Chlorogenic Acid Oxidation and Its Reaction with Sunflower Proteins to Form Green‐Colored Complexes

Abstract

Sunflower seeds are used to produce oil for human consumption, but its protein meal by-product has long been used as animal feed. Formation of green-colored complexes through oxidized chlorogenic acid(CGA)-protein interactions is a primary reason why defatted sunflower protein has not been widely utilized by the food industry. Sunflower protein possesses many properties that make it an appealing alternative protein source from both a marketing and formulation perspective, including its low cost, absence of major allergens, low antitrypsin inhibitors, and its status as both vegan and "clean" label friendly. With the global demand for sunflower oil and novel protein sources expected to increase and waste recovery a concern for many, providing uses for the sunflower meal and its fiber and polyphenol components would provide added value to by-products from sunflower oil processing. This review addresses the unique green pigmentation associated with the interaction of sunflower protein and oxidized CGA by outlining the sunflower oil and protein meal market, CGA reactions contributing to greening, methods for CGA extraction, and the effect of processing on sunflower protein quality and the greening reaction. This review also addresses potential food applications of sunflower protein-based ingredients, such as addition of texturized protein to food products; a microencapsulation matrix for antioxidants; edible, flexible biodegradable films; and even use of sunflower butter as an alternative to peanut butter where the green color is not considered undesirable. Continued studies are needed to make sunflower-based products and CGA-extraction processes available across the global marketplace.

Release of phenolic acids from sunflower and rapeseed meals using different carboxylic esters hydrolases from Aspergillus niger

“…Unfortunately, no CA was recovered (Table 2) from either NI-SFM or I-SFM despite the mild alkaline treatment used. Indeed, the high chemical reactivity of CA make it prone to autoxidation at high pH due to its catechol function that rapidly reacts with NaOH and oxidizes in the presence of reactive oxygen species (Wildermuth et al, 2016). Thus, as alkaline hydrolysis was not suitable for assessing the total potentially releasable CA from SFM, all calculations and comparisons between various enzymatic hydrolysis conditions were made on the basis of TCAD content after methanolic extraction, expressed as µmol CAE/g DDM, and…”

Covalent Bonding of Chlorogenic Acid Induces Structural Modifications on Sunflower Proteins

“…It is important to mention that pure sunflower proteins exhibit valuable functional properties (solubility, interfacial activity) . However, when covalently complexed with CGA they become insoluble, indigestible and appear with a green color which hampers their potential applications as food or drug ingredient . Nonetheless, CGA is also a biofunctional compound for food and drug applications .…”

“…[13] However,w hen covalently complexed with CGA they becomei nsoluble,i ndigestible and appear with ag reen color which hampers their potential applications as food or drug ingredient. [14][15][16] Nonetheless, CGA is also abiofunctional compound for food and drug applications. [17,18] Therefore current valorizationp rocedures are often aimed at obtaining the proteins and/or CGA in ap ure form whichd id not find industrial applications, [19] since, duet o their high reactivity formation of complexesb etween the two is hardly avoidable.…”

Lowering greening of cookies made from sunflower butter using acidic ingredients and effect on reducing capacity, tryptophan and protein oxidation

“…The CGA dimer then oxidizes to form highly reactive o-quinones which can subsequently react with amino acids in an aqueous, alkaline environment to form green trihydroxy benzacridine (TBA) derivatives (Liang & Were, 2018a, 2018b. The rate of greening increases with pH and heat, which can limit the application of sunflower butter in bakery applications (Wildermuth, Young, & Were, 2016). Lowering greening is thus paramount if sunflower butter is to be commercialized or adopted by consumers for baking applications where greening is unwanted.…”