Experimental study of physical and rheological properties of grape juice using different temperatures and concentrations. Part II: Merlot

Abstract

The effect of the temperature and concentration on rheological behavior of Merlot juice concentrates was assessed using a rheometer over a wide range of temperature (1-66°C) and concentrations (13.6-45.0Brix) at shear rates of 0.84-212.1 1/s. The Ostwald-De Waele was the best rheological model fitted the data (R=0.99967 and relative error=7.99%). The consistency levels were significantly reduced with the increase of temperature and increased with the increase of the concentrations, ranging from 0.1766 (13.6Brix at 66°C) to 19.1140Pa·s (45.0Brix at 1°C). The flow behavior index presented no up or downward pattern when the temperatures were compared. The flow activation energy ranged from 13.95 (45.0Brix) to 24.88KJ/mol (21.0Brix) with a R=0.9822 and 0.9812, respectively. Density and specific heat were influenced by both temperature and concentration; however, thermal conductivity was only influenced by concentration and temperature in two cases (13.6 and 29.0Brix). The data showed the potential use of Merlot juice concentrates as wine chaptalization agent in winemaking.

Effect of sodium sulfite, tartaric acid, tannin, and glucose on rheological properties, release of aroma compounds, and color characteristics of red wine

“…All the values of flow behavior index (n) were less than 1 which proved the shear-thinning and non-Newtonian behavior of the red wine samples (Trávníček et al, 2016). Our results concerning the non-Newtonian pseudoplastic behavior of red wine samples agreed with the previous studies (De Castilhos et al, 2018). Higher K value indicated the higher apparent viscosity.…”

Thermophysical properties of carbohydrate solutions: Correlation between thermal and transport properties

“…Regarding the temperature, Figure 2(d)-(f) also showed that specific heat slightly increases with increasing temperature. This same trend was noticed for Cabernet Sauvignon grape juice (Castilhos et al, 2017), Merlot grape juice (Castilhos et al, 2018), juices and syrups from a noncentrifugal sugar cane production process (Alarcón et al, 2020), meat extract (Polachini, Betiol, Bastos, Telis, & Telis-Romero, 2017), pequi pulp (Souza, Queiroz, Figueirêdo, Santos, & Lemos, 2016) and papaya puree (Tansakul, Kantrong, Saengrayup, & Sura, 2012). So, it could be assumed that diluted solutions demand more energy to increase the temperature than concentrated solutions with the same mass.…”

“…The experimental data of sucrose, glucose and fructose solutions were very similar (maximum deviation of 3%) to that observed by Darros-Barbosa et al 2003 On the other hand, the same Figure (2a-c) showed that density was inversely proportional to the temperature: it increased as the temperature decreased. The same behavior is observed for different products, such as grape juice Merlot (Castilhos et al, 2018), meat extract (Polachini et al, 2016), Malay Rose apple pulp (Fontan et al, 2018), juices and syrups from a noncentrifugal sugar cane production process (Alarcón, Orjuela, Narvaéz, & Camacho, 2020) and…”

“…Their accurate determination provides reliable data for understanding and designing heat transfer processes. Techniques as differential scanning calorimetry (DSC) have been proven to be very accurate in determining specific heat of food products (Castilhos, Betiol, Carvalho, & Telis-Romero, 2018;Leila et al, 2019;Parniakova et al, 2018). Systems properly designed with electrical resistance and metallic cell also demonstrated to be useful and accurate for determining thermal conductivity (Costa, Silva, & Vieira, 2019), while thermal diffusivity can be easily obtained by correlating the aforementioned properties.…”

Effect of lyophilization on the rheological properties of squash (Cucurbita moschata) and sesame (Sesamun indicum) cream

“…This behavior is rationed with the food processing conditions, whether thermal and non-thermal processes, affect the natural structure and the composition of food powders; the structure of foods can have a profound influence on its nutritional value, rheology and functional attributes [24]. The rheological behavior of a fluid is influenced by several factors, mainly the intermolecular forces and the water-solute interaction which limit the movement of the particles at a molecular level [25]. Changes in the temperature and concentration can lead to significant changes in the intermolecular forces [26].…”