INFORM September 2024

inform September 2024 Volume 35 (8)

FATS from PLANTS

ALSO INSIDE: Tuning oleogels using capillary networks Insect oils and their lipid composition Ketogenic diet and mental health

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September 2024 inform

Plant-based fat replacements for alternative meats Duplicating the sensory pleasure of a drippy burger or a sizzling steak in a plant based alternative meat takes the ingenuity of food scientists. Read about the latest techniques they are using to mimic solid fats using healthier and more sustainable plant-based oil substitutes. 8 FEATURES

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Capillary networks: Bridging the gaps in edible oleogels This story describes how oleogels can be tuned to achieve the specific functional properties necessary for a particular food application. The author describes how particles suspended in oil provide soft materials with an adjustable capillary network. A sustainable approach to functional lipids A recently published review in the Journal of the American Oils Chemists’ Society discusses unique sources of edible oils that could satisfy a rising demand for sustainably sourced food lipids. The authors present both microbial and insect oils; however, this excerpt of the article focuses just on insects and their lipid composition. Pilot study shows ketogenic diet improves severe mental illness A team of US researchers, led by scientists at Stanford, conducted a small clinical trial that determined a ketogenic diet restores the metabolic health of patients with mental illness and improves their psychiatric condition. Read about the study’s findings in this story.

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CONTENTS

4 Index to Advertisers 19 AOCS Meeting Watch

5 Editor’s Letter 6 Division Update

26 AOCS Journals 27 Regulatory Review 30 Extracts & Distillates

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ADVERTISING INSTRUCTIONS AND DEADLINES Closing dates are published on the AOCS website (www.aocs.org). Insertion orders received after closing will be subject to acceptance at advertisers’ risk. No cancellations accepted after closing date. Ad materials must be prepared per published print ad specifications (posted on www.aocs.org) and re ceived by the published material closing dates. Ma terials received after deadline or materials requir ing changes will be published at advertisers’ risk. Send insertion orders and materials to the email address below. NOTE: AOCS reserves the right to reject adver tising copy which in its opinion is unethical, mislead ing, unfair, or otherwise inappropriate or incompat ible with the character of INFORM . Advertisers and advertising agencies assume liability for all content (including text, representation, and illustrations) of advertisements printed and also assume responsi bility for any claims arising therefrom made against the publisher. AOCS Advertising: Travis Skodack, Director Membership Phone: 1-217-693-4897 Email: travis.skodack@aocs.org Formerly published as Chemists’ Section , Cotton Oil Press , 1917–1924; Journal of the Oil and Fat Indus tries , 1924–1931; Oil & Soap , 1932–1947; news por tion of JAOCS , 1948–1989. The American Oil Chem ists’ Society assumes no responsibility for statements or opinions of contributors. INFORM (ISSN: 1528-9303) is published 10 times per year in January, February, March, April, May, June, July/August, September, October, November/ December by AOCS Press, 3356 Big Pine Trail, Ste C&D, Champaign, IL 61822 USA. Phone: +1 217-359 2344. Periodicals Postage paid at Champaign, IL, and additional mailing offices. POSTMASTER: Send ad dress changes to INFORM , PO Box 7230, Champaign, IL 61826 Subscriptions to INFORM for members of the American Oil Chemists’ Society are included in the annual dues. An individual subscription to INFORM is $195. Outside the U.S., add $35 for surface mail, or add $125 for air mail. Institutional subscriptions to the Journal of the American Oil Chemists’ Society and INFORM combined are now being handled by Wiley. Price list information is available at http://olabout. wiley.com/WileyCDA/Section/id-406108.html. Claims for copies lost in the mail must be received within 30 days (90 days outside the U.S.) of the date of issue. Notice of change of address must be received two weeks before the date of issue. For subscription inquiries, please contact Julie May at AOCS, julie.may@aocs.org. AOCS membership information and applications can be obtained from: AOCS, PO Box 7230, Champaign, IL 61826 USA or membership@ aocs.org. NOTICE TO COPIERS: Authorization to photo copy items for internal or personal use, or the inter nal or personal use of specific clients, is granted by the American Oil Chemists’ Society for libraries and other users registered with the Copyright Clearance Center (www.copyright.com) Transactional Report ing Service, provided that the base fee of $15.00 and a page charge of $0.50 per copy are paid directly to CCC, 21 Congress St., Salem, MA 01970 USA.

