Strategies for controlling microorganisms methods of preservation

In order to use the range of food-grade preservation methods available optimally, it is important to understand their characteristics, and any interactions that occur between them. Preservation is intended to prevent or retard deterioration that may otherwise be inevitable in co-product streams or end-products due to the effects of changes in their biochemical, chemical, physical or microbiological state. However, what follows deals with measures to control micro-organisms. The methods of...

Applied processing

Common treatments or processes that can be applied to kill microorganisms or retard their growth include chilling, freezing, heating, dehydration or a combination of these processes, such as occurs during extrusion. The effects of chilling and freezing on micro-organisms are to retard the biochemical processes that occur within the cell and that are necessary for metabolism or growth. The application of low temperature has been discussed earlier in this chapter. Equally, the application of...

Future trends

Anaerobic digestion of agricultural and food wastes to methane is a mature process that is being used within full-scale facilities worldwide (Table 23.8). Although methane is a relatively low-value product, methanogenic anaerobic digestion still represents the most economically viable technology. Hydrogen production via anaerobic fermentation has the greatest potential as a pre-process step that can be followed by a suitable secondary process step, such as bioconversion of VFAs to other...

Biosurfactants as fermentation products from yeast

Many microorganisms (including bacteria, fungi and yeasts) excrete different types of biosurfactants (including mycolic acids, glycolipids, lipopoly-saccharides, lipoproteins-lipopeptides and phospholipids) (Desai and Banat, 1997). Biosurfactants reduce the surface tension in the same manner as chemically synthesized tensides. The biological origin, low toxicity and their environmental bio-compatibility favour these fermentation products over others for application in many fields, including...

Combination approaches a case study glycerol production from oil waste

Glycerol production from oils provides a special case where both fermentation and enzymes are used in the processing of a food technology co-product. The process forms a closed circle, or cycle (Fig. 9.2), and biocatalysis is involved in almost every step of the procedure. Oils and fats are produced from renewable sources (e.g. oil plants, i.e. biomass) and are used in cooking, particularly frying. The waste (used) frying oils - usually selectively collected - (chemical name triglycerides) can...

Introduction

Fruit and vegetable processing (preservation or production of juice, wine, sugar, starch, oil, etc.) generates huge amounts of wastes in the European Community (EC) approximately 150 million tonnes are produced annually (Awarenet, 2004). Solid waste represents around 30 of the processed vegetables and can reach up to 85 for sugar production from sugar beet. Until recently in Europe, the principal end-use of these wastes was in the animal-feed sector. However, the rules that regulate the world...

Highpressure treatments

High-pressure treatments have been reported to cause inactivation of microorganisms and spoilage enzymes (Ludikhuyze et al., 2001). A pressure of 350 MPa has been cited by Knorr (1995) as the threshold in plant systems for an effect on structure and texture. Severe texture loss occurs through rupture of cellular membranes and consequent loss of turgor pressure. Pressure affects individual components such as starch, proteins and poly-saccharides. Fruit and vegetable enzymes such as...

Grape and wine

With 60 million tonnes per year, grape is the first fruit production in the world. Most of the grape is used for wine production. Some 60 of the world's wine is produced in the EC, especially in France, Italy and Spain. Wine production generates a large amount of solid waste (around 20-30 of the processed material estimated at between 5 and 9 million tonnes annually worldwide and 4.5 million tonnes in the EC) (Awarenet, 2004 Schieber et al., 2001) and wastewater (1 litre for 1 litre of wine...

Eliminating waste

The most straightforward and economical way to deal with waste would appear to be elimination. For example, any producers who can sell their product whole will not have a waste problem and, in some cases, can achieve the highest price for the product. Restaurants and markets in Asia often sell seafood live. But while this is relatively straightforward for crab and lobster, it becomes more difficult for suppliers of live fish. Fishing boats will need holding tanks, the fishermen must be taught...

Coproduct recovery and development

The spectrum of potential co-products (or by-products) is enormous, ranging from the very high end (fish oil capsules) to the very low (compost), and encompassing mince, gelatin, roe and other specialty organs, leather, liquid fertilizer, flavorants, and fish meal. Shellfish wastes lend themselves to some of the same products - namely flavorants, liquid fertilizer, meal, and compost - while shrimp, lobster, and crab shells contain chitin, which has unique benefits. The simplest and most...

Fractionation of whey

Whey fractionation imposes greater processing demands, but results in a wide range of products with unique functionalities and high value in the market place. Fractionated whey products include whey protein concentrate whey protein isolate a and p fractions bioactive proteins such as immunoglobulins, lactoferrin, lactoperoxidase and glycomacropeptide (GMP) and hydrolysed bioactive peptides. By-products from the ultrafiltration permeate include edible-grade lactose, pharmaceutical-grade lactose,...

Biotechnology

Enzymes, classed as microbial or non-microbial, are used to catalyse chemical reactions but they are specific proteases break down proteins, amylases break down starches and lipases break down lipids and fats. Exogenous enzymes are used to break down elements of plant tissues and cell-wall-degrading enzymes are present in fruits and vegetables. Pectic enzymes may be used to increase the efficiency of juice and colour extraction from grapes, citrus fruits and apples. Suspension of intact cells...

