
Luke HowardUniversity of Arkansas at Fayetteville | U of A · Department of Food Science
Luke Howard
Ph.D. Food Science, Professor
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Publications (204)
Processing of berries usually degrades anthocyanin and non-anthocyanin phenolics and diminishes antioxidant activity. In Colombia, jelly produced from the fruit of Vaccinium meridionale Swartz is a popular product among consumers. The aim of this study was to determine the effect of jelly processing steps on bioactive components. Analysis of anthoc...
Polyphenols have been extensively profiled and quantified in commercially grown berries, but similar information is sparsely available for wild berries. Because polyphenolic contents are inherently associated with berries health benefits, determining phenolic profiles is an important step for strategizing potential uses by the industry and for heal...
Berry volatiles are responsible for the berry aroma but there is limited information available on the health-promoting activities of berry volatiles. The objectives of this study were to evaluate the chemical composition of volatile extracts from black raspberries, blueberries, and blackberries and investigate their antiproliferative effect and apo...
Volatile compounds in fruits are responsible for their aroma. Among fruits, berries contain many volatile compounds, mainly esters, alcohols, terpenoids, aldehydes, ketones, and lactones. Studies for volatile compounds in berries have increased extensively as the consumption of berry products rapidly increased. In this paper, we reviewed biosynthes...
Objectives
The anti-inflammatory effects of berries have been attributed to their polyphenol content. In vitro models of activated murine macrophages have shown that volatiles in berries exert anti-inflammatory effects as well. However, human data in this area are scarce. To address this limitation we measured the effects of wild-blueberry phenolic...
Objectives
Berry volatiles are responsible for the flavor and aroma of berries. Berry volatiles has been recently reported to have an anti-inflammatory effect. However, there is still limited information available on the health-promoting activities of berry volatiles. The objectives of this study were to evaluate the chemical composition of volatil...
Muscadine grapes (Vitis rotundifolia Michx.) are a specialty crop cultivated in the southern United States. Muscadines (2n = 40) belong to the Muscadinia subgenus of Vitis, while other cultivated grape species belong to the subgenus Euvitis (2n = 38). The muscadine berry color locus was mapped to a 0.8 Mbp region syntenic with chromosome 4 of V. vi...
Canned beans are a convenient, safe, and nutritious food consumed worldwide. A typical dry bean canned product processing involves following steps: hydration or soaking, blanching, filling, adding brine or sauce, sealing/closing, and thermal (retort) processing. Dry beans are primarily processed in a variety of canned forms/packs. Thermal processin...
The anti-inflammatory activity of blackberries has been attributed to phenolic compounds, especially anthocyanins. The present study hypothesized that volatiles could contribute to anti-inflammatory activity as well. The anti-inflammatory properties of three blackberry genotypes varying in total volatile and phenolic contents were assessed by measu...
Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of pro-inflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidan...
Red drupelet reversion (RDR) is a postharvest disorder of blackberries ( Rubus L. subgenus Rubus Watson) in which fully black drupelets revert to red after harvest. This disorder can negatively impact consumer perception of fresh-market blackberries. The cause of RDR is hypothesized to be related to intracellular damage sustained because of mechani...
Objectives
Berry volatiles are primary or secondary compounds produced when tissue disrupts, and responsible for the flavor and aroma of berries. Berry volatiles has been recently reported to have anti-inflammatory effect. Acute lung injury is one of the severe consequences of lung inflammation increasing respiratory stress and pulmonary edema with...
Berries are a rich source of phytochemicals, especially phenolics well known for protective activity against many chronic diseases. Berries also contain a complex mixture of volatile compounds that are responsible for the unique aromas of berries. However, there is very limited information on the composition and potential health benefits of berry v...
Muscadine grapes ( Vitis rotundifolia Michx.) are a specialty crop cultivated in the southern United States. Muscadines (2n=40) belong to the Muscadinia subgenus of Vitis , while all other cultivated grape species belong to the subgenus Euvitis (2n=38). The berry color locus in muscadines has been mapped to a 0.8 Mbp region syntenic with chromosome...
