Use of time-resolved fluorescence to monitor bioactive compounds in plant based foodstuffs

The study of compounds that exhibit antioxidant activity has recently received much interest in the food industry because of their potential health benefits. Most of these compounds are plant based, such as polyphenolics and carotenoids, and there is a need to monitor them from the field through processing and into the body. Ideally, a monitoring technique should be non-invasive with the potential for remote capabilities. The application of the phenomenon of fluorescence has proved to be well suited, as many plant associated compounds exhibit fluorescence. The photophysical behaviour of fluorescent molecules is also highly dependent on their microenvironment, making them suitable probes to monitor changes in pH, viscosity and polarity, for example. Time-resolved fluorescence techniques have recently come to the fore, as they offer the ability to obtain more information, coupled with the fact that the fluorescence lifetime is an absolute measure, while steady state just provides relative and average information. In this work, we will present illustrative time-resolved measurements, rather than a comprehensive review, to show the potential of time-resolved fluorescence applied to the study of bioactive substances. The aim is to help assess if any changes occur in their form, going from extraction via storage and cooking to the interaction with serum albumin, a principal blood transport protein

Furan and 5-hydroxymethylfurfural removal from high- and low-moisture foods

Foods with different moisture and fat contents (i.e. meat sauce and biscuits) were subjected to treatments at 4, 12 and 19 kPa for increasing lengths of time to remove furan and 5-hydroxymethylfurfural (HMF). The vacuum treatments were ineffective in removing HMF from both food types, as well as furan from the biscuits, unless this food was preliminary hydrated at high water activity. However, the vacuum treatments allowed furan to be removed from the high moisture food. In particular, 67% furan removal from the meat sauce was achieved by applying 12 kPa for 10 min. Sensory analysis results showed that meat sauce subjected to such a treatment presented the same odor intensity of the untreated sample. The post-process vacuum treatment could represent a reliable strategy to mitigate the furan levels in high moisture foods

Use of time-resolved spectroscopy as a method to monitor carotenoids present in tomato extract obtained using ultrasound treatment

Introduction Compounds exhibiting antioxidant activity have received much interest in the food industry because of their potential health benefits. Carotenoids such as lycopene, which in the human diet mainly derives from tomatoes (Solanum lycopersicum), have attracted much attention in this aspect and the study of their extraction, processing and storage procedures is of importance. Optical techniques potentially offer advantageous non-invasive and specific methods to monitor them. Objectives To obtain both fluorescence and Raman information to ascertain if ultrasound assisted extraction from tomato pulp has a detrimental effect on lycopene. Method Use of time-resolved fluorescence spectroscopy to monitor carotenoids in a hexane extract obtained from tomato pulp with application of ultrasound treatment (583 kHz). The resultant spectra were a combination of scattering and fluorescence. Because of their different timescales, decay associated spectra could be used to separate fluorescence and Raman information. This simultaneous acquisition of two complementary techniques was coupled with a very high time-resolution fluorescence lifetime measurement of the lycopene. Results Spectroscopic data showed the presence of phytofluene and chlorophyll in addition to lycopene in the tomato extract. The time-resolved spectral measurement containing both fluorescence and Raman data, coupled with high resolution time-resolved measurements, where a lifetime of ~5 ps was attributed to lycopene, indicated lycopene appeared unaltered by ultrasound treatment. Detrimental changes were, however, observed in both chlorophyll and phytofluene contributions. Conclusion Extracted lycopene appeared unaffected by ultrasound treatment, while other constituents (chlorophyll and phytofluene) were degraded. Copyright \ua9 2015 John Wiley & Sons, Ltd

Effect of ultrasound treatment, oil addition and storage time on lycopene stability and in vitro bioaccessibility of tomato pulp

This study was performed to investigate the influence of ultrasound processing on tomato pulp containing no sunflower oil, or increasing amounts (i.e. 2.5%, 5% and 10%), on lycopene concentration and in vitro bioaccessibility at time zero and during storage at 5 \ub0C. Results confirmed previous findings in that ultrasonication was responsible for cell breakage and subsequent lycopene release in a highly viscous matrix. Neither the ultrasound process nor oil addition affected lycopene concentration. A decrease of approximately 35% lycopene content occurred at storage times longer than 15 days, due to isomerisation and oxidation reactions. No differences in lycopene in vitro bioaccessibility were found between the untreated and ultrasonically treated samples; this parameter decreased as a consequence of oil addition. Losses of lycopene in vitro bioaccessibility ranging between 50% and 80% occurred in the untreated and ultrasonically treated tomato pulps with and without oil during storage, mainly due to carotenoid degradation