AOCS MISSION STATEMENT AOCS advances the science and technology of oils, fats, proteins, surfactants, and related materials, enriching the lives of people everywhere.

inform International News on Fats, Oils, and Related Materials ISSN: 1528-9303 IFRMEC 35 (8) Copyright © 2013 AOCS Press

EDITORIAL ADVISORY COMMITTEE

Julian Barnes Etienne Guillocheau Jerry King

Gary List Thais L. T. da Silva Warren Schmidt Raj Shah

Ryan Stoklosa Ignacio Vieitez Bryan Yeh

AOCS OFFICERS PRESIDENT: Tony O’Lenick, SurfaTech, Lawrenceville, Georgia, USA VICE PRESIDENT: Gerard Baillely, Procter & Gamble, Mason, Ohio, USA TREASURER: Greg Hatfield, Bunge Limited, Oakville, Ontario, Canada SECRETARY: Fabiola Dionisi, Societe’ Des Produits Nestlé - Nestlé Research, Lausanne, Vaud, Switzerland PAST PRESIDENT: Grant Mitchell, Salas O’Brien, Cincinnati, Ohio, USA CHIEF EXECUTIVE OFFICER: Patrick Donnelly

AOCS STAFF EDITOR-IN-CHIEF: Rebecca Guenard MEMBERSHIP DIRECTOR: Travis Skodack

PAGE LAYOUT: Moon Design

The views expressed in contributed and reprinted articles are those of the expert authors and are not official positions of AOCS.

INDEX TO ADVERTISERS *CPM Crown. ......................................................................................................... C4 *Desmet USA, Inc................................................................................................... C2 *French Oil Mill Machinery Co................................................................................. 1 Koerting Hannover AG . .......................................................................................... 7 *Myande Group Co. Ltd. . ....................................................................................... 17 *Oil-Dri Corporation of America . ........................................................................... C3 Pope Scientific, Inc. . ............................................................................................. 11 Sharplex Filters (India) Pvt. Ltd. ............................................................................ 13 *Corporate member of AOCS who supports the Society through corporate membership dues.

EDITOR’S LETTER

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New fats

In recent years, with increased consumer awareness about the relationship between excess fat intake and chronic disease, the research of many AOCS members has focused on how to replace these less healthy fats. Our members also study ways to offer an alterna tive fat to consumers who do not eat animal by-products. And of course, some are working on solutions that address both types of fat replacement problems. This issue of INFORM covers stories about the latest science to develop high-quality fat replacements. It is still a technical challenge to completely simulate the enjoyment we experience eating natural fat in foods. Fat is a critical component of our eating experience. Simply reducing the fat content of a food causes changes in its physical, chem ical, physiological and sensory properties. In our cover story, we

“Discover the latest techniques they are using to mimic solid fats with healthier and more sustainable plant-based oil substitutes.”

mealworms and black soldier fly larva. The authors discuss how these unexpected sources of food lipids can be sustain ably raised and represent a new source of fats consumers should consider. Finally, we have a story on a groundbreaking pilot study led by a team at Stanford University Medical School. This study reveals the promising effects of a ketogenic diet on severe mental illness. The small clinical trial found that a ketogenic diet can restore metabolic health in patients with mental ill ness, significantly improving their psychiatric condition. The implications of these findings could be far-reaching, offer ing new hope for individuals struggling with these debilitating conditions. We hope these stories provide valuable insights into the remarkable advancements in food science particularly for those of you whose job function is outside of this field. Thank you for reading, and we look forward to sharing more of every thing that AOCS has to offer in our next issue.

explore the fascinating world of plant-based fat replacements for alternative meats. Crafting a plant-based burger that rivals the sensory experience of a tra ditional beef patty is no small feat. Our feature article delves into the ingenuity of food scien tists who are at the forefront of this challenge. Discover the lat est techniques they are using to

mimic solid fats with healthier and more sustainable plant based oil substitutes. Their innovations promise to redefine our culinary expectations. Our next feature takes an in-depth look at capillary net works in edible oleogels. These unique formations could alter how we achieve specific functional properties in various food applications. Learn how particles suspended in water or oil can create soft materials with adjustable capillary networks, offering new possibilities for texture and stability in our favorite foods. Then we consider a unique source of edible oils, insects. Our third feature is an excerpt from a review article recently published in the Journal of the America Oil Chemists’ Society . The article reports on the lipid composition of insects like

Yours in science,

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The Edible Applications Technology (EAT) Division is made up of professionals in the processing and utilization of lipids with a primary focus on food applications. Each division sponsors a Student Poster Competition held at the Annual Meeting. This month’s division spotlight focuses on the EAT student winners for 2024. the Winners of This Year’s Student Poster Competition FIRST PLACE AWARD “Screening of emulsifying peptides derived from brewers’ spent grain” Rasmus Mikkelson, PhD Student, National Food Institute, Technical University of Denmark Rasmus’ poster presented results from experiments on screening peptides derived from brewers’ spent grain (BSG). The poster demon strated the potential that BSG protein and peptides have as a new emulsifying ingredient. His team used a previously devel oped open-source bioinformatics model that can predict emul sifying peptides embedded in proteins. He wanted to show Edible Applications Technology Division Features

