eChapters

Abstract

Coral reefs, the marine representatives of tropical forests, coupled with the sea grasses contribute considerably to the coastal productivity. Damages to these ecosystems will immediately affect the fishery productivity of the region. Due to this, the long-term ecological impact of the recent tsunami will be a serious set back to the local, national and regional economy than the immediate losses. Andaman and Nicobar reefs represent the second largest coral reef formation next to the Great Barrier Reef and are also comparable to the coral reefs of Indonesia and Philippines in terms of diversity of species and associated floral and faunal components. The recent mega – subduction of the Indian plate below the Burmese micro – plate in Andaman – Sumatra region has not only deepened the southern and uplifted the northern group of Andaman – Nicobar islands but also created a disastrous tsunami on Dec 26, 2004. While such tectonic changes are expected to cause longterm changes in the coral reefs of Andaman, Nicobar group of islands, the tsunami has damaged the coral reefs instantaneously. However, the coral reefs of the Gulf of Mannar and Palk Bay are not much affected by the tsunami by virtue of their geographic position in the shadow region of Sri Lanka.

Keywords: Indian coral reefs, Tsunami effect, Coral recovery

Abstract

Design, operation and optimization of dryers demands the calculation of energy consumption, in most cases in the form of thermal energy, equipment sizing, temperature and moisture distribution of solids as well as temperature and humidity distribution of drying air. Energy calculations are very important as drying is a widespread process in a variety of industries and is highly energy demanding. In the energy analysis of the process the first step is the estimation of the minimum energy requirement followed by the estimation of energy rejection through solids stream and especially through drying air. Increase of thermal efficiency is always willing and the two most common ways for its achievement is the application of heat exchange between cold feeding air and relatively hot rejecting drying air and hot air recirculation. The later is also employed for the adjustment of air temperature and humidity gradient through the dryer. The combination of a heat pump with the dryer decreases considerably the thermal energy consumption but demands electricity and the method can be beneficial in cases of excess electricity production in the process plant, e.g. by cogeneration. Utilization of exhaust hot air from the main drying unit for the predrying of wet solids can also decrease the total energy requirement. The application of humidity adsorption from the feed air increases its drying potential, but regeneration of adsorbent is required. Grand composite curve of the process plant can reveal potential heat sources from different unit operations.

Abstract

The Car Nicobar Island is one of the several islands in Indian Ocean which was severally damaged by the Great tsunami on 26 December 2004. The great tsunami event caused massive devastation, in the form of loss of life and property in south and south East Asia. The objectives of the study are to assess the changes in the coastal features of the Car Nicobar Island using various indicators such as the tsunami height, run- up elevation, water flow direction, erosion, sand deposition and coastal subsidence. Andaman &Nicobar Islands are the summit of the submarine mountain range lying along the great tectonic suture zone extending from Eastern Himalaya to Sumatra and Lesser Sunda via Myanmar border and Arakan hills. The IRS P-6 satellite data has been found to be very useful in the present tsunami assessment studies. The digital analysis of the satellite data was done using the image processing software (ERDAS IMAGINE 8.4) and DTM to quantify the tsunami height (15 m), run up elevation (2-19 m), inundation (295-1203 m) and coastal responses. The settlements and coconut plantations have been severely damaged in the island, which were assessed using GIS analysis of the pre and post-tsunami satellite data.

Keywords: Tsunami, Wave Height, Run-up Elevation, Inundation, Coastal Responses, Remote Sensing, GIS.

Abstract

The seaquake on 26^th December 2004 with its epicenter at Sumatra triggered a tsunami, which had a major impact on South East Asian countries. During that incident, the average height of the tsunami wave was 7-10 m and the penetration of seawater was up to 1-1.5 km. The surface water resources meant for irrigation and other drinking purposes got affected by the ingress of seawater in many areas. The direct environmental impacts of the tsunami have more impact along the entire east coast and caused more damages in coastal systems. The physical and chemical perturbations caused in the coastal zone by the tidal waves are discussed. In order to assess the environmental impact on coastal system, it is suggested that significant physical and biogeochemical factors could be framed to quantify the problems.

Keywords: Tsunami, Physical and Chemical Alterations, Coastal zone.

