Characterisation of the Wetting Behaviour of Poor Wetting Food Powders and the Influence of Temperature and Film Formation

Abstract

Characterisation of the wettability of five poor wetting food powders was performed using static immersion and contact angle measurements. The effect of temperature (20, 50 and 70 °C) on wettability showed varying effects on the powders. Higher temperatures majorly improved the wettability of chocolate and high fat powders but worsened the wettability of sodium caseinate and milk protein isolate. Rate-limiting regime testing was performed by pouring a fixed mass of powder on to the surface of water in an agitated beaker and visually assessing what was rate-limiting rehydration after 1 minute. The rate limiting regime tended to be floating at lower agitation speeds and dispersed clumps of varying sizes at higher speeds. However, there were major differences observed between the powders. Some of the powders formed strong films at powder/water interfaces, that could act as a barrier to water penetration and wettability. Consequently, force displacement testing was performed on a layer of powder on the water surface to assess the strength of any powder film formed. Some of the powders formed strong films that may in-part explain their poor wetting behaviour and their propensity to form strong clumps that were difficult to disrupt.

The effect of microparticulated whey protein on the characteristics of reduced‐fat cheese and of the corresponding microwave vacuum‐dried cheese puffs and finely ground puffs

“…Fitzpatrick et al . (2017) showed that increasing water temperature improved wettability; for example, skimmed milk powder (132 µm) presented a wettability value of 51 s at 20 °C, 16 s at 50 °C and 10 s at 70 °C. In this, similar research results (at 35 °C) were obtained (7 s for ground puffs A and 9 s for ground puffs B) without significant differences between them ( P > 0.05).…”

Studies on flow properties of Bengal gram (Cicer arietinum) flour for effective handling and storage strategies

“…The high protein increases the protein-protein interaction between the particles which resist the movement of water into particle (Silva & O'Mahony, 2017). In some studies, it was found that how the composition of food powders majorly influences the wettability, that is, the high amount of fat present in food powders provides poorest wettability to powders due to the hydrophobic nature of fat (Fitzpatrick, Salmon, Ji, & Miao, 2017). Similar study by Crowley et al (2015) found that the contact angle of milk protein concentrate increases with larger particle size and higher protein content of the milk powder.…”

Rehydration Properties of Whey Protein Isolate Powders Containing Nanoparticulated Proteins

“…The wettability of WPI powders was measured gravimetrically using a modified immersional wetting approach [28,29]. Powder samples were poured onto ultrapure water and allowed to wet and sink for 1 h. Powder that remained on the water surface was carefully removed with a spoon, weighted and dried overnight at 105 °C.…”