Browsing by Author "Fernandez-Fraguas, Cristina"

Now showing 1 - 8 of 8
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    Cellulose-based amorphous solid dispersions enhance rifapentine delivery characteristics and dissolution kinetics in vitro
    Winslow, Christopher Jonathan (Virginia Tech, 2017-07-14)
    The efficacy of rifapentine, an oral antibiotic used in the treatment of tuberculosis, is reduced due to its degradation at gastric pH and low solubility at intestinal pH. We aimed to improve delivery properties in vitro by incorporating rifapentine into pH-responsive amorphous solid dispersions with cellulose derivatives including: hydroxypropylmethylcellulose acetate succinate (HPMCAS), cellulose acetate suberate (CASub), and 5-carboxypentyl hydroxypropyl cellulose (CHC). Most amorphous solid dispersions reduced rifapentine release at gastric pH, with the best performing polymer CASub showing >31-fold decrease in area under the curve compared to rifapentine alone. Lower solubility at gastric conditions was accompanied by a reduction in the acidic degradation product 3-formylrifamycin, as compared to rifapentine alone. Certain formulations also showed enhanced apparent solubility and stabilization of supersaturated solutions at intestinal pH, with the best performing polymer HPMCAS showing almost a 4-fold increase in total area under the curve compared to rifapentine alone. These in vitro results suggest that delivery of rifapentine via amorphous solid dispersion with cellulose polymers may improve bioavailability in vivo.
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    Characterizing Interfacial and Bulk Interactions Between Cellulose Ethers and Bile Salts: Impact on In Vitro Lipid Digestion
    Zornjak, Jennifer Anne (Virginia Tech, 2019-01-14)
    Elevated levels of lipids and LDL-cholesterol in the blood are significant risk factors associated with developing cardiovascular diseases (CVDs). A potential strategy to combat these risk factors is decreasing lipid absorption by modulating the digestibility of lipids in the human intestinal tract. Since bile salts (BS) play key roles during this process, lipid digestion could be controlled ultimately by limiting the access of BS to the lipid surface. Cellulose ethers (CEs), surface-active dietary fibers and common food additives, might be promising ingredients to control lipid digestion either by creating surface layers around lipid droplets that hinder adsorption of BS, or by sequestering BS in the aqueous phase. However, the precise mechanisms behind these interactions remain unclear. Surface analysis techniques were used to better understand the mechanisms by which CEs with diverse molecular structure and charge (commercial and novel hydroxypropyl-cellulose (HPC)) interact with BS at the solid surface and in the aqueous phase. The potential of CE-stabilized emulsions to influence lipid digestion was also investigated in vitro. Both CEs show potential in modulating lipid digestion; the potential of the commercial HPC to interfere with lipid digestion may be more related to its ability to sequester BS in solution and form mixed HPC-BS complexes that are not easily removed from the surface, whereas the novel HPC seems more effective at creating strong surface layers that resist displacement by BS. These findings can be exploited in developing strategies to design novel food matrices with improved functional properties to optimize lipid digestion and absorption.
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    Consumer responses and willingness-to-pay for hibiscus products: A preliminary study
    Ndiaye, Oumoule; Hedrick, Valisa E.; Neill, Clinton L.; Carneiro, Renata C. V.; Huang, Haibo; Fernandez-Fraguas, Cristina; Guiro, Amadou Tidiane; O'Keefe, Sean F. (Frontiers, 2023-04)
    The rise in diseases like obesity and diabetes is a worldwide challenge. The consumption of functional products such as hibiscus, which has been proven to be high in bioactive compounds and dietary fiber, providing it with anticancer, antiaging, anti-inflammatory and satiety properties, should be promoted. In the U.S., promoting the consumption of hibiscus products can be a good approach to increase fiber consumption and to reduce risk of obesity, diabetes, and hypertension. However, information about knowledge of this functional product among consumers is still sparse and increasing consumption requires designing and marketing desired products made from hibiscus. Therefore in this preliminary study, we assessed consumer response to hibiscus products and investigated whether providing information about potential health benefits could impact consumer willingness-to-pay (WTP) for three types of non-alcoholic hibiscus beverages: ready-made tea, bottled juice, and kombucha. Our web-based survey was distributed through Qualtrics(XM) and a convenience sampling method was chosen. Most participants identified themselves as female, 18-34 years old, with a graduate degree. Most participants (81%) had consumed hibiscus products before and 57% had a weekly food budget lower than $60. Overall, tea and juices were the most liked hibiscus beverages, respectively. Although taste and health benefits were ranked as the main reasons to consume hibiscus beverages, additional information about hibiscus health benefits did not significantly affect WTP for these products. Without additional health benefit information, consumer WTP for non-alcoholic hibiscus beverages ranged from $2.9 to $3.60 for kombucha and $4.08-4.97 for Ready-made-tea. This study provides valuable insights that can support future research on hibiscus products and promote the development of novel hibiscus-based foods and beverages that are appealing to the U.S. market.
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    Gut Health Benefits of Natural and Alkali-Processed Cocoa (Theobroma cacao) with and without Inulin
    Essenmacher, Lauren Alexis (Virginia Tech, 2020-06-22)
    Chronic conditions such as obesity, inflammatory bowel disease (IBD), and colitis are associated with gastrointestinal (GI) inflammation and compromised GI barrier integrity. Cocoa may be a potential dietary strategy to mitigate gut-related conditions and been shown to elicit anti-inflammatory, antioxidant, and prebiotic effects. Alkali treatment of cocoa was once thought to reduce its bioactivity, but new evidence suggests it may enhance cocoa's health properties, through the formation of new, potentially bioactive high molecular weight compounds. Inulin, a fructose-containing plant polymer, exerts prebiotic effects and has also been investigated in the mitigation of IBD. This study aims to 1) investigate effects of alkali processing on gut health related bioactivity and phytochemical composition of cocoa and 2) evaluate potential additive benefits of combining cocoa and inulin. Polyphenolic and flavanol compounds in natural cocoa, alkalized cocoa, and inulin powders were characterized using Folin-Ciocalteu (total polyphenols) and 4-dimethylaminocinnamaldehyde (total flavanols) assays, thiolysis , and HILIC UPLC-MS/MS. Treatments of cocoa and inulin were made in 1:2 cocoa:inulin and 1:4 cocoa:inulin mixtures for both natural and alkalized cocoas. Cocoa mixtures, in addition to both cocoa powders and inulin alone, were subjected to an in-vitro digestion to generate material for an in-vitro fecal fermentation. Samples collected from the fermentation at 0, 6, 12, and 24 hours were analyzed via HPLC-MS for microbial metabolites, applied to HT-29 colon cancer cells to assess anti-inflammatory activity, and applied to a florescence assay measuring PLA2 inhibitory activity. The alkalized cocoa powder was found to have a significantly lower concentration of total polyphenols and total flavanols, as well as a lower mDP, suggesting that alkalization may affect larger procyanidins more than smaller flavanol compounds. Inulin enhanced the inhibition of the PLA2 enzyme and enhanced the IL-8 anti-inflammatory properties of cocoa, although the trends were weak. Overall, we did not see any clear, significant effects of alkalization or the addition of inulin to cocoa's colonic metabolite formation or its gut bioactivity in vitro. However, we have demonstrated that colonic fermentation of cocoa may have a negative effect on its bioactivity in vitro. Future research should further explore flavanol DP and bioactivity, fiber's interaction with polyphenols, colonic metabolism of cocoa, and cocoa's gut health effects in vivo.
