Sushil Dhital

Monash University (Australia) · Department of Chemical Engineering, Clayton

Lentils and mungbean proteins are under-researched compared to pea and soybean. Lentils (green, red and black-lentils), mungbean and yellow pea protein isolates were obtained by alkaline extraction (pH 9)-isoelectric precipitation (pH 4.5) and investigated for molecular and higher-order structures using complementary and novel approaches. These ext...

Proteins from the full and defatted flours of L. angustifolius cv Jurien and L. albus cv Murringo were prepared using alkaline extraction and iso-electric precipitation. Isolates were either freeze dried or spray dried or pasteurized at 75 ± 3 °C/5 min before freeze-drying. Various structural properties were investigated to elucidate the varietal a...

Lupin, an arid pulse, is gaining popularity as a super food due to its superior nutritional properties. However, it has not been considered for large scale thermal processing, e.g., canning. The present work evaluated the best time/temperature combination to hydrate lupins for canning with minimum losses of bioactive nutrients, pre-biotic fibre, an...

Future dietary protein demand will focus more on plant-based sources than animal-based products. In this scenario, legumes and pulses (lentils, beans, chickpeas, etc.) can play a crucial role as they are one of the richest sources of plant proteins with many health benefits. However, legume consumption is undermined due to the hard-to-cook (HTC) ph...

Intact cells, as the smallest unit of whole foods, were isolated from three legume crops and fermented with human faecal inoculum to elucidate the effect of food macro-nutrients compositional difference (starch, proteins and lipids) on in vitro colonic fermentation profiles. After 48 h of fermentation, the highest production of short-chain fatty ac...

Increased nutritional functionality in bread and noodles have been reported with the incorporation of high amylose wheat flour (HAWF). Here, we broaden the application of HAWF and report structure-function-nutrition relationships for tortillas prepared with 50% and 100% incorporation of HAWF. The breaking force and extensibility of the HAWF tortill...

Mol. Nutr. Food Res. 2022, 66, 2200098 DOI: 10.1002/mnfr.202200098 Human milk oligosaccharides (HMOs) are beneficial to infant gut health. In article number 2200098, Feitong Liu, Bin Zhang, and co‐workers demonstrate that the in vitro infant fecal fermentation profiles are more dependent on the initial gut microbiota composition than chemical struc...

Among the wide range of plant-based protein sources, pulse proteins stand out for their nutritional values and functional properties, together with sustainability. The global attention on soy and pea proteins, however, has overlooked other pulses. This review has explored underutilized and under-researched pulses, lentils and mungbean, by consideri...

Scope: Human milk oligosaccharides (HMOs), multifunctional glycans naturally present in human milk, are known to contribute to the infant's microbiota and immune system development. However, the molecular specificity of HMOs on microbiota and associated fermentation is not yet fully understood, and is important for the development of infant formul...

To elucidate starch structural features underlying resistant starch formation, wheat starch granules with three (A-, B- and C- type) crystalline polymorphisms and a range of amylose contents were digested in vitro. The changes in multi-level structure of digestion residues were compared. In the residues of A- and C-type starches, the molecular fine...

Gluten-free noodles, e.g. potato starch noodles, are getting popular due to the increasing population with gluten sensitivity and celiac disease. However, due to the lack of gluten network, the solid loss of potato starch noodles during cooking leads to lower textural and sensory attributes. The starch modification provides the opportunity to addre...

The popularity of high-amylose cultivars of main crops (e.g., high-amylose wheat, HAW) has been increasing because of their unique functional properties and enhanced nutritional values. In the current study, we employed the high-temperature Rapid Visco-Analyzer (HTRVA) to evaluate the performance of HAW flours and starches with an extensive range o...

The modulation of starch hydrolysis by soluble fibres has been reported in both in vitro and in vivo conditions. Several mechanisms have been put forward including increased gastric retention time, and altered gastric digesta rheology affecting overall mass transfer (enzyme, substrate and hydrolysed products). The direct inhibition of amylase activ...

