Scientific english for food science

BỘ GIÁO DỤC VÀ ĐÀO TẠO ĐẠI HỌC THÁI NGUYÊN TRƯỜNG ĐẠI HỌC NÔNG LÂM NGUYỄN HỮU NGHỊ SCIENTIFIC ENGLISH FOR FOOD SCIENCE THÁI NGUYÊN 2011 UNIT INTRODUCTION TO FOOD SCIENCE Reading Food science can be defined as the application of the basic sciences and engineering to study the fundamental physical, chemical, and biochemical nature of foods and the principles of food processing Food technology is the use of the information generated by food science in the selection, preservation, processing, packaging, and distribution, as it affects the consumption safe, nutritious and wholesome food As such, food science is a broad discipline which contains within it many specializations such as in food microbiology, food engineering, and food chemistry Because food interacts directly with people, some food scientists are also interested in the psychology of food choice Industry and academic specialists have often differed about the definition of the term food scientist, and what should constitute appropriate formal training Similarly, the major schools offering a degree in food science have not always agreed on the requirements for such a degree The Education Committee of the Institute of Food Technologists (IFT) adopted a set of minimum standards for a university undergraduate curriculum in food science These standards are followed by most universities which offer degrees in food science and reflect the scientific nature of food science The most recent recommended minimum standards include both basic science courses and core food science and technology courses for B.S degree The standards are based on a 120 – semester – hour or 180 – quarter – hour requirement for graduation Courses should carry three to five semester hours or four to eight quarter hours of credit The core food science and technology courses, representing a minimum of 24 semester hours or 36 quarter hours including: Food chemistry covers the basic composition, structure, and properties of foods and the chemistry of changes occurring during processing and utilization Prerequisites should be courses in general chemistry, organic chemistry, and biochemistry Food analysis deals with the principles, methods, and techniques necessary for quantitative physical and chemical analyses of food products and ingredients The analyses should be related to the standards and regulations for food processing Prerequisites include courses in chemistry and one course in food chemistry Food microbiology is the study of the microbial ecology related to foods, the effect of environment on food spoilage and food manufacture, the physical, chemical, and biological destruction of microorganism in foods, the microbiological examination of food stuffs, and public health and sanitation microbiology One course in general microbiology is the prerequisite Food processing covers general characteristics of raw food materials; principles of food preservation, processing factors which influence quality, packaging, water and waste management, and good manufacturing practices and sanitation procedures Food engineering involves study of engineering concepts and unit operation used in food processing Engineering principles should include material and energy balances, thermodynamics, fluid flow, and heat and mass transfer Prerequisites should be one course in physics and two in calculus Vocabularies Science (n) Khoa học Technology (n) Công nghệ Application (n) Sự áp dụng Engineering (n) Kỹ thuật Fundamental (adj) Nền tảng, sở, nguồn gốc Physics (n) Vật lý Chemistry (n) Hoá học Microbiology (n) Vi sinh học Psychology (n) Triết học Biochemistry (n) Hoá sinh Biology (n) Sinh học Calculus (n) Tính toán Principle (n) Nguyên lý Process (n) Chế biến, trình Preservation (n) Bảo quản Packaging (n) Đóng gói, bao gói Distribution (n) Phân phối Consumption (n) Sự tiêu thụ Nutrition (n) Dinh dưỡng Discipline (n) Lĩnh vực Specialization (n) Chuyên môn hoá, chuyên môn Industry (n) Công nghiệp Academy (n) Hoc thuật Degree (n) Bằng cấp Requirement (n) Đòi hỏi, yêu cầu Education (n) Giáo dục Training (n) Đào tạo, tập huấn Committee (n) Hội đồng Institute (n) Viện nghiên cứu Standard (n) Tiêu chuẩn Undergraduate (n) Sinh viên đại học chưa tốt nghiệp Curriculum (n) Chương trình học University (n) Trường đại học Bachelor degree (n) Bằng đại học Semester (n) Kỳ học (một năm kỳ) Quarter (n) Kỳ học (một năm kỳ) Graduation (n) Tốt nghiệp Course (n) Học phần, môn học Credit (n) Tín Composition (n) Thành phần, hợp