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Papers by Alejandro RIVAS SOLER

Research paper thumbnail of Alimentary and Pharmaceutical Approach to Natural Antimicrobials against Clostridioides difficile Gastrointestinal Infection

Foods, 2021

Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due t... more Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due to different factors, namely (i) extended use of broad-spectrum antibiotics, (ii) transmission within asymptomatic and susceptible patients, and (iii) unbalanced gastrointestinal microbiome and collateral diseases that favor C. difficile gastrointestinal domination and toxin production. Although antibiotic therapies have resulted in successful control of CDI in the last 20 years, the development of novel strategies is urged in order to combat the capability of C. difficile to generate and acquire resistance to conventional treatments and its consequent proliferation. In this regard, vegetable and marine bioactives have emerged as alternative and effective molecules to fight against this concerning pathogen. The present review examines the effectiveness of natural antimicrobials from vegetable and algae origin that have been used experimentally in in vitro and in vivo settings to prevent a...

Research paper thumbnail of Effect of PEF and heat pasteurization on the physical–chemical characteristics of blended orange and carrot juice

LWT - Food Science and Technology, 2006

The effect of different Pulsed Electric Fields (PEF) intensities (25 kV/cm and 280 ms, P1; and 25... more The effect of different Pulsed Electric Fields (PEF) intensities (25 kV/cm and 280 ms, P1; and 25 kV/cm and 330 ms, P2) and conventional HTST treatment (98 1C, 21 s, T) on quality characteristics (pH, 1Brix, total acidity, turbidity, hydroxymethylfurfural (HMF), color, microbial flora, pectinmethylesterase (PME) activity, and sensory analysis) of blended orange and carrot juice were investigated. HMF, L* (luminosity) and C* (saturation or chrome) color parameters did not vary with any of the treatments. Total acidity and turbidity were slightly higher after HTST treatment. Sensory characteristics of the PEF-treated juice were more similar to the untreated juice than the HTST-pasteurized juice. Nevertheless, heat pasteurization (98 1C, 21 s) was more efficient in inactivating microbial flora and PME and preventing the growth of microbial flora and reactivation of PME at 2 and 12 1C for 10 weeks. However, the shelf-life of the PEF-treated juice was established as 4 weeks at 2 1C. This appears to be a reasonable shelf-life for this type of foodstuff.

Research paper thumbnail of Pulsed electric fields inactivation of Lactobacillus plantarum in an orange juice–milk based beverage: Effect of process parameters

Journal of Food Engineering, 2007

This work studies the effect of electric field strength, treatment time, process temperature, and... more This work studies the effect of electric field strength, treatment time, process temperature, and pulse width on the inactivation of Lactobacillus plantarum inoculated in an orange juice-milk based beverage. For any given quantity of energy applied, the highest degree of inactivation was achieved with high field intensities and short treatment times. The inactivation curve had different slopes, one up to application of 200-285 • 10 3 J L À1 , a second stage up to application of 813-891 • 10 3 J L À1 in which the inactivation did not increase significantly, and a third stage up to application of 1069-1170 • 10 3 J L À1. When the process temperature was raised to 55°C the inactivation increased by 0.5 cycles, achieving an energy saving of up to 60%. No increase in inactivation was achieved when the pulse width was increased from 2.5 • 10 À6 to 4 • 10 À6 s. The inactivation achieved with L. plantarum in this beverage is less than that reported by other authors in foods with a simpler composition.

Research paper thumbnail of Effects of pulsed electric fields on water-soluble vitamins and ACE inhibitory peptides added to a mixed orange juice and milk beverage

Food Chemistry, 2007

The effects of pulsed electric fields technology (15-40 kV/cm; 0-700 ls) and thermal processing (... more The effects of pulsed electric fields technology (15-40 kV/cm; 0-700 ls) and thermal processing (84°C and 95°C, 15-120 s) were studied on an orange juice and milk mixed beverage fortified with water-soluble vitamins (biotin, folic acid, pantothenic acid and riboflavin) and angiotensin-I-converting enzyme (ACE) inhibitory peptides. The evaluation of the technologies was carried out from two points of view: effect of treatments and effect of storage (4°C, 81 days). The results confirmed the stability of the vitamins and the ACE inhibitory activity after the PEF treatment and during storage.

