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Food is the basic need for the existence of humanity. Engineering is the application of science for the benefit of mankind. The food engineering domain includes the application of basics of food, physics, biochemistry, microbiology, and mathematics to such operations as heating, cooling, drying, cooking, size reduction, conveyance, pasteurization, sterilization, filtration, mixing, and extraction for appropriate process and equipment design, monitoring, and control. Food is perceived as a very important component of human wellness, which is far more than just nutrition and health. Food has a spiritual dimension as well. This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explains concepts, equipment, and applications in such a manner so as to strengthen the capability of the student as an engineer in and a consultant to the food industry. It includes latest technological developments, thus updating its contents and enhancing its usefulness in empowering students to compete globally.

Pages: 114

No chapter abstract available.

Pages: 6

Understanding the units and measurements is very important as it deals with the tool of comparison and in establishing the validity of any theory. For understanding the basic food processing operations and machineries, for comparing the different methods and equipment as well as for analyzing the economics of the systems, it is important to have a proper knowledge of the units and measurements. The dimension of a physical quantity is more fundamental than some scale unit that is used to express the amount of that quantity. This chapter presents a concise treatment of dimensions, units, measurement, and analysis relevant to food engineering. The four dimensions more frequently used in food processing are mass, length, time, and temperature. Property of a given system is any of its characteristic. Mass, pressure, temperature, thermal conductivity, volume, and viscosity are a few examples of properties. Measured values in an experiment are often needed to undergo arithmetic operations to arrive at final values.

Pages: 14

Material and energy balances form the bedrock of food processing operations and, therefore, are essential for those connected to food processing and industry. The application of material balance is important in calculating the yield from a process or to know the quantity of raw materials required for a particular output and for control of processing operations. For any commercial manufacturing process, first the mass balance is carried out during the product development stage, then in pilot scale operation so that the masses of different streams can be calculated for the commercial process. Finally, the mass balance is carried out for the commercial process to check if there is any variation from the earlier predicted values and corrective measures are taken. The material and energy balances are based on the laws of conservation of mass and energy.

Pages: 10

The concept of the rate of reaction or reaction speed is important in food processing operations. Most of the reactions occurring in food involve conversion of one component to another. A common example is conversion of sucrose to glucose and fructose. Many forms of spoilage of food and degradation of nutrients occur due to chemical reactions within the food. Hence, a knowledge of the rate of reaction is required to decide the processing parameters or to determine the potential shelf life of any food. In any chemical reaction the change in concentration of the reacting substances affects the rate of reaction. This chapter gives a comparison of different orders of reactions. It describes the factors influencing reaction rate: Nature of the reaction; Concentration of reactants; Pressure; and Temperature. The Arrhenius equation is used to show the temperature dependence of reaction rates. The changes in the rates of reactions in food with temperature are also described reasonably by the Arrhenius equation.

Pages: 14

The calculation of air required during convective air drying needs knowing the physical and thermal conditions of the air. These conditions can be expressed in terms of temperature, humidity ratio, relative humidity, enthalpy, and explain the capability of the drying air to absorb moisture and the extent to which the commodity could be dried. The study of moist air is known as psychrometry. When water vapor is mixed with dry air, the mixture is termed moist air. A knowledge of moist air properties is necessary for studying the drying of materials and designing of drying systems using natural or heated air. The different psychrometric properties of air-water vapor mixture are dry bulb temperature and water vapor partial pressure at saturation. An increase in moist air temperature leads to an increase in the saturation vapor pressure of the moist air and the air at higher temperature can hold more moisture before saturation.