phần Structure (n) Cấu trúc Property (n) Đặc tính Characteristic (n) Đặc điểm Occur (v) Xảy Utilization (n) Sử dụng, tận dụng Prerequisite (n) Yêu cầu trước tiên Analysis (n) Phân tích Method (n) Phương pháp Quantitative (adj) Định lượng Ingredient (n) Thành phần Regulation (n) Nội quy, quy định Ecology (n) Sinh thái học Spoilage (n) Hư hỏng, thối hỏng Sanitation (n) Vệ sinh Procedure (n) Quy trình Material (n) Vật liệu Energy (n) Năng lượng Thermodynamics (n) Nhiệt động lực học Mass (n) Vật chất Transfer (n) Vận truyển, truyền Exercises Answer the following questions: Give the definition of food science? What does food science contain? What does food chemistry cover? What does food analysis deal with? What does food microbiology study? What does food processing concern about? What does food engineering involve? Which aspects of food science are you interested in? Why? UNIT INTRODUCTION TO MODIFIED ATMOSPHERE PACKAGING Reading Modified atmosphere packaging (MAP) can be defined as the enclosure of food products in a barrier film in which the gaseous environment has been changed or modified to slow respiration rates, reduce microbiological growth and retard enzymatic spoilage with the intent of extending shelf life There are two methods for MAP, modified atmosphere (MA) and controlled atmosphere (CA) In MA, the atmosphere inside package containing a respiring product changes with time due to the consumption of oxygen and production of carbon dioxide that occurs as a result of the respiration process, until eventually an equilibrium concentration of these gases is established in the atmosphere within the package The equilibrium concentrations of these gases in the package headspace is governed by a complex function of the intrinsic respiration rate of the product, the weight of product in the package, and the permeability characteristics of the package to these gases The intrinsic respiration rate of the products and the permeability characteristics of the package increase with temperature, and so can potentially vary considerably over the storage life of the product, depending on the integrity of the cold chain during storage and distribution of the packaged product In CA, the initial headspace gases will be rapidly replaced with a gas composition that has a concentration of oxygen and carbon dioxide that is closer to the optimal levels (2 to 5% oxygen/3 to 10% carbon dioxide) in order to avoid prolonged exposure of the product to suboptimal headspace gas concentrations This can be achieved by simply flushing the package headspace with a suitable gas mixture; however, more recently chemical approaches have been reported that have the commercial advantage of potentially providing a means of avoiding the slow and costly gas-flush step An example of Litchi Litchi (Litchi chinensis Sonn.), native to southern China, is adapted to the warm subtropics, cropping best in regions with brief cool dry frost-free winters and long hot summers with high rainfall and humidity The fruit easily loses its commercial value after harvest due to pericarp browning, quality deterioration and decay (Ray, 1998) Browning of litchi pericarp is still considered to be a major problem affecting its market value During the past two decades, a considerable amount of research work has been carried out on litchi fruit, including analyzing the role of pigments, hormones and some other closely related factors responsible for postharvest browning of litchi fruit, selecting suitable storage temperature and postharvest chemical treatments to prevent browning, control decay and extend storage life Browning of litchi pericarp was thought to be due to degradation of anthocyanidin by polyphenol oxidase (PPO) and peroxidase (POD) and was primarily the result of PPO activity degrading the anthocyanins and producing brown-coloured by-products Since PPO can not oxidize monophenols on odiphenols, the POD was also suggested to play an important role in the browning of litchi pericarp In general, sulfur dioxide treatments have been widely used to control saprophytic surface fungi and prevent peel browning of litchi fruit MAP has been considered to be beneficial to maintain high humidity, essential for prevention of water loss and browning of litchi pericarp CA with low-O2 and high-CO2,have been successfully used to reduce decay, maintain quality and extend storage life in many fruits In recent years, high O2 treatment was considered to be effective in inhibiting enzymic discoloration, preventing