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Plant vs. Animal Protein Functionality in Model Systems

Posted on:November 17, 2019

“FUNCTIONAL DIFFERENCES BETWEEN dairy and plant proteins will affect performance in beverage and bar applications,” said Hong Jiang, Wisconsin Center for Dairy Research, in her presentation titled “Characterization of Functional and Sensory Properties of Commercial Food Protein Ingredients.” Jiang and fellow researchers recently characterized the functional and sensory properties of 30 different, commercially available dairy and plant protein ingredients.

Dairy proteins that were tested included milk and whey proteins. Plant proteins included potato, pea, soy and rice protein. All ingredients were >75% protein and were hydrated for one hour at room temperature before testing. Functionality tests were performed at the protein’s native pH. Below are key results. Water-holding capacity is the ability of the protein to trap water within a protein’s three-dimensional structure. This property is important for processed meat, soups and sauces, and bakery/pastry. The proteins with the best water-holding capacity were milk, soy and pea.

Viscosity is also a measure of water-holding capacity and demonstrates the flow properties and thickening ability of a protein ingredient. Of the proteins tested, milk and pea protein had the highest viscosity at 10% protein solution.

Heat stability is an important property for beverages. At pH 3, whey proteins had the best heat stability, followed by plant proteins, then milk proteins. Whey protein isolate (WPI) is ideal for clear RTD applications, such as juice, isotonic drinks and protein water. However, not all whey protein ingredients will be clear. Whey protein concentrate (WPC) ingredients contain fat, so they will make beverages cloudy or milky-looking. WPI is the product suitable for clear drinks. Heat stability at pH 7 is important for UHT beverages and other low-acid foods. At neutral pH, the most stable proteins were milk and whey.

Stability in pH 7 beverage: Ten of the proteins were also test- ed for stability in UHT beverages based on their heat stability results at pH 7. Formulas were standardized to 5% protein; the pH was adjusted to 7; and formulas were processed in a UHT MicroThermics unit at 140°C for three seconds. At day one, all beverages were stable; however, the rice protein had a sandy texture. The color of the beverages varied by protein source. Bitterness increased after heating. Some of the protein beverages became slightly thicker over two weeks’ storage.

Stability in pH 3 beverage: Seven of the proteins were also tested in a high-acid beverage application based on their heat stability results at pH 3. The native whey, WPI and potato protein produced clear beverages. All beverages exhibited some astringency, but the whey protein beverages had a cleaner and more acceptable flavor profile. Three of the four plant beverages separated during storage.

Emulsion activity is important for salad dressing and coffee creamer. Whey, milk, pea and soy protein were better at forming an emulsion than potato and rice protein. Emulsion stability was measured after heating to 80°C for 30 minutes. Milk, soy and pea proteins exhibited good emulsion stability.

Foaming ability is important for mousse, cake and whipped topping. Whey proteins had excellent foaming ability. Whey proteins also had good foam stability as measured after sitting for 30 minutes.

Gelation ability and gel strength are very import- ant for cake, pie filling and processed meat. Heat is required to induce gelation of protein ingredients. Only 12 of the 30 ingredients tested were able to form a gel. All whey ingredients formed a gel.

Sensory properties in 10% hydrated solutions were determined by a trained panel of nine individuals using an established sensory language. Plant proteins had higher intensity of astringent, bitter, sour and beany flavor than dairy proteins. (Research done by Dr. MaryAnne Drake at North Carolina State University.)

Model protein bar. All 30 protein samples were tested in a typical bar formula. The ratio of carbohydrate/protein/fat was 40/30/30. The bars were stored at room temp or in a 45°C incubator for 90 days. Following room temperature storage, all protein bars were darker in color.

On day one, all protein bars appeared soft. After three months of storage, the milk and plant protein bars became significantly harder than the whey protein bars. After 90 days of storage at elevated temperatures, almost all bars reached an unacceptable level of hardness. Some of the whey protein bars remained comparatively softer. Rice protein bars retained softness during storage but tasted grainy and sandy.

All proteins are unique. Dairy proteins offer a comprehensive solution to end-users compared to plant proteins. When selecting a protein ingredient, remember to choose a suitable functional test for the desired end-use application and manufacturing process.

