The effects of fermentation time on sourdough bread: An analysis of texture profile, starch digestion rate, and protein hydrolysis rate.

To ensure the best quality bread, it is important to consider the speed of digestion of starch and proteins, as well as how time fermentation and storage time influence the rate of starch digestion and the texture of the bread. This study compared the effect of fermentation time and days of storage on the texture, physicochemical, protein and starch digestibility of sourdough bread. Texture profile analysis showed that the fermentation time in recently baked sourdough bread affects hardness, chewiness, and springiness. The electrophoretic profile showed a decrease in band thickness with increase in fermentation time, consistent with a higher percentage of protein digestion. While fermentation time did not significantly affect rapidly digestible starch (RDS) and slowly digestible starch (SDS), storage time resulted in a decrease in RDS and an increase in SDS. Sourdough breads had higher levels of resistant starch (RS). The digestibility characteristics of protein and starch, as well as texture properties, are significantly influenced by fermentation and storage time. The evidence suggests that sourdough bread has the potential to improve the digestion of protein and to effectively regulate the glycemic response, which is due to its higher levels of SDS and RS.

Cochayuyo (Durvillaea incurvata) Extracts: Their Impact on Starch Breakdown and Antioxidant Activity in Pasta during In Vitro Digestion.

Seaweeds, notably cochayuyo (Durvillaea incurvata), are recognized for their rich macro- and micronutrient content, along with their inhibitory effects on the α-glucosidase enzyme. The present study aims to evaluate the effectiveness of this inhibition in actual starchy food products under in vitro gastrointestinal conditions. This study utilized freeze-dried cochayuyo, extracted using hot pressurized liquid extraction with 50% ethanol at 120 °C and 1500 psi. The inhibition mechanism of α-glucosidase was determined, and the polyphenol composition of the extract was analyzed using Ultra-High-Performance Liquid Chromatography. This study further evaluated the extract's impact on starch digestibility, total phenolic content, and antioxidant capacity in pasta (noodles) as representative starchy food under gastrointestinal conditions. The results indicate that the α-glucosidase inhibition mechanism is of mixed type. Phenolic compounds, primarily tetraphloroethol, could contribute to this anti-enzymatic activity. The extract was observed to decrease starch digestibility, indicated by a lower rate constant (0.0158 vs. 0.0261 min-1) and digested starch at an infinite time (77.4 vs. 80.5 g/100 g). A significant increase (~1200 vs. ~390 µmol TROLOX/100 g) in antioxidant activity was also noted during digestion when the extract was used. Thus, this study suggests that the cochayuyo extract can reduce starch digestion and enhance antioxidant capacity under gastrointestinal conditions.

Flint corn silage management: influence of maturity stage, inoculation with Lentilactobacillus buchneri, and storage time on fermentation pattern, aerobic stability, and nutritional characteristics.

Introduction: High quality corn silage depends on factors such as corn type, stage of crop development at harvest time, fermentation time, in addition to use or not of inoculants. This study aimed to investigate the impact of maturity stage, bacterial inoculation, and storage time on fermentation, aerobic stability, and nutritional characteristics of flint corn silage and their implications for corn silage management. Methods: A flint corn hybrid was harvested very early, early, and medium (at 250, 300 and 350 g dry matter (DM)/kg as fed, respectively) and ensiled in mini-silos without (control) or with Lentilactobacillus buchneri CNCM I-4323 at 1 × 105 cfu/g for 120, 240 and 360 d to investigate how these factors interact with each other. Results and discussion: There was only a small increase (7 g/kg starch; p = 0.003) in starch digestibility (starch-D) in the silages stored for 360 d when compared to that stored for 240 d, but with no difference for 120 d. Despite the reduced starch-D (526 vs. 694 g/kg starch; p < 0.001), silages produced from medium harvest had higher (p < 0.001) starch content (317 vs. 137 g/kg DM) and higher amount of digestible starch (169 vs. 98.5 g/kg DM; p < 0.001) compared to very early harvest. The 2-way interactions (inoculation × storage time and maturity × storage time) showed that inoculation of corn silage with L. buchneri increased (p < 0.001) the aerobic stability, and that more mature crop silage had higher aerobic stability (140 h; p = 0.036) than the others (118 and 48.5 h for those silages from very early and early harvest). Conclusion: The storage for a longer time (>120 d) with the goal of increasing silage digestibility did not occur. Harvesting whole-crop flint corn with 300 to 350 g/kg DM is desirable to have higher DM yield and starch accumulation. Inoculation with L. buchneri is recommended to preserve the silage against aerobic deterioration. This study has shown the importance of harvesting flint corn at the right time, and the need for inoculation with L. buchneri to ensure greater yield, starch accumulation, and silage preservation, if 120 days of storage are not exceeded.

