Grandma called the food chemist because her meringue was flat instead of fluffy. The document discusses how egg whites form stable foams and what factors can affect foaming properties. It describes how proteins in egg whites stabilize foam by lowering surface tension and forming elastic films. The experiment examines how sugar, pH, salt, and other contaminants impact foam production and stability by separating egg whites, adjusting pH, pasteurizing, whipping to form foam, and measuring foam properties over time.
The limited availability of durum wheat and its relatively high price induce the search for alternatives that help to save costs while maintaining quality. The addition of vital wheat gluten is a viable but expensive method, and the application of hydrocolloids such as guar gum is limited to certain applications, e.g. instant noodle flour. The improving effect of specific emulsifiers and the recently discovered beneficial action of certain enzymes will be the subject of this article.
The document discusses the structure and composition of eggs. It describes the commercial evaluation of eggs based on weight, grade, and interior quality assessed by candling. Methods for research evaluation include measuring albumen height using a micrometer or caliper. During storage, egg quality decreases as the air cell increases in size, yolk enlarges, white thins, and odor/flavor deteriorates. Proper storage temperature and humidity can help maintain quality. Eggs function as coagulants, emulsifiers, and foaming agents in foods. Processed eggs are marketed in refrigerated, dried, and frozen forms to extend shelf life.
This document discusses how starch is impacted by the extrusion process. It notes that starch is a carbohydrate found in grains and potatoes that provides energy. Extrusion gelatinizes starch, improving digestibility, forming complexes with lipids, and increasing binding. Key factors in extrusion include heat, moisture, shear, and pressure. Extrusion decreases viscosity and impacts pasting characteristics. The type of starch, temperature, and pressure influence properties of the extruded product.
The document discusses the homogenization process. It begins by defining homogenization and emulsification as mechanical processes that reduce the size of fat globules in foods like milk. This increases stability by preventing creaming and improves texture. The document then describes the main types of homogenizers like pressure and ultrasonic homogenizers. It provides details on how pressure homogenizers work to reduce fat globule size under extreme pressure. The document concludes with discussing the effects of homogenization on viscosity, color, nutrition and shelf life of foods. It also provides an example of homogenization in ice cream manufacturing.
The document defines and describes extrusion processing. Extrusion is a process that converts raw materials into a desired shape and form by forcing it through a die under pressure while applying heat. It involves mixing, kneading, shearing, heating, cooling, shaping and forming. Many food products are made using extrusion, such as cereals, pastas, pet foods and meat products. Extrusion can be done using single-screw or twin-screw extruders in a cold or hot process. Examples of foods made by extrusion include baby food, textured vegetable protein, breakfast cereals and snacks.
Homogenization or homogenization is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout.When milk is properly homogenized, the cream will not rise to the top.Homogenization is regarded as a safe process that does not cause any problems in digesting milk. In fact, research is showing that homogenization may actually have some health benefits by making milk fat more digestible. Increased digestion of milk fat is huge.
This document describes a shortening activated cake emulsifier called Masemul EF 25. It discusses how traditional emulsifiers are limited in cakes but Masemul EF 25 overcomes these limitations. The formulation for Masemul EF 25 is provided, consisting of various emulsifiers, lecithin, oil and texturizer. Processing instructions for making Masemul EF 25 via a texturizing plant are also included. A yellow cake recipe and instructions are provided to test Masemul EF 25, finding it performs excellently by decreasing density, increasing heights, providing excellent moistness and maintaining quality over 6 months.
The limited availability of durum wheat and its relatively high price induce the search for alternatives that help to save costs while maintaining quality. The addition of vital wheat gluten is a viable but expensive method, and the application of hydrocolloids such as guar gum is limited to certain applications, e.g. instant noodle flour. The improving effect of specific emulsifiers and the recently discovered beneficial action of certain enzymes will be the subject of this article.
