Does High Voltage Electrical Discharge Treatment Induce Changes in Tannin and Fiber Properties of Cocoa Shell?

Abstract

Cocoa shell is a by-product of the chocolate industry that is rich in dietary fiber and bioactive components. In this research, the influence of high voltage electric discharge (HVED) treatment on chemical and physical characteristics of the cocoa shell, i.e., the effects of applied time and frequencies on grinding ability, water binding capacity (WBC), dietary fibers and tannin content was investigated. HVED had a significant influence on the chemical and physical properties of cocoa shell, all of which could be linked to changes in fiber properties. Along with the fiber content, grinding ability and water binding capacity were increased. These properties have already been linked to fiber content and soluble/insoluble fiber ratio. However, this research implies that change in fiber properties could be linked to tannin formation via complexation of other polyphenolic components. Additional research is needed to verify this effect and to establish mechanisms of tannin formation induced by HVED and its influence on fiber quantification.

Physical Properties of Chocolates Enriched with Untreated Cocoa Bean Shells and Cocoa Bean Shells Treated with High-Voltage Electrical Discharge

“…While the The results also show that the dark and milk chocolate samples with HVED-treated cocoa shells had larger particles than the chocolates with untreated cocoa shells. This is in accordance with our previous research [13], where we showed that cocoa shells treated with HVED were harder to grind. According to Konar et al [22], particle size distribution inversely affects the hardness of chocolate because of the particle-particle interactions.…”

“…In addition, chocolates with untreated cocoa shells had lower viscosities than those with HVED-treated shells. In our previous study, it was shown that treated cocoa shells had a higher oil-binding capacity than untreated ones [13]. Bolenz et al [14] stated that wheat fibers and cellulose can absorb oil, which leads to a reduced continuous fat phase.…”

Cocoa Shell as a Step Forward to Functional Chocolates—Bioactive Components in Chocolates with Different Composition

“…Another component influencing polyphenol behavior in food systems is fiber. In our previous researches we treated cocoa shell with HVED and explored its influence on polyphenols [ 25 ] and fiber [ 26 ]. HVED reduced contents of all analyzed polyphenolic components and increased content of insoluble fiber, which was reflected in properties of chocolates in this research.…”

“…In addition to fiber content, porosity and surface properties of fiber, as well as molecular weight of polyphenols and polyphenol-protein complexes influence these interactions [ 19 ]. After HVED treatment, both oil- and water-binding capacities of cocoa shell increased [ 26 ], indicating that HVED could result in a more porous structure of fiber. The pores could entrap polyphenols not only from cocoa shell, but from cocoa mass as well, making them inaccessible for extraction and determination.…”

“…(−)-Epicatechin is well described in regarding antioxidant properties and reactions involved [ 27 ], with more pronounced activity in non-polar media, such as fats (hence, chocolate is a product with high cocoa butter content) [ 24 ]. It even interferes with Maillard reactions, quenching sugar fragmentation products [ 28 ], could undergo epimerization reactions and finally condensation into tannins also interact with proteins [ 26 ]. (+)-Catechin is very similar in properties to (−)-epicatechin and this is the main reason why they show similar behavior in this research as well.…”