Adsorption Isotherms of Maria Biscuits from Different Brands

Abstract

This study aimed to determine the adsorption curves of Maria biscuits from different brands at temperatures of 25 and 40C. The equilibrium between the sample and the atmosphere was achieved by placing the samples inside flasks containing saturated salts, at the temperatures studied for 5 days, to allow reaching equilibrium.From the results, it was possible to observe that by increasing the temperature, the stability of the product is augmented, as for the same moisture content the water activity is greatly reduced. Four sorption models were fitted with the adsorption data, but the Guggenheim-Anderson-deBoer and Henderson were better than the other models tested. In addition, the monolayer moisture content at temperature of 25C ranged between 0.0495 and 0.1981 g water/g dry basis, and at the temperature of 40C this parameter varied between 0.0529 and 0.1960 g water/g dry basis. PRACTICAL APPLICATIONSThe importance of stability for bakery products is critical for the maintenance of physical-chemical properties, and in particular to avoid spoilage and maintain texture. Biscuits are very hygroscopic and therefore, if not properly stored, tend to absorb water from the air, thus compromising texture. Knowledge about adsorption isotherms provides valuable information regarding the stability of products under some conditions. Therefore, the study undertaken in this work could be utilized to select the best storage and package conditions so as to improve product quality, moreover because Maria biscuits are largely consumed and appreciated for their crispy texture.

Moisture adsorption behaviour of biscuit during storage investigated by using a new Dynamic Dewpoint method

“…1a, b) exhibited a tendency to change shape during storage time, showing, according to BET classification, the characteristics type III shape (or 'J' shaped) during the first five days of storage; after this period the shape they assumed was more similar to a sigmoid-curve of type II. Above 0.75 a w the curves showed a steep rise attributable to the dissolution of sugars in the product aqueous phase (Bourlieu et al, 2008;Guiné et al, 2014). The equilibrium moisture contents near saturation, for a w ranging from 0.85 to 0.95, significantly increased: 19.8% at the beginning (0 day), 29.7% at 15 days, 35.1% at 40 days and 40% at 95 days.…”

“…1b), indicating a different ability of the product to bind water in this isotherm zone, probably because of water sorption by the starch-based components of the biscuit matrix (McMinn et al, 2007). These macromolecules are rich in polar sites that behave as active sorption centres (Guiné et al, 2014). It is well known that the behaviour and shape of the moisture sorption isotherms depend on the state of the system constituents ( Barbosa-Cánovas et al, 2007).…”

“…Most of them are aimed at evaluating moisture sorption characteristics of biscuits in relation to the effect of different temperatures (Arogba, 2001;McMinn, McKee, & Magee, 2007;Sampaio, Marcos, Moraes, & Perez, 2009) and/or of product brands and formulations (Guiné, Barroca, Pereira, & Correia, 2014;Palou, Lopez-Malo, & Argaiz, 1997) as well as in relation to the plasticization effect of water into the matrix (Martínez-Navarrete, Moraga, Talens, & Chiralt, 2004). In all of them the traditional gravimetric static method with saturated salts (DES) was used and different models to describe isotherms were applied.…”

Selecting packaging material for dry food products by trade‐off of sustainability and performance: A case study on cookies and milk powder

“…The cookies' moisture sorption isotherm is shown in Figure 1. The isotherm showed a type III shape, as classified by Brunauer et al 49 While type II isotherms are also reported for biscuits and cookies, this is a common finding for sugary confectionery products 13,50–53 . As discussed by Lewicki, 54 these curves possess inflexion points that indicate crucial moisture levels.…”

Shelf-life assessment of energy banana bar using acceleration method with critical moisture content approach

“…The accuracy of GAB modeling can be seen in Figure 2. GAB is expressed in accordance with several types of food such as biscuits, chicken wheat crips, and extrudate products (Bhardwaj et al, 2017;Guiné et al, 2014;Wani & Kumar, 2016). GAB model is known as a superior model because its success in modeling many food products in a wide "a w " range of 0.1-0.9 (Kurniawan, 2018;Bhardwaj et al, 2017).…”