Influence of bread structure on human oral processing

Influence of baking time and formulation of part-baked wheat sourdough bread on the physical characteristics, sensory quality, glycaemic index and appetite sensations

Raw materials and process parameters in bread production can modulate the glycemic index, which on itself has been linked with provision of better hunger satisfaction and maintaining better satiation. The objective of this research was to investigate if using unrefined wheat flour or the addition of intact cereals in formulation or alternating the baking time would have an effect on physical characteristics, sensory quality, glycaemic index and appetite sensations in wheat sourdough bread. In the study, three types of commercial part-baked frozen sourdough bread, baked to the final baking for two different times (long and short baking time) were used. A randomized controlled crossover trial was performed with 10 healthy adults who consumed sufficient quantity of bread to ingest 50 g available carbohydrates. Participants self-reported appetite sensations (desire to eat, hunger, fullness, satisfaction, appetite) on a 10 cm visual analog scale (VAS) scale in a course of 180 min. In addition, bread products were subjected to overall acceptability and different sensory attributes were examined on JAR "just about right" scale. Different bread formulations (refined flour, unrefined wheat flour, cereal flour or intact cereals) and different length of baking time significantly influenced (p < 0.005) physical, textural and sensory features of products. The alternation of aforementioned parameters decreased the glycemic index, but not significantly (p > 0.005). No correlation was found between lower GI, satiety and satiation. Liking score and incremental area under the curve (iAUC) of satiety and satiation were calculated as highest in sourdough bread with added cereals.

Perspective on oral processing of plant-based beverages

Around the world, the market for plant-derived beverages is one of the fastest-expanding segments in the functional and specialty beverage areas of newer food product development. Consumers are increasingly likely to choose alternatives to bovine beverages due to factors including lactose intolerance, hypercholesterolemia prevalence, allergies to bovine beverages, and preference for vegan diets that contain functionally active ingredients with health-promoting characteristics. Due to health, ecological, and ethical concerns, many customers are interested in reducing their usage of animal products like bovine milk. A variety of plant-based beverage substitutes are being created by the food sector as a result. To create viable alternatives, it is first necessary to provide an overview of the chemical composition, structure, features, and nutritional attributes of ordinary bovine milk. Sensory acceptability in the case of substitutes for beverages made from legumes is a significant barrier to their widespread acceptance, and thus saliva acts as a sophisticated fluid that serves a variety of purposes in the cavity of the mouth. Designing and producing next-generation plant-based beverages that mimic the physicochemical and functional qualities of conventional bovine-based beverages is gaining popularity, and many of these products can be thought of as colloidal materials that contain the particles or polymers that give them their unique qualities NG-PB foods can have a wide range of rheological qualities, such as fluids with low viscosity (such as plant-based beverages), high-viscosity liquids (like creams), soft liquids (like yogurt), as well as hard solids (such as some cheeses).

Effect of modifying pumpkin preparation on oral processing of breads

There is an increasing demand for texture sensations of bread during mastication, with reformulation being needed. This study investigated how bread structure influences oral processing behavior and texture perception. Variations in bread structure were created by manipulating ingredient additions, including pumpkin content and pumpkin processing methods. Results indicated that the physical, chemical, and structural properties drove the oral processing behaviors, and texture sensations were highly correlated with bolus properties. At the beginning and middle of the mastication, bolus from breads with low pumpkin-content required more saliva and exhibited greater hardness, lower adhesiveness, and a higher proportion of small-piece particles than the bolus from high pumpkin-content breads. Bolus from pumpkin pulp breads required more saliva, and was softer, stickier, and generated particles with a lower degree of degradation than the bolus from pumpkin puree breads. However, at the end period, the bolus properties tended to change to similar values. Low pumpkin content breads were initially perceived chewy, whereas high pumpkin content, soft. The dominance rate for soft sensation was higher and lasted longer in breads with pumpkin puree than in breads with pumpkin pulp. Finally, six bread samples were all perceived as hydrated, sticky, and crumbly. This study contributes to a better understanding of the impact of reformulation on oral behavior and sensory properties.

