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Rheological Properties of Aloe Vera ( A loe barbadensis Miller) Juice Concentrates
Author(s) -
Swami Hulle Nishant R.,
Patruni Kiran,
Rao P. Srinivasa
Publication year - 2014
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/jfpe.12093
Subject(s) - aloe vera , chemistry , rheology , fourier transform infrared spectroscopy , arrhenius equation , viscoelasticity , viscosity , shear rate , chromatography , activation energy , analytical chemistry (journal) , materials science , chemical engineering , organic chemistry , composite material , botany , engineering , biology
Flow characteristics of aloe vera juice concentrates (1.5–5.5° B rix) were determined over a range of temperatures (15–55 C ) by using coaxial cylinder geometry. Aloe vera juice exhibited non‐ N ewtonian fluid behavior which was well described by power law model. Functional groups were characterized by F ourier‐transform infrared ( FTIR ) spectroscopy indicating the presence of O ‐acetyl and shifting of – CH bonds. Effect of test temperatures at different shear rates on viscosity was evaluated using Arrhenius‐type equation and the activation energy values were evaluated which ranged between 12.148 and 53.073 kJ /mol. Effect of concentration was evaluated using power type and exponential type equations. An expression for combined effect of temperature and concentration was developed. Small amplitude oscillation sweep measurement was also carried out and the frequency sweep test exhibited viscoelastic nature of juice. Practical Applications Aloe vera is commercially very important crop and is being used in food, medicines and cosmetics. Rheological properties are important parameters and are used to assess the functional and structural properties of food products. In this study, the flow and deformation characteristics of aloe vera juice concentrates were evaluated as a function of temperature and concentration. An expression for the combined effect of concentration and temperature on the viscosity was evaluated. Oscillatory sweep experiments can be used to assess the viscoelastic properties, which are useful to develop the products of desired functionalities. The changes in functional groups due to concentration can be assessed using FTIR spectroscopy analysis.