Assessment of different debittering techniques to valorize orange peel

Different strategies to reduce bitterness of orange peels were assessed in the present research: (a) blanching in 2% NaCl-water (SALT), (b) blanching in 1% Na2CO3-water (ALK), (c) blanching in water and fermentation with Lactiplantibacillus plantarum (FR), and (d) blanching in water and sugar coating (SUC). Samples were freeze-dried and characterised: total flavonoid and polyphenol contents, volatile composition, and instrumental texture were analysed. A consumer panel assessed samples' acceptance, bitterness perception, and further applications of the developed ingredients. Results showed significant differences in total flavonoid and polyphenol contents, being the SALT and SUC the samples the ones with the highest polyphenol, and the ALK and SUC samples the ones with highest flavonoid content. Bitterness perception seemed to be related to Total Phenolic Content, although influenced by other properties of the samples (e.g., volatile composition). Volatile composition was slightly different among samples but seemed to have an impact on flavour perception. Texture analyses results showed that SALT was the hardest and ALK sample the softest one. SUC and FR samples were the most liked ones, although were perceived as moderately bitter. Further research is needed to better understand bitter perception of processed orange peels to develop highly accepted products.

Automated summary

Different strategies were evaluated to reduce bitterness of orange peels, including blanching in salt or alkaline solution, fermentation, and sugar coating. Analysis of the samples revealed variations in flavonoid and polyphenol contents, volatile composition, and texture. The consumer panel found that samples treated with sugar coating or fermentation were the most liked, although they were still perceived as moderately bitter. Further research is necessary to understand the bitterness perception of processed orange peels and develop highly accepted products.