Effect of the alkaline and acid treatments on the physicochemical properties of corn starch

Abstract

Corn starches were isolated using three different methods: water steeping, alkaline steeping, and acid steeping. The effects on their structural, micro structural, thermal, and chemical properties were evaluated, with especial emphasis in the alkaline process that is close related to the nixtamalization process. The isolation method influences the amylose content, crystallinity, and enthalpy of the starch granules. Scanning electron microscopy showed that the isolation method produced changes on the surface of the granules, and in some cases there were holes on the surface. Method 2 (the alkaline method) produces the starch granules with low protein and fat content and there was an increase in the enthalpy for this method, that can be explained in terms of thermodynamics by the increase of particles into the starch granules, which was confirmed by an increase in the ash content. A negative correlation between these variables was found (r ¼ 70.99), while a positive correlation between enthalpy and amylose content was also found (r ¼ 1).Keywords: corn starch; isolation method; functional properties of starch; amylose; amylopectin Almidones de maı´z fueron aislados por tres diferentes me´todos: usando reposo en agua, reposo alcalino y reposo a´cido. Se evaluaron los efectos de estos me´todos sobre las propiedades estructurales, microestructurales, te´rmicas y quı´micas en los gra´nulos de almido´n. Los resultados mostraron que los me´todos de obtencio´n de almido´n tienen fuerte influencia en el contenido de amilosa en los almidones aislados, ası´como en su estructura cristalina obtenida mediante difraccio´n de rayos X, ası´como cambios en la superficie de los gra´nulos observados por microscopia electro´nica de barrido, se tiene especial e´nfasis en el proceso alcalino, por que es cercano al proceso de nixtamalizacion. El me´todo alcalino produjo gra´nulos de almido´n con bajo contenido de proteı´na y grasa. En el caso del tratamiento alcalino, en te´rminos termodina´micos, el incremento en la entalpia tambie´n puede ser explicado por el incremento de las partı´culas dentro de los gra´nulos de almido´n, resultado que es confirmado por el incremento del contenido de cenizas. Finalmente, se encontro´una correlacio´n (r ¼ 70,99) tomando en cuenta los valores de cristalinidad y entalpia, y una correlacio´n positiva (r ¼ 1) entre entalpia y contenido de amilosa.Palabras clave: almido´n de maı´z; me´todo de aislamiento; propiedades funcionales de almido´n; amilosa; amilopectina

Effects of Treatment Temperature on Properties of Starch-based Adhesives

“…The surfaces were corroded when starch was treated with acid and alkali. Rough surfaces indicated that both the amorphous and crystalline regions contributed to rough surfaces because both the amorphous and crystalline parts were hydrolyzed by the acid and alkali (Abdorreza et al 2012;Palacios-Fonseca et al 2013). PVA filled the spaces in the starch particles to a certain extent and covered the surfaces of the starch particles.…”

“…Chemical reagents such as acid (Zuo et al 2013;Shi et al 2009), alkali (Palacios-Fonseca et al 2013;Uthumporn et al 2012) and enzymatic (Hu 2007) treatments are often used in modification of starch. Acid treatment has been applied for the hydrolysis of starch granules and to produce soluble starch for many years.…”

Effects of heat‐moisture and alkali treatment on the enzymatic hydrolysis of porous sago ( Metroxylon sagu ) starch

“…Furthermore, it was suggested that the alkali treatment dissociated some of the double helices of starch granule and enabled it to be more vulnerable for enzymatic attack (Spier et al, ; Wang & Copeland, ). It was also reported that the starch isolated by alkaline steeping resulted in lower protein and lipid contents of starch (Palacios‐Fonseca et al, ).…”

Evaluation of Rheological Properties of Four Italian Rice Samples and Starch Thereof by RVA and FTIR Spectroscopy Supported by Double Two‐Dimensional Correlation Analysis: Evidence of Lipid–Carbohydrate Interactions

“…Matheson and Welsh (1988) suggested steeping grains in 0.2M aqueous ammonia solution for 48 h, macerating the solid pellet in 0.2M acetic acid, and extracting starch with 0.1M sodium chloride and toluene. Palacios-Fonseca et al (2013) used 0.1% (w/v) NaOH for 18 h, as suggested by Wang and Wang (2001), with slight modifications. Palacios-Fonseca et al (2013) used 0.1% (w/v) NaOH for 18 h, as suggested by Wang and Wang (2001), with slight modifications.…”