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Article
Effects of tempering and fat crystalization behaviours on microstructure, mechanical properties and appearance in dark chocolate systems.
Journal of Food Engineering (2008)
  • Emmanuel Ohene Afoakwa
  • Alistaiar Paterson
  • Mark Fowler
  • Joselio Vieira
Abstract

Fat crystallisation behaviours in dark chocolates from varying particle size distribution (PSD) (D90 of 18, 25, 35 and 50 µm) was studied, yielding products from different temper regimes (optimal temper, over-temper and under-temper), and their effects on mechanical properties and appearance evaluated. Microstructures of derived products were determined using stereoscopic binocular microscopy. Wide variations in mechanical properties and appearance were noted in products from different particle size and temper regimes. Particle size (PS) was inversely related with texture and colour, with the greatest effects noted in hardness, stickiness and lightness at all temper regimes. Over-tempering caused significant increases in product hardness, stickiness with reduced gloss and darkening of product surfaces. Under-tempering induced fat bloom in products with consequential quality defects on texture, colour and surface gloss. Micrographs revealed variations in surface and internal crystal network structure and inter-particle interactions among tempered, over-tempered and under-tempered (bloomed) samples. Under-tempering caused whitening of both surface and internal periphery of products with effects on texture and appearance. Thus, attainment of optimal temper regime during pre-crystallisation of dark chocolate was central to the desired texture and appearance as both over-tempering and under-tempering resulted in quality defects affecting mechanical properties and appearance of products.

Keywords
  • Chocolate,
  • Tempering,
  • fat crystallization,
  • Quality,
  • Cocoa,
  • Industry,
  • Confectionery
Publication Date
June 18, 2008
Citation Information
Emmanuel Ohene Afoakwa, Alistaiar Paterson, Mark Fowler and Joselio Vieira. "Effects of tempering and fat crystalization behaviours on microstructure, mechanical properties and appearance in dark chocolate systems." Journal of Food Engineering Vol. 89 Iss. 2008 (2008)
Available at: http://works.bepress.com/emmanueloheneafoakwa/85/