Nutrition & Food Science

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RELATIONSHIPS BETWEEN LEADERSHIP AND SELF-ESTEEM CHARACTERISTICS OF PARAPROFESSIONALS AND NUTRITIONAL CHANGE IN A CLIENT SAMPLE
(1974) Poffenberger, Linda L.; Longest, James W.; Nutrition & Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The study investigates the nature of the relationships between leadership and self-esteem attributes of a population of paraprofessionals and nutritional change based on records from a client sample. Sixty-five nutrition aides serving in the Expanded Food And Nutrition Education Program in Maryland and 397 program families are the subjects of the study. A survey technique was employed to gather leadership and self-esteem data for the aides and socioeconomic and nutritional data from records on a sample of client families. Relationships were hypothesized between leadership and nutritional change and self-esteem and between self-esteem and nutritional change. Non-parametric techniques were used in data analyses. Chi square and gamma coefficient were computed to determine the association between variables. The socioeconomic and nutritional characteristics of the aides and families and the relationship between family nutritional and demographic characteristics were described. Findings reveal a client group whose diets have shown improvement. Client demographic and nutritional characteristics seem independent of one another. There is little relationship between the client nutritional levels and aide characteristics. Hypothesis testing showed the leadership and self-esteem attributes of aides to be generally unrelated to the nutritional change of clients. It is concluded that the variables under study generally bear no relationship to one another. However, the exploratory nature of this study suggests it is an inadequate basis on which to evaluate paraprofessional role performance or the program. Many questions are raised and refinement and re-direction of study techniques are recommended as areas for future study.
Age, Nutrition, and Bone Metabolism: Analyses of Effects Using a Short-Term In Vivo Bone Model
(1987) Sinha, Rashmi; Soares, Jos; Nutritional Sciences Program; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The preventative effects of dietary calcium, zinc, and vitamin D metabolites on the net loss of bone were assessed using rats of different ages. Biochemical changes were monitored in femurs, humeri, mandibles, scapulas, and tibias. In addition femora were sectioned into epiphyses-metaphyses and diaphyses to evaluate nutritional influences on the trabecular and cortical type bone. since measurable bone degradation due to aging and nutritional status requires long period of time, a short-term in vivo system was developed to simultaneously examine bone formation and resorption. The system consisted of subcutaneous implantation of demineralized (DB) and mineralized (MB) bone powders. There was evidence of bone formation and resorption in the DB and MB implants respectively, as assessed by marker enzyme (formation-alkaline phosphatase; resorption-acid phosphatase) activities, mineral concentrations, radioisotope incorporation, and histological studies. The results indicated that several different bone samples are required to adequately predict changes occurring in the skeletal system. The epiphysesmetaphyses of long bone is a useful sample site examining changes occurring in trabecular bone while the diaphysis can assess cortical bone status. There was decreased bone formation and resorption as assessed by alkaline and acid phosphatase activity in the MB and DB implants in the 24 month-old rats as compared to 2 month-old rats. Dietary calcium and zinc levels did not affect the overall status of the bones and implants in the aged rats. Conversely, in 2 month-old rats dietary calcium at 1.0% stimulated bone formation in the DB implant, whereas 0.2% calcium increased bone resorption in the MB implants. Furthermore, 75 ng dietary 1,25-dihydroxycholecalciferol (l,25(OH) 2 D) per day increased resorption in MB implant and inhibited mineralization of DB implants in the young rats. Dietary zinc at 300 ppm reduced bone calcification in 2 month-old. The results of these studies indicated that neither high levels of dietary calcium, nor zinc, act as prophylaxes to counteract bone loss due to aging. The dietary use of l,25(OH) 2 D in old animals needs to be investigated further, since results in young animals are contradictory with reports in older rats.