This study investigated the fermentation characteristics and microbial responses of human milk oligosaccharides (HMOs) by individual Bifidobacterium longum-dominant infant fecal microbiota. Fucosylated neutral HMOs (2′-fucosyllactose, 2′-FL; 3-fucosyllactose, 3-FL), sialylated HMOs (3′-sialyllactose, 3′-SL; 6′-sialyllactose, 6′-SL), and non-fucosyl...

The consumption of foods with intact cellular structure is recognized to lower the glycemic index. Studies have focused on the gelatinization and digestibility of starch in intact cells. However, the effects of intact cells on starch retrogradation and digestibility are still unclear. Mild acid and alkali soaking were used to isolate intact potato...

Macronutrients of pulses or cereals are stored in the cotyledon or endosperm cells with protection from intact cell walls. However, pulses and cereals are generally processed into fine particles during food production. For example, after milling, the macronutrients enclosed in the intact cells are released and are easily accessible to digestive enz...

Probiotics have received increased attention due to their nutritional and health-promoting benefits. However, their viability is often impeded during food processing as well as during their gastrointestinal transit before reaching the colon. In this study, probiotic strains Lactobacillus rhamnosus MF00960, Pediococcus pentosaceus MF000967, and Lact...

Significant innovations have occurred over the past 50 years in the malting and brewing industries, focused on optimization of the beer mashing, boiling and fermentation processes. One of the challenges faced in beer brewing has been in the malting process to obtain the desired malt and wort quality to produce high-quality beer products. The hydrol...

Nature has developed starch granules varying in size from less than 1 μm to more than 100 μm. The granule size is an important factor affecting the functional properties and the applicability of starch for food and non-food applications. Within the same botanical species, the range of starch granule size can be up to sevenfold. This review critical...

Starch exists naturally as insoluble semi-crystalline granules assembled by amylose and amylopectin. Acknowledging the pioneers, we have reviewed the major accomplishments in the area of starch structure from the early 18th century and further established the relation of starch structure to nutritional functionality. Although a huge array of work i...

Wheat is a potential source of oxidized starch, but there is no systematic study reporting the effects of oxidation conditions on the structural changes and subsequent physical properties. We report the properties of oxidized wheat starch granules treated with 2, 5, and 10% hydrogen peroxide (at pH 4 and 10) or sodium hypochlorite (at pH 4, 7, and...

Background The interest in plant-based protein sources has risen in the last few decades due to their benefits to human health, the environment and sustainable farming. Lupins are a protein-rich legume crop, popular as fodder but limited for human consumption due to the presence of alkaloids. The sweet lupin varieties (free of/reduced alkaloid) dev...

High amylose wheat flour (HAWF) is a relatively new food ingredient, with potential for enhanced nutritional functionality of slower digestion and greater resistant starch levels compared to wild-type wheat flour (WTWF) products. This study focusses on the role of amylose content in the baking process and eating qualities of bread, made using an in...

The human gut microbiota are mostly regulated and stabilized by available macro-nutrients (carbohydrates, proteins and lipids) excursed to colonic fermentation. Resistant starch (RS) has been shown to be metabolized to specific short-chain fatty acids (SCFAs) in the colon associated with proven health benefits. However, the in vitro fecal fermentat...

Temperature-induced structural variations of retrograded starch gel during long-term storage were investigated in a real food system (wet starch noodles). Fresh starch noodles presented a B-type XRD pattern containing 8.82% crystallinity and 16.04% double helices. In the first 2 weeks, double helices of starch chain formed long-range ordered struct...

Processing induced structural changes of whole foods for the regulation of the colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from pinto beans were isolated as a whole pulse food model and subjected to a series of processing temperatures to modulate the st...

