Preventing chlorogenic acid quinone-induced greening in sunflower cookies by chlorogenic acid esterase and thiol-based dough conditioners

Sunflower seeds contain a high concentration of chlorogenic acid (CGA), which reacts with amino acids to form green pigments under alkaline conditions during food processing. Here, we present two approaches to prevent green pigment formation in sunflower cookies by (A) Addition of free thiols from cysteine and glutathione to sunflower cookie dough and (B) hydrolyzing CGA into caffeic acid and quinic acid with a CGA esterase from Lactobacillus helveticus. Greening occurred more slowly with cysteine; however, neither cysteine nor glutathione prevented greening in the cookies during storage. Chlorogenic acid esterase hydrolyzed CGA in both sunflower butter and flour, resulting in the complete elimination of greening in the sunflower cookies. CGA esterase treatment was efficient as the enzyme could be applied in low amounts (<100 ppm) directly to the dough without needing to pretreat either sunflower butter or flour. Overall, our data indicate that CGA esterase treatment was an effective method of eliminating unwanted greening in sunflower cookies made with baking soda. Long term, these results may represent a method of increasing the use of sunflower butter and flour in high pH baking applications by enabling their use in neutrally colored baked products such as cookies and muffins.

Automated summary

Two methods were presented to prevent greening in sunflower cookies: adding free thiols from cysteine and glutathione, and hydrolyzing chlorogenic acid (CGA) into caffeic acid and quinic acid using a CGA esterase. Cysteine had a slower reaction, and neither cysteine nor glutathione prevented greening during storage. CGA esterase effectively eliminated greening by hydrolyzing CGA in sunflower butter and flour. The enzyme could be directly applied to the dough, making the process efficient and allowing the use of sunflower butter and flour in neutrally colored baked products.