Photosensitization can be an effective risk-reduction strategy against the post-baking mold spoilage of bread

Photosensitization was developed as a risk-reduction strategy against the contamination by environmental mold spores during the bread cooling phase. Two food-grade photosensitizers -chlorophyllin (CHL) and riboflavin (RBF), were used to evaluate the effect of visible (blue) LED illumination against three common bread spoilage molds. Aided by CHL, 405 nm LEDs inactivated Rhizopus stolonifer and Penicillium expansum by 77.4 ± 3.3% and 52.1 ± 7.3% respectively in 30 min on dichloran rose bengal chloramphenicol agar. These reductions were much higher than the corresponding reductions observed with food-grade RBF and 445 nm LEDs - 22.8 ± 3.2% and 45.5 ± 5.9%, indicating that CHL-based photosensitization was more effective as an intervention than RBF-based photosensitization. When the three molds were illuminated on bread after spraying CHL and spot-inoculation, their populations were reduced by 51-58%. CHL-based photosensitization was observed to retain the texture and moisture of the bread samples, but had a statistically significant impact on their colour. The results of this study suggest that CHL-based photosensitization can be developed as a risk reduction method to prevent the spoilage of bread.

Effect of salivary fluid characteristics on the physical features of in vitro bread bolus: From the absence of saliva to artificially simulated hypersalivation

Saliva facilitates food oral processing, bolus formation, swallowing, and sensory perception, in addition to contributing to oral health and phonation. Ageing, health affections, and polymedication are among many causes altering salivary production, modifying the mastication process, the food impregnation ratio, and in turn altering the characteristics of the bolus, swallowing, and digestion. In this in vitro work, using the AM2 masticator apparatus, which replicates the mechanical actions taking place while chewing solid foods and produces realistic food bolus in various oral conditions, we investigated the effect of salivary fluid characteristics, i.e., composition, quantity (from absence to hypersalivation), temperature, and enzymatic action, on the physical characteristics (i.e., particle size distribution (PSD), bolus mass, salivary fluid content) of in vitro boluses of Traditional French baguette. A ready-to-swallow bolus of baguette displayed on average a d50 value (median particle size by mass) of 4.1 ± 0.4 mm, with saliva fluid constituting ∼ 35 % of the final bolus mass. The absence of saliva in mouth led to a deficient oral processing, forming bread boluses constituted by extremely big particles (ca. 80 % of particles had a size > 7.1 mm) that likely cannot be swallowed safely. On the contrary, an excess of saliva favoured an excessive breaking down of bread, leading to bread boluses constituted by smaller particles than those formed under healthy salivary conditions (d50 decreased from 4.1 mm to 3.1 mm), having a higher salivary fluid content (+10 %). On the other hand, the salivary fluid temperature did not affect PSD, d50, bolus mass, or salivary fluid content of in vitro bread boluses, however, the addition of human salivary α-amylase did, favouring particle size reduction (d50 decreased to 2.6 mm). Therefore, beyond the correlation between bolus hydration by saliva and food properties such as hardness and moisture content, our findings indicate that the quantity of salivary fluid present in the oral cavity and the enzymatic activity of salivary α-amylase during bread mastication significantly influence both the particle size distribution and the fluid content of bread boluses, ultimately determining the physical properties of the bolus and, therefore, potentially impacting the subsequent swallowing process.

