Nutrients and food additives in the food technology

Food additives

1. UNIT 2
NUTRIENTS & FOOD ADDITIVES
Nutritional Physiology
Digestion, absorption, and utilization of major nutrients
Digestion, absorption, and utilization of minor nutrients..
JEROLINE MARY
AP/FOOD
DSCET

2. Nutrition physiology deals with how body extracts the nutrients from food, how we obtain
the needed energy, how we utilize nutrients and how all this is related to health and disease.
Nutrition physiology concerned with different types of food and their effects on the
metabolism
Digestion is the process of mechanically and enzymatically breaking down food into
substances for absorption into the bloodstream. The food contains 3 macronutrients that
require digestion before they can be absorbed: fats, carbohydrates, and proteins.
Nutrient absorption - This comes after the breakdown of carbohydrates, proteins, fats,
vitamins, and minerals, which are essential for energy production, growth, and cellular
maintenance. Egestion of waste and toxins - The process eliminates indigestible
components and harmful substances from the body
The digestion (breaking down into smaller pieces) of these nutrients in the alimentary tract
and the subsequent absorption (entry into the bloodstream) of the digestive end products
make it possible for tissues and cells to transform the potential chemical energy of food into
useful work.
Nutritional Physiology

3. Carb digestion

4. Protein digestion

5. Lipid digestion

6. CARBOHYDRATES PROTEINS LIPIDS
The digestion of carbohydrates by
salivary amylase begins in the mouth.
Food remains too short in the mouth so
little digestion takes place
1.
As saliva contains no proteolytic
enzymes, proteins are not
digested in the mouth and
during the process of chewing
the surface area of the food
mass is elaborated in the mouth.
1. Lingual lipase secreted by
lingual serous glands on the
dorsal surface of tongue, can
continue its activity at low pH
of stomach, where about 30%
of triglycerols may be digested
1.
2. The chewed food called bolus enters the
stomach. The digestion by salivary amylase
continues in the stomach for 10 - 15
minutes until the food gets mixed in the
gastric juice
2.. Gastric juice contains 0.45 % HCl
and proteolytic enzyme pepsin.
Once it is mixed with food pH fall to
2 to 3 which is optimum for
digestion of proteins by pepsin.
2. Fats are hydrolyzed primarily in
the upper small intestine by the
action of pancreatic lipase. Some
digestion of triglycerides may also
take place in the stomach.
3. The semisolid mass of food called the
chyme leaves the stomach within 2 - 4
hours after food is taken. If chyme is more
solid it takes longer time to leave the
stomach.
3. Pepsin is present as inactive
pepsinogen. Pepsinogen is
converted into active pepsin by the
HCl present in gastric juice
3. As chyme enters duodenum,
presence of fat stimulates release of
hormone Enterogastrone. This
hormone and regulates flow of
chyme to correspond to pancreatic
secretions.
Digestion, absorption, and utilization of major nutrients

7. CARBOHYDRATES PROTEINS LIPIDS
4. The chyme enters the small
intestine(SI) for further breakdown. SI
has duodenum, illeum, jejunum
4. By the time dietary proteins leave
the stomach, the pepsin digests 10-
20% of protein by breaking the
peptides into various lengths of
polypeptides and also releasing
individual amino acids
4. The pancreatic lipase acts on the
finely emulsified lipid droplets formed
by mechanical agitation in the gut, in
the presence of the products of lingual
lipase activity, bile salts, colipase
5. The pancreatic duct opens into the
duodenum & jejunum. The pancreatic
juice further breaks the carbohydrates.
Polysaccharides break down into mono
& di saccharides
5. Pancreas and SI produce digestive
proenzymes namely trypsinogen and
chymotrypsinogen which are released
into intestine. As soon as chyme reaches
duodenum, enzyme enterokinase
transforms the inactive trypsinogen into
active trypsin
5. Triacylglycerols are hydrolyzed
stepwise by pancreatic lipase, that is,
one of the end fatty acids is removed at
a time, yield in turn a diacylglycerol,
and then a monoacyl glycerol,
6. The small intestine empties into large
intestine. A very small portion of
indigestible carbohydrates will be
present in the large intestine.
6. These activated proteases trypsin,
chymotrypsin and carboxypeptidases
continue to break down the protein until
simple peptides and amino acids are
released
6. Triacylglycerols is broken down to
glycerol and fatty acids. Cholesterol
esters are hydrolyzed by cholesterol
ester hydrolase (or) cholesterol esterase
present in the pancreatic secretions to
form cholesterol and fatty acids.
Digestion, absorption, and utilization of major nutrients

