eChapters

INTRODUCTION

Food processing as a technological regime is undergoing a revolutionary change in terms of conception, product and process design and energetics. The conventional approach of a food processor is to develop products with a long shelf-life in user friendly packaging systems. Food processors are usually bothered about sensory attributes and microbiological profiles without much emphasis on the fate of heat labile nutritional and nutraceutical components. The changing consumer perception is slowly but steadily leading towards emergence of novel technologies without depending upon conventional thermal processing. A few years before, non-thermal techniques have emerged for food processing and preservation, but these techniques were restricted to framing of fundamentals with regard to the inactivation of vegetative and reproductive bodies of microbes and the deteriorative enzymes.

INTRODUCTION

Packaging is an important aspect in modern life and in fact the word ‘packaging’ developed a literal value indicating presentation of an issue or material in a comprehensive and compact manner. Food packaging has become a revolutionary trend and plays a dominant role in the promotion of marketing of various fresh and processed food products. The reason could be a number of aspects inclusive of protective, legal and aesthetic elements. The industrial revolution in the late 18th century caused major impact on manufacturing process. Without appropriate packaging no food is acceptable and even in the common household food packaging is being practiced in its own way to render food safety and convenience for various culinary operations. Therefore, food packaging needs to be considered as an essential element of food processing and marketing and it is one of the key areas in food technology making rapid strides in research and development.

INTRODUCTION

For thousands of years fermentation processes were largely natural phenomena exclusively identified with food preservation throughout the world. Fermentations can play a significant role in meeting the ever growing food requirements of world population providing benefits in the form of innovative food products with improved nutritional value and food quality along side better safety. Fermentations can be used to address a large variety of food related problems and in the development of processes to meet the demand for food. In the wake of estimations made by international organizations that global food demand and population would increase by two-fold by the year 2050, much emphasis has been placed over the ways and means to increase food production and preservation.

INTRODUCTION

Fruits and vegetables are historically important constituents of human diet and the growing awareness of consumers about the beneficial effects of these commodities could result in enhancement of global trade involving fresh and processed fruits and vegetables. Emergence of postharvest handling of fresh fruits and vegetables facilitated global trade of these commodities. The developed countries started realizing the export potential of these commodities by development of adequate value addition in terms of pretreatments, shelf life extension and packaging besides grading and other associated packing house operations. However, the trade concerning fresh fruits and vegetables could never come out completely from problems related to pesticidal residues, spoilage, bulkiness of the commodities involving transportation of inedible portions and excessive packaging costs arising out of bulkiness. The other problems associated with fresh produce include mandatory requirement of specific storage temperatures with refrigeration as the primary means of regulation of metabolic rate.

INTRODUCTION

Now-a-days, food products with maximum health benefits and ease in preparation are gaining popularity globally, the reason being changing awareness level about food and dietary habits. Since ages, a number of methods like cooking, baking, drying etc. have been used to thermally process the food materials. Electrical sources of electromagnetic waves are very promising because of advances in nuclear and hydroelectric power as well as ongoing cost rises in traditional forms of fuel, of which there are only restricted reserves. The heating aids include use of wooden fuel, gaseous fuel, electric energy etc.; but the new era of electromagnetic rays had introduced new horizons of food processing by utilizing it in various unit operations (Sakai and Hanzawa 1994). Though, these radiations are gaining popularity in various walks of life; their destructive impact is much dominating. Hence, one should handle these radiations with utmost care as well as comprehensive understanding of the know-how and control over the process.

INTRODUCTION

Radiation processing is a promising technology for improving hygiene and increasing storage and distribution life of food products. Ionizing radiation can be used to bring about beneficial changes in food stuffs (Urbain 1995) and it has been suggested as a method of ensuring safety of meat products (Patterson and Stevenson 1995). Ionizing radiation interacts with an irradiated material by transferring energy to electrons and ionizing molecules by creating positive and negativities (Moseley 1989).

INTRODUCTION

Preservation of food by drying or chemical means as by alcohol or acid fermentation and that by the use of ice is long recorded in history. With the advancement of science and the knowledge governing various unit operations in food processing, these food preservation techniques employing thermal, radiation, or low temperature or a combination of these have only got further refined as regards their viability and commercial applications. Process foods of different genre and cuisine, which include frozen foods too, are increasingly becoming popular the world over for reasons of quality, safety and year round supply of nutritious foods to cater to different niche segments of human society. Increasing health consciousness is buoying those processed foods which are preserved and stabilized using non-thermal technologies as these ensure retention of food nutrients to a better definition. Interest in frozen food also stems from need to deliver safe and nutritious foods with extended shelf-lives.

