Particle stability in dilute fermented dairy drinks: formation of fluid gel and impact on rheological properties.

Fluid gels are known to be very shear-thinning materials with yield stress. In this study, the rheological properties of gellan and gellan-pectin fluid gels in fermented dairy drinks were evaluated using viscometric measurements. Both gellan- and gellan-pectin-containing solutions showed the rheological properties of fluid gels resulting in stabilization of particles; but no evidence of a fluid gel was observed for those with pectin alone and those with no hydrocolloid content. Unlike pectin, gellan gum was capable of creating significant values of yield stress and accordingly stabilized colloidal particles and extrinsic added solid particles in the fermented dairy drink. However, pectin improved the stability in combination with gellan. The origin of fluid gel formation was assumed to be both permanent interactions occurring between gellan and proteins, forming hairy particle gels and transient interactions between the particle gels. The significance of yield stress values for particle stability was demonstrated and two methods, including a noteworthy infinite apparent viscosity method and a conventional Bingham approach, were employed to calculate the values of yield stress. Both the methods showed a good application potential due to their simplicity, reasonable results and also wide availability of the instrument applied.

Technical notes published in BJOMS over a 2-year period--should we be doing it differently?

Between January 2007 and December 2008, 44 technical notes or related publications (such as letters) were published in the British Journal of Oral and Maxillofacial Surgery (BJOMS). These covered most of the remit of the specialty and ranged from operative surgical techniques to the use of digital photographs to orientate surgical specimens. However, there would seem to be very little feedback on the value of these articles in everyday practice. We reviewed these technical notes and assessed readability, the value and use of illustrations, the possible expense and/or equipment required in their use, and finally the frequency that the techniques could be used. The anonymised publications were read and scored by a minimum of two dentally qualified senior house officers, two doubly qualified specialist registrars, an SAS grade and two consultants in oral and maxillofacial surgery. The six techniques that gained the highest mean average score are briefly discussed. Although we used a relatively small number of assessors who might not be representative of the whole BJOMS readership, this study would suggest that some sort of change in the way that these technical notes are published should be considered. Options might include inviting a commentary from the reviewers who have tried the technique and also encouraging colleagues to report their experiences of these techniques in the 'letters to the editor' section.