YOUR AOCS COMMUNITY

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that the model can aid in the screening process of new raw materials and limit the need for time consuming screening procedures. Rasmus’ PhD research focuses on the use of BSG as both antioxidant and emulsifying ingredients. He is working to understand the interfacial behavior of especially low-fat, oil in-water emulsions and how different peptides influence the interface characteristics. Rasmus will complete his PhD in the summer of 2025 and is seeking a post-doctoral position or an opportunity in industry. SECOND PLACE AWARD “Modelling crystalline nanoplatelets in tri glyceride systems: A new shape-dependent USAXS model” Ivana Penagos, PhD Student, Gent University, Belgium Ivana’s poster demonstrated the develop ment of a new model to interpret ultra small angle X-ray scattering (USAXS) data for triglycerides. She introduced the model during an oral presentation in the EAT session on fat crystallization, highlighting its potential to reveal detailed insights into the structural formation of triglycerides. Anticipating that some attendees would be interested in the technical aspects, Ivana also created a poster that covered the model’s complexities. Ivana’s PhD research aims to enhance the understanding of triglyceride structures at different length scales. Although progress has been made toward understanding lipid systems, predicting the macroscopic behavior of triglycerides is still unclear; especially regarding how different units form and assemble under different processing conditions. Ultimately, Ivana hopes that by improving our understand ing of how lipids self-assemble, her research will help design better edible lipid systems from the bottom up. Ivana is currently finishing her PhD at Ghent University. After graduation, she hopes to transition into an R&D role in the industry. Ivana is particularly interested in remaining in the food sector; although, she is still exploring which specific role would be the best fit. AUDIENCE CHOICE AWARD

hensive method for assessing the plasticity of margarine, a crucial factor in its texture and consumer appeal. Arpita pre sented a specific study on the sensitivity of a standardized approach (LAOS method) that can be universally adopted. She hopes the findings will not only enhance quality control and product consistency but also facilitate innovation in the devel opment of new margarine and related products. In the near future, Arpita plans to focus on research ing emerging fat sources and their applications. She wants to become an expert in developing new fat-based products and optimizing their production processes. In general, she is inter ested in topics which are applicable in the real world, that bring value to both academia and industry.

STUDENT POSTER COMPETITION Look for details on how to submit a poster for the Student Poster Competition in 2025 after the call for papers opens in September. https://annualmeeting. aocs.org/student-competitions

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“Investigating Rheological Method (LAOS) Responsiveness in Intricate Food Systems” Arpita Chakraborty, PhD Student Researcher, Gembloux Agro-Bio Tech, University of Liege, Belgium Arpita’s poster showed how although margarine has been a staple product for

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The scale at which livestock is currently raised in factory farms—and the methodology used to raise it—generate meat that is bad for the environment, bad for the animals, and bad for the people who eat them. Alternative, plant-based meats are providing consumers with the experience of eating meat while avoiding some of these pitfalls, but they will only be successfully insofar as they can duplicate the sensory pleasure associated with a drippy burger or a sizzling steak. And much of that pleasure comes from animal fat. replacements for alternative meats Diana Gitig Plant-based fat

In her bestselling cookbook Salt, Fat, Acid, Heat , Samin Nosrat writes that the aromatic molecules that give each kind of meat its distinctive flavor tend to be fat rather than water soluble. Hence, an animal’s fat actually tastes more like the animal than its meat does. As meat cooks, the solid fat within it slowly renders, keeping the meat juicy. The flavor ful liquid fat that remains coats the tongue, allowing the flavors to linger. Mimicking the experience by generating the mouthfeel that consum ers want and expect is hard–so hard, in fact, that some alternative meat companies are just adding animal fat back into their plant-based meats. All the while, food scientists are working toward other solutions. The goal is to get plant-based, liquid oil to act like a solid animal fat. This is difficult for the same reason that it is desirable: animal fats contain cholesterol and around 40 percent saturated fatty acids. Plant-based oils are usually around 10-20 percent saturated fatty acids. Coconut oil, for example, is frequently used to substitute ani mal fat in alternative meat products since it is 90 percent saturated fat and solid at room temperature. However, it melts quickly at only 24 °C, since it is rich in medium-chain saturated fatty acids, and leaks out of the meat product during cooking, leaving it dry. It is also unsustainably sourced from the rainforest and often mixed with methylcellulose to lend hardness. “Who wants to eat that,” said Alejandro G. Marangoni, food science professor at the University of Guelph, Canada. According to researchers, there are three primary options for plant based fat replacements for meat alternatives. Oleogels are liquid oils that have been solidified using physical methods, such as adding a structuring or solidifying agent—typically a small molecule that crystallizes. Emulsion gels add an additional phase (usually water) to the system. In emulsion gels, only one phase is in a gel state, for example oleogel droplets within a water phase. Finally, there are bigels, wherein both the water phase and the oil phase are gels. Polysaccharides and proteins—molecules that

• To improve the sustainability and health of the modern food supply, food scientists are experimenting with ways to replace animal fats with plant-based lipids. • Consumer concerns surrounding sources like palm oil and coconut oil have resulted in researchers focusing on oils rich in unsaturated fatty acids. • Here we present some highlights of research efforts on emulsions and structured oils. • And we conclude with some examples of research that successfully resulted in a commercialized product.