“Characterization of Functional and Sensory Properties of Commercial Food Protein Ingredients,” Hong Jiang, MSc, Research Specialist, Center for Dairy Research, University of Wisconsin-Madison

This presentation was given at the 2019 Protein Trends & Technologies Seminar. To download free presentations and the Post-conference summary of this event, go to https://www.globalfoodforums.com/store/protein-seminars/

See past and future Protein Trends & Technologies Seminars at https://www.globalfoodforums.com/store/protein-seminars/


Research into Improving Plant Protein Ingredients

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PLANT PROTEINS have come to the fore for a number of reasons. For one, [the raw materials generally] cost less than animal proteins. But they also align well with a number of emergent consumer trends, such as vegetarianism, veganism and sustainability. Thus far, however, proteins’ functionality as ingredients has lagged behind that of animal proteins.

Prof. B. Pam Ismail, Associate Professor, Dept. of Food Science and Nutrition, and Director of University of Minnesota’s Plant Protein Innovation Center, discussed some intriguing technologies that should expand the use of plant proteins in foods and beverages. She also provided details on two new, interesting protein-rich oilseeds under evaluation for potential commercialization.

“When investigating new and novel proteins, we need to know how to obtain desired protein ingredient functionalities through cost-effective extraction and processing techniques,” said Ismail. In addition, she said, “If they don’t taste good, consumers won’t eat them.” Cost-effectiveness, functionality and taste must go hand-in-hand.

The search for new plant protein sources to meet rising global demand led Ismail’s researchers to focus on alternate sources to soy, such as peas. She noted that, in 2012, 81% of commercial (plant) protein ingredients were obtained from soy. By 2017, soy protein’s market share had dropped to 61.4%, while pea protein’s share rose from 7.6 to 21.2% and continues to rise. Yet, pea protein processing technology remains in a relatively early stage, said Ismail.

One big quality variable is solubility. Most plant proteins (globulins) exist deeply imbedded within fiber and starch matrices, with water- loving (hydrophilic) amino acids on the surface and water-repelling (hydrophobic) amino acids within the interiors of the protein molecules. The hydrophilic amino acids on the surface are what render proteins soluble. During processing, however, conditions such as temperature, shear or changes in acidity can cause proteins to unfold (i.e., denature) and expose the interior hydrophobic amino acids, causing the proteins to aggregate and precipitate. Therefore, the objective of plant protein extraction and purification is to minimize the denaturation conditions that compromise protein integrity and function. Ismail outlined some of the new technologies being developed at her research center.

The first step is to optimize extraction conditions, said Ismail. She cited three techniques: isoelectric precipitation, salt extraction and ultrafiltration. In addition, Ismail’s researchers are investigating new techniques whereby to modify the surface characteristics of extracted proteins in order to enhance stability, such as targeted enzymatic modification (the selective hydrolysis of protein sub-units); glycation (conjugation of a reducing carbohydrate with a protein to increase stability); and cold plasma (the application of partially ionized air to oxidize protein surfaces).

Comparing extraction techniques, Ismail averred, “We found that salt and ultrafiltration yielded proteins that were less denatured and more thermally stable than proteins extracted through pH modification.”

As Ismail explained: “When considering current commercially available protein choices for beverage applications, whey remains the dominant protein isolate, with close to 100% solubility. Soy protein isolate isn’t that great, with slightly less than 20% solubility, but it is still better than pea protein isolate, which exhibits 5-6% solubility. Using salt-based extraction, we were able to increase pea protein solubility six-fold. When combined with targeted enzyme hydrolysis, we approached 90% solubility; with glycation, we achieved 100% solubility.” (Similar to whey protein, that is.)

Ismail’s group has been applying these protein molecule and process- modification techniques to two promising oil seeds, camelina and pennycress, with encouraging results. “These are winter crops favored for short growing seasons, and both are rich in fat (30-40%) and protein (25-30%),” she said. Modified camelina protein, in particular, shows promise of exhibiting stability in highly acidic beverages, although she admitted some flavor issues remain to be resolved, especially in pennycress protein.

In response to a question from the audience, Ismail added that, while the focus of her team’s research has been on increasing protein solubility, the same techniques could also apply to increasing protein hydrophobicity (insolubility), leading to gluten-free protein alternatives for baking, for example.

In a global market where protein demand is likely to remain, in Ismail’s words, “steep and long-term,” the development and commercialization of new protein sources and modification technologies can only expand product developers’ fields of dreams.