INTRODUCTION

Drying or dehydration is defined as the removal of moisture from its initial level to a level which renders food materials safe for subsequent storage. It is a simultaneous heat and mass transfer operation in which heat is supplied externally to evaporate moisture and air is forced through the bed to carry away the moisture. Drying is the oldest technique to preserve food materials. Advantages of drying include reduction in water activity, enhancement of shelf life, maintenance of flavor and nutritive value, and reduction in packaging and transportation costs. When the water activity of the dried product is reduced to below 0.6, most microorganisms do not grow and the rates of other deteriorative reactions are substantially reduced.

INTRODUCTION

A mixture is a combination of two or more elements or compounds in any proportion so that the components do not lose their identity. Most materials in our world are mixtures and very few materials are pure substances. Foods are complex mixtures of compounds and the extraction or separation of food components is fundamental for the preparation of ingredients to be used in other processes. Separations usually aim to remove specific components in order to increase the added value of the products, which may be the extracted component, the residue or both. Purposes include cleaning, sorting and grading operations, extraction and purification of fractions such as sugar solutions or vegetable oils, recovery of valuable components such as enzymes or flavour compounds, or removal of undesirable components such as microorganisms, agricultural residues or radionuclides. For example, cooking oils from oilseeds or gelatin from connective tissue; or for retrieval of high value compounds, such as enzymes (e.g. papain from papaya for meat tenderisation or rennet from calf stomachs for cheese making). Other types of separation methods are used to sort foods by separating them into classes based on size, colour or shape and to clean them by separating contaminating materials.

INTRODUCTION

Food is the basic need of human beings. It gets spoiled primarily due to microorganisms and enzymes. Energy is required for microbial growth and enzymatic reactions. At low temperature, the rate of biochemical reactions is slow resulting in prolonged storage life of food. It must have been observed long back that food could be stored for longer period without deterioration during the winter months. Since then this principle is being used to extend the storage life of foods. A sea change can be observed in development of low temperature preservation technology. It has travelled a long journey to reach this stage; however, a major break through took place in twentieth century. Low temperature technology is of two types; refrigeration and freezing. In refrigeration storage, water is in liquid phase and temperature is maintained above freezing point. In freezing technology, the food is stored below freezing point and water gets converted into ice. The former is short term preservation due to slow growth of microbes and lower enzymatic activity while the later is long time preservation due to inactivation of enzymes during blanching and inhibition of microbial activity due to unavailability of free water and much lower temperature. Low temperature preservation is widely accepted and is of commercially important in food supply chain.

INTRODUCTION

The concept of hurdle technology has been developed as a new way to realize safe, stable, nutritious and economical foods. It employs combination of different preservation techniques to achieve a multi-target, mild but reliable preservation of foods. The application of hurdle technology in food preservation is increasing rapidly worldwide. Over the years, insight into the hurdle effect has been broadened and the application of hurdle technology has been extended. A better understanding of the occurrence and interaction of food preservative factors (hurdles) in foods is the basis for improvements in food preservation. If the hurdles for the microbes are known, the microbiological stability and safety of this food might be optimized by changing the intensity or quality of these hurdles. Using the proper combination of hurdles, it is possible to improve not only the microbial stability and safety but also the sensory and nutritive quality as well as the economical aspects of food. The hurdle concept is also referred to as food preservation by combined methods, combined process, combination preservation or combination processing techniques. The hurdle effect is of fundamental importance for the preservation of foods. The illustration of hurdle effect was first introduced by Leistner in 1978. Based on the understanding of hurdle effects, the concept of hurdle technology was derived (Leistner 1985).

