Blooming reduces the antioxidant capacity of dark chocolate in rats without lowering its capacity to improve lipid profiles

Nutr Res. 2013 May;33(5):414-21. doi: 10.1016/j.nutres.2013.03.004. Epub 2013 Apr 13.


Dark chocolate contains high levels of antioxidants which are linked to a reduced risk of cardiovascular disease. Chocolate blooming occurs after exposure to high temperatures. Although bloomed chocolate is safe for human consumption, it is not known whether or not the biological function of bloomed chocolate is affected. We hypothesized that bloomed chocolate would reduce the antioxidant potential and lipid-lowering properties of chocolate through altered expression of related genes. Thirty Sprague-Dawley rats were divided into 3 groups and fed either the control (CON), regular dark chocolate (RDC), or bloomed dark chocolate (BDC) diet. After 3 weeks, serum lipid levels and antioxidant capacity were measured. Hepatic expression of key genes was determined by real time polymerase chain reaction (PCR). Sensory characteristics of bloomed versus regular chocolate were assessed in 28 semi-trained panelists. Rats fed RDC exhibited greater serum antioxidant capacities compared to the CON (P < .05). Antioxidant levels of BDC were not different from RDC or CON. Both RDC and BDC lowered TG compared to CON (P < .05). The rats fed RDC had higher high-density lipoprotein levels compared to the CON (P < .05). In rats given RDC, fatty acid synthase gene expression was down-regulated and low-density lipoprotein receptor transcription was up-regulated (P < .05). Sensory panelists preferred the appearance and surface smoothness of the regular chocolate compared to bloomed chocolate (P < .001). Although blooming blunted the robust antioxidant response produced by regular dark chocolate, these results suggest that bloomed dark chocolate yields similarly beneficial effects on most blood lipid parameters or biomarkers. However, regular dark chocolate may be more beneficial for the improvement of antioxidant status and modulation of gene expression involved in lipid metabolism and promoted greater sensory ratings.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology*
  • Biomarkers / blood
  • Cacao / chemistry*
  • Candy*
  • Down-Regulation
  • Fatty Acid Synthases / genetics
  • Fatty Acid Synthases / metabolism
  • Humans
  • Lipid Metabolism / drug effects
  • Lipoproteins, HDL / blood*
  • Lipoproteins, LDL / blood*
  • Liver / drug effects
  • Liver / metabolism
  • Male
  • Odorants / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, LDL / genetics
  • Receptors, LDL / metabolism
  • Taste
  • Up-Regulation


  • Antioxidants
  • Biomarkers
  • Lipoproteins, HDL
  • Lipoproteins, LDL
  • Receptors, LDL
  • Fatty Acid Synthases