SCIENTIFIC DISCOURSE GRAMMAR
By Irene Voulgaris
In these blog posts I will mainly examine the grammar, structure and
rhetorical markers used in each part of a scientific paper, making
reference to relevant academic writing conventions in the process.
Although I intend to focus mainly on the grammar of written scientific
discourse, brief reference to useful reading and writing skills will also be
made whenever it is deemed appropriate.
An authentic published paper on food-technology 1
Let’s take a look at a paper describing starter cultures for cheese
processing. It forms a chapter of a book in the area of food technology
and I have uploaded it as a pdf file on the same blog post.
The paper is entitled:
“Lactic Acid Bacteria as Starter-Cultures
Processing:Past, Present and Future Developments”
for
Cheese
and it has been written by
J. Marcelino Kongo
Previewing the paper
It is always wise to see what the paper is about by previewing it first; that
is, by reading only its title, its abstract or its introduction, its subtitles and
its conclusion. In this way, you will quickly get an idea of its topic and
how this topic is developed throughout the paper, without reading it all.
The paper’s organization
The paper consists of the following parts :
1. Introduction
1
The open access paper has been downloaded from http://dx.doi.org/10.5772/55937
1
2. Lactic acid bacteria in dairy processing
2.1. LAB as starter-cultures in cheese processing
2.2. LAB food safety and cheese technology
3. Development of new starter cultures for cheese processing
3.1. EPS-producing cultures and acceleration of cheese ripening
3.2. Methods used to characterize LAB for starter cultures development
4. Concluding remarks
Author details
5. References
After previewing the paper, read it carefully in order to understand
not just the main points made, but also the detailed information the
writer offers us.
Previewing and careful reading of the whole paper has enabled us to
understand its information. So having understood its contents, we
will analyze each part of the paper, this time focusing on its discourse
grammar.
Let’s start with the paper’s introduction:
Introduction
The identification of solutions to improve the life and health of
consumers, providing safe and nutritious foods, is the major concern in
Food Science. Toward that goal, preservation methods such as salting,
drying, high/low temperature application, fermentation, and more
recently, pulsed electric field, high pressure and radiation –alone or in
combination –are applied. The chosen method depends on various factors
2
such as the type of raw materials, availability of the method, cost,
effectiveness and degree of change it causes to the flavour and nutritional
features of the food product. Fermentation, which is also called
biopreservation, is a cheap, widely accessible method that meets today’s
increasing consumers’ demand for minimally processed/preserved food
products. Biopreservation with lactic acid bacteria (LAB) is indeed one of
the oldest and highly efficient forms of non-thermal processing methods.
Cheese production is based on the ability of lactic acid bacteria to ferment
sugars, especially glucose and galactose, so to produce lactic acid and
aroma substances that give typical flavours and tastes to fermented
products. Lactic acid bacteria also release bacteriocins, antimicrobial
metabolites, which are considered safe and natural preservatives, with
great potential to be used on their own, or synergistically with other
methods in food preservation.
Notes on the grammar and structure of the paper’s introduction
Present simple tenses for descriptive texts
Read the introduction. What does the writer do in the introduction?
In the introduction of the paper the writer refers to the role of food
technology today, to existing food preservation methods and to the
method of biopreservation with lactic acid bacteria in particular, as the
optimum method for cheese production. Thus, the writer’s intention in the
introduction is informative and descriptive. After making a brief
3
reference to contemporary food preservation methods, he focuses on one
such method in particular: biopreservation with lactic acid bacteria.
Which verb tense does the writer use?
Now, let’s take a look at the verb tenses the writer has used to inform us
about these methods and to briefly describe them.
All sentences in the paper’s introduction contain verbs in the present
simple tense. Some of these tenses are in the active voice and I have
highlighted them in yellow, while others are in the passive. I have both
highlighted and underlined the verbs which are in the passive voice.
The writer has used the present simple tense to tell us what preservation
methods are available today, which one is the most suitable for optimum
cheese production, and what this method is like. Thus, basically, the
present simple has been used to describe things existing today and the
text is a descriptive one.
