Adelmo Monsalve - Academia.edu (original) (raw)

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Papers by Adelmo Monsalve

Research paper thumbnail of Control of Browning During Storage of Apple Slices Preserved by Combined Methods. 4-Hexylresorcinol as Anti-Browning Agent

Journal of Food Science, 1993

Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonenzymatic browning in apple slices... more Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonenzymatic browning in apple slices preserved by combined methods was assessed during storage at four temperatures. Sodium sulfite and ascorbic acid-Zphosphate were used for comparison. Browning as measured by reflectance spectroscopy and based on visible light absorption was partially inhibited by 4-hexylresorcinol comparable to that of a fivefold sulfite concentration at 25°C. At temperature above 35"C, the inhibiting effect of 4-hexylresorcinol was minimal. Energy of activation of the browning reaction was 5-20 kcal/mol and was not affected by anti-browning treatment. Only induction time was delayed by the 4-hexylresorcinol and sulfite treatments.

Research paper thumbnail of Control of Browning During Storage of Apple Slices Preserved by Combined Methods. 4Hexylresorcinol as Anti-Browning Agent

Journal of Food Science, 1993

Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonen-zymatic browning in apple slice... more Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonen-zymatic browning in apple slices preserved by combined methods was assessed during storage at four temperatures. Sodium sulfite and ascorbic acid-2-phosphate were used for comparison. Browning as measured by reflectance spectroscopy and based on visible light absorption was partially inhibited by 4-hexylresorcinol comparable to that of a fivefold sulfite concentration at 25°C. At temperature above 35°C, the inhibiting effect of 4-hexylresorcinol was minimal. Energy of activation of the browning reaction was 5–20 kcal/mol and was not affected by anti-browning treatment. Only induction time was delayed by the 4-hexylresorcinol and sulfite treatments.

Research paper thumbnail of Mass Transfer and Textural Changes during Processing of Apples by Combined Methods

Journal of Food Science, 1993

Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic a... more Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic adjustment of aw by the combined method approach were studied at 30, 40 and 50°C. Mass transfer of water and sugar in the treated apple followed typical log-normal behavior with most changes occurring during early stages of the process. The changes followed Crank's equation for diffusion. A negative correlation between apple texture and sugar diffusion was observed. Softening, as well as mass transfer changes, occurred at early stages of osmotic treatment. The texture changes were most pronounced at the edges of the apple tissue where the sugar had penetrated. Softening and sugar uptake were more pronounced when apples were acidified. Apples became firm within 2 hr of the process, when the external layer of the apple cylinders penetrated by sugar was trimmed. Calcium chloride beyond 0.30% minimized tissue softening, but the typical crispy structure of the fresh apple was not restored.

Research paper thumbnail of Inactivation of Escherichia coli and Staphylococcus aureus in model foods by pulsed electric field technology

Food Research International, 1995

Inactivation of microorganisms exposed to high-voltage pulsed electric fields is a promising non-... more Inactivation of microorganisms exposed to high-voltage pulsed electric fields is a promising non-thermal food preservation technology. This paper demonstrates and validates the inactivation of Escherichia coli, a Gram-negative bacterium and Staphylococcus aureus, a Gram-positive bacterium, subjected to high-voltage electric field pulses. A four-log cycle reduction in microbial population is achieved in model foods such as simulated milk ultrafiltrate (SMUF) with a peak electric field strength of 16 kV/cm and 60 pulses with a pulse width ranging between 200 and 300 μs. The temperature of the cell suspension was kept below the lethal temperature, demonstrating that inactivation is not due to thermal effects induced by the pulses of high-voltage electricity. Thermal food preservation causes undesirable changes in the physical character, quality and nutrient content of foods. Non-thermal preservation techniques minimize the undesirable changes in foods. A comparison between the inactivation of microorganisms by high-voltage pulsed electric fields and thermal methods of food preservation is also discussed.

Research paper thumbnail of INACTIVATION of SACCHAROMYCES CEREVISIAE IN APPLE JUICE BY SQUARE-WAVE and EXPONENTIAL-DECAY PULSED ELECTRIC FIELDS

Journal of Food Process Engineering, 1994

With equivalent electrical energy input, inactivation of microorganisms by pulsed electric fields... more With equivalent electrical energy input, inactivation of microorganisms by pulsed electric fields depends on pulse waveform. Exponential-decay and square-wave pulsed electric fields were selected to treat Saccharomyces cerevisiae suspended in apple juice. A parallel-plate static treatment chamber with 25 ml volume and 0.95 cm electrode gap was used. Peak electric field and pulse electric energy input were 12 kV/cm and 260 Joules per pulse for both waveforms. Both waveforms were found effective in the microbial inactivation. However, inactivation of S. cerevisiae treated with square-wave pulses was greater than yeast treated with exponential-decay pulses. For the purpose of food pasteurization, square-wave pulsed electric fields may result in significant energy savings compared to exponential-decay pulses.

