Manufacturers can up the antioxidant content in chocolate with a freeze dried raspberry leaf extract with minimal impact on texture and mouth-feel, according to a study.
Researchers enriched milk, semisweet and dark chocolate with concentrated (3% and 1%) and freeze dried (1%) red raspberry leaf extract and observed physical, sensory and bioactive changes compared to un-enriched samples.
Results were made available online ahead of publication in the journal Food Research International.
Freeze dried extracts retain mouthfeel
Draženka Komes et al. at the University of Zagreb, Croatia found that 3% concentrations were the best to raise the polyphenol content and antioxidant capacity, but concentrated extracts produced poor quality chocolate.
However, they said that chocolates formulated with freeze-dried extracts at 3% concentrations could boost polyphenols and antioxidants without significant changes in texture and flavour.
“Results indicate that the used concentrations of raspberry leaf extract are not effective enough for enhancing the bioactive profile of chocolates and that for achieving the optimal physical, bioactive and sensory properties a freeze dried concentrate of raspberry leaf should be used,“ concluded the researchers.
Chocolates with freeze-dried extract showed increased particle size, but the chocolate surface was practically unaltered. This formulation also scored the best in flavour, visual and textural properties compared to chocolates with concentrated extracts.
“The majority of functional chocolate products are based on the addition of polysaccharides or dietary fibers as fat replacers, various alternative sweeteners as sucrose replacers or the addition of probiotics,” said the researchers.
They said that few attempts had been made to produce chocolates with naturally-derived polyphenolic compounds and added that raspberry leaves possessed strong antioxidant properties and could be utilised in functional chocolate in as a freeze dried extract.
Food Research International (2012)
‘Innovative formulations of chocolates enriched with plant polyphenols from Rubus idaeus L. leaves and characterization of their physical, bioactive and sensory properties’
Authors: Belscak-Cvitanovic, A., Komes, D., Benkovic, M., Karlovic, S., Hecimovi´c, I., Jezek, D. & Bauman, I.