In general, we use the present simple with descriptive texts which refer to
the present.
When is the passive present simple used in descriptive texts?
When we do not need to mention the fact that the human factor is the
agent of an action or process (as is indeed the case in scientific discourse)
we use the passive present simple tense instead of the active. For
example, in the sentence “Fermentation, which is also called
biopreservation,…” the writer has used the passive present simple tense
“is called” because fermentation is also called “biopreservation” by
people. The agent “by people” does not need to be mentioned. In
conversational English, one could say the same by using the active
present simple: “Some people also call fermentation “biopreservation”.
Impersonal style in scientific writing
When you write a scientific paper, there are specific linguistic
conventions that you should follow. One of these conventions is to sound
4
as impersonal as possible by avoiding the use of the active voice and by
using the passive. Therefore, the use of the passive is the norm in
scientific discourse.
It is not difficult to figure out why this convention has been established in
academic writing in scientific disciplines. Given the fact that the human
factor has always been the agent of experiments, of man-made/industrial
processes and of scientific discourse in general, scientists are not
concerned with e.g. who does an experiment or with who controls a
process. Instead they focus on the experiment or on the process itself.
This is why they use the passive voice without mentioning the agent; that
is, without mentioning the scientist (agent) who does the experiment or
who controls the process. It would sound too repetitive if they did.
Exercises
1. What does the expression “toward that goal” in the 3rd line refer
to?
2. Which preservation methods are used for producing healthy and
wholesome foods?
3. Name the factors which must be taken into consideration when
making the choice of preservation method.
4. Define “biopreservation”.
5. In what ways do lactic acid bacteria act during the process of
fermentation?
Notes on discourse markers (also called linking words or linking
devices)
a. back reference discourse markers
To refer to something we have mentioned earlier in a text we use back
reference discourse markers. These are words or phrases that refer back to
something we have already mentioned. For example, the phrase “Toward
5
that goal” in the 3rd line serves this purpose. The writer used it to refer
back to the goal of food science mentioned in the previous sentence:
“The identification of solutions to improve the life and health of
consumers, providing safe and nutritious foods, is the major concern in
Food Science. Toward that goal, preservation methods such as…”
[In the paragraph above I have used the word “it” in the 4 th line to refer
back to the expression “Toward that goal”.]
In this way, we avoid repetition and the text becomes more cohesive.
b. enumeration discourse markers
When we provide a list in order to illustrate the various specific forms a
more general term, a cover term, encompasses, then we enumerate them;
that is, we name them one by one, separated by commas, sometimes after
the expression “such as”. In such cases, “such as” is an enumeration
marker. The expression “such as” lets the readers know that we are going
to offer them a list of relevant forms. We also enumerate when we want
to provide a list of factors/solutions/causes/consequences/results, etc.
There are the following instances of enumeration in the text:
preservation methods(cover term) such as(enumeration marker) salting,
drying, high/low temperature application, fermentation, (enumeration)
and more recently, pulsed electric field, high pressure and radiation
(enumeration) –alone or in combination – may be applied.
The chosen method depends on various factors (cover term) such
as(enumeration marker) the type of raw materials, availability of the
method, cost, effectiveness and degree of change it causes to the flavour
and nutritional features of the food product.(enumeration)
Notes on sentence structure
non-defining relative clauses
6
“Fermentation, which is also called biopreservation, (non-defining
relative clause) is a cheap, widely accessible method that meets today’s
increasing consumers’ demand for minimally processed/preserved food
products.”
Non-defining relative clauses are separated from the rest of the sentence
by commas. They contain additional information about the subject or the
object of the sentence; this information is not essential in order to
understand the meaning of the sentence. It is just extra information.
apposition
Apposition is usually a noun phrase separated by commas which appears
immediately after another noun or noun phrase. Both of these noun
phrases refer to the same person or object.
