- ItemOpen AccessApplication of an innovative water-assisted ultraviolet C light technology for the inactivation of microorganisms in tomato processing industries(Elsevier, 2021) Abadias i Sero, Mª Isabel; Colás Medà, Pilar; Viñas Almenar, Inmaculada; Bobo, Gloria; Aguiló-Aguayo, IngridWe aimed to study the efficacy of a water-assisted UVC light device (WUVC) as an innovative clean technology for the disinfection of fresh sound tomatoes and processing wash water and water turbidity was evaluated as a critical parameter. First, wash waters with different turbidities (from 0.4 to 828 NTU) were inoculated with Listeria innocua and treated in the WUVC device at different dosages. Secondly, fresh tomatoes, inoculated with L. innocua and non-inoculated ones, were treated using the WUVC device containing wash water of different turbidities for different times. The reduction of L. innocua populations on wash water and on the surface of tomato was influenced by turbidity; lower reduction values were observed at higher turbidities. Washing tomatoes with tap water with UVC lamps off (control treatment, TW) decreased L. innocua population on the surface of tomatoes but did not eliminate those bacteria that went into the water. Contrarily, when UVC lights were on, L. innocua population in wash water after treatment significantly decreased, those in clean water being the lowest populations. Reductions of native microbiota on the clean water treated with the highest UV-C radiation dose were lower than those obtained when tomatoes were artificially inoculated. We demonstrated that high reductions of L. innocua population on fresh tomatoes could be achieved using the WUVC system but some drawbacks related to the increase of turbidity should be solved for its implementation in real conditions.
- ItemOpen AccessAre fruit surface differences in two blueberry cultivars major drivers of contrasting postharvest dynamics?(MDPI, 2022) Moggia, Clàudia; Lara, Isabel; Graell Sarlé, Jordi; Schmeda-Hirschmann, Guillermo; Thomas-Valdés, Samanta; Lobos, Gustavo A.Fresh blueberries are prone to softening and dehydration during postharvest, which limits their competitiveness when reaching the final markets. Commercial cultivars ‘Duke’ and ‘Brigitta’ exhibit contrasting softening patterns. Although ‘Duke’ berries usually show higher firmness levels at harvest as compared to ‘Brigitta’, they display higher softening and weight loss rates after cold storage. The aim of this study was to evaluate the physicochemical changes and modifications in cuticle composition of ‘Duke’ and ‘Brigitta’ blueberries across five developmental stages: green (G), 25 and 50% pink (25P, 50P), and 75 and 100% blue (75B, 100B), to determine those characters with the most influence on their postharvest behavior. For each developmental stage, maturity parameters, respiration, and ethylene production rates were assessed, and cuticular wax and cutin were analyzed. Principal component analysis (PCA) revealed that ‘Duke’ berries were characterized by higher respiration and ethylene production rates, while ‘Brigitta’ showed higher contents of oleanolic acid and α-amyrin over total waxes. The results suggest that larger surface/volume ratios and higher amounts of ursolic acid and lupeol in ripe fruit may underlie higher weight and firmness loss rates of ‘Duke’ berries as compared to ‘Brigitta’
- ItemOpen AccessUnravelling the contribution of the Penicillium expansum PeSte12 transcription factor to virulence during apple fruit infection(Elsevier, 2018) Sánchez-Torres, Paloma; Vilanova, Laura; Ballester, Ana-Rosa; López-Pérez, M.; Teixidó i Espasa, Neus; Viñas Almenar, Inmaculada; Usall i Rodié, Josep; González-Candelas, Luis; Torres Sanchis, RosarioBlue mould disease caused by Penicillium expansum infection is one of the most important diseases of pome fruit accounting for important economic losses. In the present study, the PeSte12 transcription factor gene was identified, and deletant mutants were produced by gene replacement. Knockout mutants showed a significant decrease of virulence during apple fruit infection. Virulence was affected by the maturity stage of the fruit (immature, mature and over-mature), and disease severity was notably reduced when the apples were stored at 0 °C. The ΔPeSte12 mutants resulted defective in asexual reproduction, producing less conidia, but this characteristic did not correlate with differences in microscopic morphology. In addition, the ΔPeSte12 mutants produced higher quantity of hydrogen peroxide than the wild type strain. Gene expression analysis revealed that PeSte12 was induced over time during apple infection compared to axenic growth, particularly from 2 dpi, reinforcing its role in virulence. Analysis of transcriptional abundance of several genes in ΔPeSte12 mutants showed that in most of the evaluated genes, PeSte12 seemed to act as a negative regulator during axenic growth, as most of them exhibited an increasing expression pattern along the time period evaluated. The highest expression values corresponded to detoxification, ATPase activity, protein folding and basic metabolism. Gene expression analysis during apple infection showed that 3 out of 9 analysed genes were up regulated; thus, PeSte12 seemed to exert a positive control to particular type of aldolase. These results demonstrate the PeSte12 transcription factor could play an important role in P. expansum's virulence and asexual reproduction.
