Rheological Behaviour, Freezing Curve, and Density of Coffee Solutions at Temperatures Close to Freezing

Abstract

The physical properties of coffee solutions were determined for temperatures close to the freezing point. Rheological behaviour, freezing curve, density and their relationship between coffee mass fraction and brix degrees were determined for coffee mass fractions between 5 and 50% (wet basis) in the -6°C to 20°C temperature interval. Values of viscosity varied from 1.99 to 1037 mPa·s and values of density from 1000 to 1236 kg·m -3 . The freezing curve was generated using the undercooling method, giving values within freezing curves for food fluids. The results were used to generate mathematical models to predict viscosity, freezing point depression, and density as a function of coffee mass fraction and temperature.

Effect of falling‐film freeze concentration on bioactive compounds in aqueous coffee extract

“…The total soluble solids content of the solution was monitored every 30 min using an Atago refractometer (PAL‐BX/RI, Atago, Japan). °Brix measured in the samples were converted to a percentage of total solids using the equation: %Solids = 0.87% × °Brix, as reported by (Moreno, Quintanilla‐Carvajal, et al, ; Moreno, Raventós, et al, ). Each step was completed when the concentration index (CI) reached a range of 1.4–1.5.…”

“…In the food industry, the nutritional and sensory properties of the product may be affected by the processing of raw materials at high temperatures, as is the case for concentration by evaporation. Thus, freeze concentration (FC) has been implemented as an alternative in the food industry (Moreno, Quintanilla‐Carvajal, et al, ; Moreno, Raventós, et al, ; Sánchez, Ruiz, Auleda, Hernandez, & Raventos, ).…”

Freeze–thaw stability of emulsions with soy protein isolate through interfacial engineering

“…There are many potential applications for oil-in-water emulsions that can be frozen and then thawed prior to use, e.g. refrigerated and frozen food or pharmaceutical products (Moreno et al, 2015;Thanasukarn et al, 2006a). The freezing often adversely affects on the stability emulsion through various physical-chemical mechanisms, including water crystallization, freeze concentration, biopolymer conformational changes and interfacial phase transitions that these make the emulsions become unstable after thawing, which limits their use in food products (Dons et al, 2011;Ghosh and Coupland, 2008;Mun et al, 2008a).…”

Refractometric study on binary, ternary, and quaternary solutions made by water, methanol, ethanol, glycerol, D-glucose monohydrate (DGMH), sucrose, and sodium chloride at T = 293.15 K and atmospheric pressure

“…If the solution contains dissolved solids other than pure sucrose, then the °Bx only approximates the dissolved solid content. For aqueous solutions of sugars, there is a close relationship between the value of refractive index and its degree Brix [5][6][7]. The °Bx is usually used in the sugar, carbonated beverage, fruit juice, maple syrup and honey industries.…”