There are the following instances of apposition in the text:
Cheese production is based on the ability of lactic acid bacteria to ferment
sugars (noun), especially glucose and galactose, [noun phrase
introduced with “especially”& also apposition introduced with
“especially” for expressing particularization; in our case particular
kinds of sugars] so to produce lactic acid and aroma substances that give
typical flavours and tastes to fermented products. Lactic acid bacteria also
release bacteriocins (noun), antimicrobial metabolites, (noun phrase &
also apposition for providing a synonym for “bacteriocins” which is
more easily understood: “antimicrobial metabolites”) which are
considered safe and natural preservatives, with great potential to be used
on their own, or synergistically with other methods in food preservation.
Let’s move to the 2nd part of the paper now :
2. Lactic acid bacteria in dairy processing
Milk is a highly perishable food raw material, therefore (linking word
signalling result), its transformation in cheese or other form of fermented
dairy product provides an ideal vehicle to preserve its valuable nutrients
(Table 1), making them available throughout the year. It is known (
7
impersonal passive present simple used instead of the active present
simple “we know”) that while (linking word signalling contrast)
unprocessed milk can be stored for only a few hours at room
temperatures, cheeses may reach a shelf-life up to 5 years (depending on
variety).
Fermentation with lactic acid bacteria (LAB) is a cheap and effective
food preservation method that can be applied even in more rural/remote
places, and leads to improvement in texture, flavor and nutritional value
of many food products. LAB have a long and safe history of application
and consumption namely (linking word signalling a specific example) in
cheese processing (Aquilanti et al., 2006, Caplice & Fitzgerald, 1999,
Giraffa et al., 2010, Ray, 1992; Wood, 1997; Wood & Holzapfel, 1995)
thus (linking word signalling result) being generally regarded as safe
(GRAS). Increasing knowledge of LAB physiology, together with new
developments in processing technology, is leading to their application
8
beyond traditional starter culture application, namely (linking word
signalling specific cases/examples) in new food safety roles and direct
health applications.
2.1. LAB as starter cultures in cheese processing
Cheese-making is based on application of LAB in the form of defined or
undefined starter cultures that are expected to cause a rapid acidification
of milk through the production of lactic acid, with the consequent
decrease of pH, thus (linking word signalling result) affecting a number
of aspects of the cheese manufacturing process and ultimately (linking
word signalling reinforcement/emphasis) cheese composition and quality
(Briggiler-Marco et al., 2007).
[Below the writer describes how cheese used to be produced in the past.
This is why he uses simple past tenses which I have highlighted in blue.]
The earliest productions of cheeses were based on the spontaneous
fermentation, resulting from the development of the microflora naturally
present in the raw milk and its environment. The quality of the end
product was a reflex of the microbial load and spectrum of the raw
material. Spontaneous fermentation was later optimized through
backslopping, i.e., inoculation of the raw material with a small quantity of
whey from a previously performed successful fermentation, and the
9
resulting product characteristics depended on the best-adapted strains
dominance (Leroy & De Vuyest, 2004).
[Below the writer returns to the present time, so he uses simple present
verb tenses once again.]
Today, backslopping is still used to produce many artisanal raw-milk
cheeses, namely (linking word signalling a specific example) those
bearing the PDO (Protected Designation of Origin) status, which are
considered to be an important source of LAB genetic diversity, as well as
(linking phrase signalling addition) being crucial from an economic and
even ecologic point of view, since (linking word signalling reason)
production of said cheeses (usually processed on a small-scale)
contributes to local employment and maintains people functioning as
“guardians of local environment” in regions that otherwise would be
deserted.
The starter-culture (which is) applied in this, so-called, natural
fermentation, is usually a poorly-known microflora mix that although
having a predominance of LAB, may also contain non-LAB
microorganisms, and its microbial diversity and load is usually variable
over time. In fact, studies directed to characterize traditional cheeses
show that those (which are) made from raw milk harbor a diversity of
10
LAB (Bernardeau et al., 2008) depending on geographical region, where
a few may show particular interesting technological features that upon
optimization may have industrial applications (Buckenhiiskes, 1993). For
example, because (linking word signalling reason) wild strains need to
withstand the competition of other microorganisms to survive in their
hostile natural environment, they often produce antimicrobial substances
(which are) called bacteriocins (Ayad et al., 2002), which are natural
antibacterial proteins that can be incorporated directly into fermented
foods as such (food-grade) or indirectly as starter culture (Bernardeau et
al., 2008). Although (linking word signalling
contrast) nisin is today
the only bacteriocin that has reached commercial status, approved
worldwide as a natural food preservative, many other bacteriocins may
soon reach similar status. Recently, our work (to be published) with LAB
isolates from traditional portuguese raw-milk cheeses, revealed several
lactobacilli having antibacterial activity against pathogens such as
(linking word signalling exemplification) Listeria monocytogenes,
Staphyloccus aureus, Salmonella newport and even E. coli. Future studies
may allow us using these isolates or their metabolites, applied in situ or
ex situ fashion, in applications where food safety is a concern.