Encapsulation of carvone in chitosan nanoemulsion as edible film for preservation of slice breads against Aspergillus flavus contamination and aflatoxin B1 production

Aspergillus flavus is a common fungus causing bread spoilage by aflatoxin B1 (AFB1) production. Essential oil components are considered as effective antifungal agent; however, volatility and oxidative-instability limited their practical applications. The aim of this study was to fabricate novel chitosan nanoemulsion film incorporating carvone (carvone-Ne) for protection of bread slices against A. flavus and AFB1 contamination in storage conditions. The nanoemulsion was characterized by SEM, DLS, XRD, and FTIR analyses accompanying with sustained delivery of carvone. The carvone-Ne displayed better inhibition of A. flavus (0.5 µL/mL) and AFB1 production (0.4 µL/mL) over unencapsulated carvone along with promising antioxidant activity (p < 0.05). Destruction of ergosterol, mitochondrial-membrane-potential, ions leakage, deformities in methylglyoxal biosynthesis, and in-silico interaction of carvone with Afl-R protein emphasized the antifungal and antiaflatoxigenic mechanisms of action. Further, in-situ preservation potentiality of Carvone-Ne in bread slices with improved gas compositions, and acceptable sensory qualities strengthen its application as innovative packaging material for food preservation.

A dynamic in vitro oral mastication system to study the oral processing behavior of soft foods

A bolus-oriented artificial oral mastication system was developed to simulate the dynamics of food mastication in the human mouth. The system consists of a chewing unit, a bolus forming unit, and provisions for the dynamic incorporation of saliva during mastication. The system performance was validated with in vivo trials (n = 25) considering time-dependent changes in particle size, textural attributes and rheological behavior of the bolus. Idli, a fermented and steamed black gram-rice-based Indian food was considered the model soft food for all trials measured in triplicates. The mastication dynamics were evaluated by analyzing bolus properties during every 3 s of mastication. Large strain shear rheology tests revealed that the viscosity of the sample decreased over time. Results of in vivo trials follow close trends in particle size and rheological behavior and have no significant change in correlation with in vitro mastication results. Similar observations were made in the half softening time of idli during mastication as determined using the relative change in hardness (hardness ratio (H_t/H₀)) values fitted to the Weibull model. Also, a model to simulate the time-dependent changes in bolus adhesiveness was developed.

Impact of wheat bran micronization on dough properties and bread quality: Part II - Quality, antioxidant and nutritional properties of bread

To investigate the impact of superfine grinding of wheat bran on bread quality, antioxidant and nutritional properties, bran with different particle sizes (coarse, D₅₀ of 362.3 μm; medium, 60.4 μm; superfine, 11.3 μm) were produced and fortified to white bread at three levels (10, 20 and 30%). At 20% fortification, compared to coarse bran, superfine bran increased the hardness and reduced the brightness of bread crumb by 56.3 and 3.30%, respectively, while it decreased bread's cell size by 10.7% and insignificantly impacted on bread's specific volume and porosity. Superfine bran retarded bread staling by 8.3% than coarse bran. It resulted in significantly better sensory attributes of bread in taste, texture and general palatability, and the fortified bread was overall acceptable (score > 6). Moreover, faster release of antioxidants (285-353% higher k), slower release of glucose (10.8% lower k), 3.76% less rapidly digestible starch, 5.65% more slowly digestible starch and 13.2% more resistant starch were found in the superfine group than the coarse one. Results demonstrated the potential of 20% fortification of superfine bran in developing fibre-enriched bread with satisfactory quality, increased antioxidant property and improved glycaemic modulation.

Guiding the formulation of soft cereal foods for the elderly population through food oral processing: Challenges and opportunities

As the elderly population is growing steadily, more age-friendly food products that allow them to cover their nutritional needs and are enjoyable need to be designed. Since their oral physiology is considerably altered, the study of Food Oral Processing has become an essential discipline in food development, as it takes into consideration the complex interactions between food structure, oral processing, physiology and perception. Cereals are staple foods in many countries, and their consumption as bakery products is popular among the elderly population. In addition, when fortified with pulse proteins, they can help meet the protein needs of seniors and help fight against sarcopenia. For these reasons, this chapter presents an overview of the various aspects involved in the oral processing and formulation of soft cereal foods, translating them into challenges and opportunities that are of relevance to the design of realistic soft cereal foods targeted for the elderly that are nutritious and sensory appealing. This review focuses on the healthy elderly population and does not intend to cover the needs of the dependent elderly suffering from chronical diseases.

