Processing Cassava for Animal Feeds

Total Page:16

File Type:pdf, Size:1020Kb

Processing Cassava for Animal Feeds Table of Contents Preface Acknowledgments I. Introduction II. Utilization of cassava Cassava in African farming and food systems: Implications for use in livestock feeds Cassava in food crop and livestock production systems Cassava in food systems during crisis Importance of cassava in future food systems Implications for cassava use in livestock feed Conclusion An overview of traditional processing and utilization of cassava in Africa Why cassava needs processing Constraints in the traditional processing of cassava Traditional methods for processing cassava Processing techniques and reduction of cyanide in cassava Processed products Processing equipment Storage of processed products Cassava leaves as vegetable Utilization of processed products Modes of consumption Potentials of cassava as animal feed The future of cassava References Utilization of cassava in nonruminant livestock feeds Agronomic and nutritional potentials of cassava Utilization of cassava in poultry feeding Utilization of cassava in swine feeding Future perspective References A review of ruminant responses to cassava-based diets Response of ruminants fed on cassava and its by-products Nutrient content of cassava Utilization of cassava products and by-products by ruminants By-products of cassava tuberous root processing Constraints to widespread utilization of cassava products Future research needs References Effect of protein deficiency on utilization cassava peel by growing pigs Materials and methods Results Discussion References The use of cassava feeding rabbits Cassava root meal Cassava peel meal Cassava leaf meal Effect of processing on feeding value of cassava References The potential of cassava peel for feeding goats in Nigeria Materials and methods Results and discussion References III. Varietal improvement of cassava Cassava varietal improvement for processing and utilization in livestock feeds Quantitative biology of cassava varieties suitable for livestock feeds Biochemical aspects of cassava utilization for livestock Low cyanide cassava varieties References The adoption of improved cassava varieties and their potential as livestock feeds in southwestern Nigeria Cassava varieties in southwestern Nigeria Level of adoption of improved cassava varieties in southwestern Nigeria The sociology of cassava adoption and spread Cassava as a livestock feed resource The economies of cassava as a livestock feed resource References IV. Processing of cassava Processing cassava for animal feeds Processing of cassava into chips and pellets Artificial dryers Processing of cassava leaves and stems Production of single cell protein from cassava References Constraints and projections for processing and utilization of Cassava Mechanized processes of cassava detoxification Utilization of detoxified cassava in poultry feeds Projections Constraints References V. Cassava utilization in selected countries The use of cassava broiler diets in Côte d'Ivoire: Effects on growth performance and feed costs Materials and methods Results and discussion Acknowledgment References Evaluation of cassava energy source in dairy cow concentrate feeds in Kenya Materials and methods Results Discussion References Processing and utilization of cassava livestock feed in Tanzania Cassava production in Tanzania Cassava processing in Tanzania Cassava-based diets for pigs Cassava-based diets for poultry Cassava a feed source for ruminants Present and potential roles of cassava as a livestock feed Why cassava is not widely used for livestock feeding Conclusion References Cassava production and utilization in Liberia Production and processing Research Cassava as animal feed References VI. Reports of working groups and workshop recommendations Reports of working groups Report of working group A Report of working group B Report of working group C Workshop summary and recommendations Summary of workshop Recommendations List of participants Cassava in African farming and food systems: Implications for use in livestock feeds Cassava in food crop and livestock production systems Cassava in food systems during crisis Importance of cassava in future food systems Implications for cassava use in livestock feed Conclusion F.I. Nweke and H.C. Ezumah Farming systems can be broadly defined to include the food system as a subset in the overall context of production of food and shelter materials. The food system may also be defined to include crop and livestock production systems as a subset when it is considered as a continuum of activities starting from production through processing and distribution to utilization of crop and livestock products for food. The importance of the latter definition is underscored by the decision, in 1987, to award the first General Foods World Food Prize, as follows: The concept of the total food chain lies at the heart of the General Foods World Food Prize, for each link in that chain plays a vital role. Every aspect of the production, processing and distribution of food needs to be considered, including farming, the agricultural sciences, food sciences and technology, nutrition, economics, technology transfer, governmental policies, transportation and distribution and education [General Foods 1987]. The General Foods' definition is adopted in this paper and livestock production systems as subsets of food systems. This paper will describe the role of cassava in the food crop product/on systems of tropical Africa. We will also explore the degree to which tropical African countries can meet their cassava needs for human consumption and generate a surplus for use in livestock feeds. In collaboration