anaerobic fermentation reactions, and limiting aerobic and anaerobic microbial growth Vocabularies Modified (adj) Cải biến Controlled (adj) Kiểm soát Atmosphere (n) Khí Packaging (n) Bao gói Enclosure (n) Ngăn cản, rào cản Film (n) Màng Respiration (n) Hô hấp Spoilage (n) Sự hư hỏng thực phẩm Extending (n) Kéo dài Shelf life (n) Thời gian bảo quản Modification (n) Sự cải biến Consumption (n) Sự tiêu thụ As a result of (clause) Do kết Equilibrium (n) Cân Establish (v) Thiết lập Headspace (n) Vùng khoảng không phía nông sản Permeability (n) Khả thấm khí Integrity (n) Tính toàn bộ, toàn vẹn Composition (n) Thành phần, hợp phần Prolonged (adj) Kéo dài Exposure (v) Phơi bày, tiếp xúc Flushing (n) Phun Subtropics (n) Cận nhiệt đới Pericarp (n) Vỏ Peel (n) Vỏ Deterioration (n) Sự hư hỏng Decay (n) Sự thối hỏng Browning (n) Sự xẫm màu Pigment (n) Chất màu Hormone (n) Hóc môn Postharvest (n, adj) Sau thu hoạch Degradation (n) Sự phân huỷ Anthocyanin (n) Anthocyanin Saprophytic (adj) Hoại sinh Fungi (n) Nấm mốc Humidity (n) Độ ẩm Anaerobic (adj) Yếm khí Aerobic (adj) Hảo khí Fermentation (n) Lên men Exercises Answer the following questions Give the definition of MAP? Why does the atmosphere inside package change? What is the equilibrium concentration of the gases in the package headspace governed? What is the optimal gas composition for CA? What are the main differences between CA and MA? UNIT INTRODUCTION TO STARCH MODIFICATION Reading Native starches have many disadvantages for industrial applications such as insolubility in cold water, loss of viscosity, and thickening power after cooking In addition, retrogradation occurs after loss of ordered structure on starch gelatinization, which results in syneresis or water separation in starchy food systems However, these shortcomings of native starch could be overcome, for example, by introducing small amounts of ionic or hydrophobic groups onto the molecules The modifications alter the properties of starch, including solution viscosity, association behavior, and shelf life stability in final products The functionality of starch can be modified through physical, chemical, and biotechnological means Another purpose of starch modification is to stabilize starch granules during processing and make starch suitable for many food and industrial applications Starch can be physically modified to improve water solubility and to change particle size The physical modification methods involve the treatment of native starch granules under different temperature/moisture combinations, pressure, shear, and irradiation Physical modification also includes mechanical attrition to alter the physical size of starch granules Starch is widely modified by chemical methods The most common chemical modification processes are acid treatment, cross-linking, oxidation, and substitution, including esterification and etherification Chemical modification The most common chemical modification includes: oxidation, esterification, and etherification The chemical modification of starch results in enhanced molecular stability against mechanical shearing, acidic, and high temperature hydrolysis; obtaining desired viscosity; increasing interaction with ion, electronegative, or electropositive substances; and reducing the retrogradation rate of unmodified starch Physical modification Physical modification of starch can be applied alone or with chemical reactions to change the granular structure and convert native starch into cold water soluble starch or into small crystallite starch Cold water soluble starch is prepared by pregelatinization of native starch slurry, followed by drum drying Because of 10 pregelatinization and drying, the granular integrity is lost and paste viscosity of starch is reduced Therefore, the modified starch is cold water soluble Heat-moisture and annealing treatments induce the rapid migration or rearrangement of the amylose molecules in the granules to form intermolecular bonds between the amylose molecules and/or between the amylase molecules and the amylopectin molecules Extrusion modification of starch is a process that uses the molten phase of high solid concentration to transform starch while maintaining a macromolecular structure Vocabularies Starch (n) Tinh bột Modify (v) Biến đổi, biến hình Modification (n) Sự biến đổi, biến tính Solubility (n) Khả hoà tan Viscosity (n) Độ nhớt Thickening power (n) Khả làm đầy, khẳ làm đặc Gelatinization (n) Quá trình hồ hoá, hồ tinh bột Retrogradation (n) Sự