THE EFFICACY OF A BOILING WATER BLANCH ON THE INACTIVATION OF LISTERIA MONOCYTOGENES IN DICED CELERY
(1990) Losikoff, Mary Bohrer; Westhoff, Dennis C.; Nutrition & Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The effect of a boiling water blanch on the thermal inactivation of Listeria monocytogenes in raw diced celery was investigated. L. monocytogenes, Scott A was heated in Tryptic Soy Broth with 0.6% yeast extract, pH 5.3, at 52, 54, 56, 58, and 59°C. D values were 13.33, 7.75, 1.29, 0.792, and 0.701 min, respectively. A predicted D value at 60°C = 0.36 min was obtained using a z value of 5. These thermal inactivation characteristics were subsequently used to evaluate the L. monocytogenes was recovered from inoculated (1 X 10^7 cells/g) diced raw celery after heating for 0.25 min in a laboratory boiling water blanch. Viable cells were not recovered after 0.5 min of heating. Heat penetration data for diced raw celery during a boiling water blanch were obtained in a commercial setting. These data were analyzed by the general method to determine the cumulative lethality at reference temperatures of 60°C using a z of 5 and, 70 and 71.7°C using a z of 10. It was determined that a recommended process of 2 min at 70 °C was reached in 80 sec during the blanch. Based on the findings of this study, a boiling water blanch could be used as part of the hurdles approach to eliminate L. monocytogenes from raw diced celery.
EFFECT OF PLANTING TIME AND LOCATION ON THE ISOFLAVONE CONTENT AND PROFILE OF DIFFERENT SOYBEANS [Glycine max (L.) MERRILL] CULTIVARS
(2003-12-12) Figallo, Victor Bernardo; Giusti, Maria M; Food Science
Isoflavones found in high concentrations in soybeans have received great attention due to their potential beneficial effects in human health. The effects of soybean planting time, location and seed type on isoflavone content and profile were evaluated using 40 cultivars. Isoflavones were extracted with 80% methanol and analyzed by HPLC. Conditions were optimized to separate all reported soybean isoflavones plus an additional acylated genistein-related peak. Genistein derivatives were most abundant, followed by daidzein and glycitein-related isoflavones. Total isoflavone content varied greatly among cultivars, from 212 (Black Jet) to 3056 mg/Kg seed (Stressland). Planting time and location affected the isoflavone content. Soybeans planted at Poplar Hill in a double crop system exhibited higher isoflavone concentrations than soybeans planted during the full season at Wye Farm. Plants exposed to low temperatures and precipitation exhibited higher isoflavone content. It may be possible to select cultivars and growing conditions to obtain isoflavone rich seeds.
Effect of Acid Adaptation on the Thermal Inactivation of Listeria monocytogenes in Heating Menstrua Having Various Combinations of pH and Water Activities
(2003-12-15) Edelson-Mammel, Sharon G; Joseph, Sam W; Food Science
The impact of prior growth and food matrix conditions on thermal resistance of L. monocytogenes, a causative agent of the foodborne illness listeriosis, was evaluated in this study. In an initial study ( Main Study #1), acid induced and non-induced cells of thirteen strains of Listeria monocytogenes were placed into two heating menstrua: pH 3.0, water activity (Aw) 0.987 and pH 7.0, Aw 0.970. In twelve out of twenty-six combinations, non-induced cells were more heat resistant than induced cells. L. monocytogenes strain #201, in a follow-up study ( Main Study #2) using a factorial design to test additional combinations of water activity and pH heating menstrua, non-acid-induced cells generally were more heat resistant than acid-induced cells although the acid-induced cells showed greater thermal resistance in the heating menstrua having the lowest pH values. An increase in thermal resistance could lead to underestimation of treatments necessary to eliminate potential contamination by L. monocytogenes.
DETECTION AND CHARACTERIZATION OF ESCHERICHIA COLI O157:H7 AND SALMONELLA IN FOOD
(2004-04-26) CUI, SHENGHUI; MENG, JIANGHONG; Food Science
Escherichia coli O157:H7 and Salmonella are among the most important foodborne pathogens that cause millions cases of infections and hundreds deaths each year in the United States. Beef and poultry products are frequently recognized transmission media for these two organisms. Rapid detection and isolation methods applied to beef or chicken products are expected for these two bacteria. A rapid sample preparation method for E. coli O157:H7 detection by PCR method in ground beef samples was developed by combining different techniques, including filtration, centrifugation, enzyme digestion, and DNA extraction. The detection limit of this method was 103 cells/g without enrichment, and 100 cells/g can be detected after 6 h en-richment. For Salmonella, a poultry specific isolation method was modified from the USDA/FSIS manual by considering the specific characteristics of poultry products. Higher than 95% of the suspect colonies isolated by using the modified method were confirmed as Salmonella by PCR/API 20 E tests. This method was applied on retail organic and conventional chicken samples for Salmonella isolation. All Salmonella isolates were further characterized by serotyping, PFGE and antibiotics susceptibility tests. The results indicated that organic and conventional chicken samples were frequently contaminated with Salmonella, and that Salmonella from organic chicken were more susceptible to antimicrobials commonly used in human and veterinary medicine. High acid resistance capability is another unique characteristic of E. coli O157:H7 which is correlated with low infection dose of this pathogen. Survival mechanism of E. coli O157:H7 cells in gastric juice or acidified LB (pH 2.5) was studied, it was found that the limited availability of glutamate and/or arginine creates an illusion of cell-density-dependent acid sensitive phenotype of E. coli O157:H7 during acid-challenge.