FAT SCIENCE

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impact the product’s flavor and nutrition profile—can be used as structuring agents in the water phase. Here we describe the latest research in plant-based fat replacements for a variety of food applications. PLANT FAT + ANIMAL PROTEIN A team of scientists led by Supratim Ghosh , professor at the University of Saskatchewan, Canada have been addressing the challenge of replacing the animal fat in real meat with a plant based fat. The motivation, of course, being the decades of research showing that eating a lot of meat increases our risk of developing obesity, diabetes, and cardiovascular disease, due to high saturated fat consumption. The team focused on emul sion gels as a potential fat carrier, because of their favorable rheology and texture. The researchers developed soon-to-be patented emulsion gel made of faba bean protein isolate, canola oil,

and water. They used it to completely replace the pork back fat in bologna sausages made with lean ground pork. This hybrid bologna thus kept the nutritional benefits of being high in animal protein but was lower in fat than the original sausage. A panel of sixty volunteers tasted the hybrid bologna and reported liking it slightly less in terms of color, texture, flavor and juiciness with similar saltiness compared to the animal fat containing bologna. They ranked it overall as “slightly accept able,” while the meat controls with animal fat were “moder ately acceptable.” Ghosh and his colleagues attribute this to the fact that the hybrid sausage is much paler in color, since the emulsion gel itself reflects light. Phyllis Shand, professor emeritus at the University of Saskatchewan and a member of the research team said, “the paler color could potentially be a positive in a chicken-based product. It all depends on the final application.” Major classes of fatty acids in conventional vs. hybrid bologna Conventional low-fat bologna Hybrid bologna Saturated fatty acid (%) 43.4 7.5 Mono-unsaturated fatty acid (%) 46.5 65.4 Poly-unsaturated fatty acid (%) 10.1 27.1

Composition data comparing conventional low-fat bologna with hybrid bologna where the pork fat has been removed and replaced with an emulsion gel made from vegetable oil and protein.

Hybrid meat formulations with equivalent fat composition

Conventional low-fat bologna Hybrid bologna

Ingredients (wt%)

Lean pork

50.0 11.7 36.0

50.0

Pork backfat

-

Water

18.0

Plant-based emulsion gel

-

30.3

Other ingredients

2.3

1.7

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Conventional low-fat bologna

Hybrid bologna

Images comparing conventional low-fat bologna with hybrid bologna showing the paler color due to the emulsion gel.

A separate research group used a bigel, instead of an emulsion, to study replacing animal fat in food products. The team at Iowa State University, Ames, Iowa used 92.5 percent high-oleic soybean oil and 7.5 percent rice bran wax. Although their plant-based fat has a different composition, they reported similar results. When the bigel was used to replace fat in pork sausages the finished products were paler than con trols containing animal fat. However, in this case there were also reports of less flavor and aroma. Given that their hybrid bologna’s properties were mostly favorable, Ghosh anticipates that the emulsion has commer cial potential with meat processing companies. Shand says that spices can be added to enhance the color of the emulsion gel to look more appealing to consumers depending on the appli cation. Next, the team, including doctorial student Oluwafemi Coker, plans to test the emulsion in beef burgers and break fast sausage patties. They have no immediate intentions to mix it with a plant-based alternative meat, but Ghosh says it could find use there. PLANT FAT + PLANT PROTEIN From Marangoni’s perspective fat mimetics should be approached in an entirely different way. It is not just animal fat that meat analogs need to mimic, he says. It is the entire struc ture of adipose tissue . To make plant products mimic animal adipose tissue Marangoni’s lab uses decellularized plant tissue. Adipose tissue is composed of adipocytes surrounded by an extracellular matrix made of collagen protein and polysaccharides that create a scaf

fold for the fat-containing adipose cells. This is why upon heating adipose tissue in meat retains its form while oleogels lose theirs; plant oils do not have a similar protein structure to contain them. But plants do have cellulosic tubular scaffolds. Marangoni’s idea was to use such scaffolds in the form of freeze-dried carrot or broccoli tissue and then fill them with shea and palm olein. Enzymatic glycerolysis of these plant oils converts their native triacylglycerols into more structured par tial glycerides. In a nutritional bonus, filling the scaffold with oleogel rather than oil allows the structure to hold while con taining less fat. His lab is now in a partnership with STARS and Protein Industries Canada to make plant-based burgers. San Fransico, California based start-up company, Lypid , has also developed a vegan fat based on the adipose tissue concept. PhytoFat™ is a microencapsulated ingredient cur rently being used in alternative meat products. “This creates a lot of small droplets containing plant-based liquid oil—canola or soybean—but since they are encapsulated in a different food, they can handle high heat, like a solid ani mal fat,” said Michelle Lee, co-founder and chief technology officer. “The encapsulation recreates the adipose cells that are dispersed throughout meat tissue, and during chewing the oil leaks out to create that juicy mouthfeel.” The outer shells of the capsules, which she would only divulge “are made with food ingredients that have emulsifying capabilities,” do not break down until 200-250 o C, but their for mulation allows Lypid’s research team to adjust their melting point and create different textures just through physical mod ifications. About 50 percent of the capsule is oil, so it is lower

