Ph.D. Dissertation:

Optimization of fiber extraction from apple wastes٫ physicochemical properties evaluation of the extracted fiber and its application as a fat replacer in producing low-calorie cake

Replacement of energy compounds with dietary fiber in high-consumption food products can be used to increase the level of public health. The aim of this study was to optimize fiber extraction from apple waste and cake production with reduced fat. Optimization of fiber extraction from apple waste using response level method and Design-Expert software It was done in the form of a box-bin design in which the fixed variables included the extraction method (alcoholic and aqueous), temperature (60-90 ° C) and time (150-50 minutes). Extracted fiber, carbohydrate and moisture content, as well as water holding capacity, oil storage capacity and extraction efficiency were evaluated. In this study, the optimal conditions were water extraction time of 136.86 minutes and temperature of 86 C C. Based on the results, carbohydrates, moisture, oil storage capacity, water storage capacity, fiber content of samples in aqueous and alcoholic extracts were 85.22%, 89.91% - 6.49% and .10.47% - 2.463 (g / g), respectively. ) And 1.749 (g / g) - 2.210 (g / g) and 2.409 (g / g) - 4.774% and 5.196%. Cake production was done by replacing apple fiber obtained from aqueous extraction with ratios of 0, 5 and 10% with cake formulation oil. Optimization of the cake formulation at storage times of zero, 15 and 30 days was performed by the response surface method and the box-box design. The results showed that with increasing the amount of fiber, moisture, fat, firmness and adhesion, the springiness of the cakes increased and the volume decreased. With increasing shelf life, moisture, fat, aw increased and stiffness, stickiness, cake spring decreased. The results of sensory evaluation showed that increasing the amount of apple fiber decreased the overall acceptance of treatments. The cake contained 9.855% of apple fiber and 14.9% of oil, on the thirteenth day of storage, the sample was optimal in terms of characteristics. The results showed that the use of apple pulp in the cake reduced the fat content by 9.3% compared to the control sample. According to the optimization results, the optimum sample moisture content is 25.891%, water activity 0.870, fat 15.384%, specific gravity 81.540 cm3 / g, hardness N 851.7, spring content 0.1820 cm and adhesion 438 / 0 was set. The use of apple fiber in cake formulations as a fat substitute can be a good way to produce new products, enriched with dietary fiber and low in calories. The industrialization of this product requires further studies to .increase the shelf life of this product

Keywords: Keywords: Apple fiber, fat substitute, cake, sensory properties