Biogas potential

Biochemical methane potential (BMP) and anaerobic toxicity assay (ATA) The methane potential of wastewater is related to COD and the treatment efficiency. The maximum theoretical yield of methane for carbohydrates is 0.35 L CHt g COD removed at standard temperature and pressure (Droste, 1997). The maximum methane potential of wastewater may not be realized in a treatment process for reasons such as the refractory nature of some of the organics. The BMP test is a procedure developed to determine...

Environmental factors influencing anaerobic biohydrogen production

The selection of the correct pH level is crucial to hydrogen production, due to the effects of pH on the hydrogenase activity or specific metabolic pathways (Dabrock et al., 1992). At pH values lower than 6.3 or higher than 7.8, the methanogenic rate may decrease or stop. Using a low pH environment to inhibit methane production in the acidogenic phase and to obtain dominant microbes for hydrogen production from sludge is considered feasible. Van Ginkel et al. (2001) reported the highest rate of...

Introduction consumer interests as a key driver to improve waste management in food processing

More than 10 million tonnes of food processing waste are produced within the European Community every year. The costs associated with handling the waste produced within the food industry constitute many tens of millions of euros, attributable to landfill costs and other waste disposal routes. However, this waste is also known to contain significant amounts of valuable components which remain unexploited as a result of current food-waste processing practices. There are many kinds of potentially...

References

Johnstona, n. and green, a. (2004), 'Food surplus reduction, recovery and recycling'. In Total Food Proceedings, edited by K Waldron, C Faulds and A Smith. Norwich, UK Institute of Food Research, pp. 35-39. may, d. and flannery, b. (1995), 'Cutting waste with employee involvement teams'. Business Horizons, 38 (5), 28-38. us-aep (US-Asia Environmental Partnership) (1997). 'Clean technologies in U.S. industries Focus on food processing'.

Membrane and membrane bioreactor process

Membranes are special devices, generally made up of synthetic polymers or inorganic material, that operate like barriers to divide a liquid from a solid stream. They are characterised by their different compositions and pore sizes. In food industry and wastewater treatment the size generally ranges between microfiltration (MF, 0.1-10 im) and ultrafiltration (UF, 0.001-0.1 im). However, reverse osmosis (RO, 0.0001-0.001 im) can also be of interest if salinity is excessive. All these systems are...

Conclusions

The wastes and residues of the fruit and vegetable industries constitute an interesting source of phytochemicals that can be readily extracted by simple methods and can then be used for the preparation of different products (functional foods, nutraceutical preparations or food ingredients). It is, however, essential to guarantee the product safety (pesticide levels and risk assessment of increasing phytochemical concentration). The preparation of these extracts is technologically feasible and...

Activated sludge process treatment

In an activated sludge treatment system, an acclimatised, mixed, biological growth of microorganisms (activated sludge) is brought into contact with organic material in the wastewater in the presence of excess dissolved oxygen and nutrients (nitrogen and phosphorus) (e.g. Metcalf & Eddy, 2002). The microorganisms convert the soluble organic compounds to carbon dioxide and cellular material, i.e. new biomass. Oxygen is obtained from applied air which also maintains adequate mixing. The...

Organic solid waste

The major options for the stabilization and re-use or disposal of organic solid waste from meat processing and rendering operations are composting (aerobic digestion) and vermicomposting, anaerobic digestion, disposal to landfill and incineration (Salminen and Rintala, 2002). Incineration has recently been adopted by the meat industry as a viable option as it is considered among the most effective methods for destroying potentially infectious agents (Ritter and Chinside, 1995). Composting is an...

Renewables in the food industry

There are a number of slightly different definitions of renewable energy. The US Energy Information Administration (EIA, 2005) defines renewable energy as 'Energy obtained from sources that are essentially inexhaustible (unlike, for example, fossil fuels, of which there is a finite supply). Renewable sources of energy include wood, waste, geothermal, wind, photovoltaic, and solar thermal energy'. The definition presented by the Texas Renewable Energy Industries Association (TREIA, 2005) carries...

Altered gaseous environments

Air is composed of 78 nitrogen, 21 oxygen, 0.9 argon, 0.03 carbon dioxide and assorted other gases. Oxygen is consumed and carbon dioxide is produced during respiration in air. The diffusion of gases into and out of plant tissue is controlled by the difference in their concentration across a barrier, the thickness of the barrier and the permeability of the barrier this relationship is summarized in Fick's law of diffusion. As fruit become larger, the surface area through which gases diffuse...

Risk management and transparency

Consumer risk perceptions differ from those held by other stakeholders involved in food production and risk analysis. It has been well established that people's risk perceptions determine how they react to different hazards. Some factors (for example, whether a hazard is voluntary in terms of exposure or technological in origin) predict people's responses across different hazard domains (i.e. the extent to which risk is perceived to be involuntary increases the threat perception for all kinds...

Implications for food processors

Food processing is a costly enterprise. Research and development costs are very high, but profit margins are low compared with other sectors. The level of regulatory scrutiny currently imposed on new food products is high and unprecedented, increasing the cost of developing novel products. The development and costs of such regulatory requirements may have significant negative impacts on by-product management in food processing. This implies that only a few companies may decide on the management...

Related titles

Environmentally-friendly food processing (ISBN-13 978-1-85573-677-1 ISBN-10 1-85573-677-2) With both regulation and consumer pressure increasing, the food industry needs to ensure that its production methods are sustainable and sensitive to environmental needs. This important collection reviews ways of analysing the impact of food processing operations on the environment, particularly life cycle assessment (LCA), and techniques for minimising that impact. The first part of the book looks at the...