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in calories than animal fat. And since the oil is protected from heat, flavorants and nutrients can be added and retain their potency. Lypid makes plant-based pork belly slices. According to Lee, they are the only multitexture plant-based meat on the market. But, for now, they only sell to food service, not directly to consumers. Their products are served in restaurants in Taiwan and California. PLANT FAT + CULTURED PROTEIN Marcelle Machluf is a professor of biotechnology engineering at The Technion Israel Institute of Technology in Haifa, Israel. As head of The Lab for Cancer Drug Delivery & Cell Based Technologies her lab made a targeted drug and gene delivery system by draining the contents of mesenchymal stem cells, leaving only the membranes, and then shrinking the mem brane shells down to nano size. But when she became Dean of the faculty and got more contact with her food engineering colleagues, she realized that her technology could be applied to the scalable production of healthier meat alternatives. “Mammalian cells are mammalian cells,” Machluf said. “We know how to engineer them.” Her lab made cultured meat tissue by expanding bovine mesenchymal stem cells on edible chitosan collagen microcar riers. But she knew her product would not mimic meat without fat, so she teamed up with Maya Davidovich-Pinhas, associate professor of biotechnology and food engineering (and 2024 winner of the AOCS Edible Applications Technology Division Outstanding Achievement Award). Davidovich-Pinhas developed an oleogel-based fat substi tute to help achieve the taste, texture, and mouthfeel of meat. Her lab used a combination of direct and indirect methods to make their fat substitute. Oil droplets were structured with glycerol monostearate (GMS) in a protein-aqueous solution using an emulsification procedure, followed by lyophilization. The ultimate formulation of their emulsion was a 20 weight percent canola oil and 4.5 weight percent chickpea protein dispersion. After homogenization, their fat substitute looked, felt, and behaved like beef fat—even upon cooking—and it reduced more than 65 percent of the saturated fatty acid con tent compared to beef while increasing the amount of health ful omega-6 and omega-3 fatty acids. They combined Machluf’s cultured tissue with Davidovich Pinhas’ fat substitute to make a ground beef analog. Machluf said that “it tastes great, is more nutritious than meat, and can hold its shape and texture during frying and cooking.” Davidovich-Pinhas noted that their oleogel-based fat substi tute can be loaded with different macro and micronutrients to improve its nutritional profile. And since protein based oleo gels are relatively thermostable, their melting behavior can be tailored to different cultured meat products by altering the type and amount of oil structuring agent. Machluf applied for a patent and founded a company, Meatafora. She has plans to make ground chicken and fish products as well, and to sell the chitosan collagen microcarriers system to others who want to cultivate their own cells as a protein source.

A piece of pork belly created by Lypid with PhytoFat™ incorporated into the product.

PLANT FAT + ANY PROTEIN KaYama Foods, based in Tel Aviv, Israel, was co-founded by Gad Harris, a chemical processing and environmental engineer, and lifelong vegan who worked in oil recycling and in an alternative protein company before starting this alternative fat company. “Fat has a biochemical role to play during cooking,” he said. “It should be present and free to participate in reactions with proteins and other ingredients to generate flavor and aroma compounds. If it is bound up in an emulsion, it is not free to take part in those reactions.” Moreover, he notes, the excess water in emulsions hinders these vital reactions. KaYama’s product is thus not an emulsion. It is a struc tured plant oil—sunflower, canola, soy, olive, whatever healthy local oil you like, plus phytonutrients. It does not involve water, protecting the fat from undesirable oxidation and leaving it free to react during cooking. KaYama’s patented formula pro cess does not change the chemical structure of the oil, but gives it a physical structure that retains its healthful qualities while allowing it to act like animal fat. As Harris put it, KaYama’s technology “decouples the degree of fat saturation from its solid structure and function ality.” And since their goal is maximal health and sustainability impacts, they hope to sell their alternative fat product to any food processor to mix with whatever type of protein best suits their need: plant-based, fermented, or cultivated. To address the global challenges of human health, food insecu rity, and climate change, food science researchers are devel oping innovative ways to replace saturated fat and promote protein alternatives based on plant, cell culture, and fermen tation. According to experts, within two decades 60 percent of meat sold globally will be from an alternative protein source (https://tinyurl.com/4u3w3anc). As you have read, AOCS mem bers are a key component to achieving that future. Diana Gitig earned her PhD in cell biology and genetics from Weill Cornell Graduate School of Medical Sciences in New York City. She writes about cell and molecular biology, immunology, neuroscience, and agriculture for arstechnica.com.

