Templating effects of dipalmitin on soft palm mid-fraction crystals

ABSTRACT

The crystallization of lipids has important implications for the industrial processing of food products, such as chocolates, margarines, spreads, confectionery, as well as bakery and dairy products. Thus, blends of soft palm mid-fraction (PMF) and dipalmitin (PP) containing PP of 0.5 g/100 g and 1.0 g/100 g were investigated under stabilization time and conditions for controlling and improving the crystallization step of fat during fat modulation. Crystallization results showed by reducing the Avrami parameters t_sfc, t_1/2, and k, the addition of PP accelerated the crystallization process of PMF. Changes in the crystals morphology observed by polarized light microscopy gave a higher crystallized area and reduced crystals size in the microstructure of the PMF, which was also verified by the increase in melting point and solid fat content (SFC). The addition of PP caused changes in the arrangement of the PMF triacylglycerols (TAGs), by stabilizing the β´stable polymorphic form, thereafter stabilizing the melting profile and the consistency of PMF over time. These results have interesting implications in the fat and oil industry as they allow for the marketing of products with improved crystallization properties and the stabilization of more stable polymorphic forms, expanding the range of applications of slow-crystallizing fats.

KEYWORDS:

• Soft palm mid-fraction
• Dipalmitin
• Crystallization
• Polymorphism
• Thermal behavior

Conclusion

This study showed that the addition of PP changes the arrangement form of soft PMF’s TAGs, causing drastic changes in the crystal lattice structure and the solidification properties of soft PMF. Such structural changes in turn accelerate the crystallization process owing to a faster stabilization of the polymorph of interest. The changes occurring during the crystallization process of the PMF/PP blend can be summarized as follows: (i) PP is highly soluble in liquid PMF but its solubility decreases with supercooling owing to the presence of long-chain palmitic acid, (ii) PP crystallizes prior to the PMF’s TAGs and acts as a template for PMF crystals, (iii) PP accelerates the rearrangement of the PMF’s TAGs from the melted state and assists in the formation of stable β’ crystals. Such changes in the crystallization process of soft PMF represent a highly viable option, in terms of economy and technology, for modulating the crystallization properties of special fats in the food industry.

Funding

The authors are grateful for the financial support received from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP—Proc. 2009/53006-0 and Proc. 2012/10871-6) and Conselho Nacional de Pesquisa (CNPq).

Supplemental data

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

The authors are grateful for the financial support received from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP—Proc. 2009/53006-0 and Proc. 2012/10871-6) and Conselho Nacional de Pesquisa (CNPq).