with international Center for Tropical Agriculture (CIAT), Colombia, the Overseas Development Natural Resources Institute (ODNRI), and national agricultural research systems (NARS) in Africa, IITA has embarked on a continent-wide survey of cassava in Africa. The survey is called the Collaborative Study of Cassava in Africa (COSCA) and it is initially concentrated in six countries namely, Côte d'Ivoire, Ghana, Nigeria, Tanzania, Uganda, and Zaire, selected partly on the basis of the importance of cassava in the farming and food systems of the countries. The survey data were analyzed on the basis of production projections using time series data provided by USDA as well as other secondary data. Cassava in food crop and livestock production systems The interrelationships between crop-based production systems and livestock-based systems are illustrated in figure l, which shows a complex eastern Nigeria system, in which the family household is the major source of labor used for food crop and livestock production. Figure 1: Interaction of crop and animal farming In a cassava-based system (adapted from Lagemann 1977) In this food crop system, cassava is commonly intercropped with early maturing annuals such as maize, and vegetables like okro, egusi and bitter leaf. The crops intercropped with cassava in different parts of Africa very with regions of growth and food preferences. In Zaire, the intercrop may be dominated by grain legumes such as groundnuts and phaseolus beans, while in Sierra Leone, The Gambia, Liberia, and Guinea, rice is the dominant intercrop. Protected trees like Parkia , and nonwoody perennials such as plantains and bananas, are also frequently grown in patches or as individual stands in cassava fields. While cassava and associated crops are the main food crops, trees provide fuelwood and construction materials. Dry cassava peels are fed to goats and sheep, and pigs eat the tubers. In some countries, cassava leaves are consumed by humans and also fed to animals, or used as poultry rations. These animals provide the household with eggs and meat for consumption and the market. Animal wastes are incorporated with household refuse as mulch and used for soil enrichment or are carted directly into herds, especially those close to homes. Some existing cassava cropping patterns modified to incorporate only two crops are illustrated in figure 2. Pattern 2 is common in Zaire and some countries in West Africa while pattern 4 is dominant in West Africa. Subsidiary crops associated with these patterns may be fruits and leafy vegetables. Patterns 1 and 3 are further modifications of the traditional, complex crop mixture systems to nearly monocrop pattern (1) and a completely monocrop pattern (3). Soybean may be intercropped with cassava as in patterns 1, 2 or 4. Cassava is highly compatible as an intercrop with these annuals because of its slow initial growth, especially between planting and six to eight weeks of growth. The annuals which grow faster during the initial growth phases rarely compete adversely with cassava and have been shown to smother weeds. The advantage of soybeans, a relatively new crop in cassava growing areas of Africa, is that it will supply the deficient protein component to a predominantly cassava diet in both human food and animal feeds. Figure 2: Cassava cropping patterns and alternative patterns for humid southern Nigeria Cassava in food systems during crisis The role of cassava in food systems will depend on what happens to real income. Cassava is a crisis crop. In times of war, drought or low national incomes, cassava consumption increases relative to alternative food staples such as yam, maize, rice, and wheat. Cassava in certain forms is a low income consumers' staple. Although an individual may not increase the quantity of cassava consumed in a year, as national income declines, annual average cassava consumption per person increases because more people begin
Recommended publications
  • Potato Wastewater Treatment
    6 Potato Wastewater Treatment Yung-Tse Hung and Howard H. Lo Cleveland State University, Cleveland, Ohio, U.S.A. Adel Awad and Hana Salman Tishreen University, Lattakia, Syria 6.1 INTRODUCTION In the past two decades, the potato industry has experienced rapid growth worldwide, accom- panied by a staggering increase in the amount of water produced. It is estimated that the US potato industry alone generates about 1.3 Â 109 kg of wastes each year [1]. Large volumes of wastewater and organic wastes are generated in potato processing as result of the water used in washing, peeling, and additional processing operations. The potato industry is well known for the vast quantities of organic wastes it generates. Treatment of industrial effluents to remove organic materials, however, often changes many other harmful waste characteristics. Proper treatment of potato processing wastewaters is neces- sary to minimize their undesirable impact on the environment. Currently, there is an increasing demand for quality improvement of water resources in parallel with the demand for better finished products. These requirements have obliged the potato industry to develop methods for providing effective removal of settleable and dissolved solids from potato processing wastewater, in order to meet national water quality limits. In addition, improvement and research have been devoted to the reduction of wastes and utilization of recovered wastes as byproducts. This chapter discusses (a) the various potato processing types and steps including their sources of wastewaters; (b) characteristics of these wastewaters; (c) treatment methods in detail with relevant case studies and some design examples; and (d) byproduct usage.