INTRODUCTION

By the turn of the century, consumers have been more demanding, sophisticated and discretionary. They want much safer, higher quality, and more convenient to foods. The food processor need to get the best from their existing processing technology in addition to looking for newer ones. New and alternative food processing methods and/or novel combinations of existing methods are continually being investigated by the industry in pursuit of producing better quality foods more economically. Thermal processing is one of the most important food preservation techniques that was first introduced at the beginning of 1800 and has evolved itself in to one of the most scientific mature food processing techniques of recent times. Both science and technology have gone through tremendous transformation in the last two centuries and today it is the most reliable method to assure food safety and stability. Developments in thermal processing and evolution of non-thermal processing technologies like high pressure processing, pulsed electric field, pulsed light etc. have enhanced the utility of thermal processing principles and increased the awareness of possible alternative processing technologies.

INTRODUCTION

Food processing is necessary for the conversion of raw food products in to finished products with desired textural, sensory and nutritional attributes. This is required to be done mainly due to seasonal production and facilitating non-seasonal availability of different commodities. Stages of processing are primary and secondary. In primary processing raw material is converted into food commodities, while in secondary processing commodities are converted into edible products. Processing is mainly done to convert the products into edible forms, to extend shelf life, availability, accessibility and also to provide variety into the form of value added products. Processing of products destroys inhibitors, microorganisms, retards physico-chemical and biochemical deterioration, maintains good sensory properties, preserves and enhances the nutritive value. Unit operations involve phase changes and sometimes chemical reactions also, which are undesirable as they cause inferior quality of the product (Gekas 1992). Different processes like separation, assembly, preservation and packaging are broader classification for unit operations in food processing (Saravacos and Kostaropoulos 2002).

Food Science is one of the ancient sciences and the genesis originates to the very beginning of human civilization. The advent of food science was associated with practice and observation by humans before establishment of scientific concepts. The ancient man knew that roasting or smoking of meat improves the edible quality and digestibility. As a consequence, he started practicing the same much before the reasons for the same could be established. Many of the modern preservation concepts had their origin in prehistoric period itself as humans could use techniques such as dehydration, fermentation and pickling to their advantage to improve the sensory attributes of the products and also to enhance their shelf life. Humans during the Pre-Neolithic period about 2,50,000 years before used fire for cooking meat. During the Paleolithic period humans not only roasted food but also developed grinding, pounding and drying. During the Mesolithic era, humans were desperate for food and got involved in extensive hunting and fishing. During the same time domestication of animals took place and animal husbandry became a reality (Stewart and Amerine 1982). The Neolithic period made qualitative changes in the food habits of humans and they changed from a food gathering and hunting society to one of food production (Heizer and Elsasser 1980).

Over the past several years, there has been significant change in consumer perception on quality and food safety. Consumers are demanding healthy, nutritious and cost-effective products processed under controlled hygienic conditions. Food safety concern, in recent years, has become dominant and important. The requirement of food safety and quality assurance has never been so demanding as it is now. Globally food safety is being addressed independent of food quality. In anticipation of consumer demands on food safety, food sanitary standards at national and international levels are under constant review. Several inter governmental agencies/organizations are engaged in work related to quality assurance and food safety. Amongst these World Health Organization (WHO) and Codex Alimentarius Commission (CAC) play the major role in protecting public health and defining standards of quality and safety aspects of foods for regional and or world wide usage.

Introduction

The economic choice of any process is the criterion for efficient utilization of the by-product that is produced along side of main product. During manufacture of major dairy products, the dairy industry also ends up in producing different by-products. Various by-products of dairy industry are skim milk, butter milk , whey and ghee residue. Dairy industry is particularly confronted with the problem of economic utilization of whey and ghee residue. The techno-economical problems associated with utilization of these by-products, is now receiving considerable attention. More efficient, cost effective and sophisticated technologies have opened up new vistas for manufacture of number of derived by-products. Further more the market for dairy by-products, as an ingredients in other consumer food products like snacks, ready meals and microwavable food products, has been growing.

Introduction

In the recent past there has been a great deal of questioning regarding role of milk fat in cholesterol metabolism and other body functions. The enormous wave against cholesterol containing foods has damaged the image and market growth of fat rich dairy products. This trend is due to presence of saturated fats and cholesterol that are known to increase the incidence of coronary heart diseases one of the common cause of heart attack. The educated and urban society is more health conscious about the presence of cholesterol in their diets. This has led to the greater demand of cholesterol free foods. Ghee being a saturated fat and containing little amount of cholesterol, is suspected to contribute towards coronary heart diseases. However, critically surveyed scientific literature indicates that there is no evidence of any association of milk fat with increased risk of coronary heart diseases. Age old and proven Ayurvedic system of medicine has proved the usage of ghee to induce several beneficial effects on human health and used extensively for therapeutic purpose like in treatment of skin allergy, respiratory diseases, curative for ulcers and eye diseases. This suggest that ghee is a valuable form of dietary fat.

