Bruce R. Hamaker's research while affiliated with Purdue University and other places

Publications (422)

Article
The use of plant-based proteins to replace animal proteins is gaining interest from consumers and food processors, with plant proteins now having become a major ingredient commodity. Even though the commercial plant proteins used today (e.g., soybean and pea) are good texturizing proteins as evidenced by their widespread use in plant-based analogue...
Article
Incorporation of soluble dietary fiber to cereal extrudates is a practical approach to improve its nutrition values, but it can be technically challenging as a reduction in extrudate quality commonly occurs at a high incorporation level. In the present study, we incorporated soluble corn arabinoxylan (CAX) into cornmeal at a high level (25% w/w) an...
Preprint
Parkinson's disease (PD) is a movement disorder characterized by neuroinflammation, α-synuclein pathology, and neurodegeneration. Most cases of PD are non-hereditary, suggesting a strong role for environmental factors, and it has been speculated that disease may originate in peripheral tissues such as the gastrointestinal (GI) tract before affectin...
Article
Full-text available
Purpose: To test the hypothesis that oral ingestion of slowly digestible carbohydrates (SDCs) that reach the ileum triggers the ileal brake as indicated by delayed gastric emptying, reduced glycemic response, and decreased subjective appetite. Methods: The study was a five-arm, randomized, double-blind, crossover trial with a 1-week washout period...
Article
The effect of resistant starch type 5 (amylose‐lipid complex, ALC) from maize starch and maize meal on short‐chain fatty acids (SCFAs)production by in‐vitro human faecal fermentation was determined. The maize starch and maize meal were modified using heat‐moisture treatment (HMT), stearic acid (SA), combination treatment (SA+HMT), and a control. Th...
Article
The Andean geography induces favorable conditions for the growth of food plants of high nutritional and functional value. Among these plants are the Andean grains, which are recognized worldwide for their nutritional attributes. The objective of this article is to show the nutritional and functional properties, as well as industrial potential, of A...
Article
A self-assembled soluble nanoparticle, composed of common food biopolymers (carbohydrate, protein) and lipid, was previously reported by our laboratory. Although carrying capacity of valuable small molecules was demonstrated, physical functional properties are also important. Given the stabilization or destabilization characteristics of Hofmeister...
Article
Full-text available
Processed foods often include food additives such as xanthan gum, a complex polysaccharide with unique rheological properties, that has established widespread use as a stabilizer and thickening agent. Xanthan gum’s chemical structure is distinct from those of host and dietary polysaccharides that are more commonly expected to transit the gastrointe...
Article
Traditional West African pearl millet couscous products are popular; however, their preparation is laborious, time‐consuming, and energy‐demanding, involving agglomeration, steaming, drying, and sieving steps. In the present study, a process was developed to produce millet couscous using a high pressure, high temperature, low‐cost single‐screw extr...
Article
Corn arabinoxylan (CAX), a cell wall-derived dietary fiber, was extracted with alkali, partially purified, and treated with hydrolytic enzymes in order to investigate the relationship of fine structure and fermentability by the human gut microbiota. Glycosyl composition and linkage analysis of CAX and two hydrolysates, coupled with molecular size a...
Article
This review systematically documents the major different strategies of generating high-amylose (HAS) starch mutants aiming at providing high resistant starch, by engineering the starch biosynthesis metabolic pathways. We identify three main strategies based on a new representation of the starch structure: ‘the building block backbone model’: i) sup...
Article
Plant cell wall-derived dietary fiber (PCWDF) is not only complex in chemical compositions and physical structures, but also co-exists with many other intracellular food components in a form of plant tissue. PCWDF can reduce the bioaccessibility of intracellular food components including lipids, starch and protein through an encapsulation mechanism...
Article
Background: Epidemiological and some clinical studies support the view that whole grain foods have lower glycemic response compared to refined grain foods. However, from the perspective of food material properties, it is not clear why whole grain cereals containing mostly insoluble and non-viscous dietary fibers (e.g., wheat) would reduce postprand...
Article
Isomaltodextrin (IMD) is a novel highly branched α‐glucan ingredient that has potential applications in foods as a promising source of dietary fibre. In this study, we assessed the incorporation of IMD in baked products and its effect on dough rheology and physico‐textural characteristics of wheat breads. IMD was added to wheat flour to reach the U...
