High-power ultrasound pretreatment for efficient extraction of fractions enriched in pectins and antioxidants from discarded carrots (Daucus carota L.)

IDROVO ENCALADA, ALONDRA M.; PÉREZ, CAROLINA D.; CALDERÓN, PAOLA ALZATE; ZUKOWSKI, ENZO; GERSCHENSON, LIA N.; ROJAS, ANA M.; FISSORE, ELIANA N.

JOURNAL OF FOOD ENGINEERING

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2019 vol. 256 p. 28 - 36

0260-8774

A useful pectin-enriched fraction (PEF) extracted through high-power-ultrasound (HPUS) pretreatment and sodium carbonate was efficiently obtained from discarded carrots. Formerly, the effect of HPUS-power intensity and time (A: 40 min-2.08 W/cm2; B-E: 5-20 min 10W/cm2) on carrot powder (CP) used for PEF-isolation, was investigated. Reducing carbohydrates-, cell-wall neutral sugars- (NS), uronic acids- (UA) of pectins, and protein releases increased with HPUS-energy. CP had antioxidant capacity, containing - and -carotene, lutein, -tocopherol. Only HPUS B-E treatments (10W/cm2) were capable to produce matrix disruption, promoting polymers? release. CP pretreated through selected E-treatment (20 min; 10W/cm2) followed by 0.1M-Na2CO3 (1 h-stirring) extracted the whole pectin content of CP (UA=14.0%). PEFs were orange, with co-extracted antioxidants. More substituted (1.27 NS/UA ratio) three lower molecular weights? components of HPUS-PEF produced higher Newtonian viscosity before shear-thinning, and calcium-crosslinked gels with lower elastic modulus (G?=12Pa). Sustainable HPUS/Na2CO3 method isolated efficiently an antioxidants-carrying PEF useful as functional food additive.