“Plant Proteins: Structural and Functional Properties & Use in Food and Beverage Formulations,” Prof. B. Pam Ismail, Ph.D., Associate Professor Dept. of Food Science and Nutrition, and Director of University of Minnesota’s Plant Protein Innovation Center

This presentation was given at the 2019 Protein Trends & Technologies Seminar. To download free presentations and the Post-conference summary of this event, go to https://www.globalfoodforums.com/store/protein-seminars/

See past and future Protein Trends & Technologies Seminars at https://www.globalfoodforums.com/store/protein-seminars/


Specialty Diets for Athletes to Elderly Needs

Posted on:November 15, 2019

MARIE SPANO, MSC, RD, CSCS, CSSD, leading Sports Nutrition Expert began her talk, “Sports Nutrition and Specialty Diets: From Keto to Vegan,” by emphasizing that protein isn’t only for bodybuilders. It also has a powerful role in weight management; functional living as we age; and disease prevention. Spano is the Sports Dietitian for the Atlanta Braves, Atlanta Hawks and Atlanta Falcons, so she has varied experience with nutrition issues, from top athletes to the general population.

Research shows low protein intake is associated with a reduction in muscle mass and strength throughout the lifecycle. Cortical bone increases up until age 25-30. Women and men lose 35 and 23% of cortical bone with aging, respectively. Protein makes up about 50% of bone volume and 33% of bone mass. Elderly persons who have osteoporotic hip fractures are often undernourished.

In senior hip fracture patients, protein supplementation (20g) resulted in fewer deaths, shorter hospital stays and attenuation of proximal femur bone loss (Schurch et al. 1998. Ann Intern Med. http://bit.ly/2RHSY3z).

Protein is also beneficial for weight management. Protein improves satiety; helps retain muscle mass when dieting; and more calories are burned when digesting protein. Spano described the thermic effect of food (TEF), noting that 1lb of fat burns 2 calories/day at rest, whereas 1lb of muscle burns 6 calories. Further, she said, “TEF of protein and carbs is not significantly different between lean and obese people, but the TEF of fat is significantly lower in obese subjects, suggesting a reduced thermogenic response to fat”.

Muscle protein synthesis rates are lowest first thing in the morning. So, after an overnight fast, a higher protein breakfast has the added benefit of up-regulating muscle protein synthesis, advised Marie Spano.

The timing of protein consumption will affect satiety. Under conditions of energy balance, higher protein meals (0.6g of protein/kg/day) made no difference in postprandial or overall fullness. However, during energy restriction, a higher protein breakfast had the greatest effect on meal-related fullness and overall fullness over a 15-hour period (Leidy et al. 2009. Br J Nutr. http://bit.ly/2xlVrak).

Spano went on to emphasize, “Because rates of muscle protein synthesis are lowest first thing in the morning, after an overnight fast, a higher protein breakfast has an added benefit of up-regulating muscle protein synthesis” (Layman DK. 2004. J Am Coll Nutr. http://bit.ly/2XHIuGw).

Healthy athletes don’t need protein powders, as long as they get enough from meals. The peak muscle-building period is likely less than two hours after finishing training for trained individuals (Mori H. 2014. J Physiol Anthropol. http:// bit.ly/2KKgBI9).

“Consistently eating protein soon after body building has a small-to-moderate effect on muscle growth and may have a positive effect on muscle strength, either due to timing or by contributing to greater total protein intake over the day,” she stated.

Moving onto keto diets, Spano explained that, traditionally, these are 80-85% fat and 10-15% protein which, when plant- based, focus on nuts, seeds, avocado and olives. Paleo diets can be high-protein, yet plant-based or vegan, by using nut and seeds. Or they can be keto-friendly when using fish and oils from nuts and fruits.

Spano stressed combining plant proteins to get all EAAs and eating more total protein to make up for low bioavailability, if relying on plant proteins (with the exception of soy, which is a complete protein). “Pulses,” she noted, “are hot. And, in their whole state, they offer fiber, vitamins, minerals and plant compounds; they are non-GMO, gluten-free and clean label.”

Microalgae are a novel source of protein and a diverse group of species that doesn’t require arable land or water to grow. However, “Protein digestibility in the raw, unprocessed state is poor, and they are low in lysine and methionine,” said Spano.

Nutrients from dairy foods are difficult to replace, because they provide “shortfall” nutrients—calcium, potassium and vitamin D. Spano stated, “Almond milk is water plus a few almonds, with added vitamins, and the calcium settles to the bottom of the container.” Other nutrients of concern include magnesium, phosphorus, riboflavin, and vitamins A and B12.

In the development of products for weight loss, Spano suggested that more protein is better but does tend to reduce the moisture, which can result in a dry product. Also, she said, “Add fiber for satiation, not satiety; use natural sweeteners with no added sugar.”

Spano also advised that older consumers should consider easy- to-open, ready-to-eat products that require minimal preparation and that are soft and easy to chew. Consider protein “compliments,” as it is hard for many to eat a high- protein meal.

