Effects of types and ratios of Emulsifiers and ratios of Milk permeate on the sensory and antioxidant properties of Dark chocolate containing Cocoa shells powder

Abstract

This study aimed to evaluate effects of types and ratios of emulsifiers and ratios of milk permeate in making dark chocolate containing cocoa bean shells. Dark chocolate samples were made with different types and ratios of emulsifiers including soy lecithin (0.5%; 1%; 1.5%) , polyglycerol polyricinoleate (0.1%; 0.3%; 0.5%), and xanthan gum (0.4%; 0.6%; 0.8%), and different ratios of milk permeate varying from 5% to 25% (weight of milk permeate/ total weight of chocolate sample). In this study, total phenolic content (TPC) total flavonoid content (TFC), antioxidant scavenging capacity (AC) and sensory attributes of dark chocolate containing cocoa bean shells were evaluated. Furthermore, hardness and color measurements were investigated to examine the stability of dark chocolate containing cocoa bean shells at two different temperatures (40C and room temperature) over a storage period of 3 weeks. Overall, the use of 0.5% soy lecithin in chocolate production results in total phenolic content (5.82 ± 0.08 mg gallic acid GAE/g chocolate) and antioxidant capacity. (48.98 ± 0.33%) is significantly higher than the value for dark chocolate without emulsifiers (5.28 ± 0.13 mg gallic acid GAE/g chocolate and 36.73 ± 0.23% respectively) while sensory evaluation showed no significant differences in all sensory attributes between samples. Besides, application of 5% milk permeate on dark chocolate containing cocoa bean shell with 0.5% soy lecithin resulted in higher total phenolic content (8.18 ± 0.06 mg gallic acid GAE/g of chocolate), total flavonoid content (20.25 ± 0.91 mg rutin RTE/g of chocolate) and antioxidant capacity (46.96 ± 0.46%) when compared to the other sample varying 10% to 25%. In addition, after 3-week storage duration, the sensory test showed significant difference for almost attributes among samples. Further, color of samples stored at room temperature were whiter than that of 4oC while its texture became softer at room temperature. On the other hand, the higher ratio of milk permeate may soften the texture of the dark chocolate sample due to fat migration.