Phytochemicals present in plant food residues

Procyanidins Resveratrol

The main groups of plant secondary metabolites that are suitable for use in nutraceuticals or as functional food ingredients are the terpenoids, the polyphenols and the organosulphur compounds. The terpenoids (Fig. 17.1) are biosynthesised by the acetate-mevalonate pathway and constitute a group of lipophilic compounds with a wide range of molecular weights, biological properties and potential uses (Bartley and Scolnik, 1995). The monoterpenes (10 carbon atoms) are generally volatile compounds...

Lessons from other industries

The retting process (Meijer et al., 1995) demonstrates the role of fermentation in the food industry, albeit that the fermentation is uncontrolled compared with many food industry applications. For bast fibres such as hemp and flax, dew retting is the main process currently used for separating the fibres from other plant tissues. The plant stems are left in the field to 'weather' until the fibre-matrix bond is broken down a fibre mass is obtained, which is then broken up in a decorticator, a...

Residues generation and key reasons for coproduct recovery

The waste portion in the processing of some fruits and vegetables can be as large as 70 of the harvested material, as is the case of artichokes, passion fruits and some lettuce cultivars. In leaf vegetables (lettuce, spinach, Swiss chard, etc.) the external leaves are often removed as they are too hard and green and often have some defects (bruises, cuts, etc.). In other products, the edible portion is the flower (or the flower heart, as in the case of artichokes) and in this case the leaves,...

Value of biohydrogen as a fuel resource

Despite its clean and green nature, most hydrogen is currently produced primarily from non-renewable sources, such as natural gas, oil and coal. Fig. 23.4 shows the ratio of sources used in worldwide production of hydrogen (US DOE Website, 2004a). Hydrogen production is 500 billion nm3 year and electrolysis, the only non-fossil fuel source, comprises only 4 of total hydrogen production at 20 billion nm3 year. Unfortunately, hydrogen production via electrolysis and thermal decomposition of water...

Use of the whole byproducts 1631 Dietary fibre

The concept of dietary fibre is well established (even though the definition of dietary fibre may still be the subject of debate) and the nutritional benefits (protection against certain types of cancer, regulation of food transit through the digestive system, blood cholesterol lowering) of dietary fibre intake are generally accepted (Lee and Prosky, 1995). Whatever the definition, plant cell walls are the main sources of dietary fibre as they are composed of polysaccharides (mainly cellulose,...

Societal issues related to sustainability 221 Sustainability

The key underlying driver for upgrading food-chain waste is improved sustainability, linked to the consumer attitude of concern for the environment. Co-product exploitation and waste minimisation are vital to sustainable development. Literally, sustainability means 'the ability to sustain'. This implies maintaining something in the same state, or keeping it in the same state for a period of time, or providing support by giving help and encouragement or mobilising resources. In recent decades,...

Treatment present stateoftheart and future trends

The task of minimisation of water usage and minimising wastewater discharge has received considerable attention over the last few years as water has become more and more costly and an environmentally strategic concern. Most of these trends are general and are not limited to food processing. Smith (2005) summed up the main water usage and water and waste-water minimisation measures as follows. 1 Process changes. These include increasing the number of stages in an extraction processes that use...

Good housekeeping recommendations for specific industries to reduce waste

The principal processing steps include (i) general cleaning and dirt removal (ii) removal of leaves, skin, and seeds (iii) blanching (iv) washing and cooling (v) packaging and (vi) clean-up (US-AEP 1997). Waste includes peelings, stems, seeds, shells, etc. and products that are off-spec, damaged, out-of-date, or returned. Reduce waste by using air flotation units to remove debris from raw fruits and vegetables. In addition, try to wash, grade, and trim crops in the field so that the waste can...

Important sources of highvalue coproducts 1751 Fruit processing

Fruits are processed to produce fresh-cut products, an industry increasing steadily in importance, and this generates large amounts of residues (peels, stones, husks, etc.). Fruits are also used for the production of juices, wines and oils by pressing technologies, leading to press-cake residues generally very rich in bioactive secondary metabolites. Residues are mainly generated in the juice and cider production industries. The wastes are in the form of pomaces, and include peels and seeds in...

Biological removal of phenols

OMWW phenolic compounds, and in particular the lower molecular weight ones, are toxic molecules. Fiorentino et al. (2003) characterized phenolic products such as 1,2-dihydroxybenzene (catechol), derivatives of benzoic acid, phenylacetic acid, phenylethanol and cinnamic acid. The OMWW were fractioned by ultra-filtration and reverse osmosis techniques and tested for toxicity on aquatic organisms from different trophic levels the alga Pseudokirchneriella subcapitata the rotifer Brachionus...

Chemical oxidation

Many advanced chemical oxidation technologies are based on the production of hydroxyl radicals, possessing an extremely high oxidation potential (+2.73 V) to reduce the temperatures (and hence the pressures) required for wet oxidation, it has long been proposed that organically polluted wastewaters should be treated with Fenton reactant, i.e. hydrogen peroxide in the presence of iron salt. In the Fenton process, the completion of oxidation is dependent on the hydrogen peroxide organic pollutant...

Enzymefiltration combination processes

Whey is a by-product in cheese production, where mainly protein and fats are precipitated in the milk by addition of a 'coagulating' enzyme (chy-mosin or rennin, a carboxyl acid peptidase). The remaining liquid phase (whey) contains 5 sugars, mainly lactose. Previously, whey was used as a feedstock but a more economic use involves hydrolysing the lactose to produce glucose and galactose. A high substrate content is favourable in order to reduce downstream processing costs. In milk, the lactose...