“Sports Nutrition and Specialty Diets: From Keto to Vegan,” Marie Spano, Sports Nutrition Expert

This presentation was given at the 2019 Protein Trends & Technologies Seminar. To download free presentations and the Post-conference summary of this event, go to https://www.globalfoodforums.com/store/protein-seminars/

See past and future Protein Trends & Technologies Seminars at https://www.globalfoodforums.com/store/protein-seminars/


Effective Use of Colors for Optimal Flavor Perception

Posted on:November 10, 2019

Clean labeling efforts may mean colorants will be avoided, yet color may prove essential in capturing how consumers perceive a food product, noted Debra Zellner, Ph.D., Professor of Psychology at Montclair State University, and Affiliated Faculty Member at Monell Chemical Senses Center. Zellner provided an illuminating discussion of how the color of food (and its packaging) affects consumers’ expectations for odor and flavor in her presentation: “The Effect of Color on Odor Perception: Toward More Efficient Ingredient Use.”

The odor associated with food is perceived orthonasally (when detecting the food’s aroma) or retronasally (when food is in your mouth, i.e., “flavor”).

Food color affects the perceived intensity of orthonasal odor, with colored foods (regardless of color) rated as having more intense odors than clear foods. In contrast, colored foods were perceived retronasally as less intense than clear foods.

Food color also affects flavor identification, which in turn affects how well a consumer likes a food. “Most people are terrible at identifying flavors or odors,” commented Zellner. If the flavor and color of a food are incongruent, subjects will perceive the flavor to be something congruent with color. For example, a clear cola soda might be perceived as lemon/lime rather than cola.

If the flavor and color of these popsicles are incongruent, consumers will identify the flavor to be more congruent with the color. For example, consumers will associate the red popsicle with flavors such as raspberry, strawberry or cherry—even if the red popsicle actually has a blueberry flavor.

How well a color matches the flavor of a food also affects how well the food is liked, with foods less well-liked when their flavor and color are incongruent—unless it is apparent what the flavor is supposed to be. As explained by Zellner, “Green beer is still okay on St. Patrick’s Day,” because you know the beverage tastes like actual beer—not mint or apple.

Zellner detailed some of the psychology underlying these results. When stimuli are paired together repeatedly over time, an association between them develops. For example, if you are a coffee drinker, a brown-colored beverage will elicit the perception of coffee. The odor perception due to the color alone is similar but weaker than that produced by the actual stimulus [i.e., coffee aroma], but color can add to and enhance the actual odor.

One recent study tested how a raspberry/lemon-flavored beverage was perceived when colored yellow, red or left clear. When colored yellow, the soda had more of lemon aroma than did the same beverage when red or clear in color. The effect was limited to the scent, however, because the color did not influence the perceived taste of the beverage

Inspired by New York Times food critic Mimi Sheraton, Zellner’s group also investigated whether packaging color provides a clue to the flavor of the food inside. Unflavored, neutral- colored hard candies were wrapped in various colored papers. When still wrapped, the color of the wrapper influenced what flavor the sub-jects believed the candies were. After unwrapping, however, the wrapper color did not affect the flavor subjects assigned to the candy. Most subjects predicted that unwrapped, neutral-colored candies were mint, vanilla or coconut in flavor. The perceived flavor when tasting the uncolored candy was often vanilla or butterscotch, flavors normally associated with neutral colors.

A similar study in potato chips (which looked alike, despite different flavors) found that packaging colors affected the perceived flavor of the chips, but only if the subject was already familiar with the packaging color scheme used for different flavors.

In summary, food or packaging color can influence odor or taste perception or expectation in a variety of ways. Food color increases orthonasal (sniff) but not retronasal (in the mouth) odor perception; color can intensify one odor component in a complex product with multiple odors; color does not increase flavor intensity, but color will change expectation, identification and enjoyment of a flavor; and food color matters more than the packaging color, especially when food color predicts flavor. However, when all flavors look similar, packaging colors can influence flavor expectations.

