Curing Consumers associate the majority of processed meat products like hams, bacon, and most sausages with an attractive pink or red color after heat treatment.. Curing of chopped/comm
Trang 5PREFACE
Research into English for Specific Purposes (ESP) has indicated its powerful tool within the teaching and learning of English for particular fields of study In particular, it plays a key role in meeting the needs of English students in ever-increasingly globalized contexts for business, education, science, and technology In line with this view, in Vietnam, ESP has been implemented in subject-specific teaching and curriculum initiatives and taught through English Lack of ESP proficiency is a real issue to prevent students from accessing and processing updated sources and knowledge, seeking scholarships or job opportunities in specialist fields although students can use English in their daily activities Therefore, ESP continues its role in helping students improve their knowledge and enhance their professional path
Although few textbooks on Food Science and Technology written in Vietnamese are still found available, numerous materials of specialized disciplines written in English are not widely read or used by Vietnamese students due to their insufficient English language proficiency This book is therefore designed to engage students’ interests and active participation in exploring the Food Science and Technology documents in English
This book is organized into six units Unit One introduces general techniques regarding meat processing Unit Two presents knowledge of fish processing Unit Three discusses fruit and vegetable processing Unit Four focuses on classification of milk processing Unit Five provides methods of milk processing Unit Six addresses technology of tea processing
We hope this book provides students with insights into their knowledge
of Food Science and Technology and assists them in expanding their vocabularies and academic writing styles
Although this book has been carefully planned and designed, its shortcomings are likely to be unavoidable We, authors of this resource, appreciate constructive comments from the staff, colleagues and students on refining it
THE AUTHORS
Trang 73.3 After reading the text 26
3.3.6 Writing a reflective journal entry 29
4.3.6 Writing a reflective journal entry 39
5.3.6 Writing a reflective journal entry 48
Trang 11Mixer and
blender
a machine used to mix sausage ingredient together
Nitrite the sodium salt added to curing mixture to form a cured
pink color and to inhibit C.botulinum growth
Pre-cooked meat cuts fully cooked and required reheating before
serving
1.2 Reading the text
Read the text Then do the exercises that follow the reading
Meat processing technologies include, on the one hand, purely technical processes such as:
Cutting, chopping, comminuting;
Salting and curing;
Utilization of spices and additives;
Smoking;
Fermentation and drying
These processes are described as following
CUTTING (reducing meat particle size)
There are five methods of mechanical meat cutting for which specialized machinery is used:
Mincing (grinding) of lean and fatty animal tissues
Larger pieces of soft edible animal tissues can be reduced in size by passing them through meat grinders Some specially designed grinders can also cut frozen meat, others are equipped with devices to separate “hard” tissues
Trang 13microbial inhibition and extension of the shelf-life of meat products by salt
in its concentrations used for food (on average 1.5-3% salt), is low
Curing
Consumers associate the majority of processed meat products like hams, bacon, and most sausages with an attractive pink or red color after heat treatment However, experience shows that meat or meat mixes, after kitchen-style cooking or frying, turn brownish-grey or grey In order to achieve the desired red or pink color, meat or meat mixes are salted with common salt (sodium chloride NaCl), which contains a small quantity of the curing agent sodium nitrite (NaNO2) Sodium nitrite has the ability to react with the red meat pigment to form the heat stable red curing color Only very small amounts of the nitrite are needed for this purpose
Curing of chopped/comminuted meat mixtures
Curing is applied for most chopped meat mixtures or sausage mixes for which a reddish color is desired The curing agent nitrite is added in dry form as nitrite curing salt The reaction of nitrite with the red meat pigment starts immediately Due to homogenous blending the meat pigments have instant contact with the nitrite Higher temperatures during processing, e.g
“reddening” of raw-cooked type sausages at 50°C or scalding/cooking of
other products at 70-80°C, accelerate the process
Curing of entire meat pieces
Besides the curing of chopped meat mixtures, entire pieces of muscle meat can be cured However, due to size the curing substances cannot instantly react with the meat pigments as is the case in chopped meat mixes Hence various curing techniques are applied
The final products of curing entire meat pieces are either cured raw fermented products or cured cooked products The curing system to be used depends on the nature of the final product (uncooked or cooked) There are two systems for curing entire meat pieces, dry curing and wet curing (“pickling”) and the type of the final product determines which system will
be used
SMOKING
Smoke for treatment of meat products is produced from raw wood Smoke is generated through the thermal destruction of the wood components lignin and cellulose The thermal destruction sets free more than 1000 desirable or undesirable firm, liquid or gaseous components of wood
Trang 151.3 After reading the text
1.3.1 Comprehending the reading Read the text and answer the questions
3 What impacts on color changes when processing meat? Be specific
4 How do people do to make meat color pink or reddish in final products? Which method is popularly applied, salting without nitrate or curing with nitrate?