Research paper thumbnail of Effect of temperature and substrate on Pef inactivation of Lactobacillus plantarum in an orange juice–milk beverage

European Food Research and Technology, 2006

The inactivation kinetics of Lactobacillus plantarum in an orange juice-milk beverage treated by ... more The inactivation kinetics of Lactobacillus plantarum in an orange juice-milk beverage treated by Pulsed Electric Fields (PEF) were studied. Experimental data were fitted to Bigelow and Hülsheger kinetic models and Weibull frequency distribution function. Results indicate that both Hülsheger model and Weibull function fit well the experimental data being Accuracy factor values (Af) closer to 1 and Mean Square Error (MSE) closer to 0. The tcw parameter of the Weibull model can be considered as a kinetic indicator as it expresses the microorganism's resistance to treatment by electric pulses. An increase in temperature favoured the inactivation of L. plantarum by PEF as reflected by a decreased in tcw value. Under the same conditions to those studied by other authors we reached less inactivation of L. plantarum in the beverage used in this study than in substrates with a simpler composition.

Research paper thumbnail of Nature of the inactivation of Escherichia coli suspended in an orange juice and milk beverage

European Food Research and Technology, 2006

The killing effect of pulsed electric fields (PEF) on Escherichia coli (ATCC 8739) suspended in a... more The killing effect of pulsed electric fields (PEF) on Escherichia coli (ATCC 8739) suspended in an orange juice and milk beverage was studied. Bipolar square pulses with a pulse width of 2.5 µs were applied. Electric field strength and treatment times ranged from 15 to 40 kV/cm, and from 0 to 700 µs, respectively. A maximum of 3.83 log reductions was achieved at 15 kV/cm and 700 µs. The experimental data were fitted to Bigelow and Hülsheger models and Weibull distribution function. Results indicated that Weibull function best described the experimental data (lowest mean square error). As there were no significant differences in the values of the shape factor (n) at the electric field strength of 25-40 kV/cm, the number of parameters in the Weibull model were reduced, leading to a simplified model with a fit similar to that obtained with the full model.

Research paper thumbnail of Alimentary and Pharmaceutical Approach to Natural Antimicrobials against Clostridioides difficile Gastrointestinal Infection

Foods, 2021

Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due t... more Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due to different factors, namely (i) extended use of broad-spectrum antibiotics, (ii) transmission within asymptomatic and susceptible patients, and (iii) unbalanced gastrointestinal microbiome and collateral diseases that favor C. difficile gastrointestinal domination and toxin production. Although antibiotic therapies have resulted in successful control of CDI in the last 20 years, the development of novel strategies is urged in order to combat the capability of C. difficile to generate and acquire resistance to conventional treatments and its consequent proliferation. In this regard, vegetable and marine bioactives have emerged as alternative and effective molecules to fight against this concerning pathogen. The present review examines the effectiveness of natural antimicrobials from vegetable and algae origin that have been used experimentally in in vitro and in vivo settings to prevent a...

Research paper thumbnail of Effect of PEF and heat pasteurization on the physical–chemical characteristics of blended orange and carrot juice

LWT - Food Science and Technology, 2006

The effect of different Pulsed Electric Fields (PEF) intensities (25 kV/cm and 280 ms, P1; and 25... more The effect of different Pulsed Electric Fields (PEF) intensities (25 kV/cm and 280 ms, P1; and 25 kV/cm and 330 ms, P2) and conventional HTST treatment (98 1C, 21 s, T) on quality characteristics (pH, 1Brix, total acidity, turbidity, hydroxymethylfurfural (HMF), color, microbial flora, pectinmethylesterase (PME) activity, and sensory analysis) of blended orange and carrot juice were investigated. HMF, L* (luminosity) and C* (saturation or chrome) color parameters did not vary with any of the treatments. Total acidity and turbidity were slightly higher after HTST treatment. Sensory characteristics of the PEF-treated juice were more similar to the untreated juice than the HTST-pasteurized juice. Nevertheless, heat pasteurization (98 1C, 21 s) was more efficient in inactivating microbial flora and PME and preventing the growth of microbial flora and reactivation of PME at 2 and 12 1C for 10 weeks. However, the shelf-life of the PEF-treated juice was established as 4 weeks at 2 1C. This appears to be a reasonable shelf-life for this type of foodstuff.

