Let’s focus on milk and soy. To say which of these two protein sources is more significant would be to detract from their uniqueness. Milk, after all, is animal based, and soy is vegetable. Milk protein accelerates physical recovery from numerous ailments, and soy protein mitigates heart disease.
Let’s focus on milk and soy. To say which of these two protein sources is more significant would be to detract from their uniqueness. Milk, after all, is animal based, and soy is vegetable. Milk protein accelerates physical recovery from numerous ailments, and soy protein mitigates heart disease. The list of differences could be endless but the point is made: both provide protein, but it’s how they deliver it, and what additional functional properties they provide, that pushes researchers to dig deeper into their mysteries.
And it’s not just nutrition or scientific curiosity that is sparking the research. In a 2006 report, business consulting firm Frost & Sullivan (San Antonio, TX) predicted that by 2010, the protein ingredients market would grow to $3.95 billion in sales at a rate of 5.64% per year, up from $2.69 billion in 2004.
“Consumers are becoming educated about the benefits of protein in the diet,” says Jean Heggie, North American marketing director for the Solae Co. (St. Louis). “They are particularly interested in protein-containing foods for their benefits in providing satiety, sustained energy, and the ability to support lean muscle mass development.”
THE PHYSIOLOGY OF MILK PROTEIN
It has been known for some time that milk, and its constituent proteins casein and whey, may help weight loss, improve immune function, control appetite, aid relaxation, and improve memory. Research conducted in the past year has either corroborated or extended these findings, especially in the case of whey proteins promoting lean body mass and the milk proteins Human Alpha-lactalbumin Made Lethal to Tumor Cells (HAMLET) and Milk Fat Globule Membrane (MFGM).
In April, researchers from the U.S. Department of Agriculture (USDA; Washington, DC) presented a new clinical trial abstract at the Experimental Biology meeting in San Francisco. This abstract concluded that individuals supplementing their diet for six months with whey protein weighed less and had less body fat compared with individuals who consumed a carbohydrate supplement. The study’s goal was to compare both soy protein and carbohydrate with whey protein to examine the effects of whey on both body weight and composition.
Perhaps more exciting has been the research conducted on milk protein regarding human immune functions. A 2004 paper published in Cellular and Molecular Life Sciences reported that the milk component HAMLET appears lethal to tumors. This study tested the effect of HAMLET on mammary cells. Plastic pellets containing HAMLET were implanted into the fourth inguinal mammary gland of lactating mice for three days. Exposure of mammary tissue to HAMLET resulted in morphological changes typical for apoptosis, or programmed cell death. The results suggest that HAMLET can mediate apoptotic cell death in mammary gland tissue. Similarly, a 2005 report published in The Journal of Dairy Science found that MFGM proteins that reside in the surface of milk-producing cells react in human digestion to inhibit cancer cell growth, act as a vitamin binder, and potentially suppress a number of health conditions.
“MFGM is a perfect example of a combination of a food protein with a lipid to form a component that fights cancerous cells,” says Rafael JimÃ©nez-Flores, PhD, professor of dairy science at California State Polytechnic, San Luis Obispo (Cal Poly SLO).
“We are finding that the function of some of the milk proteins is not fully developed until we start to digest these proteins in the gut, where we also have some fat mixed in, and under acidic conditions that allow the components to get together and fight cancerous cells,” JimÃ©nez-Flores says. More specifically, he thinks the components may fight cells with an altered apoptotic mechanism that in elder humans can result in cancer. “We do not know what these cells would be doing or are doing in the neonate,” he says, “but the imagination is boggled.”Additionally, a study published in the June 2005 issue of The Journal of Nutrition discovered that supplemental dietary whey protein concentrate reduces rotavirus-induced disease symptoms in suckling mice. A different 2005 study published in Nutrition Research found that modified milk powder supplemented with immunostimulating whey protein concentrate (IMUCARE) enhances immune function in mice.