    [Show full text]
  • Identification of Valuable Corn Quality Traits for Starch Production
    Identification of Valuable Corn Quality Traits for Starch Production By: Lawrence A. Johnson Center for Crops Utilization Research Food Science and Human Nutrition C. Phillip Baumel Economics Connie L. Hardy Center for Crops Utilization Research Pamela J. White Food Science and Human Nutrition A project of the Iowa Grain Quality Initiative Traits Task Team Funded by the Iowa Corn Promotion Board 306 West Towers 1200 35th St. West Des Moines, IA 50266 October 1999 Center for Crops Utilization Research Iowa Agriculture & Home Economics Experiment Station Iowa State University, Ames, IA 2 Acknowledgment This report is intended to provoke discussion and debate that will lead to a vision among researchers in public institutions, seed companies, and the starch processing and food industries for modifying corn traits for starch (and other complex carbohydrates) production to enhance utilization and profitability of growing corn. The report attempts to provide direction to farmer organizations and to the corn industry about potential targets for investing research funds. One should recognize that some of the modifications considered required speculation about functional properties and potential applications. Additional research on the relationship between the structures of starch and other complex carbohydrates and functionality in food and industrial applications may refute some of that speculation. Also, this document is a consensus report taking into account the recommendations and reviews of the consultants and advisors identified below. Dr. Jay-lin Jane, Food Science and Human Nutrition, Iowa State University, Ames, IA Dr. Morton W. Rutenberg, Emmar Consultants, North Plainfield, NJ Dr. Henry Zobel, ABCV Starch, Darien, IL Dr. Robert Friedman, Cerestar USA, Inc., Hammond, IN Dr.
    [Show full text]
  • Water Minimization in the Tapioca Starch Production Industry: a Decision Support System
    The 3rd Conference on Starch Technology O-STARCH-03 Water Minimization in the Tapioca Starch Production Industry: A Decision Support System Natthakan Rungraeng1, Kanchana Saengchan1, Annop Nopharatana2 and Warinthorn Songkasiri3 1Department of Food Engineering, Faculty of Engineering, Food Engineering Practice School, King Mongkut’s University of Technology Thonburi, Ratchburana, Bangkok 10140, Thailand 2Pilot Plant Development and Training Institute (PDTI), King Mongkut’s University of Technology Thonburi, Bangkhuntien, Bangkok 10150, Thailand 3Biochemical Engineering and Pilot Plant Research and Development Unit (BEC), National Center for Genetic Engineering and Biotechnology (BIOTEC), 83 Moo 8 Thakham, Bangkhuntien, Bangkok, 10150, Thailand Abstract A typical tapioca starch manufacturing process consumes freshwater approximately 10 to 30 m3 per ton of starch produced. The amount of water consumption can be reduced considerably by the recycle of wastewater. This research utilizes a water pinch technology as a tool to minimize water consumption in the starch production process. The water pinch decision support system, called the W-Pinch program, was generated by the Starch Engineering and Process Optimization (SEPO) Program, King Mongkut’s University of Technology Thonburi (KMUTT). The W-Pinch modelling system includes 7 composition balances of water, starch, protein, pulp, sand, peel, and sulfur. Water composition is correlated to freshwater and wastewater calculations and the moisture content of the product. Starch and pulp compositions demonstrate the extractor efficiency. Peel, sand, protein, and sulfur compositions are the control parameters to monitor and control the final product quality after applying the water recycling patterns. Each composition stream was balanced for each unit in the starch production process, i.e., root receiver, washer/cutter, rasper/grinder, coarse extractor, fine extractor, separator I, separator II, separator III, centrifugal dewater unit, and flash dryer.