Introduction
Ghee is the pure clarified butter fat prepared chiefly from cream and/or desi butter (Makhan) to which no colouring matter is added.  Ghee manufacture has great significance and relevance to Indian masses and the dairy industry. Ghee is a very popular product since ancient time and has greater demand during festival and other ceremonial functions where use of ghee in food has been considered to delicacy due to its pleasing flavour and aroma. There are sufficient recorded evidence to prove that the manufacture of ghee originated from India and has been used extensively for religious and dietary purposes since Vedic times. Presently about 28% of total milk production is utilized for manufacture of about 1 million tones of ghee per annum. It is the traditional product with an established market. Cow ghee is golden yellow in colour, and is attributed unique therapeutic value.  The colour of buffalo ghee is greenish yellow due to presence of pigments called billirubin and billiverdin. Ghee is characterized by its pleasant, cooked and rich flavour. The preferred texture is of larger uniform size from grains having non-greasy consistency.

Introduction

The demand for butter as table spread has declined due to high cost, poor spreadability at low temperature, high saturated fat and cholesterol content, changing life style and increased demand for healthy products. Today food industry is actively involved in new product development, this includes new formulations and imitation of foods being designed to compete with or replace existing products based on their superiority in convenience, cost and quality. The wide acceptance of bread in regular diet among urban consumers (75 percent of all household) reflects around 8 percent rate of growth in bread consumption. With this increase, the requirement of a suitable spread to complement has also increased. Table spreads include a variety of spreadable semi-solid products such as fat spreads, cheese spread, peanut butter etc. Butter has also been blended with vegetable oils/fat to produce a product that retains dairy qualities of butter with enhanced spreadability.

Butter is one of the leading milk product in developed countries of the world. It serves as a balance wheel of dairy industry. Surplus milk is generally converted into butter to be used during the times of scarcity. It is an article of commerce and a sign if wealth. Butter is a fat concentrate, which is obtained by churning cream, gathering the fat into a compact mass and then working it for proper distribution of moisture and salt. The art of butter making has a long history. The manufacture of butter was confined to colder regions where gravity creaming was successful. The milk was allowed to stand undisturbed for 10-12 hours until layer of cream collects at the top.

Introduction
Makkhan (Makhan) is an indigenous(desi) butter obtained by hand churning of dahi using wooden beater (mathani). It is traditional unsalted butter characterized by its delectable and rich flavour. It is white in colour with slightly greenish tinge and has typical soft body and a smooth grainy texture with pleasant aroma. This product has been extensively used for dietary and religious practices since vedic times. The entire quantity produced forms an intermediate product for preparation of ghee (clarified butter fat). Nearly 30% of the total milk production goes for desi butter manufacture. The average yield of the product is very low ranging from 5.5-7.0% for every 100 kg milk used for the purpose. The chemical composition of the product is variable depending upon the method of manufacture. It is difficult to achieve the uniform standard of 20% moisture in the final product due to limitations in the technique adopted for its manufacture. The non fatty solids and lactic acid are derived from the method of preparation and preservation. Higher non fatty solids in makhan indicates use of self soured milk, while a high lactic acid content indicates prolonged storage and in sanitary conditions of manufacture.

Definition

It is one of the important portion of milk which forms a fatty layer on top of milk when left un-disturbed. It is a prime component of milk and comprises mainly of milk fat. It may be defined as “that portion of milk which is rich in milk fat” meaning portion of milk into which larger portion of milk fat has been gathered.  According to FSSAI, 2011 Malai and Cream are defined as –

Malai means the product rich in butter fat prepared by boiling and cooling cow or buffalo milk or a combination thereof. It shall contain not less than 25.0 per cent milk fat.