5 Why do we need to add non-meat ingredients during meat processing? How important are they with regard to product quality?
6 What are the benefits and disadvantages of the smoking method for meat processing? Be specific
1.3.2 Recalling information Decide if each of the following statements is
true or false Write TRUE if the statement has a similar meaning with the information in the text Write FALSE if the statement contradicts the information
1 Meat processing technologies include chemical or biochemical processes such as salting and curing, using spices and additives, smoking, fermenting and drying
2 There are three methods of mechanical meat cutting as follows: grinding of lean and fatty animal tissues, chopping them in bowl cutter or chopping them in emulsifying machines
3 Beside adding to flavor and taste, salt also is an important functional ingredient in the meat industry, which assists in the extraction of soluble muscle proteins
4 Experience shows that meat or meat mixes, after kitchen-style cooking
or frying, turn pink or reddish color
5 There are two systems for curing entire meat pieces, dry curing and wet curing and the type of raw materials determine which system will be used
Trang 171.3.4 Talking it over In group (s) of four, discuss the following questions
1 What kinds of processed meat products are popular in your hometown? Which source is used for processing the local or imported products? Be specific
2 What would you recommend to partly replace meat with other protein sources in the diet? How do you develop novel products from imitated meat in the future?
1.3.5 Translation into Vietnamese In group(s) of four, translate one of the
following paragraphs
1 Paragraph “Meat processing technologies… as following”
2 Paragraph “Cutting… can be done manually.”
3 Paragraph “Salting/ curing… for this purpose.”
4 Paragraph “Curing of chopped/comminuted meat mixtures….which system will used.”
5 Paragraph “Smoking… preservation effect.”
6 Paragraph “Cold Smoking……ham products.”
1.3.6 Writing a reflective journal entry Write a short paragraph (50-80
words) to reflect on what you can learn about meat processing
1.4 Further reading
NON-MEAT INGREDIENTS
Along with the main components meat and animal fat, a wide range of substances of non-meat origin are used as ingredients in processed meat products Some of them are absolutely necessary, such as salt and spices Others are used for specific products
One way of categorizing non-meat ingredients is by source They are either chemical or plant or animal origin substances
Other classification criteria for non-meat ingredients are, whether they are additives or full foods (“food by itself”) or whether they have functional properties or not
Trang 19As another definition for specific non-meat ingredients, the term binder is used for substances of animal or plant origin, which have a significant high level of protein that serves for both water and fat binding Such substances include high-protein soy, wheat and milk products, such as soy isolate, wheat gluten, milk protein (caseinate) They are not extenders in the first place due to the low quantities added (approx 2%), but act through their high quality proteins that are instrumental in water binding and protein network structuring On the other hand, some substances with little or no protein level, like starches and flours mentioned above under “fillers”, can bind water and fat by means of physical entrapment and could also be considered “binders”
In order to provide an overview of the most common substances used as non-meat ingredients, they are listed hereunder according to their origin, namely chemical or of animal or plant origin
Chemical substances used as ingredients
There are various chemical substances approved for the different kinds of food processing, but in the specific case of meat processing the number of approved chemical substances is rather limited in most countries The following are of significance:
• Salt (for taste, impact on meat proteins, shelf-life)
• Nitrite (for curing color, flavor, shelf-life)
• Ascorbic acid (to accelerate curing reaction)
• Phosphates (for protein structuring and water binding)
• Chemical preservatives (for shelf-life)
• Antioxidants (for flavor and shelf-life)
• Monosodium glutamate MSG (for enhancement of flavor)
• Food coloring substances (synthetic and of plant origin)
Non-meat ingredients of animal origin
Ingredients of animal origin are not commonly applied but may be useful for specific meat preparations They all have functional properties (except whole milk), in particular improvement of water binding and prevention of fat separation during heat treatment Apart from their functional properties, some of them can also be considered meat extenders, as mentioned below
• Milk caseinate (90% protein; used in small quantities (2%); have functional water and fat binding properties)
Trang 21UNIT TWO: FISH PROCESSING
“You don’t need a silver fork to eat good food.”