Along with the brief outline of the definition evolution of dietary fibers, this chapter focuses on how the physical and chemical structures of fibers are related to the health effects. The role of fiber in the human digestive tract including oral, gastric, small intestinal, and large intestinal phases is also discussed. Our further emphasis is on...

Intact legume cotyledon cell walls (CW) hinder the access of digestive enzymes and maintain the physical integrity of cellular structures under in vitro and in vivo conditions, resulting in the transport of cellular structures and their contents from food legumes to the large intestine. The subsequent colonic fermentation of intact legume cells and...

The concept of “enterotype” has been proposed to differentiate the gut microbiota between individual humans, and different dominant bacteria utilize fiber substrates with different fermentation properties and microbial changes. In this study, we made propionylated high-amylose maize starch and investigated both in vitro fecal fermentation propertie...

The in vitro fecal fermentation characteristics and microbiota responses to A- and B-type polymorphic starches as model (whole) foods enriched with resistant starch was investigated. Marked difference in fermentation rate as well as microbial genera was observed during fermentation, the degradation pattern as well as structural evolution during fer...

Dietary fibre (DF) is increasingly being recognised as playing an important role in positive metabolic and health effects. Cell walls in the endosperm and cotyledon of plant foods are an important source of DF, and its behaviour in the digestive tract underlies the health-beneficial mechanisms. In the small intestine, the extent to which cell walls...

White-salted noodles are prepared, stored and consumed in various ways. However, relationships among cooking and storage conditions on nutritional functionality are not fully understood. The manuscript elucidates the mechanism of formation of resistant starch (RS) leading to slower digestion rate of variously cooked (boiled, steamed, stir-fried, fr...

Hemicelluloses, a family of heterogeneous polysaccharides with complex molecular structures, constitute a fundamental component of lignocellulosic biomass. However, the contribution of each hemicellulose type to the mechanical properties of secondary plant cell walls remains elusive. Here we homogeneously incorporate different combinations of extra...

Dietary fat in food-matrix plays an important role in improving the bioaccessibility of lipophilic micronutrients. Conventionally, surfactants and amphiphilic biopolymers have been used to stabilize the lipid and aqueous phase. Recently, the particle-stabilized emulsions, or referred to as ‘Pickering emulsions’, are studied extensively due to their...

Wheat flour, consisting of a complex matrix of starch and protein, is used as a representative model of whole food here to investigate the binary interaction in relation to amylose level and hydrothermal treatment in noodles as a food exemplar. Noodle made of high-amylose wheat (HAW) flour showed an eight-fold higher resistant starch content, compa...

Apart from starch, non-starch polysaccharides (fibers) play important roles in the functionality of gluten. The effect is more pronounced while preparing fiber-enriched cereal products, where additional fibers add further complexity to the starch-protein network. However, how dietary fibers, even of a small amount, could largely affect the properti...

High-amylose wheat starch (HAWS) and flour (HAWF) have the potential to deliver food products with enhanced nutritional functionality, but structure/function relationships are not well understood. We report the structural bases for differences in water absorption and pasting properties for HAWS and HAWF (amylose contents 71-84%) compared with wild-...

Starch digestion in pulse cellular matrices is primarily determined by the hindrance of cell walls limiting enzyme diffusion as well as the retention of starch granular structure. However, the effect of hydrothermal treatment on structure and digestion properties of entrapped pulse starches is not fully elucidated. In present study, we reported the...

The dense packing and encapsulation of starch by protein are considered important for the digestion of noodles and the textural attributes. This study aims to elucidate the effect of gluten on the noodle texture and starch digestion rates. The structure of cooked noodles was characterized using a scanning electron microscope and Fourier-transform i...

Granular protein is an important structural feature in determining starch digestibility. High-amylose wheat starch (HAWS) with >80% amylose content contains more granular protein than wild-type starch. As analyzed by mass spectrometry-based proteomics, granular-bound starch synthase (GBSS) is the major granular protein in isolated starch materials....