The document discusses the structure and composition of eggs. It describes the commercial evaluation of eggs based on weight, grade, and interior quality assessed by candling. Methods for research evaluation include measuring albumen height using a micrometer or caliper. During storage, egg quality decreases as the air cell increases in size, yolk enlarges, white thins, and odor/flavor deteriorates. Proper storage temperature and humidity can help maintain quality. Eggs function as coagulants, emulsifiers, and foaming agents in foods. Processed eggs are marketed in refrigerated, dried, and frozen forms to extend shelf life.
This document discusses how starch is impacted by the extrusion process. It notes that starch is a carbohydrate found in grains and potatoes that provides energy. Extrusion gelatinizes starch, improving digestibility, forming complexes with lipids, and increasing binding. Key factors in extrusion include heat, moisture, shear, and pressure. Extrusion decreases viscosity and impacts pasting characteristics. The type of starch, temperature, and pressure influence properties of the extruded product.
The document discusses the homogenization process. It begins by defining homogenization and emulsification as mechanical processes that reduce the size of fat globules in foods like milk. This increases stability by preventing creaming and improves texture. The document then describes the main types of homogenizers like pressure and ultrasonic homogenizers. It provides details on how pressure homogenizers work to reduce fat globule size under extreme pressure. The document concludes with discussing the effects of homogenization on viscosity, color, nutrition and shelf life of foods. It also provides an example of homogenization in ice cream manufacturing.
The document defines and describes extrusion processing. Extrusion is a process that converts raw materials into a desired shape and form by forcing it through a die under pressure while applying heat. It involves mixing, kneading, shearing, heating, cooling, shaping and forming. Many food products are made using extrusion, such as cereals, pastas, pet foods and meat products. Extrusion can be done using single-screw or twin-screw extruders in a cold or hot process. Examples of foods made by extrusion include baby food, textured vegetable protein, breakfast cereals and snacks.
Homogenization or homogenization is any of several processes used to make a mixture of two mutually non-soluble liquids the same throughout.When milk is properly homogenized, the cream will not rise to the top.Homogenization is regarded as a safe process that does not cause any problems in digesting milk. In fact, research is showing that homogenization may actually have some health benefits by making milk fat more digestible. Increased digestion of milk fat is huge.
This document describes a shortening activated cake emulsifier called Masemul EF 25. It discusses how traditional emulsifiers are limited in cakes but Masemul EF 25 overcomes these limitations. The formulation for Masemul EF 25 is provided, consisting of various emulsifiers, lecithin, oil and texturizer. Processing instructions for making Masemul EF 25 via a texturizing plant are also included. A yellow cake recipe and instructions are provided to test Masemul EF 25, finding it performs excellently by decreasing density, increasing heights, providing excellent moistness and maintaining quality over 6 months.
Effect of high pressure processing on protein and starchMaya Sharma
High Pressure Processing (HPP) is a non-thermal pasteurization technique that subjects food sealed in packaging to pressures of 40-1000 MPa. It provides several benefits over conventional thermal processing like retaining color, flavor, and nutrients. HPP causes less structural changes to proteins and starch in food compared to heat. For proteins, it can cause denaturation but retains functionality. Studies show HPP processing eggs, meats, dairy products and tofu results in improved texture and safety while maintaining nutrition. It also enhances starch gelatinization and cheese ripening. In summary, HPP is an effective non-thermal food processing method that improves safety and shelf life while better preserving the quality of proteins and starch in foods.
Extrusion technology provides a number of major benefits over the more traditional pellet milling processes commonly used for aquaculture feeds. In particular, extrusion can provide a much higher degree of control over the “cook” achieved, as well as better control of the product density (therefore controlling the floating/sinking characteristics).
Eggs primarily contain protein and are a cheap, nutritious food in the UK. The main proteins in eggs are ovalbumin, conalbumin, and ovomucoid. An egg has an outer shell, inner egg white divided into thick and thin layers, and a nutrient-rich egg yolk. Eggs are processed into frozen whole eggs or dried eggs through pasteurization and spray or freeze drying. Heat causes egg proteins to coagulate, forming gels or thickening mixtures. Eggs are used in many recipes to bind, emulsify, aerate, and add flavor.
