Valorization of citrus residue for the development of phytochemical enriched candy: textural, bioactive, molecular, and structural characterization

The citrus residue (peel and juice sac residue) is a waste generated by the fruit processing industries and every year a large amount of citrus residue is globally produced. Thus, a process for the valorization of citrus residues has been developed aiming to formulate a candy with zero waste process. In this study, two types of citrus peel candies with and without juice sac residue (CPR and CP, respectively) were prepared. Additionally, this study provides the effect of blanching time (0, 4, and 8 min) and sweeteners (sucrose and sucralose) on the quality characteristics of candies. The quantitative/qualitative analysis revealed the presence of different compounds such as calcium (60.84–85.43 mg/kg), potassium (469.07–519.75 mg/kg), sodium (7.43–16.07 mg/kg), iron (0.98–2.78 mg/kg), magnesium (32.08–43.98 mg/kg), phosphorus (31.87–41.50 mg/kg), total phenols (404.34–571.79 mg/100 g), and flavonoids (198.44–220.33 mg/100 g), along with high antioxidant (50.30–64.49 µmol/100 g) and antidiabetic (19.66–32.82%) activity of citrus residues-based candies. The ranking analysis showed that blanching time had a significant ( p ≤ 0.05) effect on all the parameters than the sweeteners. The maximum retention of bioactive compounds was observed in candies blanched for 4 min. The overall acceptability was higher for the sucralose-based candies compared to sucrose-based candies irrespective of blanching time. Thus, the sucralose-based CPR and CP candies blanched for 4 min were selected owing to lower water activity, TSS, hardness, and total sugars with high retention of bioactive compounds and high acceptability. Therefore, this study provides two different applications: the development of fruit-based novel confectionery product along with waste management. Graphical abstract