eChapters

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

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.

A. In vitro Rumen Fermentation Technique for Forage Quality Evaluation

The term in vitro means “in a glass” in contrast to in vivo which is defined as “within the living body”. In vitro implies a close relationship to an in vivo measurement an in vitro reaction is used as a substitute for a reaction which normally occurs and is observed within a living body. the terms  “artificial rumen” and “in vitro rumen fermentation” are often used interchangeably.

The main advantage of the in vitro techniques rests in the ability to use them to study activity of micro-organisms away form the control and influence imposed by the host animal.

Mammals are homeothermic, meaning that they have the ability to control their body temperature within a narrow range in an environment whose temperature may change over a wide range.

India is experiencing a phenomenal spurt in the growth of livestock and poultry sectors through various timely and quality measures scientifically over a few decades. Milk production rose by a large leap from about 17.0 million tones in 1950 to about nearly 100 million tones in 2005 standing first in the world for maximum quantum of milk production. From about a ‘naught’ during 1950, the commercial layers have increased to 220 millions in 2005 producing 4500 crores of eggs every yearranking 5th in the world. The meat production is absolutely fascinating with 20 million birds in 1960 to about 2100 million in 2005 (Table 10.1).

Increase in ambient temperature, drought, rainfall, desert, feed and fodder scarcity, water scarcity and other climatic stresses are very common to tropical climatic conditions. The animals living in tropical climate have to undergo some modification for their survival under such extreme conditions. Interestingly, higher percentage of livestock is found in tropical and sub-tropical regions of the world. These areas are rich in animal resources. There are several descriptive and non-descriptive breeds of bovine distributed in different agro-climatic conditions of India. They possess several traits which make them adaptive to such climatic conditions. Identifying those traits and propagation of such traits is beneficial in near future in respect of climate change scenario. Climate change is the major concern for the improvement and sustainability of livestock under tropical climatic conditions. The rising of temperature and humidity is one of the major threats to animal’s productive performance that leads to great economic losses. Upadhyay et al. (2009) estimated 2% loss of milk production due to thermal stress in India. It has also been expected that 3.2 million tons reduction by 2020 and more than 15 million tons by 2050. The decline in milk production reported to be higher in crossbreds (0.63%) followed by buffaloes (0.5%) and indigenous cattle (0.4%) (Upadhyay et al., 2009). 

The climatic changes and global warming may impact the economic viability of livestock production systems in a significant manner. The possible consequences of increased ambient temperature on the livestock include reduced feed intake, reduced weight gains, lower milk production and lower conception rates during summer periods. Though animals can, to some extent, adapt to higher temperatures with prolonged exposure, the production losses are likely to be exhibited in response to higher temperature events. However, potential direct and indirect impacts of climate change on livestock production have not yet been thoroughly explored. Changes in availability and quality of fodder have also been identified as one of the major impacts of climate changes leading to lowered productivity of livestock species. Climate change could also affect the distribution of vector-borne livestock diseases. These changes occur as a result of shifts in the geographical ranges of ticks, mosquitoes, flies and other vectors.

The greenhouse effect is thought to be due to the absorption of solar infrared (IR) radiation by gases and the earth’s surfaces, which, as a result, is heated and then reemit IR radiation at low frequency with a high absorptive power. In fact greenhouse gases in the atmosphere are essential for maintaining life on earth, as without them the planet would be permanently frozen because all of the incoming heat from the sun would be radiated back into space by the earth’s surface (Moss, 1993). The threshold concentration of these gases at which their greenhouse effect would be minimized is not known, but it is accepted that their concentrations in the atmosphere should not be allowed to continue to rise. In recent years, there has been an increase in public concern over environmental damage originating from animal feeding operations.

Recent increase in extreme climate events threatens disruptive impacts on both animal and agriculture (Battisti and Naylor, 2009). Climate change is a global phenomenon, but its negative impacts are more severely felt by the poor people in developing countries. Moreover, rural poor communities rely greatly for their survival on animal and agriculture which belong to the most climate-sensitive economic sectors. Climate change is expected to intensify existing problems and create new combinations of risks. The incidences of droughts, snow-storms and blizzard like events have increased rapidly. The situation has further worsened due to factors such as widespread poverty, over dependence on rain-fed agriculture, inequitable land distribution, limited access to capital and technology, inadequate infrastructure, long term weather forecasts and inadequate research and extension. The impact of climate change is expected to heighten the vulnerability of animal systems and reinforce existing factors that are affecting animal production systems in many parts of the world.

