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Monells, Spain

Landl A.,IRTA TA | Abadias M.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Sarraga C.,IRTA TA | Vinas I.,University of Lleida | Picouet P.A.,IRTA TA
Innovative Food Science and Emerging Technologies | Year: 2010

The aim of the present study was the evaluation of the physicochemical, nutritional and microbial quality of acidified Granny Smith (GS) apple purée processed on industrial-scale high pressure system during 3 weeks of refrigerated storage (5 °C ± 1 °C). Two commercially feasible pressure treatments (400 and 600 MPa/5 min/20 °C) and a mild conventional pasteurization at 75 °C/10 min, with pasteurization values of P 70°C7.5 = 8.15 min, were conducted and their effect on total vitamin C (total Vit C), ascorbic acid (AA) and total phenolic content (TPP), and on instrumental quality parameters (color, viscosity, soluble solids, titratable acidity and pH) were comparatively studied. Inactivation of indigenous microorganisms (total aerobic mesophilic and psychrotrophic counts and moulds and yeasts) of the apple product was also studied and monitored during storage. Total Vit C and AA contents were unaffected by the 400 MPa and the mild pasteurization treatment. TPP content was not changed during processing at 400 MPa, but was affected by the 600 MPa and also slightly by the pasteurization treatment. Experimental data on the loss of total Vit C during storage were described with a first-order reaction kinetic and times of half loss between 9.3 to 10.3 days could be estimated for the three studied processes. Storage provoked loss of TPP content and color deterioration of pressurized GS puree samples, which was attributed to enzymatic browning reactions. Microbial counts were reduced by the different preservation techniques below the detection limit (50 cfu g-1) and storage revealed no further growth. Industrial relevance: This is one of the first studies applying commercial industrial-scale high pressure equipment for the pasteurization of an acidified apple purée product. The pressures of 400 and 600 MPa with 5 min holding time at ambient temperature render economically feasible processes with high throughput and productivity. In the European Union the most important fruits in terms of production are apples. Apple purée is a largely consumed preserve in many households and beside apple juice or cider is one of the most important apple products in the market. In contrast to traditional apple purée preparation, high pressure processing or mild thermal treatments could imply new opportunities for the apple processing industry in developing more fresh-like, value-added apple products with reasonable shelf life. © 2010 Elsevier Ltd. Source


Casals C.,IRTA - Institute of Agricultural-Alimentary Research and Technology | Vinas I.,University of Lleida | Landl A.,IRTA TA | Picouet P.,IRTA TA | And 2 more authors.
Postharvest Biology and Technology | Year: 2010

Brown rot caused by Monilinia spp. is a serious postharvest disease affecting stonefruit. Currently, no chemical fungicide is allowed to be applied to stonefruit postharvest in Spain, which creates the need to develop effective postharvest treatments. This is the first report using radiofrequency (RF) heating to control brown rot in peaches and nectarines artificially inoculated with Monilinia fructicola or with natural Monilinia spp. inoculum. From preliminary studies, a RF treatment at 27.12MHz, with 17mm distance between fruit and upper electrode and 18min exposure time was selected as effective conditions to control brown rot in peaches without affecting fruit quality. This RF treatment was investigated to control M. fructicola inoculated 0, 24 and 48h before RF treatment and using inoculum concentrations of 10 3, 10 4 and 10 5conidiamL -1. The average brown rot incidence ranged from 44-82% to 63-100% in 'Summer Rich' and 'Placido' peaches, respectively. Brown rot reduction did not generally depend on the time of inoculation. RF treatment significantly decreased the incidence of brown rot in 'Summer Rich' peaches inoculated at 10 3, 10 4 and 10 5conidiamL -1, whereas in 'Placido' peaches, brown rot was only reduced when fruit were inoculated at 10 3conidiamL -1. The RF treatment was also investigated in naturally infected fruit where the Monilinia spp. development was completely inhibited in both 'Summer Rich' and 'Placido' peaches. No brown rot control was observed in nectarine fruit artificially inoculated or with natural inoculum. © 2010 Elsevier B.V. Source

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