Rice malt shows potential to play a bigger role in beer
Malted rice emerges as potential game-changer in beer brewing
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MALTED RICE — SCOTT LAFONTAINE, LEFT, AND BERNARDO P. GUIMARAES EACH RAISE A GLASS OF MALTED RICE BEER FOLLOWING A YEAR-LONG STUDY THAT INVESTIGATED THE SUITABILITY OF RICE FOR MALTING AND BREWING.
view moreCREDIT: UNIVERSITY OF ARKANSAS SYSTEM DIVISION OF AGRICULTURE PHOTO BY PADEN JOHNSON
FAYETTEVILLE, Ark. — Rice is showing potential to play a more prominent role in beer brewing, and it helps that Arkansas produces a lot of it.
Arkansas grows about half of the rice in the United States, mostly long-grain. Meanwhile, climate change and international conflicts are leading to a shortage of the raw materials traditionally used for brewing beer, especially barley.
A new study titled “Investigating the Malting Suitability and Brewing Quality of Different Rice Cultivars,” published in February by the Beverages journal, suggests the potential for malted rice to yield robust fermentations in gluten-free, all-malt beer and also in styles that use high adjunct inclusions. An adjunct is an additional source of sugar for beer fermentation.
Rice and corn have been used as an adjunct grain by American brewers since the 1860s. But the rice has been milled white rice, and not malted. Since the malting qualities of U.S. rice cultivars had not yet been evaluated for brewing qualities, one goal of the study was to identify rice cultivars with high malting potential.
University of Arkansas food science graduate student Bernardo P. Guimaraes was the lead author of the malted rice study, which provides the first publicly available data on 19 rice varieties important to the U.S. rice industry that were malted and analyzed for brewing qualities. Flavor chemist and assistant professor in the food science department Scott Lafontaine served as Guimaraes’ advisor on the research.
“Does rice have what it takes? Scientifically, yes, it is possible,” Lafontaine said.
They have found rice malts with enough enzymatic capacity to fully convert their starch source into fermentable sugar, also known as self-saccharifying malts, that produce a sugary liquid called “wort” in brewing. Lafontaine says the wort from rice malt “seems to yield healthy fermentations with a standard yeast, without adding enzymes or nitrogen supplementation.”
Lafontaine and Guimaraes are both part of the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas and the Arkansas Agricultural Experiment Station. The experiment station is the research arm of the University of Arkansas System Division of Agriculture.
No extra vessel with rice malt?
Malting is the process of germinating a grain through hydration and then drying and heating it to halt germination. The process forms enzymes required to turn the starch into sugar when soaked in hot water for the phase of brewing called “mashing.” Where rice is concerned, brewers have typically used milled white rice, and not rice malt. Using milled white rice calls for an additional brewing vessel because it needs to be boiled to gelatinize the starch so it can be converted into that sugary liquid called wort.
Malted rice, on the other hand, may not require a second vessel. Guimaraes and Lafontaine showed the malted rice to be self-saccharifying with the appropriate mashing conditions. In other words, with the right temperature and time, the starch could be broken down to fermentable sugars that yeast can assimilate and turn into alcohol.
As wheat flour is to bread, malted barley is to beer, with recipes calling for varying levels of a barley as a base malt along with other grains like wheat, rye and oats for different styles of beer. Additional ingredients like roasted barley, and roasted malted barley, develop different flavors and aromas.
In the study, long-grain rice when malted showed the most promise as a competitor to malted barley for sugar content and other brewing qualities. The study looked at short, medium and long-grain varieties of “paddy rice,” or rice with the chaff removed but not the husk. Interestingly, wild varieties of rice that had purple-pigmented brans produced naturally colored gluten-free beers with hues similar to wine.
New findings
Previous public studies on rice malt were performed on Italian and Indian varieties, and the study of U.S. rice malts offered two interesting discoveries, Lafontaine said. For one, the rice varieties had different gelatinization temperatures and mashing parameters seemed to have an impact on the onset of gelatinization.
“While we are not sure exactly what is occurring yet, this is likely due to the unique enzymatic profile of the rice malts and shows that brewers just have to alter their mashing conditions to effectively leverage this material in the brewery,” Lafontaine said of the lower gelatinization temperatures.
The other unexpected finding was that the malted rice showed higher protein levels than previously reported, which offers potential applications as an alternative protein source in foods, Lafontaine said. The new study showed the protein content ranged from 7 to 10.5 percent, and some rice cultivars had protein content comparable to malted barley.
Depending on the variety of rice grown, the study indicates the potential for a value-added product for farmers whose rice turns up with a high level of chalkiness during milling. Chalky rice is opaque and tends to break when being processed, making it less valuable as a food product. However, chalkiness would not have as much of a bearing on quality if sent to a maltster and turned into rice malt. High nighttime temperatures during a rice kernel’s development have been shown to contribute to chalkiness. As the climate warms, this will be a continual issue for farmers and scientists to contend with, Lafontaine noted.