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    The Influence of Dietary Flavanol Mean Degrees of Polymerization on Sensory Preference Trends and the Metabolic Syndrome
    Griffin, Laura E. (Virginia Tech, 2018-12-05)
    According to the Centers for Disease Control, roughly 9.4% of the US population is diabetic, and at least 35% of the US population has metabolic syndrome. These diseases are associated with increased mortality risk, reduced quality of life, and altered taste perception of foods. With increased occurrence of these metabolic diseases, there is a greater need for research oriented towards using lifestyle modifications to combat illness. A relationship between flavanol consumption, health benefits, and taste perception has been well documented. Dietary flavanols are secondary plant metabolites that exist naturally in a wide array of polymerization states. The mechanisms behind the protective effects of flavanols are not entirely understood, particularly when considering how the mean degrees of polymerization (mDP), or average compound size, impacts the health benefits. Moreover, it is known that flavanol mDP influences the sensory attributes of flavanol-rich foods including bitterness and astringency. It is known that obesity and sensitivity to bitterness both influence perception of certain taste attributes such as sweetness and bitterness. The influence of these bitter and astringent sensations determined by flavanol mDP on consumer preferences for flavanol-rich products remains unknown. These influences on preference pose potential barriers to consumption, resulting in the loss of health benefits. The objectives of the research detailed here were i) to determine the effect of dietary consumption of small to medium-sized flavanols on markers of metabolic syndrome that were brought on by diet-induced obesity, ii) to determine how flavanol mDP influences the consumer perception and liking of flavanol-rich, wine-like products based on differences in consumer phenotype, and iii) to explore the potential to manipulate mDP of wine using traditional winemaking techniques. By way of an in vivo mouse model, it was observed that regardless of mDP, flavanols delivered at low dose, as part of a high-fat diet, reduced adipose-derived inflammatory cytokine production but did not prevent associated weight and fat gain. This suggests that small to medium sized flavanols may, at low dose, delay the onset of the pro-inflammatory state, which could ultimately protect against metabolic derangements associated with obesity and diabetes. Regarding the consumer acceptance of wine-like products made from flavanols of different mDP, and therefore different in bitterness and astringency intensity, it was observed in a consumer panel (n = 102) that when segmenting the panelists by body fat % and BMI classification, increased adiposity was associated with decreased ability to differentiate wine samples made with flavanols of different mDP. Moreover, differences in liking and ability to differentiate bitterness and astringency intensities were not as pronounced when segmenting the panelists based on bitterness sensitivity. This suggests that obesity may impact preference for flavanol-rich foods more so than sensitivity to flavor attributes associated with these products. Finally, in an exploratory effort to manipulate mDP of red and rosé wines using traditional winemaking techniques, no differences in mDP were observed in young wines, but significant differences in flavanol concentration were detected. It is hypothesized that aging of these wines could lead to greater differences in mDP, especially for those that had a high flavanol concentration at baseline. Future work will continue to build off these studies so that flavanol-rich products such as red wine can be optimized for health benefits and consumer acceptability of dietary polyphenols.