- ItemOpen AccessEvaluation of Pseudomonas graminis CPA-7 as a biopreservation method for fresh-cut pear: Physicochemical, enzymatic, and nutritional quality(SAGE Publications, 2018) Zudaire Villanueva, Lorena; Viñas Almenar, Inmaculada; Iglesias Valenzuela, María Belén; Plaza, Lucía; Abadias i Sero, Mª Isabel; Aguiló-Aguayo, IngridBiological preservation methods with bacterial antagonists have emerged as alternatives to chemical sanitizers for extending shelf-life and reducing the population of pathogenic microorganisms. In addition, calcium plays an important role in maintaining the quality of fruit, and postharvest calcium treatments might determine the potential of fruit for processing. The objective of this work was to evaluate the effect of the postharvest application of calcium and biopreservation with the CPA-7 strain of Pseudomonas graminis on the quality parameters of fresh-cut pears. After harvest, whole pears were dipped in calcium chloride solution (1%, w/v) or water (control) for 10 min at 25 ℃ and stored for five months at temperatures ranging from 0 to −0.5 ℃. Both batches of fruit were minimally processed and dipped in a solution containing CPA-7 and an antioxidant solution or kept untreated, and both groups were stored at 4 ℃ for six days. The postharvest calcium treatment had no remarkable effect on the quality of the whole and fresh-cut pears. The enzymatic activities (PPO, PME and PG) related to browning and softening were constant in fresh-cut pears after storage, and the application of P. graminis CPA-7 had a positive effect on the activity of PPO. Finally, a combined effect of the biocontrol agent and calcium treatment was not demonstrated.
- ItemOpen AccessEffect of pre-harvest conditions and postharvest storage time on the quality of whole and fresh-cut calçots (Allium cepa L.)(Elsevier, 2019-01-23) Zudaire Villanueva, Lorena; Viñas Almenar, Inmaculada; Simó Cruanyes, Joan; Sans, Silvia; Abadias i Sero, Mª Isabel; Aguiló-Aguayo, IngridPre-harvest conditions such as cultivar, cultivation site and planting time could affect the storability, quality and shelf-life of fruit and vegetables. The influence of onion cultivar, cultivation site and planting time on the storability and quality of whole fresh and roasted calçots (Allium cepa L.) was investigated. Moreover, the suitability for fresh-cut processing of four different calçots was studied. Samples from 'Montferri' onion cultivar presented the best storability. Overall, postharvest storage time had no remarkable effect on the quality of whole calçots but produced an increase on the antioxidant properties of all samples. In relation to the aptitude to minimal processing, 'Montferri' onion cultivar cultivated at Viladecans in August showed the best results in terms of quality throughout their postharvest storage time. Therefore, cultivar and postharvest storage time could have more effect than cultivation site and planting time on the quality of whole and fresh-cut calçots.