eChapters

India is bestowed with diverse agroclimatic zones which aids in the cultivation of large number of commercial flowers like rose, gladiolus, chrysanthemum, tuberose, jasmine, marigolds, orchids, lavender, lily, anthurium, gerbera, potted plants, cut foliages, bedding plants etc. In floriculture trade, value addition takes place at every step to create a novel product and to cater the demand of heterogeneous consumers. In the international floriculture trade, besides floriculture and pot plants, many other value added products include artificial colouring of the flowers to create novelty, aqua-packing for better presentation and attraction, three dimensional window packing of flowers for greater visibility, garland, venis, bouquets, flower arrangements etc.

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

Food being the basic need of all humans and other living organisms, the production and processing of food is a continuous activity with several new procedures and technologies adoption; thereby the quality of food needs an emphasis which also protects the consumers by providing safe and suitable food. The contaminated foods, food borne illness outbreaks though at times referred to poor consumer handling, commitment for provision of safe food to consumers is also a Governments concern. In the recent years, food safety measures through Food Safety programmes and increase in awareness are being followed. The food production in our country is the most promising sector which is the cause for white revolution and green revolution. India ranks first in the world in production of cereals and milk and second largest producers of fruits and vegetables. India stands second in inland fish production. It is second largest exporter of rice and so on. Food processing sector has a great potential which covers a wide spectrum of products encompassing agriculture, horticulture, plantation, animal husbandry and fisheries. But the growth of food processing industries in our country is rather slow. However, to encourage, the government is providing lot of incentives in the recent years.

INTRODUCTION

A food may have three attributes (1) Provide energy and nutrition (2) Give pleasure, i.e., enjoyable aroma, colour, and taste and (3) Health benefits. Functional food has physiological benefits and reduces the risk of chronic disease beyond basic nutrition.

Functional foods, also reported as ‘nutraceuticals’, ‘medical foods’ or ‘designer foods’ in the literature, were first described by Roberfroid (1999) as ‘Food similar in appearance to conventional food that is intended to be consumed as part of a normal diet, but has been modified to subserve physiological roles beyond the provision of simple nutrient requirements’. Examples are iodized salts, vitamin A and vitamin D fortified milk and yoghurt, folic acid enriched bread, soy products, wheat bran and oats products.

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

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).

Thiamann (1948) designated the plant hormones by the term ‘phytohormones’ in order to distinguish them from animal hormones. He defined a phytohormone as “an organic compound produced naturally in higher plants, controlling growth or other phy-siological functions at a site remote from its place of production and active in minute amounts.”

According to Johannes van Over-beek (1950), the plant hormones are defined as “organic compounds which regulate plant physiological process – regardless of whether these compounds are naturally occurring and/or synthetic; simulating and/or inhibitory; local activators or substances which act at a distance from the place where they are formed.”

An anti-nutritional factor is a substance which, when present in human or animal foods, reduces growth. Examples are phytate, protease inhibitors (notably soybean trypsin inhibitor) and excessive dietary fiber.

Anti-Nutritional Factors

    ·    Protease inhibitors inhibit the activity of trypsin, chemotropism and other proteases. They are found in legumes such as beans and peas, but also in cereals, potatoes, and other products. Their presence results in impaired growth and poor food utilization.

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. Polyphenols are a structural class of mainly natural, but also synthetic, and semisynthetic, organic chemicals characterized by the presence of large multiples of phenol structural units. The number and characteristics of these phenol structural underlie the unique physical, chemical, and biological (metabolic, toxic, therapeutic, etc.) properties of particular members of the class. The term polyphenol derives from poly-, from the ancient Greek word (polus, meaning “many, much”) and the word phenol which refers to a chemical structure/substructure formed by attaching to an aromatic phenyl or benzenoid ring an alcohol-type hydroxyl (-OH) group (giving rise to the “-ol” suffix). The term “polyphenol” has been in use since 1894.

The pigments are energy-rich organic compounds. The potential chemical energy of these compounds comes from the light energy. The light enrgy to be effective in photosynthesis must be absorbed by a suitable pigment. This vital role is performed by a suitable pigment. This vital role is performed by the green pigment. Chlorophyll, carotenoid (carotenes and xanthophylls), anthocynin and phycibilins.

Franz Holfmeister’s (LT, 1850-1922) definition, “vitamins are substances which are indispensable for the growth and maintenance of the animal organism, which occur both in animal and plants and are present in only small amounts in food”, still holds good, although it has been interpreted in various ways.