Economics and flavor
Although the chemical analysis of the malted rice is promising, Lafontaine is working with the agricultural economics and agribusiness department to conduct a feasibility study considering many economic factors that compare malted rice and malted barley.
One of the most pressing economic factors is the cost of barley, which has increased in the past four years. The increase has made long-grain rice “cost equivalent” to barley, Lafontaine said. Barley is grown in areas with cooler climates, while rice is grown in warmer climates. So, climate change and global warming are other factors for long-term economic impacts of barley and rice as beer ingredients, he added.
“By offering a more locally sourced grain for Southern and U.S. brewers, despite paddy rice being proportionally more carbon dioxide intensive to grow than malted barley, the lack of international shipping may potentially make up the difference in carbon dioxide,” the study notes. “Additionally, rice is a gluten-free source of starch for brewers and beverage/food producers.”
Lafontaine intends to conduct a sensory panel with the various beers produced from rice malt. He and Guimaraes have noticed, for example, that some aromatic varieties of rice produced elevated levels of diacetyl, which has a buttery popcorn aroma often considered an off flavor in beer.
“As a sneak peak of the next part of this study, I can say that the rice varieties had many different and interesting aromas and flavors,” Guimaraes said. “I firmly believe they have great potential either as a standalone raw material or in conjunction with barley malt.”
The rice varieties were malted in small quantities during the study using techniques comparable to industry standards. With each small test batch, the researchers measured protein content, enzyme levels and other characteristics important to brewing. Lafontaine’s lab is licensed and bonded as the U of A Beverage Development Facility with an electric, 15-gallon brewing system to provide hands-on experience to students in the University of Arkansas Certificate of Proficiency in Brewing Science program.
Collaborators on the study included rice breeders at the Division of Agriculture’s Rice Research and Extension Center, researchers with the Arkansas Agricultural Experiment Station’s Rice Processing Program, the U.S. Department of Agriculture’s Dale Bumpers National Rice Research Center in Stuttgart, and Versuchs-und Lehranstalt fΓΌr Brauerei in Berlin, Germany.
The authors recognized the Arkansas Rice Research and Promotion Board for supporting the research.
To learn more about Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website: https://aaes.uada.edu. Follow us on π at @ArkAgResearch and Instagram at @ArkAgResearch.
To learn about Extension Programs in Arkansas, contact your local Cooperative Extension Service agent or visit https://uaex.uada.edu/. Follow us on π at @AR_Extension.
To learn more about the Division of Agriculture, visit https://uada.edu/. Follow us on π at @AgInArk.
About the Division of Agriculture
The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on five system campuses.
The University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services without regard to race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an Affirmative Action/Equal Opportunity Employer.
TEST BATCHES — Beers made with malted rice are part of a study led by the University of Arkansas System to test the malting qualities of 19 U.S. rice varieties.
CREDIT
University of Arkansas System Division of Agriculture photo by John Lovett
JOURNAL
Beverages
ARTICLE TITLE
Investigating the Malting Suitability and Brewing Quality of Different Rice Cultivars
Researchers Look to Rice for ‘Clean Label’ Ingredients
Using polyphenol-protein interactions can provide foods with clean label characteristics
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CLEAN LABELS — ANNEGRET JANNASCH, LEFT, AND YA-JANE WANG, PROFESSOR OF CARBOHYDRATE CHEMISTRY, ARE LOOKING AT THE COMPONENTS OF PIGMENTED WAXY RICE TO SERVE AS A "CLEAN LABEL" STARCH STRENGTHENER.
view moreCREDIT: UNIVERSITY OF ARKANSAS SYSTEM DIVISION OF AGRICULTURE PHOTO BY ARIEL ROMERO
FAYETTEVILLE, Ark. — Naturally occurring polyphenols and proteins from pigmented waxy rice may help starch ingredients improve texture without any chemical modification — a change some consumers may welcome, said Ya-Jane Wang, professor of carbohydrate chemistry.
Chemically modified starch is a common thickener in soups and other foods. Without modification, starch breaks down during high-temperature and high-shear food processing and no longer functions properly as a thickening agent.
As consumers express concerns over chemically modified ingredients, Wang is looking at alternatives. With the help of a $400,000 U.S. Department of Agriculture National Institute of Food and Agriculture grant awarded in 2023, Wang is exploring how to use polyphenols and proteins naturally present in pigmented waxy rice as a natural starch strengthener.
Polyphenols are a micronutrient that naturally occur in plants. She used pigmented waxy rice because the presence of polyphenols in the rice and the polyphenol-protein interaction that arises. “Waxy” rice is also known as “sticky” or “sweet” rice due to its low level of amylose, one of the ingredients that make up starch. Higher levels of amylose cause the rice to separate and become fluffy, whereas lower levels of amylose produce higher viscosities. Polyphenol-protein interactions naturally present in the pigmented rice aid in retaining a food’s viscosity, or thickness, during the cooking process.