Research paper thumbnail of Control of Browning During Storage of Apple Slices Preserved by Combined Methods. 4-Hexylresorcinol as Anti-Browning Agent

Journal of Food Science, 1993

Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonenzymatic browning in apple slices... more Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonenzymatic browning in apple slices preserved by combined methods was assessed during storage at four temperatures. Sodium sulfite and ascorbic acid-Zphosphate were used for comparison. Browning as measured by reflectance spectroscopy and based on visible light absorption was partially inhibited by 4-hexylresorcinol comparable to that of a fivefold sulfite concentration at 25°C. At temperature above 35"C, the inhibiting effect of 4-hexylresorcinol was minimal. Energy of activation of the browning reaction was 5-20 kcal/mol and was not affected by anti-browning treatment. Only induction time was delayed by the 4-hexylresorcinol and sulfite treatments.

Research paper thumbnail of Control of Browning During Storage of Apple Slices Preserved by Combined Methods. 4Hexylresorcinol as Anti-Browning Agent

Journal of Food Science, 1993

Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonen-zymatic browning in apple slice... more Effectiveness of 4-hexylresorcinol to inhibit enzymatic and nonen-zymatic browning in apple slices preserved by combined methods was assessed during storage at four temperatures. Sodium sulfite and ascorbic acid-2-phosphate were used for comparison. Browning as measured by reflectance spectroscopy and based on visible light absorption was partially inhibited by 4-hexylresorcinol comparable to that of a fivefold sulfite concentration at 25°C. At temperature above 35°C, the inhibiting effect of 4-hexylresorcinol was minimal. Energy of activation of the browning reaction was 5–20 kcal/mol and was not affected by anti-browning treatment. Only induction time was delayed by the 4-hexylresorcinol and sulfite treatments.

Research paper thumbnail of Mass Transfer and Textural Changes during Processing of Apples by Combined Methods

Journal of Food Science, 1993

Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic a... more Mass transfer and textural changes of ‘Red Delicious’ apple slices and cylinders during osmotic adjustment of aw by the combined method approach were studied at 30, 40 and 50°C. Mass transfer of water and sugar in the treated apple followed typical log-normal behavior with most changes occurring during early stages of the process. The changes followed Crank's equation for diffusion. A negative correlation between apple texture and sugar diffusion was observed. Softening, as well as mass transfer changes, occurred at early stages of osmotic treatment. The texture changes were most pronounced at the edges of the apple tissue where the sugar had penetrated. Softening and sugar uptake were more pronounced when apples were acidified. Apples became firm within 2 hr of the process, when the external layer of the apple cylinders penetrated by sugar was trimmed. Calcium chloride beyond 0.30% minimized tissue softening, but the typical crispy structure of the fresh apple was not restored.

Research paper thumbnail of Inactivation of Escherichia coli and Staphylococcus aureus in model foods by pulsed electric field technology

Food Research International, 1995

Inactivation of microorganisms exposed to high-voltage pulsed electric fields is a promising non-... more Inactivation of microorganisms exposed to high-voltage pulsed electric fields is a promising non-thermal food preservation technology. This paper demonstrates and validates the inactivation of Escherichia coli, a Gram-negative bacterium and Staphylococcus aureus, a Gram-positive bacterium, subjected to high-voltage electric field pulses. A four-log cycle reduction in microbial population is achieved in model foods such as simulated milk ultrafiltrate (SMUF) with a peak electric field strength of 16 kV/cm and 60 pulses with a pulse width ranging between 200 and 300 μs. The temperature of the cell suspension was kept below the lethal temperature, demonstrating that inactivation is not due to thermal effects induced by the pulses of high-voltage electricity. Thermal food preservation causes undesirable changes in the physical character, quality and nutrient content of foods. Non-thermal preservation techniques minimize the undesirable changes in foods. A comparison between the inactivation of microorganisms by high-voltage pulsed electric fields and thermal methods of food preservation is also discussed.

Research paper thumbnail of INACTIVATION of SACCHAROMYCES CEREVISIAE IN APPLE JUICE BY SQUARE-WAVE and EXPONENTIAL-DECAY PULSED ELECTRIC FIELDS

Journal of Food Process Engineering, 1994

With equivalent electrical energy input, inactivation of microorganisms by pulsed electric fields... more With equivalent electrical energy input, inactivation of microorganisms by pulsed electric fields depends on pulse waveform. Exponential-decay and square-wave pulsed electric fields were selected to treat Saccharomyces cerevisiae suspended in apple juice. A parallel-plate static treatment chamber with 25 ml volume and 0.95 cm electrode gap was used. Peak electric field and pulse electric energy input were 12 kV/cm and 260 Joules per pulse for both waveforms. Both waveforms were found effective in the microbial inactivation. However, inactivation of S. cerevisiae treated with square-wave pulses was greater than yeast treated with exponential-decay pulses. For the purpose of food pasteurization, square-wave pulsed electric fields may result in significant energy savings compared to exponential-decay pulses.