Effect of acid‐ethanol treatment followed by ball milling on structural and physicochemical characteristics of cassava starch

Abstract

Structural and physicochemical characteristics of cassava starch treated with 0.36% HCl in anhydrous ethanol during 1 and 12 h at 30, 40, and 508C followed by ball milling for 1 h were analyzed. Average yield of acid-ethanol starches reached 98% independent of the treatment conditions. Solubility of acid-ethanol starches increased with reaction temperature and time, but it did not change after ball milling. Granule average size reduced with chemical treatment from 25.2 to 20.0 mm after 12 h at 508C. Ball milling decreased the granule average diameter of the native starch and those chemically treated at 308C/1 h or 408C/1 h, but it did not alter the starches treated for 12 h, independent of temperature. From scanning electron microscopy (SEM), starch granules presented round shape and after modification at 508C/12 h, before and after ball milling, showed a rough and exfoliated surface. Some granules were deformed, suggesting partial gelatinization that was more intense after milling. Starch crystallinity increased as temperature and time of chemical treatment were increased, while amylose content, intrinsic, and pasting viscosities decreased. Gelatinization temperatures increased for all chemical starches. The findings can be related to the preferential destruction of amorphous areas in the granules, which are composed of amylose and amylopectin. After ball milling, the starch crystallinity decreased, amylose content, intrinsic, and pasting viscosities kept unchanged and gelatinization temperatures and enthalpy reduced. Ball milling on native and chemical starches caused the increase of amorphous areas with consequent weakening and decreasing of crystalline areas by breaking of hydrogen bonds within the granules.

Combined effect of fermentation, sun-drying and genotype on breadmaking ability of sour cassava starch

“…The temperatures of gelatinization (T o , T p and T c ) and enthalpies (∆H) of 170 each sample were determined on the thermograms. The gelatinization temperature 171 range (∆T) was calculated as (T c -T o ) as described by Cavallini and Franco (2010 continuous stirring first at 960 rpm for 10 seconds and then at 160 rpm throughout 196 the rest of the experiment. Eight parameters were measured on the visco-197 amylogram: pasting temperature and pasting time (PT and Pt), peak viscosity 1 (PV1: 198 first viscosity peak after beginning of pasting), peak viscosity 2 (PV2: second 199 viscosity peak after beginning of pasting), time of peak viscosity 1 and 2 (tPV1 and 200 tPV2, respectively), lowest hot paste viscosity or holding strength (HS), final viscosity 201 (FV).…”

The effect of ball milling treatment on structure and porosity of maize starch granule

“…It has low amylopectin content and higher relative crystallinity. Native maize starch, sometimes, does not present adequate functional and physicochemical properties for use in much food and industry sectors (Cavallini & Franco, 2010). The physicochemical properties of starch and its application in food and industry are affected by its structure, such as relative crystallinity, the ratio of amylose to amylopectin, surface morphology of starch granule and the particle diameters of granules (Sandhu & Singh, 2007;Singh, Inouchi, & Nishinari, 2006).…”

Properties of maize starch modified by ball milling in ethanol medium and low field NMR determination of the water molecular mobility in their gels

“…The degradation of the glycosidic linkages of amylopectin probably occurs at the branch points, which release the long chains of amylopectin that were recorded as amylose (Cavallini and Franco, 2010). However, the dry ball-milled starch (ratio 1:0; w:v) shows less amylose content than the moisturized starch at the same milling time (Fig.…”

“…Amylose is less affected by physical treatment impact compared with amylopectin and severe damage only caused slight amylose depolymerization (Han et al, 2002). In fact, maize starch modified with acid in aqueous or aqueousealcoholic medium, provided fragile granules that could be broken into small particles by friction in a pestle or by ball milling (Cavallini and Franco, 2010). However, damaged starch showed lower and higher sorptive capacities than undamaged starch in the region of low and high water activity, respectively (Mok and Dick, 1991).…”

“…Ball milling of starches after being treated with acid and ethanol led to an increase of their solubility, to the reduction of their crystallinity, shear stress and apparent viscosity (Han et al, 2002), to the reduction of their gelatinization temperature and enthalpy. However, amylose content, intrinsic and pasting viscosity remained unchanged (Cavallini and Franco, 2010). Amylose is less affected by physical treatment impact compared with amylopectin and severe damage only caused slight amylose depolymerization (Han et al, 2002).…”