The term enzyme was coined in 1878 by Friedrich Wilhelm Kuhne to designate these biological catalysts that had previou-sly been called ferments. As they quicken most of the chemical reactions occurr-ing in the body, the enzymes have been designated as the “manifestations of nature’s impatience”.

Nucleic acids like proteins occur in all living cells. They device their name because of their primary occurrence in the nucleus and acidic nature. Deoxyribose nucleic acid (DNA), one of the two nucleic acids is a major component of chromosomes. Small amounts of DNA are also found associated with chloroplasts and mitochondria.

Lipids are a hetrogenous group of substances, widely distributed throughout the plant and animal kingdom. In plants they are present in the seeds nuts and fruits, while in the animals they are stored in adipose tissues, bone marrow and nervous tissues. Lipids are relatively insoluble in water and readily soluble in organic solvents such as ether, chloroform, carbon disulfide, benzene, hot alcohol etc. The term lipid was used by the German biochemist Bloor in 1943 for a major class of tissue components and foodstuffs.

Amino acids are essential components of all living cells as building blocks of proteins. They are also metabolically active and supply substrates for many other biochemical reactions. In a bacterial cell, about 0.4% of the dry weight is amino acids. The amino units in other living systems varies according to species, age and part of the body.

Carbohydrates are synthesized from CO₂ and H₂O in chlorophyll containing plants during photosynthesis. The term carbohydrate was originally coined for this class of compounds as most of them were hydrates of carbon or could be represented by the general formula C_n(H₂O)n. Not all the carbohydrates however, have this empirical formula, for example deoxyribose (C₅H₁₀O₄) and glucosamine (C₆H₁₃O₅N). Further lactic acid (C₃H₆O₃) formaldehyde (HCHO or CH₂O) and acetic acid (CH₃­.COOH or C₂H₄O₂) with this general formula is not a carbohydrate. Carbohydrates are defined as the compounds having either an aldehyde or a ketone group or a modified aldehyde or ketone group and other carbon atoms with alcoholic (-OH) group. Hence the continued usage of the term carbohydrate is for convenience rather than exactness.

Hypothesis become theories and theories attain rank of laws after withstanding rigorous experimental tests. Feasibility of a process is confirmed in the laboratory. Qualitative and quantitative analyses give complete chemical picture of the substance. It is with these considerations in mind we proceed to learn what is there in a laboratory.

Preserving plant materials in a dried form is not a new idea. It has been considered as an art for hundreds of years. Fragrant dried herbs were placed in Egyptian pyramids. Dry flower arrangements have been popular in Europe for several centuries. During 1700 A.D, the early American settlers used dry flowers to brighten their homes. Any plant material can be preserved for use as dry flowers (Al Pertuit, 2004). Though enormous work is being done in this field, most of the literature is published by horticulture amateurs. Scientific work in this area is less. However, a review of the research work done in dry flower technology is discussed in detail.

Driftwood is wood that has been washed onto a shore or beach of a sea or river by the action of winds, tides, waves or man. It is a form of marine debris or tide wrack.

In some waterfront areas, driftwood is a major nuisance. However, the driftwood provides shelter and food for birds, fish and other aquatic species as it floats in the ocean. Gribbles, shipworm sand bacteria decompose the wood and gradually turn it into nutrients that are reintroduced to the food web. Sometimes, the partially decomposed wood washes ashore, where it also shelters birds, plants, and other species. Driftwood can become the foundation for sand dunes.

23.1 Dry Flower Packing

Careful packing is one of the most important aspects of any product. Dry flower packing is the simplest way to capture the essence of summer flowers till long. Dry flowers should be packed nicely to avoid any damage. They should be packed alone in appropriate sized carton loosely cushioned with paper.They should be packed in a manner to keep them away from direct sunlight leaving some room for air. Packing material should be stable and firm to hold the dry flowers well without any damage during storage or transportation. Dry flowers can be packed in a variety of ways: in poly bags, window box, cardboard box, or in a sachet.

Dry Flower Products

Dry flowers are aesthetically beautiful and they enhance the décor and liveliness of any room. They bring the fiery warmth and bounty of the season into the home with ease every fall. Much of fall’s beauty lies in the glorious changing colors of autumn leaves. These flowers are dried to use them in a wide range of products. Dried floral products are widely used for decoration and for adding zest to a room. Apart from that they are also used as an essential component of many products. They are widely used to make handmade paper, lampshades, candle holders, jute bags, photo frames, boxes, books, wall quilts, topiary, cards and several gifts. The use of dry flowers in the making of these products enhances the appearance and beauty of these products. They look sophisticated when gifted to someone or used as a décor of your own home.

Introduction

Floral arrangement is the art of selecting and organizing flowers and foliage according to the elements and principles of design in order to attain a pleasing and interesting design. Arranging flowers is an artistic activity and a way to express oneself creatively.

21.1 Flowers and Foliage

Successful floral arrangement begins with plant materials that have been properly handled and prepared. Beauty and good composition of an arrangement is not determined by the cost or rarity of plant materials used, but by the way they are selected, cared for and arranged. The plant material has to be handled carefully, handling only the stems. Properly dried, bleached and dyed flowers, foliage and accessories can be arranged following the principles for dry flower arrangement.

Artificial flowers are a great source of handmade decorations. Beautiful handmade artificial flowers are suitable for banquets, weddings or to decorate any room in the home. They are generally made of paper or cloth and in a variety of colors. They come in either a bouquet form or can be ordered as individual stems. There are different kinds of artificial flowers including silk flower, latex flower, flowers made from natural leaves and embroidery flower.

Dried Fruits and Pods

The enchanting beauty and usage of fresh pods or fruits need not end up with the season. They are dried and preserved for years. A colorful array of choice dried fruits are very popular in dried arrangements. There are numerous dried fruits and pods used in potpourri and dried flower arrangements.

Dried Petals

Many types of dried petals are used for making pot pourii eg., land lotus petals, rose petals, mahogany petals, lily petals and lotus petals. Flowers are dried for everlasting beauty. They add an elegant touch to the room and are dried for everlasting beauty. Preserving blooms is a wonderful way to preserve memories and enjoy long lasting splashes of color. Many flower parts are used in dried form. A vibrant and thrilling range of dried petals are used to embellish greeting cards, folders, books, and other personal belongings.

Dried Leaves

Leaves are dried or preserved to capture the beauty of spring and hold it for a long time. Dried leaves are beautiful when used in any decoration. There are several preserving techniques that help to enhance the prized collection of leaves well. Drying leaves is an age old tradition. Leaves were dried to preserve them. The leaves were picked for their medicinal qualities, fragrance, or to be used as spices and for their decorative value. Leaves can be preserved by various ways: 

Dried Grasses

Grasses are easy to collect to dry and use. When the seed-heads have formed, the grass is cut off just above the soil using a sharp knife. They are allowed to lie in a thin layer in the sun for a day or two, turning them over a few times. They should not be allowed to get too damp. After they are dried they are put into a plethora of uses. Bunches of dried grasses can make a wonderful addition to any home or office.

Perennial Flowers

Perennial flowers have a life span of more than one year and usually bloom during a specific time period every year during the growing season. These flowers are hardy and herbaceous. They need less maintenance, less water, and fewer pesticides than annuals. Perennials are easily used as ground covers, mixed with annuals, grown in containers and used as accents or specimen plants. Many perennials are short bloomers and are best mixed with others that bloom at different times or included with other landscape plants. These flowers are treasured by gardeners as heirloom plants and have proven themselves to be hardy enough to withstand weather and climate extremes. They are treasured in their dried form for beautiful and exotic dried flower arrangements.

Flowers blooming in a garden can be preserved by drying them for use in arrangements, decorations and various other applications. Natural dry flowers can be annual or perennial. Some of the important annuals used for dry flower making are described below.

14.1 Annual Flowers

Plants classified as annuals are those that complete their life cycle within the space of one year. Annual flowers are versatile and sturdy. The annuals have many uses in landscaping. Annual flowers are beautiful and garden lovers tend to preserve these flowers throughout. They dry these flowers and store them for use in several beautiful dry flower arrangements.

Skeleton Leaves

Skeleton leaves are semi-transparent leaves, also called fossil leaves. They are prepared by soaking the fresh leaves in bleached water and then by hand rubbing the soft green flesh from the network of veins. The leaves can be then dyed to variant colors to give them a beautiful and pleasing appearance. Although delicate by nature, they are actually sturdy and can easily be glued to a variety of surfaces. They come in several colors and sizes to meet a complete line of crafting needs. The delicate beauty of these leaves is sometimes meant to capture life, hope and memories. These delicate, gorgeous skeleton leaves are a perfect accent for all craft projects. They make a beautiful and elegant statement when they adorn your wedding invitations. They work surprisingly well on gift tags, greeting cards, scrapbooks, collages, papermaking, stenciling, and stamping. They are perfect for decorating bridal bouquet, wedding reception table, candles, and wedding favors.

