The Comparison of Inulin Extraction Methods from Jerusalem Artichoke (Helianthus tuberosus)

Abstract

The comparison of inulin extraction methods from Jerusalem artichoke was investigated. The extraction methods consisted of 1) distilled water at 80ºC, 2) 80% ethanol (v/v) at 80ºC, 3) microwave extraction (406W) for 60 minutes, and 4) ultrasonic extraction at 80ºC for 60 minutes. The study of the chemical composition of Jerusalem artichoke powder revealed the moisture content of 14.01±0.04% with crude protein, crude fat, crude fiber, ash and carbohydrates content of 2.93±0.09, 1.27±0.01, 3.98±0.04, 1.03±0.05 and 76.78±0.04, respectively. Total sugar, reducing sugar and inulin content of Jerusalem artichoke extract solution were analyzed. It was found that the extraction method using ethanol solution showed the highest of total sugar (136.867+10.22 mg/ml) and the inulin content (66.526±6.10%) compared to other methods. The microwave extraction resulted in the highest reducing sugar content (6.689±1.86 mg/ml) (p≤0.05). The total soluble solids (TSS) of inulin extracted using ethanol, distilled water and microwave extraction showed higher than ultrasonic extraction methods (p≤0.05). However, pH of the inulin extracted solution was non significantly different (p>0.05). Color analysis of L* a* and b* was also investigated. Inulin extracted solution from distilled water displayed the highest brightness (L*) (29.37±0.13) (p≤0.05). The redness value (a*) of inulin extracted solution using the four extraction methods was not significantly different (p>0.05). Inulin extracted solution using distilled water showed the highest yellowness value (b*) (4.79±0.02) (p≤0.05), followed by ethanol, microwave and ultrasonic extraction methods (4.55±0.16, 3.84±0.06 and 3.74±0.07, respectively). Therefore, the extraction method using 80% ethanol (v/v) at 80ºC provided the highest inulin content and did not eliminate physical and chemical properties of Jerusalem artichoke.