Article
Full-text available
In 2008, the Choices International Foundation developed its logo criteria, identifying best-in-class food products. More advanced, global and graded nutrient profiling systems (NPSs) are needed to substantiate different national nutrition policies. The objective of this work was to extend Choices NPS to identify five levels of the healthiness of fo...
Article
The impact of the internal part of aewx amylopectin on the gel network and digestibility during retrogradation was investigated using wx amylopectin as a reference. After β-amylolysis for 60 min (aewx-60), greater shifts in both λmax value and absorbance of iodine binding profiles were observed, accompanied by an increment of short chains (DP 3-5)...
Article
Background: Changes in preparation, preference, and consumption of traditional staple foods between rural and urban areas in sub-Saharan Africa may be associated with the nutrition transition. Objective: Millet porridge thickness and postprandial hunger were investigated in Mali with the aim of understanding consumer preference and satiety propert...
Article
Full-text available
Fruit peels are considered non-conventional sources of dietary fiber (DF). Extrusion can modify DF solubility, thus potentially improving its physiological and technological functionalities. Unprocessed orange, mango and prickly pear peels (OU, MU, PU), and extruded peels (OE, ME, PE) were submitted to fecal in vitro fermentations. DF solubility, g...
Article
Insoluble dietary fibers are typically known to be poorly fermented in the large intestine. However, their value may be high as evidence shows that important butyrogenic bacteria preferentially utilize insoluble substrates to support their energy needs. The objective of this study was to increase fermentability of an insoluble bran fiber (pearl mil...
Article
While increasing cases related to gluten intolerance have encouraged scientists to develop healthier and better-quality gluten-free products, a more ideal viscoelastic behavior is still needed. In this study, we systematically investigated a dough system composed of corn zein, starch, and additional protein (5% of total protein, termed "co-protein"...
Article
Complete starch extraction has been a problem in the corn wet-milling, and here enzymes affecting different structures were used to provide a thorough understanding of the contribution of those structures to starch and protein retention for a way to achieve higher extraction rates. The combination of Frontia Fiberwash® (mix of cellulases and xylana...
Article
Pearl millet flour, particularly wholegrain flour, is highly susceptible to development of rancid aromas and flavors during storage. Grain decortication and extrusion cooking using a friction-heated single-screw extruder were investigated as potential flour stabilization processes. Raw and extruded wholegrain and decorticated grain pearl millet flo...
Article
Dysregulated glucose metabolism is associated with many chronic diseases such as obesity and type 2 diabetes mellitus (T2DM), and strategies to restore and maintain glucose homeostasis are essential to health. The incretin hormone of glucagon-like peptide-1 (GLP-1) is known to play a critical role in regulating glucose homeostasis and dietary nutri...
Article
Nowadays, carbohydrate-based foods have a negative consumer connotation and low carb diets have become a popular way to lose weight. Here, we show how digestible starch and flavonoids can be used as a dietary approach to manage food intake and weight gain through elevation of glucagon-like peptide-1 (GLP-1) secretion for gut-brain axis communicatio...
Article
In the present study, 14 structurally unique flavonoids were screened to systematically investigate structural requirements for selectively inhibiting human α-amylase versus α-glucosidase to obtain a slow but complete starch digestion for health benefit. The selective inhibition property of three flavonoids chosen against the two classes of starch...
Article
Complete starch extraction has long been an issue in the wet-milling industry, and here structures in the fine and coarse fiber fractions that retain starch were identified and quantified for potential treatments to increase starch and protein extraction rates. Six main structures were identified in the fiber fraction and three of them were directl...
Article
The effect of soy protein isolate (SPI) and dietary fibers [maize bran (MB), resistant maltodextrin (RMD)] on cooked extruded rice quality-related parameters and relating rheology to the human gastric emptying measurement of Lag phase were investigated. DSC onset temperature (To) and peak temperature (Tp) of extruded rice substituted with 20 % SPI...
Article
Full-text available
In the face of interindividual variability and complexity of gut microbial communities, prediction of outcomes from a given fiber utilized by many microbes would require a sophisticated comprehension of all competitive interactions that occur in the gut. Results presented here suggest that high-specificity fibers potentially circumvent the competit...
Article
Full-text available
Background Physiologic aging has been associated with gut dysbiosis. Although short exercise interventions have been linked to beneficial changes in gut microbiota in younger adults, limited data are available from older populations. We hypothesized that exercise would produce beneficial shifts in microbiota and short-chain fatty acid (SCFA) levels...