Characterization and Molecular Mechanisms of Antimicrobial Resistance in Foodborne Pathogens
(2004-04-29) Chen, Sheng; Meng, Jianghong; Food Science
The emergence of antimicrobial resistance bacteria in both the medical and agricultural fields has become a serious problem worldwide. The use of antimicrobial agents in animals for prophylaxis and growth promotion favors the selection of antimicrobial resistance in bacteria. These resistant bacteria may subsequently transmit to humans through food chain or human-animal interactions. The objectives of this study were to characterize and determine the molecular mechanisms of antimicrobial resistance in Salmonella and Escherichia coli. E. coli isolates recovered from diseased piglets and chicken in China were characterized for the antimicrobial resistance phenotype and the presence of mutation in their gyrA, gyrB, parC and parE genes. Results indicated that multiple- antimicrobial-resistant E. coli, including fluoroquinolone-resistant variants, are commonly present among diseased swine and chickens in China. DNA sequencing revealed that double gyrA mutations coupled with parC mutation conferred high-level resistance to fluoroquinolones. In addition, Salmonella isolates recovered from retail meats in the United States and China were characterized for antimicrobial resistance genotypes and the horizontal transfer of resistance determinants. The antimicrobial resistance genotypes of Salmonella were consistent to their phenotypes. Genes conferring antimicrobial resistance in Salmonella are often carried on integrons and plasmids, and could be transmitted through conjugation. To rapidly screen for the antimicrobial-resistant and virulence genes from bacteria, a DNA microarray was developed to analyze the antimicrobial resistance and virulence genes from Salmonella and E. coli. Results indicated that microarrray was an effective method to rapidly screen antimicrobial resistance and virulence genes in Salmonella and E coli. Finally, molecular mechanisms of fluoroquinolone resistance, including over-expression of efflux pumps and target gene mutations, were characterized among laboratory-induced and field-acquired fluoroquinolone-resistant Salmonella. The efflux pumps which were overexpressed in resistant strains were deleted and mutated gyrA and parC genes were replaced to determine the contribution of efflux pump and target gene mutations in fluoroquinolone-resistant Salmonella. When Salmonella are exposed to fluoroquinolone, certain efflux pumps are overexpressed in tandem with particular mutations in topoisomerase genes (gyrA and parC). Based on deletion mutagenesis studies, it appears that the most relevant genes with regards to the selection of fluoroquinolone resistance phenotypes among Salmonella are the AcrAB-tolC efflux pump and the gyrA portion of DNA gyrase gene.
Characterization of Listeria monocytogenes Isolated from Retail Organic Chicken
(2004-05-07) Yeh, Emily T.; Meng, Jianghong; Food Science
Listeria monocytogenes is an important foodborne pathogen. It is commonly found in the environment, frequently present in the gut of cattle, poultry, and pigs and can be transmitted to ready-to-eat foods as well as raw meat products. However, no data are available on the prevalence of L. monocytogenes in organic foods. In this study, 210 organic chickens collected from retail stores in the Washington DC area were examined for the presence of Listeria sp. using a modified Food and Drug Administration protocol developed to isolate the organism from meat products. Forty-eight organic chickens were positive for L. monocytogenes. The isolates were serotyped using PCR and subtyped by Pulsed-field gel electrophoresis (PFGE) to determine their genetic relatedness. The data revealed that several Listeria sp. were present on raw retail chicken and L. monocytogenes serotypes associated with human listeriosis were also identified in the product.