Abstract

Vitamin C is one of the most important phytochemicals and can be found in almost all fruits and vegetables. Since it covers almost all eventualities, being water solute and prone to leaching from cells, thermally labile (one of the most labile vitamins), pH-, metal ion-, light-sensitive, as well as readily oxidizable by ascorbic acid oxidase, vitamin C is selected as the most frequently measured nutrient to evaluate the nutrients loss during thermal processing. It is generally accepted that if vitamin C is well preserved, the other nutrients are also well retained. Higher retention of vitamin C in processed products is highly desired. Herein this chapter reviews the degradation mechanism and kinetics of vitamin C of fruits and vegetables during thermal processing, such as blanching, drying, cooking and frying. It starts with an overview of the functions of vitamin C in human’s health. Then the current status for understanding of the degradation kinetics of vitamin C during thermal processing was outlined, followed by the discussion of its degradation mechanism. At last, potential strategies or alternatives to keep vitamin C are identified and discussed.

Abstract

Mushrooms are the fruiting bodies of fungi, a group of organism that is different from fruits and vegetables. They are a rich source of good quality protein having more essential amino acids and vitamins with low calories. There are about six commonly known edible mushrooms throughout the world with button mushroom (Agaricus bisporous) being the most familiar and commercially important variety. Mushroom is a highly perishable product with a shelf life limiting to a few days. Soon after harvest, it starts to undergo physiological disorders like shriveling, wilting, liquefaction, browning, textural as well as weight losses and flavour changes. The main responsible factors for the quality deterioration after harvest are respiration rate, browning, bacterial spoilage of mushrooms, temperature and relative humidity. Because of its limited shelf life under ambient conditions of temperature and humidity, the preservation of mushrooms is a matter of concern. Various techniques have been involved in the extension of shelf life of mushrooms including chemical treatments, cooling, modified and controlled atmospheric storage, radiation, drying etc. Drying is one of the most accepted and effective methods for the long term storage of mushrooms. Mushrooms preserved by drying have a pleasant flavour and are used as an important ingredient in several food formulations including salads, instant soups, meats and rice dishes. Various drying processes like sun drying, hot air drying, freeze drying, vacuum drying etc. can be used for the long term storage of mushrooms. As mushrooms are sensitive to temperature, determining the right drying method is the key for the successful and effective operation of the system. The different operating conditions involved in various methods of drying affect product quality considerably. The effect of drying methods on the process and the quality of the dried mushroom is explained in detail in this chapter.

Abstract

Cocoa and coffee are highly sought after commodity crops in the market owing to the distinct flavor and aroma characteristics. Cocoa beans are mostly used in the manufacturing of chocolates and various types of confectioneries while coffee is mainly consumed in the form of beverages. Both cocoa and coffee need to be dried and roasted in order to produce the flavor precursors which further develop into the desired flavor and aroma in the finished products. This chapter aims to provide an overview of cocoa and coffee processing with particular emphasis on drying and roasting aspects and its impact on product quality.

Abstract

Application of ultrasound is one of the most promising uses of novel technologies in food processing. Use of ultrasound at various stages of drying has resulted in significant decrease in drying time and improvement in quality characteristics of dried products. The chapter discusses the principle behind use of ultrasound, general application in food industry with detailed description of various drying processes and equipments assisted by ultrasound.

Abstract

Foam Mat Drying (FMD) is an economical alternative to drum, spray and freeze-drying for the production of food powders. The raw material is converted into stable foam by adding foaming agent through beating or whipping in presence or not of foam stabilizers, and dehydrated by different classical airflow and thermal means. A high-quality food powder attributes can be obtained by the proper selection of foaming method, foaming agents, foam stabilizers, time taken for foaming, suitable drying method and temperature. FMD can be used for large production of food powders because of its suitability for all types of food materials, rapid drying at lower temperature, retention of nutritive value and bioactive compounds, good reconstitution characteristics and flowability and cost-effective for producing powders.

In this chapter, basics of foam and its structure, mechanisms of foaming, types of foaming agents and stabilizers for the production of stable foam have been discussed. The influence of foaming agents, foaming properties, thickness of foam and drying temperature on the drying characteristics of mat are also studied. This chapter analyzes the application of foam drying process for different food materials, the microstructure and whole quality attributes of obtained powder, and the energy consumption and costs of FMD as well.

Abstract

Pulse combustors provide an advantageous superposition of unsteady gas flow and high intensity sound waves. Such a combination does not only accelerate drying rates because of increased heat and mass transfer but also allows processing of liquids, pastes and agglomerated solids in a dispersed state due to aerodynamic impact from the high intensity sound wave. Over last decades, applications of pulse combustion in drying have been exploited continuously and different pulse combustion dryers have been designed and fabricated. In pilot tests and technical reports on these dryers, short drying time, high energy efficiency and product quality are generally reported, which cause that pulse combustion drying is regarded as a technology of the future in convective drying.

This chapter attempt to introduce basic knowledge and state-of the art about this emerging technology and summarizes some recent studies in pulse combustion drying and equipment design. Following a concise description of pulse combustion and pulse combustor, the basic types of pulse-combustion dryers are presented, including spray dryers, fluidized bed dryers, impinging dryers, and dryers of special design. The existing commercial applications and pilot test projects are described and potential applications are identified.

