INSTRUMENTAL COLOR PARAMETERS AND STRUCTURAL PROPERTIES OF CARÁ (Discorea alata L.) FLOUR

Cará (Discorea alata L.) is a herbaceous plant with underground rhizomes belonging to the family Dioscoriaceae and genus Dioscorea, which can be used in food formulations in order to increase its caloric and nutritional value. Thus, the objective of the present study was to determine the instrumental parameters of color, relative crystallinity and infrared (IR) spectroscopy of its flour (CF) in order to increase scientific knowledge about this rhizome. The instrumental color parameters (L*, a*, b*) were determined on a portable spectrophotometer (Konica Minolta, BC-10, USA). Infrared spectrum was determined by spectrometer (PerkinElmer, Spectrum 400, USA). The X-ray diffraction pattern was determined on a bench diffractometer (Rigaku, MiniFlex 300, Tokyo, Japan). CF presented 19.08% ± 2.16 of relative crystallinity showing peaks at 2θ, 5.54º, 15.13º, 17.21º, 22.32º and 24.14º, characteristic of type B crystallinity pattern, suggesting that the starch present in CF has a more organized structural packaging, and consequently, has higher resistance to enzymatic digestion compared to flours containing type A crystallinity starches, and can be used in the elaboration of functional foods that contribute to better nutrition. CF presented L *=82.28±0.24, a*=1.86±0.08, b*=9.16±0.16, C*=9.72±0.29 and ºH=85.67±0.26, thus, it may be recommended for use in products that require a uniform color, for example ice cream and candy. Regarding the infrared spectrum, the peak of 1651.26cm-1 was related to the vibrational elongation of the amino group (N-H) of proteins. The bands found between 1189 and 947cm-1 were associated with carbonyl group (C-O) of amylopectin and amylose molecules. The large absorption band in the region between 3051-3789cm-1 was attributed to the stretching and angular deformation of hydroxyl group (O-H) bonds in the water molecule. From the analyzed parameters, it was possible to acknowledge some of the physical and structural characteristics of CF, expanding its knowledge and enabling future applications.