Extraction of flaxseed and Plantago Psyllium mucilage: Investigation of rheological properties and efficiency as a fat substitute for the production of low‐calorie cookies.

The purpose of this study was to extract flaxseed mucilage (FM) and Plantago Psyllium mucilage (PM) and to investigate the rheological properties and the substitutability of FM and PM instead of butter in the production of low‐calorie cookies. Therefore, the D‐optimal design was evaluated to investigate the effect of FM and PM replacement at 0%–60% levels on the physicochemical, textural, and sensory properties of the cookie. The results of rheological properties indicated pseudoplastic behavior of FM, PM, and butter. Also, according to the results, PM was stronger than FM and maintained its structure more during rheological tests. The results showed that by increasing the replacement of FM and PM, the moisture content and water activity of the samples increased significantly (p < 0.05) whereas no noticeable changes were observed at 6 and 10 days after cooking (p > 0.05). Antioxidant capacity increased with increased FM replacement. Also, a* increased significantly with increased PM replacement percentage. The firmness and penetration energy of cookies decreased while L* increased with increased replacement of FM and PM. Overall acceptance of sensory evaluation also increased with the replacement of FM and PM. Hence the highest sensory score was related to samples with 30% FM together with 30% PM. A comparison between optimal and control samples showed that the amount of protein, fat, and peroxide in the control sample was higher than in the optimized cookies. In general, replacing butter with FM and PM in the cookie formulation to produce new products with low‐calorie content is possible and it is easy to reduce the relatively high amount of fat in the cookie composition without significant decreases in the product quality. Practical applications: Today, the tendency to use low‐fat foods is very strong among consumers. Consumers are significantly concerned about the health risks of a high‐fat diet and are trying to reduce the amount of fat in their diet. Flaxseed mucilage (FM) and Plantago Psyllium mucilage (PM) have the capacity to hydrate, develop viscosity, and maintain freshness, particularly in bakery products. In this study, FM and PM were extracted and were used as fat substitutes in the preparation of low‐calorie cookies. The physicochemical, textural, and sensory properties of the cookie were studied. According to the results, well‐acceptable low‐calorie and low‐fat cookies could be prepared by substituting 20% FM +20% PM instead of 40% butter in terms of physicochemical properties and sensory evaluation. [ABSTRACT FROM AUTHOR]