Effect of oleaster (Elaeagnus angustifolia) flour on gluten free cake properties

Celiac is an autoimmune digestive disorder caused by the consumption of gluten and the only way of treatment is consuming gluten free diet. Cake fortification due to its high consumption is pursuing by the bakery industry and the application of dietary fibers is increasing due to its relation to human health. In this research, the effect of adding different parts of oleaster (core powder, peel and flesh powder and whole powder) at different concentrations (5, 10 and 20%), on physicochemical and sensory properties of gluten free cakes were investigated. Flour structure, functional properties, unique taste, dietary fiber, minerals and phenolic content of oleaster has made it a good ingredient in bakery products, yoghurt, ice cream, baby foods, chocolate and cookies. Oleaster due to the high content of fiber and minerals could be used in preparing gluten free functional foods. Due to the high demand for gluten free products for celiac patients, our goal was formulation optimization of gluten free cake based on corn flour and oleaster.
 
Corn flour (Tarkhineh, Tehran), sugar (Zarin Alborz), vanilla and baking powder (Bartar Co.), egg (Telavang), sunflower oil (Ladan) and oleaster were purchased from a local shop in Ahvaz. After cleaning and removing impurities of oleasters, peel, flesh and core were separated, grinded and passed through mesh no. 35. Samples were kept in plastic bags at room temperature. Corn flour was partially (5, 10 and 20%) substituted with Powder of core, peel, flesh and whole oleaster. Moisture, pH, fat, protein, fiber, specific volume, textural properties, color and sensory properties of cakes were determined. Data were analyzed using a completely randomized design in SPSS and graphs were plotted using Excel.
 
Low nutritional value and low diversity of gluten free products are major problems for celiac patients. Food scientists are trying to increase the nutritional value of such products through the addition of functional ingredients. Results of the present research showed a significant effect of adding oleaster powder on the physicochemical and sensory properties of free gluten cake samples. By increasing oleaster powder, moisture content of cake samples was increased and the highest moisture content was seen in samples containing peel and flesh powder which is due to presence of hygroscopic constituents like fibers and sugars. The addition of oleaster powders was significantly increased ash of samples which is due to the higher mineral content of oleaster comparing to corn flour. Evaluation of the browning index showed a significant effect of oleaster powder. Crust browning index increased by increasing the powder level in all types of cake samples. The highest browning index was seen in samples containing 20% core powder and the lowest was in the control. The browning index increased because of a rising Maillard reaction due to the higher amount of monosaccharides in oleaster powder. By increasing oleaster powder, firmness of samples increased and the lowest and highest firmness was seen in samples containing peel and flesh and core powder respectively. During storage time, by rising oleaster powder level, firmness increased. A significant increase of firmness was due to decrement of volume and thickening air bubbles walls in cakes crumb. By increasing oleaster powder in cakes, fat and protein content decreased and fiber increased. The lowest fat content was seen in samples containing 20% core powder. Sensory evaluation of cakes approve that oleaster powder could be used as a functional ingredient in cake formulations due to its nutritional and functional properties.