GENERIC DIFFERENCES IN ANTIOXIDANT CONCENTRATION IN THE FRUIT TISSUES OF FOUR MAJOR CULTIVARS OF APPLES
(2004-05-21) Kandhari, Pankaj; Quebedeaux, Bruno; Food Science
Apples have been cultivated for over two millennia and over 10,000 named cultivars exist. Antioxidants protect against oxidative stress and provide resistance against superficial scald in apple (Malus domestica Borkh). In the present study four commercially important apple cultivars (Red Delicious, Gala, Fuji and Granny Smith) and source leaves of Gala apple tree were studied. Ascorbate concentration, SOD activity, and protein concentration was determined for Gala leaves and all the four apple (fruit peel and fleshy cortex tissue) cultivars. Gala leaves had the highest ascorbate concentration and SOD activity. Granny Smith fruit peel tissue had the highest and Red Delicious fruit peel tissue had the lowest ascorbate concentration. Granny Smith fruit peel tissue had the highest SOD activity. These results demonstrate that ascorbate concentration and SOD activity in apple tissue may depend on their respective breeding parents, scald susceptibility and the amount of ethylene they produce.
Absorption, Excretion, and Transformation of Individual Anthocyanins in Rats
(2004-08-06) He, Jian; Giusti, Monica M; Magnuson, Bernadene A; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Anthocyanins are polyphenolics responsible for most red to purple colors in plants. Human consumption is increasing because of their potential health benefits and use as natural colorants. However, their absorption and metabolism are not well characterized. We compared anthocyanin absorption and excretion in rats receiving chokeberry, bilberry or grape enriched diet (4g anthocyanin/kg) for 13 weeks. Traces of anthocyanins and metabolites were detected in plasma. In urine, intact anthocyanins and methylated derivatives (~ 24, 8, 15 mg cy-3-gla equivalent/L urine for chokeberry, bilberry, grape) were found. High metabolite concentration suggested accumulation of methylated anthocyanins in tissue. Fecal anthocyanin extraction was maximized with aqueous methanol (60%). Anthocyanin concentration in feces ranged from 0.7 to 2g anthocyanin/kg, similar to cecal content. In the gut, anthocyanin degradation was high for glucosides, moderate for galactosides and negligible for arabinosides and xylosides. Both, glycosylation and acylation seemed to affect the bioavailability of anthocyanins in vivo.
Bioactivity of Ephedra: Integrating Cytotoxicity Assessment with Real-Time Biosensing
(2004-08-12) Fukushima, Kazuko; Lo, Y. Martin; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Ephedrine-type alkaloids (ETA) are major active ingredients of Ephedra, a traditional Chinese medicinal herb used to treat asthma and nasal congestion. Until recently, large amounts of Ephedra were used in dietary supplements for weight loss and athletic performance enhancement. However, indiscriminate consumption of ETA-containing products has resulted in more than 1,000 reported cases of adverse effects. The objective of this study is to evaluate bioactivity of ETA. The toxicities of (-)-ephedrine and (+)-pseudoephedrine were measured using MTT assay on human neuroblastoma (SH-SY5Y) and rat myoblastoma (H9c2 (2-1)), while the stress responses of a panel of biosensing bioluminescent Escherichia coli strains were analyzed. SH-SY5Y showed similar sensitivity to (-)-ephedrine and (+)-pseudoephedrine, while H9c2 (2-1) could differentiate the cytotoxicity of (-)-ephedrine and (+)-pseudoephedrine. The biosensing of the E. coli strains was highly sensitive to the toxicity of ETA and could yield instantaneous response. The RLU ratios dependent on the construct of strains gave unique fingerprintingm pattern of ETA.