- Paul Prudhomme -
2.1 Before reading the text
Previewing the topic Discuss the possible answers to following questions
about fish processing
1 How often do you have fish in your diet? Which do you prefer- fresh fish
Boneless a fillet that has all the bones removed
Freezer Burn dry, white crumbly spots on frozen fish caused by
dehydration and drying when inadequately protected
Fresh fish kept chilled on ice but not deep frozen
Glaze a coating of ice on frozen seafood to protect it from
dehydration and oxidation during cold storage
Grading the process of sorting fish into similar sizes
Fillet a slice of boneless meat or fish
Finning a process of removing fins from fish
Soaked a product that has had water added to it by using STP
Steak a cross-section of a fish, containing the backbone
(smaller fish, salmon and halibut); boneless portions cut from a loin (larger fish, tuna and swordfish)
Rigor Mortis temporary stiffening of muscles following death Fish
should be processed either pre- or post-rigor, as handling during rigor can cause gaping of the flesh
Trang 23very important for fish processing such as smoking, freezing, heat treatment, salting, etc as well as for marketing
Removal of slime
Slime accumulating on the skin surface of dying fish is a protection mechanism against harmful conditions In some freshwater species slime constitutes 2-3% of body weight Slime excretion stops before rigor mortis Slime creates a perfect environment for micro-organism growth and should
be removed by thorough washing Eel, trout and carp require special care with regard to slime removal Even small amounts of slime, which frequently remain after manual cleaning, result in visible yellowish-brown spots
Washing
Washing is intended primarily to clean the fish and to remove accumulated bacteria The effectiveness of the washing procedure depends, inter alia, on the kinetic energy of the water stream, ratio of fish volume to water volume and on the water quality A proper fish: water volume ratio for achieving the desired level of cleanliness is 1:1, however, in practice more water is usually used (twofold) Washing of gutted and headed fish should be done
on termination of the processing operation
Beheading
The head constitutes 10-20% of the total fish weight and it is cut off as an inedible part Although many mechanized beheading machines had been developed for processing marine fish, freshwater fish are usually beheaded manually The main reason is the lack of inexpensive equipment offering minimal tissue loss during this procedure
Trang 25Meat-bone separation
In recent years a new trend has emerged to effectively process raw fish products which resulted in production of minced meat separated from inedible parts, such as bones, skin and scales During filleting a considerable amount of meat is usually left along the ribs and backbone (30-50%) The carcasses are a source of minced meat Minced meat is also produced from less valuable fish species after beheading, their body cavities carefully cleaned and kidney tissue removed Meat is separated from the bones, skin and scales, in automated devices called separators
2.3 After reading the text
2.3.1 Comprehending the reading Read the text and answer the questions
3 How do people stun fish before processing? Which method is preferred,
using an electric current or cutting the aorta and bleeding to death?
