Flaxseed: Phenolic Rich Superfood

Nutritionists have been intrigued by the potential health benefits offered by flaxseed (Linum usitatissimum L.). This versatile seed is a rich source of diverse phenolics, encompassing lignans, phenolic acids, flavonoids, phenylpropanoids, and tannins.

The inclusion of flaxseed in both food and food products has been consistently on the rise, fueled by its elevated levels of essential omega-3 fatty acid alpha-linolenic acid (ALA), dietary fiber, and natural phenolic antioxidants.

Antioxidants, whether synthetic or natural, possess the capability to postpone specific forms of cell damage and neutralize reactive radical species formed during oxidative reactions in metabolism. Primarily consisting of phenols, polyphenols, carotenoids, thocyanins, and tocopherols, antioxidants play a pivotal role as phytochemicals in plants.

Due to their safety, consumers tend to prefer natural antioxidants, such as those found in flaxseed, which have been linked to a reduced risk of cancer development.

A significant portion of the phenolic acids present in flaxseed, including p-hydroxybenzoic, trans-ferulic, and trans-p-coumaric acids, exists in an ester-bound state. Noteworthy is the accumulation of ferulic and p-coumaric acid glucosides in substantial concentrations within flaxseed. Additionally, phenolic acids like caffeic acid and their glucosides have been detected in flaxseed.

Caffeic acid, classified as a hydroxycinnamic acid, is widespread in plants and serves as a crucial intermediate in lignin biosynthesis, a fundamental component of woody plant biomass.

Flavonoids, a subgroup of polyphenols featuring a C6-C3-C6 structure comprising two aromatic rings connected by a three-carbon linkage, include diverse categories such as anthocyanins, flavanols, flavones, flavanones, and flavonols.

The flavonoid content in flaxseed, ranging from 0.3 to 0.71 g per kg of flaxseed, is contingent upon growth conditions and cultivar types. In flaxseed, flavonoids predominantly exist in glucoside forms, such as herbacetin 3, 8-O-diglucopyranoside, herbacetin 3, 7 O-dimethyl ether, and kaempferol 3, 7-O-diglucopyranoside.
Flaxseed: Phenolic Rich Superfood

Notes: Republished article

Flaxseed: Rich source of ω-3 fatty acid

Flaxseed (Linum usitatissimum L.) is species of the family Lineceae (flax family), which means “very useful”. Flax was first introduced in United States by colonists, primarily to produce fiber for clothing.

Flaxseed is the richest plant source of the ω-3 fatty acid i.e. α-linolenic acid (ALA) Flaxseed oil is low in saturated fatty acids (9 %), moderate in monosaturated fatty acids (18 %), and rich in polyunsaturated fatty acid (73 %). Of all lipids in flaxseed oil, α- linolenic acid is the major fatty acid ranging from 39.00 to 60.42 % followed by oleic, linoleic, palmitic and stearic acids.

Flaxseed oil is enjoying an upsurge in popularity as a result of reports on its benefits to human health and its potential to reduce the risk of certain diseases. Flaxseed oil, fibers and flax lignans have potential health benefits such as in reduction of cardiovascular disease, atherosclerosis, diabetes, cancer, arthritis, osteoporosis, autoimmune and neurological disorders.

ALA is beneficial for infant brain development, reducing blood lipids and cardiovascular diseases. Flaxseed proteins are relatively high in arginine, aspartic acid and glutamic acid whereas lysine, methionine and cystine are limiting amino acid.
Flaxseed: Rich source of ω-3 fatty acid

Antioxidants in flaxseed

Flaxseed (Linum usitatissimum L.) has been the focus of interest of nutritionists due to potential health benefits.

Flaxseed is a rich source of different types of phenolics such as lignans, phenolic acids, flavonoids, phenylpropanoids and tannins.

Day by day, incorporation of flaxseed in food and in food products has been increasing due to its high content of essential omega-3 fatty acid, alpha-linolenic acid (ALA), dietary fiber and natural phenolic antioxidants

Antioxidants are synthetic or natural compounds that can delay some types of cell damage and quench reactive radical species formed during oxidative reactions in metabolism. They include mainly phenols, polyphenols, carotenoids, thocyanins and tocopherols, which main groups of phytochemicals found in plants.

Natural antioxidants have been associated with cancer development are generally opted by consumers because of their safety.

Most of the flaxseed phenolic acids such as p-hydroxybenzoic, trans-ferulic and trans-p-coumaric acids are ester bound. Among these phenolic acids, ferulic and p-coumaric acid glucosides were accumulated at high concentrations in the flaxseed. In addition, phenolic acid like caffeic acid and their glucosides were also reported in the flaxseed.

Caffeic acid is an organic compound that is classified as a hydroxycinnamic acid. It is found in all plants because it is a key intermediate in the biosynthesis of lignin, one of the principal components of woody plant biomass and its residues.

Flavonoids are the polyphenols, with C6-C3-C6 skeleton that consists of two aromatic rings joined by a three-carbon link. Flavonoids generally include anthocyanins, flavanols, flavones, flavanones and flavonols.

Depending upon growing and cultivar conditions, flaxseed possesses about 0.3-0.71 g of total flavonoids per kg of flaxseed. In the flaxseed, flavonoids are in the form of their glucoside such as herbacetin 3, 8-Odiglucopynanoside, herbacetin 3, 7 O-dimethyl ether, and kaempferol 3, 7-O-diglucopyranoside.

Antioxidants in flaxseed

Flaxseed nutritional compounds

Flaxseed is mainly considered as oilseed crop. It has been used in various forms such as flour, oil and seed. The whole flaxseed is flat and oval with pointed tips, varies in color from dark to yellow, and measures approximately 2.5 × 5.0× 1.5 mm. Flaxseed contains a seed coat or true hull(also called testa), a thin endosperm, two embryos, and an embryoaxis.

Flaxseed continues to surge forward in its recognition as a functional food, being rich in the essential omega-3 fatty acid, alpha linolenic acid and many phytochemicals. Flaxseed also provides dietary fiber and protein (flax primer) an was singled out as one of six neutraceuticals.

Flaxseed has emerged as a potential functional food being good source of α -linolenic acid (ALA), unsaturated fatty acids (linolenic acid, linoleic acid, oleic acid), soluble flaxseed fiber mucilage (d-Xylose, L-Galactose, LRhamnose, d-galacturonic acid), lignans (secoisolariciresinol diglycoside (SDG)), monoglycerides, triglycerides, free sterols, sterol esters, hydrocarbons (protein), balast, phenylpropane derivatives.

Flaxseed also contains monounsaturated fatty acids (MUFAs), such as oleic acid. ALA and linoleic acid are both essential fatty acids (EFA), meaning they cannot be synthesized by the human body and must be derived from the diet.

ALA is beneficial for infant brain development, reducing blood lipids and cardiovascular diseases. Flaxseed proteins are relatively high in arginine, aspartic acid and glutamic acid whereas lysine, methionine and cystine are limiting amino acid. Flaxseed dietary fiber exhibits positive effect to reduce constipation, to keep better bowel movement and as hypocholestermic agent.

Flaxseed is the richest source of plant lignans, which are phytoestrogens and serves as precursors in the production of mammalian lignans. SDG is the predominant lignan in flaxseed with minor amount of pinoresinol and matairesinol. It was suggested that lignans may act to prevent oxygen radical production, thus effectively reducing atherosclerosis. It also may have anticancer property. At some extent, SDG helps in bone development.

Flaxseed nutritional compounds