1,721,141 research outputs found
The forgotten method? Pulsed electric field thresholds from the perspective of texture analysis
Full text linkPulsed electric field (PEF) technology has found applications in various industrial food sectors, including the potato industry, winemaking, biorefinery, and juice extraction, among others. The practical implementation of PEF technology in the food industry is however still hindered by several challenges. The detection and quantification of PEF effects are complex due to the variable characteristics and properties of raw materials, including cellular composition, structural organization, textural properties, and tissue porosity. Moreover, the PEF treatment parameters (e.g., pulse amplitude, duration, shape, rate), and process parameters (e.g., temperature, pH, medium conductivity) further complicate the optimization of PEF protocols, requiring a case-by-case approach. Knowledge of treated material properties and their functional dependence on PEF is a crucial prerequisite to informed, intelligent design of treatment protocols. We present an experimental study designed to gain insights into the mechanism behind the changes in textural properties induced by PEF in both plant and animal tissues. These changes in texture are then compared with findings from our previous study on electrical impedance, to highlight how different methods of detection of PEF-induced changes in tissue can yield vastly different results based on the method of analysis used depending on tissue properties. Furthermore, texture analysis unveiled the less-explored effects of PEF treatment on electroosmosis phenomena in both plant and animal tissues. We provide a comparative analysis between plant and animal tissues to elucidate the differences in deformation resulting from PEF treatment. We thus demonstrate how important it is, be it in the development phase or for process control during industrial operation, to choose an appropriate method of characterising PEF-induced changes in tissue to avoid under- or overtreatment
New insights into the glass transition of dried fruits and vegetables and the effect of pulsed electric field treatment
Full text linkPulsed Electric Field (PEF) pre-treatment has been recently studied to be applied to fresh apple, carrot, and potato tissue as novel food technology to improve the drying performances and the quality of final products. Although the modification induced by PEF and the related reactions have been studied as a function of many parameters and related to several quality aspects, no relationship has been investigated with glass transition temperature (Tg) modification of solid products. This study aims to evaluate the effect of PEF treatment on the Tg of different vegetable tissues. Obtained thermograms revealed the existence of two Tg (TgI, and TgII), the first one mainly dependent from the presence of small molecules, such as sugars, organic acids and small amount of amino acids, while high molecular weight starch, fibers and small amount of proteins are associated to higher temperature values of TgII. PEF treated samples of dried apple, carrot, and potato compared to the untreated ones showed a TgII shift at 0.22 aw to a lower temperature, from 45.12 to 43.37, from 45.15 to 31.04 and from 90.23 to 85.81 °C for apple, carrot and potato respectively. The TgII shift confirmed the mobility raise of the system promoted by PEF treatment, creating a less stable matrix
Response of Pink Lady® apples to postharvest application of 1-methylcyclopropene as a function of applied dose, maturity at harvest, storage time and controlled atmosphere storage
No full textBACKGROUND: 1-Methylcyclopropene (1-MCP) is an inhibitor of ethylene reception used in post-harvest treatments to delay
fruit ripening. Several factors affect the efficacy of 1-MCP treatments. The effect of a post-harvest treatment with 1-MCP on the
qualityofPink Lady® apples as a function of1-MCPdose, storagetimeandmaturity at harvestwas investigated.1-MCPtreatment
was further tested in combination with controlled atmosphere (CA) storage.
RESULTS: 1-MCP limited fruit respiration and softening during storage andwas more effective on partially matured fruits and at
prolonged storage times. The delaying of 1-MCP on the increase of ripening index was greater on matured fruits at prolonged
storage times. Thecombinationof1-MCPandCAtreatmentspositivelyaffected quality indicesofmature apples during6months
of storage and 7 days of commercial life, with 1-MCP being more effective than CA. 1-MCP and CA showed positive combined
effects on firmness and ripening index after 6 months of storage, and on firmness and CO2 production after a further 7 days of
commercial life.
