Search Results

You are looking at 81 - 90 of 454 items for :

  • Refine by Access: All x
Clear All
Free access

Melinda McVey McCluskey

Students are often unable to relate the vegetables and fruits consumed as a snack or part of a meal to the plant parts discussed in botany class. Therefore, an exercise was developed for an introductory horticulture course to increase a student's awareness of botany in everyday life. Fresh produce was brought in from local gardens, grocery stores, or farmers markets. Vegetables and fruits were selected that are consumed for their roots, stems, leaves, flower, fruit, and seeds. As each vegetable or fruit was introduced, students named the plant and plant part. As each part was identified it was “dissected” to show the taxonomic features. The different fruit types, i.e., berry, hesperidium, pepo, drupe, and pome were explained. Students were encouraged to taste all vegetables and fruits as they were prepared. Most students sampled the produce as it was passed around the group. Students easily recognized much of the produce, i.e., carrots, asparagus, tomatoes, peas, oranges, and broccoli. The second part of the exercise exposed students to vegetables and fruits that were unfamiliar. Most of the students had little exposure to the more exotic fruits and vegetables that are now available. New vegetables and fruits that students said they would add to their diet include jicama, pomegranate, and star fruit.

Free access

Gray R. Bachman

The horticulture industry continues to show interest in using stabilized organic wastes as a component of container media. Vermicompost, also known as worm-worked waste or worm castings, is one of these materials of interest and can be produced from a number of organic wastes, including manure wastes. One issue that has not been addressed is the uniformity of vermicomposts produced from wastes of different sources. Are all vermicomposts created equal? The uniformity of vermicompost is important for growers to consider when using as a medium amendment. This research project investigated the physical properties of vermicompost 1) from different sources of wastes and 2) from a single waste source sequentially sampled over time. The first stage determined the physical properties of vermicompost from beef manure, hog manure, and peat-based media used by two earthworm growers. There were significant differences between the four vermicomposts in bulk density, air volume, percent air volume, percent volumetric moisture, total porosity, and water holding capacity. The second stage involved determining the physical characteristics of vermicompost produced from beef manure collected at the Illinois State University Research Farm from cattle receiving a consistent diet through the year. Manure was collected bimonthly. There was no difference in vermicompost bulk density among the samples. There were significant differences in air volume, percent air volume, percent volumetric moisture, total porosity, and water holding capacity. These changes in vermicompost physical characteristics must be quantified for growers to accurately predict performance as a growth medium amendment.

Free access

Mark G. Lefsrud and Dean A. Kopsell

Plant growing systems have consistently utilized the standard Earth day as the radiation cycle for plant growth. However, the radiation cycle can easily be controlled by using automated systems to regulate the exact amount of time plants are exposed to irradiation (and darkness). This experiment investigated the influence of different radiation cycles on plant growth, chlorophyll and carotenoid pigment accumulation in kale (Brassica oleracea L. var. acephala D.C). Kale plants were grown in growth chambers in nutrient solution culture under radiation cycle treatments of 2, 12, 24, and 48 h, with 50% irradiance and 50% darkness during each time period. Total irradiation throughout the experiment was the same for each treatment. Radiation cycle treatments significantly affected kale fresh mass, dry mass, chlorophyll a and b, lutein, and beta-carotene. Maximum fresh mass occurred under the 2-h radiation cycle treatment. The maximum dry mass occurred under the 12-h radiation cycle treatment, which coincided with the maximum accumulation of lutein, beta-carotene, and chlorophyll a, expressed on a fresh mass basis. The minimum fresh mass occurred during the 24 h radiation cycle treatment, which coincided with the largest chlorophyll b accumulation. Increased levels of chlorophyll, lutein and beta-carotene were not required to achieve maximum fresh mass production. Environmental manipulation of carotenoid production in kale is possible. Increases in carotenoid concentrations would be expected to increase their nutritional contribution to the diet.

