Plant-based meat alternatives have grown in popularity over the past few years. To investigate the role of starch in meat analogues, a research paper written by scientists from the Netherlands has been published in the journal. Polymers.
Stady: Fibrous structures of starch and gluten. Image credit: badnews86dups / Shutterstock.com
Fake meat growth
Consumer patterns have changed in recent years with more people deciding to switch to a vegetarian or vegan diet for ethical, health and environmental reasons. This trend is expected to continue in the future, and manufacturers in the food industry have developed a growing range of fake meat products that can meet the nutritional and dietary requirements of consumers.
The number of products available on the market is increasing every year. They provide critical nutritional needs such as protein for individuals who have decided not to include meat in their diet. Most importantly, these products must not only provide an alternative to animal products, but also mimic the properties, taste, and texture of meat.
Images of total structures after cutting MS, HVII, PMS, or AS in combination with gluten in HTSC. The numbers in the left column indicate the amount of starch added (dB). The amount of AS added was 10-fold smaller, ranging from 1-8%. All samples contained 40% dry matter (wb). The width of each sample was approximately 5 cm. Image credit: Bühler, JM / Shutterstock.com
Meat fiber simulation
The meat of animals consumed all over the world consists mainly of muscles that have a complex fibrous structure. Accurately simulating these fibers is a technically challenging process in the fake meat industry.
The fibers in plant meat analogues can be produced through various processes. These processes usually combine heat and shearing and can be produced using an extruder and high temperature shear cells. Protein-rich plant products are combined with water, and the basic mechanisms of fiber formation are not currently fully understood.
The current consensus on how to create fibrous structures is that it is necessary to synthesize a multi-phase mixture with specific properties. These properties have undergone extensive research in recent years, along with the role of certain components such as proteins and carbohydrates.
Understand the effect of starch
The use of materials derived from various plants to produce fibers for meat analogues is one of the main research focus areas in the counterfeit meat industry today. Traditionally, fractionation/separation processes are used to purify protein-rich crops, which presents sustainability challenges due to their extensive use of water and energy resources.
Therefore, the development of processes that use functional fractions could provide a path toward improving sustainability, which goes against the stated environmental benefits of reducing animal products in the human diet.
Research has focused on the use of starchy food items, especially legumes in meat analogues. Understanding the interactions between starch and other components, such as protein, is critical to their effective use in these complex food products.
Studies have investigated the effect of starch on product properties such as chewiness and hardness as well as fibrous physical properties. However, the exact mechanisms governing the effect of starch have not been sufficiently explored in the research.
Fracture stress εf in parallel (red) and perpendicular (blue) directions on the added amount of MS, PMS, AS and HVII (dB). The horizontal dotted lines represent values for cooked chicken meat, and data from Schroders et al. Note that the x-axis for AS has a different range than the others (0–0.1 g−1 Instead of 0-1 gm−1). Image credit: Bühler, JM / Shutterstock.com
The study in Polymers It aims to fill this critical research gap. Specifically, the study explores the role of starch in fiber formation in high-temperature shear cells. To the researcher’s knowledge, the effect of starch in high-temperature shear cells has not been explored in the current literature.
Emphasis was placed on how product properties can be modified by the behavior of starch gelation and opportunities to improve meat analog fibrous structures. Three starch samples with different amylose contents were examined. The properties of these starches (low amylose, intermediate amylose, and high amylose starch) have been extensively classified in the current literature.
The content of amylose and amylopectin largely determines the functional properties of starch. By focusing on starch with different amylose content obtained from one crop (maize,) the influencing factors such as the type of crop in the research were reduced. All samples of different starch content were gelatinized.
Starch samples prepared with a recipe containing bean flour and gluten were evaluated. Beans are low-fat, protein-rich and starch-rich legumes that are used in a variety of cuisines around the world. The beans were gelatinized and used in both their original conditions and pre-treated in a high-temperature shear cell.
By combining all the ingredients, the authors transferred the results of pure starch to less refined ingredients that could be used in the manufacture of meat analogues. The bean was chosen because of the suitability of the isolated protein to form fibrous structures with gluten in high-temperature shear cells. Unrefined bean meal is not sufficient for this process.
Photographs of the overall structure after gluten shearing with untreated MS and FM, as well as pre-gelatinized MS and FM in HTSC. All samples had a dry matter content of 40% (wb), with a gluten content of 50% (dB). Each specimen is approximately 5 cm wide. Image credit: Bühler, JM / Shutterstock.com
The authors showed that large amounts of starch can be added to gluten to form fibrous structures. Moreover, the unique compositional properties can be incorporated into fake meat depending on the amount and type of starch used. Various technological properties such as water absorption and viscosity were produced depending on the different starch contents of amylose and amylopectin.
By pre-gelatinizing the starch, the composition of the fibrous product was improved and the variation of the Young’s modulus increased, resulting in a product similar to chicken meat. The density of the gluten network improves with increasing strength due to the increase in water absorption at room temperature. The research showed that starch could help produce more accurate meat analogs, and in situ modification of starch-rich crops is suitable for producing fake meat with fibrous structures.
Bühler, JM, Van der Goot, AJ & Bruins, ME (2022) Fibrous structures of starch and gluten Polymers 14 (18) 3818 [online] mdpi.com. Available at: https://www.mdpi.com/2073-4360/14/18/3818.