| 1. |
- Alessandrini, Laura, et al.
(författare)
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Effect of steam cooking on the residual enzymatic activity of potatoes cv. Agria
- 2011
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 91:12, s. 2140-2145
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of this work was to study the influence of steam cooking on pectin methylesterase (PME) and endogenous alpha- and beta-amylase activities in different tissues (cortex and pith) of raw and heat-treated potatoes cv. Agria. Three different cooking temperatures were chosen (55, 70 and 85 degrees C). For each cooking trial, time-temperature profiles were recorded and the degree of cooking was expressed in terms of cooking factor. RESULTS: Steam cooking contributed to significantly activate PME at 55 degrees C and to reduce its activity at the final processing temperature (85 degrees C), with the highest amount in the cortex (0.3745 +/- 0.0007 mu mol galacturonic acid (GA) g(-1) fresh weight (FW) min(-1)) compared with the pith (0.2617 +/- 0.0012 mu mol GA g(-1) FW min(-1)). The presence of heat-labile and heat-stable isoforms of PME in the considered potato tissues was also assumed. Heat treatment by steam resulted in a significant decrease in endogenous alpha- and beta-amylase activities in both tissues compared with the raw potato, though without complete deactivation. Starch-degrading enzymes were also found to be differently distributed in the raw tuber. CONCLUSION: Steam cooking affected in different ways the assessed residual enzymatic activity in the considered tissues of potatoes cv. Agria. Further research is needed to confirm the results obtained. (C) 2011 Society of Chemical Industry
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| 2. |
- Capelli, Filippo, et al.
(författare)
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Decontamination of food packages from SARS-COV-2 RNA with a cold plasma-assisted system
- 2021
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- The accidental contamination of food and food packaging surfaces with SARS-CoV-2 is of increasing concern among scientists and consumers, particularly in relation to fresh foods that are consumed without further cooking. The use of chemical sanitizers is often not suitable for these kinds of commodities; therefore, a non-thermal sanitation technology could help to increase safety in relation to the food supply chain. Cold plasma has proven to be a promising strategy for virus inactivation. This research is aimed at evaluating the ability of a cold plasma sanitation system to inactivate SARS-CoV-2 RNA on packaged foods. Two different plastic materials were investigated and subjected to 5- and 10-min exposure to plasma after experimental inoculum of the RNA. In addition to viral degradation, possible changes in the performance of the materials were evaluated. Shelf-life of the foods, after exposure of the packages to plasma, was also investigated. Results showed that 10 min of exposure was sufficient to almost completely eliminate the viral RNA from package surfaces. The treatment did not produce any significant variation in packaging material performance or the shelf-life of the tested packaged products, indicating the potentiality of this treatment for the decontamination of packaged products.
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| 3. |
- Demir, Eda, et al.
(författare)
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Reversible electroporation caused by pulsed electric field – Opportunities and challenges for the food sector
- 2023
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Ingår i: Trends in Food Science and Technology. - 0924-2244. ; 139
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Forskningsöversikt (refereegranskat)abstract
- Background: The application of Pulsed Electric Field (PEF) to food may result in reversible or irreversible electroporation of cell membranes, depending on whether cell homeostasis is restored after resealing. Restoration of homeostasis upon reversible electroporation implies the recovery of the pre-pulse transmembrane potential and the restoration of cell metabolic functions. Enhanced membrane permeability caused by reversible electroporation would allow impregnation of cells with foreign molecules and/or stress-induced metabolic reactions. The impregnation of cells and the induction of stress in cells could open new opportunities for the application of PEF in the food industry. Scope and approach: Most of the published literature on the application of PEF in food systems focuses on the irreversible process, mainly targeting cold pasteurization or mass/heat transfer enhancement. This review focuses on the application of reversible electroporation to enhance metabolic production of secondary metabolites, to accelerate seed germination and fermentation, and as pre-treatment prior to freezing and drying. Finally, the challenges for industrial application of this technology are discussed. Key findings and conclusions: The application of reversible electroporation as a pre-treatment prior to unit operations in the food industry has the potential to improve the quality of the final product in terms of structure, nutritional value or increased productivity. However, its industrial application faces several challenges, related to difficulties in process optimization, scale-up and equipment design. Therefore, significant efforts are still required to apply reversible electroporation on an industrial scale in the future.
