Valorization of cocoa pod side streams improves nutritional and sustainability aspects of chocolate.

Chocolate production faces nutritional, environmental and socio-economic challenges present in the conventional cocoa value chain. Here we developed an approach that addresses these challenges by repurposing the often-discarded pectin-rich cocoa pod endocarp and converting it into a gel. This is done using cocoa pulp juice concentrate to replace traditional sugar from sugar beets. Although swelling of fibres, proteins and starches can limit gel incorporation, our proposed chocolate formulation contains up to 20 wt% gel. It also has comparable sweet taste as traditional chocolate while offering improved nutritional value with higher fibre and reduced saturated fatty acid content. A cradle-to-factory life cycle assessment shows that large-scale production of this chocolate could reduce land use and global warming potential compared with average European dark chocolate production. The process also provides opportunities for diversification of farmers' income and technology transfer, offering potential socio-economic benefits for cocoa-producing regions.

Inkjet-based surface structuring: amplifying sweetness perception through additive manufacturing in foods.

Additive manufacturing (AM) is creating new possibilities for innovative tailoring of food properties through multiscale structuring. This research investigated a high-speed inkjet-based technique aimed to modify sweetness perception by creating dot patterns on chocolate surfaces. The dots were formulated from cocoa butter with emulsified water droplets containing the sweetener thaumatin. The number and surface arrangement of dots, which ranged from uniformly distributed patterns to concentrated configurations at the sample's center and periphery, were varied while maintaining a constant total amount of thaumatin per sample. A sensory panel evaluated sweetness perception at three consumption time points, reporting a significant increase when thaumatin was concentrated on the surface. Specifically, an amplification of sweetness perception by up to 300% was observed, irrespective of dot pattern or consumption time, when compared to samples where thaumatin was uniformly distributed throughout the bulk. However, when thaumatin was concentrated solely at the sample center, maximum sweetness perception decreased by 24%. Conclusively, both the proximity of thaumatin to taste receptors and its spatial distribution, governed by different dot arrangements, significantly influenced taste responsiveness. These findings present a more effective technique to substantially enhance sweetness perception compared to traditional manufacturing techniques. This method concurrently allows for sensorial and visual customization of products. The implications of this study are far-reaching, opening avenues for industrially relevant AM applications, and innovative approaches to study taste formation and perception during oral processing of foods.

Controlling lipid crystallization across multiple length scales by directed shear flow.

The crystallization behavior of lipids is relevant in many fields such as adipose tissue formation and regeneration, forensic investigations and food production. Using a lipid model system composed of triacylglycerols, we study the formation of crystalline structures under laminar shear flows across various length scales by polarized light-, scanning electron-, and atomic force microscopy, as well as laser diffraction spectroscopy. The shear rate during crystallization γ̇cryst influences the acyl-chain length structure and promotes domain growth into the flow direction thereby transforming the crystallites from oblate into prolate particles. Concentration dependent aggregation of crystallites into clusters is the rate limiting step for floc and floc network formation. At high γ̇cryst, fast crystallite cluster formation at smaller equilibrium diameters is promoted. The high crystallite cluster concentration induces their aggregation into flocs which form weak networks. At low γ̇cryst, floc generation is limited by the low amount of crystallite clusters leading to slow growth of larger flocs and forming of strong networks. The findings in this work have potential implications ranging from the design of injectable soft tissue fillers for adipose tissue regeneration, to the crystalline network formation in microorganism derived lipids, up to a more energy-efficient production of chocolate confectionery.

The rheology and foamability of crystal-melt suspensions composed of triacylglycerols.

The rheology of triacylglycerol (TAG) crystal-melt suspensions (CMSs) consisting of anhydrous milk fat (AMF), cocoa butter (CB), and palm kernel oil (PKO) as function of crystallization shear rate cryst and crystal volume fraction ΦSFC is investigated by in-line ultrasound velocity profiling - pressure difference (UVP-PD) rheometry. Measurements up to ΦSFC = 8.8% are presented. Below the percolation threshold Φc, no yield stress τ0 is observed and the viscosity η scales linearly with ΦSFC. Above Φc, a non-linear dependency of both τ0 and η as function of ΦSFC is apparent. For AMF and CB, the increase in cryst leads to a decrease in η and τ0 as function of ΦSFC, whereas for PKO based CMSs the opposite is the case. Scanning electron microscopy (SEM) and polarized light microscopy (PLM) relate these rheological findings to the microstructure of the investigated CMSs by taking the effective aspect ratio aeff and the concept of the effective crystal volume fraction ΦeffSFC into account. Foam formation by dynamically enhanced membrane foaming (DEMF) is performed directly after crystallization and reveals that depending on the CMS rheology and crystallite-, crystallite cluster- and crystal floc microstructure, a wide range of gas volume fractions between 0.05-0.6 are achievable.

Crystallization-Induced Network Formation of Tri- and Monopalmitin at the Middle-Chain Triglyceride Oil/Air Interface.

Crystalline glycerides play an important role in the formation of multiphase systems such as emulsions and foams. The stabilization of oil/water interfaces by glyceride crystals has been extensively studied compared to only few studies which have been dedicated to oil/air interfaces. This study investigates the crystallization and network formation of tripalmitin (TP) and monopalmitin (MP) at the middle-chain triglyceride (MCT) oil/air interface. TP crystals were found to crystallize in the bulk before aggregating as large rectangular crystal conglomerates at the MCT oil/air interface. This leads to the slow formation of a plastic deformable, macroscopic crystal layer with high interfacial rheological moduli. MP crystals form directly at the MCT oil/air interface resulting in a comparatively fast formation of an elastic deformable network. Crystals with tentacle-like morphology were found to be responsible for the network elasticity. In this work, we show how interfacial crystallization dynamics and mechanical strength can be linked to the molecular structure and crystallization behavior of glyceride crystals.