Sourcing citrus bioflavonoids for dietary supplements, functional foods and beverages


From sourcing to research, development and cutting-edge extraction science, the team at Ingredients by Nature leverages its core expertise to create highly purified ingredients, extracts and concentrates. The company uses its extensive understanding of research to provide unique value-added solutions for customer-specific formula applications. Dr Kevin Robinson spoke to Rob Brewster, President, to find out more

Sourcing citrus bioflavonoids for dietary supplements, functional foods and beverages

Industry acclaimed Brewster Nutrition, along with long-time strategic partner, Syntech International, formed Ingredients by Nature in response to the industry’s need for superior quality ingredients and contract services.

Together, the companies have more than 80 years of combined ingredient manufacturing experience and service to the health food and related industries. “Our quest,” says Rob, “is to preserve, promote and expand the core principles of the natural foods industry while embracing the need for new scientific breakthroughs for nutrient application and absorption.”

Ingredients by Nature provides a range of high quality, customisable, natural specialty food ingredients for the manufacturing chemist, including — amongst others — citrus bioflavonoids.

NBR: What are citrus bioflavonoids?

RB: Bioflavonoids are polyphenolic compounds made from plants and are typically found in certain fruits and vegetables. Some foods, such as chocolate and wine, contain bioflavonoids as well. They are important natural compounds with diverse biologic activities. They are an important part of proper nutrition because they act as potent antioxidants.

Although there are thousands of different kinds of bioflavonoids, this article focuses on citrus bioflavonoids. Citrus bioflavonoids constitute an important series of flavonoids. They are derived naturally from citrus fruits, and they have been shown to act synergistically with vitamin C to neutralise free radicals. The major bioflavonoids found in citrus fruits are diosmin, diosmetin, hesperidin, naringin, naringenin, narirutin, neohesperidin, nobiletin, tangeretin, quercetin, rutin, eriodictyol and eriocitrin.

NBR: What nutrition and health benefits do bioflavonoids provide?

RB: Citrus bioflavonoids have been shown in numerous studies to be potent antioxidants. The antioxidant properties of flavonoids have been recognised for more than 40 years and, by 2016, nearly 23,000 publications have appeared (according to research in the Scopus database).

Increasing our intake of bioflavonoids helps to prevent free radicals from causing harm in the body. The antioxidant and anti-inflammatory benefits of citrus bioflavonoids have been shown to support metabolic, circulatory, cognitive and joint health. Citrus bioflavonoids support balanced immune cell activity for better immune response, and support for respiratory health.

Citrus bioflavonoids have a synergistic function with vitamin C for enhanced immune support, and have also been shown to increase the absorption of vitamin C. They provide metabolic support and help to maintain healthy cholesterol levels.

NBR: What are the best applications for citrus bioflavonoids?

RB: The versatility of citrus bioflavonoids makes them an ideal addition in food, beverage and dietary supplement applications. They can be suspended in liquids and may be used in a variety of beverages. They provide bitter and sour taste notes for specialty beverages, including beer. They also serve as natural preservatives, providing another benefit for food and beverage products.

Citrus bioflavonoids are ideal for applications targeting support for the immune system, respiratory health, cognitive health, vascular integrity, metabolism, cholesterol, joint health and systemic antioxidant support.

Sourcing citrus bioflavonoids for dietary supplements, functional foods and beverages

NBR: What tests and quality standards should manufacturers look for in citrus bioflavonoids?

RB: Brewster Brand Citrus Bioflavonoids are formulated to a total bioflavonoid content by HPLC as well as ORACFN value, measuring specific antioxidant activity against the most influential free radicals that are naturally found in the human body: hydroxyl, peroxyl, peroxynitrite, singlet oxygen and superoxide anion.

They are also examined for NF-kB values. NF-kB plays a key role in regulating and balancing the immune response.

NBR: What research is available regarding citrus bioflavonoids?

RB: A recent study published in Critical Reviews in Food Science and Nutrition demonstrated favourable outcomes for the anti-inflammatory, antioxidant, lipid-lowering and insulin-sensitising properties of the bioflavonoid hesperidin.1

Another study published in Advances in Nutrition looked at the biologic activities of citrus bioflavonoids, particularly on lipid metabolism in obesity, oxidative stress and inflammation in the context of metabolic syndrome. In particular, it showed that the citrus bioflavonoid aringin displayed strong anti-inflammatory and antioxidant activities.2

A study in Mediators of Inflammation suggests that the bioflavonoid hesperidin may have therapeutic effect on allergic asthma. It demonstrated profound inhibitory effects on airway inflammation in a mouse model of asthma.3

NBR: What differentiates the Brewster brand from others?

RB: Beginning in 1950, Brewster pioneered the bioflavonoids category. Brewster Brand Citrus Bioflavonoids have been perfected and offer the broadest spectrum bioflavonoid profile on the market.

Many available bioflavonoids are sourced solely from oranges, but there are many other options. Drawing from a larger selection of citrus provides more opportunity for customisation.

Bioflavonoids sourced from orange, lemon, lime, tangerine and grapefruit provide the broadest bioflavonoid profiles. Each one offers its own unique profile, creating better opportunities for customised formulations.

Another consideration is standardisation. Decades ago, Brewster Nutrition pioneered citrus extract standardisation.

Standardised bioflavonoid ingredients ensure consistency in every batch. Manufactured and distributed by Ingredients by Nature (IBN), Brewster Brand Citrus Bioflavonoids have overcome most formulation hurdles.

IBN manufactures customer-specific formulations, made possible with its wide variety of citrus complexes and purified extracts. Furthermore, IBN helps customers through each step, and can assist with the best applications and forms for finished product delivery systems, such as high-mesh milling for drink applications as well as citrus bioflavonoid granulations for density adjustment.


1. J.M. Assini, et al., “Citrus Flavonoids and Lipid Metabolism,” Curr. Opin. Lipidol. 24(1), 34–40 (2013).

2. A. Chanet, et al., “Citrus Flavanones: What is Their Role in Cardiovascular Protection?” J. Agric. Food Chem. 60(36), 8809–8822 (2012).

3. S.H. Kim, B.K. Kim and Y.C. Lee, “Antiasthmatic Effects of Hesperidin, a Potential Th2 Cytokine Antagonist in a Mouse Model of Allergic Asthma,” Mediators Inflamm. (4 May 2011): doi: 10.1155/2011/485402.