Moreover, traditional cheeses also obtain their flavor intensity also from
the non-starter lactic acid bacteria (NSLAB), which are not part of the
11
normal starter flora but develop in the product, particularly during
maturation, as a secondary flora (Beresford, et al., 2001). The isolation
and optimization of wild-type strains from traditional products, to be used
as starter cultures in cheese processing, is indeed a highly active field of
research in Food Science today.
2.2. LAB food safety and cheese technology
Cheese is made in almost every country of the world and (linking word
signalling addition which will not be emphasised in the rest of the paper
as it is very common there are more than 2000 varieties which are made
from milk of several mammals, and are processed industrially or by
traditional methods.
However(linking word signalling contrast), despite (linking word
signalling constrast) the large number of varieties, the basic steps which
are required in any cheese processing are essentially the same, and slight
variations in any of these steps may result in products of different general
quality (Figure 2).
Milk treatment. In large-scale cheese processing, the milk is heated, e.g.
73°C for 15 seconds, to destroy pathogens and reduce microbial numbers,
while (linking word signalling contrast) in most traditional Protected
Designation of Origin raw-milk cheeses heat treatment is not applied.
Also (linking word signalling additional information) the milk may be
12
standardized, i.e. the fat content may be increased or (linking word
signalling alternative way) reduced, or the casein-to-fat ratio may be
adjusted.
Starter-culture addition. The type of commercially available starter
preparation to be used is determined by the cheese recipe. As previously
stated (back reference clause) , large-scale processing relies on using
defined, commercially available starters, while (linking word signalling
contrast)for traditional cheeses, a natural fermentation (whey from the
previous lot) is often used.
Milk treatment
Coagulation
Whey draining
Salting/Pressing
Ripening
Figure 2. Common steps to most cheese making processes
Coagulation. During (linking word signalling duration, length of time)
coagulation, modifications on the milk protein complex occur under
13
defined conditions of temperature and by action of a coagulant agent,
which changes the physical aspect of milk from liquid to a jelly-like
mass. Various coagulants are available, e.g. (abbreviation signalling
exemplification) lemon juice, plant rennet or more commonly a
proteolytic enzyme such as (linking device signalling exemplification)
chymosin (rennin) or (linking word signalling alternative way)– due
to(linking device signalling reason) high demand from the cheese
industry – proteolytic enzymes from the mould Rhizomucor miehei that
are obtained via biotechnology. These enzymes (back reference noun
phrase) have an acidic nature, meaning they (back reference word) have
optimum activity in a slightly acidic environment. Therefore (linking
word signalling result), the action of lactic acid bacteria in this
phase(back reference noun phrase) is crucial as (linking word signalling
reason) they (back reference word) are required to rapidly release enough
lactic acid, to lower the milk pH from 6.7 to near 6.2, (thus (linking word
signalling result)
creating an appropriate environment for optimum
activity of rennin) and later to pH 4.5 as (linking word signalling process
progression)
the
processing
proceeds,
creating
an
inhospitable
environment for many unwanted bacteria, thus (linking word signalling
result) increasing the end product safety.
14
Cutting the coagulum. The resulting coagulum is cut with appropriate
knives into curd particles of a defined size, e.g. 1-2 cm, or it (back
reference word) is transferred into containers or cheese moulds. The
cutting or ladling of the coagulum is a very important step in the
manufacture of some cheese varieties as (linking word signalling reason)
it (back reference word) determines the rate of acid development and the
body (firmness) and texture of the cheese.
