263 research outputs found

    Numerical and Experimental Studies on the Cutting Energy Requirements of Okra (Abelmoschus esculentus L.)

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    Cutting energy requirements for vegetable crops is a prerequisite in the engineering design of appropriate cost effective cutting systems consuming minimum amount of energy while still providing high quality products. This study attempts the development of predictive equations describing the cutting energy for okra (Abelmoschus esculentus L.). Dimensional analysis based on the Buckingham pi theorem was used to obtain the functional relationship between the cutting energy of the selected vegetable and the independent variables such as tool weight (w), height of tool drop (Hd), tool edge thickness (t), cutting speed (v), crop size (s), crop moisture content (φ), crop contact area (A) and crop density (σ). The developed model was validated with experimental data. A high coefficient of determination of R2 value of 0.973 between the predicted and measured energy values showed that the method is good. Hence the obtained predictive model is appropriate for determining the cutting energy requirements of okra up to 97%

    Numerical and Experimental Studies on the Cutting Energy Requirements of Okra (Abelmoschus esculentus L.)

    Get PDF
    Cutting energy requirements for vegetable crops is a prerequisite in the engineering design of appropriate cost effective cutting systems consuming minimum amount of energy while still providing high quality products. This study attempts the development of predictive equations describing the cutting energy for okra (Abelmoschus esculentus L.). Dimensional analysis based on the Buckingham pi theorem was used to obtain the functional relationship between the cutting energy of the selected vegetable and the independent variables such as tool weight (w), height of tool drop (Hd), tool edge thickness (t), cutting speed (v), crop size (s), crop moisture content (φ), crop contact area (A) and crop density (σ). The developed model was validated with experimental data. A high coefficient of determination of R2 value of 0.973 between the predicted and measured energy values showed that the method is good. Hence the obtained predictive model is appropriate for determining the cutting energy requirements of okra up to 97%

    Agricultural Structures and Mechanization

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    In our globalized world, the need to produce quality and safe food has increased exponentially in recent decades to meet the growing demands of the world population. This expectation is being met by acting at multiple levels, but mainly through the introduction of new technologies in the agricultural and agri-food sectors. In this context, agricultural, livestock, agro-industrial buildings, and agrarian infrastructure are being built on the basis of a sophisticated design that integrates environmental, landscape, and occupational safety, new construction materials, new facilities, and mechanization with state-of-the-art automatic systems, using calculation models and computer programs. It is necessary to promote research and dissemination of results in the field of mechanization and agricultural structures, specifically with regard to farm building and rural landscape, land and water use and environment, power and machinery, information systems and precision farming, processing and post-harvest technology and logistics, energy and non-food production technology, systems engineering and management, and fruit and vegetable cultivation systems. This Special Issue focuses on the role that mechanization and agricultural structures play in the production of high-quality food and continuously over time. For this reason, it publishes highly interdisciplinary quality studies from disparate research fields including agriculture, engineering design, calculation and modeling, landscaping, environmentalism, and even ergonomics and occupational risk prevention

    Freeze-Drying Technology in Foods

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    This Special Issue provides an update on the most recent research and developments in the area of freeze-drying technology in foods. It presents a combination of experimental and modeling studies, offering an overview of oncoming challenges and opportunities on the topic

    Processing and Preservation of Fresh-Cut Fruit and Vegetable Products

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    Fruits and vegetables are plant derived products which can be consumed in its raw form without undergoing processing or conversion. Fresh-cut fruits and vegetables (FFV) are products that have been cleaned, peeled, sliced, cubed or prepared for convenience or ready-to-eat consumption but remains in a living and respiring physiological condition. Methods of preserving FFV to retain its wholesomeness includes washing with hypochlorite, hydrogen peroxide, organic acids, warm water and ozone for disinfestation and sanitization; use of antimicrobial edible films and coatings; and controlled atmosphere storage and modified atmosphere packaging of fruits and vegetables. Exposure of intact or FFV to abiotic stress and some processing methods, induces biosynthesis of phenolic compounds and antioxidant capacity of the produce. Conversely, loss of vitamins and other nutrients has been reported during processing and storage of FFV, hence the need for appropriate processing techniques to retain their nutritional and organoleptic properties. FFV are still faced with the challenge of quality retention and shelf life preservation mostly during transportation and handling, without impacting on the microbiological safety of the product. Hence, food processors are continually investigating processes of retaining the nutritional, organoleptic and shelf stability of FFV

    Alaska's Food (In)Security, Climate Change and the Boreal Forest, Biomass and Hydrocarbons

