The objective was to compare the action of different hydrolases for producing porous corn starches. Amyloglucosidase (AMG), α-amylase (AM), cyclodextrin-glycosyltransferase (CGTase) and branching enzyme (BE) were tested using a range of concentrations. Microstructure, adsorptive capacity, pasting and thermal properties were assessed on the porous starches. SEM micrographs showed porous structures with diverse pore size distribution and pore area depending on the enzyme type and its level; AMG promoted the largest holes. Adsorptive capacity was significantly affected by enzymatic modification being greater influenced by AMG activity. Unexpectedly, amylose content increased in the starch treated with AMG and BE, and the opposite trend was observed in AM and CGTase treated samples, suggesting different mode of action. A heatmap illustrated the diverse pasting properties of the different porous starches, which also showed significant different thermal properties, with lower To and Tp. Porous starch properties could be modulated by using different enzymes and concentrations.

Porous starches might offer an attractive alternative as bio-adsorbents of a variety of compounds. However, morphology and physicochemical properties of starches must be understood before exploring their applications. Objective was to study the action of different amylolytic enzymes for producing porous starches. Wheat, rice, potato and cassava starches were treated with Amyloglucosidase (AMG), α-amylase (AM) and cyclodextrin-glycosyltransferase (CGTase). Morphological characteristics, chemical composition, adsorptive capacity and pasting/thermal properties were assessed. Scanning Electron Microscopy (SEM) showed porous structures with diverse pore size distribution, which was dependent on the enzyme type and starch source, but no differences were observed in the total granule surface occupied by pores. The adsorptive capacity analysis revealed that modified starches had high water absorptive capacity and showed different oil adsorptive capacity depending on the enzyme type. Amylose content analysis revealed different hydrolysis pattern of the amylases, suggesting that AMG mainly affected crystalline region meanwhile AM and CGTase attacked amorphous area. A heatmap illustrated the diverse pasting properties of the different porous starches, which also showed significant different thermal properties, with different behavior between cereal and tuber starches. Therefore, it is possible to modulate the properties of starches through the use of different enzymes.

No abstract

Colocasia esculenta, belonging to the Araceae family, represents an attractive alternative as gluten-free (GF) main ingredient owing its healthy pattern. The aim was to explore the GF breadmaking potential of Colocasia spp. cormels flour, thermally treated or blended with hydrocolloids (HPMC, xanthan gum, guar gum), enzymes (glucose oxidase or proteases) or potato starch. A total of eight formulations were used to obtain GF bread-like products. Resulting breads were characterized based on their technological quality, but also on their functional quality by in vitro starch digestion. Colocasia spp. cormels flour-based breads displayed similar quality parameters observed in previous reported GF formulations. The addition of an endoprotease allowed developing breads with higher specific volume, but the alcalase type protease increased crumb softness. In general, resulting GF breads contained higher SDS and RS fraction than RDS fractions. A better starch digestibility pattern than those previously reported in GF breads was also observed, which confirm the potential of Colocasia spp. cormels flour as novel nutritive source of GF flours.

No abstract