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Functional properties of starch obtained from Peach palm (Bactris gasipaes var. gasipaes) by alkaline way

Abstract:

Fruits of peach palm (Bactris gasipaes var. gasipaes) or “chontaduro”, a species native to the Amazon, have potential industrial applications because of their high starch content. Currently, starch is a relevant raw material for several industries because it is inexpensive, biodegradable, versatile and renewable. For this reason, chontaduro fruit meal (BGM) was used for extracting starch (BGS) via the alkaline method. BGS was characterized by analyzing its physicochemical properties, such as moisture, raw fat, ash content, total fiber, total protein, total carbohydrates and amylose; its functional properties, such as the water-absorption index (WAI), swelling power (SP) and water solubility index (WSI); its morphological and structural properties by scanning electron microscopy (SEM); pasting properties via a Rapid Visco Analyzer RVA for determining the peak viscosity (PV), final viscosity (FV), pasting temperature (PT), breakdown (BD) and setback (SB); thermal properties via differential scanning calorimetry (DSC); and molecular structure via Fourier transform infrared spectrometry (FTIR). The main components in BGM were carbohydrates (63.8%), fat (10.7%), protein (4.7%), and crude fiber (10.1%). When alkaline extraction was applied, these values changed, and BGS values were as follows: carbohydrates (85.6%), fat (0.4%), protein (1.1%), crude fiber (0.7%), and amylose (13.5%), with a starch extraction yield of 12%. The functional properties WAI, SP and WSI were dependent on temperature and ranged from 2.8–6.2%, 2.9–6.4% and 3.8–7.0%, respectively. The BGS showed no changes in morphological properties, as shown by the SEM micrographs. The pasting properties were PT=89.4 °C, PV=2407 (cP), BD=707 (cP), and SB=1191 (cP). BGS showed a moderate gelatinization temperature of 65 °C and a ΔH of 2.479 Jg<sup>-1</sup>. Finally, the FTIR spectrum revealed the typical form of an unmodified or native starch. On the basis of these results, chontaduro fruits may be considered a natural, nonconventional source of starch with potential applications in the food and pharmaceutical industries.