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    [Geography] -- AMSA: the future of arctic marine shipping: With more shipping traffic in the north and greater marine access due to the retreat of Arctic sea ice, the Arctic states needed to develop a strategy to protect the maritime Arctic, its people, and the environment -- [Forest Sciences] -- Changing the forest and the trees - Is it climate?: Sunspots, sun cycles, El Ninos, La Ninas, atmospheric oscillations, greenhouse gases: climate change has begun to affect the boreal more than any other forest region. / Glenn Patrick Juday -- One Tree in the Tanana Valley: Take one entire tree, and make everything you can out of it-including science and art education. / Nancy Tarnai -- Forest Dynamics & Management: This program monitors the growth and change in Alaska's forests, looking at forest health, characteristics, and regeneration. / Jingjing Liang and Tom Maline -- [High-Latitude Agriculture] -- Alaska's food (in)security: Alaskans have become aware that their food security is precarious - and they're doing something about it. / Deirdre Helfferich and Nancy Tarnai -- Leafhoppers: In Alaska, potato production accounts for 14 percent of total agricultural crop revenues, but the insect pests that can affect them are poorly understood. / Alberto Pantoja, Aaron M. Hagerty, Susan Y. Emmert, and Joseph E. Munyaneza -- You are my Sunshine!: The author took up the challenge: to make a beer brewed with Sunshine Hulless Barley, developed by AFES and released in 2009. / Anita Hartmann -- Reindeer market project makes history: For the first time, reindeer are 4-H project livestock. / George Aguiar -- Security of the red meat supply: Red meat for Alaskans, like other aspects of the food supply in the northernmost state, is dependent upon Outside sources. / Thomas F. Paragi, S. Craig Gerlach, and Alison M. Meadow -- [Natural Resources] -- Salmon and alder: Gasification of Low-Value Biomass in Alaska: Converting Alaska-specific biomass into a volatile hydrocarbon mixture could offset fuel use in remote locations. / Shawn Freitas, Andres Soria, and Cindy Bower -- Unlocking hydrocarbons from biomass: In the world of renewable energy, biomass is the sole source capable of producing hydrocarbons, the raw material needed for fuel, plastics, and the variety of products that maintain the economy. / Andres Soria -- Carex spectabilis: A Sedge for Landscaping and Revegetation in Alaska: Establishing groundcover on barren ground can be a challenge in Alaska; an indigenous sedge may provide a solution. / Jay D. McKendrick -- [People] -- Horace Drury: In Momoriam: This former director of the Alaska Agricultural & Forestry Experiment Station faced the challenge of 'new problems in a new land'. / Nancy Tarnai -- [News & Publications

    Starch retrogradation in tuber : mechanisms and its implications on microstructure and glycaemic features of potatoes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in School of Food and Advanced Technology at Massey University, Palmerston North, Manawatū, New Zealand

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    Figures are re-used under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence, or with the publisher's permission.An increase in the occurrence of diabetes mellitus, cardiovascular disease and obesity in recent years led to the project “Starch retrogradation in tuber: mechanisms and its implications on microstructure and glycaemic features of potatoes”. Potato products can play a role in mitigating these hyperglycaemic events, if starch in these processed products is slowly digested and/or starch-derived glucose is released into the circulation in a slower and more attenuated manner. Three stages were envisaged for the project with an aim to create slowly digestible starch in whole potato tuber (in tuber) through starch retrogradation. Plant-based whole food systems, such as potato tubers encompass different cell compartments, (e.g. cell wall, vacuole, cytoplasm and intracellular spaces) within which starch gelatinisation and retrogradation occur, subject to local interactions of other cell components and water availability. Structural changes of potato starch during retrogradation in tuber and its resulting digestibility were studied. Different water pools in a cooked whole tuber were discerned by the low-field NMR (LF-NMR), having relaxation times T20 at 400 ms. A significant reduction in eGI was observed after cooling and storage compared to freshly cooked tubers. Reheating of retrograded tuber restored some of the susceptibility to enzymatic hydrolysis and internal water mobility. Longer chilled storage (7 days) yet improved the stability of retrograded tuber against reheating effects (at 90 °C). Realignment of the gelatinised amylose and amylopectin changed the distribution of crystalline and amorphous regions during refrigerated storage and subsequent reheating, resulting in starch digestibility varying with treatment combination. Several, but not all, of time-temperature cycle processes were observed to induce stepwise nucleation and propagation, facilitating starch retrogradation in tuber more than did storage fixed at 4 °C. Sous vide processing (at 55 and 65°C), akin to annealing, combined with starch retrogradation in tuber, resulted in potatoes with intermediate eGI (40-72). After reheating at 60°C, the eGI of sous vide cooked-chill potatoes increased moderately, displaying a mixture of partially gelatinised starch and swollen granules. Food processing, i.e. optimum TTC process or sous vide process might facilitate the formation of retrograded starch in tuber, resulting in a reduced eGI (than freshly cooked tubers). To retain the resistance to digestive enzymes in retrograded starch in tuber, reheating at low temperatures (50-60°C) were needed

    NASA-HBCU Space Science and Engineering Research Forum Proceedings

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    The proceedings of the Historically Black Colleges and Universities (HBCU) forum are presented. A wide range of research topics from plant science to space science and related academic areas was covered. The sessions were divided into the following subject areas: Life science; Mathematical modeling, image processing, pattern recognition, and algorithms; Microgravity processing, space utilization and application; Physical science and chemistry; Research and training programs; Space science (astronomy, planetary science, asteroids, moon); Space technology (engineering, structures and systems for application in space); Space technology (physics of materials and systems for space applications); and Technology (materials, techniques, measurements)

    Sustainable Functional Food Processing

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    Functional nutrition is deeply connected with healthy lifestyle and sustainable food production, due to its positive health benefits and the use of economically underexplored and natural raw materials. Expectedly, it appeals to large number of interested consumers while becoming lucrative segment of the food industry with a fast-growing market fueled by new sociodemographic trends. Accordingly, functional juices and beverages made of indigenous fruits are interesting niche for various food market stakeholders. Here, biologically active compounds (BACs) and probiotics that have positive health effects in functional foods (juices) are mostly thermolabile. This is especially important for industry that still employs classical heat treatments (e.g., pasteurization), while being concerned with degradation of food quality in the final products. To prevent this, focus is on designing economic and ecological technologies that are able to preserve nutritional and sensory quality while maintaining microbiological stability in products. Such approaches are based on low-energy consumption and low-impact processing, e.g. “hurdle technology” that combines advanced and conventional methods (e.g., high-power ultrasound, pulse electric field). Food design is another important focus point for consumers’ sensory appeal and economic success of foods. Hence, technologies as 3D food printing can be particularly useful for manufacturing. Based on the above, presented topics are relevant to sustainable functional food production, functional fruit juices, BACs, “hurdle technology,” advanced food processing, 3D food printing, and authentic fruits
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