Noodles are widely consumed in China, which can be cooked in different ways. The effects of different cooking methods (boiling, steaming, microwave heating, stir-frying and frying) on the resistance starch (RS) content and digestive properties (digestion rate, digestibility and estimated glycemic index (eGI) value) of noodles were investigated. The...

For regular starches, gelatinisation occurs over a relatively narrow temperature range in excess water; however, high-amylose starches typically gelatinise over an extended temperature range by a process that is less understood. The present study compared granule organisation of high-amylose starches from wheat (HAWS) and maize (HAMS), and investig...

Food structure is a key determinant for the release of phenolic compounds during gastric and intestinal digestion. We evaluated the bioaccessibility of polyphenols from apple tissue during gastric digestion in vitro from bio-mechanical perspectives including the effects of gastric juice and mucin on apple tissue matrix under simulated stomach peris...

Intact pinto bean cotyledon cells were isolated and hydrothermally treated at three different moisture contents (15%, 25% and 35%) at 100 °C for 8 h to investigate the effect of cell wall encapsulation on starch molecular re-arrangement during heat-moisture treatment (HMT). Compared to the intact cells, HMT had a more pronounced effect on isolated...

Background Starch is the major stored carbohydrate in grains and legumes. Apart from nutritional functionality, starch has multiple industrial applications. Starch is synthesised in plant cells along with proteins, lipids, and polyphenols. These macromolecules interact both in planta as well as during downstream processing, e.g., extraction of star...

Starch branching enzymes (SBEs) play a major role in determining starch molecular structure in cereal endosperm. This study investigates how SBEIIs contribute to the chain-length distributions (CLDs) of both amylopectin and amylose, obtained by enzymatic debranching of native starch. Wheat starches with low (37%) to high (93%) amylose content were...

Enzyme digestion of starch granules encapsulated within cell walls in pulse depends on both the intactness of cellular structure as well as the retention of the ordered structure of starch during processing. However, the role of cell wall permeability in starch digestion, as affected by processing conditions, has not been fully elucidated. In this...

Two models for the digestion of starch in foods are considered: sequential, where two or more reactions follow one another, and parallel, where they occur simultaneously. Each reaction is assumed to be first-order, and to be characterized by a rate coefficient and a digestible fraction. For parallel kinetics, a new fitting method is developed; meth...

Millets are widely consumed cereal grains in Asia, Africa and some parts of Eastern Europe. Although, underutilized in the western world, they are rich sources of major nutrients including carbohydrates, proteins, lipids, fibres, minerals, and vitamins. Unlike wheat, barley or rye, millet is gluten-free and can be used to make nutritious and health...

Starch that escapes intestinal digestion (resistant starch, RS) is non-glycaemic and considered as dietary fibre. In planta increase of amylose content is a promising approach to make starch resistant to enzyme digestion. Compared to maize, little is known on the effect of amylose content at different length scales of high-amylose wheat (HAW) starc...

Oral processing of solid foods is an extremely dynamic and complicated activity that involves multiple processes in tandem such as comminution, mixing, dilution, hydration and enzymatic breakdown that gradually transform the food from a morsel or a bite to a bolus that is ready for swallowing. It is hypothesised that just after “first bite” and ini...

An increase in the hardness during storage of Ready-to-eat (RTE)-cooked noodles is considered as a major quality problem. This study showed the noodle hardness can be manipulated by tuning the starch initial crystallinity with an explicit mechanism. Noodles were prepared from pre-gelatinized/native wheat starch and gluten with varied crystallinity...

Understanding the structural factors related to the starch digestibility of cooked milled rice grains is important in mitigating the impact of diet-related diseases. In this study, changes in starch structure of rice during in vitro digestion and retrogradation is reported for 8 varieties of indica milled rice with apparent amylose ranges from 3 to...

Although high‐amylose starches are not a recent innovation, their popularity in recent years has been increasing due to their unique functional properties and enhanced nutritional values in food applications. While high‐amylose maize, barley, and potato are commercially available, high‐amylose variants of other main crops such as wheat and rice hav...