4 Why do we need to remove slime? What happens if there is no slime removal until skinning?
5 What should we do to control quality during processing? Which factor needs to be checked regularly?
6 What are the benefits and disadvantages of using machines for preliminary processing of fish? Be specific
2.3.2 Recalling information Decide if each of the following statements is
true or false Write TRUE if the statement has a similar meaning with the
information in the text Write FALSE if the statement contradicts the information
1 Preliminary processing of freshwater fish usually consists of the following steps: evisceration, beheading, scaling, filleting, skinning and grinding skinned fillets
2 Size grading is not necessary for fish processing such as smoking, freezing, heat treatment, salting
Trang 272 What do you recommend to increase the value of shutchi catfish (cá tra)
in the international markets? How do you develop novel products from shutchi catfish in the future?
2.3.5 Translation into Vietnamese In group (s) of four, translate one of
the following paragraphs
1 Paragraph “Preliminary processing… similar end-products.”
2 Paragraph “Stunning of fish… for marketing.”
3 Paragraph “Removal of slime… body axis.”
4 Paragraph “Washing… gall bladder.”
5 Paragraph “Cutting away the fins… marine fish.”
6 Paragraph “Skinning…… separators.”
2.3.6 Writing a reflective journal entry Write a short paragraph (50-80
words) to reflect on what you can learn about fish processing
2.4 Further reading
QUALITY CONTROL
Traditional control is limited to controlling the final product Practice has proved that this is not enough and quality control must be carried out at all stages of production, starting from the contract of supplying of raw materials, through all stages of processing, to storing and delivering the final products Such an approach is not about quality control but quality assurance, covering the entire production chain Below, the principles related to quality control are presented regarding the main individual activities and processes in fish processing
Drawing up a contract for raw material supply
Raw material supply contracts should cover all specific requirements, for example: fish size, closed season, level of chemical contaminants in the fish and in the water from which fish comes and chemical measurements must
be conducted by an organization that has environmental monitoring transactions Sometimes, especially in the case of export, the buyer / customer may have additional needs, for example, an indication that the level of chemical contaminants is different from the standard The buyer should ensure that he / she will receive a health certificate for his raw materials and that the certificate has been issued by official control
Trang 29should be considered by the receiver when the contract is prepared The final result of quality control of raw material is decisive with respect to further procedure during fish processing Generally, when fish is qualified
as conforming with requirements and cooled properly it is placed in cold stores or transported direct to the processing line Ice is added to fish cooled insufficiently and this is placed in cold store The temperature inside the cold store should be close to 0° C and should be continuously recorded If temperature cannot be registered automatically, measurements should be taken not less frequently than every two hours
Quality control during the production process
The quality control program during the production process depends on the profile of production carried out in the processing plant Each processing plant must draw up a flow chart of the entire process starting from the raw material through every individual operation and process to the final product and with all quality control points indicated Criteria for selection of control points depend on potential hazards which, in the case of lack of proper handling, can cause a risk for both the food and the consumer For example, control of temperature during individual operations, their duration, concentration of food additives, etc., are typical and critical parameters measured at control points
Technological supervision is responsible for use of adequate processing parameters Quality control personnel are responsible for monitoring these parameters and in the case of deviation they should undertake proper corrective action
The final step in production control is the quality control of the final product according to technical requirements and specifications included in the contract or standards if the latter are compulsory Such assessment is carried out according to approved procedures with special regard to health quality requirements pertaining in a given country This type of control will disappear in the future because an introduction of quality assurance systems,
as a continuous control throughout the entire processing procedure, will eliminate this traditional form of control
Quality control personnel are also responsible for supervision of assurance
of cleanliness and disinfection of production lines and processing rooms Maintenance of cleanliness and disinfection should be carried out in accordance with a program approved by the local veterinary service The quality control staff assures adherence to this program which especially concerns:
Trang 31UNIT THREE: FRUIT AND VEGETABLE PROCESSING
“Food is symbolic of love when words are inadequate.”
