Effect of addition of tomato pomace as a functional ingredient on chemical and sensory properties of biscuit

This research was carried out at the laboratories of the Department of Food Sciences, Faculty of Agriculture, Damascus University, during the period from 2019 to 2021. The research aimed to study the chemical composition, bioactive compounds, antioxidant activity and color indicators of fresh tomato pomace. Fresh tomato pomace was dried using hot air at a temperature of 40 °C for 24 hours, and then it was ground, and the effect of drying process on chemical composition, bioactive compounds, antioxidant activity and color indicators was studied. The effect of partial replacement of wheat flour with tomato pomace powder in three different percentages (5%, 10% and 15%) on some chemical, sensory and color indicators of biscuits was studied, and the effect of storage process for (6) months on bioactive compounds, antioxidant activity and color parameters was also studied.Fresh tomato pomace content of moisture, ash, fat, protein, fiber and total acidity was (86.86%), (7.28%), (11.13%), (21.81%), (35.93%), (2.44%) respectively, and the content of total phenols was (443.63) mg Gallic/100g, and flavonoids (38.72) mg quercetin/100g (based on dry weight), and the antioxidant activity was (63.64)%.The drying process led to a significant decrease (0.05≥P) on tomato powder content of moisture, pH, total phenols content, antioxidant activity, and color indicators (L and a), While the total acidity was increased, as the moisture content of tomato pomace powder was (14.15)%, the total phenols (248.04) mg Gallic /100g, flavonoids (35.94) mg quercetin/100g (based on dry weight), and antioxidant activity (54.01)%.The results showed that the content of tomato pomace powder of potassium, calcium and magnesium amounted to (23256, 4171.5 and 3022) ppm respectively, the total acidity was (2.73)% as citric acid, and the pH was (4.17).The partial replacement of wheat flour with tomato pomace powder led to a significant increase (0.05≥P) on biscuit contents of moisture, protein, ash, minerals, fiber, total acidity, content of phenols and flavonoids, antioxidant activity, redness (a) and yellowness (b) indices by increasing the level of addition of tomato pomace powder,while pH and brightness indice (L) was decreased. The both of biscuits samples (5%) and (10%) showed the best sensory acceptance compared with other samples.Storage process for 6 months exhibited a significant decrease (0.05 ≥ P) in total phenols content, antioxidant activity, redness (a) and yellowness (b) indices, while total flavonoids content and lightness (L) parameter were not affected