Effects of anthocyanins on bread microstructure, and their combined impact on starch digestibility

Several studies have confirmed the reduction of starch digestibility with anthocyanins in food systems via mechanisms of enzyme inhibition. However, starch-polyphenol interactions may also contribute to this reduction, by modifying food microstructures and physicochemical properties of starch. The interactions among anthocyanins, starch digestibility, and food microstructures are significant to clarify the digestion processes of fortified food systems, but its interrelationship lacks clarity. Hence, we aim to evaluate the effects of black rice anthocyanin extract (BRAE) incorporation on the microstructural changes of wheat bread, in relation to overall digestibility. Overall, BRAE incorporation demonstrated a dose-dependent reduction in starch digestibility. Physicochemical analyses reflected that BRAE incorporation decreased starch gelatinisation and increased crystallinity. Microscopic imaging revealed differentiating microstructural characteristics of starch and gluten with BRAE incorporation, supporting the reduction in digestibility. Our results conclusively demonstrate that BRAE incorporation in bread suppresses starch digestibility not only through enzyme inhibition, but also food microstructural modifications.

Bread breakdown pathways during mastication: impact of wheat bran fortification

The aim of this study was to investigate the impact of wheat bran fortification on the mastication process of bread. White wheat bread (WB) and bran-fortified wheat bread (BB) were consumed by eighteen panellists. The bolus was collected at four different mastication stages and characterized by properties of hydration, particle size, and texture. The results showed that there was no difference between the two bread samples in terms of swallowable bolus moisture. BB with a harder and denser texture produced more small particles and had a slightly shorter chewing time than WB during mastication. Moreover, bolus heterogeneity (D₇₅/D₂₅) indicated a distinct difference among mastication stages and revealed different disintegration pathways between the two samples: BB bolus exhibited a monotonous particle size reduction during mastication with reducing D₅₀ and D₇₅/D₂₅; whereas, WB displayed a combination pattern of disintegration and agglomeration featuring relatively steady D₅₀ and fluctuating D₇₅/D₂₅. It was concluded that bran fortification changed the bread breakdown pathways in terms of bread disintegration and bolus formation during the mastication process. This information offers new guidelines for fortifying innovative materials to manufacture foods specifically targeted for health.

Mastication of crisp bread: Role of bread texture and structure on texture perception

Texture and structure of breads have been related to oral processing (FOP) performance and sensory perceptions, but moisture content might play a significant role. To evaluate the real impact of breads texture and structure, eliminating the possible role of moisture content, different toasted breads were investigated. Four commercial toasted sliced breads (white bread -WHB-, whole wheat bread -WWB-, non-added sugar bread -NSU-, non-added salt bread -NSA-) with similar ingredients but different texture and structure were selected. Texture and structure were instrumentally and sensory evaluated, besides FOP (total chewing time, number of chews until swallowing, chewing frequency, and mouthful) and bolus properties (moisture, saliva to bread ratio, hardness, adhesiveness, and cohesiveness). Toasted breads showed significant differences in hardness, cutting strength, and porosity, but panelists did not discriminate among them. FOP results indicated that harder samples (NSU) required longer mastication and a number of chews, and open crumb structures (WWB, WHB) with higher cell areas required less mastication. Also, bolus characteristics were affected by bread types, and bread with lower crumb hardness (WHB) produced more cohesive bolus. Having toasted breads allowed to eliminate possible influence of moisture content differences on sensory perception, mouthful and bolus water incorporation during mastication.

