The effect of protein types and low molecular weight surfactants on spray drying of sugar-rich foods

Abstract

The effect of protein types and low molecular weight surfactants (LMS) on spray drying of sugar-rich foods has been studied using sucrose as a model sugar and sodium caseinate (NaCas) and pea protein isolate (PPI) as model proteins. Sodium stearoyl lactylate (SSL) and Polysorbate 80 (Tween-80) were chosen as model ionic and non-ionic LMS. The sucrose:NaCas and sucrose:PPI solid ratios were maintained at (99.5:0.5) and (99:1), respectively and spray-dried maintaining 25% solids in feed solutions. It was found that the proteins preferentially migrated to the airewater interface reasonably swiftly and the addition of LMS resulted into partial or complete displacement of the proteins from the airewater interface. More than 80% of amorphous sucrose powder was produced with the addition of 0.13% (w/w) of NaCas in feed solution. PPI was not as effective and produced less than 50% recovery even at 0.26% (w/w) in feed. Addition of 0.01e0.05% SSL displaced 2.0% and 29.3% of proteins from the surface of sucroseeNaCaseSSL droplet, respectively, resulting in a 6.5 AE 1.2% to 51.9 AE 1.9% reduction in powder recovery. The extent of protein displacement was higher when SSL was added into sucroseePPI solution; however, the powder recovery was not much affected. The addition of 0.01% Tween-80 in sucroseeNaCas solution resulted in a 48.2 AE 1.5% reduction in powder recovery and at 0.05% concentration, it displaced a substantial amount or all the NaCas from the droplet surface and no powder was recovered. The addition of 0.01% and 0.05% Tween-80 into sucroseePPI solution resulted into very low powder recoveries (24.9 AE 0.4% and 29.5 AE 1.8%, respectively). The glass transition temperature (T g) results revealed that the amount of protein required for successful spray drying of sucroseeprotein solutions depends on the amount of proteins present on the droplet surface but not on the bulk concentration. X-ray diffraction and scanning electron microscopy results showed that the powders of sucroseeNaCas/PPI and sucroseeNaCas/PPI with 0.01% SSL were mostly amorphous while those with sucroseeNaCas/PPIeTween-80 (0.01%), sucroseePPIeTween-80 (0.05%) and sucroseeNaCas/PPIeSSL (0.05%) were crystalline.

Surface protein coverage and its implications on spray-drying of model sugar-rich foods: Solubility, powder production and characterisation

“…The mixtures were mechanically stirred using a magnetic stirrer at 892 rpm for different time intervals (1, 3, 5, 10, 30 and 60 min). The dissolution kinetics was carried out on PPI based sugar powders, as PPI has a lower solubility than NaCas, to determine the effect of sugar on the solubility of protein (Jayasundera et al, 2011a). Pure protein samples were also subjected to dissolution kinetics for comparison.…”

“…An alternative and novel way to minimise the stickiness problem is to modify the surface properties of the droplets/particles with small amounts of proteins (Adhikari, Howes, Bhandari, & Langrish, 2009a;Jayasundera, Adhikari, Adhikari, & Aldred, 2010, 2011a. However, spray-drying can cause thermal denaturation of the proteins (Anandharamakrishnan, Rielly, & Stapley, 2008).…”

“…In our previous study we investigated the effect of low molecular weight surfactants and proteins on spray-drying of sugar rich foods and found that their presence greatly reduces the surface coverage of proteins (Jayasundera et al, 2010(Jayasundera et al, , 2011a. This means that the protein surface coverage of the droplets was minimised.…”

A continuum‐approach modeling of surface composition and ternary component distribution inside low fat milk emulsions during single droplet drying

“…The component transport inside the droplets was not primarily governed by DIMM (refer to sensitivity analysis in Section 4.3). The overrepresentation of protein at the surface was deemed to be due to its surface activity 17,42 . The prominent surface activity resulted in adsorption of protein molecules at the air/water interface, which increased its surface concentration 43,44 .…”

Optimizing spray drying conditions of sour cherry juice based on physicochemical properties, using response surface methodology (RSM)

“…As a result, during spray drying, much of the powder sticks to the chamber wall (Adhikari et al 2009a, b). Therefore, this kind of products cannot be dried without using any additive, so drying aids are used to produce fruit juice powder (Jayasundera et al 2011).…”