    [Show full text]
  • Wheat - a Challenging Substrate for Starch Production
    ŻYWNOŚĆ 2(23) Supl., 2000 W. BERGTHALLER, H.-J. KERSTING WHEAT - A CHALLENGING SUBSTRATE FOR STARCH PRODUCTION Abstract In contrast to the world-wide given situation for maize as the main substrate in starch isolation, wheat gains an advantageous position in the European starch industry although technical starch yield cannot compete fully material prices. Its remarkable position profits also from wheat gluten as valuable by­ product. Further indication for rising preference can be seen in the installation of new processing capaci­ ties in Europe. However, the economic situation of wheat starch production follows unavoidable fluctua­ tions of wheat gluten markets. Political decisions play an important role, too. The challenging situation connected with wheat as substrate for starch extraction is result of develop­ ments in equipment and remodelling of technology. The most important contribution consisted in an obvious shift of the relation of water to flour used for flour/water mixture preparation, starch and gluten extraction, and refining. This was initialised mainly by the introduction of separation techniques using centrifugal principles. With respect to limited availability of water and increasing costs for waste water treatment reduction of water supply is a steady target. In close connection to developments in separation technology wheat and wheat flour should gain ex­ tended attraction. Published standards are limited and reveal at most characteristics oriented to the, Martin process. With respect to recent developments in technology, alternative testing procedures have been proposed. Results demonstrate the suitability and specificity of the „Mixer method", a procedure adapted to flour/water relations in centrifugal separation. But, the time consuming procedure restricts general application.
    [Show full text]
  • Physicochemical and Functional Properties of Wheat Starch in Various Foods
    SPECIAL SECTION: Molecular Diversity and Health Benefits of Carbohydrates from Cereals and Pulses Understanding the Physicochemical and Functional Properties of Wheat Starch in Various Foods Clodualdo C. Maningat1 and Paul A. Seib2,3 ABSTRACT Cereal Chem. 87(4):305–314 This report highlights the structure and myriad properties of wheat eating quality, and texture of pasta and noodles, and its role is more than a starch in various food systems. Granule shape, size, and color, plus the filler in yeast-leavened bread products. Recent developments in the prop- proportion of A- and B-granules, amylose content, and molecular struc- erties and applications of commercially important wheat pyrodextrins and ture largely determine its functionality in food. The role of wheat starch is RS4-type resistant wheat starches are reported, along with their use to portrayed in three categories of flour-based foods that differ in water produce fiber-fortified foods. Gluten-free foods are also discussed. content. Wheat starch influences the appearance, cooking characteristics, Wheat (Triticum aestivum L.) is unique because of the proper- synthase I. Other embedded proteins with enzyme activities are ties of two principal macromolecular components, protein (gluten) soluble starch synthase, starch branching enzyme, and two poly- and starch. Wheat gluten is responsible for the dough-forming peptides that may have starch synthase activities (Rahman et al ability of wheat flour to make bread, which is unmatched by any 1995; Gao and Chibbar 2000). other proteins of plant, animal, or microbial origin (Gianibelli et The lipids consist of 0.7–1.4% that is interior-bound (Morrison al 2001; Wrigley et al 2006).
