ABSTRACT
This work involved the investigation of the effect of different substrates (Andropogon gayanus, Pennisetum purpureum and Panicum maximum) on the yield, proximate composition and mineral composition of Pleurotus ostreatus var florida. The highest gross yield fruit-bodies was obtained from the substrate Andropogon gayanus(1059.84%), followed by Panicum maximum (568.4%), while the least was found in Pennisetum purpureum (202%). Similarly the fruit-bodies of substrates Andropogon gayanus weighed more than those from other substrates for both fresh and dry weight. Based on the proximate composition, carbohydrate was found to be highest (72.03±1.52) in mushrooms harvested from P. purpureum, followed by P. maximum (71.39±0.83) while fruit bodies harvested from A. gayanus gave the lowest (70.69±1.72). Ether extract in all the fruit bodies was the lowest among all the parameters studied at (0.38±0.03) in P. purpureum(0.30±0.02) in A. gayanus and (0.20±0.02) in P. maximum. Based on the mineral composition, Result showed that all the fruit-bodies obtained from A. gayanus substrate contained appreciable amount of Calcium (1.60±0.20), Potassium (2.35±0.05), Magnesium (31.26±0.035) and Sodium (2.20±0.20). Similarly, fruit bodies obtained from P. maximum had the highest (75.74±0.035) concentration of Phosphorus while there was no significant difference in the amount of sulphur contained in fruit-bodies harvested in all the substrates at p≤0.05. However, the lowest (0.70±0.10) Calcium composition was recorded in mushrooms harvested from P. purpureum. Likewise P. maximum gave the lowest Sodium (1.70±0.10) and free Nitrogen (1.90±0.10) contents. The result of the investigations was discussed in line with the best substrates for the maximum production of Pleurotus ostreatus fruit-bodies with better qualities. The investigation concluded that growing Pleurotus ostreatus on A. gayanus straw produced the highest fruit-bodies among other substrates which will aid in the wide production of mushroom for market values. Generally, Pleurotus ostreatus contain valuable nutritional properties.
TABLE
OF CONTENT
Title
page i
Declaration ii
Certification
iii
Dedication iv
Acknowledgement v
Table
of content vi
List
of Tables ix
Abstract x
CHAPTER
ONE
1.0 Introduction 1
1.1 Taxonomic classification P. ostreatus(Oyster mushroom) 3
1.2 Cultivation of Mushrom 3
1.3 Edible Mushroom 4
1.4
Economics importance of Mushroom 5
1.6
Justification of Study 6
1.7 Aims and objectives 8
CHAPTER
TWO
2.0 Literature review 9
2.1 Mushroom Cultivation 9
2.2
Nutritional Compositions of Cultivated Mushrooms 14
CHAPTER THREE
3.0
Materials and Methods 16
3.1
Sources of starter culture (spawn) 16
3.2
Location of study 16
3.3
Experimental design 16
3.4
Spawn Multiplication 17
3.5
Substrate preparation 17
3.6
Preparation of cropping room 18
3.7
Inoculation of substrates 18
3.8 Determination of yield and biological
efficiency 19
3.9 Sample Preparation 19
3.10 Proximate Analysis 19
3.10.1 Determination of crude protein 19
3.10.2 Determination of moisture content 20
3.10.3 Determination of the ash content of
fruit bodies 20
3.10.4 Determination of crude (dietary fibre) 20
3.10.5 Determination of the carbohydrate
content of the sample 21
3.10.6 Determination of dry matter (DM) 22
3.10.7 Determination of fats and oils 22
3.12 Determination of mineral content of the
dry samples of the Mushroom 18
3.13 Statistical Analysis 19
CHAPTER
FOUR
4.0 Results and Discussion 28
4.1 Results 28
4.2 Discussions 31
CHAPTER
FIVE
5.0 Conclusion and Recommendations 35
5.1 Conclusion 35
5.2 Recommendations 35
REFERENCES 37
APPENDIX 44
LIST OF TABLES
Tables 1: Effect of straw substrates on
the yield (g) and Biological efficiency (%) of Pleurotusostreatusfruit-bodies
Table 2: Effect of straw substrates on the
proximate (%) composition of P. ostreatus fruit-bodies.
Table 3: Effect of straw substrates on the
minerals (mg/100g) composition of P. ostreatus fruit-bodies.