Abstract

Increasing global demand for ‘fresh-like’ processed food products has forced food industries to investigate into various minimal processing techniques. Food processing in general has been associated with thermal processing, alone or in various combination with chemical and mechanical preservation and processing methods. However, thermal processing methods are energy intensive in nature and tend to reduce product quality and freshness at the cost of shelf-life gain. Advance technique such as microwave, radio-frequency and freeze drying do maintain the product quality but their implementation at industrial scale involves high operational and maintenance cost. An ideal processing method therefore would be one that can process food products without losing its quality, is energy efficient and is easily scalable. In this chapter, we discuss about ‘Electrohydrodynamic (EHD) Drying’, which is can be classified as a minimal processing technique. The heat and mass transfer principles involved in EHD drying have been extensively discussed and so has been the key consideration for designing an EHD drying system.

Abstract

This chapter presents the principle of fluidisation and its use in drying of food materials. Being a convective drying process, capacity and kinetics are limited by process conditions and material properties. The influences are discussed as well as presenting the main equations that describe drying in fluidised beds. The main focus lies on hot gas drying, additionally superheated steam drying as well as atmospheric fluidised bed freeze drying and microwave-assisted fluidised bed drying are presented and discussed.

Abstract

Airflow drying persists as the main dehydration operation. Indeed, the high expense of freeze-drying in term of equipment cost and energy consumption considerably restricts its use and confines its applications to high added value products (pharmaceutical products, cosmetics, etc.). However, airflow drying undergoes fundamental problems such as low operation performance, poor product quality and short reliability of the equipment. The time of drying is long; particularly at the end of the operation, which implies crucial energy consumption. The poor quality of the end product is related to thermal degradation and in particular to the compactness of texture as a result of the phenomena of shrinkage and case hardening. Another main problem common to all drying operations, including freeze-drying, is the safety of the end products. Swell-drying is defined as an operation that combines optimized hot air drying with instant controlled pressure controlled texturing. The improvement of texture, the preservation of sensory and nutritional quality, the possibility of manufacturing expanded granule powders and the reduction of drying time and energy consumption allow considering swell-drying as the most relevant drying process.

Abstract

Multiflash drying (MFD) process is based on the application of multiple cycles of heatingvacuum pulse to a solid food. Heat can be provided by convection (from hot air), conduction (by contact with a hot surface), microwaves, or by a combination of these methods. Due to the moderate temperatures applied to the drying food, and the sudden decompression step (vacuum pulse), MFD processes allow obtaining crispyanddried foods with very good nutritional and sensory properties. Vacuum pulses cause food texturization, which depends on the pressure drop rate during decompression. In fact, the dried products are similar to freezedried foods, but with more open structures, which result in higher crispness. The dehydration can be performed in relatively short processing times, when compared with traditional drying processes (e.g. solar drying, airdrying, vacuum drying and freezedrying). The short process time indicates clearly that this class of drying process presents a huge potential to the production of driedandcrisp foods at industrial scale.

Abstract

Drying is one of the most important industrial operations for preservation of food material. Due to the major limitations posed by convective drying methods, there is always a need for novel drying techniques which are technically, economically and environmentally sustainable. Based on the principle of moisture diffusion due to vapor pressure gradient, atmospheric freeze drying (AFD) offers a promising alternative to conventional drying systems. A cold gas with low water vapor pressure is used as drying medium to sublimate moisture directly from the frozen material at atmospheric pressure conditions. As a result the product gets dried at much lower temperature unlike convective drying. Thus, products dried with AFD retain better nutrition, texture and color and the process is also considerably cost effective. Major limitation of the AFD process is longer drying time, which can however be accelerated by using heat pump drying or new ultrasound technology. This chapter focuses on mechanism, benefits, limitations and comparative study of AFD with other drying methods such as hot air drying and vacuum freeze drying. It provides an insight regarding effect of AFD on properties of food material based on various studies reported in literature.

Abstract

Drying is a widely used method of food preservation. It leads to some structural changes in the dried material resulting in poor quality and rehydration. Freeze drying, though a costly process, reduces water activity without exposing the food material to high temperatures, eventually retains the original quality to a great deal. Moisture in the foods is frozen to ice which is sublimated under low pressure. Low pressure helps to vaporise the ice without transforming it to liquid, hence leaving the food structure porous in nature. The food is claimed to preserve the nutritional, sensory and re-constitutional qualities.