Power ultrasound decontamination of wastewater from fresh-cut lettuce washing for potential water recycling

The decontamination effect of pulsed and continuous power ultrasound, provided at either controlled or uncontrolled temperature regimes, was studiedwith reference to nativemicroflora and inoculated pathogenic bacteria in wastewater obtained by fresh-cut lamb's lettuce washing. Results showed that decontamination efficacy increased with increasing specific energy and was higher when ultrasound treatment was provided under uncontrolled temperature regime. Continuous ultrasound supplied without temperature control allowed to achieve 3.2 Log reductions of native microflora during 20 min treatment, while 5 Log reductions of inoculated Listeria monocytogenes, Escherichia coli and Salmonella enterica were attained within 5 min of ultrasonication. The heat generated during continuous ultrasound accounted for approximately 58% of the total decontamination effect against L. monocytogenes, while it contributed for 100% to E. coli and S. enterica inactivation. Industrial relevance: The application of power ultrasound combined with in situ generated heat could represent an effective tool for water decontamination and recycling in the fresh-cut industry. In addition, besides safety requirements, this technology would also meet cost-effectiveness criteria and existing standards

Effect of high pressure homogenization and high power ultrasound on some physical properties of tomato juices with different concentration levels

The effect of high pressure homogenization (HPH) and ultrasound (US) on rheological properties, color, precipitate weight ratio, pectin esterification degree and cell integrity of tomato juices with different soluble solids content (5.0, 7.5, 10.0 Brix) was studied. Samples were subjected to HPH up to 150 MPa or US up to 30 min. The energy efficiency associated to the processes was also evaluated. Results showed that stress type and product concentration influenced the changes of tomato juice physical properties. In particular, HPH and US treatments were responsible for higher G0 and consistency of processed tomato juices than untreated samples. Increases in sample rheological properties were comparable for the 5.0 and 7.5 Brix treated HPH and US samples, whereas HPH was more effective than US in the case of 10.0 Brix sample. These changes were in agreement with other indexes, i.e. precipitate weight ratio increase and cell integrity decrease, and were attributed to stronger of inter-particle interactions. The process energy efficiency showed that lower energy was involved in HPH in comparison to US

Nanoemulsions as delivery systems of hydrophobic silybin from silymarin extract: Effect of oil type on silybin solubility, invitro bioaccessibility and stability

The potential of nanoemulsion delivery systems to carry silybin from silymarin extract was studied. To this purpose, sunflower oil, extra virgin olive oil and castor oil were used to prepare silymarin loaded nanoemulsions. The effect of oil type on the silybin solubility and i. n vitro bioaccessibility was evaluated. Moreover, the changes in particle size, silybin concentration, oxygen consumption and hydroperoxide concentration were studied in nanoemulsions during storage at 20\ub0C. Results showed that silybin can be successfully incorporated into physically stable nanoemulsions prepared with the different oils. The oil type slightly influenced the silybin invitro bioaccessibility, while it affected the nanoemulsion particle size as well as silybin stability during storage. In particular, silybin underwent degradation, showing lower stability in extra virgin oil and sunflower oil than in castor oil. Results also showed that the presence of the silymarin extract containing silybin did not affect the oxidation kinetics of the carrier oils. \ua9 2015 Elsevier Ltd

Efficient management of the water resource in the fresh-cut industry: Current status and perspectives

Among the different food industries, fresh-cut produce manufacturing is one of the major water-intensive, due to the huge consumption of potable water to perform washing operations required to guarantee the safety and quality of the product. Reducing the water footprint of washing is thus a challenge for fresh-cut industries and food researchers. This review paper examines the current status of the water resource management in the fresh-cut industry and critically describes a comprehensive approach to the improvement of the water use efficiency by implementing strategies of water recirculation, reuse and recycling. In particular, advantages and limitations of chlorine and chlorine-free disinfectants to reduce water turnover in washing tanks were considered. In addition, particular attention was focussed on innovative technological solutions, based on either physical or chemical stresses, which could be exploited individually or in combination to treat wastewater deriving from fresh-cut washing and allow its recycling within the processing plant. \ua9 2015 Elsevier Lt