Utilization of food industry by-products and wastes for improving functional properties of bread and pasta

In the first stage of the study; various physical and chemical properties (color, moisture, ash, protein, fat, carbohydrate, energy, free acidity, water and fat holding capacity, emulsion capacity) of 14 different by-products (apple, artichoke, watermelon, melon, lemon, banana, pomegranate, eggplant, orange, garlic, onion and grape) produced as waste in the food industry were determined. Additionally 4 different doses (0, 5, 10 and 15 %) of these by-products were applied to wheat flour and the rheological properties of the dough (farinograph and extensograph) were investigated. Bread and pasta production were carried out by using 3 different doses (0, 5 and 10 %) of 5 different by-products (apple, watermelon, orange, grape and banana) which were found superior as a result of rheological analysis. Various physical, chemical, technological and functional properties of the produced bread and pasta samples were determined. The highest ash content among raw materials was determined in banana by-products (17.95 % dw); the highest protein content was observed in watermelon by-products (18.16 % dw), and the highest carbohydrate content was determined in apple by-products (83.31 % dw). It has been determined that the water and oil holding capacities of all by-products were higher than wheat flour and semolina. The water absorbtion capacity of the doughs increased with the addition of by-product and the highest water absorbtion capacity (76.81 %) was observed at the 15% replacement rate. Dough development times was prolonged as the substitution rate increased. Dough stability time differed according to by-products, and the highest grape by-product additions (10.40 min) and 10 % substitution rate (7.99 min) were observed. According to the extensograms of the dough at the 135th minute, the highest resistance was in apple (824.63 BU) and watermelon (842.38 BU) by-products powder added samples; the greatest extensibility was in banana (119.63 mm) and artichoke (121.25 mm) by-products powder added samples and the highest energy was obtained in banana (100.13 cm2) and apple (91.13 cm2) by-products powder added samples. It was determined that the resistance and energy values of the doughs decreased as the substitution ratio increased. Among the 5 raw materials used in the production of bread and pasta production, the highest total dietary fiber (58.44 %), phenolic compound (8927.35 mg GAE/kg) and antioxidant activity(3483.50 mg TE/kg) values were seen in grape by-products. Among the raw materials, the highest phytic acid content was determined in wheat semolina (326.31 mg/100g), while the lowest was determined in apple and watermelon by-products. The highest calcium (444.02 mg/100g) and potassium (7850.21 mg/100g) content among the raw materials were measured in banana by-products, the highest iron in apple by-products (23.02 mg/100g), the highest magnesium in watermelon by-products (265.64 mg/100g), and the highest zinc (1.35 mg/100g) and phosphorus (368.70 mg/100g) in wheat semolina. Among the bread samples produced by adding food industry by-products, the highest brightness values were measured with the addition of apple by-products; the highest a* and b* values were obtained with the addition of orange by-products. Breads with added watermelon by-products provided the highest specific volume and crust thickness values; and the lowest hardness and chewiness values of all bread samples. It was determined that as the substitution rate of by-products increased, the specific volume values of the samples decreased, and the hardness and chewiness values increased. While the addition of grape pulp increased the springiness values of the bread samples, the springiness values of all by-products decreased as the substitution rate increased. With the increase in the substitution rate of food industry by-products, an increase in moisture, ash and fat values, a decrease in carbohydrate and energy values were determined, and no change was observed in protein values of breads (p>0.05). It was observed that as the substitution rate of by-products added to the bread samples increased, the nutritional fiber, total phenolic content and antioxidant activity values of the samples increased, while the phytic acid contents of the samples decreased. In terms of mineral substance content, it was determined that the banana by-products added breads were superior to the other samples and the 10% substitution rate provided the highest values. When the pasta samples were examined in terms of color values, the highest L* b* and SI values were obtained in the orange by-products added samples, and the lowest in the banana by-products added samples. The highest firmness value was observed in the grape by-products added pasta samples, and it was determined that there was no significant difference between the other by-products added samples (p>0.05). Among the pasta samples, the highest weight loss was observed in watermelon and orange by-products added samples (p>0.05). The highest protein, fat, carbohydrate and energy values for pasta samples were determined in samples with added watermelon by-products. The increase in the by-product rate of food industry by-products added to the pasta samples led to an increase in dietary fiber, total phenolic substance content and antioxidant activity values, and a decrease in phytic acid content in pasta samples. While the highest calcium, potassium and zinc content were detected in banana-utilised pasta samples, and the highest magnesium and phosphorus contents were determined in samples with added watermelon by-products containing pasta samples.