Preface

The global intensification of agriculture and food production has led to the creation of vast quantities of food co-products and wastes, often in centralised locations as food processors seek to achieve economies of scale. Typically, the food industry produces considerable amounts of biodegradable wastes, including large volumes of effluent and residues with a high biological oxygen demand (BOD) and chemical oxygen demand (COD) content. Their uncontrolled spoilage and decomposition lead to the...

TPAD system

The TPAD system was adapted to the two-stage nature of anaerobic metabolism, and the concept has been evaluated in detail by various researchers. The system is also referred to as 'phase separation' (Fox and Pohland, 1994). Pohland and Ghosh (1971) first proposed the physical separation of acid formers and methane formers in two separate reactors where optimum environmental conditions for each group of bacterial communities would be provided to enhance the overall process performance. In order...

Drying

Drying is a separation process and can be carried out using a number of techniques. Removal of water can be by mechanical expression, by evaporation at atmospheric or reduced pressures, and by freezing the water and subliming the ice. Sorption isotherms provide the base relationship between moisture content and equilibrium relative humidity that underlies much of drying technology. In fact critical processing points may be marked on the isotherm to denote packaging, storage and atmospheric...

Methanogenesis

The formation of methane, which is the ultimate product of anaerobic treatment, occurs by two major routes. Formic acid, acetic acid, methanol and hydrogen can be used as energy sources by the various methanogens. The primary route is the fermentation of the major product of the acid-forming phase, acetic acid, to methane and carbon dioxide. Bacteria that utilize acetic acid are acetoclastic bacteria (acetate splitting bacteria). The overall reaction is The acetoclastic group comprises two main...

New products

The first new products obtainable from oil wastes are isoflavones, which are extracted from the waste of soy protein production. Isoflavones are structurally close to oestrogens and have been proved to aid in the fight against breast and prostate cancer. Another product is tocotrienol, which is a strong antioxidant, like vitamin E, that is extracted from palm oil processing by-products. From the palm oil waste stream there is also the possibility of extracting a natural P-carotene. Additional...

Sources of further information and advice

Waste minimisation technical assistance may be obtained from governmental agencies, consulting engineers, professional organisations, non-profit-making organisations, and the internet. The following information details some of the services available in the UK. In March 2005, a new 284 million initiative was launched to help businesses reduce waste and manage resources more efficiently. The Business Resource Efficiency and Waste (BREW) programme specifically targets waste minimisation. Free...

Wastewater

The consumption and discharge of water by food industries, in particular the meat processing industry, could be considerably minimized by means of water re-use (Casani et al., 2005). However, water re-use has not been widely practised due to a number of constraints and barriers. These constraints range from economic and legislative barriers, to the perceived complexity of testing and documentation required, and the negative perception and poor acceptance of water re-use by the consumer....

Simple design

To become competitive, an efficient high-rate reactor system should be simple. For example, introducing waste into the bottom of a UASB reactor or IBR at pressure greater than the head pressure is all that is needed to operate the reactor, providing there is an effective method to separate solids, liquids and gas at the top. The ASBR does not require an upflow pattern and a gas-solids separation system is unnecessary, however it does require equipment and controls for filling, mixing, settling...

Starch production

Starch is extracted from corn (60 ), wheat (20 ) and potato (20 ). Starch production generates around 8 million tonnes of waste every year in the EC. This section will focus on potato starch extraction as this process produces the majority of the waste (5.5 million tonnes per year). Some 200 kg of starch is extracted from 1 tonne of potato wastes represent 80 of the raw material. They are essentially produced during rasping of the potatoes and extraction of starch, resulting in a mixture of...

Properties of hydrogen as a fuel resource

Hydrogen gas is the only alternative clean fuel source that produces no greenhouse gases, with water as the only combustion by-product. Combustion of hydrogen in automobiles is 50 more efficient than gasoline, since hydrogen can be combusted very lean, and gasoline must rely on stoichio-metric mixtures and catalytic control of the exhaust gases for emission control (Swain et al., 1983 Mizuno et al., 2000). It may be possible to store compactly as a metallic hydride (Billings, 1991). It is the...

Conclusions and future trends

The processing of red and white meat results in the generation of large volumes of waste material. This review has examined the various approaches that a modern meat processor should consider in 'managing' this waste material, including its minimization, responsible diposal and value-addition. All can play a part, either in isolation or in combination, in improving processing efficiency and effectiveness, addressing legislative requirements and enhancing the financial, social and environmental...

New product design

New product design can result in benefits throughout the life cycle of the product, with reduced waste, reduced energy and water consumption and higher yields. The new process often requires new process equipment and marketing efforts to establish the new product in the market place successfully. An example is the ultrafiltration of milk for cheese manufacture which increases the recovery of whey proteins in the cheese and reduces whey volumes. Cheese produced from these processes is smoother...

Introduction importance of microbiological risk management in the stabilisation of coproducts

Microbiological stabilisation is an imperative that should be designed into co-product processing systems. This is essential in order to avoid the growth of micro-organisms, which could have two major implications. Firstly, the micro-organisms may utilise or convert some of the co-products and hence diminish yields or corrupt the process (essentially, act as spoilage organisms). Secondly, the organisms may be capable of causing illness to workers involved in the process, or cause illness in...

Modeling of solubility and mass transfer

Mathematical expression of the kinetics of supercritical extraction phenomena can be of great significance for further studies, as well as in understanding general behavior of extraction phenomena for given components. Knowledge of phase equilibrium behavior and generation of phase equilibrium data - such as solubility, distribution coefficients and selectivity of separation of extractables - in supercritical fluids is of great importance for improved understanding of the process. All...

Land disposal of wastewaters

The application of wastewater to land is a low-capital and low-operating cost method for the treatment of food processing wastes, provided sufficient land with suitable characteristics is available. This method has been the most highly used 'technology' for wastewater treatment for a long time. Obviously, it cannot be very effective and recent legislation tends to limit the possibility of spreading food wastewaters on land. However, this system still has its importance in wastewater treatment....

Response to adverse environments 731 Temperature

Cold temperatures are the foundation of most storage technologies. Chemical reactions proceed at a slower rate at lower temperatures. Changes in reaction rates with temperature are often characterized by their respiratory quotient (Q10). The rate of simple chemical reactions is halved by a 10 C reduction in temperature and is therefore said to have a Q10 of 2. The rate of many enzymatic reactions shows a more pronounced decline with temperature and these have a Q10 greater than 2. For example,...

Legislation

A Community Strategy for Waste Management was published in 1989 to address the problem of increasing amounts of waste being disposed. The Waste Strategy, as amended in 1996 (COM(96)0339), lays down legal principles that will form the framework of the European Waste Policy. These legal principles include The prevention principle waste generation should be minimised as much as possible. The polluter pays principle whoever produced the waste should pay for handling it. The precautionary principle...

Comparison of TSAD and TPAD systems

Although few studies have been reported that compare the TSAD system to the TPAD system, subtle differences in system configuration such as Table 23.4 Major advantages and disadvantages of the TPAD system Advantages Isolate and optimize the conditions for potential rate-limiting steps Hydrolysis encouraged during first phase Methanogenesis encouraged during second phase Improve reaction kinetics and stability improved reactor stability to organic and hydraulic overloads select for...

European legislation

Water use and wastewater discharge are covered by both national and international legislations. For European Union (EU) member countries the legislation follows ECC directives, the most relevant are listed below see the Europa website for further details (Europa, 2005). The new European Water Policy river basin management. The Water Framework Directive (2000 60 EC). Towards a European action programme on flood risk management. Strategies against chemical pollution of surface water under the...

[82

The potential for destructuring of food processing waste 173 Molecular basis of mechanical behaviour Polymers are classically described as amorphous (e.g. polystyrene) or semi-crystalline (e.g. polyethylene) structures, the properties of which change dramatically with increasing temperature at the glass transition and crystalline melting temperatures, respectively. The glass transition marks the change in molecular mobility and is often identified by differential scanning calorimetry and...

High retention of biomass and biomasssubstrate contact

A high concentration of biomass is required for a high loading potential for anaerobic processes. The process loading, based on the food to microorganism (F M) ratio, should be low in order to achieve efficient biomass formation and solids separation. A low F M ratio at high loading rates can be achieved when the biomass concentration is high. The sludge in high-rate anaerobic systems often forms granules that help in retaining biomass and may also serve as an internal clarifier. High-rate...

Thermodynamic modeling

An equation of state (EOS) is widely used to represent the relationship of temperature, pressure and composition of compounds in supercritical fluids. Solubility may be predicted as a function of the temperature and pressure along with solute and solvent properties. Some of the most commonly used EOS models are the Peng-Robinson and Soave-Redlich-Kwong equations. Both produce similar results however, the Peng-Robinson equation of state (PR-EOS) will be discussed here as it is more widely used....

X0ps[1011

Where C0 is the total solute concentration in the particle (kg m3), the particle porosity is represented by eP, K is the partition coefficient of the solute in the solvent, x0 is the initial solute mass ratio in the particle (kg solute kg particle), and the real solid density pS is measured as kg particle m3 particle volume. The solute mass balance equations within the interstitial space and the porous particle can be written in terms of dimensionless variables. The use of dimensionless...

Wounding

Wounding plant tissues elicits the production of a wound signal which propagates into adjacent tissue and initiates a number of genetically programmed responses. Over their evolutionary history, plants have acquired a limited number of responses to adverse conditions. Each type of stress does not therefore evoke a unique response, but different types of stresses (e.g. mechanical damage from cutting, insect feeding, or flexing in the wind exposure to toxic levels of certain chemicals exposure to...

Milling methods

Corn refining is a two-step process that involves the wet milling and processing of corn. Shelled yellow dent corn, which has been removed from the cob during harvesting, is cleaned and steeped (softened) in tanks with a water-based solution, releasing starch. Steepwater is drawn off and the corn is milled, breaking the germ loose. Mechanical and solvent processes during germ separation extract oil from the germ. The corn leaves the germ separator in a water suspension for further grinding to...

Mass transfer modeling

The SFE process from natural materials generally involves the releasing of solutes from a porous biological matrix into the supercritical solvent via internal and external mass transfer mechanisms. The first part of the extraction, the CER period, is governed by the solubility equilibrium between the CO2 solvent and extract. Once the easily accessible surface extracts are depleted, molecular DC mass transfer occurs and an FER period is seen. Eventually, diffusion of the extracts through the...

Chapter

El-Mashad Department of Biological and Agricultural Engineering University of California One Shields Avenue Davis CA 95616 USA email rhzhang ucdavis.edu Chapter 13 Alan Ferguson Alamanda Pty Ltd 77 Temple Street Coorparoo Brisbane Queensland 4151 Australia Dr Rosalie J. Durham* and J. A. Hourigan Professor Joe M. Regenstein Dept. of Food Science Stocking Hall Cornell University Ithaca, NY 14853-7201 USA Maud Panouill , Marie-Christine Ralet, Estelle Bonnin* and...

Improving end waste management in vegetable oil production

Several methods have been proposed for OMWW and olive disposal, based on evaporation ponds, thermal concentration, physicochemical and biological treatments, as well as their application to agricultural soils as an organic fertilizer either directly or after a composting process. Various processes have been developed for the treatment of organic fractions of differently composed wastes to upgrade them to more valuable, re-usable products, organic acids and solvents, and biopolymer or...

Key reasons for exploiting plantderived compounds from coproducts

The key reasons that support the incorporation of specific plant-derived compounds in pharmaceutical and cosmetic products are summarised below. 18.2.1 Recovery of by-products from the food and food-processing industries environmental benefits The food and food-processing industry produces considerable amounts of wastes, residues, effluents and by-products which contain important amounts of potentially interesting compounds (Laufenberg et al, 2003). The disposal of these residues often creates...

Combining biological and chemical oxidation procedures

Studies have combined chemical oxidation and biological systems to treat biorecalcitrant pollutants, with potential advantages for wastewater treatment. The combination of chemical and biological oxidation is becoming a successful alternative to conventional treatment technologies. In this way, the quantitative degradation of the recalcitrant organics into CO2 and H2O by strong extensive chemical treatment is no longer necessary. The new goal is a moderate transformation by chemical means of...

Separation processes

Oilseeds contain oil, protein and starch in plant cells. Destructuring processes include cracking with corrugated rolls, dehulling, decorticating and flaking (Galloway, 1976). Seeds vary in oil content and the equipment required differs. Soybeans are solvent extracted whereas cotton seed, rape-seed, peanut, sunflower, palm and copra are examples where pressing followed by solvent extraction are undertaken (see Fig. 8.7). The main requirement is to avoid excessive damage, although cell and...

The three tiers of microbiological safety

This is very much a hands-on concept and involves general hygiene in production, preparation and processing of the co-product streams and of the end-products derived from them. It involves ensuring that the product remains 'microbiologically clean' throughout and that no additional microbiological contamination occurs during the processing. However, it does not quantify the initial numbers of contaminating micro-organisms, does not determine the risk presented by them, and nor does it introduce...

Effect of destructuring on foods and their components 821 Tissues

There is a hierarchy of structures in plants and in meat (Fig. 8.1). Meat includes a number of different tissues (Lillford, 2001). Edible muscle tissues are of interest for food use and consequently for co-product recovery. Muscle cells and fibres approximate to long, small-diameter cylinders. Fibres are surrounded by the sarcolemma comprising cell membrane overlayed with endomysial connective tissue (Aguilera and Stanley, 1990). Cereals, vegetables and fruit are the principal plant foods in...

Key reasons economic environmental legislative etc to optimise processes to minimise water use and wastage

Water is used in most process industries for a wide range of applications. Industrial processes and systems using water are today being subjected to increasingly stringent environmental regulations relating to the discharge of effluents and there is a growing demand for fresh water. The changes taking place and the pace of these changes have increased the need for improved water management and wastewater minimisation. The adoption of water minimisation techniques can effectively reduce overall...

Cooling

Normally chilling is the key to the cool chain transport and storage to reduce metabolism and extend shelf life. However, damage as a result of chilling injury can occur in some crops - usually those of tropical or sub-tropical origin - although some temperate crops, such as asparagus and potato, are susceptible at low but non-freezing temperatures (Saltveit, 2003). Extensive microstructural changes may occur when ice crystallises. The rate of freezing becomes an important variable and affects...

Food wastewater production and characteristics

A typical characteristic of the food industry is the great variability in the length of the processing season and the amount of material processed. Also associated with this industry is the wide variation in both the amount of water used for processing and the waste loading from process plant to process plant. In general, wastes from the food industry contain biodegradable organic matter in the form of both dissolved and suspended solids, fats, oils and greases. Therefore, typical pollutant...

Stabilisation pond treatment

A common practice for improving the effluent treated in the aerated lagoon is the use of a stabilization polishing pond system (Costa-Pierce, 1998). This system depends on the action of aerobic bacteria on the soluble organics contained in the waste streams. The organic carbon is converted to carbon dioxide and bacterial cells. Algal growth is stimulated by incident sunlight which penetrates to a depth of 1-1.5 m. Photosynthesis results in the production of excess oxygen which is available to...

Sterols

Another important product obtainable from vegetable oil wastes is sterol. Although steroid drugs represent only a small part of the world market of pharmaceuticals, there is a great demand for new and cheaper steroid raw materials for their production (Dias et al., 2002). The choice of starting material has always had a critical impact on the steroid-manufacturing industries. The most common and economical process for the production of steroid pharmaceuticals is the partial synthesis from...

Operational variables

The HRT is a measure of the rate of liquid flow in to and out of a reactor. Under steady state conditions, the HRT is defined as follows HRT total volume of liquid in the system volume of liquid changed per day In a completely mixed system that employs continuous mixing, all the contents of the system have the same residence or retention time. In such a system, the detention time is governed by the replication time of the slowest growing organism of the microbial community. Below this value,...

T

Fig. 8.7 Flow diagram for soybean oil extraction (from Aguilera and Stanley, viscosity and soften for flaking. Distillation is required to separate the solvent and extracted oil since solvent extraction also results in a carry over of impurities leading to a need for further oil refining. Solvents for extraction include hydrocarbons, alcohols, ketones and water. The plant cellular structure is disrupted progressively by crushing and flaking. Pressing is an alternative process that can be...

Trickling filters

Trickling filters, utilising plastic media in columns 4.5-6.0 m high, have been used in the treatment of high-strength fruit and vegetable wastewaters (3000-4000 mg l BOD5). High liquid recirculation rates and forced air circulation are used to achieve BOD5 removals up to 90 . However, these processes tend to fail with the high organic load rates that are typical of some food processing wastewaters as, for example, in the cheese industry (Rusten et al, 1996). Wastewater is distributed by...

Chemicals and biofuels production

Biotechnology, in particular the fermentation sector, has become more and more attractive in recent years for the production of chemicals and biofuels from organic wastes (Willke and Vorlop, 2004). In fact, there are numerous possibilities for replacing chemical techniques with biotechnological methods based on renewable resources. The most important biogenic sources of raw materials for industrial chemicals are oil plants (oil, fat, glycerol, celluloses) starch plants (starch, inulin,...

Cells

The primary elements to consider in destructuring cells are the protein collagen in animal tissue and the carbohydrate cellulose in plant tissue. Parenchyma cells contain solutes in water that are surrounded by a semipermeable membrane (Waldron et al., 1997). This is important in the context of many processes because water can pass through the membrane but larger molecules like sugars cannot. The outflow of water from the cells makes the tissue flaccid or wilted with a less desirable texture...

Process optimisation

Process optimisation reduces resource consumption by optimising existing processes. Examples of improvements that are easily achievable in the dairy industry, as identified by Prasad et al. (2004), include Optimising start-up shut-down procedures and changeovers by fine tuning timers and accurately detecting product interfaces to reduce product waste e.g. National Foods, Australia are now saving 60 000 L milk year by such optimisation. Optimisation of production scheduling so that process...

Key reasons to minimise waste

The amount of food waste and by-products generated in the European Union (EU) is approximately 222 million tonnes annually. The food industry produces an immense amount of biodegradable waste that causes problems in landfills and wastewater treatment systems. When buried in landfills, biodegradable waste generates methane (which contributes to the greenhouse effect) and causes the release of toxic materials that can contaminate groundwater. Wastewater treatment systems can be overloaded with...

Dairy product production

Milk can be converted into a wide range of dairy products - including fresh products such as modified milk, yoghurt, desserts and custards, or longer-shelf-life products such as cheese or butter, long-life milk, milk powders and whey powders. Overall about one-third of world milk is consumed as fresh market milk one-quarter is used in cheese making one-fifth is processed into butter, milk powder and casein. The remainder is processed into soft or frozen products, condensed and evaporated milk,...

Highrate anaerobic bioconversion system

Higher treatment rates reduce capital costs and make it easier to build large systems because the vessels needed to contain the waste are smaller. Successful anaerobic treatment requires a microbial balance between the fast-growing acidogens and the slow-growing methanogens. Because of the slow growth rate of methanogens, efficient biomass retention is required for successful high-rate anaerobic system performance (Stronach et al., 1986 Wohlt et al., 1990). To achieve rapid anaerobic treatment...

Technological processes for phytochemicals extraction from residues

Knowledge of phytochemical solubility, chemical and biochemical stability, and tissue localisation are essential in order to develop the extraction techniques and the technological processes for the preparation of high-value extracts. As a general rule phytochemicals are poorly soluble in water, and are better extracted with organic solvents. For the more polar compounds mixtures of alcohols and water are the solvents of choice (Harborne, 1973). For the most lipophilic phytochemicals, the use...

Jet loop reactors

The jet loop is an activated sludge system with a tall and deep oxidation vessel that achieves high dissolved oxygen concentrations due to a high liquid-air contact time. This allows for a high oxygen availability and the possibility of dealing with very concentrated wastewaters. Table 21.9 reports some interesting data that can be found in literature for this process. As shown from reported data the removal efficiency for wastewaters with high organic content is generally higher than 93 .

Lipids from natural products

Prospective applications for the SFE of lipids or oils, apart from common vegetable oils (soy oils, corn oil, rice bran oil, sunflower oil, olive oil, etc.), also include animal fats, fish oil, oil from seaweeds and oil from microorganisms like fungi (Walker et al., 1999 Mukhopadhyay, 2000 Shen et al., 1996). Major components of lipids include monoglycerides, diglycerides, triglycerides and free fatty acids (FFAs) minor constituents include sterols, toco-pherols, gums, alkaloids, flavonoids,...

Food Processing References

Ansoff, h. i. (1957), Strategies for diversification. Harvard Business Review, September-October, 113-124. awarenet (2004), Handbook for the prevention and minimization of waste and valorization of by-products in European agro-food industries. Deposito Legal BI-223-04. DEFRA 1 DEFRA 2 Europa (2006), Website for EU legislation http europa.eu.int eur-lex en search search_lif.html. European Topic Centre on Resource and Waste Management (2006), Definitions of waste maslow, a. h. (1970), Motivation...