Pages: 14

Fluid flow and heat and mass transfer are two important processes involved in food processing. Heat and mass transfers occur in evaporation, drying, freezing, pasteurization, sterilization, and so on. There are several liquid foods. There are applications of steam and compressed air, both gases, in food processing. Therefore, basic concepts of fluid flow are important in understanding different food processing operations. This chapter discusses some properties of fluids and characteristics of fluid flow important in food processing applications. It also discusses heat transfer. Viscosities of liquids and gases respond differently to temperature changes. There are different types of fluid flow that are encountered in practice. Fluid flow can be either steady or unsteady, uniform or non-uniform, rotational or irrotational, laminar or non-laminar, compressible or incompressible flows, and one dimensional or multi-dimensional. Fluid properties such as density and viscosity change during processing, which also need to be considered during the design of the food processing equipment.

Pages: 32

Heat transfer differs from thermodynamics in that thermodynamics is conceptually based on equilibrium or infinitesimal deviations from equilibrium while heat transfer occurs from non-equilibrium conditions, specifically, finite temperature differences. Heat or thermal energy transfer in a given situation can occur due to either one or more of the three modes that is conduction, radiation, and convection. This chapter discusses the internal and external resistances to heat transfer when combined conduction and convection take place. When radiation falls on the surface of an object, a fraction of it is absorbed by the object, a fraction is reflected back, and the remaining radiation is transmitted through the object. Accordingly, these phenomena are known as absorptance, reflectance, and transmittance and the fractions are denoted as absorptivity, reflectivity, and transmissivity. Mass transfer is very important in food processing. The chapter also discusses some general laws and theories of mass transfer.

Pages: 10

The ability to cool and bring down the temperature of an object or an enclosure to a desired extent have been revolutionary developments as far as human comfort and food processing are concerned. The ability to lower the temperatures of food products has made it possible to store them for longer periods, transport them over longer distances, and maintain their quality and safety until their consumption. There are several temperature reduction technologies. This chapter discusses the basic principles and equipment that are used in temperature reduction: refrigeration and air conditioning. There are two ways in which the refrigeration cycle can function. One way is vapor compression refrigeration cycle and the other is vapor absorption refrigeration cycle. For food applications, temperatures below 223 K or lower are considered cryogenic. There are two ways of reaching low temperatures; through the use of cryogens or by mechanical coolers. The chapter provides the properties of some common refrigerants.

Pages: 12

It is very important that both raw food and processed food be kept protected from microorganisms. Among the different parameters that control the growth of microorganisms in food, temperature, pH, and water activity are very important. A lower water activity gives a longer shelf life. During food processing operations, the process engineers consider water activity to decide whether the food is shelf-stable or not. Often, water activity is taken as a critical control point in monitoring food safety. This chapter discusses how the death rate of microorganisms depends on the processing parameters that is the temperature and time of processing. It also discusses how the type and population of bacteria decide the processing parameters. The chapter then discusses water activity and thermo-bacteriology. Water activity values can be measured by either a resistive electrolytic or a capacitance method or by measuring the dew point with a dew point hygrometer.

Pages: 374

No chapter abstract available.

Pages: 118

No chapter abstract available.

Pages: 20

Some primary processing operations are carried out in the food production/processing areas before the food is actually processed. Unit operations include cleaning/washing, sorting, and grading. Peeling of fruits and vegetables is also a common unit operation in food processing plants. These unit operations help to improve the quality of the raw materials and to prepare the product for further processing. This chapter discusses the principles and different equipment used for these operations and their working principles. The process of cleaning is based on the product and the type and nature of the admixtures/ dirt. The cleaning methods can be broadly classified under two categories as: dry cleaning and wet cleaning. The chapter shows some examples of the properties used for cleaning and separation processes, including sorting and grading in food grains/ horticultural products and the type of equipment used. It discusses the major modes of washing.

Pages: 24

Size reduction, also known as comminution, is an essential unit operation in food processing. Many products, such as meal, powder, flour, and split, are obtained through size reduction. Fruits and vegetables are cut and sliced before processing or cooking. Polishing of rice and homogenization of milk also involve size reduction operations. There are two major categories of size reduction on the basis of the raw material being either solid or liquid. Size reduction of solids can be achieved through impact, compression, abrasion, and cutting. For liquids, size reduction is achieved by homogenization or atomization. This chapter defines some laws that have been developed for energy requirement for size reduction such as Kick's Law, Rittinger's Law, and Bond's Law. It discusses the general categorization of the size reduction equipment. The chapter provides some important points to know while using the size reduction machines.