- Alan D Wolfelt -
3.1 Before reading the text
Previewing the topic Discuss the possible answers to following questions
about fruit and vegetable processing
1 How often do you have fruits and vegetables in your diet? Which do you prefer, fresh produce (fruits and vegetables) or processed ones?
2 Why do we have to process fruits and vegetables? What kind of foods can be produced from these materials? Be specific
3 What are the most popular fruits in your hometown? What do people do
to make popular fruits known in the international market?
Vocabulary
Term(s) Meaning(s)
Case hardening the formation of a dry skin on a wet food due to
over-rapid drying It slows the rate of drying and can lead to spoilage during storage
Blanching a heat treatment by hot water or steam in order to
inactive enzyme
Cross contamination the transfer of soils or micro-organisms from raw
food to processed food
Enzymes natural proteins in foods that can cause changes in
color, flavor or texture
Emulsifying agent a chemical that stabilizes an emulsion and prevents
it separating into its component parts
High-acid foods food with a pH < 4.5 that cannot support the growth
of food-poisoning micro-organisms
Low-acid foods foods that have little acid and therefore can contain
food poisoning bacteria if poorly processed
Micro-organisms tiny forms of life, invisible until they are in large
numbers, including moulds, bacteria and yeasts
Trang 33eliminate spoiled fruit before washing in order to avoid the pollution of washing tools and/or equipment and the contamination of fruit during washing
Washing efficiency can be gauged by the total number of micro-organisms present on fruit surface before and after washing - best result are when there
is a six-fold reduction The water from the final wash should be free from moulds and yeast; a small quantity of bacteria is acceptable
Fruit washing can be carried out by immersion, by spray/ showers or by combination of these two processes which is generally the best solution: pre-washing and washing Some usual practices in fruit washing are:
Addition of detergents or 1.5% HCl solution in washing water to remove traces of insect-fungicides;
Use of warm water (about 50°C) in the pre-washing phase;
Higher water pressure in spray/shower washers
Washing must be done before the fruit is cut in order to avoid losing high nutritive value soluble substances (vitamins, minerals, sugars, etc.)
Sorting
Fruit sorting covers two main separate processing operations:
Removal of damaged fruit and any foreign bodies;
Qualitative sorting based on organoleptic criteria and maturity stage
Mechanical sorting for size is usually not done at the preliminary stage The most important initial sorting is for variety and maturity However, for some fruit and in special processing technologies it is advisable to proceed to a manual dimensional sorting
Trimming and peeling (skin removal)
This processing step aims at removing the parts of the fruit which are either not edible or difficult to digest especially the skin Up to now the industrial peeling of fruit and vegetables was performed by three procedures:
Mechanically;
By using water steam;
Chemically; this method consists in treating fruit and vegetables by dipping them in a caustic soda solution at a temperature of 90 to 100° C; the concentration of this solution as well as the dipping or immersion time varying according to each specific case
Trang 35Fruit slices are dipped in the solution for about two to three minutes and then removed so as not to absorb too much SO2 Then the slices are allowed
to stand for about one to two hours so that the SO2 may penetrate throughout the tissues before processing
Sulphur dioxide is also used in fruit juice production to minimize oxidative changes where relatively low heat treatment is employed so as not to damage delicate juice flavor
Dry sulphuring is the technological step where fruit is exposed to fumes of
SO2 from burning sulphur or from compressed gas cylinders; this treatment could be used in the preparation of fruits (and some vegetables) prior to
drying / dehydration
Sugar syrup
Sugar syrup addition is one of the oldest methods of minimizing oxidation
It was used long before the causative reactions were understood and remains today a common practice for this purpose
Sugar syrup minimizes oxidation by coating the fruit and thereby preventing contact with atmospheric oxygen Sugar syrup also offers some protection against loss of volatile fruit esters and it contributes sweet taste to otherwise tart fruits It is common today to dissolve ascorbic acid and citric acid in the sugar syrup for added effect or to include sugar syrup after an SO2
treatment
3.3 After reading the text
3.3.1 Comprehending the reading Read the text and answer the questions
3 Why do we need to wash fruits before processing? What happens if there
is no washing until peeling (skin removal)?