Heating or cooking the curds. Heating (37-45°C, depending on the type
of cheese) the curds and whey affects the rate at which whey is expelled
from the curd particles and the growth of the starter microorganisms.
During (linking word signalling duration) heating, the curds and whey are
often stirred to maintain the curd in the form of separate particles.
Whey removal. After heating and stirring (linking phrase signalling
succession), and when the curd particles have firmed and the correct acid
development has taken place, the whey is removed allowing the curd
particles to mat together.
Milling the curd. In cheeses such as (linking device signalling
exemplification) Cheddar, when the curd has reached the desired texture,
it (back reference word) is broken up into small pieces to enable it (back
15
reference word) to be salted evenly. Milling the curd is done either
(linking device used in conjunction with ‘or’ denoting one of two ways,
etc) by hand or mechanically. Salting is usually done to enhance the taste
of the curd and to increase its (back reference word) safety and shelf life.
Ripening. Finally (linking word signalling the last step of the process),
for most cheeses, the resulting mass is molded and (it is) put to ripening
for periods that vary from 15 days to one, two or more years. Ripening is
a slow phase, crucial for the development of aroma and flavor, which is
brought about by the action of the many enzymes which are released by
the lactic acid bacteria. During (linking word expressing duration)
ripening the protein in cheese is broken down from casein to low
molecular weight peptides and amino acids. Proteolysis is the major – and
certainly the most complex of biochemical events that take place during
(linking word expressing duration) ripening of most cheese varieties and
lactic acid bacteria play an important role in it (back reference word).
This (back reference word) happens while (linking word meaning during
the time when something happens) the cheeses are stored in the curing
cabinets and in some cases in caves, usually with temperature and
humidity controlled.
16
During (linking word signalling duration) coagulation, the initial step of
casein hydrolysis is performed by chymosin (milk coagulant) and
proteinases from starter lactic acid bacteria, starter moulds and other
microorganisms. The further degradation of high molecular weight
peptides which are produced at the initial step, is subsequently (linking
word denoting succession) catalised to low molecular weight peptides by
endopeptidases from the lactic acid bacteria during (linking word
signalling duration) ripening (see Fig. 4 and 5).
17
Primary proteolysis in cheese is defined as changes in β-, γ-, ascaseinpeptides, and other minor proteins that are detected by PAGE
(Figure 6). Primary proteolysis leads to the formation of large waterinsoluble peptides and smaller water-soluble peptides (Fox, 1993,
18
Mooney et al., 1998). Secondary proteolysis products include those
peptides, proteins and amino acids (forward reference noun phrase) which
are soluble in the aqueous phase of cheese and are extractable as (linking
word signalling exemplification) the water-soluble nitrogen (WSN)
fraction. The WSN fraction is a complex mixture of large, medium, and
small peptides and amino acids. These components (back reference noun
phrase) result from the action of milk clotting enzymes, milk proteases,
starter lactic acid bacteria and contaminating microorganisms (Rank et
al., 1985).
19
20
21
During (linking word signalling duration) processing, the pH history of
the cheese is a good indicator of the actual product safety. For example
(linking device signalling exemplification) a ‘slow vat’ allows more time
at high pH for undesirable bacteria to grow, while (linking word
signalling contrast) during (linking word signalling duration) cheese
ripening, unwanted bacteria may grow due to an acidity neutralization
resulting from secondary microflora growth such as (linking device
signalling exemplification) moulds. For most ripened varieties the
combination of a low pH and ripening time, which leads to moisture
decrease in the cheese, will in general (linking device meaning ‘in most
cases’) cause a gradual decline of all groups of bacteria due to (linking
device signalling reason) increasing inhospitable conditions inside the
cheese.
The pH history of a cheese and the hygienic practices which are applied
in its (back reference word) manufacture are thus(back reference linking
word) key factors to guarantee safe products. Thus, (back reference
linking word) the isolation of autochthonous lactic acid bacteria to be
used for the development of specific starter cultures with improved acid
production and other antimicrobial activities may be an excellent way
towards reaching the goals of simultaneously obtaining safe traditional
cheeses, which are still bearing their unique flavours.