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    Integrated processing of brewer's spent grain into value-added protein feedstuff and cellulose adsorbent
    He, Yanhong (Virginia Tech, 2021-09-16)
    Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry, which contains 14–30% protein and 50–70% of fiber. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills, which is a considerable loss of valuable resources, leading to economic loss and environmental problems. Although research has been done on BSG valorization, the studies are limited to producing a single product (e.g., polyphenols, ethanol, or active carbon) and without further utilization of the produced products. Besides, the economic information available about the production of value-added products from BSG is insufficient. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent. The objectives of the research detailed here were to 1) develop a process to simultaneously produce protein-rich (PP) and fiber-rich products (FP) from BSG, 2) assess the replacement of fishmeal with PP in shrimp feed, 3) evaluate the economics of the overall process of PP production at a commercial scale, and 4) explore the potential use of cellulose adsorbent obtained from the FP in removing heavy metals from contaminated water. To attain these objectives, BSG was first subjected to a wet fractionation process to produce PP and FP using different chemical/biological treatments, where the effects of sodium hydroxide, sodium bisulfite, and a protease (Alcalase) at different concentrations were investigated. Under the optimized conditions, the produced PP contained 46% protein and less than 1% fiber. The effectiveness of using PP to replace fishmeal at increasing levels (10–70%) was then evaluated by performing shrimp feeding trials. The results showed that up to 50% of fishmeal in shrimp feed can be replaced by PP without affecting shrimp growth and feed utilization. Moving forward, a techno-economic analysis was conducted to evaluate the economic feasibility of the production of PP. The experimental conditions and results were input into the process simulation model for determining the mass and energy flows. For a processing plant with a capacity of 590 t wet BSG per day, the minimum selling price of PP to achieve a 5% return was determined to be $1044/t, lower than the price of fishmeal, indicating that the use of PP to replace fishmeal in shrimp feed could potentially reduce shrimp farming cost. The utilization of FP will further improve the economic feasibility of the fractionation process. FP was sequentially treated by dilute acid, alkali, and bleach to produce purified cellulose fibers, which were then modified by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation to produce a cellulose adsorbent. The feasibility of the adsorbent in removing heavy metals (especially lead and manganese) from contaminated water was then investigated. Based on the results, the produced cellulose adsorbent showed high adsorption capacities for lead (272.5 mg/g) and manganese (52.9 mg/g). Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also offer alternative ways for the brewing industry to manage BSG.
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    Nutritional Value of Spent Hibiscus Calyces and Assessment of Consumers' Knowledge and Perception of Hibiscus Products for the Promotion of their Consumption
    Ndiaye, Oumoule (Virginia Tech, 2021-11-09)
    Hibiscus calyces have anti-inflammatory effects, reduce metabolic risk factors, and act as a prebiotic in the human gut. Bioactive compounds in hibiscus include dietary fiber, polyphenols and vitamins and hibiscus calyces have a well appreciated flavor. Preparation of juice from hibiscus is done using hot or cold aqueous maceration procedures. When hibiscus beverages are made, the remaining biomass, the spent calyces, is discarded. Little information is available on the composition of the spent calyces. To determine whether the spent calyces have potential value, it is important to evaluate the composition of major bioactive elements and other potentially valuable components like aromas. The overall goal of this work was to determine if hibiscus spent calyces have components that would be of nutritional value, and to investigate consumer interest in hibiscus consumption in the U.S. The first objective was to measure the contents of sugar, fiber, anthocyanins, other phenolics, vitamin C, and organic acids (hibiscus/garcinic, citric, succinic, fumaric acid) in spent calyces. The second objective was to identify and quantify flavor compounds in the spent calyces. The third objective was to assess American consumers knowledge and perception of hibiscus products. Cold and hot aqueous extractions were carried out on whole calyces of red and white hibiscus using a calyces:water ratio of 1:15. The spent calyces were freeze-dried and analyzed for sugar, fiber, anthocyanins, total phenolics, vitamin C, organic acids and flavor compounds and compared to whole calyces. Soluble and insoluble dietary fiber were measured using sequential enzymatic digestion and gravimetric filtration according to the AOAC method. HPLC was used to determine sugars, anthocyanins and vitamin C, acids. UPLC to identify polyphenols and GCMS with SPME to identify and quantify aroma compounds. Results of the survey show that most of the American consumers who participated in this study have consumed hibiscus products before and were aware of the health attributes of hibiscus products. The most liked products were tea and juices. Main reason for hibiscus consumption was in order: taste, health, flavor, and trend. The health statement provided to the participants of the survey did not affect their willingness-to-pay (WTP) for hibiscus beverages. Spent calyces contained significant amounts of sugars, anthocyanins, total phenolic, organic acids, vitamin C, dietary fiber, and aroma compounds. More fiber was found in the spent calyces than in the raw ones; volatiles profile and phenolics profile were similar to those of the raw calyces. These important nutritional compounds make hibiscus spent calyces useful as a functional ingredient in food products or for producing nutraceutical products. Use of spent calyces will increase value of hibiscus products benefit to both consumers and industrials and help reduce economic and environmental issues related to food waste management.