Inhibitory effect of Mexican oregano (Lippia graveolens Kunth) extracts on digestive enzymes in vitro, and beneficial impact on carbohydrates and lipids absorption in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Although Mexican oregano inhibits digestive enzymes in vitro its effect on the absorption of carbohydrates and lipids in vivo has not been addressed. AIM OF THE STUDY: Assess the effect of Mexican oregano (Lippia graveolens Kunth) on carbohydrates and lipids absorption in vivo. The antioxidant activity also was investigated. MATERIALS AND METHODS: Enzymatic inhibitory action of lipase, α-amylase, and α-glucosidase was evaluated in vitro. Oral lipid (OLTT) and starch tolerance tests (OSTT) were conducted with L. graveolens acetone (O-A) and ethanol (O-E) extracts (at 102 mg/kg body weight equivalent to a 1 g human doses) in male Wistar rats. The antioxidant activity was evaluated through inhibition of lipid peroxidation and scavenging radical. RESULTS: Both extracts exhibited higher inhibitory median concentration (IC50) of lipase activity (1.9 µg/µL for O-E and 1.8 µg/µL for O-A) than the positive control (Orlistat) (0.07 µg/µL). The IC50 of α-amylase was higher (41.8 µg/µL for O-E and 25.2 µg/µL for O-A) than the Acarbose (2.5 µg/µL); while α-glucosidase results showed not statistically differences between groups (∼1.7 µg/µL). The OLTT results showed that both extracts significantly reduced serum triglycerides (∼147 mg/dL for O-E and ∼155 mg/dL for O-A) as compared with negative control group (only lipid load). In the OSTT, glucose levels showed a significant decrease (∼31 mg/dL for O-E and ∼17 mg/dL for O-A) than the negative control group (only starch load). About in vitro antioxidant evaluation, not statistically differences between extracts and positive control (Trolox) were observed for scavenged free radicals (∼2.0 µg/µL); whereas O-A inhibited lipid peroxidation similar to the Trolox (∼0.8 µg/µL IC50). The main chemical composition of both extracts was coumaric acid, luteolin, rutinoside, naringenin, and carvacrol. CONCLUSIONS: Both extracts reduce lipid absorption; whereas O-E decreases carbohydrate absorption in vivo. Both extracts inhibit lipid peroxidation and scavenging free radicals in vitro.

Analysis of starch digestograms using Monte Carlo simulations.

Monte Carlo dynamics were used to simulate the enzymatic starch digestion. Enzyme and starch molecules were distributed on a periodic grid and allowed to stochastically interact according to the kinetics scheme S + E â†’ P + E. Digestion of gelatinized dispersions was simulated by assuming limited mobility of starch and complete mobility of enzymes and products. The results showed that the starch conversion kinetics follows the exponential model X(t) = X∞(1 -  exp (-kHt)). On the other hand, the simulation of native granular starch digestion considered non-mobile aggregates of starch molecules hydrolyzed to products by mobile enzyme molecules. The results showed the presence of bi-phasic digestion patterns, which were linked to the transition from a regular to an irregular (fractal-like) granule morphology as a consequence of the erosion of the granule surface by the enzyme action. The simulation results were contrasted qualitatively with experimental results for gelatinized and granular starch digestion.

The inhibitory action of purple tea on in vivo starch digestion compared to other Camellia sinensis teas.

In order to contribute to improve knowledge about the actions of Camellia sinensis extracts on starch digestion, several varieties were compared. The latter were green, oolong, white, black, and purple teas. The results are hoped to contribute to our understanding of the mode of action and potency of the various tea preparations as possible adjuvants in the control of post-prandial glycemia. The extracts were prepared in way similar to their form of consumption. All extracts decreased starch digestion, but the purple tea extract was the strongest inhibitor, their inhibitory tendency started at the dose of 50 mg/kg and was already maximal with 250 mg/kg. Maltose tolerance was not significantly affected by the extracts. Glucose tolerance was not affected by purple tea, but black tea clearly diminished it; green tea presented the same tendency. Purple tea was also the strongest inhibitor of pancreatic α-amylase, followed by black tea. The green tea, oolong tea, and white tea extracts tended to stimulate the pancreatic α-amylase at low concentrations, a phenomenon that could be counterbalancing its inhibitory effect on starch digestion. Based on chemical analyses and molecular docking simulations it was concluded that for both purple and black tea extracts the most abundant active component, epigallocatechin gallate, seems also to be the main responsible for the inhibition of the pancreatic α-amylase and starch digestion. In the case of purple tea, the inhibitory activity is likely to be complemented by its content in deoxyhexoside-hexoside-containing polyphenolics, especially the kaempferol and myricetin derivatives. Polysaccharides are also contributing to some extent. Cyanidins, the compounds giving to purple tea its characteristic color, seem not to be the main responsible for its effects on starch digestion. It can be concluded that in terms of postprandial anti-hyperglycemic action purple tea presents the best perspectives among all the tea varieties tested in the present study.

