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Background. Osmotic dehydration (OD) is a technology that allows the concentration mainly of fruits and vegetables, without change of phase, through partial water removal, when immersed in a hypertonic solution of sugar, salt or others. It can be successfully applied to some products whose production is not fully marketed in fresh form. However, an additional process is necessary to stabilize the product. The process leads to the achievement of high quality alternative products, with an extended shelf-life, economy in storage and transport. The aim of this work was to study, at a pilot scale, the behaviour evaluation of a sucrose dehydration solution, during twelve OD reuses, and the quality of processed mandarins. Material and methods. The process was carried out using mandarins (Citrus reticulata Blanco) cv Clementina Nova, from Algarve, Portugal, manually peeled and segments chemically skinned. In assays a 60°Brix sucrose solution was used, conducted in thermo-stabilized baths, at 45°C, 16 h, 40 oscillations per minute and a fruit:solution ratio of 1:2 (m/m). After each OD cycle, the solution was filtered and reconcentred to 60°Brix by sucrose addition, and adjusted to original volume. The osmodehydrated mandarins were stabilized by pasteurization. The drying solution behaviour and mandarins‟ quality were assessed through different physical, chemical and microbiological analysis. Results. The factorial discriminate analysis allowed to distinguish a different behaviour between the original and final dehydration sucrose solution during OD processes, but did not affect its desiccant power, only a high pollutant load development explained by BOD5 values. The results of osmodehydrated mandarins showed that stability was achieved by “combined process” with pasteurization. Conclusions. The results lead to conclude that osmotic dehydration process is a good op-tion to improve mandarin‟s stabilization, after pasteurization, increasing added value. Its viability is connected to the management of the drying solution and the number of uses depends on the type of product being dehydrated and their processing sequence. Though the negative microbial load, it must be given attention to dilute the solution before its release as effluent
Background. Modified atmosphere packaging (MAP) is an important technology to extend mushrooms shelf-life, with maintenance the characterisation as “fresh product”, since allows reducing losses and maintaining quality, once they belong to highly perishable commodities. The aim of this study was to evaluate the potential storage conditions on the properties of fresh cultivated mushrooms - Pleurotus ostreatus when placed in polyethylene trays heatsealed with different polymeric films, passive modification mode, at 4°C. Material and methods. The process was carried out using fresh mushrooms of the first flush, produced under controlled conditions. Investigations were conducted for 11 days. The mushrooms shelf-life was assessed through quality parameters, namely physiological, physicochemical, microbial and sensorial analysis. The marketability was assessed by visual appearance and sensory characteristics change, namely, softening and off-odours and off-flavours development. Results. The factorial discriminate analysis allowed observing the influence of the different polymeric films permeability on the mushrooms storage. On the second day, similar mushrooms behaviour, with all film packages, was observed. From the seventh to the eleventh day, the packages showed an identical storage state, two to two, just the ninth day. This behaviour is related with O2 levels (A and B films) and with CO2 levels (C and D films). Conclusions. The results leads to conclude that PE 65S Cryovac (C) and PD 961 Cryovac (D) films, improve storage mushrooms preservation with good stability during 11 days, showing the beneficial effect of MAP conditions. It is a valuable starting point in order to design a commercial application of modified atmosphere packaging technology with these products
There is a general trend towards a continuous increase in fresh market sales of mushrooms and many methods have been researched to improve quality and shelf life during storage and marketing. As it is known, mushrooms are a very perishable commodity, with very high respiration rate and rapid quality deterioration, when kept at ambient temperature. In order to study the effect of modified atmosphere packaging (MAP) on the quality of three species of oyster mushrooms, P. ostreatus, P. sajor-caju and P. eryngii, whole mushrooms were packaged with two polymeric low density polyethylene films – Vileda Freshmate (A) and PE 52 LV Amcor (B), with passive modified atmosphere and stored at 4ºC. The quality and stability of MA packaged mushrooms were assessed, during storage, by package atmosphere composition (O2, CO2), soluble solid contents, weight loss, texture, surface colour and exudates measurements. It was verified that on the seventh day the P. ostreatus and P. sajor-caju carpophores presented identical quality, when packaged with the two films types, thereafter some decay was observed. Carpophores of P. eryngii had the same quality in the two film types at the end of the established storage
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