[This corrects the article DOI: 10.1016/j.heliyon.2020.e03845.].
Objectives
Sweetpotato leaf (SPL) is a natural source of phenolic compounds with potential utility as an antioxidant. The study aimed to measure the impacts of the years on SPL total phenolic content and antioxidant capacity and to identify and quantify the individual phenolic compounds.
Methods
Sweetpotato leaves in 2018 (27 varieties) and 2019 (...
To encourage children to frequently consume wild blueberries as part of their dietary patterns, incorporating blueberry powder into specific foods may be an effective strategy. Thus, it is important to determine appropriate types of food products that both minimize food processing-induced loss of beneficial components of blueberries (e.g., anthocya...
Berries of Vaccinium meridionale Swartz contain a variety of phytochemicals, which are believed to account for their bioactive properties. The potential of Vaccinium meridionale Swartz pomace as a source of bioactive compounds was investigated. The dietary fiber (DF) content was assessed by the AOAC method, phenolic compounds were characterized and...
Wild blueberry (WBB) powder can be added to the formulation of foods to encourage consumption of health-promoting polyphenolics, but the stability of polyphenolics throughout storage is important. We determined the stability of polyphenolics in five products (ice pop, oatmeal bar, graham cracker cookie, juice, and gummy product) prepared with WBB p...
Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The...
Red radish anthocyanins are relatively stable due to the acylation of anthocyanins with organic and phenolic acid moieties. The objective of this study was to create and identify a novel ethyl-bridged acylated anthocyanin with a stable violet color from red radishes in the presence of acetaldehyde and catechin. After incubation at ambient temperatu...
Cranberry volatiles have received little attention for health-promoting properties. In this study, we compared the inhibitory effects of cranberry polyphenol and volatile extracts and volatile standards on nitric oxide (NO) production in lipopolysaccharide (LPS) activated RAW 264.7 macrophages. Polyphenols were analyzed by HPLC/HPLC-MS and volatile...
This review explores the entrance of glyphosate into the food supply and its impact on human health, along with the incidental impact on the honey supply and bees. Currently, glyphosate is the most widely used herbicide worldwide as well as the most politicized and publicized herbicide. The debate on the use of glyphosate has been prompted by the c...
Awareness of the human health benefits of blueberries is underpinned by a growing body of positive scientific evidence from human observational and clinical research, plus mechanistic research using animal and in vitro models. Blueberries contain a large number of phytochemicals, including abundant anthocyanin pigments. Of their various phytochemic...
Bioactive anthocyanins from aqueous extracts of muscadine grape pomace were concentrated using osmotic distillation (OD) and direct contact membrane distillation (DCMD) using polypropylene (PP) and poly(ethylene chlorotrifluoroethylene) (ECTFE) membranes. The driving force for OD is created by using a high concentration brine solution while the dri...
Tart cherries have been reported to exert potential health benefits attributed to their specific and abundant polyphenol content. However, there is a need to study the impact and fate of tart cherries polyphenols in the gut microbiota. Here, tart cherries, pure polyphenols (and apricots) were submitted to in vitro bacterial fermentation assays and...
This chapter reviews trends in canned bean production and consumption, processing factors influencing quality, grade standards for canned beans, quality evaluation methods, and future trends in bean product development and novel packaging concepts. It lists different regions and countries where dry beans are grown and consumed. Beans typically requ...
Fresh-market blackberries ( Rubus subgenus Rubus Watson) have a growing global market, with continued release of cultivars to meet demand for consumer-quality fruit. The release of primocane-fruiting blackberry plants that produce crops on both floricanes and primocanes has expanded blackberry production. This study investigated the physiochemical...
Polyphenols extracted from blueberry (Vaccinium corymbosum) pomace were concentrated using nanofiltration. Crossflow filtration was shown to be a feasible method for concentrating the polyphenols present in dilute aqueous solutions. High-performance liquid chromatography was employed for the determination of total anthocyanins, total flavonols and...