Hypoglycemic and antioxidant effects of green tomato (Physalis ixocarpa Brot.) calyxes' extracts.

The aim of this study was to evaluate the hypoglycemic and antioxidant potential of green tomato (Physalis ixocarpa Brot.) calyxes' extracts. Three methods were used to obtain the extracts: maceration (M), ultrasound-assisted (US), and infusion. Regarding in vitro hypoglycemic evaluation, glucose diffusion assay and enzymatic inhibitory action of α-amylase and α-glucosidase were performed. Whereas, for in vivo assessment an oral starch tolerance test (OSTT) was tested with aqueous extracts [infusion (40 mg/kg b. wt.), maceration (M) water (98 mg/kg b. wt.), and US water (82.24 mg/kg b. wt.)] on male Wistar rats. Additionally, in vitro antioxidant activity of P. ixocarpa calyxes' was evaluated through inhibition of scavenging radical assay and lipid peroxidation. Extracts decreased the glucose diffusion in a range of 18%-56% compared with the negative control. Additionally, extracts inhibited α-amylase (above 80%) and α-glucosidase enzymes (above 90%). All groups treated with P. ixocarpa calyxes' significantly reduced the glucose levels at 120 min (infusion = 13.3%, M Water = 12.7%, and US Water = 19.4%) in comparison with the negative control, and similar levels to acarbose at 120 min (13.1%). Finally, extracts showed IC50 values in a range of 2.5-6.6 µg/µl for radical scavenging, and 118-199 µg/µl for lipid oxidation. Our results show that P. ixocarpa calyxes' extracts induce hypoglycemia and antioxidant effects in vitro and in vivo. PRACTICAL APPLICATIONS: The green tomato is usually consumed in Mexico, the United States, and Central America. This fruit grows inside a calyx, which is considered an agro-food waste. However, some regions of Latin America have a traditional medicine purpose for diabetes affections. To the best of our knowledge, there are no published data that supports its hypoglycemic action. The information provided will be useful to nutraceutical applications that allow value-added products and sustainable green tomato production.

Addition of chickpea markedly increases the indigestible carbohydrate content in semolina pasta as eaten.

BACKGROUND: There is a growing interest in increasing dietary fiber (DF) consumption because of the health benefits associated with this nutrient. Pulses are considered a good source of non-digestible carbohydrates. The aim of this study was to investigate the possibility of substituting semolina with chickpea flour to increase indigestible carbohydrate content without altering the texture of the pasta. RESULTS: Pasta was prepared by extruding semolina-chickpea blends. The protein and DF content in the cooked pasta increased with the chickpea level, with an important contribution of resistant starch (RS) to the DF values. The optimum cooking time decreased as the chickpea content increased, which was related to the degree of starch gelatinization of the raw pasta. The in vitro digestible starch content decreased with the chickpea substitution level, concomitant with the increase in RS content. In general, the texture of the chickpea-containing pasta was similar to that of semolina pasta. CONCLUSIONS: Pending acceptability studies on these pastas may grant their promotion as good fiber sources, probably helpful in the fight against obesity and diet-related non-communicable diseases. © 2020 Society of Chemical Industry.

Bioactive Polyphenols from Southern Chile Seaweed as Inhibitors of Enzymes for Starch Digestion.

The increment of non-communicable chronic diseases is a constant concern worldwide, with type-2 diabetes mellitus being one of the most common illnesses. A mechanism to avoid diabetes-related hyperglycemia is to reduce food digestion/absorption by using anti-enzymatic (functional) ingredients. This research explored the potential of six common Chilean seaweeds to obtain anti-hyperglycemic polyphenol extracts, based on their capacity to inhibit key enzymes related with starch digestion. Ethanol/water hot pressurized liquid extraction (HPLE), which is an environmentally friendly method, was studied and compared to conventional extraction with acetone. Total polyphenols (TP), antioxidant activity, cytotoxicity and inhibition capacity on α-glucosidase and α-amylase were analyzed. Results showed that the Durvillaea antarctica (cochayuyo) acetone extract had the highest TP content (6.7 ± 0.7 mg gallic acid equivalents (GAE)/g dry seaweed), while its HPLE ethanol/water extract showed the highest antioxidant activity (680.1 ± 11.6 µmol E Trolox/g dry seaweed). No extract affected cell viability significantly. Only cochayuyo produced extracts having relevant anti-enzymatic capacity on both studied enzymes, showing a much stronger inhibition to α-glucosidase (even almost 100% at 1000 µg/mL) than to α-amylase. In conclusion, from the Chilean seaweeds considered in this study, cochayuyo is the most suitable for developing functional ingredients to moderate postprandial glycemic response (starchy foods), since it showed a clear enzymatic inhibition capacity and selectivity.