Pages: 42

Separation of components is often needed in food industries, for sorting, cleaning, classification, etc. The separation of impurities from water, fat from milk, pulp from juices, oil from oil-bearing materials, and powder from air/gas coming out of pneumatic conveyors/spray dryers are all mechanical separation operations. The main processes used for the separation of different components of food are screening, filtration, settling and sedimentation, centrifugation and expression. This chapter focuses on the different types of mechanical separators. It also discusses innovative separation techniques, such as membrane separation and supercritical fluid extraction. Many types of filters are used in the food industry as well as other process industries to cater to the needs of the whole array of materials and diverse process conditions. The equipment used for commercial filtration is classified in a number of ways. The common type of classification can be as batch type or continuous type systems.

Pages: 12

The dictionary meaning of extraction is to remove some material of interest from a solid or liquid matrix. The material of interest may itself have economic value or its extraction increases the economic value of the remaining feed material or both the extract and the remaining feed have increased economic value. Extraction, as a separation process, has found applications in such diverse fields as mining, metallurgy, chemical engineering, medicine, food, and agriculture. In food processing, extraction is applied on the raw materials and/or intermediate products to improve the quality of the finished products. Extraction is a composite process consisting of mixing, diffusion, phase equilibrium, and solubility. The supercritical fluid extraction can be used as a technique for new food preparations. Effectiveness of solid-liquid extraction in the food industry is considerably enhanced by subjecting the feed to pulsed electric field. Microwave-assisted extraction technology is gaining increased acceptability on account of savings in energy, water, and solvents.

Pages: 18

In the food industry, mixing is used for altering the quality of a product and/or to develop new products. The mixing operations used in the food industry can be broadly discussed under three categories: mixing of dry materials as powders, granular solids, mixing of liquids as concentrated juice and sugar, water and milk powder, and mixing of pastes, for example, salt in ginger paste, salt/ sugar with dough, and so on. Mixers are usually specifically designed for the type of products, for example, powders, pastes, or liquids, and so on as per the requirement of power and degree of uniformity required. Achieving a stable emulsion of two or more immiscible liquids by thorough mixing is the objective of emulsification. The selection of a proper emulsifying agent and stabilizer during food preparation is as important as the control over the homogenization conditions, as these affect the texture and mouthfeel of the food.

Pages: 122

No chapter abstract available.

Pages: 24

Heat exchange is a common unit operation in food processing industries. The liquid foods are pasteurized and sterilized by heating them in different types of heat exchangers. Hot water blanching involves dipping food in hot water and the hot water is produced by heat exchangers. The heat exchangers are also integral parts of evaporation systems. The heat exchangers can be classified in many ways depending on the type of heat transfer process, such as direct type or indirect type, or based on construction or fluid flow patterns. The classification of heat exchange equipment is based on such factors as number of fluids, mechanism of heat transfer, heat transfer process, flow arrangements, and construction features. Classification on the basis of construction features leads to the heat exchangers being plate-type, tubular, extended surface, and regenerative. There are some other equipment as bulk milk coolers, spray coolers, cascade coolers, and so on where different types of heat exchange methods are used.

Pages: 28

In the food processing industry, heat processing or thermal processing methods, such as pasteurization, sterilization, and blanching, are very common. As sterilization eliminates almost all microorganisms and inhibits enzyme activity, it is possible to store a properly packaged product for a long period at normal temperature, even up to six months or more. But pasteurization does not kill all microorganisms, and, hence, these residual microorganisms can grow under favorable conditions and can spoil the food. The advantage of pasteurization is that, unlike sterilization, it does not notably change the organoleptic and eating qualities of food. As the process of sterilization was initially developed for treating products within cans, sterilization is also otherwise known as canning. Since nearly all fluid milk and ice cream mixes, and so on are homogenized, homogenizers are integrated to the continuous pasteurization process.

Pages: 28

The basic evaporation process consists of the heat transfer to the feed followed by vaporization of water from it. Thus, a heat exchange system is an essential part of the evaporator. Steam is the common heating medium in commercial evaporators. The evaporation rate is dependent on the rate of heat transfer to the food and the mass transfer from food as vapor. A higher temperature difference between the steam and the feed will increase the rate of evaporation. An evaporator consists of a heat exchanger that transfers heat from steam to the feed; a chamber or other device for separating the vapor from the feed; and a vacuum pump. The performance of an evaporator can be expressed in terms of its capacity and economy. Evaporators may be single effect or multiple effect systems depending on the number of stages employed for evaporation.

Pages: 10

Applications of distillation in food industries include manufacturing of potable alcohols like whisky, brandy, wine, and beer. The fermented slurry undergoes several distillation processes depending upon the characteristics of the slurry and the final product using batch and/or continuous distillation. Steam distillation, either alone or in combination with vacuum distillation, is used for separating essential oils from herbs, flowers, seeds, and so on. Deodorization of certain processed products such as oils, fats, and plant-based milks are also carried out using appropriate methods of distillation. Volatility is the ease with which the liquid turns into vapors. Batch distillation without any reflux does not produce high quality products. Flash distillation is effective in separating the liquids in a mixture that boils at widely different temperatures. Vacuum distillation along with steam distillation could be utilized for certain class of fluids. Steam distillation has high relevance in the distillation of volatile oils and fragrances. It is used to eliminate unwanted odors and foul smells.

Pages: 8

Crystallization is that technique of material separation where one material is permitted to form crystals in a liquid for subsequently separating it out. It is one of the several processes of material separation, whereby crystals are formed, as opposed to amorphous powdery material, of the solute in a homogenous liquid solution or melt. In the domain of food processing, crystallization finds its utility in the sugar industry where not only sucrose but also glucose, lactose, and other types of sweeteners are crystalized. Crystallization is also used in the manufacture of salt, citric acid, and ice cream. Crystallization is a four-step process: creation of a super-saturated state, formation of nuclei, growth of nuclei, and crystal perfection or continued growth. Essential features in a crystallization plant are, mechanism to raise the concentration of the desired solute to a predetermined level, initiation of nucleation and crystal growth, separation of crystals from the residual mother liquor, and drying of crystals, and elutriation.

Pages: 6

Extrusion is the process of forcing something out using a device; the device is extruder and the “something” being forced out is extrudate. When it is applied to food materials, moist solids and slurries can be forced out of small holes to impart specific characteristics to the output. Vermicelli and many other savouries have been made in this manner for millennia. Simple devices are used to obtain the extruded products for subsequent drying or frying. Different types of products can be obtained from the extruders based on starch, sugar, cereal, and proteins as directly expanded products, such as corn curls and breakfast cereals; unexpanded products, such as pasta; co-extruded products, such as jelly-filled cores and fruit-based cereals; candies, such as liquorice and chewing gum; and texturized products, such as meat analogues. In addition, the extruders can also be used to prepare half products, such as potato pellets and modified fat mimics and starches.

Pages: 16

This chapter discusses different novel heating technologies for food applications, such as ohmic heating, infrared heating, microwave, and radio frequency heating. These technologies are reported to yield better quality products as compared to conventional heating methods and also to impart desirable effects on foods. An ohmic heating system, also known as a joule heater, is an electrical heater that uses electrical resistance to generate heat, which, in turn, provides energy for food processing. The infrared heating and drying involves absorption of thermal spectrum of electromagnetic radiation by the materials. Dielectric heating, which includes the use of microwaves and radio frequency radiation, have enormous potential for heating and processing in food industries. The microwaves are electromagnetic waves with frequencies ranging between 300 MHz and 300 GHz. The chapter gives the frequencies assigned by the Federal Communications Commission for industrial, scientific, and medical use to avoid interference with telecommunication.