Rice is one of the staple foods which serves as the major source of carbohydrate in the human diet. A typical milled rice grain is mainly composed of starch of up to 80–90%, with an average of 6–8% proteins and some trace amounts of dietary fiber. Although cooked white rice can elicit variable glycemic response, a portion of rice starch may evade d...

Macronutrients in whole plant foods are enclosed inside cells. The metabolic response from these entrapped nutrients may depend on cell-wall porosity, by controlling the passage of digestive enzymes. As non-interacting size mimics of digestive enzymes, we investigated the diffusion of fluorescently-labelled probes across the walls of isolated plant...

The crosslinking of arabinoxylan chains with ferulic acid dimers in wheat endosperm cell walls is hypothesised to limit the swelling and solubilisation of cell wall polysaccharides. In this study, we report the changes in the rheological and chemical properties of cell walls isolated from wheat flour and purified endosperm after treatments intended...

Although many studies have investigated the enzyme susceptibility of bean starches, the factors that reduce the lower hydrolysis of bean starch are not well understood. In the present study, we isolated starches from eight commercial bean varieties and established a causal relationship between micro and macro-structure with α-amylase susceptibility...

The properties of bio-films prepared from sorghum starch using three different modification techniques (hydrothermal treatment (HTT), acid-alcohol treatment (AA) and acetylation (A)) were studied. The physical properties of modified starches were significantly different from unmodified starches. More specifically, acetylated starch had significantl...

The cell walls of cereal endosperms are a major source of fibre in many diets and of importance in seed structure and germination. Cell walls were isolated from both pure wheat endosperm and milled flour. ¹³C CP/MAS NMR in conjunction with methylation analysis before and after acid hydrolysis showed that, in addition to arabinoxylan (AX) and (1, 3;...

High-moisture rice snacks, such as steamed rice cakes, develop firmness on storage which decreases shelf life significantly. By analogy with lower moisture bread systems, this staling was hypothesised to be due to a combination of starch retrogradation and moisture re-distribution. Therefore, food additives which are commonly used to retard starch...

The microstructure of foods and their response to both deformation and hydration is anticipated to be a key driver in texture and taste perception during comminution and oral processing. Here we characterise the microstructure of potato chips (crisps) using a broad range of microscopy techniques and labelling methods to capture potato cell structur...

Limiting the rate and extent of starch digestion is a major target for increasing the nutritional value of cereal-based foods. One mechanism that could be exploited is the ability of intact cell walls to protect intracellular starches from enzyme hydrolysis, but the extent to which this mechanism is valid for cereal endosperm cells is not well unde...

Sheds some light as to whys and hows of improving the nutritional functionality of wheat flour.

This presentation is about a new insight into the composition and properties of wheat endosperm cell walls.

The ability of phenolic compounds to bind to dietary polysaccharides such as starch and plant cell wall components impacts their nutritional value. Here, we report interactions between potato cells and three different phenolic compounds (+)-catechin, phloridzin and vanillic acid. The binding interactions of the phenolic compounds with intact potato...

This presentation explains how the starchy endosperm cell walls differ from the cell walls from milled flour.

The glycemic potency of rice depends upon the rate and extent of starch hydrolysis by pancreatic amylase and intestinal alpha-glucosidases. However, complexation of starch molecules with lipids is known to reduce the enzymic hydrolysis. In this study, we elucidated the varietal effect of rice starches on the formation of amylose-lipid complex, afte...

An intervention study was conducted to determine the in vivo digestibility of a commercial Type 4 resistant starch, namely, cross-linked phosphorylated (0.4% P) wheat starch (CLP wheat starch). Commercial unmodified (native) wheat starch was the negative control. Eleven ileostomy subjects participated in a randomized, double-blinded, cross-over des...

