein isolate and concentrate was the flavor profile. Pea protein isolate had a neutral, less beany flavor compared to pea protein concentrate. When used in the chocolate cupcake formula (See Appendix C for the formula), beany flavor from pea protein concentrate was barely noticeable as chocolate flavor complementing the beany flavor.
For more information, refer the technical information brochure prepared by the Northern Pulse Growers Association: