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1.
Food Res Int ; 176: 113869, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38163693

RESUMEN

Pulsed 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.


Asunto(s)
Electricidad , Manipulación de Alimentos , Animales , Conductividad Eléctrica , Manipulación de Alimentos/métodos , Temperatura , Alimentos
2.
Foods ; 12(16)2023 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-37627990

RESUMEN

Fish is a fundamental component of the human diet, and in the near future the proportion of aquatic foods originating from aquaculture production is expected to increase to over 56%. The sustainable growth of the aquaculture sector involves the use of new sustainable raw materials as substitutes for traditional fishmeal and fish oil ingredients, but it is crucial that the substitution maintains the nutritional value of the fish meat. In addition, the preservation of the nutritional value should be a mandatory requirement of new technologies that extend the shelf life of fish. In this context, we evaluated the impact of a newly formulated feed and three preservation treatments (brine, pulsed electric field (PEF), and PEF plus brine) on the fatty acid composition and protein and lipid digestibility of sea bass fillets. In non-digested fillets, although slightly reduced by the newly formulated feed (standard = 2.49 ± 0.14; newly formulated = 2.03 ± 0.10) the n-3/n-6 PUFA ratio indicated good nutritional value. The preservation treatments did not modify the fatty acid content and profile of non-digested fillets. Conversely, protein and lipid digestibility were not affected by the different diets but were significantly reduced by brine, with or without PEF, while PEF alone had no effect. Overall, our results indicated that the newly formulated feed containing 50% less fishmeal is a good compromise between the sustainability and nutritional value of cultivated seabass, and PEF is a promising preservation technology deserving of further study.

3.
Foods ; 12(5)2023 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-36900503

RESUMEN

Honey is a worldwide known and appreciated food product. Its appreciation by consumers is due to both its nutritional properties and the extremely reduced processing. The floral origin, color, aroma and taste are key factors in determining the quality of honey. Nevertheless, rheological properties, as crystallization rate, play a fundamental role in the perceived overall quality. Indeed, crystallized honey is often considered of poor quality by consumers, but a fine-grained or creamy texture is becoming interesting from the producers' side. The purpose of this study was to investigate textural and aromatic properties and consumers' perception and acceptance of two monofloral honeys that were differently crystallized. Liquid and creamy samples were obtained from crystallized samples. Physico-chemical, descriptive and dynamic sensory analysis, as well as consumer and CATA tests, were conducted on the three honey textures. The physico-chemical analysis well-discriminated the crystallization levels and evidenced that, although the honey variety was different, the textural properties of the creamy samples are very similar. Crystallization was shown to affect the honey sensory perceptions: liquid samples were sweeter, but less aromatic. Consumer tests allowed the validation of panel data and confirmed consumers' higher appreciation for liquid and creamy honey.

4.
Antioxidants (Basel) ; 12(2)2023 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-36829965

RESUMEN

Shrimp side streams represent an important natural source of astaxanthin. Optimization of the astaxanthin extraction process from shrimp side streams is of great importance for the valorization of crustacean side streams and the development of astaxanthin-related products. The combined and independent effects of two innovative extraction technologies (pulsed electric fields (PEFs) and accelerated solvent extraction (ASE)) alone and/or combined in a sequential step, using two different solvents on astaxanthin extraction from two shrimp species, were evaluated. Astaxanthin content in the extracts of shrimp side streams was determined by both spectrophotometric and HPLC assays, being the determination of the carotenoid profiles performed by HPLC analysis. Compared to a solvent extraction control procedure, the astaxanthin content was increased after ASE and PEF treatments, for both shrimp species, independently of the solvent used. The highest recovery (585.90 µg/g) was obtained for the species A. antennatus, with the solvent DMSO when PEF and ASE were combined, while the increase in antioxidant capacity varied depending on the solvent used. HPLC analysis of the samples revealed the presence of unesterified (all-E) astaxanthin, four unesterified Z isomers of astaxanthin and many unresolved astaxanthin esters. Both technologies are useful tools to recover antioxidant valuable carotenoids such as astaxanthin from shrimp side streams.

5.
Nutrients ; 14(24)2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36558496

RESUMEN

Plasma 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.


Asunto(s)
Antioxidantes , Brassicaceae , Humanos , Antioxidantes/farmacología , Antioxidantes/análisis , Brassicaceae/química , Células CACO-2 , Espectrometría de Masas en Tándem , Hojas de la Planta/química , Oxidación-Reducción , Agua/análisis
6.
Foods ; 11(22)2022 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-36429269

RESUMEN

A variety of metabolites contribute to the freshness and taste characteristics of seafood. This study investigated the effects of high hydrostatic pressure (HHP; 400, 500, and 600 MPa) for 10 min) on the metabolome of striped prawn during chilled storage, in relation to microorganisms' development. All treated samples showed lower viable counts throughout storage compared to the untreated counterparts. The limit of acceptability from a microbiological point of view was extended from 9 to as many as 35 days by 600 MPa treatment. Metabolites were quantified by 1H-NMR through a targeted-untargeted metabolomic approach. Molecules linked to nucleotides' degradation and amines' anabolism suggested an overall freshness improvement granted by HHP. Notably, putrescine and cadaverine were detected only in untreated prawn samples, suggesting the inactivation of degradative enzymes by HHP. The concentration of molecules that influence umami perception was significantly elevated by HHP, while in untreated samples, the concentration of molecules contributing to a sour taste gradually increased during storage. As metabolomics was applied in its untargeted form, it allowed us to follow the overall set of metabolites related to HHP processing and storage, thus providing novel insights into the freshness and taste quality of striped prawn as affected by high hydrostatic pressure.

7.
Foods ; 11(17)2022 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-36076877

RESUMEN

Chitosan (Ch) is a partially crystalline biopolymer, insoluble in pure water but soluble in acid solutions. It has attracted interest from researchers to prepare solutions using different acid types and concentrations. This research aims to study both the effect of chitosan (Ch) or acetic acid (Ac) concentrations, at different temperatures, on rheological and viscoelastic properties of Ch solutions. To study the effect of Ch, solutions were prepared with 0.5−2.5 g Ch/100 g of solution and Ac = 1%, whereas to study the effect of Ac, the solutions were prepared with 2.0 g of Ch/100 g of solution and Ac = 0.2−1.0%. Overall, all analyzed solutions behaved as pseudoplastic fluid. The Ch strongly affected rheological properties, the consistency index (K) increased and the index flow behavior (n) decreased as a function of Ch. The activation energy, defined as the energy required for the molecule of a fluid to move freely, was low for Ch = 0.5%. The effect of Ac was less evident. Both K and n varied according to a positive and negative, respectively, parabolic model as a function of Ac. Moreover, all solutions, irrespective of Ch and Ac, behaved as diluted solutions, with G" > G'. The relaxation exponent (n") was always higher than 0.5, confirming that these systems behaved as a viscoelastic liquid. This n" increased with Ch, but it was insensitive to Ac, being slightly higher at 45 °C.

8.
Foods ; 11(5)2022 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-35267364

RESUMEN

Vacuum impregnation is considered a cold formulation technology since it allows the incorporation of a desired functional compound into porous plant tissue without applying any heat. It is widely used in combination with the drying process to obtain added-value snacks. The aim of this work was to evaluate the effect of two trehalose concentrations (5 and 10% w/w) on: (i) the water state and texture evolution during the air drying (50 °C, 8 h) of apple snacks vacuum impregnated with blueberry juice, and on (ii) the colour of the final dried apple snacks. The results of nuclear magnetic resonance (NMR) showed that trehalose affects the water mobility of the samples during drying especially after 200-300 min of drying. In terms of textural properties, trehalose could increase the crispier characteristic of the samples impregnated with trehalose at the end of drying. Significative changes were found in terms of chroma and hue angle.

9.
J Sci Food Agric ; 102(11): 4961-4965, 2022 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-35244938

RESUMEN

BACKGROUND: Dry-salted cod (Gadus morhua) must be rehydrated before consumption and this step can take up to 5 days. Desalting of cod on an industrial scale poses many problems, mainly related to the long processing times and the quality of the final product. For this reason, many researchers have focused on finding new desalting methods to improve mass transfer. The application of pulsed electric fields (PEF) has been proposed as an alternative method for improving mass transfer in many food processes. However, there is no previous literature on the use of PEF to improve animal tissue rehydration. Therefore, the present study aimed to investigate the influence of two PEF pre-treatments [PEF (1) 500 V cm-1 and PEF (2) 1000 V cm-1 ] on mass transport kinetics during the rehydration process of salted cod. The rehydration process was carried out under static conditions for 6 days, immersing dry-salted cod samples in tap water (5 ± 0.5 °C). RESULTS: The results show that the use of PEF technology increases the rate of the rehydration process of dry-salted cod and influences the redistribution of salt. In general, the samples pre-treated with PEF showed higher weight gain and lower salt loss than the control samples during the rehydration process. CONCLUSION: The application of PEF prior to rehydration of salted cod samples could be of interest to the food industry as a result of a higher process yield (higher weight gain) and the possibility to reduce the water renewal because less NaCl is lost in the wastewater. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Asunto(s)
Gadus morhua , Animales , Fluidoterapia , Conservación de Alimentos/métodos , Cloruro de Sodio , Cloruro de Sodio Dietético , Agua , Aumento de Peso
10.
Foods ; 11(3)2022 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-35159638

RESUMEN

The aim of this study was to evaluate the effect of different solutions for vacuum impregnation (VI) of fresh-cut (FC) apples through an innovative multi-analytical approach. In particular, the individual and synergistic effects of ascorbic acid and calcium lactate on the preservation of freshness of FC apples was assessed through color, texture, microscopy, isothermal calorimetry, and time-domain nuclear magnetic resonance (TD-NMR) evaluations. The analysis was performed immediately after VI and after 24 h of refrigerated storage. The obtained results showed a good preservation of color and higher firmness in the impregnated samples. Concerning the metabolic heat production, a decrease following the VI treatment was observed, especially when the combined solution was used for the impregnation. The TD-NMR studies showed higher changes in terms of signal intensity and transversal relaxation time T2 after 24 h of storage, evidencing the meta-stability of the plant material for its dynamic tissue nature, and the dewatering/impregnation processes evolution until the achievement of dynamic equilibrium.

11.
Molecules ; 26(24)2021 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-34946772

RESUMEN

Plasma activated water (PAW) has proven to be a promising alternative for the decontamination of rocket leaves. The impact of PAW on the volatile profile, phytosterols, and pigment content of rocket leaves was studied. Leaves were treated by PAW at different times (2, 5, 10, and 20 min). Compounds of the headspace were detected and quantified using GC-MS analysis. A total of 52 volatile organic compounds of different chemical classes were identified. Glucosinolate hydrolysis products are the major chemical class. PAW application induced some chemical modifications in the volatile compounds. Changes in the content of the major compounds varied with the increase or decrease in the treatment time. However, PAW-10 and -2 were grouped closely to the control. A significant decrease in the content of ß-sitosterol and campesterol was observed after PAW treatment, except for PAW-10, which showed a non-significant reduction in both compounds. A significant increase in ß carotene, luteolin, and chlorophyll b was observed after the shortest treatment time of PAW-2. A reduction in chlorophyll content was also observed, which is significant only at longer treatment, or PAW-20. Overall, PAW has proven to be a safe alternative for rocket decontamination.


Asunto(s)
Brassicaceae/química , Hojas de la Planta/química , Gases em Plasma/química , Compuestos Orgánicos Volátiles/química , Agua/química
12.
Foods ; 10(9)2021 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-34574140

RESUMEN

The crustacean processing industry has experienced significant growth over recent decades resulting in the production of a great number of by-products. Crustacean by-products contain several valuable components such as proteins, lipids, and carotenoids, especially astaxanthin and chitin. When isolated, these valuable compounds are characterized by bioactivities such as anti-microbial, antioxidant, and anti-cancer ones, and that could be used as nutraceutical ingredients or additives in the food, pharmaceutical, and cosmetic industries. Different innovative non-thermal technologies have appeared as promising, safe, and efficient tools to recover these valuable compounds. This review aims at providing a summary of the main compounds that can be extracted from crustacean by-products, and of the results obtained by applying the main innovative non-thermal processes for recovering such high-value products. Moreover, from the perspective of the circular economy approach, specific case studies on some current applications of the recovered compounds in the seafood industry are presented. The extraction of valuable components from crustacean by-products, combined with the development of novel technological strategies aimed at their recovery and purification, will allow for important results related to the long-term sustainability of the seafood industry to be obtained. Furthermore, the reuse of extracted components in seafood products is an interesting strategy to increase the value of the seafood sector overall. However, to date, there are limited industrial applications for this promising approach.

13.
Heliyon ; 7(1): e05947, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33490691

RESUMEN

A combined effect of pulsed electric field application and salting in a brine with 5 and 10% w/w NaCl on oxidative stability of lipids and proteins, as well as color characteristics of sea bass samples, was assessed in the study. The applied intensity of the current was set at 10 and 20 A corresponding to 300 and 600 V cm-1, respectively. Pulsed electric field (PEF) treatment led to a significant (p < 0.05) increase in primary and secondary lipid oxidation products expressed as peroxide value, conjugated dienes and 2-thiobarbituric acid reactive substances in PEF-treated samples compared to untreated ones. Conjugated dienes, as unstable primary oxidation products, correlated with b∗-value (p < 0.05, R = 0.789), suggesting their contribution to the yellowness of the fish flesh due to fast decomposition and conversion into secondary oxidation products yielding yellow pigmentation. However, none of the fish samples treated at the higher current intensity of 20 A exceeded the acceptable level of 5 meq active oxygen/kg lipid according to the requirements of the Standard for fish oils CODEX STAN 329-2017, suggesting acceptable oxidative status quality of sea bass samples after the treatment. PEF-treated fish samples also showed a significant increase in Schiff bases and total carbonyls on day 5 and day 8 of brine salting compared to non-treated samples, revealing a strong effect of electroporation on protein oxidation.

14.
Foods ; 10(2)2021 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-33504106

RESUMEN

Pulsed electric field (PEF) is a non-thermal technology which is increasingly drawing the interest of the meat industry. This study aimed at evaluating the effect of PEF on the main technological properties of chicken meat, by investigating the role of the most relevant process parameters such as the number of pulses (150 vs. 300 and 450 vs. 600) and the electric field strength (0.60 vs. 1.20 kV/cm). Results indicated that PEF does not exert any effect on meat pH and just slightly affects lightness and yellowness. Low-intensity PEF treatments improved the water holding capacity of chicken meat by significantly (p < 0.001) reducing drip loss up to 28.5% during 4 days of refrigerated storage, without damaging proteins' integrity and functionality. Moreover, from the analysis of the process parameters, it has been possible to highlight that increasing the number of pulses is more effective in reducing meat drip loss rather than doubling the electric field strengths. From an industrial point of view, the results of this explorative study suggested the potential of PEF to reduce the undesired liquid inside the package, thus improving consumer acceptance.

15.
Foods ; 9(10)2020 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-33080879

RESUMEN

Despite their high nutritional value, high quantities of fish caught in the Adriatic Sea are underused or discarded for their insignificant economic value. Mechanical separation of flesh represents an opportunity for developing innovative semi-finished products, even if it can promote an increased quality degradation rate. The aim of this study was to evaluate physico-chemical modifications of mechanically separated mantis shrimp flesh during deep-freezing storage. Flesh samples obtained using a belt-drum separator, frozen and vacuum-packed, were stored at 3 temperatures (industrial: -26 °C; domestic: -18 °C and abuse: -10 °C) for 12 months. During storage, qualitative (color, water content, pH, fatty acids (FA) and lipid oxidation) were evaluated. Fish freshness parameters (e.g., trimethylamine (TMA), dimethylamine (DMA) and amino acids) were assessed using nuclear magnetic resonance (1H-NMR). The mechanical separation process accelerated the initial oxidation phenomena, promoting color alterations, compared to manual separation. The main degradation phenomena during storage were significantly affected by temperature and were related to changes in luminosity, oxidation of n-3 polyunsaturated fatty acids (PUFA), increased lipolysis with release of free FA, production of TMA and DMA by residual enzymatic activity, and changes in amino acids due to proteolysis. The inter-disciplinary approach permitted important findings to be made, in terms of the extent of different degradative phenomena, bound to processing and storage conditions of mechanically separated mantis flesh.

16.
J Food Sci Technol ; 56(10): 4404-4416, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31686672

RESUMEN

Vacuum impregnation (VI) has been recognized as a promising tool for the introduction of solutes into the internal structure of some porous food products. The enrichment of minimally processed potatoes with aromatic compounds could represent an interesting method for product innovation. This study was aimed at applying VI with rosemary essential oil on a minimally processed potato product in order to obtain an innovative fresh-cut potato product, and to evaluate its influence on the physico-chemical, sensorial and microbiological properties of potato sticks during refrigerated storage and after frying. A pressure of 60 mbar was applied for 30 min followed by a relaxation time at atmospheric pressure of 30 min to potato sticks immersed in rosemary oil solutions in concentration between 0 and 12%. Prepared samples were packed and stored at 4 °C for 14 days. Analytical determinations were carried out on the fresh and fried product. The weight gain of potatoes promoted by VI was in the range of 6-14%, depending on the concentration of rosemary essential oil. The rosemary essential oil concentration gradients of impregnated potato sticks were detected by GC analysis and sensorial test, evidencing their persistency during storage and after frying. The treatment seemed to improve microbiological stability, not affecting the texture, moisture, but slightly deteriorating the product color. Results obtained in the present study confirm the potentiality of VI for fresh products innovation.

17.
Food Chem ; 301: 125187, 2019 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-31387041

RESUMEN

Solid and liquid components coexist into glassy and amorphous structures of food complex matrixes. Both states admit movements, promoting physical modifications to a more thermodynamically stable system. Green and roasted coffee beans are principally characterized by a glassy structure that slowly evolves during storage. The aim of this study was to assess calorimetric and dielectric properties in combination, as a useful multi-analytical technique to improve the understanding of the motion mechanism of localized molecules. After equilibration at different water activities (aw) for the determination of sorption isotherms of green and roasted coffee, the glass transition temperature (Tg) of the samples has been measured by using differential scanning calorimetry (DSC). Increasing the aw from 0.155 to 0.512, the Tg shifted from 48.76 (±0.04) to 34.89 (±0.02) °C for green coffee and from 45.73 (±0.05) to 40.15 (±0.10) °C for the roasted one. The spectroscopic fingerprint of the matrix has been determined by dielectric measurements in terms of "gain" spectra (related to the imaginary part of permittivity). The maximum values of the determination coefficient (R2), obtained by linear correlation between spectral data and water activity or glass transition values for a specific frequency of the whole range (1.6 GHz-2.7 GHz), were 0.999 and 0.943 for green, and 0.997 R2 and 0.925 R2 for roasted coffee respectively.