    [Show full text]
  • Starch and Starch Sugar Wastewater Treatment Technology Scheme and Operation Monitoring
    id27306828 pdfMachine by Broadgun Software - a great PDF writer! - a great PDF creator! - http://www.pdfmachine.com http://www.broadgun.com [Type text] ISSN : [0T9y7p4e -t e7x4t3] 5 Volume 1[0T Iyspseu ete 1x9t] BioTechnology 2014 An Indian Journal FULL PAPER BTAIJ, 10(19), 2014 [11286-11290] Starch and starch sugar wastewater treatment technology scheme and operation monitoring Chen Yong1*, Liu Shuaixia1, Xin Yinping2 1Henan Institute of Engineering,No.1 Xianhe Road, Longhu Xinzheng, Zhengzhou, Henan Province, 45119, (CHINA) 2Henan Zhengda environmental technology consulting engineering company limited, Wenhua Road No. 56, Zhengzhou City, Henan Province,450002, (CHINA) E-mail : [email protected] ABSTRACT This paper mainly through wastewater renovation project of a program of starch and starch sugar production enterprises and its actual operating results, the analysis of various treatment structures combined operation of the treatment plant treatment effect, the purpose is to understand the characteristics of each treatment structures in starch and starch sugar wastewater treatment process, for the follow-up design or improvement of starch and starch sugar the wastewater treatment technology has certain reference significance. KEYWORDS Starch and starch sugar; Wastewater treatment renovation; Monitoring results. © Trade Science Inc. BTAIJ, 10(19) 2014 Chen Yong 11287 INTRODUCTION Starch is polyhydroxylated natural high molecular compound, widely exists in plant roots, stems and fruits, food, medicine, chemical, papermaking, textile and other industrial sectors of the main raw material. The main raw material crop starch production is the corn, potato and wheat. Produce a lot of high concentrations of acidic organic wastewater in starch processing process, its content with the production fluctuation and change from time to time, which is mainly soluble starch and a small amount of protein, no general toxicity.
    [Show full text]
  • Aspects of Agricultural Use of Potato Starch Waste Water
    Reprint Neth. J. agric. Sei. 21(1973): 85-94 Aspects of agricultural use of potato starch waste water F. A. M. de Haan1, G. J. Hoogeveen2 and F. Riem Vis3 1 Laboratory of Soils and Fertilizers, Agricultural University, and Institute for Land and / Water Management Research, Wageningen, the Netherlands 2 Government Service for Land and Water Use, Utrecht, the Netherlands 3 Institute for Soil Fertility, Haren, the Netherlands Accepted: 24 January 1973 Summary Agricultural industries in the northeastern part of the Netherlands, with the potato starch industry as the most important one, produce a very large amount of waste water. Research work is now performed on possible solutions to the environmental problems resulting from discharge of this water on open canals. Land disposal offers such a possibility. Since the waste water contains the natural components of potatoes only it can be considered as a relatively innocent type of industrial waste water. Moreover, the main constituents are also the major elements for plant nutrition thus rendering an opportunity to recycle these components. Evaluation ofwast ewate r utilization for agricultural purposesmus t bebase d on a number of criteria of whichth emos t important onesare :purificatio n byth esoi lsystem , fertilization of agricultural crops, and economic effects for the farmer whose land is used for this kind of waste water treatment. In the economic evaluation with respect to other proposed solutions, cost of application is also to be taken into account. This article is confined to the three first-mentioned criteria. Experimental results and model calculations indicate that with mean yearly application rates in the range of 50 to 100 mm the relevant requirements can be met at a farmers profit of about 100 guilders per ha.
