Abstract Epidemiological data suggest that consumption of coffee and tea is associated with a reduced risk of several chronic and degenerative diseases including cardiovascular disorders, diabetes, ...obesity and neurodegenerative disorders. Both coffee and tea are a rich source of phenolic compounds including chlorogenic acids in coffee; and flavan-3-ols as well as complex theaflavins and thearubigens in tea. Coffee and tea are two of the most commonly consumed beverages in the world and thus represent a significant opportunity to positively affect disease risk and outcomes globally. Central to this opportunity is a need to better understand factors that may affect the bioavailability of specific phenolic components from coffee and tea based beverages. An overview of the phenolic composition of coffee and tea is discussed in the context of how processing and composition might influence phenolic profiles and bioavailability of individual phenolic components. Specifically, the impact of beverage formulation, the extent and type of processing and the influence of digestion on stability, bioavailability and metabolism of bioactive phenolics from tea and coffee are discussed. The impact of co-formulation with ascorbic acid and other phytochemicals are discussed as strategies to improve absorption of these health promoting phytochemicals. A better understanding of how the beverage composition impacts phenolic profiles and their bioavailability is critical to development of beverage products designed to deliver specific health benefits.
Chlorophyll, a phytochemical responsible for the green pigmentation in plants, has been studied for almost 100 years for its biological activities in humans. Over the past 30 years, the potential ...chemopreventative activities of both natural chlorophylls and their processed induced derivatives as well as the semisynthetic forms, such as sodium copper chlorophyllin, have been the focus of many research efforts. Established as potential chemopreventative agents with little to no bioavailability themselves, the activities of chlorophyll derivatives were generally ascribed to their ability to modulate mutagen/carcinogen bioavailability, their metabolism, and ultimately their ability to decrease the “exposure” to these carcinogens for humans at risk. More recently, systemic activities of chlorophyll derivatives have been reported to include modulation of oxidative stress and regulation of xenobiotic metabolizing systems and gene expression of systems critical to prevention of initiation and/or progression of cancer including NFE2-related factor 2, nuclear factor kappa B, TGF-β, and β-catenin pathways. With this in mind, the goals of this review are to provide an update to the comprehensive review of Ferruzzi and Blakeslee (2007) to include new insights into the behavior of chlorophyll derivatives in the gut as well as evidence of the systemic bioavailability of chlorophyll derivatives and their metabolites in support of potential impacts in prevention of cancer throughout the body.
•Two classes of starch digestive enzymes can be selectively inhibited by flavonoids.•Structural inhibition requirements of flavonoids for the enzymes were identified.•Flavonoids occupy catalytic ...active sites of the enzymes to inhibit their activity.
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 digestive enzymes was confirmed through various analytical techniques - in vitro inhibition assay, fluorescence quenching, kinetic study, and molecular modeling. Considering the chemical structure of flavonoids, the double bond between C2 and C3 and OH groups at A5 and B3 are critical for the inhibition of α-amylase allowing flavonoids to lie parallel on the α-amylase catalytic active site, whereas the OH groups at B3 and C3 are important for α-glucosidase inhibition causing B-ring specific entry into the catalytic active site of α-glucosidase. Our findings provide insights into how to apply flavonoids to effectively control digestion rate for improving physiological responses.
•Banana pulp postharvest processing impacts its fiber content and phenolic profile.•Freeze-drying preserves higher amount of epicatechin than oven-drying.•Banana phenolic acids and flavonols were ...found to be more thermally stable.•Oven-drying and extrusion improve the extraction of flavonols and phenolic acids.•Freeze-drying leads to native banana flours rich in insoluble dietary fiber.
