Hot air drying of yacon (Smallanthus sonchifolius) and its effect on sugar concentrations

Abstract

This work aimed to experimentally study the drying behaviour of yacon tubers with and without steam blanching. Drying was carried out for 5 h and 30 min in a forced air dryer at 50°C, 60°C and 70°C. The results indicated that the shortest drying time was obtained at 70°C for blanched samples, and that the equilibrium water activity values were significantly lower for the blanched samples at all temperatures. The yacon dried without prior blanching showed lowest concentrations of reducing sugars when dried at 70°C, significantly lower than those dried at 50°C and 60°C. This indicates hydrolysis of the fructooligosaccharides at 70°C, a fact verified by the significant increase in reducing sugars content from 36.65 ± 0.54-44.10 ± 0.96% and reduction in the non-reducing sugars from 31.62 ± 0.55-26.18 ± 0.29%.

Studies of chemical and enzymatic characteristics of Yacon (Smallanthus sonchifolius) and its flours

“…In the in natura yacon pulp, moisture content was close to the values found in the literature, which are between 81.7% and 88.7% (LAGO, 2010;SCHER;NOREÑA, 2009;MARANGONI, 2007).…”

“…The PER enzymatic activity was also higher in the peel when compared to that of the yacon pulp. Besides, the enzymatic activity of PER in the in natura yacon pulp was higher than that found by Scher, Rios and Noreña (2009) in the same product, 22.0 U.g -1 .min -1 .…”

“…The peel and the pulp were immersed in a sodium hypochlorite 20 mg.L -1 and sodium bisulphite 0.1% solution for 15 minutes. Next, the peel and pulp were submitted to forced ventilation oven drying at 55 °C (PADILHA et al, 2009;SCHER;NOREÑA, 2009) for 72 hours and 96 hours, respectively; the time was determined by pre-testing until they reached the desired moisture content. After drying, they were milled using a multiprocessor until ootsturning into the flour.…”

Use of Different Kinds of Solutes Alternative to Sucrose in Osmotic Dehydration of Yacon

“…These values were in accordance with Manrique et al (2005) who reported that about 85 to 90% of the fresh weight of yacon consisted of water and with Scher et al (2009) who found moisture of 88.69 ± 0.10%, soluble solids of 9.9 ± 0.01 °Brix and pH 6.09 ± 0.02. Figure 1 presents the mass loss of the samples over time for the four solutes used in this work.…”

Physicochemical characterization of saccharides powder obtained from yacon roots (Smallanthus sonchifolius) by membrane technology

“…The saccharides content (FOS, glucose and fructose) in final NF-retentate was evaluated by the high performance liquid chromatography (HPLC) as described by Zuleta and Sambucetti (2001) and Scher et al (2009), using a Perkin Elmer series 200 chromatograph equipped with a refractive index detector (HPLC-RI) (PerkinElmer Life and Analytical Sciences, Shelton, CT, USA) and ultrapure water as the mobile phase at 0.6 mL.min -1 , temperature of 80°C and a Phenomenex Rezex RHM monosaccharide column, 330 mm·7.8 mm, with a total run time of 14 min. Reference sugars (glucose, fructose and inulin) were purchased from Sigma-Aldrich.…”