Application of ultrafiltration technique for the quality improvement of dahi ...Ganga Sahay Meena
This document describes a study on using ultrafiltration techniques to improve the quality of dahi, a fermented milk product from India. Ultrafiltered buffalo milk with varying protein levels was used to produce dahi. Dahi made from ultrafiltered milk showed increased firmness, stickiness, sensory scores and decreased whey separation compared to the control dahi made without ultrafiltration. Principal component analysis revealed that protein content was positively correlated with attributes like firmness while negatively correlated with whey separation. Overall, ultrafiltration improved the quality attributes of dahi by increasing the protein levels in milk.
To study the performance of Palm Kernel Oil in the use of non dairy whip toppingIJERA Editor
Palm Kernel Oil is most suitable for Non dairy whip topping.The results show that The cream which is produced from PKO is smooth,Glossy and Shine,which has more shelf life than dairy whip topping.This study also shows that, the foam which is produced is more stable in whipping cream.this study also point out advantags of palm kernel oil based whipping cream,particularly when stability of cream is more important.
This document discusses milk powder production and properties. It begins by describing the historical drying of milk by exposing it to sun and how modern plants now produce milk powder on a large scale. It then discusses the different types of milk powder, including skim milk powder and whole milk powder. It provides details on the production processes, standards, shelf lives, and uses of various milk powders.
ABSTRACT- The present study was undertaken to make paneer enriched with fiber otherwise fiber deficient paneer. Coconut powder is in the form of fiber was included in the preparation of paneer. Paneer is one such product which is a regular dietary favorite among the Indians. Paneer has short life span at room temperature. So, the present study was aimed to assess the shelf life of salted paneer at different intervals in refrigeration temperature and physico-chemical attributes also. Paneer is prepared by combined action of acid coagulants and heat treatment of buffalo and cow milk or a combination thereof. Paneer have pleasant odour and characteristic mild acidic flavour. No extraneous coloring matter should be added to paneer at any stage. Paneer is a highly perishable product and has limited shelf life, largely because of its high moisture content. Its shelf life was reported to be only six days under refrigeration, though its freshness is lost within three days. The spoilage of paneer occurs mainly due to the growth of microorganisms, which bring about various physico-chemical changes. The growth of microorganisms can be delayed and shelf life of paneer be increased by addition of salt in the paneer. All treatment combinations were analyzed for a total viable count (bacteria) on nutrient agar and fungi on PDA and Coliform on Mcconkey agar. All the samples had bacteriological count ranging from 1x104 to 14x104 cfu/gm. And in all samples coliform was absent, so the product was found to be good and proper hygienic condition were maintain during the preparation, handling, and storage.
Key words: Paneer, Standard Plate Count, Chemical analysis, Yeast and mould count, Fiber
This document discusses factors that affect pellet quality and production rate in feed pelleting. It addresses how formulation, grinding, conditioning, die size, and cooling impact pellet formation. Precise moisture control in mixing is shown to improve pellet quality. Future developments discussed include conditioner modifications, expanders, compactors, and pressure pelleting to better control starch gelatinization for improved pellet strength and throughput.
This document provides an overview of corn silage inoculants. It discusses the fermentation process in silage, types of chemical additives like organic acids and ammonia, and different types of inoculants. Regarding inoculants, it describes their roles in fermentation and effectiveness in improving silage quality and animal performance. Key findings are that traditional homofermentative inoculants enhance fermentation, while newer heterofermentative inoculants containing Lactobacillus buchneri improve aerobic stability but may result in greater nutrient losses. Proper application and storage of inoculants is important for their effectiveness.
Bread is the product of baking a mixture of flour, water, salt, yeast and other ingredients. The basic process involves mixing of ingredients until the flour is converted into a stiff paste or.
How bread is made step by step?
How is bread produced?
What is the process of making bread?
