Rheological behavior of molasses for application in industry

Abstract

Molasses is a by-product from the raw sugarcane industry with vast applications in the production of ethanol biofuel. A good knowledge of the rheological properties of this raw material is of crucial importance when designing and optimizing unit operations involved in processing it. The present work thus aims to study the rheological behavior of molasses at solid concentrations ranging from 20 to 70 o Brix and temperatures between 21 and 988C using a concentriccylinder rheometer. Experimental results showed Newtonian behavior in concentrations of 20 and 40 o Brix and pseudoplastic behavior in concentrations of 50 and 70 o Brix. For these results, the Power Law models presented the best fitting results. In addition, the dependence of the flow behavior index and the flow consistency index of the Power Law model on temperature and solid concentration was also successfully modeled through a polynomial model and an Arrhenius-type equation, respectively.

Rheological behavior of different phases of grape molasses after storage: Effect of concentration and temperature

“…Quek et al () also addressed that the power law model was the best one to describe the rheological data of soursop juice concentrates. Similar results were observed in other studies regarding sugarcane molasses (Cristina dos Santos Bofo et al, ), poppy seed paste/grape pekmez blends (Özkal & Süren, ), and aloe vera juice concentrates (Swami‐Hulle, Patruni, & Rao, ). Moreover, the rheological behavior of sorghum pekmez was described by the power low model (Akbult & Özcan, ).…”

“…This means that the rheological behavior of the samples (both red and brown phases) was similar to a non‐Newtonian fluid. Similar findings were reported by Alpaslan and Hayta () for tahin/pekmez blends in the temperature range of 30–75°C and pekmez concentrations of 2–6% (w/w), Arslan et al () for pekmez (grape molasses)/tahin (sesame paste) blends in the temperature range of 35–60°C, tahin concentrations of 20–32% (w/w), Cristina dos Santos Bofo et al () for sugarcane molasses in the temperature range of 21–98°C, and concentrations of 50–70°Brix, Quek et al () for soursop juice concentrates in the temperature range of 10–70°C, concentrations of 10–50°Brix, Karaman and Kayacier () for apricot and date molasses in the temperature range of 10–40°C, Özkal and Süren () for poppy seed paste/grape pekmez blends, Sengül, Ertugay, & Sengül () for mulberry pekmez in the temperature range of 30–70°C, and Swami‐Hulle, Patruni, & Rao () for aloe vera juice concentrates in the temperature range of 15–55°C and concentrations of 1.5–5.5°Brix.…”

“…The calculation of the activation energy ( E a ) was based on an Arrhenius form of equation. Therefore, using Equation (3), the K parameter was associated with the temperature as follows (Cristina dos Santos Bofo et al, ; Deshmukh et al, ):…”

“…In order to describe the flow behavior and/or deformation of foodstuffs, the experimental data obtained from the rheological tests are fitted to different rheological models such as Newtonian equation, power law (Oswald–deWaelle) model, Bingham equation, Casson model, and Herschel–Bulkley model (Cristina dos Santos Bofo et al, ; Quek, Chin, & Yusof, ). Rheological parameters of models such as consistency coefficient or consistency index ( K ), yield stress ( σ 0 ), and flow behavior index ( n ) can be used to determine the type of the rheological behavior of the studied fluid foodstuff.…”

“…Rheological characteristics of foods are dependent on both the initial materials properties (such as initial soluble solids, particle size, and added thickening substances) and processing conditions (such as temperature and levels of shear rate) (Karaman & Kayacier, ; Quek et al, ; Toker & Dogan, ). Among these, concentration and temperature have been shown to be the most important factors affecting the rheological behavior of food product (Cristina dos Santos Bofo et al, ; Deshmukh, Manjunatha, & Raju, ; Quek et al, ).…”