Pages: 74

No chapter abstract available.

Pages: 52

Drying of food refers to the removal of moisture to a recommended level for prolonged storage and for keeping it in good condition until further processing. The food grains, fruits, and vegetables, etc. are harvested at high moisture contents and the recommended levels of moisture to which the commodities are to be dried depend on the nature of the commodities and their use. Drying is a thermo-physical process. There is heating of the commodity to increase the vapor pressure of the moisture within the commodity. The extra moisture present in a commodity than the equilibrium moisture is known as the free moisture. In other words, during the process of drying and storage only the free moisture available in the material can be removed. The moisture that is retained by the commodity in response to the corresponding atmosphere is reduced, i.e., the equilibrium moisture content is lowered.

Pages: 20

Foods during storage undergo physical (such as moisture loss), physiological (senescence, respiration, and ripening), microbiological (growth of microorganisms), and/or biochemical (lipid oxidation, browning, and pigment degradation) changes affecting their quality and shelf life. Chilling involves reducing the temperature of food to a level above the freezing point of water and maintaining that temperature during the storage period. As the temperature is reduced, the rates of biochemical and microbiological changes are reduced, which helps in extending the shelf life of food, both fresh and processed. The knowledge of eutectic temperatures of different food constituents helps in designing the heat load of the freezing equipment. The calculation of the freezing time is difficult due to many reasons, which include the irregular shape and size of food, changes in the properties of food during freezing, and variation in rates of ice crystal formation within different regions of food.

Pages: 26

No chapter abstract available.

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Many foods are heat sensitive due to the presence of minerals, vitamins, nutrients with functional properties as antioxidants, and bioactive compounds. The non-thermal processing methods that are being explored include high-pressure processing and high-pressure homogenization, low pressure, pulsed electric field, high-voltage arc discharge, oscillating magnetic fields, different forms of ionizing radiations (gamma irradiation, electron beam), gases (ozone, chlorine dioxide, cold plasma), light (ultraviolet, pulsed light, high-intensity laser), ultrasound and chemical sanitizers (chlorine, surfactants). Vacuum cooling can be applied to different fruits and vegetables, lettuce and mushrooms, etc. There is the possibility of vacuum cooling for meat and bakery products as well. High-pressure processing has proved more effective when combined with other non-thermal technologies, such as gamma irradiation, ultrasound, and anti-microbial agents, such as lacticin, nisin, etc. Pulsed light is used commercially for disinfecting food contact surfaces and packaging material and equipment, but commercial application for foods is limited.

Pages: 4

Food biotechnology is the branch of biotechnology that aims at enhancing food qualities or yield or to develop new and improved food or food-related products. The primary goal of food biotechnology today is to provide more abundant, less expensive, more nutritive, and safer food to address the needs of the growing population globally in a sustainable way. Food fermentation is an important area of application of biotechnology in food processing. Fermented dairy products, pickles, vinegar, sauerkraut, and other fermented products are essentially obtained through the process of controlled fermentation. Many cost-effective and cost-competitive bio-preservatives are available on the market. Currently, efforts are being made to develop genetically designed milk, food grade bio-preservatives, functional foods, bioactive peptides, oral vaccines, recombinant enzymes, cultures, flavors, colors, and bacteriocins for bio-preservation. Integration of biotechnology with nanotechnology would unleash tremendous opportunities.

Pages: 4

Nanotechnology involves working with matter at nanoscale for design, characterization, production, and use of new products. Nanomaterials may include nanoparticles, nanotubes, fullerenes, nano-fibers, nano-whiskers, and nanosheets. There are two approaches for nanomaterial manufacturing: top-down and bottom-up. Smaller components arrange themselves into more complex assemblies in the bottom-up approach while the top-down approach seeks to create nanoscale materials and devices by using larger, externally controlled components. Potential applications of nanotechnology are immense and pervade all domains. Nanostructured food ingredients and food nano-sensing are two main categories of the applications in food sector. Nanostructured food ingredients encompass a wide range of interventions in food processing, including packaging. These have been found to improve the shelf life of different foods and to improve the taste and texture of foods. It can be appreciated that nanotechnology has enormous potential for its use in food sector. When combined with biotechnology, the potential grows beyond comprehension.