Where is bread produced?
bread manufacturing process flow diagram
bread manufacturing process
bread making process in factory
how bread is made in a bakery
how is bread made in factories
how is bread processed
production of bread by fermentation
process of making bread from wheat
Technological Challenges of High Milk Protein FormulationsJuan Gonzalez
The formulation and processing of high protein nutritional dairy products present several challenges. Two product formats are discussed: powder products to be consumed as reconstituted beverages - the challenges are related to the consumer experience; and ready-to-drink (RTD) liquid products - the challenges are related to processing and stability.
Impact of non-processing technology in dairy products for microbial safety | ...FoodresearchLab
Dairy products, especially milk is highly perishable as it contains ample nutrition and high in moisture content for the microorganism to grow and multiply.
1.Pulsed electric Field (PEF)
2.High Pressure Processing (HPP)
3.Ultrasound (US)
4.Plasma and low plasma Technology (PT)
To Read More : https://bit.ly/2UX13af
This document summarizes an experiment on fermenting two types of milk (chocolate and 2% white milk) into yogurt. Key findings include:
- The chocolate milk fermented faster, as shown by its higher viscosity and lower pH over time compared to the 2% white milk. This is because the chocolate milk had a higher starting sugar content to fuel bacterial growth.
- Measurements of pH, alkalinity, temperature, and viscosity over time confirmed lactic acid production during fermentation in both milk samples.
- A mathematical model was developed to simulate bacterial growth, substrate utilization, and product formation kinetics during the fermentation process. The model matched the experimental results and showed faster fermentation in the
This document provides information about milk processing operations. It begins with an introduction to milk and its composition. The main constituents of milk are water, milk fat, milk proteins, milk sugar (lactose), enzymes, vitamins, and minerals. It then describes common milk processing operations like pasteurization, homogenization, and cream separation. Pasteurization involves heating milk to high temperatures to eliminate harmful bacteria. Homogenization breaks down milk fat globules for a creamier texture. Cream separation separates milk into cream and skim milk using gravity or centrifugal force. The document also discusses standardization, mixing ingredients, and properties of milk.
This document discusses milk processing operations such as pasteurization, homogenization, and cream separation. It provides details on:
- Pasteurization methods including low temperature long time (LTLT), high temperature short time (HTST), and ultra high temperature (UHT) processing.
- Homogenization which breaks down milk fat globules to reduce creaminess and improve digestion.
- Cream separation techniques using gravity or centrifugal force to separate higher density cream from lower density skim milk.
- Other operations like standardization, mixing of ingredients, and packaging are also briefly covered. The document provides an overview of key milk processing steps and techniques.
Food processing, composition of milk, microorganism present, Different type of adulteration test (sugar, starch, Salt, urea), biochemical test (organoleptic, clot on boiling, alcohol, lactometer, fat determination, protein determination), different type of pasteurization, processing, spray drying, Standards of PFA, FSSAI, BIS (profile and regulations) & non food application of milk.
Milk undergoes several processes to produce dairy products for consumers. Pasteurization and homogenization increase milk's shelf life and improve its appearance. During cheese production, starter cultures sour the milk and rennet coagulates it into curd. The curd is then processed depending on the type of cheese. Yogurt is made through bacterial fermentation of milk into a curdled product. Butter is produced by churning cream to form solid grains. Ice cream contains dairy or vegetable fats, sugars, and air cells incorporated during freezing.
The document discusses common questions and issues that arise in bakery production. It addresses why salt is used in breadmaking, why dough is knocked back, why a wet cloth is used during fermentation, and factors that influence cake volume and avoid sinking. It also explains why fruit may sink in fruitcakes, what occurs to cake batters in the oven, why an acidic medium is added to puff pastry dough, and factors that affect choux pastry volume and meringue stability.
Effect of high pressure processing on protein and starchMaya Sharma
High Pressure Processing (HPP) is a non-thermal pasteurization technique that subjects food sealed in packaging to pressures of 40-1000 MPa. It provides several benefits over conventional thermal processing like retaining color, flavor, and nutrients. HPP causes less structural changes to proteins and starch in food compared to heat. For proteins, it can cause denaturation but retains functionality. Studies show HPP processing eggs, meats, dairy products and tofu results in improved texture and safety while maintaining nutrition. It also enhances starch gelatinization and cheese ripening. In summary, HPP is an effective non-thermal food processing method that improves safety and shelf life while better preserving the quality of proteins and starch in foods.