Although the processing and eating qualities of noodles are largely related to the quality and quantity of wheat protein (gluten), the importance of starch, a major ingredient of wheat flour, is often overlooked. Recent developments on the multilevel structural model of starch have brought new insights into the role of starch for better processing...

Retention of intact plant cells to the end of the small intestine leads to transport of entrapped macronutrients such as starch and protein for colonic microbial fermentation, and is a promising mechanism to increase the content of resistant starch in diets. However, the effect of gastro-intestinal bio-mechanical processing on the intactness of pla...

The changes in physical, rheological and enzyme-digestive behaviours of cooked white and brown rice, with similar amylose content, were investigated using a dynamic in vitro rat stomach (DIVRS) model and a static soaking method. The brown rice had a higher resistance on disintegration and lower gastric emptying rate with 53% of the brown rice parti...

The present study modified maize and potato granular starches by partial debranching treatment below the gelatinization temperature, and investigated their structural and physicochemical properties. Pullulanase was much effective (more than three times) on hydrolyzing potato starch compared to maize starch as measured from total carbohydrate values...

We report the isolation of a pure form of cell walls from wheat endosperm ‘popped’ out from the whole, enzyme deactivated and soaked grain, and compare them with cell walls isolated from milled flours of extraction rates from 45% to 75%, at physiological (37 °C) and elevated (70 °C) temperatures. Cell walls isolated from flours all contained non-en...

In this study we investigated the in vitro digestive behaviors of starch-based diets enriched with soluble fiber (pectin) and fruit powder (mango) varying with dry matter contents using a dynamic rat stomach and duodenum model. The changes in pH with respect to digestion time, gastric emptying, starch and protein hydrolysis as well as rheological a...

This study investigated the survival of probiotic Lactobacillus plantarum 299v microencapsulated in native maize starch or partially hydrolyzed maize starches after acid, bile and heat treatments. Scanning electron microscopy and confocal scanning laser microscopy confirmed that naturally present cavities and channels in native maize starch were en...

The tribological properties of suspensions of cooked swollen starch granules are characterised for systems based on maize starch and potato starch. These systems are known as granule ‘ghosts’ due to the release (and removal) of polymer from their structure during cooking. Maize starch ghosts are less swollen than potato starch ghosts, resulting in...

The rate of enzymic digestion of the three major macronutrients (protein, triglyceride and starch) in the human diet has a controlling influence on physiological and hormonal responses underpinning many of the risk factors for major non-communicable diseases. Previously, the interactions among macronutrients and the inter-dependence of individual m...

Hydrated polysaccharides and their assemblies are known to modulate gastric emptying rate due to their capacity to change the structural and rheological properties of gastric contents (digesta). In the present study, we investigated the rheological and microstructural properties of gastric digesta from pigs fed with diets incorporating mango powder...

Increasing the level of starch that is not digested by the end of the small intestine and therefore enters the colon (‘resistant starch’) is a major opportunity for improving the nutritional profile of foods. One mechanism that has been shown to be successful is entrapment of starch within an intact plant tissue structure. However, the level of tis...

Waxy, normal and high-amylose maize starches were extruded with water as sole plasticizer to achieve low-order starch matrices. Of the three starches, we found that only high-amylose extrudate showed lower digestion rate/extent than starches cooked in excess water. The ordered structure of high-amylose starches in cooked and extruded forms was simi...

Gluten free pasta was made from raw banana flour in combination with vegetable gums and protein for comparison to pasta similarly made from wheat flour. After cooking, it was found that the banana flour pasta was less susceptible to alpha-amylase digestion compared to conventional wheat flour pasta. Release of glucose by alpha-amylase digestion fol...

We report on inhibition of α-amylase activity by cellulose based on in vitro experiments. The presence of cellulose in the hydrolysing medium reduced the initial velocity of starch hydrolysis in a concentration dependent manner. α-Amylase adsorption to cellulose was reversible, attaining equilibrium within 30min of incubation, and showed a higher a...