Structural modification of waxy, regular, and high‐amylose maize and hulless barley starches on partial acid hydrolysis and their impact on physicochemical properties and chemical modification

Abstract

Waxy (WX), regular (RA), and high-amylose (HA) maize and hulless barley (HB) starches were subjected to partial acid hydrolysis with 1.0 and 2.2 N HCl for 30-240 min. In both starches, the extent of hydrolysis with 1.0 N HCl followed the order: HA>WX>RA, whereas with 2.2 N HCl, the order was: HA>WX>RA (maize) and WX>HA>RA (HB), respectively. The relative crystallinity increased (HA>WX>RA) and the X-ray pattern remained unchanged, whereas the swelling factor decreased (WX>RA>HA in maize and WX>HA>RA in HB) at both acid concentrations. Starches hydrolyzed with 1.0 N HCl exhibited increased gelatinization temperatures (WX>RA>HA in maize, WX>HA $ RA in HB), a narrower gelatinization temperature range (WX>RA>HA in maize, WX>RA $ HA in HB) and a decreased gelatinization enthalpy (WX>HA>RA in maize and HB). Acid hydrolysis increased the accessibility of the phosphorylating reagent into the amorphous regions. The extent of phosphorylation was more pronounced (maize>HB) in starches hydrolyzed with 1.0 N HCl for 60-90 min. The bound phosphorus content (BPC) followed the order: HA>WX>RA in maize and HB starches hydrolyzed with 1.0 N HCl for 240 min. In both starches, the extent of cationization was not influenced either by acid concentration or hydrolysis time. In general, acid hydrolysis significantly affected the reactivity of starch towards phosphorylation, where the optimum hydrolysis condition differed with starch source. The results would benefit the starch industry, since the amount of the phosphorylating reagent required for increasing thermal stability and/or freeze-thaw stability could be decreased substantially, if starches are subjected to partial acid hydrolysis prior to derivatization.

Ultrasound-assisted acid-thinning of corn starch: Morphological, physicochemical, and rheological properties

“…The SP of acid‐treated samples at 10 and 20°C for both concentrations were higher ( p < 0.05) than control but their values remained close ( p > 0.05) to control in case of samples sonicated at 40°C (Table ). This is in accordance with the results reported by others , which reported acid treatment diminishes the SP.…”

“…The slight changes in S of samples in present study may be explained based on alterations induced on molecular properties of leached AM and AP. As previously explained, both AM and AP undergo chain scission or debranching to yield an increasing population of linear and partially degraded chains which are capable to prone aggregate in the form of gelling or retrogradation , thus limiting the water absorption resulting in a slight solubility.…”

Effect of Acid-Alcohol Treatment on Physicochemical Properties of Ball-Milled Potato Starches

“…Therefore, samples PS1.5 and PS3 with or without acid‐alcohol treatment exhibited higher swelling power and better solubility at low temperature (30 °C). A decease in swelling power after long hydrolysis time in samples PS1.5 and PS3 may be attributed to the disconnection between amorphous and crystalline regions of amylopectin …”

“…Many researchers also found that the botanical origin and crystalline type of starch could influence the hydrolysis kinetics, which meant that the different inner structure of starch granules had a different acid hydrolysis process. However, up to now almost all studies on the physicochemical properties of acid hydrolyzed starch are based on the native starch treated by acid . There is still little insight on the acid hydrolysis of modified starch with different crystalline structure.…”

Thermoplastic Waxy Starch Films Processed by Extrusion and Pressing: Effect of Glycerol and Water Concentration

“…Starch consists of two major components, the linear amylose and the highly branched amylopectin 2,3 . There are three types of starch wherein the amylose concentration ranges: native starch (15-30 wt% amylose); waxy starch (0-5 wt% amylose); and high amylose starch (35-70 wt% amylose) 2,3 . Native starch is not processible and this drawback can be resolved by plastification process [4][5][6] .…”