Extrusion technology provides a number of major benefits over the more traditional pellet milling processes commonly used for aquaculture feeds. In particular, extrusion can provide a much higher degree of control over the “cook” achieved, as well as better control of the product density (therefore controlling the floating/sinking characteristics).
Eggs primarily contain protein and are a cheap, nutritious food in the UK. The main proteins in eggs are ovalbumin, conalbumin, and ovomucoid. An egg has an outer shell, inner egg white divided into thick and thin layers, and a nutrient-rich egg yolk. Eggs are processed into frozen whole eggs or dried eggs through pasteurization and spray or freeze drying. Heat causes egg proteins to coagulate, forming gels or thickening mixtures. Eggs are used in many recipes to bind, emulsify, aerate, and add flavor.
Application of ultrafiltration technique for the quality improvement of dahi ...Ganga Sahay Meena
This document describes a study on using ultrafiltration techniques to improve the quality of dahi, a fermented milk product from India. Ultrafiltered buffalo milk with varying protein levels was used to produce dahi. Dahi made from ultrafiltered milk showed increased firmness, stickiness, sensory scores and decreased whey separation compared to the control dahi made without ultrafiltration. Principal component analysis revealed that protein content was positively correlated with attributes like firmness while negatively correlated with whey separation. Overall, ultrafiltration improved the quality attributes of dahi by increasing the protein levels in milk.
To study the performance of Palm Kernel Oil in the use of non dairy whip toppingIJERA Editor
Palm Kernel Oil is most suitable for Non dairy whip topping.The results show that The cream which is produced from PKO is smooth,Glossy and Shine,which has more shelf life than dairy whip topping.This study also shows that, the foam which is produced is more stable in whipping cream.this study also point out advantags of palm kernel oil based whipping cream,particularly when stability of cream is more important.
This document discusses milk powder production and properties. It begins by describing the historical drying of milk by exposing it to sun and how modern plants now produce milk powder on a large scale. It then discusses the different types of milk powder, including skim milk powder and whole milk powder. It provides details on the production processes, standards, shelf lives, and uses of various milk powders.
ABSTRACT- The present study was undertaken to make paneer enriched with fiber otherwise fiber deficient paneer. Coconut powder is in the form of fiber was included in the preparation of paneer. Paneer is one such product which is a regular dietary favorite among the Indians. Paneer has short life span at room temperature. So, the present study was aimed to assess the shelf life of salted paneer at different intervals in refrigeration temperature and physico-chemical attributes also. Paneer is prepared by combined action of acid coagulants and heat treatment of buffalo and cow milk or a combination thereof. Paneer have pleasant odour and characteristic mild acidic flavour. No extraneous coloring matter should be added to paneer at any stage. Paneer is a highly perishable product and has limited shelf life, largely because of its high moisture content. Its shelf life was reported to be only six days under refrigeration, though its freshness is lost within three days. The spoilage of paneer occurs mainly due to the growth of microorganisms, which bring about various physico-chemical changes. The growth of microorganisms can be delayed and shelf life of paneer be increased by addition of salt in the paneer. All treatment combinations were analyzed for a total viable count (bacteria) on nutrient agar and fungi on PDA and Coliform on Mcconkey agar. All the samples had bacteriological count ranging from 1x104 to 14x104 cfu/gm. And in all samples coliform was absent, so the product was found to be good and proper hygienic condition were maintain during the preparation, handling, and storage.
Key words: Paneer, Standard Plate Count, Chemical analysis, Yeast and mould count, Fiber
This document discusses factors that affect pellet quality and production rate in feed pelleting. It addresses how formulation, grinding, conditioning, die size, and cooling impact pellet formation. Precise moisture control in mixing is shown to improve pellet quality. Future developments discussed include conditioner modifications, expanders, compactors, and pressure pelleting to better control starch gelatinization for improved pellet strength and throughput.
