Evaluation of Phosphatase Inactivation Kinetics in Milk Under Continuous Flow Microwave and Conventional Heating Conditions

Finding environmentally gentle methods to graft Lewis acid on the surface of mesoporous materials is a topic of current interest. Herein we describe the optimization of a preparation procedure of a mesoporous silica-supported ErIII catalyst using the microwave-assisted post-calcination functionalization of Mobil Composition of Matter-41 silica as the key step. The required time for functionalization was reduced from several hours to 10 min using sealed-vessel microwave technology. Control experiments using conventional heating at the same temperature demonstrated that the rate increase is owing to a simple thermal/kinetic effect as a result of the higher reaction temperature. The resulting ErIII catalyst was tested for the first time as a catalyst in the continuous flow deprotection of benzaldehyde dimethylacetal and a complete leaching study was performed.

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Vitamin B1 and B6 Retention in Milk after Continuous-Flow Microwave and Conventional Heating at High Temperatures

Journal of Food Protection ◽

10.4315/0362-028x-64.6.890 ◽

2001 ◽

Vol 64 (6) ◽

pp. 890-894 ◽

Cited By ~ 9

Author(s):

ISABEL SIERRA ◽

CONCEPCIÓN VIDAL-VALVERDE

Keyword(s):

High Temperatures ◽

Continuous Flow ◽

Vitamin B6 ◽

Vitamin B1 ◽

Raw Milk ◽

Microwave Treatment ◽

Conventional Heating ◽

Conventional System ◽

Tubular Heat Exchanger ◽

Heating And Cooling

The effect of continuous-flow microwave treatment at high temperatures on the retention of vitamins B1 and B6 in raw milk with different fat content was evaluated. Results were compared with those obtained using a conventional system (tubular heat exchanger) with the same heating and cooling phases. Heat treatment of whole (3.4% fat) and skim (0.5% fat) milk at 90°C produced no losses of vitamin B1 or vitamin B6 (pyridoxamine and pyridoxal). However, at 110 and 120°C, while vitamin B1 content of milk remained constant, pyridoxamine increased (4 to 5% and 9 to 11%, respectively) and pyridoxal decreased (5 to 6% and 9 to 12%, respectively). Under the assayed conditions, no differences were observed between the content of these vitamins in conventionally and continuous-flow microwave-treated milk.

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Assessment of the Thermal Treatment of Milk during Continuous Microwave and Conventional Heating

Journal of Food Protection ◽

10.4315/0362-028x-59.8.889 ◽

1996 ◽

Vol 59 (8) ◽

pp. 889-892 ◽

Cited By ~ 24

Author(s):

ROSINA LOPEZ-FANDIÑO ◽

MAR VILLAMIEL ◽

NIEVES CORZO ◽

AGUSTIN OLANO

Keyword(s):

Heat Treatment ◽

Continuous Flow ◽

Thermal Denaturation ◽

Microwave Treatment ◽

Conventional Heating ◽

Treatment Intensity ◽

Heat Distribution ◽

Conventional System ◽

Effective System ◽

Β Lactoglobulin

The effect of continuous-flow microwave treatment of milk was estimated by using indicators of the heat treatment intensity (β-lactoglobulin denaturation, inactivation of alkaline phosphatase and lactoperoxidase). Results were compared with those obtained using a conventional process having the same heating, holding, and cooling phases. Continuous microwave treatment proved to be an effective system for pasteurizing milk, with the inclusion of a holding phase to maintain the time and temperature conditions required. At high pasteurization temperatures, the extent of thermal denaturation observed with the microwave treatment was lower than that obtained with the conventional system. This result could be attributed to a better heat distribution and the lack of hot surfaces contacting the milk in the case of the microwave unit.

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