Using pistachio peel powder and melon seed flour to enrich the Functional-low-fat mayonnaise sauce and evaluation its rheological properties

With the increasing the global population and the scarcity of food resources, using agricultural waste has become a recent challenge for food scientists. 

In this study, to optimize the amount of crop residues and the preparation and formulation of dietary and beneficial sauce, two crop residues, pistachio peel, and melon seed, were used as flour. In this study, treatments of mayonnaise sauce were formulated using pistachio peel powder with 0, 0.1, 0.5, 0.75, and melon seed flour with 6, 12, 18, 24, 30, and 36%. Mayonnaise treatments were evaluated at time intervals of the production day, 30th day, 60th day, 90th day for pH, moisture content, ash (%), fat (%), carbohydrate (%), protein (%), colorimetric indices (Lightness, redness, yellowness), viscosity, total microbial population, stability test, and particle size. For the sensory evaluation, the 5-point hedonic test was performed by ten trained panelists scoring these components (color, taste, texture, fluctuation, consistency, general acceptance). Statistical analysis was performed using Minitab 17 software at the statistical level of 0.05. 

The results showed that moisture content, carbohydrate, ash, protein, pH, viscosity, and particle size were increased by increasing pistachio peel powder and melon seed flour. Total microbial population and the stability of mayonnaise treatments were significantly decreased (p≤0.05). Also, by increasing storage time, moisture content and the stability of mayonnaise and particle size were increased. Rheological indices such as cohesion decreased, and firmness and adhesion indices were increased (p≤0.05). All sensory scores of mayonnaise treatments decreased during storage time, and finally, treatment coded T1(0.1% replacement of pistachio green peel powder and 6% melon seed flour) was selected as optimal, and T6 with 0.75% replacement of pistachio green peel powder and 36% melon seed flour) as worst sample. The use of pistachio peel powder and melon seed flour significantly reduced the microbial population of mayonnaise treatments. Higher values than the optimum treatment cannot be used due to decrease in the stability and increase in the microbial population, as well as reduction of sensory scores.