Food Science Unit 5 - Food Processing

Introduction

The action of performing a series of mechanical or chemical operations on food in order to change or preserve it.
Food processing takes clean, harvested or slaughtered and butchered components and uses them to produce marketable food products.
Unless natural foods are processed and preserved, they will deteriorate.

Objectives of Food Processing

The main objectives of food processing are:
1.Removal of unwanted matter from the food.
Unwanted matter may be inedible, indigestible or harmful to health. Unwanted matter is removed by appropriately designed gadgets. The processes may include shelling, destoning, milling, peeling etc.

2.Making food safe for consumption.
Some foods contain natural toxins which need to be inactivated. Fungal growth on food items, infected portion of food are removed by visual examination. Heat is used to destroy microorganisms and their toxins.

3. Increasing Digestibility 
Most foods are difficult to digest unless they are cooked. Cooking softens fiber, gelatinizes starch, denatures protein and makes food easier to digest. With exceptions to fruits and some vegetables, all other foods need some kind of processing to make them more digestible.

4. Enhance flavor, colour and taste 
The acceptability of food depends to a large extent on its sensory qualities. Processing techniques enhance the appearance of food and many techniques make food more appetizing and tasteful.

5. Improving texture and consistency 
Processes such as emulsification, aeration, gel formation are aimed at improving the texture and consistency of ready-to-eat, cook-chill and cook-freeze operations.

6. Minimizing nutrient loss 
Nutrients are better retained by controlled processing conditions. Nutrients lost during processing are generally compensated by adding synthetic vitamins.

7. Extending the shelf life 
Processing extends the shelf life because apart from removing unwanted, spoilt and harmful matter and subjecting the food to temperatures outside the danger zone, all processes such as dehydration, cold storage, canning and pasteurization are aimed at preservation of food.

8. Increasing acceptability through fabricated foods 
New products of uniform size and shape are being introduced in the market. They are made from low grade commodities which are plentiful or good for health.

So to summarize,

• Foods are processed for the following reasons:
• All the raw food materials are processed to improve their palatability, nutritional value and shelf-life.
• Preservation for later consumption or sale to fetch better price
• Removal of inedible portions
• Destruction or removal of harmful substances 
• To boost the shelf life of food articles.
• To prevent contamination of food.
• For transportation and food storage.
• To turn food products into the ones that appeal to customers.

Food Spoilage and Contamination

Food can spoil at any stage in its preparation or storage. In fact, spoilage in food begins as soon as

Vegetables and fruits are harvested.
Eggs are laid.
Fish is caught
Animals are slaughtered for meat.
Milk is drawn from milch animals.
This spoilage continues till food is consumed.

Food Contamination: 
The term contaminated is used for those foods which are not fit to be eaten for sanitary reasons. Although contaminated food may look, smell and taste good, it may contain harmful chemicals, non-food matter and bacteria. Contamination of food results in its spoilage.

Food Spoilage:
It is the decomposition or damage causing undesirable changes in food. It is caused due to various agents making food unsuitable for consumption. Spoiled food looks, smells and tastes bad.

Causes of Food Spoilage

Food spoils because of any one or more of the following reasons.

• Growth and activity of bacteria, yeast and mold – Micro-organisms can cause visible changes in the food.
• Insect infestation – Insects such as worms, weevils and moths infest cereal grains and make grains unfit for consumption.
• Enzymatic changes – Natural enzymatic changes also cause food spoilage.
• Chemical action – Rancidity.
• Physical Changes.

Methods of Food Preservation

Use of Low Temperatures

Low temperatures preserve food by retarding chemical reactions, enzymatic action, growth and activity of microorganisms. The lower the temperature , the better the food will be preserved. Microorganisms are not killed at low temperatures.