1.1 INTRODUCTION

Most food materials are composed of a very high percentage of water, which can be as high as 95%, and this makes them susceptible to microbial activity. Microbial activity spoils the products, leaving them useless for human consumption. It not only changes their taste and color but it may also develop toxins, thus making them unsafe. There are various methods for preserving food but in order to make them shelf stable, removing water from foods helps keep them from spoiling for a longer period of time.

Abstract

The damages caused by the tsunami surge of 26, December 2004 could not be recuperated. There is no second opinion for the above statement as attested by the consequences of tsunami surge on the coastal landforms, human lives, properties, biological assets, etc., The attempt made to evaluate the damages caused by the tsunami surge along the study area divulges various factors regarding the response of the coastal environment to this weird phenomenon. Kanyakumari district witnessed the tidal inundation of 50 – 450 m, the least along Colachel and the maximum in Kanyakumari and Muttom coasts. Run-up elevations were seen even up to 6 m in Manakudi and Colachel coasts. In major parts, the beaches of the study area had endured lofty erosion of beach sediments. High occurrence of Casualty was reported in the Coasts of Colachel, Kotilpadu, Manakudi and Azhikkal. Similarly, loss of man-made structures were also observed to be high along the Coast of Manakudi, Colachel, Kotilpadu, Azhikkal and Muttom. Costly articles like boats, fishing nets, etc., were also damaged in Kanyakumari, Pallam, Muttom, Kadiapatanam, Kesavanputhenthurai and Colachel. The quality of water has also been found to be affected with high level of pH and TDS in the coasts of Manakudi and Colachel. Such Colossal damages in the area is attributed to its geo-position exactly at the receiving point of the diverted tsunami surge by Sri Lanka. Bathymetry also seems to have played a crucial role in determining the intensity and angle of the seismic wave propagation in the area.

Keywords: Tsunami, India, Damages in Kanyakumari, Evaluation, Map, GIS.

Abstract

Geomatics (Remote Sensing and GIS) based tsunami damage assessment was carried out for Nagapattinam coast as a part of All India Coordinated Programme of NRDMS, Department of Science and Technology, New Delhi. The paper discusses the methodology and the inferences made for Nagapattinam region, Sirkali block and north Poigainallur panchayat village, holistically for the former and as case studies for the latter two. The regional studies show that the coastal geomorphology has played a significant role in tutoring the tsunami inundation and the damages with beach, dunes, tidal flats, backwaters and rivers / streams facilitating the inundation of tsunami. The studies in Sirkali block show the similar role of geomorphology, but the damage assessment carried out for Water bodies, soil and ground water show appreciable damage to Aquifer in the form of saltwater mixing / intrusion due to tsunami. Detailed geospatial data bases were generated village wise too. On the basis of the studies, possible remedial strategies were also suggested.

Keywords: Remote Sensing, GIS, Tsunami 2004, Damage Assessment, Tsunami mitigation, Nagapattinam.

Abstract

The tsunami has struck many coastal countries of South Asia on 26 December 2004 and caused greater devastation along Andaman - Nicobar and Indian coasts. In India, Tamil Nadu coast is worst affected in Kanyakumari, Nagapattinam and Cuddalore districts. Subsequently, damage assessment, in respect of natural and physical resources, was done using Remote Sensing and GIS in parts of Cuddalore and Pondicherry coasts. The structural damages were studied village wise and categorized as maximum, moderate and least affected areas. As far as the natural resources are concerned, the changes in geomorphology, land use/ land cover, soil and water have been studied. On the basis of the same, the risk maps were also generated in GIS environment.

Keywords: Tsunami, Damage Assessment, Remote Sensing, GIS, Cuddalore, Pondicherry

Abstract

The recent tsunami occurred on 26^thDecember 2004, caused great devastation along the east coast of Tamil Nadu, India. As the said tsunami has caused colossal damages, the impact assessment has become essential for tsunami mitigation measures. In this context, the extent of tsunami inundation, loss of lives, property loss and damages to physical and natural resources have been assessed in the tsunami affected area between Ennore and Mahabalipuram along the east coast of Tamil Nadu.

IRS LISS III PAN merged satellite data and IKONOS data were used for mapping the pre-tsunami geomorphology and land cover conditions and IRS-P6 PAN merged satellite data were used to map the post – tsunami terrain conditions including the inundations. From the study it is inferred that wherever buildings and population are denser the loss is more. Hence, vertical expansion may be needed as an alternative or to supplement horizontal expansion. Bio-shield along coastal areas, involving raising of mangrove forests, planting of casurina, salicornia, palms, bamboo and other tree species and halophytes which can grow near the sea will serve as speed-breakers for the up rising waves.

Keywords: Tsunami, Damage Assessment, Mitigation Measures, Chennai region.