High hydrostatic pressure in astringent and non-astringent persimmons to obtain fiber-enriched ingredients with improved functionality

This study examined the effects of high hydrostatic pressure (HHP) processing on dietary fiber, cell wall sugars, cell wall-modifying enzymes, and techno-functional properties of astringent and non-astringent persimmon flesh. The fruits were subjected to 200 and 400 MPa for 1, 3, and 6 min, at 25 °C. Dietary fiber and alcohol insoluble residue (AIR) were affected significantly (p ≤ 0.05). Soluble fraction of fiber (SDF) decreased, and AIR content increased up to 46% after application of high pressure. HHP reduced total sugar content of AIRs and promoted changes in the contribution of uronic acids (UA) and glucose, obtaining pectin-enriched materials (from 45 to 61% UA) in astringent persimmons treated by pressure. Pectinmethylesterase (PME) activity increased independently of the astringency level of persimmons (from 1.7- to 2.0-fold), while polygalacturonase (PG) activity was highly dependent on pressure and time conditions of HHP treatments. The application of HHP enhanced techno-functional properties of persimmon AIRs. Great water-absorption (21–31 mL/g AIR) and oil-holding (10–14 mL/g AIR) capacities were obtained for HHP-treated astringent and non-astringent persimmons, respectively, which showed the potential of HHP technology to add value to persimmons.The authors gratefully acknowledge the financial support of Spanish Ministry of Science and Innovation through project AGL2008-04798-C02-01/ALI, and “Agrupación Nacional de Exportación de Cooperativas Citrícolas” (ANECOOP) for providing the persimmon samples. Rodríguez-Garayar is also grateful to Department of Education, Universities and Research of the Basque Government for the FPI fellowship awarded.Peer Reviewe