The Functional and Rheological Properties the Mesocarp Layer of the Oleaster (Elaeagnus angustifolia L.) grown in Karaman

Abstract

The oleaster (Elaeagnus angustifolia L.), also known as wild olive, is a small fruit with three parts: the outer peel or exocarp layer, the edible part or mesocarp layer, and the inner seed or endocarp layer. The mesocarp layer is rich in essential vitamins and has great potential for use in various food products. The flour made from the mesocarp layer has a moisture content of 8.99%, an ash content of 2.66%, a fat content of 0.55%, a protein content of 5.99%, a crude fiber content of 3.32%, and a total dietary fiber (TDF) content of 26.36%. The TDF content is divided into insoluble dietary fiber (IDF) and soluble dietary fiber (SDF), which are 21.35% and 5.01%, respectively. The flour has color values of L*: 75.14, a*: 2.86, b*: 23.87, and a water activity value of 0.314. The water solubility, water absorption, and oil absorption are 67.33%, 4.91 g water/g sample, and 2.26 g oil/g sample, respectively. Additionally, the mesocarp layer contains minerals such as Mg, P, K, Ca, Fe, and Na. The mesocarp layer significantly affected the thermomechanical properties of wheat flour. As the substitution level of the mesocarp layer increased from 10 to 30%, the water absorption capacity, dough development time and stability time of the wheat dough significantly decreased. Specifically, the water absorption capacity dropped from 53.5% to 47%, dough development time reduced from 1.10 to 0.75 min, and stability time decreased from 8.90 to 2.25 min. Substituting a mesocarp layer in wheat flour can significantly improve product shelf-life due to slower retrogradation. The mesocarp layer is an functional ingredient in the food industry.