The various food preservation techniques using low temperature are as follows:

1. Refrigeration / Chilling
2. Cook – Chill
3. Freezing
4. Cook – Freeze
5. Vacuum Packing

Refrigeration / Chilling

Temperature of 1 to 40C prevents food from spoiling for short periods.
Frozen foods kept at -180C preserves food for a year.
Frozen food kept at -280C preserves food for a two years.
Chilling temperatures retard microbial growth and biochemical changes which affect colour, texture, flavor and nutritive value.
Food can be kept at chilling temperatures for a limited period and have to consumed by the ‘best before date’.
Relative humidity needs to be controlled when fruits and vegetables are stored in refrigerators. Low RH means loss of moisture and shrinkage in them and high RH favours surface spoilage by microorganisms.

Cool - Chill
In this system, food is cooked in the kitchen in advance and rapidly chilled and stored at 0 – 30C.
It is reheated just before it is served.
The cook – chill system is used for almost all kinds of foods and is popular in airlines and institutional catering.
Proper cooking procedures and hygienic standards need to be followed to ensure safety and quality.

Precautions for Cook – Chill Foods
Food should be properly cooked to destroy the microorganisms and the cooking process should be complete.
Cooked food should be portioned and chilled in a blast chiller unit within 30 minutes of cooking.
Chilling temperature of 30C must be reached within 11/2 hours after cooking.
Chilled storage temperature should be between 00C to 30C
While distributing cook-chill foods, temperature should be as low as possible.
During reheating the temperature must reach 700C.
Food should be reheated just before it is consumed and must be consumed after 2 hours of reheating.
If the temperature exceeds 100C during storage or distribution the food must be discarded.
Recipes should be suitably modified.
The storage life of cook-chill meals should not exceed 5 days.

Freezing

Food is preserved for long periods by reducing the temperature to -180C or lower.

At this temperature, water gets converted into ice and microbial growth stops.
Freezing retains colour, flavor and nutritive value.
If properly stored, frozen food has a self life of 3 – 12 months.
Food is quickly frozen by using any one of the following equipments.


Blast Freezers – In this cold air at -180C to -340C is vigorously circulated over food while it passes through an insulated tunnel.

Plate Freezers – Food to be frozen is placed in contact with a metal surface which is cooled by a refrigerant. It is used for ice creams, juices, etc., both packaged and unpackaged foods.

Immersion freezers – packaged or unpackaged food is frozen by immersing it or spraying it with a freezing agent. It is used for freezing poultry.

Spray freezers – This is the quickest freezing method in which liquid nitrogen or carbon dioxide is used. It is called cryogenic freezing. The food to be frozen is placed on  conveyor belt which passes through an insulated freezing tunnel. Liquid nitrogen or carbon dioxide is injected into the tunnel through a spray which changes its state and vaporizes, resulting in instant freezing.

Freeze flow – In this system, food freezes but does not harden. A wide variety of frozen foods, both cooked and uncooked are available in the market. A cryoprotectant  is used. Frozen foods once thawed should not be refrozen as when it is thawed its temperature is in the danger zone where bacteria present in the food multiply rapidly.

Cook – Freeze – It is a specialized method of a food processing system in which food is cooked  and immediately blast frozen at -18oC or below and stored at this temperature till it has to be served. It has a shelf life of 3 – 6 months.

Vacuum Cooking

Vacuum cooking is a form of cook – chill using a combination of processes. The food is first sealed in a plastic pouch. It is then cooked by steam and quickly chilled in ice water. 

Although this system has many advantages, its main disadvantages are uneven cooking if size of cut food varies, longer cooking time, and extra cost of vacuum pouches and packing equipments.
Vacuum packed food does not get oxidized and once packed.
Packs must be stored at appropriate storage temperature, well labelled and FIFO must be followed strictly.

Flow of Freezing Process for Fruit Based Products

Flow of Freezing Process for Veg. Based Products

Use of High Temperatures

High temperatures destroy microorganisms by denaturation of cell proteins and inactivation of enzymes needed by them for their metabolism. At temperatures above 630C, bacteria stop multiplying and as the temperature increases, they are gradually destroyed.

The Thermal Death Time (TDT) is the time needed at a given temperature to kill a number of microbes. The heat used to destroy microbes maybe in the form of wet heat or dry heat.