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Capillary networks:

Bridging the gaps

in edible oleogels Selvyn Simoes

Airy croissants, tender biscuits and luxurious chocolate all have one thing in common: solid fat. In croissants butter is laminated into sheets between layers of dough, giving it its airy and flaky texture. Butter coats flour particles in biscuits preventing hydration and gluten formation producing ten derness. Chocolate is about 30 percent cocoa butter and when tempered properly melts in the mouth. These examples illustrate the functional aspects of solid fat like plasticity, barrier properties, and melting temperature. The desirable attributes of these and many other foods rely on the structural contribution of solid fat. But the growing link between excessive solid (saturated and trans ) fat consumption has led to governments limiting their use in formulations and the drive to find alternatives that produce the same functions of solid fats without the nega tive health impacts (https://tinyurl.com/295c83ct). Accompanying a global cocoa shortage caused by changing growing sea sons because of climate change and increasing supply costs, the demand for functional solid fat alternatives continues to grow worldwide. (https://www. jpmorgan.com/insights/global-research/commodities/cocoa-prices).

• Oleogels are a promising alternative to solid fats, imparting solid-like properties on oils without the associated health risks of saturated fats. • However, they are not a one-for-one replacement of a fat’s functional properties and have experienced slow uptake by the food industry. • Particle suspensions can gel edible oils and offer a new means for tuning oleogel functional according to the food application. • This innovation expands the field

of oleogelation and offers an opportunity to create new soft materials.

No data 0g

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Fat supply delivered to households per capita in 2021. Does not indicate consumption nor account for food waste. Source: https://tinyurl.com/2kzwdpyt

SOFT MATERIALS

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OIL BEHAVING LIKE SOLID FAT An oleogel is a liquid oil that has been structured through the formation of an internal network. Primarily composed of liquid oil, they do not impart the negative health effects of solid fat, yet the gelling network gives the material solid-like properties. These solid-like properties are directly related to the strength of the network formed by the gelling agent. Since the early 2000s when Gandolfo, Bot and Flöter (https://doi.org/10.1007/ s11746-004-0851-5) used small molecules (fatty acids, fatty alcohols and their mixtures) to gel edible oils, the field of oleo gelation has exploded with new modes of gelation being dis covered each year. Simply forming an oleogel is not enough to replace solid fat. In fact, replacing one solid fat with another in food formulation is unlikely to produce the desired effects of the original fat. This is because each fat has specific properties based on its composi tion, like melting temperature and morphology (crystal shape). To complicate this further, fats are polymorphic which means that they can crystallize in several crystal structures, each with a distinct melting temperature and crystal morphology. To replace solid fats with an oleogel, understanding the structure-function relationships in each material is imperative. The most widespread gelator for oils are natural waxes, such as bee, rice bran, or candelilla which are upcycled, waxy byproducts of current agricultural processing. These waxes recrystallize to form an interconnected network of wax crys tals and gel at a concentration as low as one percent. However,

North America

Europe

Oceania

South America

World

Asia

Africa

140g

120g

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20g

0g

1961

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Increase in average fat supplied per household between 1961 and 2021. Source: https://tinyurl.com/2kzwdpyt

these gels are delicate and leak liquid oil after the network is broken during spreading, scooping, or mixing. Adding more wax improves the structural and oil binding properties, but gives the oleogel a waxy mouthfeel, increases the melting tem perature of the gel, and imparts off flavors. In addition, the interaction of oleogels with particles and other components of a food matrix is not well understood, but relevant given the compositional variety of formulations. So, how do we face

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Examples of capillary suspensions made with increasing amounts of water. Source: Koos, E., JCOCIS , 19, 6, 2014.

these challenges, and produce functional solid fat alternatives? The solution may lie in food particles. STRUCTURING OILS WITH PARTICLES Food particles come in all shapes and sizes, such as proteins, sweeteners, and starches. But most particles cannot gel oil on their own since they lack the ability to aggregate into strong networks. Even chocolate, which is more than 60 percent par ticles of sugar, cocoa, and milk powder, flows like a viscous fluid when the solid fat is melted. Capillary suspensions form when particles are suspended in a solvent and a secondary immiscible fluid forms the bridges between particles, creating a network that gives the oil its solid-like properties. Hence, by adding water to food particles in oil, we can give the particles and the oil structure.

