Características estruturais e físico-químicas de amidos de mandioquinha-salsa (Arracacia xanthorrhiza)

Abstract

O amido é um carboidrato encontrado em abundância na natureza, só competindo em quantidade com a celulose. Apresenta-se na forma de grânulos com formato e tamanho dependentes da sua fonte botânica. Devido as suas propriedades físico-químicas e funcionais exclusivas, este carboidrato tem grande importância nos mais diversos setores industriais. Na indústria de alimentos nacional e na internacional o amido é utilizado como ingrediente, podendo, entre outras funções, facilitar o processamento, fornecer textura, servir como espessante, fornecer sólidos em suspensão ou proteger os alimentos durante o processamento. Pode ser utilizado na sua forma natural ou, por intermédio de processamentos adicionais, dar origem a produtos como amidos modificados, xaropes de glicose, maltose ou frutose e maltodextrinas, entre outros (FRANCO et al., 2001).Os grânulos de amido são misturas heterogêneas de duas macromoléculas, amilose e amilopectina, que diferem no tamanho molecular e grau de ramificação (MIZUKAMI; TAKEDA; HIZUKURI, 1999). A amilose é uma molécula essencialmente linear formada por unidades de glicose ligadas em α-1,4, apresentando pequeno número de ramificações (BULÉON et al., 1998), enquanto a amilopectina é uma molécula altamente ramificada, também composta de unidades de glicose ligadas em α-1,4, mas com 5 a 6% de ligações α-1,6 nos pontos de ramificação (FRENCH, 1984;LINEBACK, 1984).A compreensão da estrutura dos grânulos de amido é importante no entendimento de suas propriedades físico-químicas, as quais determinam o comportamento do amido natural ou AbstractStarch has very important physicochemical properties that depend on its botanical source and structural characteristics. Peruvian carrot starch displays special characteristics, which make it appropriate for industrial application in many processed foods. In this work, starch from two Peruvian carrot varieties, Amarela de Carandaí (AC) and Amarela de Senador Amaral (ASA), were isolated and their physicochemical and structural properties were determined. Starch from the ASA variety exhibited granules with a greater average diameter than those from the AC variety and more than double the number of granules with size ≥20 μm, when compared to the other variety. Starches from both varieties, observed in a Scanning Electron Microscope, showed smooth granule surface with circular and polyhedral shapes for large and small granules, respectively. Molecular size distribution, intrinsic viscosity and degree of cristallinity of starches from both varieties were similar; however, amylose content was higher for the starch from the AC variety. Higher values of viscosity, swelling power and gelatinization temperatures were observed for the starch from the ASA variety, which could be related to the lower amylose content and the higher proportion of large granules exhibited by this starch. Keywords: starch; Peruvian carrot; structural characteristics; physicochemical properties. ResumoO amido apresenta propriedades físico-químicas importantes que são dependentes de sua fonte bo...

Effect of enzymatic hydrolysis on some physicochemical properties of root and tuber granular starches

“…The gelatinization temperatures and enthalpy changes of native starches are shown in Table 5, which displays values close to those found in the literature (HOOVER, 2001;DEMIATE;FRANCO, 2008;GANGA;CORKE, 1999). After statistical analysis, it was observed that the gelatinization temperatures (T o , T p , T c ) and ΔH for all starches remained unchanged after hydrolysis, except for the peak temperature of the hydrolyzed cassava starch that was lightly lower when compared with the native cassava starch.…”

“…The hydrolyzed potato starch granules showed only a slight signal of exocorrosion an A-type X-ray diffraction pattern for cassava and sweet potato starches (Figure 2 a, b) while Peruvian carrot and potato starches showed a B-type pattern (Figure 2 c, d). In a previous study, Rocha, Demiate and Franco (2008) reported a B-type pattern for Peruvian carrot starch which was also reported by Santacruz et al (2003). Starches with A-type polymorphism are more susceptible to amylases action than starches with B-type polymorphism (JANE, 2006;HOOVER;ZHOU, 2003;GÉRARD et al, 2001).…”

“…Hoover (2001) found values varying from 18.6 to 25.6% for the cassava starch depending on the plant variety. Also, according to Moorthy (2001), the sweet potato starch was found to have an amylose content of 20-25% depending on the variety, and Rocha, Demiate and Franco (2008) observed values of 21.7 and 17.8% for starches from two varieties of Peruvian carrot. Cottrell et al (Figure 4h↓).…”

Peach Palm (Bactris gasipaes kunth) Characterization and the Potential of by-Products Flour Processing

“…The sheaths and the stem portion can be processed into flours that have a potential market as a new food ingredient rich in dietary fibers (DF). However, during the processing of the flours browning can occur darkening the product (Rocha et al, 2008). The dried samples were coated with gold in the Sputter Coater (Baltec-Balzers SCD 050) and the images were obtained in scanning electron microscopy .…”

STARCH EXTRACTION FROM THE PEACH PALM (Bactris gasepaes Kunth.) FRUIT: A MODEL APPROACH FOR YIELD INCREASE

“…By put forward better results for optimization than other statistical methods, the RSM was utilized in this work. The independent variables investigated are the concentrations of sodium hydroxide (NaOH) and sodium bisulfite (NaHSO3), in addition to decantation time, according to previous analysis and contributions of literature (ROCHA et al, 2008;DEVEREUX et al, 2011;MADRIGAL-ALDANA et al, 2011).…”