INVESTIGADORES
SALVATORI daniela marisol
congresos y reuniones científicas
Título:
Effects of maturity stage and use of drying on seet cherries (Napolitana var.)
Autor/es:
PIRONE, B.; DEL CASTILLO, M. ; DE MICHELIS, A.; DANIELA M. SALVATORI
Lugar:
Mar del Plata
Reunión:
Congreso; Interim Meeting of the International Color and Food; 2010
Institución organizadora:
Grupo Argentino del Color y International Color Association
Resumen:
 This work compares the effect of pre-drying treatments and convective drying on cherry color of different mature degree. The following pretreatments were used: 1) B: blanching with saturated steam (1.5 min) at atmospheric pressure and cooling in cold water (2 min at 4 °C) in order to diminish enzymatic browning, and 2) combined treatments: a) B + dipping in 10 % citric acid (w/v) during 5 min (Dip1) and b) B + Dip 1 + dipping in 2.5% calcium lactate (w/v) during 5 min (Dip 2). These combinations were studied in order to evaluate the possibility of protection of anthocyanic pigments throughout the drying process by the incorporation of acid and to preserve product texture by means of calcium adding in mature as well as in immature fruits. Chemical composition of fresh fruit was determined in order to study color degradation as a function of mature degree and process. Drying of cherries, with and without pretreatment, was performed at 70 °C, 4 m/s air velocity and 10% RH. Weight loss (WL), colorimetric coordinates (HunterLab color space) and pigments (extracted and measured by spectrophotometric reading at 530 nm) were evaluated throughout drying (Ochoa et al, 2001). Soluble solids concentration (SSC) was higher in mature fruits, but titratable acidity (TA) levels were similar. Mature cherries had almost full dark red skin color, while immature ones had full light yellow-pink skin color. During drying, fruits without pretreatments presented an important WL and a red color decrease (L and a parameters diminished in relation to initial values) from bright red color, more or less intense according to mature grade, to brown. Blanched fruits, of both stages, appeared discolorated and luminosity increased. During drying, lack of color maintained from the beginning of the process; red color disappeared and fruits exhibited an intense yellow color, this being due to variations in the structural form of anthocyanins. At the end of the process luminosity decreased in all cases, but in a lesser extent for immature fruits. A red color enhancement was observed in mature cherries as a consequence of acid concentration that positively influenced pigments expression. Because of a lower initial concentration of pigments, immature fruits did not exhibit the same behavior that matures ones. The combined treatment was more effective for stabilization of pigments and texture (preliminary evaluated).  The fruits at lower pH did not showed browning during dehydration compared with fruits without acid treatment. The greater values observed in mature fruits would indicate that high initial sugar concentration enhances color stability. Moreover, concentration of fruit compounds due to drying process could have contributed to protection of red color.