Uses of High Temperatures
WET HEAT

This is more commonly used in the food industry. If carefully administered, it is a useful method of controlling microorganisms. The food processing techniques using wet heat are as follows:

1.Blanching: Foods which are to be frozen, dried or canned are immersed in hot boiling water for a few minutes prior to processing. Balancing helps in removal of peel, inactivation of enzymes that oxidize vitamin C, removal of gas from tissue spaces and wilting of tissues. The enzymes which bring about discoloration or browning seen in apples, pears and potatoes are also inactivated.

2. Pasteurization – This method is used to control microorganisms in milk, fruit juices and wines. Food may be pasteurized by any one of the three methods:
Low temperature holding (LTH) method at 620C for 30 minutes
High temperature short time (HTST) or flash method at 720C for 15 seconds.
Ultra high temperature sterilization (UHTS) at temperatures above 1350C for 2 seconds. This method makes food commercially sterile. Such foods are packed under aseptic conditions and can be stored at room temperature for three to six months.

3. Canning -  In this process, temperatures used are above 1000C. All microorganisms that could spoil food under normal conditions of storage are destroyed by heating the food in an autoclave at temperatures between 1150C and 1250C.

• The exact temperature and time required for canning depends on the type of food to be canned.
• Acidic foods such as fruits are heated to 1000C only because acid also helps in preventing microbial growth.
• A vacuum is created inside the can or the air in the headspace may be replaced by nitrogen gas to prevent growth of aerobic bacteria.
• This is the most common method of food processing . It is used to preserve fruits, vegetables, fish, meat, poultry etc.
• In this process no preservatives are added to the food which is sealed in air tight containers. These are then heated to sterilize the food.

Canning Process

The following basic steps need to be followed while canning or bottling food:

1. Cleaning and Preparing – The food to be canned is cleaned thoroughly and prepared for canning.
2. Filling – Raw prepared food is filled into cans or bottles either mechanically or by hand. Filling should be carefully controlled to ensure that the headspace is neither too little nor too large.
3. Exhausting – A partial vacuum is created in the can by removing part of the air. As oxygen is reduced, bacterial spoilage is retarded. Exhausting prevents the ends of the can from bulging during heating.
4. Sealing – Cans and bottles are sealed with airtight lids by sealing machines.
5. Processing - The sealed containers are heated at a controlled temperature for a specified length of time. The time and temperature depends on the food being processed and the size of the container.
6. Cooling – As soon as processing is over, cans are cooled immediately to stop further cooking. Cans are cooled by dipping them in cold water  or even air cooling. He cans are then labelled and packed in cartoons to be marketed.

Advantages of Wet Heating

1. Convenience
2. Long Shelf life
3. Needs little preparation
4. No chemical preservatives
5. Variety of food is available.

Disadvantages of Wet Heating

1. Heat labile nutrients are lost.
2. Heat required for processing affects the texture, colour and flavor of the product.
3. Cost of canned food is high in India.
4. Once opened, canned food should be treated like fresh food and consumed within stipulated period.

Cooking (boiling, steaming, stewing and poaching)

In these methods of cooking, wet or moist heat is used. The temperature attained is 1000C.
At this temperature, most microorganism are destroyed but spores survive. Foods cooked by these methods cannot be stored for long periods under normal conditions.

Methods of Food preservation

DRY HEAT is used in the following methods.
Sun drying, Smoking and Freeze drying – In these methods, dry heat is used to control microorganisms. Dry heat brings about dehydration of the foods or the surface of the food. It destroys molds, yeast and most bacteria and spores.
Cooking (baking, roasting, grilling) – In these methods of cooking, food is cooked by dry heat. The temperature reached on the surface is approx. 1150C. Most bacteria are destroyed. Internal temperature of food is generally lower.
If food is to be kept for sometime, it should be cooked
thoroughly. Foods cooked by dry heat methods do not spoil as fast
as moist heat methods as they have a lower moisture content.

Removal of moisture from food
Microorganisms need moisture for their growth. If foods are dried or dehydrated (removal of moisture), they will not be spoilt by bacteria, yeast or molds.
Moisture can be removed by sun drying, mechanical dryers and freeze drying.