Glycaemic potency reduction by coarse grain structure in breads is largely eliminated during normal ingestion

The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB – reference), (2) 75 % of kibbled purple wheat in 25 % white bread matrix (PB) and (3) a 1:1 mixture of 37·5 % kibbled soya beans and 37·5 % of kibble purple wheat in 25 % white bread matrix (SPB). Each bread was ingested in three forms: unchewed (U), as customarily consumed (C) and homogenised (H). Twelve participants ingested 40 g available carbohydrate portions of each bread in each form, with post-prandial blood glucose measured over 120 min. Glycaemic responses to WB were the same regardless of its form when ingested. Unchewed PB had significantly less glycaemic effect than WB, whereas the C and H forms were similar to WB. Based on a glycaemic index (GI) of 70 for WB, the GI values for the C, U and H breads, respectively, were WB: 70·0, 70 and 70, PB: 75, 42 and 61, SPB: 57, 48 and 55 (%) (Least significant difference = 17·43, P < 0·05, bold numbers significantly different from WB). The similar glycaemic response to the H and C forms of the breads, and their difference from the U form, showed that the glycaemia-moderating effect of grain structure on starch digestion was lost during customary ingestion of bread. We conclude that the kibbled-grain structure may not effectively retard starch digestion in breads as normally consumed because it is largely eliminated by ingestive processes including chewing.

Understanding the oral processing of solid foods: Insights from food structure

Understanding the relationship between the structure of solid foods and their oral processing is paramount for enhancing features such as texture and taste and for improving health-related factors such as management of body weight or dysphagia. This paper discusses the main aspects of the oral processing of solid foods across different categories: (1) oral physiology related to chewing, (2) in-mouth food transformation, (3) texture perception, and (4) taste perception, and emphasis is placed on unveiling the underlying mechanisms of how food structure influences the oral processing of solid foods; this is exemplified by comparing the chewing behaviors for a number of representative solid foods. It highlights that modification of the texture/taste of food based on food structure design opens up the possibility for the development of food products that can be applied in the management of health.

Superior anti-infective potential of eugenol-casein nanoparticles combined with polyethylene glycol against Colletotrichum musae infections

The aim of this study was to improve the stability of eugenol-casein nanoparticles (EL-CS-NPs) through polyethylene glycol (PEG) modification. The results show that modifying the EL-CS-NPs with PEG after loading with eugenol (EL) gives PEG-EL-CS-NPs, with increased stability. The NPs modified with higher-molecular-weight PEG showed better stability. A CS/PEG ratio of 200 : 1 (w/w) yielded the NPs with the best stability. A PEG20 K-EL-CS-NP dispersion remained stable in cold storage for over one year, and also exhibited stronger inhibitory effects against Colletotrichum musae inoculated on bananas than an EL-CS-NP dispersion, since it showed more prolonged sustained release of EL than the EL-CS-NP dispersion. Lyophilized PEG20 K-EL-CS-NP powder showed better effectiveness against mold on bread than lyophilized EL-CS-NPs powder. Using PEG to modify CS-NPs shows potential for improving the stability of CS-NPs loaded with hydrophobic substances for delivery in the fields of food and agriculture.

Effect of Barley Antifreeze Protein on Dough and Bread during Freezing and Freeze-Thaw Cycles

In order to verify the cryoprotective effect of an antifreeze protein (BaAFP-1) obtained from barley on bread dough, the effect of BaAFP-1 on the rheological properties, microstructure, fermentation, and baking performance including the proofing time and the specific volume of bread dough and bread crumb properties during freezing treatment and freeze-thaw cycles were analysed. BaAFP-1 reduced the rate of decrease in storage modulus and loss modulus values during freezing treatment and freeze-thaw cycles. It influenced the formation and the shape of ice formed during freezing and inhibited ice recrystallization during freeze-thaw. BaAFP-1 maintained gas production ability and gas retention properties, protected gluten network and the yeast cells from deterioration caused by ice formation and ice crystals recrystallisation in dough samples during freezing treatment and freeze-thaw treatment. It slow down the increase rate of hardness of bread crumb. The average area of pores in bread crumbs decreased significantly (p < 0.05) as the total number of pores increased (p < 0.05), and the addition of BaAFP-1 inhibited this deterioration. These results confirmed the cryoprotective activity of BaAFP-1 in bread dough during freezing treatment and freeze-thaw cycles.

