Determination of Physical Properties and Crystallization Kinetics of Oil From Allanblackia Seeds and Shea Nuts Under Different Thermal Conditions

Abstract

In this study, the fatty acid content, melting and cooling profiles, crystallization properties at different cooling rates and kinetics of crystallization of Allanblackia seed oil (ASO) and shea nut oil (SNO) are investigated. The fatty acid content is determined using gas chromatography coupled with mass spectrometry (GC/MS). The melting and cooling profiles, crystallization, and crystallization kinetics are investigated using differential scanning calorimetry (DSC) and the fat morphology is investigated using polarized light microscopy. The GC/MS results showed that ASO contains a high amount of saturated fats as compared with SNO. The DSC analysis revealed that ASO has a high melting temperature of 35.3 ± 2.1 °C and crystallizes earlier (16.8 ± 0.3 °C) in the constant rate cooling experiments. The crystallization patterns of both oils are observed to be dependent on the cooling rate. Under isothermal conditions, it is observed that both ASO and SNO shows high and low melting peaks with the low melting peak disappearing as the crystallization progressed. The Avrami model is used to estimate the crystallization kinetics of the oils under the isothermal conditions and it is inferred that ASO has a faster nucleation and subsequent crystal growth as compared with SNO. At room temperature SNO formed overlapping fat crystal particles while ASO gave distinct crystallized fat fractions during the crystallization at room temperature, as shown by the polarized light microscopy. Practical Application: The high melting temperature, the rate and the nature of crystallization of Allanblackia seed oil gives it good material functionality and desired plasticity, properties associated with possible industrial application. Additionally, the presence of high stearic acid content makes the Allanblackia seed oil a healthy choice for food, hence, it can be used as a substitute for cocoa butter in the food industry. The appearance of fat crystals during the crystallization at isothermal conditions at 16 °C of the Allanblackia seed oil.

Kinetics Crystallization and Polymorphism of Cocoa Butter throughout the Spontaneous Fermentation Process

“…On the other hand, decimal values of indicate that both forms of crystal growth can co-occur, either sporadically or instantaneously. In the study carried out by Badu et al [ 1 ], small values of were obtained for Allanblackia seed oil and shea nut oil, which indicates their rapid nucleation and crystallization mechanism. The crystallization rate constant, , of CB was higher than that of POP and increased with ; therefore, its crystallization is faster.…”

“…Cocoa butter (CB) is a natural fat extracted from cocoa beans [ 1 ]. CB has a crystalline structure that determines the final quality of chocolate [ 2 , 3 ].…”

“…The most used method to describe the behavior of cocoa butter is the Avrami model, which describes the kinetics of crystallization and crystal growth [ 1 , 32 , 33 ]. Avrami’s equation describes an initial period where crystallization occurs slowly and is followed by a rapid increase in the mass of the crystal formed.…”

Process Analysis of Shea Butter Solvent Fractionation Using a Generic Systematic Approach

“…There is a vast literature were various experimental studies for oil and fats crystallization with focus on specific binary or multicomponent systems are conducted, but limited data can be found for shea oils and its products 14,[42][43][44] . Regarding the modelling aspects, several models for solidliquid equilibria modelling [45][46][47] , simple crystallization kinetics 48,49 (e.g.…”

Physical Chemical Properties of Shea/Cocoa Butter Blends and their Potential for Chocolate Manufacture

“…Several authors have reported the physical chemical properties of SB or its fractions. Badu et al () compared the physical properties and crystallization behavior of shea nuts and allanblackia seeds oils under different thermal conditions. Those results showed that the thermal behavior, crystallization mechanism, and crystal structure were strongly dependent on fatty acid (FA) composition of oils.…”