“The Effect of Color on Odor Perception: Toward More Efficient Ingredient Use,” Debra Zellner, Ph.D., Professor, Psychology, Montclair State University & Monell Chemical Senses Center

This presentation was given at the 2019 Clean Label Conference. To download free presentations and the Post-conference summary of this event, go to https://www.globalfoodforums.com/store/clean-label-conferences/#2019

See past and future Clean Label Conferences at https://www.globalfoodforums.com/clean-label-conferences/


An Update on Label-Friendly Surfactants and Emulsifiers

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Surfactants and emulsifiers constitute probably the most technically complicated category of food ingredients, declared Peter Wilde, Ph.D., Research Leader, Quadram Institute of Bioscience, University of East Anglia (UK), in his presentation “Challenges & Solutions: An Update on Label-Friendly Surfactants and Emulsifiers.” Wilde laid down a foundational outline of emulsifier and stabilizer chemistry from which he launched an off-road overview of emerging clean-label alternatives.

The magic of emulsions is illustrated in how the mixing of two liquids or a liquid and a gas can transform the mixture into a solid,” he began. The key is high-shear mixing. “When you create very small droplets of oil in water, they behave as hard spheres. If you get enough of them, they form a hard material with a solid appearance.”

The droplets must be stabilized against re-coalescence, how- ever, which is where stabilizers and emulsifiers come in. Gums and thickeners stabilize the water phase. Emulsifiers stabilize the oil-water interface.

Recent consumer demands for clean labels have shifted the industry’s focus toward natural emulsifiers and stabilizers, such as phospholipids. “They are ubiquitous in nature, as every plant and animal cell are stabilized by phospholipids,” said Wilde. Phospholipids, such as lecithin, are naturally present in egg yolks and oil seeds. Some proteins, too, can function as natural emulsifiers and stabilizers.

When searching for foods with clean labels, consumers prefer natural emulsifiers, such as lecithin derived from egg yolks and oil seeds—fearing chemical-sounding ingredient names of which they have no familiarity.

In past decades, the focus was to chemically enhance natural ingredient materials (starches, fats) in order to improve their functionality. For example, natural triglyceride fats were enzyme-treated to create mono- and diglycerides. Unfortunately, this does not comport well with modern clean label expectations, so the focus today is on all-natural, minimally enhanced emulsifiers and stabilizers that are both label-friendly and effective.

“There has been a lot of recent work with saponins, such as quillaja extracts from soapbark,” said Wilde. However, the health effects of saponins are still being debated. Some exhibit anti-carcinogenic qualities at certain levels; some contain anti-nutrients, such as oxalic acid; while others are known to be toxic at high levels,” he explained. As with all bioactive materials, the dose makes the poison.

Also, ingredient label designations trump function, no matter how natural an ingredient may be. Pointing to a commercially available bile salt supplement, Wilde noted that, while he included it in his presentation as a bit of a joke, “(it) really is an excellent emulsifier. It is an approved supplement, so we know that it is safe. However, I do know that it would not be particularly label- friendly.”

Wilde also discussed ongoing research into plant chloroplasts, which contain huge amounts of tightly packed galactolipids. Although they require high levels of processing for extraction, they may also offer the added benefits of promoting satiety and aiding fat digestion.

“Hydrophobins, secreted from filamentous fungi, generated a lot of interest a few years back,” continued Wilde. Highly effective stabilizers, they have been shown experimentally to stabilize ice cream and the foam in beers. He added, however, “They remain difficult to extract and handle.”

Additional and ongoing research investigations include frog- hopper (spittlebug) excretions; tannins; galactomannans from spruce trees; prickly pear cactus extracts; and microbial fermentation extracts.

“Proteins and polymeric emulsifiers may not be as effective as synthetic emulsifiers, but they do provide additional functionality by forming thick layers at interfaces that impart long-term stability,” explained Wilde. Proteins, while not compatible with traditional surfactants, can form elastic films and incredibly strong and stable structures. They can also create unique mouth-feel sensations.

There are process innovations as well. While highly effective, mono- and diglycerides do not project a clean label image. However, they do not have to be listed on the label, if created in situ through the addition of lipase enzymes as processing aids, as is done in bread baking. Added to the dough, the lipase enzymes are destroyed during baking.

New sources of potential emulsifiers and stabilizers continue to be discovered, noted Wilde. “Understanding the structure- function-performance relationships of stabilization and emulsification is key to identifying candidates that, with some minor process modifications, can become viable clean label stabilizers and emulsifiers. Some might even come with added functional and health benefits,” he concluded.

“Challenges & Solutions: An Update on Label-Friendly Surfactants and Emulsifiers,” Peter Wilde, Quadram Institute of Bioscience/University of East Anglia (UK)

This presentation was given at the 2019 Clean Label Conference. To download free presentations and the Post-conference summary of this event, go to https://www.globalfoodforums.com/store/clean-label-conferences/#2019

See past and future Clean Label Conferences at https://www.globalfoodforums.com/clean-label-conferences/


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