This is conceptually similar to the way sandcastles hold their shape. Dry sand flows as a powder, but if the sand is wet it can be molded because the water forms a bridges between the grains of sand. Capillary suspensions were first reported in Science (2011) by Erin Koos and Norbert Willenbacher (https:// doi.org/10.1126/science.1199243). They suspended 11 percent (by volume) calcium carbonate particles in an oily organic sol vent and water at 0.1 to 0.5 weight percent. Koos and other authors went on to catalogue capillary suspensions made with variables like different particle shapes, majority and secondary fluids, particle roughness, mixing conditions, and order of addi tion for different material applications from ceramics to foods. By adding a small amount of water to particles in oil, the water forms bridges between the particles allowing them to form a capillary network. For polar particles, water will have limited interaction with the oil and wet the surface of the polar particles, producing concave bridges and forming a network. For non-polar particles in oil, neither the particles nor the oil prefers to associate with the water the bridges. The result ing bridges are convex and the water droplets are shielded from contact with the oil phase by the particles. In both cases the water causes the particles to cluster and connect throughout the oil to form the capillary network, preventing sedimentation. Capillary suspensions can form with particle fractions as low as 11 percent and become firmer with increasing parti cle fraction as more bridges are formed. The versatility of this gelation method allows researchers to modulate a network’s strength by altering the particle fraction and the particle polar ity. The capillary network’s strength and morphology changes with bridging fluid’s properties and concentration. For parti cles in oil bridged by water, adding more water causes multiple particles to be connected by a singular meniscus. Compared to clusters made of the same number of particles but discrete bridges, the continuous meniscus produces stronger bridges and firmer gels. Although, adding too much secondary fluid will cause the particles to be swept into spherical agglomer ates which weaken network strength. Capillary networks can also recover their structure after a sufficient rest period. The networks nearly return to their original gel strength which may prove useful in applications where both structure and workability are required (https:// doi.org/10.1007/s00397-017-1040-1). For comparison, wax oleogels form the best networks after recrystallization where

For water-bridged particles in oil:

Polar particles

Pendular bridges

Particle clusters

Network formation

Non-polar particles

Capillary bridges

Polar particles

Non-polar particles

Examples of particle clusters that aggregate to form capillary net works and corresponding micrographs. The water is shown in white around the spherical particles, on a (black) oil backdrop to highlight the particle networks.

18 • inform September 2024, Vol. 35 (8)

case of protein or sugars—their use in capillary suspensions may also offer unique functionalities and opportunities for exploration. Capillary suspensions have also been used as a fat alter native for baked goods. One research team made sponge cakes with whey protein-in-oil capillary suspensions. The protein enriched cakes showed similar aeration and sensory properties to the control cake made with margarine. Where other researchers found that wax oleogels produce sponge cakes with textures similar to those made with oil (https://doi. org/10.1039/D2FO00563H). HYBRID OLEOGELS But what if we combined two gelation methods to develop a new material? Capillary suspensions are promising for applica tions where air incorporation and structure are required. Yet, they lack the crystallinity to provide the barrier properties of fat. Wax oleogels produce weaker networks but offer crystal linity. In hybridizing these gelation methods, the wax gel may provide a source of crystallinity, and a barrier to bridging fluid evaporation since it gels the oil. Capillary suspension could provide gel strength and tunabil ity, altering physical properties like crystal shape and wax gel oil binding without increasing the melting temperature or impart ing off-flavors. Studying the way that crystalline networks inter act with particle networks and interfaces adds to the current understanding of both types of oil structuring and could lead to new soft material science and functional food design. Simoes and Rousseau prepared canola oil-continuous cap illary suspensions with glass particles bridged by water and gelled the oil phase with hextriacontane (C36), a hydrocarbon wax (https://doi.org/10.1039/D3SM01619F). The wax was cho sen as a control for surface active. Minor components found in natural waxes may change crystallization kinetics or inter facial properties between the oil and water, affecting capillary force. Glass particles were used as a proxy for food particles since they are non-porous, non-swelling and have a smooth surface. Glass particles are polar because of their surface alco hol groups. These groups also allow for the glass particles to be chemically hydrophobized to understand the effects of particle polarity and to compare networks using particles of the same size distribution. Without water, both polar and non-polar particles pre vented wax oleogel formation. But when wax is added to the capillary suspension a hybrid gel forms. The hybrids have unique properties when compared to a wax oleogel or a capil lary suspension. The capillary suspensions provided substantial network strength in the hybrids, increasing gel firmness. The wax network imparted some brittleness and after scooping the hybrids visually displayed decreased oil loss. The hybrids made with non-polar particles had a surprising gel strength that was greater than the sum of its parts suggesting that there was some interaction between the gelling methods. The hybrid gels showed greater gel strength with lower amounts of water. Yet, without enough water to form the capillary network no gel formed, suggesting that the capillary network is important