This document provides an overview of corn silage inoculants. It discusses the fermentation process in silage, types of chemical additives like organic acids and ammonia, and different types of inoculants. Regarding inoculants, it describes their roles in fermentation and effectiveness in improving silage quality and animal performance. Key findings are that traditional homofermentative inoculants enhance fermentation, while newer heterofermentative inoculants containing Lactobacillus buchneri improve aerobic stability but may result in greater nutrient losses. Proper application and storage of inoculants is important for their effectiveness.
Bread is the product of baking a mixture of flour, water, salt, yeast and other ingredients. The basic process involves mixing of ingredients until the flour is converted into a stiff paste or.
How bread is made step by step?
How is bread produced?
What is the process of making bread?
Where is bread produced?
bread manufacturing process flow diagram
bread manufacturing process
bread making process in factory
how bread is made in a bakery
how is bread made in factories
how is bread processed
production of bread by fermentation
process of making bread from wheat
Technological Challenges of High Milk Protein FormulationsJuan Gonzalez
The formulation and processing of high protein nutritional dairy products present several challenges. Two product formats are discussed: powder products to be consumed as reconstituted beverages - the challenges are related to the consumer experience; and ready-to-drink (RTD) liquid products - the challenges are related to processing and stability.
Impact of non-processing technology in dairy products for microbial safety | ...FoodresearchLab
Dairy products, especially milk is highly perishable as it contains ample nutrition and high in moisture content for the microorganism to grow and multiply.
1.Pulsed electric Field (PEF)
2.High Pressure Processing (HPP)
3.Ultrasound (US)
4.Plasma and low plasma Technology (PT)
To Read More : https://bit.ly/2UX13af
This document summarizes an experiment on fermenting two types of milk (chocolate and 2% white milk) into yogurt. Key findings include:
- The chocolate milk fermented faster, as shown by its higher viscosity and lower pH over time compared to the 2% white milk. This is because the chocolate milk had a higher starting sugar content to fuel bacterial growth.
- Measurements of pH, alkalinity, temperature, and viscosity over time confirmed lactic acid production during fermentation in both milk samples.
- A mathematical model was developed to simulate bacterial growth, substrate utilization, and product formation kinetics during the fermentation process. The model matched the experimental results and showed faster fermentation in the
This document provides information about milk processing operations. It begins with an introduction to milk and its composition. The main constituents of milk are water, milk fat, milk proteins, milk sugar (lactose), enzymes, vitamins, and minerals. It then describes common milk processing operations like pasteurization, homogenization, and cream separation. Pasteurization involves heating milk to high temperatures to eliminate harmful bacteria. Homogenization breaks down milk fat globules for a creamier texture. Cream separation separates milk into cream and skim milk using gravity or centrifugal force. The document also discusses standardization, mixing ingredients, and properties of milk.
This document discusses milk processing operations such as pasteurization, homogenization, and cream separation. It provides details on:
- Pasteurization methods including low temperature long time (LTLT), high temperature short time (HTST), and ultra high temperature (UHT) processing.
- Homogenization which breaks down milk fat globules to reduce creaminess and improve digestion.
- Cream separation techniques using gravity or centrifugal force to separate higher density cream from lower density skim milk.
- Other operations like standardization, mixing of ingredients, and packaging are also briefly covered. The document provides an overview of key milk processing steps and techniques.
Food processing, composition of milk, microorganism present, Different type of adulteration test (sugar, starch, Salt, urea), biochemical test (organoleptic, clot on boiling, alcohol, lactometer, fat determination, protein determination), different type of pasteurization, processing, spray drying, Standards of PFA, FSSAI, BIS (profile and regulations) & non food application of milk.
Milk undergoes several processes to produce dairy products for consumers. Pasteurization and homogenization increase milk's shelf life and improve its appearance. During cheese production, starter cultures sour the milk and rennet coagulates it into curd. The curd is then processed depending on the type of cheese. Yogurt is made through bacterial fermentation of milk into a curdled product. Butter is produced by churning cream to form solid grains. Ice cream contains dairy or vegetable fats, sugars, and air cells incorporated during freezing.