Origin and general characterisation of the byproducts 1621 Fruit and vegetable juices

Juice production concerns a large variety of fruits and vegetables and generates annually around 5.5 million tonnes of solid waste and between 0.5 and 6 m3 of wastewater per tonne of raw material. The amount of solid waste depends strongly on the vegetable or fruit (from 5 for tomato to 75 for passion fruit) (Schieber et al., 2001) but represents an average of 30-50 of the raw material. Using enzymatic liquefaction can reduce the quantity of waste however the degradation of cell wall material...

Sugar production

Sugar is mainly produced from beet (in Europe) or cane (in warmer climates). In the EC, sugar beet production generates more than 100 million tonnes per year of solid waste and around 0.5 m3 of wastewater per tonne of raw material these wastes are generally spread on land. For every tonne of sugar beet, 140 kg of sugar is extracted, resulting in 86 waste. Beets are first flumed by water and separated from leaves, weeds, beet tails and soil. This represents around 100 kg of waste for a tonne of...

Literature and conferences papers books relevant conferences and journals websites to study with a short evaluation

There are a number of case studies available, for example Dilek et al. (2003), a sugar plant Hyde et al. (2001), food and drink industry - a demonstration project in East Anglia, UK Vigneswaran et al. (1999), a prawn farm. Wrigley (2004) presented an interesting example of on-farm dairy processing which provides various recommendations for good practices including some interesting cheese production figures. The need for integration of water and wastewater management with farm planning was an...

Further reading

APEC Center for Technology Exchange and Training for Small and Medium Enterprises, 'Developing practical solutions'. http www.actetsme.org archive eco-efficiency food p12.html. Beveragedaily.com (23 August 2005) 'UK to increase targets for recycling packaging waste'. 62046& k uk-to-increase. carter, j. and narasimhan, r. (1998), 'Environmental supply chain management, Center for Advanced Purchasing Studies, 1998 - focus study, executive summary'. Centre for Excellence in Cleaner Production,...

Water contamination and wastewater treatment

The food processing industry generates large volumes of waste water and large amounts of solid waste that can produce environmental problems and whose management increases the cost of processes. It is normally necessary to adopt some measures to decrease the environmental impacts of the processes and reduce the costs that are incurred in the treatment and the disposal of the wastes generated. These measures should be focused on the reduction of the generation of wastes rather than their...

Anaerobic sequencing batch reactor ASBR

The ASBR process is able to handle soluble influent streams and also those with higher TSS (Dague et al., 1992 Schmit and Dague, 1993). The ASBR is a non-steady state or pseudo-steady state, anaerobic treatment system. By definition of non-steady state, substrate conversion rate and biomass production rate of the system vary during the cycle. An intermittent feed and decant regime results in alternating high low substrate (feast famine) conditions in the reactor. One of the most important...

Process technology changes

Process technology changes involve the installation of new processes and technology to minimise waste and increase efficiency. Examples of installations of new technology include Replacing batch pasteurisers with continuous process pasteurisers incorporating plate heat exchangers with less waste and counter current heat regeneration reducing energy consumption (UNEP 2000). Fully automated cleaning system in a milk processing plant to reduce water and energy usage e.g. Bonlac Foods, Australia...

Housekeeping

Improved housekeeping is based on improvements to work processes and proper maintenance, including preventing spills and wastage, and improved monitoring, training and inventory. Examples of improved housekeeping are Collect first flush of product changeovers and where possible blend back into the next product or dispose of as animal feed e.g. Dairy Farmers, Australia collects 500 L product day during changeovers, this is used for blending, with payback of 1 month (Prasad et al. 2004)....

Pretreatments to extraction

Intracellular oils can be difficult to extract from biomass due to the presence of intact cells. Cellular disruption greatly enhances the bioavailability of compounds and has been found to be necessary for recovering intracellular products from microalgae (Yongmanitchai and Ward, 1989 Wen and Chen, 2003 Ward and Singh, 2005). A number of physical techniques have been studied and reviewed, including the use of ultrasonifica-tion, high-pressure homogenizers and agitation of biomass in the...

Other technologies

Traditional extraction technologies including Soxhlet solvent extraction, steam distillation and hydro-distillation have been employed successfully for many applications in the food and pharmaceutical industry. These technologies have drawbacks in that they use toxic, flammable solvents that are in many cases being banned from food use. The techniques typically are time and energy consuming and often require further separation or cleanup. Many other innovative extraction technologies now exist...

Greenhouse gas emissions

The reduction of greenhouse gas emissions was one of the principal commitments made at the recent IDF World Dairy Summit (Begg 2005). Life cycle studies on greenhouse gas emissions for market milk in Sweden and Australia show that the bulk of greenhouse emissions occur at the farm, 87 in Sweden and 70 in Australia (Nicol 2004 Svenskmjolk 2004) (see Table 14.9). Farm emissions comprise methane from cows and nitrogen Table 14.7 Energy consumption for various dairy products (GJ tonne end product)....

Development of anaerobic biohydrogen production processes

Most continuous studies for hydrogen production have investigated hydrogen production using a completely mixed system. Although various organic loading rates have been investigated, conversion efficiencies have not been equal to the theoretical value of 0.467 L H2 g COD for acetic acid fermentation (Majizat et al., 1997 Lin and Chang, 1999 Fang and Liu, 2002). Some have tried to try increase hydrogen yields in a CSTR system by applying a vacuum to the head space of the reactor (Kataoka et al.,...