Preprint
Full-text available
The diets of industrialized countries reflect the increasing use of processed foods, often with the introduction of novel food additives. Xanthan gum is a complex polysaccharide with unique rheological properties that have established its use as a widespread stabilizer and thickening agent1. However, little is known about its direct interaction wit...
Preprint
Full-text available
The diets of industrialized countries reflect the increasing use of processed foods, often with the introduction of novel food additives. Xanthan gum is a complex polysaccharide with unique rheological properties that have established its use as a widespread stabilizer and thickening agent. However, little is known about its direct interaction with...
Article
In this study, a glucanotransferase from prokaryotic Azotobacter chroococcum NCIMB 8003 was recombinantly expressed and its biochemical characteristics and bioconversion ability for starch were investigated. The purified enzyme has the optimum activity at 55 °C and pH 6.5-7.0, as well as a melting temperature of 62 °C. The double-charged ion Ca2+ s...
Chapter
Whole grains or whole grain foods contain “all the essential parts and naturally-occurring nutrients of the entire grain seed in their original proportions” and its carbohydrates include endosperm starch and non-starch polysaccharides, and minor amounts of inulin and simple sugars. A good understanding of the mechanism and role carbohydrates play i...
Article
Food-to-food fortification (FtFF) with moringa leaf (iron source) and/or baobab fruit (citric acid and ascorbic acid source) (each 13–15 g/100 g porridge dry basis (db)) was studied to improve iron and zinc nutritive quality in African-type wholegrain maize-based porridges using in vitro dialysability assay. Moringa FtFF decreased percentage and to...
Article
Small-scale affordable extruders create new opportunities for small enterprise food processors to manufacture nutritionally enhanced products. Still, consumer interest in these products needs to be assessed first. Affective tests with 296 consumers in Dakar, Senegal, evaluated five pearl millet flours: (a) conventional, compared to four instant-por...
Article
The structure-function relationships of plant-based proteins that give rise to desirable texture attributes in order to mimic meat products are generally unknown. In particular, it is not clear how to engineer viscoelasticity to impart cohesiveness and proper mouthfeel; however, it is known that intermolecular β-sheet structures have the potential...
Article
Three different storage temperatures including room temperature (RT), 4 °C and −20 °C were investigated in this study, with respects to their effects on the retrogradation property and in vitro digestibility of gelatinized sago starch. Storage at −20 °C resulted in the highest amount of both intra- and intermolecular double helices and a fracture-l...
Article
Impairments in physical function and increased systemic levels of inflammation have been observed in middle-aged and older persons with HIV (PWH). We previously demonstrated that in older persons, associations between gut microbiota and inflammation differed by HIV serostatus. To determine whether relationships between the gut microbiome and physic...
Article
Full-text available
As the prevalence of obesity and diabetes has continued to increase rapidly in recent years, dietary approaches to regulating glucose homeostasis have gained more attention. Starch is the major source of glucose in the human diet and can have diverse effects, depending on its rate and extent of digestion in the small intestine, on postprandial glyc...
Article
Most insoluble dietary fibers are known to be relatively poorly fermented by the human gut microbiota. Here, the potential of microwave (MW) treatment to enhance the susceptibility of insoluble fruit polysaccharides to fermentation by the human gut microbiota was evaluated. Insoluble fruits dietary fibers before (xylan A, xylan T, and arabinan) and...
Article
Heavy metals (HMs) in crops and processed foods are a concern and pose a potential serious health hazard. This study investigated possible presence of HMs in grains and processed products in the Region of Arequipa in Peru. Concentrations of Cd, As, Sn, Pb, and Hg were determined for commonly consumed grains in 18 districts of the region and process...
Article
Even though starch seems a simple carbohydrate, composed only of glucose connected by two types of linkages, it has an amazing complexity related to its branched structure and extremely large size. Today, there are still unanswered questions that present challenges to the starch research field. Even though advances have been made in correlating sta...
Article
Full-text available
Partial hydrolysis of whey‐based α‐Lactalbumin (α‐La) with Bacillus licheniformis protease (BLP) induces the formation of nanotubular structures in the presence of calcium ions by a self‐assembly process. α‐La nanotubes (α‐LaNTs) exist in the form of regular hollow strands with well‐defined average dimensions. The growth of nanotubes induces the fo...