Blackberry anthocyanins provide attractive color and antioxidant activity. However, anthocyanins degrade during juice processing and storage, so maintaining high anthocyanin concentrations in berry juices may lead to greater antioxidant and health benefits for the consumer. This study evaluated potential additives to stabilize anthocyanins during b...
Java plum (Syzygium cumini Lam.) is a rich source of polyphenolics with many purported health benefits, but the effect of maturation on polyphenolic content is unknown. Freeze-dried samples of Java plum from seven different maturity stages were analyzed for anthocyanin, flavonol, flavanonol and hydrolysable tannin composition by HPLC. Anthocyanins...
BACKGROUND: Since the consumption of fresh blackberries has increased, the demand for new cultivars with extended postharvest quality that meet consumer expectations has increased. OBJECTIVE: The objective of this study was to identify fresh-market blackberry genotypes with high postharvest potential and evaluate changes in physiochemical and senso...
Blackberries (Rubus subgenus Rubus Watson) are grown worldwide for commercial fresh markets. Physiochemical and sensory attributes were evaluated on fresh fruit of five blackberry cultivars (Natchez, Osage, Ouachita, Prime-Ark® 45, and Prime-Ark® Traveler) and six advanced breeding selections from the University of Arkansas Fruit Breeding Program....
BACKGROUND: Products derived from black chokeberry are claimed to be beneficial in treating chronic diseases, such as obesity and diabetes.
OBJECTIVE: The objective of this study was to determine if supplementation with Aronia melanocarpa (black chokeberry) juice concentrate (AJC) has anti-obesity properties in mice fed obesogenic diets.
METHODS: M...
This work reports a novel method of recovering anthocyanin compounds from highly-pigmented grapes via a fermentation based approach. It was hypothesized that batch growth of Zymomonas mobilis on simple medium would produce both ethanol and enzymes/biomass-acting materials, the combination of which will provide a superior extraction when compared to...
The vitamin E analogs δ-tocotrienol (DT3) and γ-tocotrienol (GT3) have significant protective and mitigative capacity against the detrimental effects of ionizing radiation (IR). However, the expense of purification limits their potential use. This study examined the tocotrienol-rich fraction of rice bran (TRFRB) isolated from rice bran deodorizer d...
Gamma (γ-T3) and delta (δ-T3) tocotrienols are the most potent natural protective agents against harmful effects of radiation exposure and there is substantial interest in advancing these tocols toward Food and Drug Administration approval. However, co-administration with alpha tocopherol is reported to interfere with the radioprotective properties...
The black-skinned cultivar Southern Home is noteworthy due to its extreme disease resistance, attractive leaves, and unique fruit shape. ‘Southern Home’ is a complex hybrid of several Vitis species including V. rotundifolia (Michx.), V. popenoei (Fen.), V. munsoniana (Sims.), and V. vinifera (L.). The first three species are all from the Muscadinia...
Muscadine grapes (Vitis rotundifolia Michx.) are native to the southeastern United States and have potential for greater fresh-market sales if postharvest storage can be improved, but limited information is available on postharvest storability. In 2012 and 2013, physiochemical and storability attributes were measured in 17 muscadine genotypes (sele...
Fresh-market muscadine (Vitis rotundifolia Michx.) cultivars, such as ‘Supreme’, have reportedly improved
postharvest storability. Physiochemical attributes and nutraceutical compounds in ‘Supreme’ muscadine whole
grape berries and grape segments (flesh [skin and pulp] and seeds) were measured at harvest in 2012 and 2013
and nutraceutical compounds...
A major limiting factor in fresh-market muscadine grape (Vitis rotundifolia Michx.) commercialization is fruit deterioration during storage. Research on table grapes has shown that field fungicide applications increase storability, but little is known of their effect on muscadines. The effect of field applications of fungicides on
physicochemical a...
A great deal of attention has been focused on the potential health benefits of using rice bran oil because it is a rich source of bioactive compounds. Rice bran oil deodorizer distillate (RBODD) is a byproduct obtained from distillation of rice bran oil. Elevated plasma cholesterol level is one of the major risk factors for coronary heart disease....