Use of banana flours as functional ingredients is growing due to their nutritional benefits derived from phenolics and dietary fiber. However, the effect oven-drying, freeze-drying and extrusion on the phenolic compounds or starch digestibility is not understood. In this work, phenolic acids (gallic acid, caffeic acid), flavan-3-ols (epicatechin, catechin) and flavonols (quercetin-3-O-glucoside and myricetin) were quantified in banana flour processed by different methods. Epicatechin, the most abundant phenolic in all flours (up to 1.93 mg/100 g), was significantly reduced during thermal processing (oven-drying and extrusion). Meanwhile, phenolic acids and flavonols were found to be more thermally stable. Thus, oven-drying and extrusion generally improved the extractability of phenolic acids and flavonols. Freeze-drying resulted in native flours with significantly higher insoluble dietary fiber (up to 43.3%), although the digestible starch fraction was digested more rapidly than the oven-dried counterpart.
Maize is a staple crop that has been the subject of biofortification efforts to increase the natural content of provitamin A carotenoids. Although significant progress toward increasing provitamin A ...carotenoid content in maize varieties has been made, postharvest handling factors that influence carotenoid stability during storage have not been fully established. The objectives of this study were to determine carotenoid profiles of six selected provitamin A biofortified maize genotypes at various developmental stages and assess the stability of carotenoids in maize kernels during controlled storage conditions (12 month period), including elevated temperature and relative humidity. There were no significant changes in the content of individual carotenoids within genotypes during kernel development from 45 days after pollination through the time of harvest. Carotenoid losses through traditional grain drying were also minimal (<9%). However, the stability of carotenoids in maize kernels over storage time after harvest was found to be dependent on both temperature and humidity, with variation observed among genotypes. Different forms of provitamin A carotenoids follow similar degradation rates. The genotype C17xDE3 had a degradation rate 2 times faster than those of the other genotypes evaluated (P < 0.001). These differences in carotenoid stability under controlled storage were attributed, in part, to observed differences in the physical properties of the kernels (surface area and porosity). These results support the notion that effective control of moisture content and temperature of the kernels during storage conditions is essential to reduce the speed of degradative reactions.
Abstract The growing body of epidemiological and experimental evidence associating diets rich in fruits and vegetables with prevention of chronic diseases such as cancer has stimulated interest in ...plant food phytochemicals as physiologically active dietary components. Chlorophyll and its various derivatives are believed to be among the family of phytochemical compounds that are potentially responsible for such associations. Dietary chlorophyll is predominantly composed of lipophilic derivatives including chlorophyll a and b (fresh fruits and vegetables), metal-free pheophytins and pyropheophytins (thermally processed fruits and vegetables), as well as Zn-pheophytins and Zn-pyropheophytins (thermally processed green vegetables). Water-soluble derivatives including chlorophyllides, pheophorbides, as well as a commercial-grade derivative known as sodium copper chlorophyllin (SCC) also contribute to the diversity of dietary chlorophyll derivatives. Although the use of chlorophyll derivatives, especially SCC, in traditional medical applications is well documented, it is perhaps the potential of chlorophyll as a cancer preventative agent that has drawn significant attention recently. Biological activities attributed to chlorophyll derivatives consistent with cancer prevention include antioxidant and antimutagenic activity, mutagen trapping, modulation of xenobiotic metabolism, and induction of apoptosis. Although most research has focused on commercial-grade SCC, the extent to which natural chlorophyll derivatives modulate biomarkers of cancer risk is also being explored. Recent research efforts have also included investigation of the impact of digestive factors on chlorophyll structure and bioaccessibility as a means to better understand the extent to which these pigments may be bioavailable in humans and therefore have more systemic impact in the prevention of cancer.
•Starch-phenolic acid complexation is primarily driven by physical interaction.•Physical complexation between starch and phenolics persists after gelatinization.•Phenolic complexation results in ...reduced hydrodynamic radii of gelatinized starch granules.•Complexation alters both pasting properties and digestibility of starch.