Sun Drying
It is used for certain fruits and vegetables. The dried items should be turned during drying. Light coloured fruits are sulphured to prevent enzymatic browning. It can be used in hot dry climates only.

Use of mechanical dryers
The food to be dried is passed on conveyor belts through hot air with controlled relative humidity, or hot air is passed through the food. Liquid food such as milk is dried by passing it over heated rollers. Dried food should b packed in airtight containers immediately.

Freeze Drying
In this process, the food to be dried is first frozen in a cabinet. A vacuum is created and by the process of sublimation the ice turns into vapours.
Freeze dried food needs no further refrigeration or preservation. It is light in weight and retains its size and shape , and when soaked in water regains its original size and flavor, It is used to dry fruits, vegetables, meat, poultry and seafood.

Advantages of Drying
Dried food is easy to transport and store.
It has a long shelf life provided it remains dry.
It occupies less storage space.
It is a cheap method of preservation and easy to use.

Effect of Heat, acid and Alkali on Food Constituents

Heat

High temperatures destroy harmful micro-organisms due to coagulation of cellular proteins and inactivation of enzymes required
For the metabolism of these organisms. Heat also causes dehydration which makes water unavailable for microorganisms to survive in.

Acids (Acetic Acid, Citric Acid)
Acids reduce the ph. level of foods below the growth range and also Inhibit metabolic activity.
Effect of Heat, acid and Alkali on Food Constituents

Alkali
 It causes high osmotic pressure causing plasmolysis (breakdown of cell walls) of cells. It dehydrates food by drawing out water and dehydrates microbial Cells.
It ionizes to yield chlorine which is harmful to microorganisms. It reduces solubility of oxygen in the moisture .
It interferes with the activity of proteolysis enzymes

Communication Unit 3 - Effective Speaking

What is Effective Speaking?

Effective speaking is simply the art of good conversation carried a step or two beyond the usual.
It is largely through the spoken word that we communicate with each other, develop understanding, exchange knowledge and find mutually acceptable goals.
Through effective speaking we can encourage, teach, entertain and inspire others.

Restaurant and Hotel English

In the hospitality industry, as an hotelier or restaurateur, every day you have to meet with many guests.

 According to different time and situation, you have to greet and introduce the guests.
You are suppose to use some essential expressions and styles to greet a guest, respond to any expression or give farewell to guest with courtesy etc.

Greeting Guest 

To ensure guest repetition and to make long lasting relationship it is very much indispensable to make good first impression to guests as it is said that first impression is that last impression.
All guests are need to be greeted affably after their arrivals at the hotel by an hotelier.

Essential Expressions

There are some magic expressions to greet guests and response to any greetings.
 Generally people use these words according to the level or gravity of relationship with the person he or she greets and timing of the greeting.
You should remember that there are some expressions which you should not use in formal situations like greeting a guest.

Essential Expressions (For Thanking)

Thank you very much Mr…. 

 I am very grateful for ….
 I really appreciate …
Thanks
Thanks a Million/ Lot

Essential Expressions (For Apology)

Sorry Sir
I am very sorry Ma’am/ Sir for …
Terribly sorry ….
Pardon me
Excuse Me
I apologize for …

Essential Expressions (Polite Replies)

You’re welcome
It’s my pleasure
It’s not a problem at all
Never mind
It’s okay
Not at all
I understand/ I completely understand
No problem
Don’t worry about that I’ll take care/ handle it
Let it be

Essential Expressions (Polite Inquires)

Would you like to have a cup of tea, sir?
Could you possibly spell your last name
May I have your passport, please?
Could you talk to our sales department?
Allow me to call a taxi/ cab for you.

Guest Complain Handling Guidelines

Here is a step by step guest complaint handling guideline for hotel or restaurant staffs.

Step 1: 

When a guest with a complaint or request approaches you, follow the basic steps of Making it Right.

Listen: 

Listen intently making mental notes, with the right body language (put on a serious face, nod your head). Take notes if information is very detailed and specific.

Apologise with Empathy: 

Apologise and put yourself in the guests, situation. No matter how insignificant the matter is to you, it must be dealt with seriously.