RECENT SOY PROTEIN RESEARCH
As with milk protein, a great deal of the recent research conducted on soy has built on past findings. For soy, these past findings deal predominantly with the reduction of menopausal symptoms and attenuating bone loss in women; a reduction in the risk of breast, prostate, and colon cancer; and improvements in cognitive performance. For example, soy has often been shown to promote satiety, which can lead to weight loss. Animal research presented in the May 2004 issue of The Journal of Nutrition indicates that soy protein, compared with other proteins, can also affect fat metabolism in the liver and adipose tissue. Extended discoveries regarding soy and cholesterol have also been achieved.
“Soy protein has been researched for its cholesterol-lowering benefits for more than 30 years,” says Greg Paul, PhD, director of health and nutrition at Solae. “Consistently, researchers have reported reductions in cholesterol of between 3 and 10%. Findings published in a 2006 American Heart Association Science Advisory report indicate that an individual’s cholesterol level before adding soy protein to the diet has little influence on the cholesterol-lowering benefits. This means that even those with ‘normal’ cholesterol levels can benefit from consuming soy protein. As an example, a study published in a 2006 American Journal of Clinical Nutrition study showed that healthy young men with cholesterol levels of about 180 mg per deciliter were able to significantly improve their blood lipid profile and thus reduce their risk for heart disease by consuming 30 g of soy protein daily for two months.”
Paul notes that exactly how soy protein works to lower cholesterol is speculative at this point. Some evidence indicates that specific peptides or protein fragments interfere with cholesterol absorption in the intestinal tract, while other data suggest that specific peptides may affect the way the liver removes cholesterol circulating in the blood. Companies like Solae are investing heavily to understand how soy protein functions in the body to lower cholesterol, as it may be possible to reduce the amount of soy protein needed to see a cholesterol-lowering benefit. According to Paul, right now an amount of 25 g per day is necessary, and higher levels do not seem to augment the effect. Reducing the amount needed to lower cholesterol would open more opportunities to formulate a wider variety of great-tasting, heart-healthy foods containing soy protein.
VIABILITY IN FOOD FORMULATION
While the effect of a protein ingredient on the human body is one side of the protein equation, there is also the equally important consideration of whether or not a protein source is workable in a final product. Solubility, taste, and texture matter, and researchers are eager to discover innovations in this area.
Cal Poly SLO has a dairy ingredients applications program funded by Dairy Management Inc. (Rosemont, IL). This program is designed to help product formulators find new and better ways to utilize protein ingredients like nonfat dry milk, milk protein concentrates, and whey protein concentrates. One example of their progress is a recent examination of how protein can be utilized effectively to develop high-protein bakery products, energy bars, and nutritional beverages.
On the soy side, in October 2005, Solae teamed up with global agricultural products company Monsanto (St. Louis) to develop and market a new line of conventionally bred soy proteins. These proteins have improved flavor and solubility as well as higher levels of beta-conglycinin, a satiety-providing compound produced by the digestion of protein. In addition, Solae has offered up innovative solutions in protein powders and textured soy protein ingredients that allow for greater food formulation options.
“Our proteins designed for bars are specifically designed to help manufacturers manage texture, extend shelf life, and prevent bar hardening,” says Heggie. “Technology introduced in 2004 demonstrates a fivefold improvement in the rate of bar hardening versus previous technologies. These products can be blended at various ratios to target a specific texture that a manufacturer is looking for, from very chewy to more cookielike.”
ECONOMICS OF PROTEIN
Of course, a major consideration for both protein ingredient producers and food formulators is whether or not a protein ingredient is economically viable to produce and sell. Part of this consideration is relative to the challenges of keeping manufacturing costs low, but the other part is relative to public acceptance of protein as both a nutrient and as a functional food. As far as public acceptance of protein ingredients goes, it is clearly accelerating; one has only to source FDA’s health claim regarding soy and its relationship to heart disease to prove that point. But other indicators of public acceptance and awareness are also bellwether. Dietary Guidelines for Americans 2005, published jointly by the U.S. Department of Health and Human Services (Washington, DC) and USDA, emphasizes the benefits of “lean” proteins like soy.