Leveraging phenolic complexation to optimize starch functionality and digestibility is restrained by the obscurity of their physicochemical nature and molecular basis. To define starch-phenolic complexes under hydrothermal treatments, maize amylopectin and potato starch were complexed with caffeic acid, ferulic acid and gallic acid. Starch hydrothermal stability and digestibility were measured by differential scanning calorimeter and Englyst’s method, respectively. While monosaccharide compositions and glycosidic linkages were analyzed by GC–MS, hydrodynamic radius and proton magnetic resonance of gelatinized complexes were measured by dynamic light scattering and NMR respectively. Compared with native starches, starch-phenolic complexes were not chemically modified and had modestly lower estimated glycemic indexes and significantly lower gelatinization temperatures (p < 0.05). Starch-phenolic complexes also had significantly lower levels of phenolic proton intensities and hydrodynamic radii relative to the control starch-phenolic mixtures (p < 0.05). These results suggested that phenolics may complex with starch through non-covalent CH-π bonds along α-(1 → 4) glycosidic chains.
Many of the potential health benefits of flavonoids have been associated with their specific chemical and biological properties including their ability to interact and bind non-covalently to ...macronutrients in foods. While flavonoid-protein interactions and binding have been the subject of intensive study, significantly less is understood about non-covalent interactions with carbohydrates and lipids. These interactions with macronutrients are likely to impact both the flavonoid properties in foods, such as their radical scavenging activity, and the food or beverage matrix itself, including their taste, texture and other sensorial properties. Overall, non-covalent binding of flavonoids with macronutrients is primarily driven by van der Waals interactions. From the flavonoid perspective, these interactions are modulated by characteristics such as degree of polymerization, molecular flexibility, number of external hydroxyl groups, or number of terminal galloyl groups. From the macronutrient standpoint, electrostatic and ionic interactions are generally predominant with carbohydrates, while hydrophobic interactions are generally predominant with lipids and mainly limited to interactions with flavonols. All of these interactions are involved in flavonoid-protein interactions. While primarily associated with undesirable characteristics in foods and beverages, such as astringency, negative impact on macronutrient digestibility and hazing, more recent efforts have attempted to leverage these interactions to develop controlled delivery systems or strategies to enhance flavonoids bioavailability. This paper aims at reviewing the fundamental bases for non-covalent interactions, their occurrence in food and beverage systems and their impact on the physico-chemical, organoleptic and some nutritional properties of food.
The degradation behaviors of catechins in dilute aqueous systems, including tea beverages and catechin solutions, have been documented; however, their reaction kinetics in green tea concentrated ...solutions, and impacts of pH, concentration, and temperature thereon, have not yet been established. In this study, reactions were conducted at pH levels ranging from 1.5 to 7, concentrations ranging from 1 to 1666.7 mg/mL, and temperatures ranging from 25 to 120 °C. Catechin contents were determined using high-performance liquid chromatography. Catechins were found to be more stable at high concentrations around pH 4. An empirical model for catechin content was established as a function of pH and temperature and showed good correlation between green tea concentrated solutions and previous reports of catechin stability in powder systems. These results provide useful approaches for shelf life calculations and catechin loss predictions at given temperature and pH conditions in green tea concentrates.
Potatoes (Solanum tuberosum) are an important global crop that can be transformed into many products impacting several health dimensions ranging from undernutrition, food security and disease ...prevention to issues of overnutrition including obesity, diabetes, heart disease. Processed potato products are typically categorized as high fat and sodium foods, as well as being classified as a significant source of carbohydrate, in the form of starch. Conversely, potato products are less known for their contribution of key micronutrients (vitamin C, potassium, magnesium), fiber, and phytochemicals (phenolics and carotenoids). More recent insight into the nutritional value of potatoes and the potential of potato phytochemicals to modulate oxidative and inflammatory stress as well as the potential to alter glycemic response has resulted in increased interest in strategies to improve and leverage the nutritional quality of processed potatoes. This review summarizes critical information on nutritional profiles of potatoes and their processed products and describes the state of the science relative to the influence of in-home and common commercial processing on nutritional quality and potential impacts on human health.
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