Find a Solution: 

All problems have a solution – that’s the approach to use. Try and find the simplest and clearest solution. If you are unable to, inform a supervisor or manager.

Follow Through: 

After the problem has been resolved, go back to the guest to ensure he is satisfied. Even if the problem is being solve by someone else, you were the one who the problem was brought to – follow through accordingly. Take personal responsibility of the issue.

Step 2:

The guest, who is complaining, should be informed of the action(s) being taken every step of the way. If you are unaware of what to do, inform the guest that you will inform a Supervisor /Manager and follow up with him/her within the next 10 minutes. Just tell the guest:

“Mr/Mrs/Miss “XYZ” I will inform the situation to my Supervisor/Manager n I shall revert back to you within the next 10 minutes.”

Step3:

Inform the Supervisor/Manger of the situation – make sure to give him / her all the information, including a background of the guest.

Step 4:

Supervisor/Manger must contact the guest and explain to him/he that he/she has been informed about the situation. The Supervisor/Manger must apologise for the situation and offer him/her an alternative  with something that the guest feels “outweighs” the problem.
If the guest is still not satisfied, the Department Head must be informed.

Step 5: 

After a solution has been reached, the key person who dealt with the guest on this case should go back and check to see if the guest is satisfied.

Step 6:

A log must be maintained detailing the situation.
Guest Complain Handling Guidelines

Step 7: 

The entire making it Right procedure should be completed within 24 hours.

Addressing a Group

Following are some steps of maintaining audience’s interest while addressing a group: 

1.Giving an indication of what will come later in your talk proves fruitful e.g.
In a few moments I will show you a video on ….

2.Using Illustrations:
Using examples, anecdotes or verbal illustrations to interest and suit your audience that comes from within the experience of the audience can break the ice and create empathy rather than sharing complicated anecdotes.

3. Asking questions and inviting participation:
Asking some general and easy question which can be aimed at the audience to invite them to participate and draw them into the natural thinking process develops a rapport between the speaker and the audience.

4. Talking directly to the audience:
Reaching out to the audience by walking out towards them with their name and making them feel like individuals and not just a part of the mass means half the battle is won.

5. Eye Contact:
Making an eye contact with the audience establishes a bond. Eye contact involves glancing at the faces of the audience for a few seconds and not staring continuously. A speaker can check his progress by gauging the audience reaction by looking at their faces which can indicate interested, puzzled, bored, pleasure etc.

6. Speaking Well: It depends upon factors like pace, pitch, tone, volume and pausing at the right places and articulation.
a) Pace- Addressing a group of audience requires a slight slower pace than informal conversation which can be brought through emphazing the main points which speaking.
Addressing a Group
b) Tone- It is the quality which expresses feelings. It can reveal emotions like warmth and sincerity and how strongly the speaker feels about a topic. A harshly critical or judgmental tone should be avoided as it makes the speaker’s sound harsh, aggressive and biased.
Addressing a Group
c) Volume- High volume doesn’t mean shouting. It means being audible to the people sitting in the back rows. Volume can be varied to make the seminar more lively and interesting.
d) Pausing- Pause doesn’t imply failure in fluency. It can be used to create great effect. It can focus attention on what has been said or about to be said or can be used to prepare the audience for a change in ideas.
Keeping in mind, the above points can be beneficial in addressing a group and bringing clarity in the speech.

Essential Qualities of a Good Speaker

Good Organisation

Prepare your notes in advance.
Notes preparation should be done keeping in mind the time allocated.
Make a note of all the peripherals you will require for your presentation.

Preparation

Speak from clear, comprehensive lecture notes.

Practice your presentation or voice, language and timing.
Do not read your presentation.

Confidence

Do not begin with an apology for your knowledge or your English. If you lack confidence in yourself, the audience will perceive it and lose confidence in you, too.
Be thoroughly prepared and familiar with your material; preparation creates confidence.
Pause occasionally. Never be afraid to stop speaking for a moment.
Speak at normal, slow rate. Do not rush.

