Avaliação da presença de compostos geradores de amargor e estratégias para sua redução em suco de Ponkan

Abstract

The demand for juices from different citrus species has been growing worldwide due to their sensory aspects and their nutritional properties and bioactive compounds with various health benefits. However, processing citrus juice involves a complex chain of biochemical reactions. The most important of these, if left unchecked, is the formation of bitterness in the juice, which affects its quality, shelf life and acceptability by consumers, generating significant losses for companies. Therefore, this study aimed to evaluate the formation of bitterness in Ponkan mandarin juice and to propose technological strategies for its reduction. The compounds that have an impact on bitterness (limonin and naringin) were evaluated in the different tissues (peel, albedo, seeds) of the fruit and in the juice of the Ponkan, using high-performance liquid chromatography. The results showed the presence of limonin in all the samples, concentrated in the seeds (3413.93 ± 13.05 mg/kg), followed by the peel (285.90 ± 4.58 mg/kg), albedo (253.73 ± 0.23 mg/kg) and juice (13.19 ± 0.25 mg/L). The naringin content in the seeds was lower than the Limit of Detection (LOD), with the highest content found in the albedo (559.73 ± 6.60 mg/kg), followed by the juice (55.86 ± 0.26 mg/L) and peel (322.13 ± 6.30 mg/kg) respectively. The Ponkan juice was treated with different bitterness reduction strategies: [1] physical treatments: centrifugation and pasteurization; [2] chemical treatment: Florisil®; [3] blends with cryoconcentrated tangerine juice and added syrup, both in proportions of 2.5%, 5%, 7.5% and 10% (v/v). The greatest reduction in limonin content was obtained with the Florisil® treatment (75%), however, the treatment of blends with syrup achieved the greatest reduction in naringin (37%) followed by the centrifugation treatment (28%). Pasteurization was the treatment that increased both the limonin (6%) and naringin (7-14%) contents and the treatment of blends with cryoconcentrated tangerine juice increased the naringin content (16%). However, the sensory results of the acceptability test, using a 9-point hedonic scale, indicated that the blends with cryo-concentrated tangerine juice (score: 6.44) showed a higher percentage of acceptability than the blends with syrup (score: 6.11), which showed no statistical difference between the treatments (p<0.05). This means that the best strategy for reducing bitter taste in Ponkan mandarin juice would be to combine treatments such as centrifugation, treatment with Florisil® and blends with tangerine cryoconcentrate.