CHAPTER ONE
1.0 INTRODUCTION
Mushrooms are macro-fungi with distinctive
fruit-bodies, which can be either epigeous or hypogenous and large enough to be
seen with un-aided eyes and be picked by hand (Chang and Miles 2004). They are
heterotrophic, because of the absence of chlorophyll, but take up nutrients
from outer sources (Oei, 2003). Mushrooms reproduce by spores, under favourable
conditions. The spores germinate into hyphae collectively called mycelia.
Germinated hyphae form primary mycelia and then secondary hyphae, through
plasmogamy. (Oei, 2003). They accumulate nutrients from the substrate and
colonize it and when stimulated by variable environmental conditions, the
mycelia colony forms pin-heads (young fruit-bodies). The pin-heads ultimately
grow to mature fruit-bodies and finally differentiate into cap and stipe called
mushroom (Oei, 2004).
They are usually found in pastures, meadows,
and wood-lands. Some are commercially
raised in caves, indoors on shelves; filled with partly decaying animal and
plant materials and in green houses where the average outside temperature is
cool (Cajuguiran et al., 2010). Some
mushrooms are capable of `producing underground tuber-like structure called
sclerotia. The sclerotia are usually harvested from decaying logs or other
substrates where the mushroom is growing. The dark brown exterior is peeled off
and the white compact mycelia tissue is used for food (Oso, 1977; Isikhuemhen
and Le Bauer, 2004).
Mushroom is cultivated worldwide, especially in southeast
Asia, India, Europe and Africa. They can be cultivated under both temperate and
tropical climatic conditions and harvested all over the year. The oyster
mushroom (Pleurotus spp) are in third
place after the white button and shiitake among the world mushroom production
(Gyorfi et al., 2007).
Oyster mushrooms are the easiest and least
expensive commercial mushrooms to grow because they are well known for the conversion
of crop residues to food protein .They are also rich source of proteins,
minerals and vitamins (Caglarirmak, 2007).
Mushroom
cultivation represents the only current economically viable biotechnology
process for the conversion of waste plant residues fromforests and agriculture
(Wood and Smith, 1987). Culture of Oyster mushroom is becoming popular
throughout the world because of abilities to grow at a wide range of
temperatures and to utilize various lignocelluloses(Ali et al., 2007a;
Sanchez, 2010b).
Pleurotus species have extensive enzyme systems capable of utilizing complex
organic compounds that occur as agricultural wastes and industrial by-products.
These
mushrooms are also found to be one of the most efficient lignocelluloses solid
state decomposing types of white rot fungi (Baysal et al., 2003).
1.1 Taxonomic
classification P. ostreatus (Oyster
mushroom)
The classification of the species within the
genus Pleurotus is difficult due to
high phenotype variability across wide geographic ranges, geographic overlap of
species and ongoing evolution and speciation. (Kong, 2004).
Pleurotus ostreatus is thus classified as follows:
Kingdom Fungi
Phylum Basidiomycota
Class Agaricomycetes
Order Agaricales
Family Pleurotaceae
Genus Pleurotus
Species ostreatusvar florida(Eger)
1.2 Cultivation of Mushroom
All mushroom growing techniques require the
correct combination of humidity, temperature, substrate (growth medium) and
inoculums (spawn or starter culture). Wild harvest, outdoor log inoculation and
indoor trays, all provide these elements. (Wikipedia, 2014). Pleurotus mushrooms can be cultivated on
logs of some tree species (Molena, 1986; Chang & Miles, 2004). However, the
traditional procedure for this mushroom's cultivation is to use pasteurized
compost steam (Molena, 1986; Obodai et
al., 2003). On the other hand, these mushrooms exhibit great versatility
and fast colonization rates, so several alternative cultivation techniques have
been proposed. Some propose using either hot or chemical treatments to
disinfect substrates without using composting, whereas others suggest using
compost but without a pasteurization process (Hernández et al., 2003; Contreras et
al., 2004; Mandeel et al., 2005).
These procedures are not sufficient to eliminate all of the microorganisms
present in a substrate; nevertheless, they can reduce contaminants to a level
that permits mushroom mycelia to colonize all of a substrate competitively.
There are three factors to be considered in
mushroom cultivation. These are:
(1)
spawn, which should maintain the strain characteristics and is propagated by
subculture.
(2) The substrate, which should be used according
to the mushroom species and (3) Appropriate environment both for vegetative and
reproductive growth (Cho, 2004).
1.3 Edible Mushroom
The constituents of an
edible fungus are not necessarily a good guide to nutritional value (Breene,
1990). The digestibility of different components varies, while analytical
methods are not always reliably used in testing (Crisan and Sands, 1978; Lau,
1982). The use of different techniques for analysing nutritional value also
limits a comparison of results from different studies. Estimates of (usable)
protein content should exclude Chitin present in fungal cell walls, for
example. This is not always observed in studies.
