Posharvest quality of strawberry as affected by individual and combined mild thermal treatments and pulsed UV light

CONTIGIANI, EUNICE; JARAMILLO-SANCHEZ, GABRIELA; ALZAMORA, STELLA M.; GÓMEZ, PAULA

Wuxi

Encuentro; 2018 Global Food Science Student Competition; 2018

Jiangnan University

Fungal development limits storage life of strawberries leading to great economical losses. Thus, there is a need for postharvest preservation strategies alternative to synthetic fungicides. This work investigated the effect of pulsed light (PL) and mild thermal (TT) treatments, applied as single factors orin combination, on fungal spoilage, mechanical properties, bioactive compound contents and antioxidant capacity of strawberries stored at refrigeration temperatures. Strawberries cv Albion were exposed to PL irradiation for 10 s (Xenon RS-3000B Steripulse-XL, 200-1100 nm, fluence: 11.9 J.cm-2) and/or immersed into sterile water at 46 ± 1 ºC under stirring for 2.5 or 5 min. Combination sequence was TT followed by PL irradiation. Treated fruit were compared against untreated ones throughout 12 days of storage at 5 ± 1 ºC. Data were analyzed by two-way ANOVA andMANOVA. The presence of macroscopic fungal growth was daily visually inspected and results were expressed as percentage of decayed fruit. Puncture test as well as anthocyanin content (pH differential method), phenolic content (Folin-Ciocalteu method) and antioxidant capacity (ABTS·+ assay) determinations were made after processing and throughout the storage. Combined treatments resultedmore effective in preventing fungal decay than individual PL one but the most effective was individual TT of 5 min (2.5 % of infected fruit at day 8). TT of 5 min and its combination with PL improved themechanical properties; but in those samples significant reductions in phenolics (~ 9.5 %) and anthocyanin contents (~ 19.8 %) were observed after 8 days of storage. However, TT of 5 min, unlike the combined treatments, did not show a significant reduction in TEAC values in relation to untreatedfruit. These results showed that TT of 5 min is the most effective method to extend postharvest life of strawberry among the strategies evaluated.