Thermal decomposition of fats and oils occurs when they are heated to high temperatures, such as during deep fat frying. This causes lipids to break down through hydrolysis, oxidation, and polymerization, deteriorating the oil quality. Trans fatty acids are formed as unsaturated fatty acids break down and change from cis to trans configurations. Consumption of trans fats is linked to increased risk of heart disease, diabetes, and obesity. Many food companies use trans fats because they have desirable qualities for food processing but they are now being restricted or banned in many places due to health concerns.
Water activity is the moisture content of the food which is available for microbial growth.By controlling water activity the food can be preserved for longer duration
Lecture 5 chemical preservation of foodDavid mbwiga
The document discusses various chemical preservatives that are added to foods to prevent spoilage from microorganisms and undesirable chemical changes, including traditional preservatives like salt and sugar, acids like benzoic and sorbic acid, gaseous preservatives like sulfur dioxide and carbon dioxide, and antioxidants. It provides details on the mechanisms of various preservatives and guidelines for their safe use to extend the shelf life of foods while maintaining quality and safety for consumption. Chemical preservatives are carefully regulated and tested to ensure they are used at appropriate levels and for intended purposes in specific foods.
The document discusses the process of making protein isolates and concentrates from various sources such as soy, whey, peanuts, and fish. Protein isolates have a very high protein content (over 90%) and are refined to remove carbohydrates and fiber. Protein concentrates contain some carbohydrates and have a protein content over 80%. Common methods for extracting and purifying proteins include isoelectric precipitation, alkaline extraction, and ultrafiltration. Specific examples of production processes are provided for whey protein isolates, fish protein isolates, peanut protein isolates, and soy protein isolates and concentrates.
The document discusses the functional properties of proteins in foods. It begins by defining functionality as any non-nutritive property that influences an ingredient's usefulness. It then identifies three main groups of functional properties: hydration properties related to protein-water interactions like solubility and viscosity; properties related to protein-protein interactions like gelation and dough formation; and surface properties involved in emulsification and foaming. Specific examples covered include the role of proteins in viscosity, gelation, emulsions, foams, and dough formation. The document concludes by noting how extrusion and enzymatic hydrolysis can alter soy protein properties.
Packaging has been used for thousands of years, originally using natural materials like skins and leaves. Four thousand years ago, sealed pottery jars were introduced to protect against rodents. One hundred years ago, packaging was rarely used in food industries but now is a significant part of food production, with continuous development of new packaging materials and equipment. Modified atmosphere packaging is a common technique that uses specialized machinery to flush out air and replace it with different gases or gas mixtures to provide longer shelf life and maintain food safety and quality by modifying the normal air composition. The major gases used are nitrogen, oxygen, and carbon dioxide in various combinations depending on the food and storage temperature.
Canning is the process of sealing foods in containers and sterilizing them through heat to allow for long storage. It was invented in France in 1804 by Appert and involves selecting high quality fresh fruits and vegetables, washing, cutting, blanching, filling containers, exhausting air, sealing, heat processing, cooling, and storing in a cool, dry place. The multi-step process preserves foods by killing microorganisms and preventing recontamination.
Water activity is the moisture content of the food which is available for microbial growth.By controlling water activity the food can be preserved for longer duration
Lecture 5 chemical preservation of foodDavid mbwiga
The document discusses various chemical preservatives that are added to foods to prevent spoilage from microorganisms and undesirable chemical changes, including traditional preservatives like salt and sugar, acids like benzoic and sorbic acid, gaseous preservatives like sulfur dioxide and carbon dioxide, and antioxidants. It provides details on the mechanisms of various preservatives and guidelines for their safe use to extend the shelf life of foods while maintaining quality and safety for consumption. Chemical preservatives are carefully regulated and tested to ensure they are used at appropriate levels and for intended purposes in specific foods.
The document discusses the process of making protein isolates and concentrates from various sources such as soy, whey, peanuts, and fish. Protein isolates have a very high protein content (over 90%) and are refined to remove carbohydrates and fiber. Protein concentrates contain some carbohydrates and have a protein content over 80%. Common methods for extracting and purifying proteins include isoelectric precipitation, alkaline extraction, and ultrafiltration. Specific examples of production processes are provided for whey protein isolates, fish protein isolates, peanut protein isolates, and soy protein isolates and concentrates.
The document discusses the functional properties of proteins in foods. It begins by defining functionality as any non-nutritive property that influences an ingredient's usefulness. It then identifies three main groups of functional properties: hydration properties related to protein-water interactions like solubility and viscosity; properties related to protein-protein interactions like gelation and dough formation; and surface properties involved in emulsification and foaming. Specific examples covered include the role of proteins in viscosity, gelation, emulsions, foams, and dough formation. The document concludes by noting how extrusion and enzymatic hydrolysis can alter soy protein properties.
Packaging has been used for thousands of years, originally using natural materials like skins and leaves. Four thousand years ago, sealed pottery jars were introduced to protect against rodents. One hundred years ago, packaging was rarely used in food industries but now is a significant part of food production, with continuous development of new packaging materials and equipment. Modified atmosphere packaging is a common technique that uses specialized machinery to flush out air and replace it with different gases or gas mixtures to provide longer shelf life and maintain food safety and quality by modifying the normal air composition. The major gases used are nitrogen, oxygen, and carbon dioxide in various combinations depending on the food and storage temperature.
Canning is the process of sealing foods in containers and sterilizing them through heat to allow for long storage. It was invented in France in 1804 by Appert and involves selecting high quality fresh fruits and vegetables, washing, cutting, blanching, filling containers, exhausting air, sealing, heat processing, cooling, and storing in a cool, dry place. The multi-step process preserves foods by killing microorganisms and preventing recontamination.
This document discusses carbohydrates, including their functions as an energy source, how they are broken down, and types such as starch, fiber, and modified starch. It also provides instructions for a task to design a macaroni and cheese product for children that is high in calcium, has a garnish, increases fiber content, and uses a roux sauce method.
Active packaging incorporates additives into packaging films or containers to maintain and extend the shelf life of food products. It includes oxygen scavengers, carbon dioxide generators, ethylene scavengers, and antimicrobial agents. Oxygen scavengers prevent food spoilage by chemically removing oxygen from packages through reactions with iron, ascorbic acid, or unsaturated fatty acids. Carbon dioxide generators and ethylene scavengers inhibit microbial growth and ripening to preserve freshness. Antimicrobial packaging prevents microbial growth through the release of compounds like ethanol or silver ions. Active packaging technologies are expected to grow significantly due to consumer demand for premium, safe, and convenient packaged foods.
Changes occur to fats during food processing and cooking. Heating fats can cause randomization of glyceride structure, dimer formation, cis-trans isomerization, and formation of conjugated fatty acids. Specific processes like hydrogenation, interesterification, and deodorization further impact fat composition. Deep frying is high heat cooking that promotes reactions like oxidation, leading to rancidity over time. Thermal properties like smoke point are important considerations for fat selection in cooking.
Dehydration is a method of food preservation that involves removing water from foods through the application of heat. This reduction in water content inhibits microbial growth and enzyme activity, extending the shelf life of foods. However, dehydration also causes deterioration in food quality attributes like texture, flavor, and nutrition. Various factors influence the dehydration process, and different equipment like cabinet dryers, tunnel dryers, and spray dryers are used depending on the type of food being dried.
Processing pulses through puffing, flaking, and milling into flour can improve their nutritive value by reducing anti-nutritional factors. Puffing exposes grains to high steam pressure which causes them to burst open and expand in size. Flaking involves partially cooking grains through steaming then pressing or rolling them into thin crispy flakes. Milling grains in plate, roller, or hammer mills produces pulses flours. Soaking, puffing, flaking, and milling techniques can increase the protein, fiber, and mineral content of pulses while decreasing compounds responsible for flatulence.
The document discusses smoking of meat. Smoking involves hanging meat in a smokehouse where hardwood logs or chips are burned, exposing the meat to smoke at 57°C for 18-24 hours. Over 300 compounds are extracted from wood smoke, including phenols, alcohols, organic acids, and hydrocarbons, which contribute to flavor, color, and preservation of the meat. Different types of wood impart varying flavors. Smoking can be cold, hot, or warm, affecting preservation and cooking of the meat. Liquid smoke provides an alternative method for smoking.
Modified atmosphere packaging (MAP) involves sealing food in packaging with different gas proportions than normal air to extend shelf life. Oxygen is reduced to limit microbial growth and oxidative deterioration while carbon dioxide and nitrogen inhibit microbes and prevent browning. The optimal gas mixture depends on the food and packaging material's gas permeability. MAP increases shelf life by slowing chemical and microbial changes in food compared to chilled storage alone.
Blanching is a heat treatment used prior to freezing, canning, or drying fruits and vegetables. It involves scalding produce in boiling water or steam to inactivate enzymes and microorganisms. Blanching helps preserve color, flavor, texture and nutrients. Key factors like product type, size, temperature, and heating method influence blanching time. It is a critical pre-treatment step but not a method of preservation on its own. Modern blanching techniques include steam, hot water, microwave, infrared and high-pressure methods.
This document discusses various methods of food concentration, including solar concentration, open kettles, flash evaporators, thin film evaporators, vacuum evaporators, freeze concentration, and ultra filtration and reverse osmosis. It also lists some commonly concentrated foods such as evaporated and sweetened condensed milks, fruit and vegetable juices, nectars, sugar syrups, flavored syrups, jams, jellies, and tomato paste. Additionally, it briefly introduces preservation by dehydration and mentions fruit juice powder.
This document discusses different types of browning reactions that can occur in food, including enzymatic and non-enzymatic browning. It describes two main types of non-enzymatic browning reactions: caramelization which occurs when sugars are heated and Maillard browning which involves sugars and amino acids. Enzymatic browning is caused by polyphenol oxidase enzymes and phenolic compounds interacting with oxygen. Methods to prevent enzymatic browning discussed include maintaining an acid pH, using sulphur or antioxidants, reducing oxygen contact, and denaturing enzymes through blanching.
Freezing food involves lowering the temperature so that water inside the food freezes into ice crystals. This process is known as freezing and involves three stages: cooling the food below its freezing point, water changing state to form ice crystals, and further cooling to the freezer temperature for preservation. The rate of freezing impacts crystal size, with fast freezing producing smaller crystals and maintaining food quality better than slow freezing. Proper frozen storage is also important to prevent quality loss from physical, chemical, biochemical, and microbial changes over time. Maintaining temperatures lower than -18°C can help secure food quality and avoid issues like recrystallization according to the time, temperature, tolerance theory of frozen food storage.
Hurdle technology for food preservationDeepak Verma
This document discusses hurdle technology, which uses a combination of preservation methods at optimal levels to inhibit microorganisms without compromising food quality. It explains that hurdle technology combines physical hurdles like heat treatment, freezing or modified atmosphere with physic-chemical hurdles like low pH, salt or preservatives. Some examples given are pickles which use acid and salt, and sausages which employ smoke, salt and preservatives. The advantages of hurdle technology are maintaining food safety, quality and nutrition while allowing for minimally processed foods.
This document discusses various methods for canning and preserving meat, including the canning process, types of containers used, thermal processing, and potential causes of spoilage. The key steps in canning include preparation of raw materials, filling containers, exhausting air and sealing, thermal processing to achieve commercial sterility, cooling, labeling and storage. Canned foods can potentially spoil due to microbial growth if underprocessed or due to chemical reactions. Methods for preserving meat also include irradiation and use of antibiotics.
