Functionality of Semolina Pasta Supplemented with Grapefruit Flavedo Byproduct: Effect on Phytochemical, Functional, Textural, Cooking, and Sensorial Quality.

Background: Pasta is consumed worldwide and can be an excellent food matrix for supplementation. Grapefruit (Citrus paradisi) flavedo byproduct is reported to contain considerable amounts of bioactive compounds, which represent a valuable and sustainable source of phenolics. So far, there is limited information available about the utilization of grapefruit flavedo byproducts for supplementation of pasta.

Methods: The present study aimed to investigate the effect of freeze-dried grapefruit flavedo powder (GFP) incorporation at various concentrations (3, 6, 9, and 12%) on the phytochemical, functional, textural, microstructural, and sensory quality of the developed pasta.

Results: Fortification with GFP significantly (P<0.05) enhanced antioxidant activities relative to DPPH and FRAP and increased the total phenolic and flavonoid content from 132.41-211.63 mg GAE/100 g and 73.20-96.83 mg QE/100 g, respectively. Supplementation with GFP significantly (P<0.05) reduced the optimum cooking time of pasta, while cooking loss increased up to 6.32% with 12% GFP incorporation, which was still under the acceptable limits (<8%). The addition of GFP decreased the L* value, while the a* and b* values increased for the pasta. SEM analysis presented that GFP incorporation in pasta affected the structural integrity attributable to the enhanced fiber levels, inducing a weaker matrix, as ascertained by textural profile analysis (TPA) with a decline in hardness attribute with increasing GFP concentration. Sensory analysis divulged overall acceptability scores of 8.4 for the pasta with 6% GFP, while further increments in GFP levels led to decreased sensory scores.

Conclusion: Grapefruit peels are typically discarded as waste, the outer layer of which, i.e., flavedo, could be used to enrich pasta. The present research divulged that pasta supplementation with freeze-dried flavedo powder could provide total phenolic content, flavonoid content, and antioxidant potential without compromising on the technological and sensory quality of pasta. Utilization of this citrus waste as a bioactive food ingredient with promising effects represents a valuable byproduct valorization strategy.