A new method to determine “equilibrated” water activity and establish sorption isotherm by erasing surface history of the samples

Dupas-Langlet, Marina; Dupas, Julien; Samain, Sophie; Giardiello, Maria-Isabelle; Meunier, Vincent; Forny, Laurent

doi:10.1016/j.jfoodeng.2016.03.023

Cited by 10 publications

(15 citation statements)

References 21 publications

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“…Given these calculations, the observed losses in moisture during storage of roughly 1% to 2% weight for the stored lyophiles were attributed to moisture desorption. Similar moisture gains followed by losses have been observed during the equilibration of maltodextrins in desiccators over 21 d of storage at 25 °C at both 23% and 33% RH conditions (Dupas‐Langlet and others ). A lack of stable measurement after such a long equilibration time was attributed to the heterogeneity of amorphous solids and the complex mass transfer that may require a prolonged length of time to reach an equilibrium or meta‐stable condition.…”

Section: Resultssupporting

confidence: 74%

Degradation of L‐Ascorbic Acid in the Amorphous Solid State

Sanchez

Ismail

Christina

et al. 2018

Journal of Food Science

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Vitamin C is one of the most unstable vitamins in foods. This study documents that amorphous ascorbic acid is less stable than crystalline ascorbic acid in some environments (for example, higher temperatures within 1 wk), especially when the vitamin is present at low concentrations in a product. These findings increase the understanding of how material science properties influence the stability of vitamin C.

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Section: Resultssupporting

confidence: 74%

Degradation of L‐Ascorbic Acid in the Amorphous Solid State

Sanchez

Ismail

Christina

et al. 2018

Journal of Food Science

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“…The surface would therefore have a higher MC than the core during this initial period. Dupas‐Langlet et al demonstrated that such an effect can exist on products such as instant coffee and maltodextrin powders. The apparent a w of those products, which were shortly exposed to moist air, was significantly higher than the equilibrium a w , which was shown to take hours to reach.…”

Section: Resultsmentioning

confidence: 99%

Shelf life prediction of oxygen‐sensitive products: The influence of moisture on prediction accuracy for freeze‐dried coffee

et al. 2019

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Optimised packaging requires that properties are matched to the protection requirements of food for its shelf life duration. Benefits include reduced packaging costs, use volumes, and potentially improved environmental performance. The ability to predict product shelf life in different materials can assist in selecting optimal packaging. However, the availability of such tools is limited, and risk for over packing exists. The aim with this work is to develop a prediction approach which can be applied to assist users to select more optimal packaging materials. Soluble coffee was used to develop the approach, where oxygen consumption of the product is used as a quality indicator. The effect of moisture content on O2 consumption was studied to determine its influence on prediction accuracy. Samples were prepared with different levels of moisture content. O2 consumption rates were measured, and a notable influence of moisture was observed. A model was developed to predict the O2 consumption of the product when packed in a pouch. The model considers oxygen and moisture permeation properties of the packaging film, O2 and moisture differential between the interior and exterior of the packaging, and the evolution of the O2 consumption rate as a function of moisture increase. To test model accuracy, coffee samples were packed in flexible pouches, and O2 consumption was measured which showed that predicted and measured values shared the same trend characteristics. We show that considering both moisture and O2 ingress simultaneously leads to more precise shelf life prediction as oxidation rate is influenced by moisture content.

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“…The physicochemical status of water in food is generally affected by the water‐binding capacity of active cites, the effect of water‐soluble food components on the colligative properties of water, the surface structure and the capillary properties of food. The total effects of these parameters can only be measured by sorption isotherms (Dupas‐Langlet et al, 2016; Erbaş, Candal, Kılıç, & Mutlu, 2016; Viganó et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Sorption isotherm is the relationship between moisture content ( m ) and water activity ( a w ) of a sample at constant temperature ( T ) and that is described by m = ƒ( a w ) T equation. Sorption isotherm is obtained by the way of plotting the sample's moisture content against its water activity (Dupas‐Langlet et al, 2016; Erbaş, Candal, et al, 2016; Labuza, 1970).…”

Section: Introductionmentioning

confidence: 99%

Sorption isotherms of coffee in different stages for producing Turkish coffee

Mutlu

Candal‐Uslu

Kılıç‐Büyükkurt

et al. 2020

J Food Process Preserv

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The aim of this research was to determine the adsorption behavior of coffee as green and roasted beans and ground. For this aim, the static gravimetric method was used and samples were kept in the different water activity levels between 0.01 and 0.91 at 25°C for 7 days. The data were evaluated using the BET (Brunauer‐Emmett‐Teller), GAB (Guggenheim, Anderson and deBoer), Halsey, and Peleg sorption equations. The constants m0 and C of BET and GAB equations were determined to be between 2.13 and 6.61 g water/100 g of dry matter and 30.05–429.60, respectively. The isotherms of all coffee samples were defined as Type II because the C constant of the GAB equation was higher than 2. Additionally; the BET, GAB, and Peleg equations were determined to fit better than the Halsey for adsorption properties of coffee because E% values were lower than 10% and the coefficient of regression values approached the 1.00. Practical applications The obtained results with that research could be useful for understanding the physicochemical relationship between water and dry matter of coffee. Because this relationship is quite important in foods that have easily changing characteristics and quality like coffee, and determination of their sorption characteristics ensures maintaining the physical, chemical, biochemical, and microbiological quality stability of food during processing, packaging, and storage.

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A new method to determine “equilibrated” water activity and establish sorption isotherm by erasing surface history of the samples

Cited by 10 publications

References 21 publications

Degradation of L‐Ascorbic Acid in the Amorphous Solid State

Degradation of L‐Ascorbic Acid in the Amorphous Solid State

Shelf life prediction of oxygen‐sensitive products: The influence of moisture on prediction accuracy for freeze‐dried coffee

Sorption isotherms of coffee in different stages for producing Turkish coffee

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