Several centuries ago, perhaps as early as 6000-8000 BC, ancient man learned to domesticate species of animals for obtaining milk for their consumption. These included cows, buffaloes, sheep, goats, and camels, all of which are still used in various parts of the world for the production of milk for human use. The significance of milk as the most wholesome single food available in nature has never been debated. It is as ancient as mankind itself. The role and consumption pattern of milk in the traditional diet varies widely in different regions of the world. The tropical countries have not been traditional milk consumers, whereas in Europe (especially Scandinavia) and North America, milk and milk products have been traditional parts of the diet.

Introduction

Maize (Zea mays, or corn as it is known in some countries) is the principal cereal crop in tropical and subtropical regions throughout the world. The increasing use of maize as a staple food reflected the much higher yields per hectare, compared with wheat, rye and barley. Because maize was cheap, it became the dominant food and main source of dietary energy and protein for poor people, particularly those in rural and underprivileged segments of society. Maize is considered to be a native of the Americans. There are different views about the introduction of maize in India. One view is that maize was introduced into India by the Portuguese during the seventh century. Other view is that maize was introduced in Pre-Colombian era through the Atlantic Arabian trade route. This is supported by the more recent variability that has been observed in the maize collections made from the north eastern Himalayan region. However, the historic records regarding the cultivation of maize in India date back only to the Maratha Empire.

Introduction

Rice is grown in more than 100 countries in the world and is an important crop for nutritional security of large part of the population. World rice production in 2007 was approximately 645 million tones. Around 50 countries have an annual production of more than 1 million tones. Ninety percent of the total rice is produced in Asian countries, with two countries, China and India, growing more than half the total crop. Top ten rice producing countries are China, India, Indonesia, Bangladesh, Vietnam, Thailand, Myanmar, Japan, Philippines, and Brazil. In Bangladesh, Cambodia, Indonesia, Lao PDR, Myanmar, Thailand, and Vietnam, rice provides 50-80% of the total calories consumed. Major part of the rice is consumed locally where produced and only 6-7% of world rice production is traded internationally.

Introduction

Barley is an important cereal crop grown all over the world and is used mainly for feed and malt purposes and little for human food. Barley is the world’s oldest grain, as evidenced by discoveries in ancient cities in the Middle East and North Africa. It has been cultivated for about 8,000 years, and today is the world’s fourth largest cereal crop. Considerable evidence is available that points to the role of barley as sustaining food source in the evolution of humans. Additionally, alcoholic beverages of various types and fermented foods prepared from barley are commonly referred to in the ancient literature. As other food crops (wheat, rice, corn and rye) became more abundant, barley was relegated to the status of “poor man’s bread”. In the United states, barley used as food is 1.5%, as animal feed 65% and in malt and alcohol production 30% (Newman and Newman, 2006). In 1991, barley used as food in European countries was even lower (0.3%) than the United States. In contrast, during the same time period food was the largest for barley in Morocco (61%), China (62%), India (73%), and Ethiopia (79%). However, current consumer interest in nutrition and human health may help restore barley’s status in the human diet. Nutritional qualities of barley have been known since ancient times. For example, Ajgaonkar 1972 described how ancient Indian physicians effectively stabilized type II diabetics some 2400 years ago. Treatment was remarkable simple and not really different from recommendations that are given to diabetic patients today, i.e., lose weight, change diet, and increase exercise.

Introduction

Improvement of wheat grain quality depends on the knowledge of quality requirements of different end-use products and the genetic components controlling different quality traits. In previous chapters we have dealt in-depth with quality requirements of different end-use products and their genetic components. Depending upon the goal of quality improvement, different strategies are adopted to improve wheat quality. It depends upon the number of genes controlling the traits as well as the availability of the simple methods for phenotyping the traits especially during early segregating generations. In addition stability analysis of the traits across the environments is essential before we go for breeding. Constraints in time, cost, and sample availability usually necessitate the use of predictive tests during early generations, followed by milling and baking tests on advanced lines that have met a number of agronomic, disease and predictive quality criteria. Knowledge of germplasm lines having specific quality traits is needed to initiate breeding for the improvement of wheat grain quality for different end-use products. The quality requirements of different major end-use products are provided in the following table (Table 1).