8. CARBOHYDRATES PROTEINS LIPIDS
7. The large intestine is connected to a
anus, where the faeces gets eliminated
7. Transport of nutrients across the
intestinal mucosa and cell membranes
takes place by “active transport”
7. Most of the absorption of fat
occurs from the jejunum.
8. Most of the absorption of
carbohydrates takes place in the small
intestine. SI has microvilli which has lot
of absorptive cells. SI uses 4 types of
absorption: active, passive, facilitated &
endocytosis
8. The amino acids associate with the
carrier and Na ion in the microvillus and
the complex, travels to the micro side of
the membrane where it dissociates,
releasing the amino acid and Na ion into
the cytoplasm. The carrier returns back
and functions repeatedly. The Na ion is
then actively transported out of the cells
8. Absorbed lysophospholipids &
cholesterol are reacylated with fatty acids
to regenerate phospholipids and
cholesterol esters. These cholesterol
esters, phospholipids, triacylglycerols,
cholesterol and fat-soluble Vitamins
generate chylomicrons, that is collected
and passed to the systemic blood
9. Carbohydrates are body's main fuel
source. During digestion, carbs are
broken down into simple sugars.
They're then absorbed into the
bloodstream, where they're known as
blood sugar. From there, glucose enters
the body's cells with the help of insulin
9. Protein helps repair and build
body's tissues. It drives metabolic
reactions, maintains pH and fluid
balance, and keeps immune system
strong. It also transports and stores
nutrients and act as energy source.
Protein is crucial to good health
9. After absorption from the
alimentary canal and their modification
lipids must be carried in the blood
either to storage sites or to the
muscles and other tissues, where they
serve as source of energy. From the
storage sites,they must be taken to the
active tissues
Digestion, absorption, and utilization of major nutrients

9. VITAMINS MINERALS
They do not require digestion. They are either water
soluble or fat soluble, hence no enzyme is required to
digest vitamins. They are absorbed directly from the
digestive tract, transported by blood to the cells, and the
cells absorb and use them whenever they need.
1.
Most minerals are absorbed into the bloodstream in
the upper part of the small intestine. They then pass
to the liver and are (like other nutrients) distributed
throughout the body.
1.
2. Absorption of Water-soluble Vitamins
Most water soluble vitamins are available for intestinal
absorption from two sources: 1) the diet, and 2) synthesis by
microbes in the large intestine. These dual-origin vitamins
include biotin, folic acid, pantothenic acid, riboflavin and
thiamin. Water soluble vitamins of dietary origin are absorbed
predominantly in the small intestine, whereas those
synthesized by microbes in the large intestine are absorbed
there. For most of these vitamins, specific carrier-mediated
transport systems have been identified that allow uptake from
the intestine into the enterocyte.
2. Mineral absorption is normally proportional to dietary
intake, with two important distinctions—the absorption
of iron and calcium, both of which can be regulated
according to the needs of the body. Calcium absorption
is related to the amount of specific binding protein
within the enterocyte. The concentration of the calcium
binding protein, which regulates calcium uptake from
the gut, is secondary to vitamin D levels.
Digestion, absorption, and utilization of minor nutrients

10. VITAMINS MINERALS
3. Absorption of Fat-soluble Vitamins
The fat soluble vitamins A, D, E and K are absorbed from the
intestinal lumen using the same mechanisms used for
absorption of other lipids. In short, they are incorporated into
mixed micelles with other lipids and bile acids in the lumen of
the small intestine and enter the enterocyte largely by
diffusion. Within the enterocytge, they are incorporated into
chylomicrons and exported via exocytosis into lymph.
3. Iron absorption occurs in the duodenum and proximal
jejunum. Following digestion, iron is in two forms. The
first is haem iron bound to hemoglobin and myoglobin.
The second form is free ionized iron in the ferrous and
ferric state. Hem iron is absorbed by binding to a
probable hem receptor, whereas free iron is likely to be
absorbed by a specific carrier protein. Free iron is
cytotoxic, so it is bound inside enterocytes to the large
storage protein, apoferritin, or bound to transferrin for
export to the bloodstream.
Digestion, absorption, and utilization of minor nutrients

11. ALL THE BEST