The document discusses common questions and issues that arise in bakery production. It addresses why salt is used in breadmaking, why dough is knocked back, why a wet cloth is used during fermentation, and factors that influence cake volume and avoid sinking. It also explains why fruit may sink in fruitcakes, what occurs to cake batters in the oven, why an acidic medium is added to puff pastry dough, and factors that affect choux pastry volume and meringue stability.
1. 21/08/2020 EGG WHITE EXAMINATION
file:///C:/Users/PRF/Desktop/área de trabalho/Desktop/Aulas 2014 II/Ovos/Aulas Práticas Gerais/EGG WHITE EXAMINATION.htm 1/4
THE CASE OF THE MISSING YOLK
PROBLEM:
Grandma calls one night. She was making your favorite lemon meringue pie when she realized the meringue
was not as fluffy as usual. Knowing your background as a food chemist, grandma wants to know if you can
figure out why her meringue is flat.
BACKGROUND INFORMATION:
Any foam (shaving cream, Dream Whip®, or Silly String®) can be identified as a two phase-colloidal
dispersion in which the gas phase (nitrogen or air) is dispersed and enrobed by a thin film of foaming
(surface active) agent, in a liquid phase. For a protein to be a successful foaming agent, it must be able to
stabilize the new surface area that is continuously created during the making of foam. Therefore, the physical
properties of proteins will play a major role in the production and performance of foam.
Egg white has been successful as the major foaming protein used in the food industry. The industry uses egg
white as a functional ingredient in food products that require foams in several products including cakes,
soufflés, meringues, candy and other suitable products that require air bubble incorporation. The success is
due to the capacity of egg whites to form uniform foams of good volume while ensuring foam stability in the
presence of other compounds and also upon heating. This reflects the unique combination of proteins with
different physical properties that occur in egg whites.
The egg white foams have large interfacial foam areas, and this makes them unstable. The foam can break
apart by 1) leakage of liquid phase due to pressure differences, 2) air coalescence from small to large bubbles
and 3) rupture of liquid phase separating air bubbles. Low interfacial tension, high viscosity of liquid phase
and strong elastic film of absorbed protein will stabilize the foams.
Several factors, in addition to the protein, affect the foaming properties of proteins. These include protein
concentration, pH, temperature, salt, sugars and lipids.
During drying of egg white, the minute quantities of lipids (approximately 0.1%) from contaminating egg
yolk, if present, can interfere with the conformation of adsorbed protein films by placing themselves at the
air/water interface thus reducing the foaming ability of egg white.
OBJECTIVE:
To become familiar with physical changes that occur in the production of foam and the mechanism of egg
white foam formation.
To become familiar with methods of foam measurements and investigate the effect of sugar, pH, and salt
on foam production and stability.
To demonstrate foam production in meringue.
MATERIALS:
Eggs (1 dozen per group)
Potassium tartrate (Cream of Tartar) saturated solution
Mixer
250 ml beakers
100 ml beakers
250 ml Erlenmeyer flasks
100 ml Graduated cylinders
SAFETY AND DISPOSAL:
There are no real safety issues or concerns regarding this lab, except do not put raw egg in your mouth.
There is a remote possibility of Salmonella contamination in raw eggs. Wash hands thoroughly after
finishing the lab.
2. 21/08/2020 EGG WHITE EXAMINATION
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TIME:
Approximately one hour.
PROCEDURES:
A. Separation of egg white from whole egg
1. The whole egg consists of shell, yolk, and egg white liquid. Separate the egg white carefully
since small amounts of yolk will contaminate the egg white. This can adversely affect the
whipping properties of egg white.
2. Collect 80 ml of egg white in a weighed 250 ml Erlenmeyer flask and note the weight of the egg
white.
B. Pretreatment of egg white
1. pH adjustment - The pH of the native egg white is around 9.0 due to the presence of basic amino
acids. Adjust the pH of egg white to about 7.0 with saturated potassium acid tartrate solution to
minimize the extent of denaturation of proteins under alkaline conditions during pasteurization.
