Moisture Sorption Characteristics of Dakuwa (Nigerian Cereal/Groundnut Snack)

Abstract

The moisture sorption characteristics of dakuwa at 10, 20, 30 and 400°C were studied. The experimental sorption data obtained were applied to BET, GAB, Oswin and Henderson equations to test fitness of the equations to moisture sorption of dakuwa. The sorption isotherms of dakuwa were type III isotherms (J shaped), and the equilibrium moisture content increased with increasing water activity but decreased with increasing temperature. The BET and GAB monolayer moisture contents all decreased with increasing temperature. For adsorption, the BET monolayer was higher (3.163–4.158 g/100 g solid) than that of GAB (2.931–3.728 g/100 g solid), but for desorption, the GAB monolayer (4.792–7.741 g/100 g solid) was higher than that of BET (3.962–4.480 g/100 g solid). Evaluation of goodness of fit of models revealed that moisture sorption of dakuwa was best modelled by GAB equation.

Moisture sorption properties of two varieties of dehydrated mango slices as determined by gravimetric method using Guggenheim–Anderson–de Boer model

“…With an increase in temperature, water molecules are imparted with an elevated state of excitation that in turn decreases attractive forces between them and increases their distance resulting in decreased degree of water sorption with increased temperature at a given state of relative humidity. This has an implication that increased temperatures results in decreased hygroscopic nature for the product (Ocheme et al, 2013). According to Ariahu et al.…”

“…With an increase in temperature, water molecules are imparted with an elevated state of excitation that in turn decreases attractive forces between them and increases their distance resulting in decreased degree of water sorption with increased temperature at a given state of relative humidity. This has an implication that increased temperatures results in decreased hygroscopic nature for the product (Ocheme et al, 2013). According to Ariahu et al (2006), at a fixed moisture content, increased a w at elevated temperatures rendered products more easily susceptible to microbial deterioration since the water activity occur at a point above critical levels estimated for safe storage.…”

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“…Basically, in the packaged samples, more moisture is present in the sample as these microbes increase and the temperature fluctuates whereas in the unpackaged samples, moisture is constantly lost. These microbes also produce alcohol and water as their by-products, the water also adds on to the quantity on water already available in the samples, thereby attributing to the increase of moisture after it has reduced or been used up by these microbes [7].…”

“…Production varies with people, culture and geographical locations: these leads to possession of variable characteristics [6]. Some of the problems associated with the local production of snacks such as dakua include non-standardization of equipment, process and raw material, inadequate hygiene during and after production, and little or no packaging which results in poor preservation techniques and high levels of contaminants in the food resulting in food borne illnesses [7].…”

Effects of Groundnut (Arachis Hypogea L) Varieties on the Flavour Profile and Consumer Acceptability of Dakuwa (A Cereal-Groundnut Based Snack)

“…The cereal can also be partially replaced by tigernut (Oladele et al 2009). The ingredients are thoroughly mixed, pounded and molded into balls that can be eaten without further processing (Abdulrahaman and Kolawole, 2003;Ocheme et al, 2013). The acceptability of Dakuwa by consumers is dependent on many factors including its taste, colour, texture and flavour (Ocheme et al, 2011).…”