Use of ohmic heating during the fermentation of cocoa beans.
The fermentation of cocoa beans is one of the most critical stages of the entire chocolate production process, as it determines the final product quality. In general, conventional fermentation in wooden boxes takes 6-8 days. However, the long duration of the process and the absence of controls lead to a decrease in product quality.
Therefore, as a more effective alternative, in a recent study carried out by a group of Indonesian researchers (Putranto et al., 2023), the use of ohmic heating during the fermentation of cocoa beans was proposed. In particular, for testing, a reactor was designed and built to conduct the process, assessing its effects on the physical, chemical and biological characteristics of the product.
In addition, the samples thus obtained were compared with those prepared with the traditional treatment in wooden boxes. The results show that the ohmic reactor can ferment beans more completely (99.97% samples fully fermented at the end of the process compared to 77.33% in case of fermentation in wooden crates) in a much shorter time (3 days) than the conventional process.
Although the operating costs of ohmic processing are higher than those of traditional processing, the product thus obtained can be sold at a higher price, generating a higher income. In conclusion, further analysis is needed to evaluate in detail the scale-up of the reactor developed for medium and large-scale production applications.
The effect of roasting cocoa beans with microwaves on the quality of dark chocolate.
The objective of a recent study, carried out by a team of Belgian researchers (Schouteten et al., 2023), was to assess the effect of an alternative cocoa roasting process, based on the use of microwaves, on the main physical and sensory characteristics of dark chocolate (70%).
Samples prepared with beans treated at 600 W for 35 minutes were compared with those obtained with beans that were traditionally roasted (by convection at 130°C for 30 minutes). The results show that the two different product types do not differ significantly in color, hardness, melting tendency and flow behaviour.
On the contrary, the sensory analysis, carried out with a panel of 27 people, made it possible to distinguish the different samples, mainly on the basis of the perceived aroma (higher cocoa aroma notes in the microwaved product compared to traditional cocoa). In general, there was a decidedly strong willingness to buy unconventional chocolate. Finally, microwave roasting ensures significantly lower energy consumption compared to convection treatment.
In conclusion, the results achieved so far are very promising in terms of developing innovative technologies for the chocolate industry. However, further analysis is necessary to assess the impact of microwave roasting on other quality aspects of the product, in particular on compositional aspects (polyphenol and other antioxidant contents).
References: A.W. Putranto et al., Food Science and Technology, 11, 2023, 71-83; J.J. Schouteten et al., Foods, 12, 2023, 1-11.