Rheological and Textural Characteristics of Copolymerized Hydrocolloidal Solutions Containing Curdlan Gum
(2004-08-12) Sadar, Lisa N; Lo, Y. Martin; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Curdlan, a microbial hydrocolloid, has the ability to form strong, irreversible gels when heated above 80ºC, which distinguishes curdlan from other hydrocolloids. To date, however, very limited information is available on copolymerized solutions containing curdlan gum and other hydrocolloids. The objective was to characterize the rheological and textural behavior of copolymerized hydrocolloidal solutions containing curdlan gum. Hydrocolloidal mixtures containing curdlan were prepared respectively with carrageenan, xanthan, guar, and locust bean gum. Rheological properties under shear and dynamic shear at various concentration ratios were measured using an AR 2000 rheometer. The textural properties were measured using a TA.XT2i Texture Analyzer by Texture Technologies Corp. Synergistic increases in apparent viscosity were observed when curdlan was combined with guar and locust bean gum, which is attributed to the chemical structure. An additive effect was observed in gel strength for all copolymers. Curdlan added to the heat stability of locust bean and guar gum.
THE EFFECTS OF OBESITY ON PLASMA LEVELS OF OMENTIN, A DEPOT-SPECIFIC ADIPOCYTOKINE
(2004-08-27) de Souza Batista, Celia Maria; Kantor, Mark; McLenithan, John; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Obesity is a chronic pathological condition and a risk factor for diabetes and cardiovascular disease. It has been demonstrated that adipose tissue functions not only as a fat storage depot but also as an endocrine organ. Omentin is a protein expressed and secreted in adipose tissue that increases insulin-stimulated glucose transport. To further elucidate omentin's physiological function, its levels were measured by quantitative western blotting in plasma from 44 healthy nondiabetic volunteers (22 women, 22 men). Participants were organized into sibling pairs based on discordant BMI (3-12 Kg/m2). Lean subjects had significantly higher omentin levels than obese/overweight subjects (independent of sex), and significantly higher omentin levels were detected in women compared to men. Omentin levels were inversely correlated with BMI and positively correlated with HDL levels. These data suggest that omentin may play a physiological role in the pathogenesis of obesity-dependent insulin resistance.
DOSE RANGING STUDY OF LUTEIN SUPPLEMENTATION IN ELDERLY WITH AND WITHOUT AGE RELATED MACULAR DEGENERATION
(2004-09-15) Moura, Fabiana Fonseca; Khachik, Frederick; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Age-related macular degeneration (AMD) is the leading cause of blindness among people over the age of 65. Epidemiological studies have indicated that people with a high intake of two dietary carotenoids, lutein and zeaxanthin that accumulate in the human macula, are at a reduced risk of AMD. Possible role of lutein and zeaxanthin in the prevention of AMD has been attributed to their antioxidant function and their ability to act as optical filters. The objectives of this study were to investigate the association between three doses of orally ingested lutein supplements and serum levels of this carotenoid in elderly with and without AMD; to evaluate the possible interaction between supplemental lutein and other dietary carotenoids, retinol, and tocopherol; to correlate the serum levels of lutein with the total macular pigment optical density (MPOD). Forty-five subjects over the age of 60 were divided into 3 groups: subjects without AMD and subjects with middle and end stage of AMD. Subjects in each group were randomized to receive one of the three doses of 2.5, 5, and 10 mg/day of lutein (containing 5% zeaxanthin) for 6 months. Subjects were followed up for 6 months. Carotenoids and their metabolites in the serum of subjects were analyzed by HPLC at weeks 0, 1, 4, 12, 26, 38, and 52. The MPOD of subjects was measured by Heterochromatic Flicker Photometry (HCFP). The data were analyzed using analysis of variance and covariance with repeated measurements (SAS, version 8.2). The mean serum concentrations of lutein in all subjects increased with supplementation. Subjects receiving 10 mg/day of lutein had a 3-4 fold increase in their serum levels of lutein, while those receiving 2.5 and 5 mg/day dose had approximately 2 fold increase. In conclusion, the serum concentration of lutein appears to be dose dependent and the presence or the absence of AMD does not interfere with the serum levels of this carotenoid. Supplemental lutein does not interact with other dietary carotenoids, retinol, and tocopherol. The results from MPOD measurements by HCFP were inconsistent and could not be used to reach any conclusion with regard to MPOD changes.