thoái hoá hồ tinh bột Syneresis (n) Sự chảy dịch, tách nước Hydrophobic (adj) Kỵ nước Hydrophilic (adj) Ưa nước Granule (n) Hạt Particle (adj) Hạt, tiểu phần, phần nhỏ Shear (n, v) Cắt Irradiation (n) Tia sang Substitution (n) Sự thay Esterification (n) Este hoá Etherification (n) Ete hoá Hydrolysis (n) Thuỷ phân Electronegative (adj) Mang điện âm 11 Electropositive (adj) Mang điện dương Crystalline (adj) Kết tinh, tinh thể Pregelatinization (n) Hồ hoá trước (hồ hoá sơ bộ) Slurry (n) Huyền phù Drum (n) Cái trống Annealing (adj) Gia nhiệt nhiệt độ cao (hồ hoá tinh bột) Migration (n) Sự di chuyển Extrusion (n) Sự ép đùn Molten (adj) Nấu chảy Exercises Answer the following questions What are the disadvantages of native starch? What can modify functionality of starch? What does the modification alter the properties of starch? What is another purpose of starch modification? What does physical modification method involve? What are the most common chemical modification processes? 12 UNIT CARBON SOURCES FOR MICROORGANISIM NUTRITION Reading A carbon source is necessary to provide the cell with energy as well as the material with which to grow and synthesise arrange of primary and secondary metabolites The best energy source depends on the type of organism utilised, e.g autotroph, chemotroph, etc There is obviously a wide range of carbon sources and the one chosen should be appropriate to the organism but also to the economics of the process At research scale the latter tends to be less important, but it should be borne in mind if the objective of the program is to develop an industrially relevant process This section will look at several carbon sources and indicate the advantages and disadvantages of each A typical microorganism is approximately 50% carbon, making carbon the most significant substrate and care should be taken to ensure that the carbon concentration does not become limiting The yield of biomass on carbon is approximately 0.5, which means that if a biomass concentration of 50 gL−1 is required, 100 gL−1 of the carbon source must be supplied, although not necessarily all at once if fed-batch culture is being utilised The great majority of laboratory and industrial fermentations tend to use a very limited range of easily utilisable substrates to supply the energy and C requirements of cultures This does not imply that other C and energy sources could not be used, just that this limited range is usually available and methods for preparing and analysing the consumption rates of such substrates are well understood The production of pharmaceuticals, especially biopharmaceuticals by fermentation, takes place in the context of an industry that is, with the possible exception of the nuclear industry, perhaps the most regulated in the world This fact accounts for a degree of ‘conservatism’ in terms of nutrient supply Glucose Glucose is universally acceptable for growth of most cell lines, for instance in animal, plant or microorganisms Supplied as a powder in the pure form, the substrate is readily available, reliable, easily stored, easily handled and has no significant implications for health and safety These qualities make glucose a popular choice of carbon source There some drawbacks to using glucose, notably: 13 (i) the possibility of the organism suffering from the ‘Crabtree effect’ if glucose is over supplied in the initial stages of growth; (ii) the loss of available substrate to the Maillard reaction, which can occur if glucose is sterilised with a nitrogen source present Both of these situations can be overcome readily, by careful monitoring and control of glucose feed in the first case and by either sterilising the substrates separately or by using filtration sterilisation methods in the second A popular method of supplying glucose on a larger scale is to use glucose syrups, manufactured by the hydrolysis of starch (a substrate which itself tends to be insoluble and consequently unavailable to the cells, difficult to handle, but is readily hydrolysed to glucose) The drawbacks remain the same, with the additional complications of transportation, storage and handling of a liquid Formulation of the medium and delivery to the bioreactor may also be considerations that have to be taken into account The main advantage to using glucose syrups is cost, as it is significantly cheaper than powdered glucose Sucrose Often the sugar of choice in research laboratories, sucrose, is utilised by many but not all cell lines Commercially available