1,721,175 research outputs found
The role of heat and mass transfer phenomena in atmospheric freeze-drying of foods in fluidised beds
No full textStability of dried pumpkin snacks packed in bio-polymeric films through accelerated shelf-life testing
No full textThis research evaluated the storage characteristics of dried pumpkin packed in two different films: polylactic acid (PLA) and polyethylene (PE) by accelerated shelf-life testing (ASLT) at three storage temperatures: 30, 40, and 50 °C. Weight loss, pH, water activity, color, and total microbial count of the samples were monitored at fixed times during the experiments. After 2 days of storage at 50 °C, the weight loss for the PLA and PE packaging reached its maximum value at 9.15 ± 0.8% and 6.53 ± 1.6%, respectively. The microbiological results demonstrated that, with a total plate count of fewer than 4 log CFU/g, the dried pumpkin samples did not degrade while being stored at different temperatures. Bioactive compound content (total polyphenols, ascorbic acid content, and carotenoid content) and antioxidant activity were determined at the end of storage, and they significantly changed with higher temperatures. The largest total polyphenols losses were observed for samples PLA 40 °C and PLA 50 °C (40%) and samples PE 50 °C (55%). For both packaging under the same storage conditions, antioxidant activity and ascorbic acid concentration likewise showed a similar pattern. The color changes observed during the storage were described by the non-enzymatic browning process using a pseudo-first-order reaction in terms of Chroma. The activation energy in terms of Q10 (defined as the ratio of the rate constants when the temperature is raised by 10 °C) and the storage time at 25 °C were determined. The results showed that PLA film is an appropriate packaging for preserving the physico-chemical properties of dried pumpkin snacks
STUDY OF COOLING BEHAVIOUR OF ADMIXTURES OF EXTRA VIRGIN OLIVE OIL WITH HAZELNUT OIL BY DIFFERENTIAL SCANNING CALORIMETRY
No full textTargeted phenolic profile of radler beers by HPLC-ESI-MS/MS: the added value of hesperidin to beer antioxidants
Full text linkThe well-known health beneficial properties of beer are mainly due to phenolic antioxidants. Citrus-flavored beers represent a growing side-market in the beer industry, sparingly investigated to date. The phenolic profile of commercial radler beers (R1, R2) was investigated to evaluate the impact of the lemon juice added to beer in the industrial production. Results were compared to those obtained for opportunely chosen commercial beer (B) and lemonade (L). The study was carried out by an HPLC-MS/MS with an electrospray ionization source in selected ion recording mode, analyzing in a single chromatographic run 26 compounds belonging to the different phenolic classes of hydroxybenzoic, hydroxycinnamic and caffeoylquinic acids, flavonoids and prenylflavonoids. Different phenolic profiles were found for R1 and R2, mainly ascribed to different malt/hop/recipe used for the beer. High to very high level of hesperidin were found in the radlers, so that a major impact on phenolic antioxidants of the radlers was due to the lemon. Similarly, a major impact of the lemon aromas was found, D-limonene being the dominant peak resulting from the GC-MS analysis of the volatile fraction of the radlers. Graphical Abstract: [Figure not available: see fulltext.]
Development of a diafiltration-pervaporation process for beer dealcoholisation
Full text linkNowadays, worldwide low-alcohol and alcohol-free beer markets are growing rapidly, and this leads to a strong demand of improved technologies for their production. Among the various membrane-based processes, a dialysis in diafiltration mode, with no transmembrane pressure difference, has been chosen as first step of a combined process for beer dealcoholisation which includes a pervaporation stage to recover aroma compounds which are then integrated to the final low-alcohol beer. The results of experimental tests for the optimization of beer diafiltration process using a bench scale unit and two different membranes of cellulose and polyacrylonitrile are shown in this work. A commercial lager beer has been dealcoholized, in a discontinuous diafiltration mode, interweaving concentration and dilution stages, up to an alcohol content lower than 1.2 %vol., which is the residual alcohol content for low alcohol beverages in European countries. Various dialyzing solutions and operating parameters (e.g., temperature, flow rate, volumetric concentration ratio) were tested in order to improve the ethanol removal from the beer. The physical-chemical characteristics of the beer such as pH, electrical conductivity, density and colour and free-phenolic profile, before and after the dealcoholisation process were evaluated. Results showed no substantial differences between the membranes tested for the dealcoholisation process and small differences in the physical and chemical characteristics of beer before and after the treatment
Caratterizzazione termoanalitica, tramite tecnica DSC, di olii extravergine di oliva trattati con microonde
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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
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