Optimization of Crude Inulin Extraction from Garlic (Allium sativum L.) Agro-industrial Waste using the Response Surface Methodology.

Abstract Inulin is a polysaccharide with several applications within the chemical, pharmaceutical, and food industry. It is considered a dietary fibre that provides multiple health benefits. In this work, the yield of raw inulin obtained from garlic agro-industrial useless waste was maximized, by applying the response surface methodology in a central composite design (CCD), in which different distilled-water (DW)-to-garlic-agro-industrial-waste (GAIW) ratios (3 and 5 mL/g) and different temperatures (60 and 80 °C) were evaluated. Optimal condition was obtained with a DW/GAIW ratio of 4.3 mL/g and a temperature of 80.2 °C. Under this condition, the quadratic model showed a maximum yield of crude inulin of 8.17 ± 0.89 g/100 g. Further, the CCD model obtained was validated with three additional experiments at the same optimal condition. The FTIR spectra of inulin obtained from garlic agro-industrial residues and chicory inulin showed similarities and differences, presumably related to the different degrees of polymerization of the fructans present.