the crystals have sintered together. Upon shear, the network is broken and is comprised of dispersed crystal clusters that require re-aggregation through weak Van der Waal forces to reform a network (https://doi.org/10.1021/acs.jafc.5b01548). Capillary suspensions, on the other hand, merely need to have their particle clusters reaggregate to form as strong of a bridge as the original material prior to shear. In other mate rial applications like ceramics, capillary suspensions show the ability to retain their structure, resulting in enhanced proper ties. This only occurs if the network has a secondary method of curing, allowing the particles to irreversibly sinter. If the liquid bridges are a volatile fluid and evaporate, the network returns to a particle-in-oil suspension and the network loses its strength. STRUCTURING EDIBLE OILS WITH FOOD PARTICLES By using particle properties to structure oils, there is no need for additives like wax or more solid fat. Food particles have been used to make capillary suspensions for fat-free spreads and margarines. Non-polar particles like cocoa and starch (https://doi.org/10.1016/j.foodhyd.2014.01.027) and polar particles like proteins (https://doi.org/10.1016/j.food hyd.2024.110073) can give oils solid-like properties with the addition of a small quantity of water. In these cases, without the added water the suspensions would flow like a fluid instead of being spreadable. The water bridges also provide the oppor tunity to add flavors, salts, or sweeteners, that would other wise be insoluble in a lipid phase, leading to more freedom in food formula without the need for emulsifying agents. Since food particles are usually non-spherical, have com plex microstructures, and may even swell or dissolve—in the Capillary suspensions and their structures under scanning electron microscopy. Particles are depicted as grey spheres, connected by blue water bridges surrounded by a yellow oil phase. Increasing water from 3 to 9 percent promotes the formation of spherical agglomerates. Polar particles become part of the agglomerates, non-polar particles tend towards coarse Pickering-like structures, decorating the droplet exterior. Source: Simoes and Rousseau, Soft Matter , 20, 4329-4336, 2024.

inform September 2024, Vol. 35 (8) • 19

for the wax oleogel to form around the particles, but too much water is detrimental to network strength, illustrating the com plex relationship between oil, particles, wax, and water. LOOKING FORWARD A research group at Wageningen University, in the Netherlands, is investigating an oil-free capillary suspension where particles form a network with two immiscible aqueous phases (dextran and PEG) (https://tinyurl.com/2zkds3kt). Other investigators have gelled the water bridges instead of the oil phase, creating a suspension with thermally controlled rigidity. Elsewhere, when a suspension of cocoa particles is heated in water, they leak molten cocoa butter which can form capillary suspensions that solidify on cooling, creating a type of food based thermoresponsive gel. Some incredible work is being done to understand the physical properties of these soft materials and push the boundaries of their capabilities. These examples only begin to scratch the surface and by developing new structuring strate gies we can make highly tunable soft materials for functional foods and beyond. Selvyn Simoes is an early-career food chemist working on their PhD with Prof. Dérick Rousseau at Toronto Metropolitan University, Selvyn can be contacted at selvyn.simoes@hotmail.com.

AOCS EVENTS WATCH AOCS MEMBER EXCLUSIVE EVENTS October 2, 2024, 9-10:30 am CDT (Chicago, USA; UTC-5). Masterclass with Rick Theiner on Nonionic surfactants: Examining performance & properties INFORM seminars will launch in 2025. These are online, microlearning experiences designed to help you learn new skills and connect with professionals who share your interests. Check for updates in upcoming issues of INFORM, at aocs.org, or contact us at general@aocs.org, +1 217-359-2344. Here are some topics we have planned for early next year: January: Plant-based, insects, single-cell organisms, precision fermentation… Learn about the latest emerging protein sources. February: Macronutrients in shelf-stable milk alternative beverages March: Overcoming sophorolipid formulation challenges April: How to program in R for predictive modeling

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20 • inform September 2024, Vol. 35 (8)

A sustainable

approach

to functional lipids Ityotagher P. Aondoakaa and Casimir C. Akoh

Functional lipids serve as ingredients in the formulation of functional foods. While there is no universally accepted definition for functional lipids, they can be defined as a category within functional foods which share similarities with conventional lipids (edible fats/oils) in terms of appearance but distinguish themselves by demonstrating physiological benefits and/or reducing the risk of chronic diseases beyond basic nutritional functions.

Functional food production and nutritional supplements both have a strong demand for functional lipids. The World Health Organization rec ommended an annual consumption guideline of 20–25 kg for edible oils, with a notable shortfall observed in the intake of these oils in economi cally disadvantaged nations compared to the recommended threshold. Fats and oils are usually produced from plants, fishes, and animals (which represent the primary source of lipids) using conventional techniques which have been reported to be environmentally unfriendly. The persistent rise in the demand for food lipids, coupled with the inadequacy of primary sources to satisfy global need, and the overarch ing impact of climate change, underscore the need to explore renewable and sustainable sources of lipids. The quest for novel sources of edible oils, both intended for direct consumption and food processing applica tions, has substantially increased over the past decade. INSECT-BASED OILS Insect oil represents a valuable component of functional lipids. Insect derived food and ingredients have attracted significant global attention due to their ability to enhance food security, thereby reducing depen -

• The following article is an excerpt from a recent paper published in the Journal of the American Chemists’ Society. • The article discusses how lipids from oleaginous microorganisms and insect species have the potential to serve as a valuable ingredient for healthful food preparation. • This excerpt concentrates on the section of the review dedicated to insect oils.