Characterstics of fats and oil & processingjas maan
This document provides an overview of fats and oils, including their chemical structure, properties, processing, and uses. It discusses the differences between fats and oils, noting that fats remain solid at room temperature while oils remain liquid. The document covers the chemical composition of fats and oils as triglycerides, and describes various physical properties like melting point, crystallization, and emulsification. Key processing steps are summarized, including extraction, refining through degumming and neutralization, and bleaching and deodorization.
This document discusses various techniques for scavenging oxygen, ethylene, and carbon dioxide in food packaging. It begins by introducing the concepts of active and intelligent packaging designed to interact with food products. It then provides details on common scavenging technologies for each gas, including iron-based and ascorbic acid oxygen scavengers, potassium permanganate and activated carbon ethylene scavengers, and calcium oxide and hydroxide carbon dioxide scavengers/absorbers. Examples of commercial scavenging products are also given. The document concludes by emphasizing dual scavengers that can remove both oxygen and carbon dioxide.
Ultra High Temperature Processing of Food ProductsSourabh Bhartia
The document discusses ultra high temperature (UHT) processing of food products. UHT processing involves heating food to 135°C for 2-5 seconds to kill microorganisms and spores. This allows for longer shelf life without refrigeration. There are two main methods - direct heating which applies steam directly to the food, and indirect heating which uses a partition between the food and steam. Indirect heating includes plate heat exchangers, tubular heat exchangers, and scraped surface heat exchangers. UHT processing offers benefits like longer shelf life and packaging flexibility but requires complex sterile processing equipment.
Freezing helps to Inhibit the growth of microorganisms hence help in preservation of foods. So, freezing is a very easy and effective method for the preservation of fruits and vegetables and to retain them for longer duration.
There are two main methods of freezing food commercially - fast freezing at temperatures below -25°C which forms small ice crystals, and slow freezing above -24°C which forms larger crystals that can damage the food. Common freezing techniques include air blast, fluidized bed, plate or belt, immersion, and cryogenic freezing using liquid nitrogen or carbon dioxide. The freezing method chosen depends on factors like the food quality desired, type and shape of the food, package used, required flexibility, and costs. Equations can be used to estimate freezing times based on properties of the food and freezing conditions.
Water activity and types of food based on water activitySaptadeep Sanyal
Water activity is a measure of available water in a food and is important because it determines microbial growth. It is defined as the ratio of vapor pressure of water in a food to vapor pressure of pure water at the same temperature. Foods with water activities below 0.6 inhibit mold growth, increasing shelf life. Controlling water activity through addition of solutes like salt or sugar allows some foods to be stored without refrigeration as intermediate moisture foods.
The document discusses the science of oil frying, including the chemical reactions that occur when foods are deep fried such as hydrolysis, oxidation, and polymerization. These chemical changes impact properties of both the oil like acid value and polar compounds as well as the fried foods through changes in moisture, fat content, and formation of new compounds. Factors like frying time and temperature, oil composition, and food composition influence the degree of chemical degradation during the frying process.
The document discusses the RUCO (Repurpose Used Cooking Oil) initiative launched by FSSAI and BDAI to collect used cooking oil from food businesses and convert it to biodiesel. It outlines the harmful effects of reusing cooking oil, how polar compounds are created when oil is heated, and regulations introduced by FSSAI limiting reuse. The RUCO app allows restaurants to request pickup of used oil, which is supplied to biodiesel manufacturers. The initiative aims to address improper disposal of used cooking oil and provide a feasible feedstock for biodiesel production.
This document discusses carbohydrates, including their functions as an energy source, how they are broken down, and types such as starch, fiber, and modified starch. It also provides instructions for a task to design a macaroni and cheese product for children that is high in calcium, has a garnish, increases fiber content, and uses a roux sauce method.
Active packaging incorporates additives into packaging films or containers to maintain and extend the shelf life of food products. It includes oxygen scavengers, carbon dioxide generators, ethylene scavengers, and antimicrobial agents. Oxygen scavengers prevent food spoilage by chemically removing oxygen from packages through reactions with iron, ascorbic acid, or unsaturated fatty acids. Carbon dioxide generators and ethylene scavengers inhibit microbial growth and ripening to preserve freshness. Antimicrobial packaging prevents microbial growth through the release of compounds like ethanol or silver ions. Active packaging technologies are expected to grow significantly due to consumer demand for premium, safe, and convenient packaged foods.
Changes occur to fats during food processing and cooking. Heating fats can cause randomization of glyceride structure, dimer formation, cis-trans isomerization, and formation of conjugated fatty acids. Specific processes like hydrogenation, interesterification, and deodorization further impact fat composition. Deep frying is high heat cooking that promotes reactions like oxidation, leading to rancidity over time. Thermal properties like smoke point are important considerations for fat selection in cooking.
Dehydration is a method of food preservation that involves removing water from foods through the application of heat. This reduction in water content inhibits microbial growth and enzyme activity, extending the shelf life of foods. However, dehydration also causes deterioration in food quality attributes like texture, flavor, and nutrition. Various factors influence the dehydration process, and different equipment like cabinet dryers, tunnel dryers, and spray dryers are used depending on the type of food being dried.
Processing pulses through puffing, flaking, and milling into flour can improve their nutritive value by reducing anti-nutritional factors. Puffing exposes grains to high steam pressure which causes them to burst open and expand in size. Flaking involves partially cooking grains through steaming then pressing or rolling them into thin crispy flakes. Milling grains in plate, roller, or hammer mills produces pulses flours. Soaking, puffing, flaking, and milling techniques can increase the protein, fiber, and mineral content of pulses while decreasing compounds responsible for flatulence.