Asunto(s)
Coffea/química , Café/química , Rastreo Diferencial de Calorimetría , Temperatura de Transición , Vitrificación , Agua/química
18.
Front Microbiol ; 10: 1737, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31417527

RESUMEN

Pulsed electric field (PEF) treatment is a non-thermal technology that has shown good potential for microbial inactivation. However, in many cases, it cannot be sufficient to avoid microbial proliferation, and the combination with other stabilizing technologies is needed. In the framework of the hurdle concept, several researches have been focused on the use of PEF in combination with heat and/or antimicrobials to increase its efficacy. This study investigated the inactivation effect of PEF on a strain of Saccharomyces cerevisiae (isolated from spoiled beverages) in a model system (growth medium). The efficacy of PEF treatment was evaluated in relation to different variables, such as electric field strength (25 and 50 kV/cm), treatment time (from 1 to 5 s), initial inoculum level (4 or 6 log cfu/ml), preheating at 50°C, medium pH (4 or 6), and addition of citral at sublethal concentration (i.e., half of minimum inhibiting concentration). The data from plate counting, modeled with the Weibull equation, showed that one of the main factors affecting yeast inactivation was the preheating of the suspension at 50°C. Indeed, higher cell load reductions were obtained with heat-assisted PEF, especially in the presence of citral. The effect of initial cell load was negligible, while pH affected yeast inactivation only without preheating, with higher death kinetics at pH 6. Flow cytometry (FCM) analysis confirmed higher mortality under these conditions. However, the occurrence of injured cells, especially in samples treated at pH 4, was observed. The ability of these cells to recover from the damages induced by treatments was affected by both citral and preheating. The synergic effects of PEF, preheating, and citral were likely due to the increase of membrane permeability (especially at pH 6), as the primary target of electroporation, which favored the solubilization of citral in the cell membrane, enhancing the efficacy of the whole process. The multi-analytical approach (traditional plate counting and FCM) allowed defining parameters to increase PEF efficacy against S. cerevisiae. Moreover, FCM, able to discriminate different physiological states of the yeast population, was helpful to better clarify the action mechanism and the potential recovery of cells after treatment.

19.
Food Chem ; 294: 260-266, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31126461

RESUMEN

This work studied water state of honey during crystallization, obtained statically and dynamically, by differential scanning calorimetry (DSC), water activity (aw) assessment and time domain nuclear magnetic resonance (TD-NMR). Crystallization was induced by adding 5% of crystallized honey to three honey samples with different fructose/glucose ratio, the key characteristic for honey crystallization. Samples were stored at 14 °C. Dynamic crystallization was obtained by using an impeller. DSC showed that the dynamic crystallization was faster than the static one, the latter characterized by two phases, showing different rates. The crystallization rate did not affect aw, that remained below 0.600. TD-NMR allowed to separately observe two kinds of protons, both pertaining to liquid sugars, one chemically exchanging with water and one not exchanging with it. The combination of techniques allowed speculating that the two crystallization methods led to crystals of different size and shape.


Asunto(s)
Miel/análisis , Agua/química , Rastreo Diferencial de Calorimetría , Cristalización , Espectroscopía de Resonancia Magnética
20.
Front Microbiol ; 10: 246, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30837971

RESUMEN

The increasing competition within the food industry sector makes the requisite of innovation in processes and products essential, leading to focus the interest on the application of new processing technologies including high pressure homogenization (HPH) and ultra high pressure homogenization (UHPH). In this context, the present research aimed at evaluating the effects of two UHPH treatments performed at 200 MPa for 2 and 3 cycles on quality and functionality of organic kiwifruit juice stored at three different temperatures, i.e., 5, 15, and 25°C. The results showed that only the treatment performed at 200 MPa for 3 cycles was able to significantly increase the shelf-life of organic kiwifruit juices when stored at refrigeration temperature, avoiding also phase separation that occurred in the sample treated at 0.1 MPa (control) after 20 days of refrigerated storage. The obtained data showed also that the highest applied pressure was able to increase some quality parameters of the juice such as viscosity and luminosity (L∗) and increased the availability of total phenol content consequently enhancing the juice total antioxidant activity. The application of a treatment at 200 MPa for 3 cycles allowed to obtain a stable kiwifruit juice for more than 40 days under refrigerated storage. A challenge to implement this technology in food process as full alternative to thermal treatment could be represented by the adoption of pressure level up to 400 MPa followed by the packaging in aseptic conditions.

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