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    Role of dry beans (Phaseolus vulgaris L.) in binding bile salts and modulating lipid digestion: Impact of the bean matrix and high-hydrostatic pressure processing
    Lin, Tiantian (Virginia Tech, 2020-05-05)
    According to the American Heart Association, cardiovascular disease (CVD) is the leading cause of death in the U.S., representing about 20-30% of all deaths every year in the U.S. Major risk factors for developing CVD include high blood lipid and LDL-cholesterol levels. A large number of heart attacks and strokes could be prevented by controlling these factors through lifestyle modifications and diet interventions. Epidemiological evidence shows that consumption of dry or common beans (Phaseolus vulgaris L.) has positive effects on reducing blood LDL-cholesterol and lipid levels. These health benefits are mainly attributed to the high content of dietary fiber (DF) of beans, including soluble and insoluble DF (SDF and IDF). Some proposed mechanisms to explain the cholesterol and lipid-lowering effects of DF are related to the physico-chemical properties (e.g. viscosity) of DF, and involve binding to bile salts (BS) in the small intestinal to prevent BS re-absorption which further promote cholesterol catabolism and delay lipid digestion. Nevertheless, the precise mechanisms are not fully understood yet. In addition, cooking and processing operations, and in particular high-hydrostatic pressure (HHP) processing, can modify the composition, structure and functional properties of foods; however, whether HHP affects the ability of beans to interfere with different aspects of lipid digestion remains unknown. The overall goal of this research is to understand how common beans and HHP processing impact the ability of beans to bind BS and influence lipid digestion in vitro. The specific objectives are 1) to evaluate the effect of HHP treatments (and compared it with conventional cooking (HT)) on the thermo-rheological and functional properties of dry beans; 2) to identify the impact of major bean components on the in vitro BS-binding ability of beans, the role played by the bean matrix and how this is affected by HHP processing; 3) to investigate how bean (micro)structure and fiber fractions, as well as HHP processing of dry beans, influence lipid digestion in vitro. Results showed that HT caused complete starch gelatinization and protein denaturation of beans, while HHP treatments induced partial or no starch gelatinization and a lower degree of protein denaturation, which resulted in enhanced protein solubility and emulsifying activity/stability. It was observed that, while HT treatment reduced the capacity of bean flours to retain BS because of severe disruption of the bean cell wall integrity, protein matrices, and starch granules, HHP treatments maintained or enhanced BS retention, possibly by promoting the formation of starch/protein/fiber networks able to entrap BS. Furthermore, by using an in vitro dialysis-based digestion model combined with viscosity measurements and thermal analysis, it was shown that the interaction between bean tissue materials and primary BS was not only related to viscosity but also involved hydrophobic linkages. The contribution of IDF and proteins (other than SDF) to retain BS was also significant. There was a different binding preference of beans to four primary BS with sodium glycochenodeoxycholate, the more hydrophobic BS, showing the largest retention levels while sodium taurocholate being the least effectively retained BS by beans. Diverse sequences of the same processing operations showed distinct impacts on BS-retention by dry beans. By means of an in vitro digestion model simulating conditions in the upper gastrointestinal tract, bean flours delayed the digestion of extrinsic lipids to a higher extent, compared to isolated IDF and SDF. Furthermore, HHP treatment and less severe mechanical disintegration maintained the ability of beans to modulate lipid digestion, which suggests the importance of bean structural integrity in reducing the lipolysis rate and extent by beans. Overall, this research work shows that HHP processing is a promising minimal processing technology to produce bean flours with improved functionality. It also highlights the importance of considering the structure of foods, and not just their nutrient content, when evaluating potential health impacts. This knowledge could be applied to develop a range of bean-based ingredients and formulations with desirable health benefits. This work can be extended to research the influence of beans on the gut microbiota and profile of secondary BS and short-chain fatty acids, which are also closely related to cholesterol and lipid metabolism.