Responsiveness

Start your presentation with a smile. You will put your audience at ease.
Make eye contact with members of the audience.
Do not talk to the back wall, the table, or your notes.
Find a few friendly, encouraging faces in the different parts of the audience and talk to them.
Check to see if the audience is following you.
Make sure you talk with, not at, your audience. Talking at an audience comes across as talking down to them.

Clarity

Be sure the organization of your talk is clear to the audience.
Make short, simple, specific statements.
Strive for a smooth transition from one point to the next.
Use visual support to illustrate and clarify difficult points.
Visuals should complement the oral presentation.
Visuals should be simple and should not require complex explanations.

Enthusiasm

When something is important say it slower and louder.

Try to communicate to the audience your own interest in and enthusiasm for your subject; enthusiasm is contagious.

Others

• Stand straight distributing your weight on both the legs. 
• Do not hold onto the mike or to the podium for support. 
• Have a good posture and appearance. Do not lean on the podium. 
• Be confident, relaxed and energetic. Do not play with your clothes or fingers. 
• Wear clothes that befit the occasion. 
• Close the speech with a striking, impressive, concluding remark. 

Purpose of a Speech.

The purpose of any speech can be categorized into broad headings: 

• General 
• Specific

There are three general speech purposes:

• To Inform: The main concern of the speaker here is to make the audience understand and remember the information presented. 
• To Persuade: The major objective of a persuasive speech to induce the audience to think, feel and act in a manner intended by the speaker. 
• To Entertain: Through such speeches, the speaker wants the audience to have an enjoyable time.

Specific purpose describes the exact nature of response you want from the audience.
It has three requirements:

• Central Idea 
• Clear and Concise message 
• It should be worded in term of the audience desire.

Steps in Organizing and Delivering the Speech

Organizing Speech: Jot down 3 or 4 main points that you want your audience to remember.
Summarize each idea in a single clear sentence: Sentences should be built around facts and supported by examples.

Write you speech: Use short and clear words. Don’t pronounce it with professional or technical jargons.

Use humour: Cracking a sensible joke or the adding a punchy one liners as per the environment. However, excess jokes can make the speaker sound unprofessional.

Write main points of Cue Cards/ Note Cards

Rehearse Your Speech: Time the delivery of speech while rehearsal to match the allotted time.

Look at the audience: Make an eye contact with the audience to make them realise that you are there for them.

Deliver your speech to the audience speak slowly and loudly (volume) when required. Stand upright in a relaxed manner with your feet slightly apart and hands by your side.

Visuals may be used where possible as it demonstrates certain points more effectively.

Audience Analysis

It is significant to communicate the purpose effectively.
Audience analysis means to discover the receiver’s view point so that the speaker can adopt his material directly to audience needs, wants, experiences and attitude.
Communication is a two way process involving the sender and the receiver. The heart of communication is in the change in behaviour.
As a public speaker, an analysis of audience is must to:

• Make the speech meaningful for them. 
• To gain support 
• To be understood 
• To establish a rapport with listeners

There are three phases in audience analysis. 

The first is adapting to your audience before you speak.
There are three ways to do this: demographic analysis, attitudinal analysis, and environmental analysis.
Demographic analysis involves age, gender, culture, ethnicity, race, religion, and educational level.
Attitudinal analysis addresses the audience's attitudes, beliefs and values.
Environmental analysis is the importance of seating arrangements, audience size, and room lighting, etc.

Importance of Audience Analysis

Audience is center to the communication process. The purpose of communication is to transfer the message with transmission of understanding among the audience.
Therefore good communication is always audience-centered. It is the audience that determines how one achieves the objectives of communication.

If the communicator fails to analyse the attitude, interests and knowledge of the audience, he is likely to be failure.
Why certain politicians with bad records can grab the votes? it is because their message strike to the waves of that time as well as wavelength of the public and consequently they can manage to manipulate public sentiments to their advantage.

Therefore, audience analysis is essential before designing the message.
Communication can take place only when the message is received in the same sense and spirit that sender intends to carry.
Therefore, the sender has to devise some common ground between him and the audience.
He has to choose the information that audience needs and finds interesting.
He should encode the message in words and other symbols that audience will understand easily.
Lastly, he should transmit the message along a channel that the audience will attend to.