The document discusses smoking of meat. Smoking involves hanging meat in a smokehouse where hardwood logs or chips are burned, exposing the meat to smoke at 57°C for 18-24 hours. Over 300 compounds are extracted from wood smoke, including phenols, alcohols, organic acids, and hydrocarbons, which contribute to flavor, color, and preservation of the meat. Different types of wood impart varying flavors. Smoking can be cold, hot, or warm, affecting preservation and cooking of the meat. Liquid smoke provides an alternative method for smoking.
Modified atmosphere packaging (MAP) involves sealing food in packaging with different gas proportions than normal air to extend shelf life. Oxygen is reduced to limit microbial growth and oxidative deterioration while carbon dioxide and nitrogen inhibit microbes and prevent browning. The optimal gas mixture depends on the food and packaging material's gas permeability. MAP increases shelf life by slowing chemical and microbial changes in food compared to chilled storage alone.
Blanching is a heat treatment used prior to freezing, canning, or drying fruits and vegetables. It involves scalding produce in boiling water or steam to inactivate enzymes and microorganisms. Blanching helps preserve color, flavor, texture and nutrients. Key factors like product type, size, temperature, and heating method influence blanching time. It is a critical pre-treatment step but not a method of preservation on its own. Modern blanching techniques include steam, hot water, microwave, infrared and high-pressure methods.
This document discusses various methods of food concentration, including solar concentration, open kettles, flash evaporators, thin film evaporators, vacuum evaporators, freeze concentration, and ultra filtration and reverse osmosis. It also lists some commonly concentrated foods such as evaporated and sweetened condensed milks, fruit and vegetable juices, nectars, sugar syrups, flavored syrups, jams, jellies, and tomato paste. Additionally, it briefly introduces preservation by dehydration and mentions fruit juice powder.
This document discusses different types of browning reactions that can occur in food, including enzymatic and non-enzymatic browning. It describes two main types of non-enzymatic browning reactions: caramelization which occurs when sugars are heated and Maillard browning which involves sugars and amino acids. Enzymatic browning is caused by polyphenol oxidase enzymes and phenolic compounds interacting with oxygen. Methods to prevent enzymatic browning discussed include maintaining an acid pH, using sulphur or antioxidants, reducing oxygen contact, and denaturing enzymes through blanching.
Freezing food involves lowering the temperature so that water inside the food freezes into ice crystals. This process is known as freezing and involves three stages: cooling the food below its freezing point, water changing state to form ice crystals, and further cooling to the freezer temperature for preservation. The rate of freezing impacts crystal size, with fast freezing producing smaller crystals and maintaining food quality better than slow freezing. Proper frozen storage is also important to prevent quality loss from physical, chemical, biochemical, and microbial changes over time. Maintaining temperatures lower than -18°C can help secure food quality and avoid issues like recrystallization according to the time, temperature, tolerance theory of frozen food storage.
Hurdle technology for food preservationDeepak Verma
This document discusses hurdle technology, which uses a combination of preservation methods at optimal levels to inhibit microorganisms without compromising food quality. It explains that hurdle technology combines physical hurdles like heat treatment, freezing or modified atmosphere with physic-chemical hurdles like low pH, salt or preservatives. Some examples given are pickles which use acid and salt, and sausages which employ smoke, salt and preservatives. The advantages of hurdle technology are maintaining food safety, quality and nutrition while allowing for minimally processed foods.
This document discusses various methods for canning and preserving meat, including the canning process, types of containers used, thermal processing, and potential causes of spoilage. The key steps in canning include preparation of raw materials, filling containers, exhausting air and sealing, thermal processing to achieve commercial sterility, cooling, labeling and storage. Canned foods can potentially spoil due to microbial growth if underprocessed or due to chemical reactions. Methods for preserving meat also include irradiation and use of antibiotics.
Characterstics of fats and oil & processingjas maan
This document provides an overview of fats and oils, including their chemical structure, properties, processing, and uses. It discusses the differences between fats and oils, noting that fats remain solid at room temperature while oils remain liquid. The document covers the chemical composition of fats and oils as triglycerides, and describes various physical properties like melting point, crystallization, and emulsification. Key processing steps are summarized, including extraction, refining through degumming and neutralization, and bleaching and deodorization.
This document discusses various techniques for scavenging oxygen, ethylene, and carbon dioxide in food packaging. It begins by introducing the concepts of active and intelligent packaging designed to interact with food products. It then provides details on common scavenging technologies for each gas, including iron-based and ascorbic acid oxygen scavengers, potassium permanganate and activated carbon ethylene scavengers, and calcium oxide and hydroxide carbon dioxide scavengers/absorbers. Examples of commercial scavenging products are also given. The document concludes by emphasizing dual scavengers that can remove both oxygen and carbon dioxide.
Ultra High Temperature Processing of Food ProductsSourabh Bhartia
The document discusses ultra high temperature (UHT) processing of food products. UHT processing involves heating food to 135°C for 2-5 seconds to kill microorganisms and spores. This allows for longer shelf life without refrigeration. There are two main methods - direct heating which applies steam directly to the food, and indirect heating which uses a partition between the food and steam. Indirect heating includes plate heat exchangers, tubular heat exchangers, and scraped surface heat exchangers. UHT processing offers benefits like longer shelf life and packaging flexibility but requires complex sterile processing equipment.
Freezing helps to Inhibit the growth of microorganisms hence help in preservation of foods. So, freezing is a very easy and effective method for the preservation of fruits and vegetables and to retain them for longer duration.
There are two main methods of freezing food commercially - fast freezing at temperatures below -25°C which forms small ice crystals, and slow freezing above -24°C which forms larger crystals that can damage the food. Common freezing techniques include air blast, fluidized bed, plate or belt, immersion, and cryogenic freezing using liquid nitrogen or carbon dioxide. The freezing method chosen depends on factors like the food quality desired, type and shape of the food, package used, required flexibility, and costs. Equations can be used to estimate freezing times based on properties of the food and freezing conditions.