Introduction

Nutritional value of food stuff is defined by its ability to provide nutrients required by the body. Proteins, carbohydrates, fats, minerals and vitamins are main ingredients in food stuffs. Wheat is an important source of these nutrients. The distribution of nutrients within wheat kernel is typical of many cereals. Nutrients are generally found in the highest concentrations in the germ or embryo and in the aleurone cells surrounding the starchy endosperm followed by bran, whole wheat flour and white flour in decreasing order. Of special importance is that it contains the entire B complex, except for vitamin B12. B vitamins function as cofactors in many metabolic reactions involved in the release of energy. The germ, which includes the scutellum, is especially rich in vitamins B and E, high quality protein, unsaturated fats, minerals, and carbohydrates. The bran consists mostly of the insoluble carbohydrate cellulose, and contains incomplete protein, traces of B vitamins, and minerals including zinc and iron. The endosperm is the largest part of the grain, and consists mostly of the carbohydrate starch, incomplete protein, and trace amounts of vitamins and minerals. Significant variations in the content of grains occur because of variety, crop year, area, fertilizer, and soil type.

Introduction

Carbohydrates constitute nearly 80% of the total dry matter of wheat kernel. Starch is the predominant form, with cellulose, hemicellulose and pentosans present in lesser amount. Starch is present in discrete granules within the cells of the endosperm. Starch content is available in the range of 65% to 75% and generally related negatively to the protein content. Starch structure is a crucial determinant of many end-product uses of wheat. While the amylose /amylopectin ratio is a useful descriptor of starch structure, a more complete analysis of the population of the molecules which constitute a particular starch is considerably more revealing. The molecules range from the high degree of polymerization (10⁷ – 109 glucose units) and heavily branched amylopectin population, to the lower degree of polymerization (103 -106 glucose units), and infrequently branched amylopectin population. Starches with widely differing structures are suited to particular end uses. For example, starches with no amylose, the so called waxy starches are particularly suited to use as thickeners or gel forming agents because they form a clear stable gel with little retrogradation. In contrast, starch with high amylose content form hydrogen bonded insoluble aggregations which are suited to use in adhesives, plastics and as a source of dietary-fibre starch. The size and branching pattern of starch are also important determinants of the suitability of starches for particular end-uses due to the effects these parameters have on gelatinization temperature, starch swelling and viscosity.

Introduction

Bread wheat (Triticum aestivum L.) is one of the most widely cultivated and consumed crops in the world. Wheat is perhaps best known for its different end-use baking properties as determined by grain texture, protein content and quality. Wheat is generally traded by and classified into “hard” and “soft” market classes on the basis of grain hardness or texture of the wheat kernel (caryopsis). Soft wheats have softer endosperm texture that fractures easily, therefore requiring less energy to mill, yields smaller particles, and has less starch damage after milling when compared to hard wheats. Hard and soft are used with slightly different connotations in different parts of the world. In Western Europe, hard is applied primarily to durum wheats and the soft applied to bread wheat. Elsewhere the term is applied to different cultivars within the species Triticum aestivum. In general, hard wheats are used for bread baking, while soft wheats are used for cookies and cake making. Hard wheat requires more force to crack the kernel, maintains a larger particle size, passes through sieves more easily and has more damaged starch MacRitchie (1980). Higher starch damage is required for good bread making quality Tipples et al. (1994) but is detrimental to the biscuit making quality.

Introduction

Wheat is the most important cereal crop to the human kind. It is the main source of energy and nutrition in human diet. Wheat is consumed in the form of large number of end products as chapati, bread, biscuit, cakes, pretzels, noodles and pasta products. Millions of people are involved in milling, baking and pasta products industry with huge turnover per annum. However, each end-use product of wheat has it’s own specific requirement for example basically hard wheats along with strong gluten and high protein content are used for bead making. Soft wheat with weak gluten and low protein content are required for biscuit making Souza et al. (1994). Durum (tetraploid) wheat is used for pasta products as macaroni, vermicelli and spheghatti and Dicoccum for therapeautic purposes. Often chemical improvers are used to improve the dough properties for these products. Most of these chemicals have been banned because of their toxic effects. Therefore, only alternative is to develop varieties suited to meet the requirements of these end-use products. This needs better understanding of molecular basis of grain quality to accelerate breeding for producing wheat varieties for each end-use product separately. Storage proteins are the major component of grain which determines end-product quality. In this chapter detailed structure, genetics and functionality of gluten proteins are described.