    [Show full text]
  • Status of Starch Sources in India, Their Processing and Utilization
    Status of Starch Sources in India, their Processing and Utilization Dharmesh Chandra Saxena Department of Food Engineering & Technology SANT LONGOWAL INSTITUTE OF ENGINEERING & TECHNOLOGY LONGOWAL (PUNJAB) INDIA 1 !! Starch,Starch, αα--DD glucanglucan polymerpolymer -- aa majormajor energyenergy sourcesource inin mostmost dietdiet !! VersatilityVersatility andand heterogeneityheterogeneity ofof applicationapplication inin thethe foodfood industryindustry !! TheThe useuse ofof starchstarch productsproducts asas aa foodfood ingredientingredient isis usuallyusually notnot basedbased onon theirtheir nutritionalnutritional valuevalue butbut onon theirtheir functionalfunctional value.value. !! AlmostAlmost allall majormajor industriesindustries (food(food andand nonnon--food)food) havehave foundfound somesome applicationsapplications forfor starch.starch. 2 StarchStarch isis widelywidely foundfound inin !! cerealcereal graingrain seedsseeds (e.g.(e.g. corn,corn, rice,rice, wheat),wheat), !! tuberstubers (e.g.(e.g. potato),potato), !! rootsroots (e.g.(e.g. sweetpotato,sweetpotato, cassava,cassava, arrowroot),arrowroot), !! legumelegume seedsseeds (e.g.(e.g. peas,peas, beans),beans), !! fruitsfruits (e.g.(e.g. greengreen bananas,bananas, unripeunripe apples),apples), andand !! leavesleaves (e.g.(e.g. tobacco).tobacco). 3 ! Starch can be simply manufactured by the combination of grinding the starch-rich crop followed by wet separation techniques. ! The starch granules will sediment in water due to their higher density. ! Three main classes of starch
    [Show full text]
  • Cassava As Animal Feed in Ghana: Past, Present and Future
    CASSAVA AS ANIMAL FEED IN GHANA: PAST, PRESENT AND FUTURE i CASSAVA AS ANIMAL FEED IN GHANA: PAST, PRESENT AND FUTURE Author Kwame Oppong-Apane - Chief Executive Officer, Oporhu Agricultural and Rural Development Consultancy Limited, P.O. Box CT 1738, Cantonments, Accra, Ghana Editors Berhanu Bedane Cheikh Ly Harinder P.S. Makkar Animal Production and Health Animal Production and Health Animal Production Officer, Officer, FAO Sub-regional Officer, FAO Regional Office Livestock Production Systems office for West Africa (SFW), for Africa (RAF), Accra, Ghana Branch (AGAS), FAO, Rome, Accra, Ghana Italy Food and Agriculture Organization of the United Nations Accra, 2013 i The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by FAO in preference to others of a similar nature that are not mentioned. The views expressed in this information product are those of the author(s) and do not necessarily reflect the views or policies of FAO. ISBN 978-92-5-107687-3 (print) E-ISBN 978-92-5-107688-0 (PDF) © FAO 2013 FAO encourages the use, reproduction and dissemination of material in this information product. Except where otherwise indicated, material may be copied, downloaded and printed for private study, research and teaching purposes, or for use in non-commercial products or services, provided that appropriate acknowledgement of FAO as the source and copyright holder is given and that FAO’s endorsement of users’ views, products or services is not implied in any way.
    [Show full text]
  • Starch and Flour Extraction and Nutrient Composition of Tuber in Seven Cassava Accessions
    J. Bangladesh Agril. Univ. 10(2): 217–222, 2012 ISSN 1810-3030 Starch and flour extraction and nutrient composition of tuber in seven cassava accessions M. S. A. Fakir, M. Jannat, M.G. Mostafa and H. Seal1 Department of Crop Botany, 1Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh- 2202, Bangladesh, Email: [email protected] Abstract Cassava (Manihot esculenta Crantz) roots (tubers) are used as staple food. Starch extracted from tubers is widely utilized as raw materials in industries. Dry matter (DM) content, starch and flour extraction and proximate composition were investigated in seven cassava accessions (Coc-A1, Kh-A2, Cow-A3, Sa-A4, Me-A5, Va-A6 and Sy-A8.) in 2010- 2011. Leaf DM varied from 20.51% in Me-A5 to 29.01% in Sy-A8; that of stem from 27.24% in Va-A6 to 32.10% (average of Sy-A8, Me-A5 and Sa-A4); and that of tuber from 37.30% in Kh-A2 to 45.26% in Sy-A8. Starch was extracted by blending chopped tuber followed by decantation. Tubers were sliced, sun dried and milled into flour. Tuber starch content (fresh wt. basis) varied between 15.04% in Sy-A8 and 24.97% (average of Coc-A1 and Me-A5); that of peel from 4.54% in Va-A6 to 5.85% in Coc-A1. Crude protein varied from 1.80% (average of Kh-A2, Cow-A3 and Sy-A8) to 4.53% in Va-A6. Crude fiber content varied from 1.95% (average of Sa-A4 and Coc-A1) to 4.27% in Cow-A3.
