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Consumer Acceptance of Whey-protein-coated Versus Shellac-coated Chocolates
By,
S.-Y.LEE, K.L. Dangaran, J.-X.Guinard and
J.M.Krochta
Department of Food Science & Technology
University of California, Davis
Shellac, also known as confectioner's glaze, is used for the final glazing step of a chocolate manufacturing process. Although shellac provides desirable gloss and a good moisture barrier, there also are disadvantages in using shellac. Shellac is solubilized in alcohols which are miscible with the fats and oils contained in chocolate. This may cause off-flavors which are not desirable. Using alcohol as solvent can also produce volatile organic compounds (VOCs) which are hazardous to the environment. Another disadvantage to using alcohol-based shellac is a potential explosion hazard during processing. The development of aqueous film coatings will reduce off-flavors, VOCs, dependence on operator experience and processing times.
The objectives of this study were, first, to develop a glaze using an aqueous coating formulation with whey-protein-isolate (WPI) which can be used in the chocolate manufacturing process, and second, to investigate the consumer acceptance of the various WPI-coating formulations versus shellac coating.
Four different formulations of WPI-coatings were used to coat the chocolates. There were two formulations without lipid and two with lipid. The two WPI formulations with no lipid varied in native vs. heat-denatured WPI amount. The two WPI formulations with lipid varied in the lipid amount. The shellac formulation consisted of 30% solids, of which 90% was shellac and 10% was propylene glycol used as a plasticizer. A central location consumer test was carried out for overall degree of liking and degree of liking for taste, texture in the mouth, overall appearance, surface texture in appearance and gloss.
Consumer study results revealed that there was a significantly higher consumer acceptance for the WPI formulations with lipid over shellac, followed by WPI formulations without lipid.
The results strongly suggest that water-based WPI-lipid coatings can be used as an alternative glaze with higher consumer acceptance than alcohol-based shellac regarding various sensory attributes.
For more information on Dr. Krochta’s work and the Food Science and Technology Department at UC Davis, please visit Dr. Krochta's Web site - http://foodscience.ucdavis.edu/fst/faculty/KrochtaWeb/index.htm.