Pages: 32

No chapter abstract available.

Pages: 16

The shelf life of a food product is extended or shortened by the way it is packaged. The packaging also helps in giving the customer information about the product. Basically, it ensures safe delivery to the end user in a sound condition. With the significant growth of the plastic industry and use in food and other packaging, it has also become important to have a quality waste management plan. Thus, the five Rs of waste management have become significantly important. These are renew, reduce, reuse, recycle, and recover. In food industries, it is important that proper quantity of the prepared food is filled in the packages, which may be made up of plastic, glass, metal, or other materials. Different types of metering and filling devices are available for the purpose. In the shrink-packaging machine, three kinds of film wrapping methods can be used depending on the items, namely, open at both ends, open at one end, and fully enclosed.

Pages: 14

Raw materials, partially processed products, end products, packaging materials, fuel and other utilities, wastes, containers, etc. need to be conveyed from one section to another in a food processing plant. Although people are engaged for such operations in most small and medium enterprises, mechanical handling is preferable as it involves less labor, reduces drudgery, and makes the operations more efficient. Common conveying equipment used in the food industry include the belt conveyor, roller conveyor, screw (auger) conveyor, drag/chain/tow conveyor, bucket elevator, vibrating conveyor, and pneumatic conveyor. In addition, other conveyors, such as chute, overhead, vertical, walking beam, and wheel conveyors, are also used. In the food processing plant, the raw and partially processed products, fuel, containers, packaging materials, etc. are transferred into the plant and shifted from one place to the other within the plant.

Pages: 20

No chapter abstract available.

Pages: 6

A long shelf life for a food product, processed or fresh, is expected to ensure its effective utilization. The purpose of this chapter on shelf-life estimation is to provide a basic knowledge about various considerations needed for determining the product shelf life. The water activity and temperature together are the two most important factor that affect the shelf life of food products. Food grains could remain in good edible condition for several years because of lower water activity. The factors that influence the shelf life of a food product can be grouped under extrinsic and intrinsic factors. Shelf-life deterioration of a food product may be a function of one or more of the intrinsic and extrinsic factors. Sensors can be used as dynamic and simple methods to evaluate shelf life. Sensors aim to signal the shelf-life deterioration and to indicate the time when the product needs to be pulled out of the supply chain.

Pages: 6

Food quality and safety are essential features of food and its trade today. Food hygiene is the guiding principle for preservation and processing of food such that safety of the food for its intended consumption is ensured. While food hygiene and food safety are related, they are not the same. Food safety consists of all the important practices that any business must carry out to render the food fit for its intended consumption. Contamination is the main concern for food hygiene, leading, subsequently, to public health concern and trade disputes. Food quality takes into consideration the food characteristics that are acceptable to consumers. ISO defines food quality as the sum total of product features and properties needed to satisfy the needs of the customer. Food quality and safety management is required to be robust with adequate science inputs and a background of risk analysis and prevention.

Pages: 6

Practically, all food processing operations use raw materials along with water, energy, and some other resources and result in desirable and undesirable products. Desirable products are utilized for food purposes and the undesirable category of products are termed as wastes and effluents and need to be suitably treated before their disposal. This chapter aims to characterize the food processing wastes and effluents and understand the different available methods of treatment/equipment so as to be in a position to apply the technologies under field conditions. When some quantities of liquid and solid wastes are discharged into a water stream, the concentrations of the organic and inorganic ingredients of the wastes keep decreasing downstream mainly due to dilution, oxidation, sedimentation, and microbial degradation. Dissolved air flotation systems are intended to cause the suspended solids in the wastewater to separate out along with the contaminants and move up to the water surface.