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| 4. |
- Panarese, Valentina, et al.
(författare)
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Microscopic studies providing insight into the mechanisms of mass transfer in vacuum impregnation
- 2013
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Ingår i: Innovative Food Science & Emerging Technologies. - : Elsevier BV. - 1466-8564. ; 18, s. 169-176
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Tidskriftsartikel (refereegranskat)abstract
- A microscopic method was developed to detect pressure thresholds for gas outflow and solution impregnation during vacuum impregnation of plant materials. Raw materials with different porosities (apple and spinach) were impregnated with an isotonic sucrose solution at a minimum pressure of 150 mbar. An automatic vacuum controller system (AVCS) was used to control the pressure during vacuum impregnation. Micrographs of tissues subjected to vacuum impregnation were recorded as the pressure in the treatment chamber was varied. Image analysis allowed the evaluation of the pressure at which gas was released from the pores (seen as bubbles) during the application of vacuum, and the pressure at which tissue impregnation took place during the restoration of atmospheric pressure. Spinach tissues showed gas release at a much lower pressure than apple, and impregnation commenced at a much higher pressure. These differences in pressure threshold could be caused by the narrow pores in spinach and possibly by changes in leaf volume. Industrial relevance: Vacuum impregnation is considered a promising technology to facilitate the impregnation of vegetable tissues with different solutions containing, e.g., firming, antioxidant or antimicrobial agents. The mass transfer taking place during vacuum impregnation depends on the characteristics of the tissue pores. Effective vacuum impregnation requires the efficient removal of air from the tissue during vacuum treatment to obtain complete filling of the tissue during the subsequent impregnation step. The findings of this study may allow food manufacturers to optimize vacuum impregnation parameters depending on the porosity characteristics of the raw material. (C) 2013 Elsevier Ltd. All rights reserved.
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| 5. |
- Panarese, Valentina, et al.
(författare)
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Vacuum impregnation modulates the metabolic activity of spinach leaves
- 2014
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Ingår i: Innovative Food Science & Emerging Technologies. - : Elsevier BV. - 1466-8564. ; 26, s. 286-293
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Tidskriftsartikel (refereegranskat)abstract
- In this study calorimetric measurements provided evidence of a drastic increase of spinach leaf gross metabolism as a consequence of vacuum impregnation (VI) at a minimum pressure of 150 mbar with trehalose and sucrose isotonic solutions. When applying VI extracellular air is replaced by the impregnation solution, potentially limiting tissue respiration to any remaining air volume in the tissue. However the observation that impregnated leaves showed photosynthetic activity suggests that not all air was exhausted during VI. Hence impregnation appears to reach a maximum with remaining gas filled compartments. Metabolic inhibitors impregnated together with sugars showed that the short-term metabolic response, causing the drastic increase of gross metabolism upon VI, depends on mitochondrial oxygen consuming pathways. The metabolic effect following mannitol impregnation was comparable with water impregnation, suggesting that the strong metabolic effect reported here is only seen for molecules that can be metabolized and provide energy to the cells. Industrial relevance: Vacuum impregnation is used to incorporate additives in fruit and vegetable tissues, such as anti-browning agents, microbial preservatives or cryoprotectants. As a promising technology in the food industry, deeper insights on the metabolic consequences of vacuum impregnation are required to define and control the shelf-life of the processed fruits and vegetables. (C) 2014 Elsevier Ltd. All rights reserved.
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| 6. |
- Rocculi, Pietro, et al.
(författare)
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Effect of minimal processing on physiology and quality of fresh-cut potatoes, a review
- 2009
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Ingår i: Food. - 1749-7140. ; 3, s. 18-30
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Tidskriftsartikel (refereegranskat)abstract
- Fresh-cut fruit and vegetable are minimally processed products that have to maintain their quality (appearance, texture, flavour and nutritive value) similar to those of the fresh product. The fundamental principle underlying the quality of these commodities is that they are metabolic active tissues and, as a consequence, show physiological response to preparation procedures as well as to the environment created in the package in which they are enclosed. Minimal processing for fresh-cut potato production includes raw material selection, washing, peeling and cutting, pre-treatments, drying, weighing and packaging. The purpose of this review is to analyse the effects of the different minimal processing steps on the physiology and related quality of fresh-cut potatoes. Particular attention is given to the newest studies on processing innovation and innovative scientific approaches for a better understanding of fresh-cut products as biological systems. In this direction the use of ozone sanitization, natural dipping pre-treatments and/or coatings (e.g. edible film enriched in ascorbic and citric acid), and modified atmosphere packaging at high O 2 levels result the most promising and non-invasive techniques for the preservation of fresh-cut potatoes. As far as physiological studies of the product are concerned, fundamental metabolic research for process optimisation and quality assurance is needed. For this aim isothermal calorimetry may provide a versatile tool to conduct fundamental metabolic studies of the effect of different processing steps on the quality and shelf-life of fresh-cut potatoes.
