RELATIONSHIPS BETWEEN OPTICAL AND TEXTURAL PROPERTIES OF COLD-SET WHEY-PROTEIN GELS

The transition from a clear cold-set whey protein gel (10 mmol/L Ca2+) to a highly aggregated gel (360 mmol/L Ca2+) was studied using a fast responding fibre optic probe. The gels, formed at room temperature by gradually increasing [Ca2+], showed a progressive increase in gel str ength measured as penetration force. Fibre optic probe results correla ted highly with gel strength data, whereas a conventional surface colo ur meter was not as useful. The gels' ability to deform (spread oat du ring compression) decreased with the increase in [Ca2+] and correlated with the probe readings; the surface colour meter provided an r = 0.6 3. The specific design of the probe that made it sensitive to scatteri ng light was used to explain the differences between the two light mea suring apparatuses. Overall, the probe allowed a rapid assessment of t he characteristics of cold-set whey protein gel. (C) 1997 Academic Pre ss Limited.