One of the important aspects of dry flowers is the pleasure of gathering flowers and grasses to make wonderful dried arrangements. The only drawback is that the original colors fade and the floral arrangements can end up looking like a bunch of straw. To enhance the colors of dried flowers, dyeing is advocated. While coloring ferns or small leaves, it is better to work on an aluminum foil or waxed paper so it can collect extra paint, which can be used on another leaf. Leaves should be lightly brushed, and never saturated with paint. The painted specimens are placed on the waxed paper or on a computer paper to dry. Newsprint should not be used.

The major drawback of dried arrangements and other dry flower products is that they are dull and lack the brightness of fresh flowers. To overcome this problem, flowers are bleached and dyed. This enhances the visual appeal of the product. Both chemical and natural dyes can be used. Squires (1971) reported on the use of various types of paints to colour dried foliage and flowers using brushes or by dipping and spraying. Enamel paints, interior paints, poster paints and tube paints could be employed for this purpose. Tampion and Reynolds (1971) explained the three ways by which dyeing can be carried out for fresh flowers. They are as follows:

Bleaching is essentially whitening or decolourizing. It is an important step in the processing of dry plants. It involves chemical processes that can change the ability of colour bodies to absorb light by changing their degree of saturation (Robson, 1967). This chemical action removes the discolouration occurring during the dehydration phase of preservation of plants. It allows the effective use of dyes for colouring. Bleaching agent is a material that lightens or whitens a substrate through chemical action. To reduce the processing costs, multistage bleaching is suggested. In this method, both oxidative and reductive bleaching chemicals are used.

The process for freeze dried flowers began in 1989. Freeze drying was first used by the Peruvian Incas of the Andes, who stored their food on the heights of the Andes. The ancient Incas were the first to learn the benefits of sublimation. They discovered that when they dried food at high elevations, the results were better. Even though the food would freeze, it would dry well if left exposed to the sun. The reduced pressure at high elevation, combined with the dry air and energy from the sun, had caused sublimation to occur.

Microwave Oven Drying

Microwave drying is quick and relatively simple. It takes only a few minutes and provides dried flowers that look fresher and more colorful than obtained by other methods. Flowers with thick petals like magnolia are not suitable for drying in microwave. Since flowers vary in moisture content, texture and density, care should be taken to use the same sized flowers from one species at a time. It has been found that many flowers held almost true to life color and form using this process. Brightly colored flowers are best to dry. Flowers such as lilies, roses, violets, zinnias, and dahlias work well with this process.

Drying by Embedding

A desiccant is simply a substance with a high affinity for water which can be used as a drying agent. Embedding the flowers in a granular, desiccating material is probably the most commonly used method and many consider it the best all around method. Several materials are used as drying agents. All the agents used vary in cost and in the results they produce. It is important to use the correct procedure when covering the flowers so that their form is maintained. Most well known is silica gel, but also clean dry sand can be used. Usually an airtight container is used; the flower heads are placed in the drying mixture face up, and very carefully covered with the mixture. The container must be kept closed during the drying process. After 4-14 days, depending on the thickness of the flower, the flower will be dry.

Pressing Flowers

One of the most popular methods for drying flowers is to put them under pressure, to remove the moisture out while leaving the color of the flowers and structure intact. There are several ways to apply pressure to flowers. The easiest method is placing them in heavy books and allow for drying. Flower presses can also be used. Some guidelines for pressing flowers in the traditional way are explained below:

Various methods are employed to dry flowers and foliage. The method adopted for drying depends largely on the character of the plant, that is to say whether the plant is glabrous, succulent or not succulent, hardy or delicate in nature. The suitable method for drying any given plant has to be studied elaborately. However, the different methods of drying are described broadly in this and consequent chapters.

4.1 Dry Flower Garden

Contrary to popular assumptions, the area required for producing large quantity of dried flower material need not also be large. However, the garden should be planned so as to harvest dry flowers all year round by planting evergreens, deciduous plants, annuals and perennials. Rows of flowering plants should be planted in the dry flower garden. Herbs are easy to grow, and can be planted in pots and window boxes. They are useful in transforming simple cooking into gourmet dishes, while also lending their delicate scents to a room when dried and for use in wreaths, pot pourri and arrangements. Gardens for dry flower production should include a wide selection of weeds, grains, seed-heads and pods. Flowers such as hydrangeas, zinnias, roses, dahlias and sunflowers and a selection of line flowers such as golden rods, statice, gladiolus, larkspur and delphinium can also be grown as these will provide a greater variety of flowers needed in flower arrangements.