Effect of washing-disinfection conditions on total anthocyanins retention and color of fresh-cut strawberries

VAN DE VELDE, FRANCO; PIROVANI, MARIA ÉLIDA; GÜEMES, DANIEL RAÚL; PIAGENTINI, ANDREA

Mar del Plata, Prov. de Buenos Aires

Congreso; AIC 2010 Interim Meeting. Color and Food: from the farm to the table.; 2010

International Color Association (Association Internationale de la Couleur, AIC)

Strawberries are good source of vitamin C and anthocyanins (Cordenunsi et al. 2005). Anthocyanins are the most important pigments of the vascular plants. They are responsible for their appealing and bright red color (Ngo et al. 2007). Another significant property is their antioxidant activity, which plays a vital role in the prevention of neuronal and cardiovascular illnesses, cancer and diabetes (Catañeda-Ovando et al. 2009). There has been an increasing demand for fresh-cut fruits and vegetables, mainly because of their convenience as ready-to-eat products as well as for the health benefits associated with their consumption (Gil et al. 2006). Disinfection of fresh-cut products by washing is an essential operation to eliminate foreign matter and cellular fluids produced by cutting (Pirovani et al. 2004). The aim of this work was to evaluate the total anthocyanins retention and color changes of fresh-cut strawberries after peracetic acid disinfection at different times and temperatures. Response surface methodology was used to investigate the washing of fresh-cut strawberries (Fragaria x ananasa cv. Camarosa) and a Box-Benhken three-level, three-factor design was adopted. The factors and levels investigated were peracetic acid concentration (0, 50 and 100 ppm), time (10, 65 and 120 s) and temperature (4, 22 and 40°C). Responses studied were total anthocyanins retention and color. Total anthocyanins content was determined in the untreated and processed fruits according with Heo and Lee (2005), and the results was expressed in milligrams of pelargodin 3-glucoside per 100 g of fresh weight (mgP3G/100fw). Color (CIE L* a* b* values) was measured with a Minolta spectrophotometer CM-508d/8, D65/10°, SCE. Chroma (C*), hue angle (h) and total color difference (deltaE*) were also calculated. Total anthocyanins content of the untreated strawberries were 24,8 mgP3G/100fw. The response surface model described the experimental data adequately (R2=0,912), exhibiting no significant lack of fit (p≥0,05). The peracetic acid concentration and the processing time, as described by a linear term, and the temperature, as described by the interaction term of time-temperature are significant (p≤0,05) for the total anthocyanins retention model. All the other terms were no significant. The anthocyanins retention decreased as both peracetic acid concentration and time increased. Instrumental color evaluation was affected by process only in L* and a* values. The response surface model described the experimental data adequately (R2=0,73 for L* and 0,79 for a*), exhibiting no significant lack of fit (p≥0,05). Peracetic acid concentration, described by a linear and cuadratic term, was significant (p≤0,05), for L* and a* values respectively. a* was significant affected by temperature too, described by cuadratic term. a* values decreased as both peracetic acid concentration and temperature increased and L* values decreased as peracetic acid concentration increased. The predictive models obtained were shown to be adequate and could be used as a way of improving the washing operation.