Extraction and chemical characterization of starch from S. lycocarpum fruits.

In this study the pulp from Solanum lycocarpum fruits was used as raw material for extraction of starch, resulting in a yield of 51%. The starch granules were heterogeneous in size, presenting a conical appearance, very similar to a high-amylose cassava starch. The elemental analysis (CHNS) revealed 64.33% carbon, 7.16% hydrogen and 0.80% nitrogen. FT-IR spectroscopy showed characteristic peaks of polysaccharides and NMR analysis confirmed the presence of the α-anomer of d-glucose. The S. lycocarpum starch was characterized by high value of intrinsic viscosity (3515 mPa s) and estimated molecular weight around 645.69 kDa. Furthermore, this starch was classified as a B-type and high amylose content starch, presenting 34.66% of amylose and 38% crystallinity. Endothermic transition temperatures (To=61.25 °C, Tp=64.5 °C, Tc=67.5 °C), gelatinization temperature (ΔT=6.3 °C) ranges and enthalpy changes (ΔH=13.21 J g(-1)) were accessed by DCS analysis. These results make the S. lycocarpum fruit a very promising source of starch for biotechnological applications.