Free access

Ji Tian, Zhen-yun Han, Li-ru Zhang, Ting-Ting Song, Jie Zhang, Jin-Yan Li, and Yuncong Yao

Anthocyanins are protective pigments that accumulate in plant organs such as fruits and leaves, and are nutritionally valuable components of the human diet. There is thus considerable interest in the factors that regulate synthesis. Malus crabapple leaves are rich sources of these compounds, and in this study we analyzed leaf coloration, anthocyanin levels, and the expression levels of anthocyanin biosynthetic and regulatory genes in three crabapple cultivars (Royalty, Prairifire, and Flame) following various temperature treatments. We found that low temperatures (LTs) promoted anthocyanin accumulation in ‘Royalty’ and ‘Prairifire’, leading to red leaves, but not in ‘Flame’, which accumulated abundant colorless flavonols and retained green colored leaves. Quantitative reverse transcript PCR (RT-PCR) analyses indicated that the expression of several anthocyanin biosynthetic genes was induced by LTs, as were members of the R2R3-MYB, basic helix–loop–helix (bHLH) and WD40 transcription factor families that are thought to act in a complex. We propose that anthocyanin biosynthesis is differentially regulated in the three cultivars by LTs via the expression of members of this anthocyanin regulatory complex.

Free access

Prem Nath

The world produces adequate food for everyone, but unequal distribution has created a gap between the countries that produce more food than they consume and those countries with deficit production. About 815 million people suffer from hunger and malnutrition, mostly in the developing world. By 2020, the developing world is expected to face the overwhelming challenge of a 97.5% increase in population; moreover, developing countries will face serious challenges with the trend of a major shift in population from rural to urban areas, where 52% of the people will live in megacities—all asking for more food, land, and infrastructure. According to the World Health Organization, an estimated 334 million children in developing countries are malnourished. In 2020, one out of every four children in these countries will still be malnourished. It is recognized that modern agriculture must diversify production and achieve sustainable higher output to supplement food security. In order to reduce pressure on cereals as well as to improve human nutrition through the consumption of other nutritious crops, diversification in cropping patterns can provide better options. The increased production and consumption of fruits and vegetables, with their wide adaptation and providers of important nutrients (especially vitamins and minerals), offer promise for the future. Fruits and vegetables as food and diet supplements are gaining momentum in most countries. In addition, recent experimental evidence has shown the growing importance of fruits and vegetables in the prevention of noncommunicable diseases. Further, horticulture would play an important role in urban and peri-urban agriculture and development.

Free access

Dean A. Kopsell, Scott McElroy, Carl Sams, and David Kopsell

Vegetable crops can be significant sources of nutritionally important dietary carotenoids and Brassica vegetables are sources that also exhibit antioxidant and anticarcinogenic activity. The family Brassicaceae contains a diverse group of plant species commercially important in many parts of the world. The six economically important Brassica species are closely related genetically. Three diploid species (B. nigra, B. rapa, and B. oleracea) are the natural progenitors of the allotetraploid species (B. juncea, B. napus, and B. carinata). The objective of this study was to characterize the accumulation of important dietary carotenoid pigments among the genetically related Brassica species. The HPLC quantification revealed significant differences in carotenoid and chlorophyll pigment accumulation among the Brassica species. Brassica nigra accumulated the highest concentrations of lutein, 5,6-epoxy lutein, violaxanthin, and neoxanthin. The highest concentrations of beta-carotene and total chlorophyll were found in B. juncea. Brassica rapa accumulated the highest concentrations of zeaxanthin and antheraxanthin. For each of the pigments analyzed, the diploid Brassica species accumulated higher concentrations, on average, than the amphidiploid species. Brassicas convey unique health attributes when consumed in the diet. Identification of genetic relationships among the Brassica species would be beneficial information for improvement programs designed to increase carotenoid values.

Free access

Kyoung-Shim Cho, Hyun-Ju Kim, Jae-Ho Lee, Jung-Hoon Kang, and Young-Sang Lee

Fatty acid is known as a physiologically active compound, and its composition in rice may affect human health in countries where rice is the major diet. The fatty acid composition in brown rice of 120 Korean native cultivars was determined by one-step extraction/methylation method and GC. The average composition of 9 detectable fatty acids in tested rice cultivars were as followings: myristic acid; 0.6%, palmitic acid; 21.2%, stearic acid; 1.8%, oleic acid; 36.5%, linoleic acid; 36.3%, linolenic acid; 1.7%, arachidic acid; 0.5%, behenic acid; 0.4%, and lignoceric acid; 0.9%. Major fatty acids were palmitic, oleic and linoleic acid, which composed around 94%. The rice cultivar with the highest linolenic acid was cv. Jonajo (2.1%), and cvs. Pochoenjangmebye and Sandudo showed the highest composition of palmitic (23.4%) and oleic acid (44.8%), respectively. Cultivar Pochuenjangmebye exhitibed the highest composition of saturated fatty acid (28.1%), while cvs. Sandudo and Modo showed the highest mono-unsaturated (44.8%) and poly-unsaturated (42.4%) fatty acid composition, respectively. The oleic acid showed negative correlation with palmitic and linoleic acid, while positive correlation between behenic and lignoceric acids was observed.

