Comparison of porous starches obtained from different enzyme types and levels

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.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R) and the European Regional Development Fund (FEDER). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Enzymatic modification of starches to improve their technological and functional properties

En la última década, los polímeros porosos han atraído la atención de las industrias alimentarias y no alimentarias principalmente por su gran capacidad absorbente, la cual está determinada por el número y tamaño de poros. En este tipo de materiales se han integrado biopolímeros como los almidones tras ser sometidos a tratamientos físicos, químicos o enzimáticos. Estos últimos, son los que se consideran más prometedores al originar biopolímeros etiqueta limpia. Sin embargo, los estudios realizados no permiten un control de la porosidad de los almidones. El objetivo de esta tesis doctoral fue el estudio integral de la producción de almidones porosos mediante tratamientos enzimáticos que permitieran modular las propiedades estructurales y tecnológicas de los almidones. Para conseguir dicho objetivo se utilizaron almidones nativos de distintos orígenes (maíz, trigo, arroz, patata, tapioca) y distintas enzimas hidrolíticas (amiloglucosidasa, alfa amilasa, ciclodextrin glicosil transferasa, enzima ramificante) para la obtención de almidones porosos, los cuales se caracterizaron atendiendo a sus propiedades estructurales, tecnológicas y digestibilidad in vitro. Asimismo, se determinó su viabilidad como vehículos de probióticos. El análisis de superficie de los gránulos de almidón realizado mediante microscopía electrónica de barrido (SEM) indicó que la porosidad de los almidones se puede modular utilizando diversas estrategias como el empleo de enzimas con diferente actividad hidrolítica, variando la concentración de estas enzimas o utilizando almidones de distinto origen botánico. La amiloglucosidasa fue la hidrolasa que originó poros de mayor tamaño, los cuales fueron más profundos en los almidones de cereales. Además, el control de la porosidad permitió modificar la funcionalidad de los almidones, afectándose significativamente su capacidad de retener agua y aceite, su capacidad de formación de pasta, propiedades térmicas, e incluso su digestibilidad in vitro. Los almidones de maíz y arroz porosos obtenidos con alfa amilasas se aplicaron como vehículos de probióticos, observándose un incremento de la estabilidad térmica de Lactobacillus plantarum, sobre todo tras ser recubiertos con almidón gelatinizado. Además, el estudio realizado con los almidones porosos tras su gelatinización abre la posibilidad de obtener hidrogeles con propiedades estructurales y funcionales diversas.In the last decade, porous polymers have attracted the attention of the food and non-food industries owing their great absorption capacity, which is dependent on the number and sizes of the pores. In this type of materials have been incorporated diverse polymers like starches after being subjected to physical,\ud chemical or enzymatical treatments. The latter are considered the most promising due to the resulting materials are clean label polymers. However, up to now, the reported studies do not allow controlling the starch porosity. The objective of this doctoral thesis was the integral study of the production of porous starches by enzymatic treatment in order to modulate their structural and technological properties. With that purpose, native starches from different origin (corn, wheat, rice, potato and cassava) and diverse amylases (amyloglucosidase, alpha amylase, cyclodextrin-glycosyltransferase, branching enzyme) were used for producing porous starches, which were then characterized according to their structural and technological properties, as well as their in vitro digestibility. In addition, their viability as probiotic carriers was evaluated. The surface analysis of the starch granules, carried out by scanning electronic microscopy (SEM) indicated that the porosity of the starches could be modulated by either using enzymes with different hydrolytic activity, changing of enzymatic levels, or employing starches from diverse botanical origin. The amyloglucosidase led to porous starches with bigger pore sizes, and those were deeper in the case of cereal starches. Moreover, the control of starch porosity allowed changing the functionality of the starches, significantly affecting the water and oil holding capacities, the pasting and thermal properties and even their behavior during in vitro digestibility. Porous starches obtained from corn or rice after treated with alpha amylase were tested as probiotic carriers, yielding an increase of the thermal stability of Lactobacillus plantarum, especially after being coated with gelatinized starch. Additionally, the study carried out with the porous starches after being subjected to gelatinization opens new opportunities to obtain hydrogels with diverse structural and functional properties

