Extraction and characterization of grapefruit wall material (Citrus paradise) and its impact on organoleptic properties of bread

Abstract The utilization of fruit by-products in bakery products has gained increasing attention due to their nutritional and functional potential. This study investigated the nutritional composition, and functional properties of grapefruit wall material and to evaluate its impact on bread quality. In the first phase the nutritional composition (including moisture, ash, protein, fat, fiber and total carbohydrates) of grapefruit peel powder was determined following the methods given in AACC. Then, in the second phase wall material was extracted using the alkali extraction method and characterized for the determination of structure through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the flavonoid and phenolic content were quantified, and antioxidant activity was evaluated through DPPH and FRAP. In the last phase, bread was prepared using different concentrations of wall material (T0, T1, T2 = 0 g, 2 g, and 4 g) to evaluate its effects on texture, color, and sensory attributes. Initially, chemical composition of grapefruit peels revealed 76% moisture, 0.81% ash, 6.04% crude fat, 2.56% crude protein, 6.96% crude fiber, and 8.17% nitrogen-free extract. The results showed that increased wall material reduced hardness and chewiness but enhanced cohesiveness, springiness, and adhesiveness after two days of storage. Higher GFWM concentrations also decreased L* values, resulting in darker bread color. Bread prepared with the treatment (T2) achieved the highest sensory acceptability. The incorporation of GFWM enhanced the nutritional and textural qualities of bread, showing its potential as a functional ingredient in cereal-based formulations.