Application of citric acid and mild heat shock to minimally processed sliced radish: Color evaluation
2 Materials and methods
2.1 Plant material and sample preparation
Radishes (Raphanus sativus L.) were purchased from a local market in Mar del Plata, Argentina. They were kept at 5 ± 1 °C in darkness prior to processing. Radish roots were separated from leaves and washed in tap water to eliminate any surface contamination. Then, they were cut with a manual cutter into slices of about 3–4 mm and washed again in tap water using a ratio of sliced radish to water of 1:10 (w:w).
2.2 Treatments application
The samples were divided into 16 lots for the application of the different treatments: immersion in citric acid solutions and thermal treatments as single and double hurdle technologies. Citric acid treatments were carried out by immersion of radish slices in citric acid solutions of 0.3, 0.6 and 0.9% (w/w) (Merck, Argentina) for 1 min. The ratio between solids and the soaking solution was 1:10 (w:w). Thermal treatments were carried out in a thermostatically controlled water bath with recirculation (Lauda E300, Germany). The samples were placed in sterile containers and immersed in water at 50 °C for 1, 2 and 3 min. Thereafter, samples were removed from the bath and cooled immediately in cold water at 0–4 °C for 3 min. For the application of combined treatments (hurdle technology), heat treatment was carried out followed by immersion in citric acid solution. Table 1 summarizes the different treatments applied as single and double hurdle technologies.
Table 1. Applied treatments performed as simple and double hurdle technologies.