BACKGROUND: Strawberry puree color is unstable during processing and storage due to oxidative reactions. OBJECTIVE: To determine if strawberry puree prepared under nitrogen or carbon dioxide would result in greater retention of color and anthocyanins than samples prepared under air. METHODS: Purees prepared under carbon dioxide, nitrogen or air wer...
Phenolic compounds from berries have shown bone protective effects in animal studies. We hypothesized that consumption of 45 g of blackberries or blueberries for 9 months will prevent smoking-induced bone loss in postmenopausal women. Postmenopausal smokers (n = 45) and nonsmokers (n = 20) were recruited. Smokers were randomly assigned to treatment...
Muscadine (Vitis rotundifolia Michx.) grapes have some of the highest nutraceutical levels among fruit. Field fungicide applica- tions have been shown to influence nutraceutical concentrations of other functional foods, but little is known of their affect on muscadine grapes. The effect of field applications of fungicides on nutraceutical concentra...
Chokeberries are an excellent source of polyphenols, but their fate during juice processing and storage are unknown. The stability of anthocyanin's, total proanthocyanidins, hydroxycinnamic acids, and flavonols at various stages of juice processing and over six months of storage at 25 oC were determined. Flavonols, total proanthocyanidins and hydro...
Dietary polyphenolics can be converted into smaller phenolic acids (PA) by microorganisms in the colon and may contribute to health benefits associated with the parent polyphenolics Urinary excretion of 18 PA and their conjugates were studied, using HPLC/MS/MS, in rats fed AIN93G based diets containing 5% (dry weight basis) of either cranberry (CB)...
Fresh market blackberries can feel "seedy" when consumed. This "seediness" is associated with the presence of pyrenes which are comprised of a single seed enclosed in an endocarp. Small pyrene size (<3 mg) is preferred in both fresh-market and processed blackberry products. Yet, the proportion of pyrene weight to total berry weight can be more impo...
Expanding interest in the nutraceutical market inspires sensory‐ and nutraceutical‐oriented optimization methods. Black cherry ( BlkCh ), C oncord grape ( C on) and pomegranate ( P om) juices were blended according to a mixture design (seven juice treatments) and evaluated by descriptive and consumer panels. Consumers ( n = 100) evaluated estimated...
Products derived from black chokeberry are claimed to be beneficial in diseases associated with oxidative stress due to high concentrations of anthocyanins and procyanidins, which possess strong antioxidative potential. Extracts from black chokeberries have been demonstrated to have anticancer, cardioprotective, and anti‐diabetic effects. The purpo...
Interest in potential health-promoting properties of phytochemicals has led to a wealth of information about the various extraction, purification, and identification techniques for these compounds. Pressurized liquid extraction, supercritical fluid extraction, ultrasound-assisted extraction, microwave-assisted extraction, and matrix solid-phase ext...
Chokeberry anthocyanins are susceptible to degradation during processing and storage of processed products. In this study we determined the effects of three pH levels (2.8, 3.2, and 3.6) and four beta cyclodextrin (BCD) concentrations (0, 0.5, 1, and 3%) alone and in combination on the stability of chokeberry juice anthocyanins before and after pas...
The constant fight against aging increases the demand for products that have the potential to promote health. Dark-pigmented fruits such as blackberries, blueberries and Concord grapes show potential to fulfill this demand. Four techniques (response surface, ideal point, desirability function and intuition) were used to optimize a mixture of blackb...
Phytochemical-rich fruits may have health-related properties, which make juices of these fruits prime candidates for the nutraceutical market. Understanding consumer acceptance and compositional, color, and descriptive sensory changes during storage is crucial to the success of nutraceutical-rich juices. Juices (blackberry, blueberry, and Concord g...
Canned dried beans are a convenient, safe, and nutritious food that is consumed world-wide. The development of new food products containing beans will drive an increased consumption as will increased offerings of bean products in convenient easy-to-open and prepare retortable packages. Additionally, validation of the health-promoting properties of...
