Effect of pretreatments on quality of Jerusalem artichoke (Helianthus Tuberosus L.) tuber powder and inulin extraction

Abstract

© 2015 American Society of Agricultural and Biological Engineers. In this study, Jerusalem artichoke tuber (JAT) samples were pretreated in four different ways including nonpeeling/blanching, non-peeling/non-blanching, peeling/blanching, and peeling/non-blanching prior to hot air drying and milling into fine powder. The physical characteristics of Jerusalem artichoke tuber powder (JATP) specimens were determined in terms of color, moisture content, pH, microstructure, particle size, and solubility. Furthermore, JATP specimens were processed into inulin powder by applying extraction, evaporation, and spray drying procedures. Both JATP and inulin powder samples from four pretreatments were analyzed for their sugars, fructo-oligosaccharides (FOS), and inulintype fructan contents. The aims of this research were to (1) determine the appropriate pretreatment condition for JAT in order to obtain superior-quality JATP and inulin powder products, (2) investigate the sugars, FOS, and inulin-type fructans in JATP and inulin powder, and (3) evaluate the yield of inulin powder production from JATP. The results indicated that non-peeling/blanching was the pretreatment that should be applied for JATP and inulin powder production because it provided JATP with the lowest sugars (10.00 ±1.59 g per 100 g dry mass) and high inulin-type fructans (39.09 ±0.87 g per 100 g dry mass) and provided spray-dried inulin powder with the lowest sugars (23.62 ±0.98 g per 100 g dry mass) and the maximum inulin-type fructans (56.29 ±0.58 g per 100 g dry mass). In addition, the benefit of blanching is to help preventing the browning reaction during inulin powder production. The extraction process could separate some impurities and increase the sugars, FOS, and inulin-type fructan contents in powder products. Additionally, the yields of inulin powder production ranged from 45.56% to 59.85% of the JATP dry weight.