Introduction

Dough is a complex mixture of flour constituents, water, salt and other ingredients depending upon the requirements of end-products. It is the principal intermediate stage in the transformation of wheat into different end-use products. Rheological properties of dough determine the behaviour of dough during mixing, rounding and molding used in making different products and also effect on the quality of finished product. Therefore, understanding the various features of dough rheology and their relations with product quality is important. The importance is enhanced further because of mechanization and automation of baking industry. Dough is composed of continuous phase in which gas cells are dispersed. The continuous phase is called “dough phase”. It consists of starch granules embedded in protein matrix along with some lipids, cell remnants and yeast cells in fermented dough. Gas production and retention is the most comprehensive quality requirements of the dough for bread making. The ability of the wheat dough to retain gas during fermentation and oven rise is unique. This depends on the ability of the dough to be stretched into thin membranes because of protein phase.

Introduction

Durum or macaroni wheat (T. turgidum var. durum) is an important crop used chiefly for the production of pasta in Western Europe and North America, and two layered bread, single layered bread, burghul, couscous, pasta, frek and feed in other parts of the world (Table 1). In North Africa and the Middle East, durum is also used for producing flat breads. On a global basis only a small amount of durum wheat is used for baking of pan-style and hearth-style bread. Also, durum wheat for baking is often used in blends with common wheat. In India, durum occupies approximately 2.0 mha area and production is estimated to be around 2.5-3.0 million tones annually amounting to 3-4% of the total wheat production. The consumption of pasta is increasing at the rate of around 5% annually and currently it is estimated to be around 10 Lakh tones. The demand for pasta products may increase further due to increasing population and improving standard of living.

Introduction

For many years it has been an elusive task to provide a precise definition as to what constitutes quality in wheat. Each country has its own traditions in bread and other bakery products. Quality will mean different things to a miller, a baker, a grain handler or a plant breeder. As the baking industry becomes increasingly specialized, specific qualities are sought. Even among those wheat varieties generally recognized as having desirable quality traits, the influence of environment can be substantial, and this necessitates a high level of skill on the part of grain buyers to survey the current year’s crop and blend the wheat for a specific end-use. This genotype X environment effect on quality also limits the capacity of end-users to source identity-preserved wheat from a narrow geographic area. Those of us engaged in the field of plant breeding are concerned primarily with those traits that can be manipulated genetically, and we study their stability under a range of climatic conditions. Constraints in time, cost, and sample availability usually necessitate the use of predictive tests during early generations, followed by milling and baking tests on advanced lines that have met a number of agronomic, disease and predictive quality criteria.

Introduction

There are large numbers of wheat based products such as fermented pan bread, flat breads including chapati, biscuits, noodles and pasta products. Each product has its own specific requirements. For example fermented pan bread needs wheat with higher protein content, stronger and extensible gluten. Chapati requires hard wheat with high protein content and medium gluten strength. Waxy wheats have been found associated with improved shelf life of breads. White salted Japanese noodles need partial waxy wheats with soft grain characteristics and medium protein content and gluten strength. Partial waxy wheats with comparatively lower amylose content and higher starch paste viscosity improve texture of white salted noodles. Yellow alkaline noodles need comparatively harder wheat with medium strong gluten and without waxy trait. Pasta made from durum wheats requires stronger gluten, high protein content and higher content of yellow pigments. In this chapter detailed account of both fermented and flat breads will be given.

Introduction

Wheat is an important cereal crop and is widely cultivated across the world. Wheat is consumed in different forms and major products are chapati, bread, biscuit, noodles and pasta products. Wheat has three groups of cultivated species namely bread, durum and dicoccum wheats. The common or bread wheats account for approximately 95% of world production. Nearly all of the remaining 5% cultivated varieties are durum wheats used for pasta products and couscous and dicoccums represent very little of the total wheat production. The bread wheat is divided into two broad classes based on grain texture; hard and soft. Hard wheats with high protein content and strong gluten are used for making bread and some noodles while soft wheats with lower protein content and weak gluten for biscuit, cakes and pretzels. Semi-hard wheats having some combinations of the above characteristics are utilized for making unleavened breads such as chapati, Asian steamed bread and some noodles. There can be large disparity within wheats of various classes; therefore to provide consistent quality, it is divided into grades. The grading is determined by the test weight, protein content, moisture and foreign material. The major wheat exporting countries have distinct grading patterns designed to provide wheat for specific purposes and consistent quality.