Analysis of a Vapor Pressure Manometer for Measurement of Water Activity in Nonfat Dry Milk

Sood, Vivek; Heldman, Dennis R.

doi:10.1111/j.1365-2621.1974.tb07298.x

Cited by 19 publications

(5 citation statements)

References 2 publications

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“…The VPM method has been used to obtain the MSI of cereal grains and rape [61], dry milk [62], sesame seed [63], cowpea [64] and palm kernels [65].…”

Section: Vapor Pressure Manometric (Vpm) Methodsmentioning

confidence: 99%

Moisture Sorption Isotherms and Isotherm Model Performance Evaluation for Food and Agricultural Products

Aviara¹

2020

Sorption in 2020s

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Moisture sorption characteristics of agricultural and food products play important roles in such technological processes as drying, handling, packaging, storage, mixing, freeze-drying and other processes that require the prediction of food stability, shelf life, glass transition and estimation of drying time and texture and prevention of deteriorative reactions. They are useful in the computation of thermodynamic energies of moisture in the products. An understanding of moisture sorption phenomena in products, moisture sorption isotherm (MSI) determination techniques and moisture sorption isotherm model evaluation procedures would be useful in the development or selection, modeling and controlling as well as optimization of appropriate processes to make for enhanced efficiency. The phenomena addressed in this chapter are equilibrium moisture content (EMC)-water activity (a w) relationships and MSI types, temperature influence on isotherms and occurrence of moisture sorption hysteresis. MSI measurement techniques highlighted are the gravimetric, vapor pressure manometric (VPM), hygrometric and inverse gas chromatographic and the use of AquaLab equipment. Commonly used moisture sorption isotherm models (BET, GAB, modified GAB, Hailwood-Horrobin, modified Hailwood-Horrobin, modified Halsey, modified Henderson, modified Chung-Pfost and modified Oswin) were selected, and their evaluation procedures using moisture sorption data were outlined. Static gravimetric technique involving the use of saturated salt solution appears to be the most widely used and recommended method of determining the EMC of agricultural and food products. Most of the MSI models can be fitted to moisture sorption data thorough linearization by logarithmic transformation, while others can be solved using such expression as second-order polynomial. Model goodness of fit can be determined using standard (SE) error of estimate, coefficient of determination (R 2), mean relative percentage deviation (P) and fraction explained variation (FEV). The acceptance of a model depends on the nature of its residual plots. A model is considered acceptable if the residual plots show uniform scatter around the horizontal value of zero showing no systemic tendency towards a clear pattern. A model is better than another model if it has lower SE, lower P, higher R 2 and higher FEV. Although it appears as if a generalized MSI model is yet to exist, it is recommended that the Ngoddy-Bakker-Arkema (NBA) model should be given thorough going and extensive testing on the MSI of different categories of food as it could prove true to its generalized model posture due to the fundamental nature of its derivation.

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“…The VPM method has been used to obtain the MSI of cereal grains and rape [61], dry milk [62], sesame seed [63], cowpea [64] and palm kernels [65].…”

Section: Vapor Pressure Manometric (Vpm) Methodsmentioning

confidence: 99%

Moisture Sorption Isotherms and Isotherm Model Performance Evaluation for Food and Agricultural Products

Aviara¹

2020

Sorption in 2020s

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“…This method was improved by Taylor (), Labuza et al (), and Troller (). Sood and Heldman (), Labuza et al (), and Lewicki et al () studied design features, accuracy, and precision of the VPM. Troller () and Zanoni et al () discussed the design and setup of a water vapor pressure capacitance manometer.…”

Section: Commentarymentioning

confidence: 99%

Direct Manometric Determination of Vapor Pressure

Rahman

Sablani

Guizani

et al. 2001

Current Protocols in Food Analytical Chemistry

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“…Water activity of a sample is currently measured by various techniques, all assuming the thermodynamic equilibrium between a small volume of air and the sample. These techniques include vapour pressure manometers (Lewicki, 1987;Makower & Myers, 1943;Sood & Heldman, 1974;Troller, 1983;Zanoni, Peri, Giovanelli, & Pagliarini, 1999), electrical or cooled mirror dewpoint hygrometers (Richard & Labuza, 1990;Roa & Tapia de Daza, 1991;Yu, Schmidt, & Schmidt, 2009), and on to headspace gas chromatography (Nelson, Powlus, Gbeddy, Lavrich, & Mahajan, 2007). Among the factors influencing the organoleptic properties of the cheese (pH, temperature, enzymatic activities, etc.…”

Section: Introductionmentioning

confidence: 99%

Time-course estimation of evaporated water fluxes together with mean surface water activity in uncooked pressed cheeses during ripening using a purpose-built micro-bioreactor

Page

Dachraoui

Daudin

et al. 2012

International Dairy Journal

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Analysis of a Vapor Pressure Manometer for Measurement of Water Activity in Nonfat Dry Milk

Cited by 19 publications

References 2 publications

Moisture Sorption Isotherms and Isotherm Model Performance Evaluation for Food and Agricultural Products

Moisture Sorption Isotherms and Isotherm Model Performance Evaluation for Food and Agricultural Products

Direct Manometric Determination of Vapor Pressure

Time-course estimation of evaporated water fluxes together with mean surface water activity in uncooked pressed cheeses during ripening using a purpose-built micro-bioreactor

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