Optimizing the utilization of pomelo (Citrus maxima (Brum.) Merr.) seeds as a quality dietary fiber

Orange seeds, often overlooked as waste, have hidden potential since fiber derived from them contains numerous biochemical substances that can enhance the nutritional value of food. We aimed to investigate the impact of pomelo seed fiber on the biscuit dough’s properties (starch and gluten), physicochemical characteristics, and biochemistry, as well as the product’s shelf life. We studied three types of samples: control (no dietary fiber), biscuits with dietary fiber from pomelo (Citrus maxima (Brum.) Merr.) seeds, and biscuits with wheat germ fiber. Scanning electron microscopy was employed to analyze rubbery starch and gluten in the dough, while response surface methods were used to optimize the biscuits’ strength via a central composite design. The product’s shelf life was determined based on microbial contamination levels. ANOVA test and Tukey’s Honestly Significant Difference post hoc test were performed to assess the differences in physicochemical and biochemical properties. Citrus seed fiber influenced rubbery starch and gluten properties, causing significant differences (p < 0.05) in fracturability, total dietary fiber, and Trolox equivalent antioxidant capacity among the three samples. The biscuits enriched with citrus seed fiber contained flavonoid compounds and acylserotonin, with acyl-Nω-methylserotonin dominating in the C22 and C24 homologs. Despite varied evaluations in texture and aroma, the biscuits with citrus seed fiber were well-received for their taste and boasted an extended shelf life (> 12 months). Dietary fiber obtained from C. maxima seeds not only enhanced the nutritional value of the biscuits but also paved the way for innovative healthy food opportunities.