DETECTION AND CHARACTERIZATION OF HARMFUL ALGAE BY BIOLUMINESCENT STRESS FINGERPRINTING
(2004-11-03) WANG, JING; Lo, Yang-Ming M; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Harmful algal blooms (HABs) pose serious health and economic problems due to biotoxins produced by algae species. A biosensing method employing luminous bacteria was used to detect and characterize the response generated when encountering four critical harmful algae, Karlodinium micrum, Pfiesteria piscicida, Chattonella marina, and Prorocentrum minimum. This sensing system includes six Escherichia coli strains containing different stress-responsive promoters fused to the Photohabdus luminescens luxCDABE reporter. At the concentration of approximatly 6,000 cells/ml, these algal species induced stress responses of the biosensing strains higher than did the control, a non-toxic dinoflagellate Akashiwo sanguinea. The stress responses induced by harmful species showed unique patterns for each of the algae investigated, suggesting that characteristic fingerprints could be generated based on such stress responses. Moreover, dose dependency was observed between the bioluminescence from the sensing strains and the level of algae concentrations, indicating possible quantification of harmful algal species using specific stress response.
Development of Detection and Reduction Methods for Mycotoxins in Corn and Herbal Plant Material
(2005-01-14) D'Ovidio, Kathleen Louise; Bean, George A.; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This is a study of methods to reduce, eliminate or prevent fumonisins and aflatoxins in corn and to survey botanical supplements for aflatoxins. Gamma (Cobalt60) and electron beam irradiation were used to eradicate fumonisin B1. Fumonisin B1 in water was irradiated with 0.5 to 30.0 kGrays. The minimum dosage (0.5 kGray) reduced fumonisin 99%. When naturally contaminated whole and ground corn was exposed to irradiation (10.0-100.0 kGray), Aspergillus and Fusarium fungi were killed; whereas, the level of fumonisins was not changed. Transgenic Bt and non-Bt (NBt) 2000 and 2001 corn were inoculated with Fusarium verticillioides and Aspergillus flavus at silking. At harvest, corn was rated for insect damage, mold populations and levels of fumonisins and aflatoxins. There were little aflatoxins in 2000 corn and none in 2001 corn. Levels of fumonisins in 2000 Bt corn were not significantly lower than the level found in Bt corn; however, 2001 Bt corn showed significantly higher levels of fumonisins than those found in NBt corn. Whereas irradiated herbal material contained no microorganisms, non-irradiated material was contaminated with Aspergillus, Penicillium, and Rhizopus. All A. flavus isolates from herbal material produced aflatoxin B1 on rice cultures. Twenty-four of 25 irradiated and non-irradiated herbals contained AFB1, ranging from trace levels to 450 ng/g. An analytical method to detect aflatoxins in herbal products was developed for ginseng root, Panax quinquefolius. Aflatoxins AFB1, AFB2, AFG1, and AFG2 were added to toxin free ginseng at 2 ng/g, 4 ng/g, 8 ng/g and 16 ng/g. Based on HPLC analysis, mean recoveries ranged from 77% to 92 %. This method was used to survey wild simulated and cultivated ginseng roots harvested after a dry growing season (2002) and a wet growing season (2003). Root samples were from UMD field plots, a commercial source, and from Appalachian growers. Levels of 5.5-32.0 ng/g AB1 were found in 4 samples from a wild simulated grower. One of nine cultivated samples contained trace amounts (0.10 ng/g) AB1 from the 2002 season, and no aflatoxins were found in 2003 samples. In the commercial fresh root sample 16 ng/g of AB1 was found.
Evaluating Knowledge, Attitudes and Behavior Associated with Whole Grain Consumption
(2005-05-03) Simha, Meera; Kantor, Mark A; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Whole grain foods reduce the risk of certain chronic diseases. Americans on an average consume less than one serving per day. We conducted a study to investigate barriers to consuming whole grains and to assess the effectiveness of printed nutrition materials (intervention). A questionnaire was administered to 125 adults before and after a 12-week mail intervention to determine knowledge and changes in attitude and behavior towards whole grain consumption using stages of change model of health behavior. We found a low awareness of whole grain recommendations and an inability to identify whole grains. Cost and availability of whole grain foods were identified as barriers. Post-intervention, there was a significant change in attitude to taste (P=0.0035), cost (P=0.0384), availability (P=0.0218), willingness to buy whole grains (P=0.0343) and willingness to buy a whole grain food that took longer to prepare (0.0082). A significant movement across the stages of change was seen (P<0.0001).