Climate change has become a global threat as its impact is evident on the Earth. In the coming decades,the severity of climate change is expected to aggravate the ecosystem. Due to its vulnerable ecosystem and geographical location, the North eastern region (NER)of India that is home to about 40 million people is considered as one of the most climate sensitive areas in the country. The NER is among India’s least developed region andscarce information is available on the impact of climate change in this region. However, initial scientific research and field observations confirm that the region is suffering from the impacts of climate change already. The region comprising 0.26 million km2area occupying 8% of nation’s territoryconsists of the states of Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Sikkim. These states consist of a part of the east Himalayan region, which extends eastwards from Arunachal Pradesh to the Darjeeling hills of West Bengal. The entire region is a part of Indo-Burma and Himalayan hotspots i.e. characterized by rich biodiversity, heavy precipitation and high seismicity.

Global warming is the biggest long term threat to life on earth. Rise in temperature may drive thousands of species to extinction, trigger more frequent floods and droughts and sink low lying islands and coastal areas by rising sea levels. It is the result of rising atmospheric content of CO₂ mainly owing to burning of hydrocarbons or fossil fuels like as petrol and diesel. Destruction of forests and their degradation too contribute to rise in carbon dioxide levels. The IPCC (2006) projected the rate of warming for the 21st century to be between 0.8 and 4.4^ºC at various stabilized CO₂ levels in atmosphere and it is most likely to be 3°C by the end of this century. It could cost global economy almost $7 trillion by 2050, is equivalent to a 20% fall in growth if no action is taken on greenhouse gas emissions. If action is taken, it will cost only $350 billion due to climate change already taken place, just 1% of the global GDP. The winter 2007 was the warmest and recorded 0.85^ºC above average of 12oC and the previous highest was 0.71^ºC, which occurred in 2002 in Northern Hemisphere. The entire Europe Union recorded the warm winter, having more than 2^ºC above average. New York experienced the highest temperature of 21.7^ºC on a day in January, 2007 and the second highest was recorded as 17.2^ºC in 1950. The year 2007 was the warmest winter in the NHS. However, floods and excess rains were also noticed due to hurricanes and tropical storms worldwide in 2007. The year 2010 was the warmest year in India, followed by 2009. It was the second warmest year globally after 1998. It was also one of the wettest years globally in recent years and it was a landmark in annals of climatology.

Livestock farming is an integral part of crop farming and contributes substantially to household nutritional security and poverty alleviation through increased household income. Indian agriculture is an economic symbiosis of crop and livestock production with cattle as the foundation. Dairy animals produce milk by converting the crop residues and by products from crops which otherwise would be wasted. Dairy sector contributes by way of cash income, drought power and manure. Livestock provides for human needs by way of food, fibre, fuel, fertilizer, skin and traction. India has the largest livestock populations in the world. It has 57 per cent of the world’s buffalo population and 16 per cent of the cattle population. It ranks first in respect of cattle and buffalo population, third in sheep and second in goat population in the world. 70 per cent of the livestock are owned by 67 per cent of small and marginal farmers. 76 per cent of the milk is produced by weaker sections of society. Out of total livestock in the country, 37.28 per cent are cattle, 21.29 per cent are buffaloes, 12.71 per cent are sheep, 2640 per cent are goats and only 2.01 per cent are pigs. All other animals are less than 0.37 per cent of the total livestock. The species-wise breakup of livestock population in India (Table 16.1)

Livestock have the potential to be transformative; by enhancing food and nutrition security and providing the income to pay for education and for other needs, livestock can transform lives of many (Jimmy Smith et al., 2013). The projected growth of population is 9.6 billion in the year 2050 from the current population of 7.2billion (Gerber et al, FAO, 2013). The world demand for milk and meat in 2050 is expected to expand 58 and 73% respectively from their demand levels in 2010 (FAO, 2011). Nevertheless, the growth animal agriculture is not on par with the demand. Today, in a world of limited resources, in the face of climate change and a rising world population, a major issue is global food security (Augustine et al 2013). The key inferences of the latest approved summary for policymakers by the IPCC (2013) on climate change are 1). Warming of climate system is unequivocal and will continue beyond 2100. Global surface temperature change for the end of the 21st century is expected to exceed 1.5°C relative to 1850 to 1900 for almost all RCP scenarios 2). It is very likely that frequency of heat waves and heavy precipitation events have increased 3).

In India, being predominantly an agricultural country, livestock is emerging as a driving force in the growth of agricultural sector. Contribution of livestock to agriculture GDP has been rising steadily during the last three decades from 13.88% in 1980-81 to 27.28% in 2010-11 (BAHS 2012). About 70% population of the Country is engaged in agriculture and more than 50% of people below poverty line are associated with livestock production. India is blessed with a rich genetic resource of bovines, with an estimated number of 304.76 million (Livestock Census, 2007), which is 19% of the world. India continues to be the highest milk producing country in the world with an estimated production of 121.8 million tonnes during 2010-11 of which more than 53% is contributed by buffaloes (105.34 millions). Similarly, India ranks first in buffalo, second in cattle and goat, third in sheep, fourth in duck, fifth in chicken and sixth in camel population of the world. India is the third largest egg producer in the world (BAHS 2012). India posses a large treasure of domestic animal biodiversity with 37 breeds of cattle, 13 breeds of buffalo, 23 breeds of goat, 39 breeds of sheep, 6 breeds of horse/pony, 8 breeds of camel, 2 breeds of pig and 15 breeds of chicken registered under National Bureau of Animal Genetic Resources, Karnal.

The annual milk production in Tamil Nadu during 2009-10 from crossbred cows, non-descript cows and buffaloes were 42.28,7.89 and 7.61 lakh tones, respectively. Tamil Nadu had 59.83 lakhs crossbred female cows in the year 2007 as against 41.47 lakhs in 2003 with an annual growth rate of 9.59 per cent (Anon, 2010). With the increasing crossbred cattle population and average annual production, better management of the high producers becomes a necessity. Production and health of animals depend mostly on environment in which they live. A satisfactory environment for any farm livestock is the one that ensures not only optimal productivity but also meets the health and behavioral needs of the animals. A satisfactory environment is the one that satisfies the following four criteria: thermal comfort, physical comfort, disease control and behavioral satisfaction. The most important environmental interventions done in recent days are those that have been done in housing and other attempts to ameliorate the thermal environment. The effort of the body to maintain a stable internal environment to challenges from widely variable environments was first described by Claude Bernard (1878) and later referred to as homeostasis (Cannon, 1932). An environment in which stressors are minimized would likely be favorable for efficient production of products derived from domestic farm animals and for helping ensure the well-being of those species.

The demand for agricultural and livestock products is rising and the challenge to feed 8 billion people in 2020 is considerably enormous. Further, it is also hard to imagine meeting 2050-projected demand by raising twice as many poultry, 78% more small ruminants, 58% more cattle and 37% more pigs, without further damaging natural resources (Rivera and Lopez, 2012). Hence, sustainable development based on balance of ecology, economics, norms and values are to be considered at various levels of the scale: between food and farming systems, regions, nations and continents (Zipp, 2003). The food systems encompass activities related to the production, processing, distribution, preparation and consumption of food; and the outcomes of these activities contributing to food security (Fig. 14.1).The interactions between and within bio-geo-physical and human environments influence both the activities and the outcomes.

“Terra”per se is an extraordinarily complex, messy geophysical system with dozens of variables, most of which change in response to one another. The basic proposition behind the science of climate change is also rooted in the floral and faunal cohabiting with the Homo sapiens. Livestock and related fodder cultivation and the green waste generated in a farming enterprise are of extreme significance when we ponder over the climate change. Confusion and complacency reigns the thinking process and planning process related to climate change. Confusion in the sense, that risk communication in this regard is so placid. Complacency, we say due to the lackadaisical attitude of our policy makers. To make it very plain, fodder production sector as well as farm sector will suffer the most in Kerala for want of scientific thinking, planning and execution.

Heat stress induced by climate change is a serious issue of livestock industries worldwide (Bajagai, 2011). When environmental temperatures move out of the thermo-neutral zone (or comfort zone) animals begins to experience either heat stress or cold stress. Both these stresses require the animals to increase the amount of energy used to maintain the body temperature so that less energy is available for productive processes. Atmospheric temperature, relative humidity, air movement and solar radiation are the major factors that determine the heat load on animal. Thermoregulation is the ability of the animals to maintain their body temperature in cold or hot environments. It consists of behavioural, physiological and anatomical responses that affect energy metabolism. At lower temperature as a physiological adjustment to maintain the body temperature the animal increases the metabolic heat production by increasing the basal metabolic rate and uncoupling of oxidative phosphorylation. Hence the maintenance energy requirement of animals increases in a cold environment, which reduces the amount of energy available for production. From a practical point of view higher temperatures are much more dangerous for producing animals than a cold environment. Temperatures exceeding the higher critical level compromise animal performance not only by changing the energy and nutrient metabolism, but also by upsetting the body homeostasis, with detrimental consequences both for immune competence and for product quality. In general, livestock with high production potential are at greatest risk of heat stress, and require most attention.

The arid and semi-arid regions of India are drought prone and the availability vegetation of these regions is more acute during summer when the quality of the pastures becomes vulnerable. Small ruminants in the semi-arid regions need to adopt special physiological function to maintain thermal equilibrium. The reproductive efficiency of different breeds of sheep inhabiting in the semi-arid regions of India is relatively low (Arora and Garg, 1998).The nature of nutritional resources and management problems differs with climate, soil and vegetation, the physical process which governs the animals reproductive performance are the same; the female must reach puberty, show behavioral estrus and shed one or more ova which have then to be fertilized. Dietary nutrition promotes the programming and expression of the metabolic pathways that enable animals to achieve their genetic potential for reproduction. Nutrition has an important impact on the reproductive performance in sheep, but the magnitude of the effect on reproduction may vary with the season (White et al., 1983). Sheep are more prone to neglect compared to cattle and often suffer from lack of feed and fodder. The animals during the grazing are exposed to combined stress (Sejian et al., 2010 ab, and 2011) .This leads to decrease in body weight and loss of reproductive functions. Concurrently, Rhind and Mc Neilly (1986) showed that ewes with low body fat reserves had fewer large ovarian follicles and therefore the potential for subsequent maturation and ovulation declined. 

Increasing evidence over the past few decades indicate that significant changes in climate are taking place worldwide as a result of enhanced human activities. The inventions that were discovered during last few centuries, more so in the last century has altered the concentration of atmospheric constituents that lead to global warming. The major cause to climate change has been ascribed to the increased levels of greenhouse gases like carbon dioxide (CO₂), methane (CH₄), nitrous oxides (NO₂), chlorofluorocarbons (CFCs) beyond their natural levels due to the uncontrolled activities such as burning of fossil fuels, increased use of refrigerants, and enhanced agricultural related practices. The temperature increase is widespread over the globe and is greater at higher northern latitudes. Land regions have warmed faster than the oceans. January 2000 to December 2009 was the warmest decade on recordreported by NASA. These activities accelerated the processes of climate change and increased the average global temperatures by about 0.8°C (1.5°F) since 1880 (NASA,2010). Global average sea level has risen since 1961 at an average rate of 1.8 [1.3 to 2.3] mm/yr and since 1993 at 3.1 [2.4 to 3.8] mm/yr, with contributions from thermal expansion, melting glaciers and ice caps, and the polar ice sheets. Satellite data since 1978 show that annual average Arctic sea ice extent has shrunk by 2.7 % [2.1 to 3.3%] per decade, with larger decreases in summer of 7.4% [5.0 to 9.8%] per decade. Mountain glaciers and snow cover on average have declined in both hemispheres. It has also induced increased climatic variability and occurrence of extreme weather events in many parts of the world.

Yak (Poephagus grunniens)is the most remarkable and multipurpose domestic animal living at high altitudes of the Himalayas. Features common to the environment in which yak live are extreme cold, mountainous terrain, high altitudes with reduced oxygen in the air, high solar radiation and short growing seasons for herbageanda variable assortment of herbage, sparse insome areas. Generally, the yak habitat ranges from 3000-6000 m abovemean sea level (msl), where the alpine pastures are found and there is no absolutely frost-free period during any part of the year. Wilted herbage provides some sustenance for the yak at other times of year, but not insufficient quantity for their requirements (Fig. 9.1). Many of thecharacteristics of the yak can be regarded as adaptations to these conditions, in which cattle of other species have difficulty in surviving (Wiener et al., 2003).The yaks are considered as the life line of the highlanders in remote terrain because yak is the only sustainable livelihood due to non-availability of arable land for major agriculture. Yak husbandry is one of the important and indispensable aspects of the Indianstates, namely, Arunachal Pradesh, Himachal Pradesh, Jammu and Kashmir, Sikkim and Garhwal hills of Uttarakhand where other livestock species can hardly live but yaks can survive, reproduce and produce milk, meat, wool and other by-products.