Morphological and physicochemical characterization of porous starches obtained from different botanical sources and amylolytic enzymes

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.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R) and the European Regional Development Fund (FEDER). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Performance of Granular Starch with Controlled Pore Size during Hydrolysis with Digestive Enzymes

Studies on porous starch have been directed to explore different industrial applications as bio-adsorbents of a variety of compounds. However, the analysis of starch digestibility is essential for food application. The objective of this study was to determine the impact of porous structure on in vitro starch digestibility. Porous starches were obtained using a range of concentrations of amyloglucosidase (AMG), α-amylase (AM), cyclodextrin-glycosyltransferase (CGTase) or branching enzyme (BE). Porous starches exhibited major content of digestible starch (DS) that increased with the intensity of the enzymatic treatment, and very low amount of resistant starch (RS). Porous starches behaved differently during in vitro hydrolysis depending on their enzymatic treatment. AMG was the unique treatment that increased the digestive amylolysis and estimated glycemic index, whereas AM, CGTase and BE reduced them. A significant relationship was found between the pore size and the severity of the amylolysis, suggesting that a specific pore size is required for the accessibility of the digestive amylase. Therefore, pore size in the starch surface was a limiting factor for digestion of starch granules.Authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R) and the European Regional Development Fund (FEDER). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Influence of the Use of Hydrocolloids in the Development of Gluten-Free Breads from Colocasia esculenta Flour

Colocasia esculenta represents an alternative non-gluten ingredient due to its healthy properties. The objective of this study was to explore the breadmaking potential of Colocasia spp. cormel flour combined with hydrocolloids (hydroxypropyl methylcellulose, xanthan gum, guar gum). A total of three formulations were tested. Breads were characterized by assessing their technological qualities: moisture, specific volume, volume, hardness and weight loss. The quality parameters were similar to other gluten-free breads. Overall, Colocasia spp. flour can be used to produce gluten-free breads with similar technological quality parameters than those previously reported with common gluten-free flours

Effect of Bread Structure and In Vitro Oral Processing Methods in Bolus Disintegration and Glycemic Index

The growing interest in controlling the glycemic index of starchy-rich food has encouraged research about the role of the physical structure of food. The aim of this research was to understand the impact of the structure and the in vitro oral processing methods on bolus behavior and starch hydrolysis of wheat bread. Two different bread structures (loaf bread and bread roll) were obtained using different shaping methods. Starch hydrolysis during in vitro oro-gastro-intestinal digestion using the INFOGEST protocol was analyzed and oral processing was simulated by applying two different disintegration processes (basic homogenizer, crystal balls). The bread structure, and thus the shaping method during breadmaking, significantly affected the bolus particle size during all digestion stages. The different in vitro oral processing methods affected the bolus particle sizes after the oral phase in both breads, but they affected the particle size distribution after the gastric and intestinal phase only in the case of loaf bread. Aggregates were observed in the gastric phase, which were significantly reduced in the intestinal phase. When simulated oral processing with crystal balls led to bigger particle size distribution, bread rolls presented the highest in vitro starch hydrolysis. The type of in vitro oral processing allowed discrimination of the performance of the structures of the two breads during starch hydrolysis. Overall, crumb structure significantly affected texture properties, but also had a significant impact on particle size during digestion and starch digestibility.Authors acknowledge the financial support of the Spanish Ministry of Science, Innovation and Universities (Project RTI2018-095919-B-C21) and the European Regional Development Fund (FEDER) and Generalitat Valenciana (Project Prometeo 2017/189).Peer reviewe

Development of gluten free breads from Colocasia esculenta flour blended with hydrocolloids and enzymes

