Thermal properties of tannin extracted from Anacardium occidentale L. using TGA and FT-IR spectroscopy

Abstract

The chemical nature of the polyphenols of cashew kernel testa has been determined. Testa contains tannins, which present large molecular complexity and has an ancient use as tanning agents. The use of tannins extracted from cashew testa, considered in many places as a waste, grants an extra value to the cashew. In this work we have analysed through high performance liquid chromatography, infrared spectroscopy (FT-IR) and thermo gravimetric analysis the average molecular weight, main functional groups and thermal properties of tannins extracted from Anacardium occidentale L. The results of these analyses are compared with the commercial grade tannic acid. The FT-IR spectra showed bands characteristic of C = C, C-C and OH bonds. This important bioactive compound present in the cashew nut kernel testa was suggested as an interesting economical source of antioxidants for use in the food and nutraceutical industry.

Synthesis of a novel highly efficient flame-retardant coating for cotton fabrics with low combustion toxicity and antibacterial properties

“…This confirms the presence of carbon hydrogen chains in the char structure. The peak at 1630 cm -1 is for aromatic structure, the peak at 1400 cm -1 is for C-N and C=N groups, the peak at 1160 cm -1 is for P-O, the peak at 1050 cm -1 is for P-O-C, the peak at 984cm -1 is for polyphosphate and/or pyrophosphate, the peak at 881 cm -1 is for alkene, the peak at 492cm -1 is for O-P-O group (Abdelkhalik et al 2020(Abdelkhalik et al , 2019Wahyono et al 2019;Makhlouf et al 2017a,b;Viswanath et al 2015;Chen and Wang, 2007).…”

Anacardium Plants: Chemical,Nutritional Composition and Biotechnological Applications

“…A comparative analysis of results was made using tannic acid. The bands characteristic of CvC, CZC and OH bonds were exhibited by FT-IR spectra [63]. Likewise, the average molecular weight, main functional groups and thermal properties of tannins isolated from A. occidentale were investigated using HPLC, FT-IR and thermogravimetric analysis.…”

“…Likewise, the average molecular weight, main functional groups and thermal properties of tannins isolated from A. occidentale were investigated using HPLC, FT-IR and thermogravimetric analysis. Bands characteristic of C=C, C-C and OH bonds were identified through FT-IR spectra analysis [63]. Tannin content was also investigated in the testa obtained from high-yielding varieties of cashew and from samples of commercial cashew processors in India and compared with almond testa.…”

Antioxidant and Anti‐Inflammatory Properties of Anacardium occidentale Leaf Extract

“…When the cells were LPS-stimulated, the lowest doses of 0.5 μ g/mL and 5 μ g/mL cotreatment inhibited the decrease in cell viability mediated by LPS. It is known that phytochemical composition of the plant Anacardium occidentale presents phenolic compounds, such as quercetin, anthocyanins, and tannins [ 31 – 33 ]. These phytochemical compounds are related to several biological activities, including antioxidants, apoptotic, antiapoptotic, and anti-inflammatory activities [ 34 ].…”