PHYTOCHEMICAL PROFILES AND ANTIOXIDANT PROPERTIES OF WHEAT
(2005-07-28) Zhou, Kequan; Yu, Liangli; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The present study examined and compared wheat grain, bran, aleurone, and micronized aleurone for their antioxidant properties and phytochemical profiles. The results showed that wheat antioxidants were concentrated in bran fraction, particularly in the aleurone layer of wheat bran. Micronized aleurone demonstrated the highest antioxidant activities (scavenging activities against ABTS+, DPPH, ORAC, and chelating activity), and the highest total phenolics and phenolic acids concentration, suggesting that post-harvest treatment may affect the availability of wheat antioxidants. The present +study also investigated bran samples of seven wheat varieties from four different countries for their antioxidant properties and phytochemical profiles. The bran samples exerted enormous differences in concentrations among their phenolic acids, tocopherols and carotenoids. Their antioxidant activities were also notably different from 13% (scavenging capacity against O2-) to 99% (ORAC). These data suggest that wheat varieties and growing conditions might alter wheat antioxidant properties and phytochemical compositions. In addition, eight selected Maryland grown soft wheat varieties or experimental lines were examined for potential beneficial components and antioxidant properties. These soft wheat varieties significantly differed in their ABTS+ scavenging activity and chelating activity. Significant amount of phenolic acids have been demonstrated in all soft wheat grain. But their phenolic acid content markedly differed among different varieties which mainly (89% - 94%) existed as the insoluble bound form with ferulic acid as the predominant phenolic acid. These data suggest the possibility to produce soft wheat varieties rich in selected health beneficial factors for optimum human nutrition through breeding programs. Finally, five phenolic acids commonly present in wheat grain and fractions were examined and compared for their radical scavenging properties and chelating capacities using spectrophotometric and electron spin resonance measurements. These phenolic acids differed in their properties to react with and quench HO, O2-, ABTS+, and DPPH, as well as their capacities to form chelating complexes with transition metals. Strong structure-activity relationships were observed in the present study. Both substitutes on the phenyl ring and the conjugated carbon skeleton may influence the antioxidant properties of these phenolic acids.
CHARACTERIZATION OF OLIVE OILS COMMERCIALLY AVAILABLE IN THE UNITED STATES
(2005-08-15) Ardo, Shane Adam; Yu, Liangli; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This research examined 30 olive oils commercially available in the United States for their fatty acid composition, oxidative stability, and antioxidant capacities. The olive oils in this study differed in their oxidative stability (23.64 - 212.1 h induction time) and concentrations of rancid byproducts (peroxide values: 40.46 - 65.07 umol t-butyl peroxide equivalents/g oil; p-anisidine values: 2.70 - 8.79 OD350/g oil; free fatty acid contents: 0.19 - 1.20 g oleic acid/100 g oil). These commercial olive oils also possessed varying concentrations of total phenolic contents (554 - 810 ug gallic acid equivalents/g oil) and oxygen radical absorbance capacities (1.4 - 11.7 umol Trolox equivalents/g oil) (P < 0.05). These data suggest that olive oils commercially available in the United States differ in their quality, stability, and nutritional value. Furthermore, the retail price may not reflect the quality, stability, and nutritional value of the olive oil.
Detection of norovirus and indicator organisms on fresh produce
(2005-12-06) Williams, Karen Elizabeth; Meng, Jianghong; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Food borne illness is a major problem around the world. Recently, more food borne outbreaks involve produce as the vehicle and viruses as the source of contamination. Norovirus is a common food borne viral pathogen. Genetic diversity among the viruses has made detection difficult. Due to the difficulties in detection, the norovirus is an ideal candidate for having an indicator organism. FRNA bacteriophages share several similarities with enteric viruses and would be an ideal candidate. In this study, we evaluated reverse transcriptase polymerase chain reaction (RT-PCR) detection of norovirus and evaluated using FRNA bacteriophages, E. coli, and Enterococcus as indicator organisms for the virus on produce. Of the five RT-PCR methods tested, only two worked with both controls. Of the 180 produce samples tested, 37.2% were positive for FRNA bacteriophage, 17.2% were positive for Enterococcus, and 0% were positive for E. coli. We conclude that RT-PCR is not an efficient method for screening norovirus on produce and including FRNA bacteriophages as indicator organisms for viruses may help decrease outbreaks.