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CALORIMETRY AND FOOD SCIENCE

Food science is a domain of life science. The intensity of changes during the freezing storage of frozen foods depends on several factors. The applications of low temperature are very common during the canning of fresh or processed foods. Many authors consider that changes in products are smallest if they are stored at low temperatures, which is also a kind of canning process.

Very often, before freezing, in the food industry, fresh fruits are blanched. Blanching is a process of short-term heat treatment for the purpose of denaturing enzymes that affect the color or in order to increase the softness of a product.

Studies conducted on the effect of freezing on the composition and properties of meat have shown that the freezing process (temperature, freezing rate), storage, and thawing conditions of previously frozen different food products affect their thermal properties. It is important to note at this point that water plays a crucial role in changing food properties during freezing.

Food products are multi-phase and multi-component metastable systems where several processes can occur simultaneously during the preparation process and the shelf life.

Applications of thermal analysis and calorimetry (TAC) to food products deal with many investigation targets spanning from the characterization of the systems at a molecular and supramolecular level to the description of the microbial metabolism.

Changes in foods during freezing and thawing can be rapidly determined
by differential scanning calorimetry (DSC). A scanning calorimeter is a type of calorimeter.

With DSC, there are typically two pans, one sample pan, and one reference pan. The sample pan contains the sample while the reference pan remains empty. Each pan is heated separately at a specific rate, and this rate is maintained throughout the experiment.

A computer system ensures that each pan heats up at the same rate, however, so that a measurement can be taken. The heater underneath the sample pan has to work harder than the empty reference pan, meaning it puts out more heat. The difference in the amount of heat put out is how a measurement is made.

Differential scanning calorimetry belongs to a group of thermal analyses based on measuring the heat flux difference between the sample and the reference substance, that is, the energy required to equalize the temperature between the sample and the
reference substance, during heating or cooling of the sample, under controlled conditions.

DSC is a thermal analysis technique to measure the temperature and heat flows associated with phase transitions in materials, as a function of time and temperature. DSC is particularly suitable for the analysis of food systems because they are often subject to heating or cooling during processing.

The calorimetric information from DSC can be directly used to understand the thermal transitions that the food system may undergo during processing or storage. DSC applications are used from troubleshooting up to new product developments.

Typical food sample and their application by DSC by Patricia Heussen (2011), Practical food application of Differential Scanning Calorimeter. https://www.perkinelmer.com/CMSResources/Images/44-129725APP_DSC_Food_Applications.pdf

In conclusion, DSC is used to study fat phase transitions and melting range. It is one technique used to explain the physical and textural properties of fats in bulk and final products.

FUNDAMENTAL AND DERIVED UNITS 1

FUNDAMENTAL AND DERIVED UNITS :
In mechanics, there are three basic units or fundamental units and they are length, time and mass. Derived units are then represented where dimensional representatives are necessary.

FUNDAMENTAL UNITS
Fundamental unit are the basic foundational units in science and there are a few of this fundamental physical quantities.

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DERIVED UNITS
This simply is the combination of the fundalmental unit. From the combination of one of the same or two or more fundalmental units we can obtain other useful units. Such units are called derived units.

Learn math in 60 seconds

The unit of volume is obtained by multiplying three lengths,  which is called cubic meters. Density is the ratio of mass and volume. Then the S.I. unit of density is called kilogram per cubic meter.

Speed is the ratio of distance and time, so therefore the unit is  called meter per seconds. Other derived units are listed below:

Examples:

Note that in dimensions,

i. Mass is represented by letter “M”

ii. Time is represented by letter “T”

iii. Length or distance is represented by letter “L”

Simple Calculations of some Dimensions

These are the three major symbols used in dimension. So let’s see how it is use in dimensioning;

FORCE: This is the product of mass and acceleration
F = ma
Where: m = mass = M
a = acceleration = L/T² ..…………… (i)

So the dimension for Force = M L/T²

MOMENTUM: This is the product of mass and velocity
P = MV
Where: m = mass = M
V = Velocity = L/T  ………………………. (ii)

So the dimension for Momentum is = ML/T

PRESSURE: This is force per unit area

Where: F = force =  as in (i) above
A = area = L²   ….……………. (iii)

So the dimension for Pressure is = F / A

= M L/T² * 1/ L²   = M/ T² L

VOLUME: is the quantity of three-dimensional space enclosed by some closed boundary.

V = L³………………………. (iv)

DENSITY: This is mass per unit volume

Where: M = mass = M
V = volume = L³………………. (v)

The dimension for Density is = M/ L³

VELOCITY: This is distance per unit time

Where: D = Distance = L
T = Time = T …………………………. (vi)

The dimension for velocity is = L/T

ACCELERATION: This is velocity per unit time

Where: V = velocity = as in (vi) above
T = time = T …………………………… (vii)

The dimension for acceleration is = V/T = L/T * 1/T

= L/ T²

IMPULSE: This is the product of force and time

Where: F = force =  as in (i) above
T = time = T ……..………… (viii)

The dimension for impulse is = F * T

= M L/T² * T

= ML/T

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24 Hours of Life: How to live on 24 hours a day

We’ve all heard the saying 24 hours in a day, but how many of us actually live by it? I mean, we go to bed and there’s that pesky fact that you need 8 or 9 hours of sleep. Then there are errands, meals, time spent with family and friends, where does it all go?

You’re left wondering why didn’t I get to work on that book I wanted to write? Or maybe you look at a wall covered with dust, and say to yourself: “self, when am I going to find the time to clean this house?”

Here are three rules to help you live on a 24 hours a day.

Rule 1: Rule your Hour.

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24 hours is enough time to accomplish almost anything. To live on 24 hours a day you have to rule your hours. You can’t get more time, but you can spend your time better.

Have the right attitude toward time! It’s limited, so don’t waste it with negative thinking and unproductive activities.

Make choices that will help make the most of your life, both now and in the future. The secret is to learn how to manage your time effectively. If you’re having trouble doing this, here are some tips:

Don’t overbook yourself; leave room for spontaneity,

Plan ahead for major tasks like shopping or appointments,

Use a calendar or planner to keep track of events and deadlines,

Make lists of things that need doing; such as phone calls or errands.  So they’re easier to remember than if they’re just floating around your head all day long. this is where an electronic calendar comes in handy.

Rule 2: Do the day’s work.

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The best way to live on 24 hours a day is to do the day’s work. The day’s work consists of all that can be done in 24 hours. There are 24 hours of daylight; there are 24 hours of darkness.

But the actual working time varies very much according to the individual. Some people can do more than others in a given time, just as some men can run faster than others, or jump higher, or throw farther than others.

To live on 24 hours a day you have to do the day’s work. You can not get time by making more time, but by using the time you have. The secret of getting ahead is getting started.

You are probably thinking of some excuse why you cannot do this or cannot start now. But if you really want to get ahead, use your imagination and find ways to start.

When you choose your goal, set a deadline for achieving it. If there is no deadline, then there will be no urgency to take action!

Another important point to note: You need to say “NO” to people who do not support your goal and “YES” for those who do!

Rule 3: Be Positive.

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To live on 24 hours a day you have to be positive. You have to see the bright side of things, and that is not always easy.

I try to think positively about all the things that could happen in my life. I try to think positively about all the things that are happening in my life.

I think it’s important that we do this because it helps us look at our lives in a different way. Instead of thinking about all the things that go wrong and all the things we’re unhappy with, we start thinking about all the good things instead!

If you want to live on 24 hours a day, then you need to stop wasting time being unhappy and start doing something about it!

Thanks for watching and see you in the next video.