CONCLUSION: By knowing fruitmaturity at harvest and expected storage time it is possible to choose the most suitable 1-MCP
dose tomeet themarket requirements by applying a simple polynomial model
Modelling the mechanical properties and sorption behaviour of pulsed electric fields (PEF) treated carrots and potatoes after air drying for food chain management
Full text linkOne of the major challenges of the food industry is to develop more sustainable processing technologies. To address this change, it is necessary to have more information about available innovative technologies and their effect on different food matrices and processes to ensure efficiency in food chain management. The aim of this research was to increase the understanding of the physical modifications induced by the combination of pulsed electric field (PEF) pre-treatment and further drying in carrot and potato tissues by modelling the sorption isotherms and the textural properties. High coefficient of determination up to 0.980 for GAB and 0.977 for BET were obtained confirming the good ability of both models to describe the sorption isotherm of foodstuff. Either BET and GAB classified carrot in a III type shape and potato in II type shape for sorption isotherm. Mechanical properties for carrot and potato considering all PEF treatment and aw levels were reported and fitted by modified Fermi distribution. High coefficient of determination up to 0.995 confirm the ability of Fermi model to describe mechanical properties in relation to water activity (aw)
Metabolomic studies after high pressure homogenization processed low pulp mandarin juice with trehalose addition. Functional and technological properties
No full textThis work aimed to determine the effect of homogenization pressures (HPH) and addition of trehalose on the functional and technological properties of low pulp mandarin juice (LPJ). A set of experiments was designed, combining a non-targeted metabolomic1H NMR based approach together with suspended pulp and transmittance, hesperidin, vitamin C and antioxidant activity analysis. Suspended pulp increased with HPH and trehalose addition. Flavonoid hesperidin initially decreased with HPH but trehalose addition resulted in less flavonoid degradation during storage, increasing the effect with the HPH. Vitamin C was not affected by trehalose and pressure treatment but more Vitamin C degradation was observed in trehalose samples during storage. Antiradical activity improvement by trehalose was conditioned by homogenization pressures and specific bioactive compounds.1H NMR based approach highlighted the HPH effect on the microbiological aspects of low pulp mandarin juice by the identification of key molecules responsible of the microorganism profile evolution during storage
Combination of PEF and Aureobasidium pullulans treatment on acrylamide mitigation in potato crisps
No full textAccording to the new EU Regulation (2017/2158), which has established new “mitigation measures and benchmark levels for the reduction of acrylamide in foods”, there is the necessity to adapt different process methods in order to reduce the acrylamide formation in deep-fat fried potato-based products, and at the same time to maintain the quality of final products acceptable. Among strategies suggested for the reduction of acrylamide in potato crisps, pulsed electric fields (PEF) represent a promising innovative technology with the potentiality to remove Maillard reaction substrates, such as reducing sugars and free asparagine, in raw potato tissues. Recently, it has been reported that the strain L1 of the yeast Aureobasidium pullulans has the ability to assimilate asparagine in food systems. On the basis of this consideration, the aim of the study was to evaluate the possibility of the reduction of acrylamide content in potato crisps, pre-treating the raw material using a combination of PEF treatment to enhance the extractability of asparagine and a subsequent treatment with aqueous suspension of the aforementioned yeast.
Potato tubers (Solanum tuberosum, var. Lady Claire) were manually peeled and sliced and submitted to PEF pre-treatment using a lab-scale unit delivering rectangular shape pulses. An electric field strength of 1.5 kV/cm and 1000 pulses were used. Consequently, PEF-treated samples were soaked in 250 ml of L1 water suspension (108 cells/ml) for different times at 25 C. A commercial deep-fat fryer was used for the frying tests. Fried potato crisp samples were analysed for moisture, asparagine content, colour, texture, oil uptake and acrylamide content. Results showed a significant reduction of asparagine content and therefore of acrylamide formation after frying. PEF pre-treatment of raw potato slices allowed the cell de- compartmentalisation enhancing the sugars and asparagine availability and so their assimilability from yeasts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The influence of different pre-treatments on the quality and nutritional characteristics in dried undersized yellow Kiwifruit
Full text linkUndersized kiwifruits are considered waste; therefore, there is a need to develop sustainable processing technologies for their valorization, in order to have a positive economic impact on their entire production chain. Therefore, the aim of this study was to apply pulsed electric fields (PEF) combined with osmotic dehydration (OD) and air drying (AD) to develop a novel yellow kiwifruit dried snack with high nutritional functionality. In particular, the effect of the different pre-treatments, PEF (200 V/cm) and/or OD (trehalose at 40%), on the color, bioactive compounds content and antioxidant activity (AA) was evaluated on kiwifruit chips air-dried at three different temperatures (50, 60, 70◦C). The results showed that better color maintenance was observed at the drying temperature of 60◦C. Concerning the bioactive compounds, a good retention in total polyphenols (TP), vitamin C content and AA with the DPPH method was obtained on OD and PEF kiwifruit dried snacks, similar to that of control samples. Instead, the ABTS method showed the best AA in PEF and OD/PEF samples. In general, a shorter drying time in the OD-and PEF-treated samples could contribute to the higher sustainability of the process
Fresh-Cut Eruca Sativa Treated with Plasma Activated Water (PAW): Evaluation of Antioxidant Capacity, Polyphenolic Profile and Redox Status in Caco2 Cells
Full text linkPlasma Activated Water (PAW) has recently emerged as a promising non-chemical and non-thermal technology for the microbial decontamination of food. However, its use as a replacement for conventional disinfection solutions needs further investigation, as the impact of reactive species generated by PAW on nutritional food quality, toxicology, and safety is still unclear. The purpose of this study is to investigate how treatment with PAW affects the health-promoting properties of fresh-cut rocket salad (Eruca sativa). Therefore, the polyphenolic profile and antioxidant activity were evaluated by a combination of UHPLC-MS/MS and in vitro assays. Moreover, the effects of polyphenolic extracts on cell viability and oxidative status in Caco2 cells were assessed. PAW caused a slight reduction in the radical scavenging activity of the amphiphilic fraction over time but produced a positive effect on the total phenolic content, of about 70% in PAW-20, and an increase in the relative percentage (about 44-50%) of glucosinolate. Interestingly, the PAW polyphenol extract did not cause any cytotoxic effect and caused a lower imbalance in the redox status compared to an untreated sample. The obtained results support the use of PAW technology for fresh-cut vegetables to preserve their nutritional properties
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