Stir the egg white gently during the pH adjustment.
2. Pasteurization - Heat egg white at 60C for 3 ― minutes (Do not cook too long. Extensive
denaturation can result in a decrease in foam production). Cool to room temperature. The heated
egg white forms better foams with greater numbers of air bubbles and increased rigidity than
does unheated natural protein.
C. Foam Production
1. Whipping - When using an electric mixer, be sure to lock beaters in place before turning it on.
Turn mixer to first setting (low) and slowly work up to a setting of 10. Whip the egg white liquid
for 3 minutes in a kitchen mixer on a setting of 10.
D. Assessment of foaming properties:
1. Foam Density - Fill a 100-ml pre-weighed weighing boat with the foam produced and weigh to
get the foam weight. Calculate the foam density:
Foam Density = Weight of foam ũ Volume of foam
2. Foam Capacity - The foaming capacity can be determined by "overrun" and is defined as the
change in density of a given volume of a foam and is expressed as percent change in volume.
% Change in Volume = ( Wt. of 100 ml protein - Wt. of 100 ml of foam) x 100
% Change in Volume = ( Wt. of 100 ml of foam
EXTENSION:
Foam Stability Determination: Determine the weight of the remaining foam and place it on cheesecloth in a
large funnel at room temperature. Collect the liquid (drip) into a 100-ml pre-weighed beaker and note the
weight of the egg white drip plus beaker at 10-minute intervals for 60 minutes. Plot the weight of egg white
drip against time. Estimate the time taken for 50% of the foam to drip from this plot.
Stability Index = Time to attain 50% (w/w) drainage
Time 0 min. 10 min. 20 min. 30 min. 40 min. 50 min. 60 min.
Weight of drip
Plot the weight of egg white drip (Y axis) against time (X axis)
C. Sucrose Addition and Meringue Preparation
1) The egg white (80 g) is whipped at setting 10 for 2min, the speed is decreased to setting 6 and sucrose (45
grams) added in three increments at four second intervals. The whipping is continued at setting 10 for 6min.
The stability index of meringue is determined as described under foam stability determination. Sucrose is a
3. 21/08/2020 EGG WHITE EXAMINATION
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soluble polar compound, which increases bulk viscosity of egg white liquid, thereby improving foam
stability.
Time 0 min. 10 min. 20 min. 30 min. 40 min. 50 min. 60 min.
Weight of drip
Plot the weight of egg white drip (Y axis) against time (X axis)
QUESTIONS:
1. How do proteins lower the interfacial tension during whipping of egg white?
2. Why is mechanical energy required in foam production?
3. What is the function of surface-active agents in foam production?
4. How does viscosity stabilize foams?
5. Egg white foams for product application are produced outside the natural pH and pI at which
maximum foaming and stability occurs. Why?
FOR ADDITIONAL INFORMATION CONTACT:
Dr. Navam Hettiarachchy
REFERENCES:
Altschull, A.M. and H.L. Wilcke. 1985. New Food Proteins. Vol. 5. Academic press Inc., New
York, NY. p. 155-161.
Fennema, O.R. 1985, 2 nd ed. Food Chemistry. Marcel Dekker Inc., New York, NY.
Chapters 5 and 14. pps 246-369 and 829-855.
Halling, J.H. 1981. Protein-stabilized foams and emulsions. CRC Critical Review in Food Science
and Nutrition. pps 155-203.
Hettiarachchy, N.S. and G.R. Ziegler (Eds.) 1994. Protein Functionality in Food Systems. IFT
Basic Symposium Series, Marcel Dekker Inc., New York. Chapter 6, p. 181-208.
Johnson, J.M. and M.E. Zabik. 1981. Egg Albumin Protein Interactions in an Angel Food Cake
System. J. Food Sci. 46:1231-1222, 1236.
Poole, S., S. West and C.L. Walters. 1984. Protein-protein Interactions: Their Importance in the
Foaming of Heterogeneous Protein Systems. J. Sci. Food Agric. 35: 701-711.
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