Water activity and types of food based on water activitySaptadeep Sanyal
Water activity is a measure of available water in a food and is important because it determines microbial growth. It is defined as the ratio of vapor pressure of water in a food to vapor pressure of pure water at the same temperature. Foods with water activities below 0.6 inhibit mold growth, increasing shelf life. Controlling water activity through addition of solutes like salt or sugar allows some foods to be stored without refrigeration as intermediate moisture foods.
The document discusses the science of oil frying, including the chemical reactions that occur when foods are deep fried such as hydrolysis, oxidation, and polymerization. These chemical changes impact properties of both the oil like acid value and polar compounds as well as the fried foods through changes in moisture, fat content, and formation of new compounds. Factors like frying time and temperature, oil composition, and food composition influence the degree of chemical degradation during the frying process.
The document discusses the RUCO (Repurpose Used Cooking Oil) initiative launched by FSSAI and BDAI to collect used cooking oil from food businesses and convert it to biodiesel. It outlines the harmful effects of reusing cooking oil, how polar compounds are created when oil is heated, and regulations introduced by FSSAI limiting reuse. The RUCO app allows restaurants to request pickup of used oil, which is supplied to biodiesel manufacturers. The initiative aims to address improper disposal of used cooking oil and provide a feasible feedstock for biodiesel production.
Fatty acids are the basic units of fat composed of hydrocarbon chains with a carboxyl group at one end. They can be saturated, containing only single bonds between carbon atoms, or unsaturated with one or more double bonds. Saturated fatty acids are solid at room temperature due to close packing, while unsaturated fatty acids are usually liquid due to kinks in their structure. Fatty acids are produced via hydrolysis of triglycerides from plants and animals, which involves splitting the triglyceride into glycerol and three fatty acid molecules. The fatty acids can then be purified by distillation and fractionation.
1683394189120_1683394188693_DC 513 Assignments -chemical reaction of milk lip...ShanthiN6
Chemical reactions involved autoxidation of milk fat are grouped in to three categories. viz. intiation, propogation and termination. The initial step in the autoxidation of unsaturated fatt acid and their ester is the formation of free radical. In the case of monounsaturated and non conjugated polyene fatty acids the reaction is initiated by the removal of hydrogen atom from the methylene group of adjacent to the double bond. The resulting free radical stabilized by resonance adds oxygen to form peroxide containing free radicals these in turn react with another mole of unsaturated compound to produce two isomerichydroperoxides
The document discusses research on the effects of high-temperature cooking oils used for fried foods. Chemical analysis found that the number of acids increases in oils absorbed in fried products, likely due to moisture and cooking temperatures breaking down oils. The number of iodine decreases with repeated heating, indicating changes to oil composition. Infrared spectroscopy detected trans fatty acid isomers form when oils are heated, which can increase health risks like heart disease. The density and refractive index of oils increased over time spent cooking, showing polymerization and composition changes.
Rancidification is the process of complete or incomplete oxidation or hydrolysis of fats and oils when exposed to air, light, or moisture or by bacterial action, resulting in unpleasant taste and odor. Specifically, it is the hydrolysis or autoxidation of fats into short-chain aldehydes and ketones, which are objectionable in taste and odor. When these processes occur in food, undesirable odors and flavors can result.
This document discusses fats and oils, including their similarities and differences, classifications, chemical composition, physical properties, reactions, and rancidity. Key points include:
- Fats are solid at room temperature while oils are liquid. Both are triglycerides made of glycerol and fatty acid chains.
- Fats and oils can be classified by appearance, source (plant vs. animal), and culinary use.
- They provide calories and essential fatty acids. Unsaturated fats may improve cholesterol levels while saturated fats can increase cholesterol.
- Chemical reactions include hydrolysis, oxidation, hydrogenation, and others involving ester linkages and double bonds.
- Physical properties
This document summarizes a study conducted by Dr. Sapna Johnson and Dr. Nirmali Saikia at the Centre for Science and Environment in India on the fatty acid profiles of edible oils and fats commonly consumed in India. The study aimed to determine the saturated, unsaturated, and trans fatty acid content of refined edible oils, vanaspati, ghee and butter samples using approved analytical methods. The document provides background information on fats and oils, fatty acid classification and health effects of trans fats to contextualize the study. It also describes the materials, methods, results and conclusions of the analysis of fatty acid profiles in the oil and fat samples.
This document summarizes a study conducted by Dr. Sapna Johnson and Dr. Nirmali Saikia at the Centre for Science and Environment in India on the fatty acid profiles of commonly consumed edible oils and fats in India. The study aimed to determine the saturated, unsaturated, and trans fatty acid content of refined edible oils, vanaspati, ghee and butter samples using gas chromatography. The document provides background on fats and oils, fatty acids, essential fatty acids, the edible oil industry in India, hydrogenation and trans fats, and health risks of trans fats. It also describes the materials and methods used in the study as well as presents and discusses the results.
This document provides information about fats, oils, and their properties. It defines fats and oils as lipids that are saponifiable (containing ester groups) and made up of triglycerides consisting of glycerol bonded to three fatty acid chains. The document discusses the hydrolysis, hydrogenation, saponification, and rancidification reactions of fats and oils. It also defines analytical values used to characterize fats and oils such as saponification value, iodine value, and acid value. Sources and extraction methods of fats and oils from plants and animals are also summarized.
this is chemistry related to food. rancidity - a phenomena of oxidation of oils and fats which leads to their foul smell and taste. it can be prevented in homes by keeping foods containing oils and fats, in air tight containers. packets of chip are filled with nitrogenous gas to prevent rancidity. go on reading this ppt that I had prepared as my holiday homework for chemistry, it is very informative even if you just want to know about the phenomena. - mansvini
This document discusses oils and fats. It explains that oils are liquid at room temperature due to unsaturated fatty acid chains, while fats are solid due to saturated chains. Key processes mentioned include hydrogenation, which converts unsaturated oils to saturated fats, and hydrolysis, which breaks triglycerides into glycerol and fatty acids. Fatty acid oxidation and lipoproteins that transport fats and cholesterol in the blood are also summarized.