Effects of dry heat treatment temperature on the structure of wheat flour and starch in vitro digestibility of bread

The effects of the dry heat treatment (DHT) temperature (20, 50, 100, 150, 200 °C) on the structure of wheat flour and on the texture and in vitro starch digestibility of breads were investigated. X-ray diffraction and FTIR showed that increasing temperatures produced reduction of the hydrated starch structures, increased crystallinity and molecular order of starch chains, and had important effects on the gluten secondary structure. High treatment temperatures produced significant reductions in rapidly digestible starch (RDS) (53.21% at 20 °C, 22.24% at 200 °C), and the slowly digestible starch fraction tended to increase (26.12% at 20 °C, 31.48% at 200 °C). On the other hand, bread hardness showed a significant increase from 11.25 N at 20 °C to 49.53 N at 200 °C, the latter value being similar to that reported for bread crusts. Principal component analysis results showed that the flour and bread characteristics were drastically changed by the DHT, with 100 °C representing a critical temperature. Below 100 °C, breads showed textural characteristics close to that of the control bread, with reduced RDS fractions, while at temperatures above 100 °C, hardness was boosted.

Characterization of the dynamic texture perception and the impact factors on the bolus texture changes during oral processing

The purpose of this work was to characterize the dynamic texture perception and study the mechanisms occurring in bolus from chewing to swallowing during white bread oral processing. Results indicated that the microstructural and chemical composition properties determined the oral processing behaviors. At the initial stage of oral processing, the roughness, hardness, and dryness perception were the dominant attributes. At the end of oral processing the adhesiveness and softness perception were dominant, which correlated to the higher bolus water content and adhesive properties. The softness and adhesiveness perception were the key factors that trigger swallowing. In vitro artificial mastication experiments confirmed that mucin rapidly increased the adhesive force of bolus at the initial stage of oral processing, whereas α-amylase gradually increased the adhesive force. These results can help to better understand the dynamic texture perception and its change mechanisms during oral processing.

Destructuring and restructuring of foods during gastric digestion

All foods harbor unique length scale-dependent structural features that can influence the release, transport, and utilization of macro- or micronutrients in the human gastrointestinal tract. In this regard, food destructuring and restructuring processes during gastric passage significantly influence downstream nutrient assimilation and feelings of satiety. This review begins with a synopsis of the effects of oral processing on food structure. Then, stomach-centric factors that contribute to the efficacy of gastric digestion are discussed, and exemplified by comparing the intragastric de- and restructuring of a number of common foods. The mechanisms of how intragastric structuring influences gastric emptying and its relationship to human satiety are then discussed. Finally, recently developed, non-destructive instrumental approaches used to quantitively and qualitatively characterize food behavior during gastric destructuring and restructuring are described.

Reducing the glycemic impact of carbohydrates on foods and meals: Strategies for the food industry and consumers with special focus on Asia

Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate-rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co-ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.

Whole-wheat flour particle size influences dough properties, bread structure and in vitro starch digestibility

Whole-wheat flour (WWF) particle size is critical to dough properties, bread quality, and in vitro starch digestibility of bread.

Evaluation of texture of cheese by-products incorporated bread

Abstract This work aimed to develop new breads incorporating whey residue, “sorelho”, obtained from ewe’s milk after the production of Serra da Estrela Cheese. For this, we baked three types of bread: wheat bread (control sample), bread incorporating sorelho, and another version containing additional nutritional elements. The texture was evaluated with a texturometer, using compression and perforation tests. Results showed that sorelho can be successfully incorporated in bread. The best product was the bread with sorelho plus improved nutrition, which presented good textural characteristics during a period of 24 hours. This trend was observed for all properties evaluated: hardness, chewiness, resilience, cohesiveness, springiness (compression test) and external firmness, inner firmness, stickiness, adhesiveness (perforation test). Finally, factor analysis showed: FACTOR 1 – compression textural properties; FACTOR 2 – perforation firmness properties and FACTOR 3 – perforation adhering properties, which in total explained approximately 81% of total variance.