The popularity of mushrooms is still based
not on the nutrients that they contain but mostly on their exotic taste and
their culinary properties, whether eaten alone or in combination with other
foods (Quimio, 2004). They are thus valuable health foods which are low in
calories, high in vegetable proteins, zinc, chitin, fiber, vitamins and
minerals (Alam and Raza, 2001). They are usually eaten raw or cooked or
garnished to a meal. Dietary mushrooms are good sources of B vitamins such as
riboflavin, niacin, pantothenic acid and the essential minerals, selenium,
copper, potassium, fat, carbohydrates and their calorie content are low (Alam
and Raza, 2001). Mushroom also contains all the essential amino acids as well
as the commonly occurring non-essential amino acids and amides. Lysine, which
is low in most cereals, is the most important amino acid in mushrooms. Mushroom
protein is indeed as valuable additive to the human diet (Quimio, 2004).
1.4 Economic importance of Mushroom
Mushroom
are used extensively in many cuisines (notably Chinese, Korean, European and
Japanese). They are the “meat” of vegetable world. Oyster mushroom are popular
for cooking,torn up instead of sliced, especially in stir fry or sauce, because
they are consistently thin and so will cook more even than uncut mushroom of
other types (Haas and James, 2009).
1.5 Medicinal uses of
Mushrooms
There are various chemical compounds found in
mushrooms that reportedly have medicinal uses and benefits.The lipid component
of Agaricus was found to contain a compound with anti-tumor activity which was
later identified as ergosterol (Takaku et al., 2001). Similarly the lipid
fraction of Grifola exhibits antioxidant activity and inhibits enzymes that
cause many chronic diseases including cancer (Inoue et al., 2002). The mushroom
constituents not only inhibit progression of the disease by exerting direct
cytotoxicity against tumor cells (Chang, 1996) but also up regulate other
non-immune suppressing mechanisms. These constituents are beneficial even in
some established tumours (Bender et al., 2003) and isolates from mushroom cells
have cytostatic compounds that induce apoptosis in leukamia cells. The
chemicals produced by species of Ganoderma have antibacterial properties
(Smania et al., 1999) and have been shown to inhibit the growth of bacteria
such as Staphylococcus (Mothana et al., 2000). Steroids isolated from them are
active against numerous gram negative and gram positive microorganisms
(Kuznetsov et al., 2005).
1.6 Justification of Study
Mushroom cultivation represents the only current
economically viable biotechnological process for the conversion of waste plant
residues from manufacturing industries, forests and agricultural farmlands into
protein rich food (mushrooms) and other valuable intermediate or finished
products (Wood and Smith, 1987). There is enormous waste in the agro-industry;
using 25% of the yearly volume of burned cereal straws in the world could
result in a mushroom yield of 317 million metric tons (317 billion kg) of fresh
mushrooms per year (Chang and Miles, 2004). Considering the yearly available
world waste in agriculture (500 billion kg), we could easily grow mushroom of
about 360 billion kg/year, all containing 4% protein from fresh mushrooms
(Poppe, 2004).
Mushrooms cultivation can thus be considered
as the most economic method of converting lignocellulosic agricultural wastes
to consumable, protein rich biomass (Ali et
al., 2007). Conversion of lignocellulose into food and feed rich in protein
by fungi offers an alternative means for developing unconventional sources of
proteins as food/feed (Mane et al.,
2007).
Hence,
the use of different agricultural wastes such as banana leaves, Alam grass (Imperata cylindrica) straws, baggasse,
husk, pods, pulp, waste paper, corn cobs etc as substrates is a development, welcome.
Considering the enormous potentials of
mushrooms, more works researches are required for its cultivation so as to know
substrates (Agricultural wastes) that support the growth and yields of
mushrooms.
Finally, since the price of meat, fish and
other protein sources are on constant increase, there is the need to embark on
researches that would increase the commercial mushroom production, consumption
and exportation to other neighbouring countries for income generation
1.7 Aims and Objective
The aims and objective of this research is
to:
1 Determine the effect of straw substrates on
the yield(g) and biological efficiency(%) of Pleurotus ostreatus fruit-bodies.
2 Determine the straw substrate on the
proximate(%) composition of Pleurotus
ostreatus fruit-bodies.
3 Determine the effect of substrates on the
minerals(mg/100g) of Pleurotus ostreatus
fruit-bodies
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