As human life expectancy increases, the potential for nutraceutical products expands. Economic theory and sensory science were integrated to determine (1) consumer acceptance of potential health statements about a juice blend and (2) the relative satisfaction consumers derived from sensory and nutraceutical characteristics of a juice blend. Four no...
An experiment was conducted to study the protective effect of feeding extruded and unextruded blueberry pomace (BBP) on selected metabolic parameters associated with metabolic syndrome in a model of high fructose (HF)-fed growing Sprague-Dawley rats. Treatments were as follows: (1) control (modified AIN-based diet); (2) HF diet (AIN diet with 58% f...
Wine consumers are interested in components of red wines that contribute to health effects, flavor, and color. Three Vitis vinifera wines (Cabernet Sauvignon, Merlot, and Zinfandel) were blended using formulas created by an augmented simplex centroid mixture design, resulting in 10 wines (three single-component wines, three binary blends, and four...
Grape pomace contains appreciable amounts of polyphenolic compounds such as anthocyanins and procyanidins which can be recovered for use as food supplements. The extraction of these polyphenols from the pomace is usually accomplished at slightly elevated temperatures, frequently employing hydroethanolic solvents. Due to governmental regulations and...
Estrogen loss predisposes postmenopausal women to a 60% greater risk of developing metabolic syndrome. We examined the dose dependent effects of whole blackberries containing 87% cyanidin-3-O-β-d-glucoside (C3G), a powerful antioxidative and anti-inflammatory anthocyanin, in ovariectomized rats. Nine-month-old female Sprague–Dawley rats were either...
As human life expectancy increases, the potential for nutraceutical products
expands. Economic theory and sensory science were integrated to determine (1)
consumer acceptance of potential health statements about a juice blend and (2)
the relative satisfaction consumers derived from sensory and nutraceutical characteristics
of a juice blend. Four no...
Anthocyanins may be responsible for the health benefits of chokeberries, as they are present in large quantities in chokeberries and are potent antioxidant and anti‐inflammatory agents. Previous investigations on the bioavailability of anthocyanins illustrate that little of the ingested amount reaches systemic circulation. Furthermore, anthocyanins...
Anthocyanins and tannins in blueberries, blackberries and black raspberries are susceptible to degradation during processing, with juices showing the greatest losses due to physical removal of skins and seeds. Anthocyanins and procyanidins are also degraded in processed products stored at ambient temperature with losses accompanied by increased pol...
Blackberry (Rubus sp.) fruit contains high levels of anthocyanins and other phenolic compounds, mainly flavonols and ellagitannins, which contribute to its high antioxidant capacity and other biological activities. Blackberry phenolic composition and concentrations are known to be influenced by genetics, growing conditions, and maturation. Despite...
The effect of feeding grape pomace on certain metabolic parameters associated with high fructose (HF) feeding was studied. Forty male growing Sprague-Dawley rats were randomly assigned into groups: (1) control; (2) HF; (3) HF with low-level (1.5% of diet) grape pomace (HF+LP), and (4) HF with high-level (5.0% of diet) grape pomace (HF+HP). The HF+L...
Juice is the most common form in which cranberries are consumed; however there is limited information on the changes of polyphenolic content of the berries during juice processing. This study investigated the effects of three different pretreatments (grinding plus blanching; only grinding; only blanching) for cranberry juice processing on the conce...
Infinite dilution diffusion coefficients of certain phenolic compounds were measured as a function of temperature in water slightly acidified with formic acid using the Taylor dispersion method. The diffusion coefficients calculated using the chromatographic peak broadening technique were found to increase exponentially with an increase in the temp...
Flavonoids present in freeze-dried Sunbelt (Vitis labrusca L.) grape pomace were extracted at a pressure of 10.3 MPa and temperatures between 60 and 140C using pressurized hydroethanolic solvents (0, 40, 80% v/v ethanol in water) acidified with organic acids (formic, acetic, citric and tartaric acid at a pH of 2.5). Acetic acid had a significant ef...