Fats and oils are triglycerides composed of fatty acid chains bonded to a glycerol backbone. They undergo various chemical reactions including hydrolysis, hydrogenation, hydrogenolysis, and saponification. The properties of fats and oils can be analyzed using various values such as acid value, saponification value, iodine value, and Reichert Meissl value. These values provide information about the fatty acid composition and purity of the sample being tested.
Rancidity is a common problem in rendered animal products. It can have detrimental effects on both the quality and safety of the product.
It is caused by the oxidation of fats and oils, leading to the formation of harmful compounds such as free radicals and hydroperoxides.
The best way to prevent rancidity is through proper storage, packaging, and handling techniques, as well as the use of antioxidants to slow down the oxidation process. It is important for manufacturers and consumers to be aware of the potential for rancidity in rendered animal products and take the necessary precautions to ensure the safety and quality of the product.
Rancidity testing is essential in the feed industry, as a key indicator of product quality and shelf life.
It is conducted to determine the level of oxidation in samples of feed or feed ingredients
Rancidity is a chemical change that results in an unpleasant odour and taste in a fat or oil.
Types of Rancidity
Hydrolytic rancidity
Oxidative rancidityOil becomes rancid due to the decomposition of fats it contains
Milk turns rancid due to not heating it in the humid atmosphere.
Butter changes its smell and taste when it is kept in an open atmosphere for a longer duration.
Hydrolytic rancidity develops due to the presence of moisture and by growth of microorganisms in the fat.
The microorganisms secrete lipases which split the triglycerides into glycerol and fatty acids.
Hydrolytic rancidity of butter releases volatile butyric acid which gives the bad odour and taste.
Oxidative rancidity occurs in oils and fats containing unsaturated fatty acids due to exposure to air.
Unsaturated fatty acids are converted into hydroperoxides, which break down into volatile aldehydes, esters, alcohols, ketones, and hydrocarbons, some of which have disagreeable odours.
Fats contaminated with enzymes like lipase undergo partial hydrolysis and oxidation of unsaturated fatty acids at the double bonds.
This is even brought about by the atmospheric moisture and temperature. Due to this, there is release of hydrogen peroxide giving a bad odour and taste to the fat.
Rancidity can be prevented by antioxidants like vitamin E, vitamin C, phenols, hydroquinone’s, etc.
Rancidity Process: Rancidity happens in food products that have oil and fatty acids in them. Any substance turns rancid in basically three steps:
I. Initiation Reaction: Initiation reaction leads to the formation of radicals on the food substances because of external factors like heat and air that stimulates this reaction. A radical is an atom molecule or ion that has an unpaired electron. These unpaired electrons make radicals very reactive chemical substances.
RH ⇒ R- + H+
Propagation Reaction: In this step, oxygen present in the atmosphere gives rise to peroxides. These peroxides react further with unsaturated fatty acids and then produce new radicals.
Termination Reaction: In the third stage, two radicals combine together to form a new single bond.
This document discusses fatty acids, including their classification, properties, and functions. It describes that fatty acids are classified as saturated or unsaturated depending on whether they contain double bonds. Unsaturated fatty acids are further broken down into mono- and polyunsaturated. Fatty acids also vary in length and whether they are essential or non-essential to the human body. The document outlines the physical and chemical properties of fatty acids and discusses their roles in energy storage, cell signaling, and as structural components of cell membranes.
The document discusses lipids and fatty acids. It defines lipids as organic substances that are insoluble in water but soluble in organic solvents. Lipids are classified into simple, compound, derived and miscellaneous lipids. Fatty acids are the most common components of lipids in the body. They are aliphatic carboxylic acids with hydrocarbon side chains. Saturated and unsaturated fatty acids occur naturally. Phospholipids are an important class of compound lipids that form structural components of biological membranes and are involved in various metabolic functions. The most abundant phospholipid is lecithin, which contains phosphoric acid esterified to glycerol and choline.
The document discusses lipids and their properties. It defines lipids as esters of fatty acids and glycerol. It provides the chemical formulas of various saturated and unsaturated fatty acids. It also discusses the major vegetable oils used in food like soybean, palm, rapeseed, sunflower, and coconut oils. It provides data on the lipid content and calorie content of various foods. It explains the process of saponification where triglycerides are hydrolyzed with a base to form soap, releasing glycerol. It discusses the physical and chemical properties of oils and fats important for different uses.
Similar to Thermal decomposition of fats & oil (20)
Heritage Conservation.Strategies and Options for Preserving India HeritageJIT KUMAR GUPTA
Presentation looks at the role , relevance and importance of built and natural heritage, issues faced by heritage in the Indian context and options which can be leveraged to preserve and conserve the heritage.It also lists the challenges faced by the heritage due to rapid urbanisation, land speculation and commercialisation in the urban areas. In addition, ppt lays down the roadmap for the preservation, conservation and making value addition to the available heritage by making it integral part of the planning , designing and management of the human settlements.
The Menu affects everything in a restaurant; as our friend and FCSI consultant Bill Main says, “The Menu is your blueprint for profitability.”