Research paper thumbnail of Pulsed electric fields inactivation of Lactobacillus plantarum in an orange juice–milk based beverage: Effect of process parameters

Journal of Food Engineering, 2007

This work studies the effect of electric field strength, treatment time, process temperature, and... more This work studies the effect of electric field strength, treatment time, process temperature, and pulse width on the inactivation of Lactobacillus plantarum inoculated in an orange juice-milk based beverage. For any given quantity of energy applied, the highest degree of inactivation was achieved with high field intensities and short treatment times. The inactivation curve had different slopes, one up to application of 200-285 • 10 3 J L À1 , a second stage up to application of 813-891 • 10 3 J L À1 in which the inactivation did not increase significantly, and a third stage up to application of 1069-1170 • 10 3 J L À1. When the process temperature was raised to 55°C the inactivation increased by 0.5 cycles, achieving an energy saving of up to 60%. No increase in inactivation was achieved when the pulse width was increased from 2.5 • 10 À6 to 4 • 10 À6 s. The inactivation achieved with L. plantarum in this beverage is less than that reported by other authors in foods with a simpler composition.

Research paper thumbnail of Effects of pulsed electric fields on water-soluble vitamins and ACE inhibitory peptides added to a mixed orange juice and milk beverage

Food Chemistry, 2007

The effects of pulsed electric fields technology (15-40 kV/cm; 0-700 ls) and thermal processing (... more The effects of pulsed electric fields technology (15-40 kV/cm; 0-700 ls) and thermal processing (84°C and 95°C, 15-120 s) were studied on an orange juice and milk mixed beverage fortified with water-soluble vitamins (biotin, folic acid, pantothenic acid and riboflavin) and angiotensin-I-converting enzyme (ACE) inhibitory peptides. The evaluation of the technologies was carried out from two points of view: effect of treatments and effect of storage (4°C, 81 days). The results confirmed the stability of the vitamins and the ACE inhibitory activity after the PEF treatment and during storage.

Research paper thumbnail of Effect of temperature and substrate on Pef inactivation of Lactobacillus plantarum in an orange juice–milk beverage

European Food Research and Technology, 2006

The inactivation kinetics of Lactobacillus plantarum in an orange juice-milk beverage treated by ... more The inactivation kinetics of Lactobacillus plantarum in an orange juice-milk beverage treated by Pulsed Electric Fields (PEF) were studied. Experimental data were fitted to Bigelow and Hülsheger kinetic models and Weibull frequency distribution function. Results indicate that both Hülsheger model and Weibull function fit well the experimental data being Accuracy factor values (Af) closer to 1 and Mean Square Error (MSE) closer to 0. The tcw parameter of the Weibull model can be considered as a kinetic indicator as it expresses the microorganism's resistance to treatment by electric pulses. An increase in temperature favoured the inactivation of L. plantarum by PEF as reflected by a decreased in tcw value. Under the same conditions to those studied by other authors we reached less inactivation of L. plantarum in the beverage used in this study than in substrates with a simpler composition.

Research paper thumbnail of Nature of the inactivation of Escherichia coli suspended in an orange juice and milk beverage

European Food Research and Technology, 2006

The killing effect of pulsed electric fields (PEF) on Escherichia coli (ATCC 8739) suspended in a... more The killing effect of pulsed electric fields (PEF) on Escherichia coli (ATCC 8739) suspended in an orange juice and milk beverage was studied. Bipolar square pulses with a pulse width of 2.5 µs were applied. Electric field strength and treatment times ranged from 15 to 40 kV/cm, and from 0 to 700 µs, respectively. A maximum of 3.83 log reductions was achieved at 15 kV/cm and 700 µs. The experimental data were fitted to Bigelow and Hülsheger models and Weibull distribution function. Results indicated that Weibull function best described the experimental data (lowest mean square error). As there were no significant differences in the values of the shape factor (n) at the electric field strength of 25-40 kV/cm, the number of parameters in the Weibull model were reduced, leading to a simplified model with a fit similar to that obtained with the full model.