Microstructure of starch-based meals with either palm or soybean oils alter in vitro starch digestibility with no major effects on glycaemic responses.

Glycaemic response (GR) to starch-based meals depends on their food composition and microstructure. We studied the effect of palm and soybean oils on the microstructure of a solid starch-oil-gluten matrix, on the starch gelatinisation and in vitro digestibility. Additionally, a pilot cross-over study was carried out to assess GR after eating gelatinised starch/gluten-based foods with the addition of either palm or soybean oil in 8 young non-diabetic female volunteers (ISRCTN39636850). Both types of foods generated similar starch gelatinisation temperature. Starch/gluten-based food with soybean oil had rougher microstructure compared to food with palm oil, showing a higher initial and lower final in vitro digestion. Administration of starch/gluten-based meals with either palm or soybean oils to volunteers show very similar postprandial glucose or insulin responses. In conclusion, differences in fatty acid composition changes food microstructure and in vitro starch digestibility, with no major effects on glycaemic responses in female volunteers.

Physicochemical characteristics, ATR-FTIR molecular interactions and in vitro starch and protein digestion of thermally-treated whole pulse flours.

Hydrothermal treatments, annealing (ANN) and heat moisture treatment (HMT) were applied to four whole pulse flours (black bean, broad bean, chickpea and lentil) with the aim to increase their slow digestible (SDS) and resistant starch (RS) fractions. In order to assess differences in their molecular interactions, they were analyzed and compared by ATR-FTIR before and after in vitro digestion. Both hydrothermal treatments promoted changes on starch granular architecture, being reflected on their thermal and pasting properties, that where positively correlated with their amylose and protein contents (R=0.96, P<0.01). Overall, the proposed hydrothermal treatments increased their SDS and RS fractions, but they had different effect on their in vitro protein digestion. The ATR-FTIR analysis of cooked flours before and after digestion showed that thermal treatments promoted new physical interactions at molecular scale between starch and proteins, that were correlated with the amount of RS fraction. The outcomes of this study could help to understand the slow digestion properties and possible interactions of the flour components in these four pulses.

Digestion of starch in a dynamic small intestinal model.

PURPOSE: The rate and extent of starch digestion have been linked with important health aspects, such as control of obesity and type-2 diabetes. In vitro techniques are often used to study digestion and simulated nutrient absorption; however, the effect of gut motility is often disregarded. The present work aims at studying fundamentals of starch digestion, e.g. the effect of viscosity on digestibility, taking into account both biochemical and engineering (gut motility) parameters. METHODS: New small intestinal model (SIM) that realistically mimics gut motility (segmentation) was used to study digestibility and simulated oligosaccharide bio accessibility of (a) model starch solutions; (b) bread formulations. First, the model was compared with the rigorously mixed stirred tank reactor (STR). Then the effects of enzyme concentration/flow rate, starch concentration, and digesta viscosity (addition of guar gum) were evaluated. RESULTS: Compared to the STR, the SIM showed presence of lag phase when no digestive processes could be detected. The effects of enzyme concentration and flow rate appeared to be marginal in the region of mass transfer limited reactions. Addition of guar gum reduced simulated glucose absorption by up to 45 % in model starch solutions and by 35 % in bread formulations, indicating the importance of chyme rheology on nutrient bioaccessibility. CONCLUSIONS: Overall, the work highlights the significance of gut motility in digestive processes and offers a powerful tool in nutritional studies that, additionally to biochemical, considers engineering aspects of digestion. The potential to modulate food digestibility and nutrient bioaccessibility by altering food formulation is indicated.

Interactions between Starch, Lipids, and Proteins in Foods: Microstructure Control for Glycemic Response Modulation.

In real food, starch is usually forming part of a matrix with lipids and proteins. However, research on this ternary system and interactions between such food components has been scarce so far. The control of food microstructure is crucial to determine the product properties, including sensorial and nutritionals ones. This paper reviews the microstructural principles of interactions between starch, lipids, and proteins in foods as well as their effect on postprandial glycemic response, considering human intrinsic differences on postprandial glycemic responses. Several lines of research support the hypothesis that foods without rapidly digestible starch will not mandatorily generate the lowest postprandial glycemic response, highlighting that the full understanding of food microstructure, which modulates starch digestion, plays a key role on food design from a nutritional viewpoint.