Let’s start with the segment. What will be your marketing and brand positioning? It depends on what menu items you serve. What type of cooking methods and equipment will you use? GUEST EXPERIENCE = FACILITY (Space) DESIGN + MENU + SERVPOINTS™
W.H. Bender & Associates
408-784-7371
whb@whbender.com
www.whbender.com
San Jose, California
A Review on Recent Advances of Packaging in Food IndustryPriyankaKilaniya
Effective food packaging provides number of purposes. It functions as a container to hold and transport the food product, as well as a barrier to protect the food from outside contamination such as water, light, odours, bacteria, dust, and mechanical damage by maintaining the food quality. The package may also include barriers to keep the product's moisture content or gas composition consistent. Furthermore, convenience is vital role in packaging, and the desire for quick opening, dispensing, and resealing packages that maintain product quality until fully consumed is increasing. To facilitate trading, encourage sales, and inform on content and nutritional attributes, the packaging must be communicative. For storage of food there is huge scope for modified atmosphere packaging, intelligent packaging, active packaging, and controlled atmosphere packaging. Active packaging has a variety of uses, including carbon dioxide absorbers and emitters, oxygen scavengers, antimicrobials, and moisture control agents. Smart packaging is another term for intelligent packaging. Edible packaging, self-cooling and self-heating packaging, micro packaging, and water-soluble packaging are some of the advancements in package material.
Cacao, the main component used in the creation of chocolate and other cacao-b...AdelinePdelaCruz
Cacao, the main component used in the creation of chocolate and other cacao-based products is cacao beans, which are produced by the cacao tree in pods. The Maya and Aztecs, two of the earliest Mesoamerican civilizations, valued cacao as a sacred plant and used it in religious rituals, social gatherings, and medical treatments. It has a long and rich cultural history.
Panchkula offers a wide array of dining experiences. From traditional North Indian flavors to global cuisine, the city’s restaurants cater to every taste bud. Let’s dive into some of the best restaurants in Panchkula
NANOTECHNOLOGY IN FOOD PACKAGING (FOOD TECHNOLOGY)
Thermal decomposition of fats & oil
1. THERMAL DECOMPOSITION OF FATS & OIL AND FLAVOUR REVERSION
DEPARTMENT OF FOOD ENGINEERING & TECHNOLOGY
Sant Longowal Institute of Engineering & Technology
Longowal,Sangrur-148106 (Punjab)
ANKIT KUMAR
ankitvatsya@gmail.com
+91-8699028994
2. INTRODUCTION:-
Fats and oils belong to group of biological substance called lipids.
Lipids are biological chemical that do not dissolve in water.
Fats are solid at room temperature whereas oil is liquid at Room temperature
.
Basically oil and fats are mixture of triglycerides.
When 3 fatty acids are combined with one glycerol molecule ,then it will
called triglyceride.
Saturated fatty acids have all predominantly single bonds whereas
unsaturated fatty acids have double bond.
Saturated fatty acids are generally Solid at room temperature whereas
unsaturated fatty acids are liquid at room temperature.
3. THERMAL DECOMPOSITION:-
Thermal decomposition, or thermolysis, is a chemical decomposition caused
by heat.
The decomposition temperature of a substance is the temperature at which
the substance chemically decomposes.
A reaction in which a substance is broken down into 2 or more substances
by heat.
An example is the breakdown of calcium carbonate into carbon dioxide
and calcium oxide.
The reaction is usually endothermic as heat is required to break chemical
bonds in the compound undergoing decomposition.
An example is when baking soda (sodium bicarbonate) is heated-
2NaHCO3(s)→CO2(g)+H2O(g)+Na2CO3(s)
4. THERMAL DECOMPOSITION OF FATS & OIL:-
High temperature used in frying causes lipids to undergo a variety of chemical and
physical changes due to thermal decomposition.
During deep-frying, the fat/oil is continuously exposed to elevated temperatures in
the presence of air and undergoes hydrolysis, oxidation and polymerisation, resulting
in deterioration in quality, thereby causing changes in not only the sensory but also
the nutritional properties.
Frying is also considered as a contributory factor leading to trans fatty acid (TFA)
formation, which is believed to be a product of partial hydrogenation.
The chemical mechanism of thermal oxidation is principally the same as the
autoxidation mechanism, but the thermal oxidation rate is faster than the
autoxidation rate.
the temperature dependence was investigated for the development of volatile
lipid oxidation products in in vegetable oils.
From a nutritional point of view, it should be taken into account that oils with high
amounts of saturated fatty acids and fats containing trans fatty acids are less
desirable for good health
5. Cont….
Deep-fat frying decreases the unsaturated fatty acids and increases polar
material.
Many methods have been used for determination of fat deterioration during
frying. They include methods for assessment of peroxide value, iodine value
dienes, fatty acids, polar components etc.
For the quality control of frying fats or oils the determination of total polar
parts is an approved standard method.
Heating/frying also increased the saturated fatty acids and decreased cis-
unsaturated fatty acids.
Metabolic studies have shown that TFAs increase low-density lipoprotein
cholesterol (LDL-c) and decrease high-density lipoprotein cholesterol (HDL-c)
levels, increasing the risk of cardiovascular diseases.
Furthermore, there is a growing concern that the risk for type 2 diabetes also
increases with TFA consumption
6. Chemical changes involved in thermal degradation of oils:-
1.HYDROLYSIS:-
))Hydrolysis is believed to be the first reaction generating detectable products
during frying, which causes major production of free fatty acids.
)) Depending on the extent of hydrolysis, products are fatty acids and,
progressively, diacylglycerols, monoacylglycerols, and glycerol .
))Chromatographic analysis of frying oils with high levels of free fatty acids
demonstrated that formation of monoacylglycerols is minimal.
))Although hydrolysis is one of the simplest reactions, previous research has
produced.
)) Some authors found hydrolysis to be the most important reaction during frying,
based on detection of high levels of free fatty acids and diacylglycerols , while
others found fatty acids to be minimal compared to other degradation products,
despite high water contents in the ood being fried.