    [Show full text]
  • 2.3.2. Genetic Modification of Plant Cell Walls for Enhanced Biomass
    Genetic Modification of Plant Cell Walls for Enhanced Biomass Production and Utilization Investigators Chris Somerville, Professor, Department of Biological Sciences, and Director, Carnegie Institution, Department of Plant Biology; Jennifer Milne, Postdoctoral Fellow, Department of Biological Sciences Introduction In 2002, The US Department of Energy released a document entitled “The Vision for Bioenergy and Biobased Products in the US” that envisioned 5% of energy, 20% of transportation fuel and 25% of chemicals being derived from biomass by 2030. A crucial factor in reaching these goals will be the net productivity of the plants used. It is generally accepted that the current practice of converting excess starch production to ethanol does not represent a significant long-term opportunity. By contrast harvesting the “cellulosic biomass” that comprises the body of plants represents an attractive target. A recent study by DOE and USDA estimated that there is approximately 1.4 billion dry tons per year of renewable excess biomass capacity in the US. This is roughly equivalent to the energy content of all imported petroleum. Plant biomass is primarily a mixture of six types of polysaccharides. These can be utilized for energy production in a variety of ways, including direct combustion, gasification, pyrolysis, and enzymatic conversion to ethanol or other organics. In order to maximize the energy efficiency of biomass production it is essential to minimize requirements for fixed nitrogen (~30 Gj/tonne), which is required primarily for protein and lignin synthesis. The polysaccharides that comprise the bulk of biomass do not contain any nitrogen. Thus, from a system engineering perspective, it is desirable to maximize polysaccharide accumulation while minimizing demand for nitrogen.
    [Show full text]
  • Physical And/Or Chemical Modifications of Starch by Thermoplastic Extrusion
    3 Physical and/or Chemical Modifications of Starch by Thermoplastic Extrusion Maria Teresa Pedrosa Silva Clerici Federal University of Alfenas-UNIFAL-MG Brazil 1. Introduction Starch makes up the nutritive reserves of many plants. Starch biosynthesis is a complex process, which may be summarized as during the growing season, the green leaves collect energy from the sun, this energy is transported as a sugar solution to the starch storage cells, and the sugar is converted into starch in the form of tiny granules occupying most of the cell interior. The conversion of sugar into starch takes place through enzymes (Corn Production Source, 2011; Tester et al., 2006). Starch granules are composed of two types of alpha-glucans, amylose and amylopectin, which represent approximately 98–99% of the dry weight. The ratio of the two polysaccharides varies according to the botanical origin of the starch and classifies starch as the ‘waxy’ starches contain less than 15% amylose, ‘normal’ 20–35% and ‘high’ amylose starches greater than about 40% (Tester et al., 2006; Wurzburg, 1989). Amylopectin is a much larger molecule than amylose with a molecular weight and a heavily branched structure built from about 95% ( 1- 4) and 5% ( 1- 6) linkages. Amylopectin unit chains are relatively short compared to amylose molecules with a broad distribution profile. They are typically, 18–25 units long on average (Tester et al., 2006; Wurzburg, 1989). Nutritionally, starch is consumed as an energy source, and it is the most abundant energy source in the human diet as it is present at high amounts in cereals, roots and tubers, which products range from breads, cookies, pastes to consumption as snacks, porridges, or as processed cooked grains (white rice, corn grain) or whole grains (whole grain of rice, wheat, popcorn, etc.).
    [Show full text]