This document discusses the classification of dietary fiber. It outlines several classification systems used to categorize fiber components based on their role in plants, polysaccharide type, solubility, site of digestion, and digestion products. The most widely accepted system classifies fiber as water-insoluble/less fermentable (cellulose, hemicellulose, lignin) or water-soluble/well fermentable (pectin, gums, mucilages). Cellulose, hemicellulose, lignin and their properties are described. Pectin is highly water-soluble and fermented by colonic bacteria. Gums and mucilages form gels and bind water. Banana fibers are a potential source

1. BY Dr. SREEREMYA.S
FACULTY OF BIOLOGY

2.  Classification of dietary fibre
 Some researchers suggested several different classification systems to mainly classify the
components of dietary fibre: based on their role in the plant, based on the particular type
of polysaccharide, based on their stimulated gastrointestinal solubility, based on site of
digestion and based on products of the digestion and physiological classification.
However, none is entirely satisfactory, as the limits cannot be absolutely delineated. The
most vastly accepted classification for dietary fibre has been to differentiate dietary
components on their solubility in the buffer at a defined pH, and/or their ferment ability
in an in vitro system using an aqueous enzyme solution representative of human
alimentary enzymes. Thus most appropriately dietary fibre is mainly classified into two
categories such as the water- insoluble/less fermented fibres: cellulose, hemicellulose,
lignin and the water-soluble/well fermented fibres: pectin, gums and mucilages (Burkett,
1975). Cellulose it is the main cell wall component in plants, a nun branched linear chain
of several thousand glucose units with β-1, 4 glucosidic linkages. Cellulose’s mechanical
strength, resistance to the biological degradation, low aqueous solubility and resistance
to acid hydrolysis result from hydrogen bonding within the microfibrils (Byrne, 1997).

3.  Cellulose is not digested to any extent by the enzymes of
the human gastrointestinal system (Brennan et al.,
2008).Hemicellulose these are cell wall polysaccharides
solubilized by aqueous alkali after removal of water soluble
and pectic polysaccharides (Camire et al., 1991). They
comprises backbones of glucose units with β-1, 4 glucosidic
linkages, but differ from cellulose in that they are smaller in
size, contain variety of sugars and are generally branched .
They encompass mostly xylose and some galactose,
mannose, arabinose and other sugars (Camire et al.,
1997).Lignin it is not the polysaccharide but a complex
random polymer comprising about 40 oxygenated phenyl
propane units including coniferyl, sinapyl and p-coumary l
alcohols that have undergone a complex dehydrogenated
polymer ization (Caprez et al., 1986)..

4.  Lignin mainly vary in molecular weight and methoxyl
content. Due to the strong intramolecular bonding,
which includes carbon to carbon linkages, lignin is
very inert. Lignin mainly demonstrates greater
resistance than any other naturally occurring polymer.
Pectin: Pectic substances are a ramified group of
polysaccharides in which D-galacturonic acid is a
principal constituent. They are structural components
of plant cell walls and also act as intercellular
cementing substances. Pectin is extremely water-
soluble and is almost completely metabolized by
colonic bacteria (Chan, 1988).

5.  Due to their gelling behavior, these soluble polysaccharides may mainly
decrease the rate of gastric emptying and influence small intestinal
transit time. This vividly explains their hypoglycemic properties .Gums
and mucilages-These are the types of plant fibers that are not cell wall
constituents but are formed in specialized secretory plant cells .These
are reported to be much highly branched polysaccharides that form
gels, bind water and other organic material. Gums are sticky exudations
formed in the response to trauma (i.e.gumarabic). They mainly consist
of guar gum and gumarabic. Guar gum is the galactomannan isolated
from the seed of Cyamopsis tetragonolobus (guar). Partial enzymatic
hydrolysis results in the product that can be availed as a soluble dietary
fibre. The physiological effects of this fibre source comply with what
might be expected from the soluble fibre. Gumarabic is exudated from
the acacia tree, is a complex arabinogalactan polysaccharide in
admixture with a glyco-protein

6.  Banana has long been considered a food, fruit and fodder crop.
In addition to this, now a day, it is also gaining significance as a
source of fibers. India is the largest producer of banana in the
world with an estimated annual output of 13.6 million tons, of
which 80% is generated from six states, namely, Tamilnadu,
Maharashtra, Karnataka, Kerala Andhra Pradesh and Gujarat.
Annually about 1.6 million tons of dry banana fibres can be
produced from the outer sheath of pseudo stem (Chevance et al.,
2000). With the aggrandizing demand for banana in both the
Indian and International markets, the acreage and production
are expected to aggrandize in the coming years, thus generating
more of the pseudostem biomass waste. Being a rich source of
natural fibres, the pseudostem can be much profitably utilized
for numerous applications and preparation of various products.

7.  In Brazil, which is the fourth largest producer in the world at over 7.1
million tones, produced by conventional cultivation systems. One
aspect of the Brazilian development, majorly due to the country’s
agricultural trait, is related to the development of its agro-industrial
sectors. Like the sugarcane and citrus production ramifies, other
sectors of socio-economic importance have been explored with a
comprehensive view in order to bring greater added value to
agricultural products, avoid food waste, aggrandize farmers’ income,
and develop alternative and nutritious food raw material .In the green
stage, banana stands out for having a high starch/resistant starch
content, deserving the industrial interest for developing new products
(Cho et al., 1999). Moreover, it has a broad range of vitamins and
minerals present in both pulps and peels. The green banana mass, a
material obtained by grinding fresh bananas, dates from the mid-90s
and has been studied for food production of green banana pulp mass
and green banana peel mass. And since it is high-starch-content
biomass, it has gained ground in the development of the products such
as the breads, gnocchi, pates, mayonnaise, pasta, and others.

8.  Journal of Midwifery, Women's Health and Nutrition,
Nutritional Aspect of Banana and Banana Fibres,
Dr.S.Sreeremya , 2019.Vol 1(2):1-10.