“Recently, the costs of many common dairy proteins have been high and quite volatile,” says Heggie. “Due to these economic realities surrounding dairy proteins, there has been a tremendous amount of interest in how soy protein can be used to offset these effects. In our sensory science area, we have conducted a great deal of research looking at the benefits and differences of soy versus dairy proteins in various applications. Sensory research by Solae in both ready-to-drink high-protein neutral beverages, as well as high-protein dry blended beverages, confirmed that beverages made from blends of dairy and soy proteins score higher in ‘overall liking’ with consumers than similarly formulated high-protein beverages made with either all soy or all dairy proteins. Such formulas generally result in protein cost savings in the range of 15 to 50%, depending on replacement levels, versus all dairy–based formulas.”
But advances in milk proteins, both in nutritional value and economic development, will undoubtedly keep pace with soy. According to JimÃ©nez-Flores, MFGM proteins have all the characteristics of large commercial and nutritional potential. They are now a recognized good fraction of protein, but are part of waste streams of processing dairy foods. Scientifically, they represent a challenge and are, for the most part, “terra incognita” for protein explorers. But while these proteins are very diverse, technology has advanced to a point that we can dream ways of recovering them economically.
Study Shows Dairy Peptides Enhance Athletic Performance
Sports beverages that contain dairy peptides seem to help athletes perform better than sports beverages that contain only carbohydrates, according to the results of a new study conducted at the German Olympic Support Center (Rhein Ruhr, Essen, Germany).
In the study, 50 athletes between the ages of 17 and 39 drank one of two beverages: Multipower Re-Charge, a sports drink that contains a combination of carbohydrates and PeptoPro peptides from DSM Food Specialties (Delft, The Netherlands), or a regular sports drink. All the athletes abstained from exercise 24 hours before starting the study, fasted overnight, and then exercised. After a four-hour recovery phase, the athletes drank four 330-ml doses of Re-Charge or the carbohydrate-based drink. Following the recovery period, the athletes exercised again, and the entire test was repeated after one week. According to the researchers, the athletes who drank Multipower Re-Charge saw a significant improvement.
“The trials showed an improvement of 2% of maximal physical performance after a four-hour recovery period in which PeptoPro was consumed,” says Stefan Siebrecht, DSM’s business development director for PeptoPro. “This really matters for athletes who need to recover rapidly between races and during training.”
Siebrecht adds that the small size of PeptoPro’s milk proteins, which are composed of chains of dipeptides and tripeptides, enable athletes to fully and rapidly absorb the ingredient without adding stress to the digestive system. Muscle tissue, therefore, can access the nutrients more quickly than other protein sources.
“The degree of ergonicity of PeptoPro in this study is as high as caffeine, which increases the performance of trained athletes by 1–3%,” Siebrecht says. “Caffeine is regarded as a potent substance to boost the performance of athletes, but compared with caffeine, PeptoPro offers more nutritional benefit and is safer, as it has no negative side effects.”
“Today, the proteins of the MFGM are in the same place as the whey proteins were 10 years ago, full of promise and needing discovery,” says JimÃ©nez-Flores. “Whey proteins represent many millions of dollars in the food industry, and I am sure that MFGM proteins will, too, in some years.”
SIGNIFICANT UNREALIZED DEVELOPMENTS IN PROTEIN
For milk protein, the frontier may be similar to that which is currently going on with MFGM research-i.e., the examination of how certain proteins interact with other nutrients (such as fat) and the digestive process to provide functional benefits. For soy, the frontier may be a further discussion of how protein interacts with cholesterol.
“There are still many minor proteins in milk that have functions that we do not know,” says Phillip Tong, PhD, a professor of dairy science at Cal Poly SLO. “Such proteins and their interactions with the other constituents of milk may be important to human health, but we just don’t know enough about them. As we use genomics and proteomics to understand the milk protein system, we will gain new insights into the answers to these questions.”
“I believe one of the most interesting questions yet to be answered regarding soy protein is how it works to lower cholesterol,” says Paul. “We see consistent cholesterol reductions of 3–10% when 25–30 g of soy protein is added to the diet. By understanding the mechanism of action, we may be able to improve the cholesterol-lowering efficacy of soy protein.”
Also, according to Paul, a second question researchers are beginning to ask about soy protein, as well as many other nutrients like milk, centers on genetic differences of individuals consuming soy protein and what physiological effects are observed or not observed. This is an emerging field that promises to add volumes of information on the interaction between nutrition and health in the upcoming years.