4 What do people do to minimize fruit oxidation after peeling or cutting? Which method is better, using chemicals or sugar syrup? Be specific
5 What should we do to retard color changes during fruit and vegetable processing? Which factor needs to be considered most?
Trang 37For example, a particular variety of fruit which may be excellent to eat fresh
is not necessarily good for processing Processing requires frequent handling, high temperature and………(2)
Many of the ordinary table varieties of tomatoes, for instance, are not suitable for making ……….(3) or other processed products A particular mango or ……….(4) may be very tasty eaten fresh, but when
it goes to the processing center it may fail to stand up to the processing requirements due to variations in its quality, size, ……….(5), variety and so on
Even when a ……….(6) can be processed, it is not suitable unless large and regular supplies are made available An important processing center or a factory cannot be planned just to rely on ……… (7) gluts; although it can take care of the gluts it will not run economically unless regular supplies are guaranteed
To operate a fruit and ………(8) processing center efficiently it is of utmost importance to pre-organize growth, ………(9) and transport
of suitable raw material, either on the nucleus ……… (10) basis or using out growers
3.3.4 Talking it over In group(s) of four, discuss the following questions
1 What are the potential fruits and vegetables that can be exported from your hometown? What kind of industrial foods can be produced? Be specific
2 What would you recommend to diversify products from local fruits and vegetables? What do you do to promote those local products worldwide?
Be specific
3.3.5 Translation into Vietnamese In group(s) of four, translate one of the
following paragraphs
1 Paragraph “Fruit reception… medium processing units as well.”
2 Paragraph “Washing… minerals, sugars, etc.”
3 Paragraph “Sorting… each specific case.”
4 Paragraph “Cutting… from the system.”
5 Paragraph “Sulphur dioxide treatment… prior to drying / dehydration.”
6 Paragraph “Sugar syrup… SO2 treatment.”
Trang 39Manufacturing of jellies
BASIC RECIPE SETTING is done starting with equal parts in weight
of sugar and juice (for example 1000 g juice and 1000 g sugar) As final jelly has to contain about 60% added sugar, weight of finished product must be of about 1600 g, by evaporation of about 400 g of water
BOILING is carried out as following: juice is boiled up to removal of about half of the water that has to be evaporated, then the calculated sugar quantity is added gradually; the remainder of the water is evaporated until a concentration in soluble substances of 65-67% is reached, in which is incorporated also the sugar from juice
During boiling it is necessary to remove foam / scum formed Product acidity must be brought to about 1% (malic acid) corresponding to pH
> 3 Any acid addition is performed always at the end of boiling
For juices rich in pectin, jellification will occur without pectin addition If at the trial boiling test the jellification has not occurred, because of pectin absence, in this case 1-2% powder pectin will be added by operating as indicated: pectin is mixed with 10-20-fold sugar quantity and is introduced directly in the partially evaporated juice and then boiling is conducted rapidly up to final point Evaluation of final point is done not only by refractometry but also by jellifying test
A rapid test for evaluation of juice pectin content is possible by mixing a small sample of juice with an equal volume of 96% alcohol; the apparition of a compact gelatinous precipitate indicates sufficient pectin content for jellification
Boiling of jellies is performed in small batches (25-75 kg) in order to avoid excessively long boiling time which brings about pectin degradation
COOLING is optional and is carried out up to 850C, in double wall baths with water circulation
FILLING is performed at a temperature not below 850C in receptacles (glass jars, etc.), which must be maintained still about 24 hours to allow cooling and product jellification
RECEPTACLE CLOSING is done after product jellification
Usual jelly types are: quinces, strawberries, cherries, wild berries, alone or
in mixes with apples