Physicochemical and morphological changes in corn grains and starch during the malting for Palomero and Puma varieties

Abstract

Background and objective Although corn is the most consumed and studied cereal in Mexico as food, its potential in fermented beverage production is less considered. The objective was to study the morphological and physiochemical changes during malting for Palomero and Puma corns, and to compare them with malted barley to determine the potentials of this cereal in the beer industry. Findings The SEM images of the malted starches showed a selective enzymatic attack and germination rate and reducing sugars behaved as S‐shape (logistic curve). The X‐ray diffraction patterns showed that the process did not modify the crystalline structure of these starches. The pasting profile showed changes in the peak viscosity and final viscosity, associated with amylose degradation, debranching of amylopectin, and the increase in reducing sugars. The IR analysis showed that during the malting time, the lipids had a drastic change. Conclusions Significant changes were found in the nutrimental composition after malting such as loss in fat and carbohydrates, while no significant differences were found in protein and ashes. The SEM images of the malting showed a selective enzymatic attack, and X‐ray diffraction patterns showed that process does not modify the crystalline structure of this starch. Changes in the pasting profile indicate that the malting decreases the peak and final viscosity. Significance and novelty The X‐ray results clearly showed that the enzymatic attack takes place on the amorphous component of the starch, while in the case of corn the crystalline A‐type orthorhombic structure does not suffer any change. These results indicate that corn malt can be suitable for brewing purposes.

Comparative analysis of malt quality and starch characteristics of three South Korean barley cultivars

“…The relative crystallinity was detected in the following order: KMB > HHB > HPB, with HPB exhibiting a significantly (P < 0.05) low level of 18.5% (Table 2 ). In line with previous studies (Hernández-Becerra et al, 2020 ), no change in A-type crystal structures was observed in this study; however, a peak of weak intensity was observed at 17° 2θ and 18° 2θ for HPM, and the relative crystallinity was reduced across all cultivars after malting (Table 2 ). This suggests that certain crystalline regions may experience a slight decrease due to the activity of starch hydrolase during malting.…”

“…A recent study using corn in malting observed fine holes in the starch particles in the regions of hydrolase attack and no change of A-type starch crystal structures as the enzymatic activity was selective during malting. The results indicated that an enzymatic attack had occurred in the amorphous region of the starch particles (Hernández-Becerra et al, 2020 ).

Fig.

…”

“…Nonetheless, the molecular weight distribution showed a considerable decrease in peak 1 (amylopectin), implying that the cause of the reduced molecular weight and starch crystallinity may be owing to amylopectin debranching rather than amylose content or chain length distribution during malting (Table 2 ). The attack of starch hydrolytic enzymes influenced the amorphous region (Hernández‐Becerra et al, 2020 ). The starch crystallinity was lower in HPB than in the other two cultivars.…”

Efecto de las modificaciones con ácido acético e hidróxido de calcio sobre las propiedades funcionales y reológicas del almidón de ñame (Dioscorea esculenta l.)

“…La nula afectación de la superficie del granulo, se debe a que la modificación no involucró ningún tipo de tratamiento enzimático. La base Ca (OH)2 y el ácido CH3COOH, no degradan la superficie del granulo, contrario a lo que sucede con las enzimas bacterianas [24], o en procesos fermentativos o fisiológicos [25], con enzimas propias del proceso de germinación de semillas. Se pueden observar algunas formas sobre las micropartículas, que no se podrían clasificar como alteraciones del granulo, sino más bien, algunas estructuras adheridas al granulo, que pueden ser proteínas, o polisacáridos no amiláceos, relacionados con la dificultad que presentó la harina para su purificación.…”

Malt Quality Characteristics of Selected Maize Varieties

“…Malts from wheat, sorghum and finger millet have been tested for their malting efficiency and as adjuncts in brewing [13]. Sorghum and maize are usually used adjuvants in Europe as alternatives for malt [14,15,16]. Malted maize and sorghum along with the barley malt are in use in the production of some brands of beer [17].…”