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.Authors acknowledge the financial support of the Spanish Ministry of Science, Innovation and Universities (AGL2014-52928-C2-1, RTI2018-095919-B-C21), and the European Regional Development Fund and Generalitat Valenciana (Project Prometeo 2017/189).Peer reviewe

Inulin enrichment of gluten free breads: Interaction between inulin and yeast

Inulin can improve the nutritional quality of gluten free (GF) bread and have a prebiotic activity. However, breadmaking might frustrate the enrichments efforts due to inulin loss. In this study we aimed at studying the inulin enrichment of GF bread. Two different yeasts [having normal (Y1) or reduced (Y2) invertase activity] were used to leaven the breads enriched with five marketed inulins, which differed for the degree of polymerization (DP) and the manufacturer. Inulin replaced 10% of the rice flour and had low, intermediate or high DP, which ranged from 2 to 20; ≈20; ≥20, respectively. Fructan hydrolysis occurred during leavening of Y1-GF breads, reaching losses up to 40% after baking, depending on the diverse DP of the inulin-forming fructans. Inulin loss was less relevant in Y2-GF breads (up to 5% after baking) than Y1-GF breads. Crumb texture was not negatively influenced by inulin presence, even if this was high (e.g., Y2-GF breads). Information collected within this study may provide further insight to better optimize a GF bread formulation in view of inulin enrichment.Authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER) and Generalitat Valenciana (Prometeo 2017/189).Peer reviewe

Use of flour from cormels of Xanthosoma sagittifolium (L.) Schott and Colocasia esculenta (L.) Schott to develop pastes foods: Physico-chemical, functional and nutritional characterization

The corms of cocoyams, specifically Colocasia esculenta (L.) Schott and Xanthosoma sagittifolium (L.) Schott are usually consumed as pastes. Nevertheless, the secondary corms, also named cormels, are not fully exploited. In this study, the chemical composition and functional properties of cormels from different botanical sources were evaluated, and the digestibility of the resulting pastes investigated. Colocasia spp. flour contained significantly higher protein (10.32% vs 9.65%), ash (5.65% vs 5.05%) and oxalates (0.32% vs 0.22%) content, and exhibited lower Amylab gel strength (773 g vs 1040 g) than Xanthosoma spp. flour. In the resulting pastes, micrographs revealed that starch gelatinization depended on cocoyam variety. Indeed, the very tight and closed microstructure of pastes containing Colocasia spp. flour led them to better stability during storage with lower syneresis. Lower protein digestibility was obtained in Colocasia spp. gels (67.56% vs 70.91%), but they showed faster (higher k) in vitro starch hydrolysis (0.0140 vs 0.0050) with lower estimated glycemic index (61.29 vs 65.84) than Xanthosoma spp. gels. The present findings offer ways to develop cocoyam based foods by using cormels, enhancing the applicability of cocoyams.Financial support of the Spanish Ministry of Science, Innovation and Universities (RTI2018-095919-B-C21), and the European Regional Development Fund and Generalitat Valenciana (Project Prometeo 2017/189).Peer reviewe

Thermal stabilization of probiotics by adsorption onto porous starches

Industrial processing factors, such as temperature, compromise the viability of probiotic cells. Objective was to develop a system to thermally stabilize probiotic bacteria based on porous starches and using biopolymers as coating materials (gelatinized starch, guar gum and xanthan gum). Porous starches from corn and rice starches, having controlled number and size of porous were used as supporting material. Scanning electron microscopy confirmed the adsorption of the microorganism, leading microcapsules with corn starch but aggregates with rice starch. Surface pores of rice starch increased the encapsulation yield of rice starch around 10%, but that effect was not observed in porous corn starch. The highest encapsulation yield was obtained with porous starches coated with gelatinized starch, which ranged from 92 to 100%. Microencapsulates made with porous starches with small pores, like the ones obtained with α-amylase, and coated with gelatinized starch resulted in the highest thermal resistance at 55 °C.Authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), the European Regional Development Fund (FEDER) and Generalitat Valenciana (Prometeo 2017/189). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe