Sensorial quality of spinach leaves disinfected by an optimized citric acid treatment.

JAGUS, R.J.; FINTEN, G.; AGÜERO, M.V.

Córdoba

Congreso; VI Congreso Internacional de Ciencia y Tecnología de Alimentos (CICYTAC 2016); 2016

Córdoba : Ministerio de Ciencia y Tecnología de la provincia de Córdoba

Leafy greens are constantly demanding feasible technologies and optimized preservation methods to minimize safety risks in minimally processed vegetables. In previous studies we optimized a washing and disinfection step for spinach leaves (Spinacia oleracea L.) with respect to its effectiveness on target microbial populations and pathogen surrogates. However, purchase decision of fresh vegetables is affected by color as it impacts directly on consumer visual perception, and by overall sensorial quality as it determines consumer intention to continue buying a specific product. Therefore, the aim of this research was to determine whether or not the optimized treatment with citric acid 0.5% (CA) can replace the traditional disinfection treatment (SH), sodium hypochlorite 200 ppm (pH 6.5-7.0), with regard to its impact on sensorial quality and instrumental color. Selected leaves were dip-washed 1:20 (w:v) for 2.5 min, centrifuged for 30 s in a salad spinner, and packed in 10 g units (experimental unit) using polyolefin PD960 (Cryovac®, Duncan, USA). Samples were stored under refrigeration (6.5 ± 1 °C) for 14 days. Sensory analysis were carried out by a trained panel (4 members) who evaluated fresh-odor, off-odor, color, texture and general acceptability using a 5-point hedonic scale; with 3 as the acceptability threshold for each attribute, and 5 as the rating which indicates the best quality. Instrumental color was measured using a colorimeter (Minolta CM508b, Japan); chroma (C*), hue angle (Hº) and color difference (ΔE) were calculated for evaluating color changes along with the CIELab parameters a*, b*, and L*. Data were analyzed using the R software, 3.2.2 version, and the significance level for all the statistical procedures was 5%. Results indicated that there were not significant interactions between factors treatment and time; additionally, the effect of treatment was not significant either. Thus, the sensorial impact of CA and SH treatments on spinach leaves did not differ. On the other hand, factor time did affect the responses as it was expected due to leaves senescence. Sensorial attributes? scores decreased along refrigerated storage but even in the last sampling point they were above the acceptability threshold. With regard to color, an increase in L* and a reduction in H° over refrigerated storage was interpreted as leaves turning from green to a lighter green. No significant differences for C* were found and ΔE remained below 5.0, indicating no remarkable differences. Finally, instrumental color correlated well with color judge by the trained panel. Hence, a single-step washing with citric acid did not adversely affect sensorial quality, thus representing a feasible alternative for disinfecting spinach leaves.