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.

Potential Impact of Oat Ingredient Type on Oral Fragmentation of Biscuits and Oro-Digestibility of Starch-An In Vitro Approach

The aim of the present study was to determine how variation in the biscuit matrix affects both the degree of in vitro fragmentation and the starch hydrolysis that occurs during the oral phase of digestion. Using three different oat ingredient types (oat flour, small flakes, and big flakes) and baking powder (or none), six biscuits with different matrices were obtained. The instrumental texture (force and sound measurements) of the biscuits was analyzed. The samples were then subjected to in vitro fragmentation. The particle size distribution and in vitro oral starch hydrolysis over time of the fragmented samples were evaluated. The results showed that the samples presented different fragmentation patterns, mainly depending on the oat ingredient type, which could be related to their differences in texture. The biscuits made with oat flour were harder, had a more compact matrix and showed more irregular fragmentation and a higher percentage area of small particles than those made with big oat flakes, which were more fragile and crumbly. The highest degree of starch hydrolysis corresponded to the biscuits made with flour. Conclusions: Differences in the mechanical properties of the biscuit matrix, in this case due to differences in the oat ingredient, play a role in the in vitro fragmentation pattern of biscuits and in the oral phase of starch hydrolysis.

In vitro digestion of bread: How is it influenced by the bolus characteristics?

This study aimed to understand the impact of in vitro oral processing methods on bolus formation and the kinetics of starch hydrolysis of refined white bread during in vitro gastrointestinal digestion. Four in vitro oral processing methods (i.e., cut, cut-and-pestle, blend, and grind) were performed at two levels of disintegration (less and more intensive) and compared with human mastication. Boluses prepared using the in vitro methods had a larger particle size (20-69 mm² vs. 14 mm² ), a higher moisture content (64-68% vs. 47%), a softer texture (1.3-2.3 N vs. 6.3 N) and a less adhesive surface (0.3-1.0 vs. 1.6 N•s) as compared to the in vivo masticated ones. Moreover, in vitro prepared blouses were digested more rapidly than in vivo masticated ones during the stimulated intestinal digestion from 150 min onward, with a higher hydrolysis rate (0.011-0.012 mg/mL • min vs. 0.010 mg/mL • min) and a higher equilibrium concentration of reducing sugar (5.5-6.3 mg/mL vs. 4.9 mg/mL). Among all the in vitro methods, the blending and grinding methods produced boluses that most closely resemble the in vivo masticated ones in terms of their physical characteristics. The blending method also produced boluses having the highest amount of reducing sugar released (6.32 mg/mL). The amount of reducing sugar present in the PBS buffer outside the dialysis tube might be controlled by the diffusion efficiency at the beginning of the digestion (≤120 min) and then be largely influenced by the particle size of the bolus in the latter stage of the digestion. PRACTICAL APPLICATION: Studying the in vitro starch amyloysis is valuable for predicting the postprandial glycemic potential of starchy food. This work provides novel insights on the role of in vitro oral processing in the prediction of the glycemic potential of carbohydrate-rich staple food. Blending method is recommended because of its ability to produce boluses with similar physical characteristics as the in vivo masticated boluses. But the excessive structural breakdown occurred during blending also resulted in a higher enzymatic accessibility and a higher rate of starch digestion. Further study is needed to propose a new in vitro method that stimulates multiple actions occurred during mastication (cutting, grinding, and shearing), in order to match both physical properties and digestion profiles. Moreover, the amount of artificial saliva added should be adjusted according to the specific type of food.

