Dados do Trabalho

Título

SCALE UP PROCESS FOR COFFEE FERMENTATION AND ITS INFLUENCE ON COLOR AND TEXTURE PARAMETERS OF GREEN BEANS

Introdução

Coffee fermentation is employed to add value to the final beverage, which has yet to be validated from an industrialization perspective and can be a key factor to determine effects for storage conditions and sales transactions. This study aimed to evaluate the color and texture of green beans from natural arabica coffee (Catiguá MG2 cultivar) fermented in different scale sizes.

Material e Métodos

Fruits cultivated at 1048 m in Cerrado Mineiro region were fermented for 60 h in solid-state at ambient temperature on self-induced anaerobiosis with epiphytic microbiota. Fermentations were performed in high-density-polyethylene bioreactors with capacities of 200 (B1) and 1000 L (B2), and in 14000 L (B3) steel bioreactor. After fermentation, sun-drying and husking, the beans were sorted and analyzed; a non-fermented control sample (C) was also evaluated. Color parameters were measured in quintuplicate with CIELab colorimeter (D65, 2°); color difference (∆E) and yellowness index (YI) were calculated with chromatic values. Texture profile analysis (TPA-AIBCAKE2 macro) was based on rupture strength and hardness parameters (given in g force) and were conducted in triplicate with an aluminum probe (25 mm), return distance of 20 mm, return speed of 30 mm/s, contact force of 30 g, and strain of 70%. Statistical differences were verified using ANOVA and Tukey’s test (p<0.05).

Resultados e Discussão

Color analysis showed that fermented samples were lighter (L*: C=29.95a, B1=36.13b, B2=33.57c, B3=35.79b). B3 had the highest values for red-green (a*: C=0.87a, B1=1.12a, B2=1.14a, B3=1.66b) and yellow-blue (b*: C=12.40a, B1=15.70b, B2=14.54c, B3=18.37d) axis and the most significant ∆E (B1=4.70a, B2=3.05b, B3=6.57c). B1 and B2 presented the same yellowness and B3 showed the highest YI (C=59.49a, B1=64.82b, B2=64.03b, B3=72.94c). Control sample had the lowest rupture strength (C=36049a, B1=42392bc, B2=47657b, B3=41503c) and hardness (C=37092a, B1=45534b, B2=47535b, B3=43267c), indicating that fermentation in all bioreactors could have increased the support charge capability for storage.

Conclusão

In this regard, even though the scale up did not affect texture, the building material of B3 (compared with B1 and B2) facilitated heat transfer in coffee bed and resulted in yellower beans due to higher fermentation rate, which can have a directly negative impact in sensory quality when combined with uncontrolled external temperature.