sucrose comes in many forms and grades, from pure granulated forms to complex molasses solutions (above) Sucrose does not tend to suffer from the same drawbacks as glucose and, although it can be subject to caramelisation when over sterilised, generally it can be autoclaved/sterilised with nitrogen compounds without the same problems as glucose If using molasses, sufficient cold storage must be available to handle the needs of the laboratory as the range of different substrate available means that the molasses can be readily contaminated, and although sterilisation can destroy any contaminating organisms, the amount of available sucrose to the organism of choice will decrease Again mixing of molasses from several batches can help iron out some variability contributed by this source Vocabularies Cell (n) Tế bào Energy (n) Năng lượng Primary (adj) Sơ cấp Secondary (adj) Thứ cấp Metabolite (n) Sản phẩm trình chuyển hoá, trao đổi chất 14 Autotroph (n) Sinh vật tự dưỡng Chemotroph (n) Sinh vật dị dưỡng Bear in mind (phase) Chú ý, suy ngẫm Substrate (n) Cơ chất Fed-batch (n) Nuôi cấy có bổ sung dinh dưỡng Majority (n) Sự quan tâm, phần lớn, đa số Fermentation (n) Sự lên men Culture (n/v) Nuôi cấy vi sinh vật Pharmaceutical (adj) Thuộc dược học/sản phẩm dược Account for (phase) Giải thích nguyên nhân Glucose (n) Đường glucose Sucrose (n) Đường sacarose Suffer from (phase) Chịu đựng Initial (adj) Ban đầu Maillard reaction (n) Phản ứng Maillard Sterilize (v) Tiệt trùng/hấp tiệt trùng Filtration (n) Sự lọc Hydrolysis (v) Thuỷ phân Insoluble (adj) Không tan Soluble (adj) Có thể tan Bioreactor (n) Tủ nuôi cấy Molasses (n) Đường mật Caramelization (n) Phản ứng caramen hoá Autoclave (n) Hấp Iron out (phase) Giải Exercises Answer the following questions What carbon sources provide microorganism cells? How could we choose the carbon sources? 15 If we want to have 10 g/l biomass, how much carbon we need to supply? How laboratory and industrial fermentations tend to use carbon sources? Why they limit the range of carbon sources using for fermentation? What are the advantages of glucose? What are the drawbacks of glucose? How were glucose syrups manufactured? 16 UNIT THE LABORATORY NOTEBOOK Reading The laboratory experience is not finished when you complete the experimental procedure and leave the laboratory All scientists have the obligation to prepare written reports of the results of experimental work Since this record may be studied by many individuals, it must be completed in a clear, concise and accurate manner This means that procedural detail, observations and results must be recorded in a laboratory notebook while the experiment is being performed The notebook should be hardbound with quadrille-ruled (gridded) pages and used only for the biochemistry laboratory This provides a durable, permanent record and the potential for construction of graphs, charts, etc It is recommended that the first one or two pages of the notebook be used for a constantly updated table of contents Although your instructor may have his or her own rules for preparation of the notebook, the most readable notebooks are those in which only the right - hand pages are used for record keeping The left hand pages may be used for your own notes, reminders and calculations DETAILS OF EXPERIMENTAL WRITE - UP Introduction This section begins with a three or four sentence statement of the objective or purpose of the experiment For preparing this statement, ask yourself, “What are the goals of this experiment? ” This statement is followed by a brief discussion of the theory behind the experiment If a new technique or instrumental method is introduced, give a brief description of the method Include chemical or biochemical reactions when appropriate Experiment Begin this section with a list of all reagents and materials used in the experiment The sources of all chemical and the concentrations of solutions should be listed Instrumentation is listed with reference to company name and model number A flowchart to describe the stepwise procedure for the experiment should be included after the list of equipment Experiment (a) Table of materials and reagents (b) List of equipment 17 (c) Flowchart (d) Record of procedure Data and Calculations (a) Record of all raw data (b) Method of calculation with statistical analysis (c) Enter data in tables, graphs or figures when appropriate For the early experiments, a flowchart is provided Flowcharts for later experiments should be designed by the