Article
While gut bacteria have different abilities to utilize dietary fibers, the degree of fiber structural alignment to bacteria species is not well understood. Corn bran arabinoxylan (CAX) was used to investigate how minor polymer fine structural differences at the genotype × environment level influences the human gut microbiota. CAXs were extracted fr...
Article
The potential anti-staling property of starches with slow-retrograding amylopectin was studied in soft wheat bread and cake model systems. Normal rice, waxy rice, and wheat starches were processed by drum drying or extrusion, and native starch was used as a comparator. Extrusion processing causing amylopectin fragmentation can reduce intermolecular...
Article
In a previous trial in Mali, we showed that traditional pearl millet couscous and thick porridge delayed gastric emptying (about 5 h half-emptying times) in a normal-weight population compared with non-traditional carbohydrate-based foods (pasta, potatoes, white rice; about 3 h half-emptying times), and in a gastric simulator we showed millet cousc...
Article
Assessing rheological properties of biofortified maize through post-harvest storage is critical for its successful translation to consumer foods. Changes in flour rheology were assessed following post-harvest storage in Purdue Improved Crop Storage (PICS) of a white and two biofortified orange maize genotypes (OPVI and OPVII). Whole grains were sto...
Article
Isomaltodextrin (IMD) is a novel highly branched α‐glucan with emerging applications in foods due to its nutritional functionalities. In this study, the impact of IMD on the viscoelasticity and microstructure of starch gels and starch retrogradation were investigated. IMD solutions displayed typical Newtonian behavior. Their viscosities had a posit...
Article
During processing of refined cereal grain foods, cell wall fibers present in whole grains are diminished and are often replaced with dissimilar soluble fibers. Contrary to a view that soluble fibers are generally preferable for health and that the removed insoluble bran cell wall fibers of whole grains provide bulk for laxation, a body of evidence...
Article
Emerging evidence suggests intestinal microbiota as a central contributing factor to the pathogenesis of Relapsing-Remitting-Multiple-Sclerosis (RRMS). This novel RRMS study evaluated the impact of fecal-microbiota-transplantation (FMT) on a broad array of physiological/clinical outcomes using deep metagenome sequencing of fecal microbiome. FMT int...
Article
Full-text available
Background: Variability in the health effects of dietary fiber might arise from inter-individual differences in the gut microbiota’s ability to ferment these substrates into beneficial metabolites. Our understanding of what drives this individuality is vastly incomplete and will require an ecological perspective as microbiomes function as complex i...
Article
The effect of formulating orange juice with dietary fiber (DF) on in vitro bioaccessibility of flavonoids and their ability to inhibit glucose transport in Caco-2 cells were investigated on Valencia orange fruit (OF), orange juice (OJ) and OJ formulated with 1% and 2.8% DF. DF were either orange pomace (P) or commercial pulverized citrus pulp fiber...
Article
Amide I and Amide III vibrational modes are frequently used to study protein secondary structure with Fourier transform infrared (FT-IR) spectroscopy. However, for protein mixtures, neither the sole Amide I nor Amide III region provides sufficient information for structural quantitation because of overlapping peaks, especially in the Amide I region...
Article
A structure-digestion model is proposed to explain the formation of α-amylase-slowly digestible structures during amylopectin retrogradation. Maize and potato (normal and waxy) and banana starch (normal and purified amylopectin through alcohol precipitation), were analyzed for amylose ratio and size (HPSEC) and amylopectin unit- and internal-chain...
Article
Objectives Polyphenol intake has been associated with improved health outcomes, but the relation between polyphenol intake, gastrointestinal health, and systemic health outcomes is not fully known. Many polyphenols become bioavailable once transformed into metabolites by the gut microbial community. Thus, it is reasonable to assume that the intimat...
Article
Full-text available
Differences in the chemical and physical properties of dietary fibers are increasingly known to exert effects on their fermentation by gut microbiota. Here, we demonstrate that maize bran particle size fractions show metabolic output and microbial community differences similar to those we previously observed for wheat brans. As for wheat brans, mai...
Article
Full-text available
Previously, we have identified and characterized 4,6-α-glucanotransferase enzymes of Glycosyl Hydrolase (GH) family 70 (GH70) that cleave (α1→4)-linkages in amylose and introduce (α1→6)-linkages in linear chains. The 4,6-α-glucanotransferase of Lactobacillus reuteri 121, for instance, converts amylose into an Isomalto/Malto-Polysaccharide (IMMP) wi...