Free access

Jennifer L. Waters and Stephen R. King

Carotenoids are important phytochemical components of our diet and have gained recent attention as important nutritive compounds found mainly in fruits and vegetables with red, orange, and yellow hues. Lycopene is often cited as being inversely correlated with the occurrence of various cancers, in lowering rates of cardiovascular disease, and improving other various other immune responses. Antioxidant activity, specifically oxidative radical quenching power, is the putative rationale for carotenoids' involvement in disease risk reduction. It is unlikely, however, that carotenoid content and antioxidant capacity are directly correlated in the whole food since there are other antioxidants present in watermelon, such as various free amino acids. A total measure of antioxidant potential may prove to be a useful tool for measuring watermelon nutritional value and implementing pursuant breeding goals. One assay that has gained recent popularity is the oxygen radical absorbance capacity (ORAC) assay. ORAC includes two assays that separate lipophylic and hydrophilic antioxidants. Currently, most ORAC protocols use isolated compounds or freeze-dried fruit or vegetable samples. Here, the application of a standard hexane-type extraction method, which is more amenable to whole food carotenoid-containing samples, was investigated as a candidate extraction method for the ORAC assay. Variants of this method as well as of the standard ORAC extraction were compared for extraction efficiency. Finally, ORAC values were correlated with carotenoid content and shown to hold a loose negative correlation. Possible reasons for this are considered and discussed.

Free access

Joseph K. Peterson, Howard F. Harrison, D. Michael Jackson, and Maurice E. Snook

Periderm and cortex tissues of 14 genetically diverse sweetpotato [Ipomoea batatas (L.) Lam.] clones were grown under low stress conditions and analyzed for their content of scopoletin ((7-hydroxy-6-methoxycoumarin) and scopolin (7-glucosylscopoletin). A wide range of concentrations of both compounds was found in both tissues. The two compounds were tested in vitro for their biological activity (concentration-activity relationships) using several bio assays: germination of proso-millet (Panicum milliaceum L.) seed; mycelial growth of the sweetpotato fungal pathogens Fusarium oxysporum Schlecht. f. sp. batatas (Wollenw.) Snyd. & Hans, F. solani (Sacc.) Mart., Lasiodiplodia theobromae (Pat.) Griffon & Maubl., and Rhizopus stolonifer (Ehr. ex Fr.) Lind; and growth and mortality of diamondback moth[Plutella xylostella (L.)] larvae on artificial diet. The glycoside scopolin showed little activity, except moderate inhibition of F. oxysporum. The aglycone scopoletin inhibited seed germination and larval growth; however, at much higher concentrations than were measured in the tissues. Mycelial growth of the four pathogenic fungi, however, was inhibited at concentrations occurring in some sweetpotato clones.

Free access

Judith A. Abbott*

Demand for fresh fruits and vegetables is increasing worldwide in response to health concerns, wealth, and the desire for variety in the diet. However, consumption of produce is contingent on the ability of the industry to provide high quality fresh produce and on its convenience, as well as on consumer education and economics. Texture measurement is accepted by horticultural industries as a critical indicator of quality of fruits and vegetables. The fresh produce industry and, indirectly, consumers need methods for measuring produce texture to ensure the quality within a grade, and scientists need measurements to quantify the results of their treatments, whether treatments are genetic, chemical, or physical. The variety of attributes required to fully describe textural properties can only be fully measured by sensory evaluation by a panel of trained assessors. However, instrumental measurements are preferred over sensory evaluations for both commercial and research applications because instruments are more convenient, less expensive, and tend to provide consistent values when used by different people. Thus, instrumental measurements need to be developed that predict sensory evaluations of texture. Such instrumental measurements can then provide a common language among researchers, producers, packers, regulatory agencies, and customers. We compare sensory evaluations of specific critical textural attributes to instrumental force/deformation measurements on a wide variety of fruits and vegetables with relatively uniform bulk tissues, such as apples, bananas, carrots, jicama, melons, pears, potatoes, rutabagas, and several others.