student The write-up to this point is to be completed as a Prelab assignment The experimental procedure followed is then recorded in your notebook as you proceed through the experiment The detail should be sufficient so that a fellow student can use your notebook as a guide You should include observations, such as color changes or gas evolution, made during the experiment Data and Calculations All raw data from the experiment are to be recorded directly in your notebook, not on separate sheets of paper Calculations involving the data must be included for at least one series of measurements Proper statistical analysis must be included in this section For many experiments, the clearest presentation of data is in a tabular or graphical form The Analysis of Results section following each experimental procedure in this book describes the preparation of graphs and tables These must all be included in your notebook Results and Discussion This is the most important section of your write-up, because it answers the questions: “Did you achieve your proposed goals and objectives? ” and ” What is the significance of the data?” Any conclusion that you make must be supported by experimental results It is often possible to compare your data with known values and results from the literature If this is feasible, calculate percentage error and explain any differences Note if any problems were encountered in the experiments All library references (books and journal articles) that were used to write up the experiment should be listed at the end The standard format to follow for a book or journal listing is shown at the end of this chapter in the reference section 18 Everyone has his or her own writing style, some better than others It is imperative that you continually try to improve your writing skills When your instructor reviews your write-up, he or she should include helpful writing tips in the grading Vocabularies Laboratory (n) Phòng thí nghiệm Procedure (n) Các bước tiến hành Obligation (n) Nghĩa vụ Reports (n) Báo cáo Results (n) Kết Experiment (n) Thí nghiệm Individuals (n) Cá nhân Concise (adj) Ngắn gọn, xúc tích Detail (n)(adj) Chi tiết Observations (n) Quan sát Notebook (n) Sổ ghi chép Performed (v) Thực hiện, tiến hành Durable (adj) Lâu, bền Permanent (adj) Lâu dài, vĩnh cửu Construction (n) Xây dựng Graphs (n) Đồ thị, biểu đồ Charts (n) Đồ thị, biểu đồ Recommended (v) Khuyến nghị Constantly (adv) Luôn luôn, liên tục Updated (v) Cập nhật Table of contents (n) Mục lục Instructor/supervisor (n) Giáo viên hướng dẫn Introduction (n) Giới thiệu, lời nói đầu, mở đầu Statement (n) Sự phát biểu, tuyên bố Objective (n) Mục tiêu 19 Purpose (n) Mục đích Goals (n) Mục đích, mục tiêu Discussion (n) Thảo luận Instrument (n) Thiết bị đo đạc, dụng cụ, công cụ Method (n) Phương pháp Description (n) Mô tả Appropriate (adj) Phù hợp Materials (n) Vật liệu Sources (n) Nguồn Concentrations (n) Nồng độ Reference (n) Tài liệu tham khảo Assignment (n) Bài tập nhà Data (n) Số liệu thí nghiệm Calculation (n) Tính toán Measurement (n) Sự đo đạc Statistical analysis (n) Phân tích thống kê Presentation (n) Sự trình bày Achieve (v) Đạt Propose (v) Đề xuất, dự định Significance (n) Ý nghĩa Conclusion (n) Kết luận Support (v)(n) Hỗ trợ Literature (n) Tài liệu Feasible (adj) Khả thi Percentage (n) Tỷ lệ, phần Encounter (v) Gặp phải, đối mặt Journal (n) Tạp chí Articles (n) Bài báo tạp chí Imperative (adj) Cấp bách, khẩn thiết 20 Review (v) Tổng quan Exercises Answer the following questions What are the full tasks of scientist when doing experiments in laboratory? How must we complete the written reports of the experimental results? How many steps are there in experimental write-up? What are the main contents of the introduction part? What is the laboratory notebook? Say a few words about calculations of experimental works? Why should we need discussion of experimental results? 21 ... standards for a university undergraduate curriculum in food science These standards are followed by most universities which offer degrees in food science and reflect the scientific nature of food science. .. the definition of food science? What does food science contain? What does food chemistry cover? What does food analysis deal with? What does food microbiology study? What does food processing concern... wholesome food As such, food science is a broad discipline which contains within it many specializations such as in food microbiology, food engineering, and food chemistry Because food interacts