Article
Full-text available
Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these...
Article
Objectives Maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) are mucosal α-glucosidases required for the digestion of starch to glucoseWe hypothesized thata dietary approach to reduce Mgam and Si activities can reduce glucose generation and absorption, and improve glucose control. Methods Rice starch was entrapped in alginate microspheres to...
Article
Supplementation with resistant starches of different structures led to divergent shifts in key bacterial taxa abundance and distinct butyrate or propionate outcomes. A recent randomized controlled trial (RCT) reported by Deehan et al. showed similar responses within treatment groups and dose-response plateauing at 35 g/d. These results support a pr...
Article
Resistant starch type 3 (RS3) benefits colon health, but the molecular structural reasons for this effect are unclear. Five rice starches with varied amylose content (19.1%-40.6%) were used to investigate their effect on gut microbiota. Size-exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis were used to characterize who...
Article
Viscoelasticity of corn zein is associated with the formation of β-sheet secondary structures; however, studies of the fundamentals of this conformational change are limited due to zein insolubility and poor analytical resolution. Here, changes in soluble zein conformation were evaluated as the protein self-assembles in increasingly hydrophilic sol...
Article
Shear forces are important during food processing, food consumption, and food digestion, and often are estimated to evaluate their effects on product quality. However, few studies have been done on shear-induced structure changes of starch/hydrocolloid systems. Our previous work showed that gelatinized waxy potato starch forms a strong viscoelastic...
Article
Blends of cereals and nutrient dense plant materials are increasingly being explored as a strategy for food-to-food fortification in areas of Sub-Saharan Africa, where processing is often applied to enhance product attributes, shelf life and safety. However, little is known regarding the potential impact of these strategies on micronutrient retenti...
Article
Full-text available
Background Maize is the major food staple in East and Southern Africa, where food-processing industries are emerging fast. New low-cost extrusion cookers allow small enterprises to enter the market for processed cereals, including instant, fortified, and flavored products. Objective Assess consumers’ interest and preferences for the new products....
Article
Waxy potato amylopectin has longer internal and external linear chains than rice or corn amylopectin, that are capable of retrograding to a higher degree, but its molecular recrystallization is impeded by unprotonated phosphate groups. Here, we studied whether retrogradation and gel properties of waxy potato starch can be enhanced by lowering pH. G...
Article
We sought to determine whether design of carbohydrate-based microspheres to have different digestion rates, while retaining the same material properties, could modulate gastric emptying through the ileal brake. Microspheres made to have three slow digestion rates and a rapidly digested starch analogue (maltodextrin) were administrated to rats by ga...
Article
Full-text available
Dietary fibers can be utilized to shape the human gut microbiota. However, the outcomes from most dietary fibers currently used as prebiotics are a result of competition between microbes with overlapping abilities to utilize these fibers. Thus, divergent fiber responses are observed across individuals harboring distinct microbial communities. Here,...
Article
Consumption of traditional West African pearl millet (Pennisetum glaucum) couscous delayed gastric emptying in our recent human study compared to other starch-based foods (white rice, boiled potatoes, pasta). The objective of this study was to determine whether physical properties of pearl millet couscous affect particle breakdown and starch hydrol...
Article
Full-text available
Emerging evidence suggests intestinal microbiota as a central contributing factor to the pathogenesis of Relapsing-Remitting-Multiple-Sclerosis (RRMS). This novel RRMS study evaluated the impact of fecal-microbiota-transplantation (FMT) on a broad array of physiological/clinical outcomes using deep metagenome sequencing of fecal microbiome. FMT int...
Article
Efficient nutrient acquisition in the human gut is essential for microbial persistence. Although polysaccharides have been well-studied nutrients for the gut microbiome, other resources such as nucleic acids and nucleosides are less studied. We describe several ribose-utilization systems (RUSs) that are broadly represented in Bacteroidetes and appe...
Article
We previously reported that waxy potato and corn starch amylopectin pastes undergo a shear-thickening behavior that occurs at a low shear rate range of 5 to 25 s−1, and that the effect did not occur for waxy rice starch. Here, we show that the same gelatinized potato amylopectin subjected to a prolonged shear rate of 20 s−1 for 24 h at 5 °C forms a...