7. Cont…
2.oxidation:-
)) Because the oxygen present in deep-frying reacts with oils, thermal oxidation has
been proposed to arise from the same reactions as in lipid autoxidation, but
accelerated by Arrhenius kinetics where the rate is doubledfor every 10 degrees
increase in temperature.
)) In the initiation stage, an alkyl radical (R ) is formed.
))In the propagation stage, oxygen adds to the alkyl radical to form peroxyl radicals
. these radicals, in turn, abstract hydrogens from other molecules to yield
hydroperoxides(ROOH) and a new radicals that react with oxygen to start a new
cycle and propagate the reaction chain. The hydroperoxide intermediates are not
stable, but are decomposed by heat to yield reactive hydroxyl radicals (HO ) plus
alkoxyl radicals that both abstract H’s to propagate and accelerate the oxidation
chain and undergo reactions to produce varied products.
)) Reactions are terminated when radicals react with each other to produce non-
radical compounds, either volatile or non-volatile, or when alkoxyl radical
8. Cont…..
3.polymerization:-
)) All commonly used fats and particularly those high in polyunsaturated fatty
acids tend to form larger molecules (known broadly as polymers) when heated
under extreme conditions of temperature and time. Under normal processing and
cooking conditions, polymers are formed. Although the polymerization process is
not completely understood, it is believed that polymers in fats and oils arise by
formation of either carbon-to-carbon bonds or oxygen bridges between
molecules. When an appreciable amount of polymer is present, there is a marked
increase in viscosity.
)) polymerizations are particularly facilitated by high temperatures. Dimerization
and polymerization occurs in three ways: 1) radical recombination,2) addition of
radicals to double bonds, and 3) Diels-Alder reactions, a reaction between a
double bond and a conjugated diene .
9. Factors affecting frying oil quality :-
1. Fatty acid (FA) composition :-
)) The common sense notion that oils composed of polyunsaturated fatty acids
should have lower frying stability than those composed of monounsaturated and
saturated fatty acids has been supported by many studies .
)) Isomers geometry also affect oxidation by altering accessibility of H atoms,
with cis fatty acids oxidize more readily than trans fatty acids.
2.FRYING CONDITION:-
)) Long time frying results in accumulation of a wide range ofoxidation products
including free fatty acids , polar compounds, dimers and polymers , most at high
levels.
)) Intermittent frying generally causesmore serious degradation than continuous
frying due to increased oxygen solubilization of oxygen in the oil during the
cooling period
10. CONT....
3.OXYGEN:-
)) Effects of oxygen on frying quality of oils have been studied for decades.
Ratesof change in viscosity and titratableacidity were found to be directly
proportional to the degree of exposure of fat surface to oxygen
4.WATER:-
)) Foods complicate the frying process in several ways. One of the most
important aspects is continuousrelease of water from food into oil. The released
moisture agitates the oil and promotes hydrolysis.
)) Moisture also catalyzed production of off-flavors in different kinds of frying
oils [60]. However, adding lower amounts of water (e.g. 0.7%) was protective.
This protection was attributed
11. TRANS FATTY ACIDS:-
Trans fatty acids are fatty acids that contain at least one double bond in
the trans configuration.
Dietary trans fatty acids occur naturally in meat and dairy products as a result
of anaerobic bacterial fermentation in ruminant animals.
Trans fatty acids are also created when liquid vegetable or fish oil is
hydrogenated; this is frequently done to increase their plasticity and
chemical stability for subsequent food processing.
During the hydrogenation process, some of the naturally occurring cis double
bonds in the vegetable oil fatty acids are changed to trans double bonds, so
that the resulting trans fatty acids resemble saturated fats more than
unsaturated fats.
Trans fatty acids are isomers of the normal cis fatty acids, produced when
PUFAs are hydrogenated, such as in the production of margarine and
vegetable shortening.
Trans fatty acids are manufactured fats created during a process called
hydrogenation, which is aimed at stabilizing polyunsaturated oils to prevent
them from becoming rancid and to keep them solid at room temperature.
12. Why do some companies use trans fats?
))Trans fats are easy to use, inexpensive to produce and last a long
time. Trans fats give foods a desirable taste and texture. Many restaurants and
fast-food outlets use trans fats to deep-fry foods because oils with trans fats can
be used many times in commercial fryers. Several countries (e.g., Denmark,
Switzerland, and Canada) and jurisdictions (California, New York City, Baltimore,
and Montgomery County, MD) have reduced or restricted the use of trans fats in
food service establishment.
)) Trans fats can be found in many foods – including fried foods like doughnuts,
and baked goods including cakes, pie crusts, biscuits, frozen pizza, cookies,
crackers, and stick margarines and other spreads.
13. HEALTH RISK:-
The primary health risk identified for trans fat consumption is an elevated
risk of coronary artery disease.
There is a growing concern that the risk of type 2 diabetes increases with
trans fat consumption.
Research indicates that trans fat may increase weight gain and abdominal
fat, despite a similar caloric intake.(Obesity)
Each 2% increase in the intake of energy from trans unsaturated fats, as
opposed to that from carbohydrates, was associated with a 73% greater risk of
ovulatory infertility in women.
Intake of both trans fats and saturated fats promote the development of
Alzheimer disease.
14. FLAVOUR REVERSION IN FATS & OIL
FlAVOR reversion in fats is probably defined most satisfactorily as the
appearance of objectionable flavor from less oxidation than is required to
produce true rancidity.
The degree to which reversion and rancidity are separated in terms of oxygen
absorbed by the fat is widely different for different fats.
There are some fats,however, including particularly fish oils and vegetable
oils containing linolenic acid, which revert with extremely slight oxidation.
It is almost impossible to prepare edible products from such fats and get
them to the consumer before they have suffered some loss of palatability.