Appropriate parboiling steaming time at atmospheric pressure and variety to produce rice with weak digestive properties

Consumers with diabetes mellitus have shown interest in products with low postprandial glucose. To produce rice for this group of consumers, the effect of parboiling steaming time (0, 5, 15, 25, 35, and 45 min) and variety (NERICA1, NERICA7, WITA4, and IR841) on resistant, damaged starch fractions and glycemic response in rats was investigated. Resistant and damaged starch fractions were influenced by variety and steaming time but this was not the case for glycemic index. Nonparboiled NERICA7 and NERICA7 steamed for 25 min recorded the highest (10.07%) and lowest (2.49%) resistant starch fraction, respectively. Resistant starch correlated negatively with protein and sodium and positively with lipids. Damaged starch was high for WITA4 steamed for 45 min (26.80%) and low for nonparboiled NERICA1 (6.59%). Damaged starch correlated positively with lipid content and negatively with ash and total starch content. NERICA7 steamed for 35 min recorded the lowest postprandial glucose level 30 min after feeding (0.16 g/L), while WITA4 steamed for 15, 25, and 35 min and nonparboiled NERICA7 recorded higher levels (0.76, 0.91, 0.84, and 0.76 g/L, respectively). NERICA7 steamed for 35 min recorded both low glycemic and weak digestive properties because the glycemic index was lowest 120 min and increased steadily up to 180 min after feeding. We conclude that the digestive properties of rice depend both on the intrinsic properties of the variety and the parboiling steaming time.

Taguchi-generalized regression neural network micro-screening for physical and sensory characteristics of bread

Generalized regression neural networks (GRNN) may act as crowdsourcing cognitive agents to screen small, dense and complex datasets. The concurrent screening and optimization of several complex physical and sensory traits of bread is developed using a structured Taguchi-type micro-mining technique. A novel product outlook is offered to industrial operations to cover separate aspects of smart product design, engineering and marketing. Four controlling factors were selected to be modulated directly on a modern production line: 1) the dough weight, 2) the proofing time, 3) the baking time, and 4) the oven zone temperatures. Concentrated experimental recipes were programmed using the Taguchi-type L9(34) OA-sampler to detect potentially non-linear multi-response tendencies. The fused behavior of the master-ranked bread characteristics behavior was smart sampled with GRNN-crowdsourcing and robust analysis. It was found that the combination of the oven zone temperatures to play a highly influential role in all investigated scenarios. Moreover, the oven zone temperatures and the dough weight appeared to be instrumental when attempting to synchronously adjusting all four physical characteristics. The optimal oven-zone temperature setting for concurrent screening-and-optimization was found to be 270-240 °C. The optimized (median) responses for loaf weight, moisture, height, width, color, flavor, crumb structure, softness, and elasticity are: 782 g, 34.8 %, 9.36 cm, 10.41 cm, 6.6, 7.2, 7.6, 7.3, and 7.0, respectively.

Relationships of oral comfort perception and bolus properties in the elderly with salivary flow rate and oral health status for two soft cereal foods

The aim of this study was to investigate food oral processing and bolus formation in the elderly population, and their relationship with the perception of oral comfort, for two soft cereal products of different composition: sponge-cake and brioche. Twenty subjects aged 65 and over participated in the study. They were classified in two groups according to dental status (poor vs. satisfactory) and presented various stimulated salivary flow rate (SSF) in each group. Food bolus properties (hydration ratio and apparent viscosity) were characterized after three chewing stages for both groups. Results showed that chewing duration did not depend on food product but rather on physiology: subjects with a poor dental status had a shorter chewing duration. For each chewing stage, sponge-cake boli showed a higher hydration ratio than brioche boli, which showed higher apparent viscosity. For sponge-cake, perception of oral comfort was primarily driven by SSF rate, irrespective of the dental status. In the case of brioche, oral comfort was also partially explained by SSF in the case of subjects with poor dental status. This result suggests that perception of oral comfort in brioche could be driven by product related attributes rather than oral health. For both foods, a phenomenological model of bolus viscosity as a function of stimulated salivary flow and chewing duration was proposed.