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| 7. |
- Rocculi, Pietro, et al.
(författare)
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Effects of the application of anti-browning substances on the metabolic activity and sugar composition of fresh-cut potatoes
- 2007
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Ingår i: Postharvest Biology and Technology. - : Elsevier BV. - 0925-5214. ; 43:1, s. 151-157
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Tidskriftsartikel (refereegranskat)abstract
- We investigated possible physiological effects of the application of anti-browning substances on metabolically active potato tissues. The use of citric acid, ascorbic acid and L-cysteine for browning prevention of fresh-cut potatoes increased their metabolic heat production as measured by isothermal calorimetry. This effect was particularly high after treatment with L-cysteine, which also proved to be the most effective substance for inhibiting enzymatic browning. This increase in metabolic activity was concentration dependent and correlated with a decrease in the concentration of reducing sugars in the tissue, showing evidence that substances used in the prevention of enzymatic browning may have physiological effects in the tissue. The possible implications of these effects for the fresh-cut industry are discussed.
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| 8. |
- Tylewicz, Urszula, et al.
(författare)
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Gas in Scattering Media Absorption Spectroscopy (GASMAS) Detected Persistent Vacuum in Apple Tissue After Vacuum Impregnation
- 2012
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Ingår i: Food Biophysics. - : Springer Science and Business Media LLC. - 1557-1866 .- 1557-1858. ; 7:1, s. 28-34
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure and the capillary pressure of the pore space are important variables for better understanding of the complex phenomena occurring during vacuum impregnation (VI) of plant tissues. In this study, we used GASMAS (Gas in Scattering Media Absorption Spectroscopy) of oxygen to, non-destructively, measure the dynamics of the internal pressure in apple pieces after restoration of the atmospheric pressure. Apple pieces were impregnated with isotonic sucrose solution (18% w/v) at different reduced pressures (15, 30, 45 kPa (abs.)). After restoration of the atmospheric pressure, the pressure of the remaining pore space gas could remain as low as 50 kPa (abs) and rise slowly toward ambient over a time scale of hours. Both the residual vacuum and the timescale of pressure equilibration with ambient varied with applied vacuum level and apple variety. It is proposed that at least a part of the pore space of apples may be hydrophobic, giving rise to a negative Laplace pressure, and thus the convective flow of impregnating solution is arrested at a mechanical equilibrium where internal pressure is lower than external pressure. Further pressure equilibration can then only be achieved either by gas diffusion in gas phase, or by gradual wetting of the pores.
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| 9. |
- Wadsö, Lars, et al.
(författare)
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Isothermal calorimetry approach to evaluate the effect of tissue wounding on vegetable metabolism
- 2005
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Ingår i: Proceedings of the 5th International Postharvest Symposium, Vols 1-3. - 0567-7572. ; :682, s. 1977-1982
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Konferensbidrag (refereegranskat)abstract
- We have made a study by isothermal calorimetry of the heat production response of root and tuber tissue to wounding. Samples with different surface to volume ratios were prepared from carrots, potatoes and swedes (rutabaga) and the overall metabolic heat was measured in closed glass ampoules in a TAM Air isothermal calorimeter. The evaluation was made by assuming that a certain heat production rate per volume tissue was associated with the normal metabolic activity, and that another heat production rate per surface area was associated with the wound response. The results showed that the wound response part was high; in some cases almost half the heat came from the wound response and not from the ordinary metabolic activity. Measurements such as the ones shown here can be used to understand the effect of wound-induced metabolism in produce quality changes and packaging design.
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