Wang conducts research for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture. Her collaborators on the research include Annegret Jannasch, a doctoral student in the Dale Bumpers College of Agricultural, Food and Life Sciences, who works under the direction of Wang; Anna McClung, a recently retired research geneticist at the Dale Bumpers National Rice Research Center; Sun-Ok Lee, associate professor of nutrition for the experiment station; post-doctoral researcher Zeina Alraawi; and Suresh Thallapuranam, Cooper Chair of Bioinformatics Research and professor of biochemistry.
Wang, Jannasch and Lee work in the food science department in the Bumpers College. Thallapuranam is joining the team from the chemistry and biochemistry department in the Fulbright College of Arts and Sciences.
McClung provides the researchers with pigmented waxy rice samples.
“We propose that pigmented waxy rice can function like chemically modified starches but without the use of chemicals, so it will be a clean label ingredient,” Wang said.
“Clean label” is not a scientific term, but the food industry, academics and consumers define the phenomenon as choosing foods with easy-to-recognize ingredients and no artificial ingredients or synthetic chemicals, according to the Institute of Food Technologists.
Consumer perception
In recent years, consumers have raised concerns about ingredients used in food production, Wang noted. Some consumers aim to consume only minimally processed food.
The idea of minimal processing varies from person to person, Wang said. Some consumers prefer wheat flour, but others might consider wheat flour too processed and consume whole wheat flour instead.
“A lot of processed food is really for preservation or convenience,” Wang said. Food products such as ham, pickles and TV dinners, for example, are processed to help simplify food preparation for the consumer and to extend shelf life.
Wang’s research may alleviate these concerns related to modified starch.
Many foods contain modified starch, which is chemically altered to improve processing and storage stability, Wang said. Starches function as thickening agents to improve the texture and consistency of food products.
The inspiration for this project came from Wang’s recent research that explored the possibility of utilizing the interactions among polyphenols, protein and starch in pigmented waxy rice to increase satiation, the feeling of fullness. In that original project, Wang found that the pigmented waxy rice’s unique interactions between polyphenols and proteins allow starch to swell more in an acidic condition that simulates gastric environments.
“Starch, when it swells, is like a balloon — it becomes bigger and bigger,” Wang said. During food processing, “the temperature, the shear, the high acidity will completely break down the balloon. You want the balloon to swell more — that is how you create the viscosity — but you don’t want it to swell too much. The polyphenol-protein interactions help to maintain the starch structure so it will stay at that stage.
“That is why you can use starch to thicken any soup because the starch can swell more than 10 times its volume, but once it gets to that stage, it becomes very fragile,” she said.
Outside of consumer perception, Wang said that applying this pigmented waxy rice, as opposed to using modified starch, could provide additional environmental and health benefits.
With any chemical modification comes a residue, Wang said, so using a naturally occurring starch with these properties eliminates that concern. Polyphenols are present in many berries and vegetables, and a high amount of polyphenols are known to have anti-oxidant, anti-inflammatory and antidiabetic properties.
PIGMENTED WAXY RICE — Annegret Jannasch holds a dish of pigmented waxy rice, which research is showing to aid in strengthening starch.
CREDIT
University of Arkansas System Division of Agriculture photo by Ariel Romero
A three-phase approach
The research will take place in three phases. Wang and her team have finished the first phase, which evaluated pigmented waxy rice samples and their contents and compositions of proteins, starch and polyphenols. A research article titled “Elucidating the effect of polyphenol-protein interactions on rheological properties of purple waxy rice” was published in the Journal of Cereal Science this month.
The next phase will determine the nature of the polyphenol-protein interactions in pigmented waxy rice. Interactions between polyphenols and proteins involve chemical bonds linking two molecules, and it is important because a strong bond helps maintain granule integrity under high shear, temperature and acidic conditions, Wang said.
Finally, the researchers will apply thermal processing conditions to alter the extent of polyphenol-protein interactions so the resulting products will produce a wide range of viscosities for different applications.
“We really want to see the possibility of commercializing the resulting technology,” Wang said. “We want to see if any companies are interested and work with them.”
Companies using this to make cereals, pudding, or pasta is something that Wang hopes to see.
Wang will share an update on this research at the USDA-NIFA project director meeting in Amherst, Massachusetts, on June 17-18.
To learn more about Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website: https://aaes.uada.edu. Follow us on π at @ArkAgResearch and Instagram at @ArkAgResearch.
To learn about Extension Programs in Arkansas, contact your local Cooperative Extension Service agent or visit https://uaex.uada.edu/. Follow us on π at @AR_Extension.
To learn more about the Division of Agriculture, visit https://uada.edu/. Follow us on π at @AgInArk.
About the Division of Agriculture
The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on five system campuses.
The University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services without regard to race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an Affirmative Action/Equal Opportunity Employer.
JOURNAL
Journal of Cereal Science
ARTICLE TITLE
Elucidating the effect of polyphenol-protein interactions on rheological properties of purple waxy rice
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