22
Nowadays, western consumers still enjoy artisan cheeses thanks to their
outstanding gastronomic qualities; however(linking word signalling
contrast), in most industrialized countries the large-scale cheese
processing is the most important branch of the food industry. In such
cases (back reference expression), there is a strong need to control the
fermentation process towards maximum efficiency in terms of yields and
standardization of the end product. This (back reference word), and the
need to fulfill the safety assurance of the final product, is usually
achieved by, among other improvements, adding a high dosage of pure
lactic acid bacteria selected starter cultures, which are commercially
available (today’s world starter culture market is more than US $1
billion), as well as (linking device adding information) by heat treating
the raw milk, most commonly by pasteurization.
Notes on the grammar and structure of the 2nd part of the paper
The text type and its logical structure
The writer provides us with more detailed descriptions of preservation
methods in the 2nd part of the paper and he also describes the general
process of cheese making in detail. As it is common with every mancontrolled or machine-controlled process, there is extensive use of the
passive present simple tense. I have highlighted the passive present
simple tenses in yellow and I have also underlined them. Active present
simple tenses have only been highlighted in yellow.
23
Exercise
Read this part of the paper and expand Figure 2 which depicts the general
process of cheese making, to briefly describe each stage of the process.
Use mainly the passive present simple.
Answer:
The process of cheese making
Milk treatment: Milk is heated to 73° C. It may be standardized, i.e its
fat content may or (it may be) reduced.
Adding starter culture: Commercially produced starter culture is added
to the milk in industrially produced cheese. Natural starter culture is
added to the milk in traditionally produced cheese.
Coagulation: Milk coagulates, that is, it turns from a fluid state to a
semi-solid state due to its chemical transformation with the starter
culture.
Cutting the coagulum:The coagulated milk mass, the coagulum, is cut
with special knives in small cubes, called curds.
Cooking the curds: The curds are heated to 37-45° C.
Whey draining: The curds are drained from the whey.
Milling the curds:The curds are milled into tiny pieces in some types of
cheese.
Salting/Pressing: Salt is added to the drained curds and then they are
pressed in moulds.
24
Ripening: Cheese is placed on shelves to ripen for periods ranging from
15 days to a year or two.
Semantic cohesion and rhetorical cohesion
The writer’s train of thought is conveyed to the reader with appropriate
logical cohesive discourse markers.
Logical markers (also called “discourse markers”), on the other hand,
do not have lexical meaning but act as logical signals, that is, they signal
the rhetorical intention of the writer, his train of thought.
The logical markers which appear in the 2nd part of the paper signal the
following rhetorical intentions of the writer:
contrast
addition
alternation
back reference
forward reference
duration
exemplification
reason
result
progression
succession
generalisation
The logical markers of the 2nd part of the paper have been highlighted in
grey and the type of each of them has been identified in brackets.
Apart from logical cohesion the text is also characterized by semantic
cohesion. Semantic cohesion is achieved by using appropriate synonyms,
cover terms and specific terms which carry lexical meaning within the
same discipline register, i.e. ‘starter culture’, ‘lactic acid bacteria’,
‘fermentation’ etc. Students need to master the register of their discipline.
A good dictionary of their field terminology is deemed essential. They
25
should also read relevant published papers extensively, to familiarize
themselves with good examples of scientific discourse in their field.
Extensive use of visuals to provide data
The writer offers the readers a wealth of relevant scientific data in visual
form with appropriate use of tables, graphs and diagrams in the 2 nd part of
the paper. He has also used a couple of relevant photographs.
More specifically, the writer has used a flow-chart to show the process of
cheese making (Figure 2) and the biochemical changes in cheese making
(Figure 4) in brief. To do the latter in detail, he has used a very
sophisticated flow-chart (Figure 5).
Apart from flow-charts, tables have been used (Table 1, Table 2) and also
graphs (Figure 7) and bar graphs (Figure 8).
(We will examine the rest of the paper in my next posts.)
26