EFFECT OF STORAGE PERIOD ON THE NUTRITIONAL AND MINERAL CONTENTS OF PLEUROTUS TUBER REGIUM
ABSTRACT
This research work was carried out to evaluate the effect of storage period on the nutritional (proximate) and mineral content of pleurotus tuber regium (Osu). Pleurotus tuber regium was sourced, sorted, washed, split into portions, dried (72hrs), ground , packaged and stored for the period of two and three weeks. The proximate composition and mineral content evaluation was carried out on the stored and fresh sample. Moisture content ranges from 41.24-65.25%, Ash content ranges from 5.50-7.25%, Crude fibre ranges from 1.00-2.80%, Crude protein ranges from 7.20-10.00%, Fat content ranges from 3.78-6.20%, while the carbohydrate ranges from 10.44-36.25%. Also mineral content was determined, the manganese ranges from 3.13-4.10%, copper 74.11-84.25%, sodium ranges from 188.00-192.60%, Calcium ranges from 33.00-37.20%, Magnesium ranges from 22.00-26.35%, Nickel ranges from 21.00-26.35%, while the Iron ranges from 111.00-122.00%. In conclusion, the result shows reduction in the moisture, protein, and fact, while the ash, fibre and carbohydrate increased after storage. The Fe, Ca, Mg, Na, Ni and Cu content increased, while the Mn content reduced after storage. Stored pleurotus tuber regium has a rich source of mineral compared to the fresh sample.
TABLE OF CONTENTS
CHAPTER ONE
1.0    INTRODUCTION                              
1.1    Background of the Study                              
1.2    Statement of the problem                              
1.3    Aims                                   
1.4    Objective of the Study                          
CHAPTER TWO
2.0    LITERATURE REVIEW                    
2.1    History and Distribution of Pleurotus Tuber regium             
2.2    Oyster Mushroom (Fungus)                    
2.3    Taxonomy                                        
2.4    Ecology                              
2.5    Growth of Mushroom                   
2.5.1    Substrates                               
2.5.2    Environment                   
2.5.3    Cultivation                                   
2.7    Nutritive Value                          
2.8    Medicinal Uses                                
2.9    Pest and Diseases                                 
2.10    Preservation of Pleurotus Tuber Regium                  
CHAPTER THREE
3.2    MATERIALS AND METHOD               
3.1    Equipment and Glasswares                      
3.1.1    Reagent/Chemicals                              
3.2    Methods                              
3.2.1    Materials Collection of Sample                        
3.2.2    Sample Preparation/Processing                        
3.2.3    Proximate Composition Determination                   
3.2.3.1 Moisture Content Determination                     
3.2.3.2    Ash Content Determination                      
3.2.3.3    Determination of Crude Fibre                       
3.2.3.4    Crude Protein Content Determination                
3.2.3.5    Total Lipids Determination                      
3.2.3.6    Carbohydrate Determination                
3.2.4    Determination of Mineral Composition of Pleurotus Tuber Regium       
3.2.4.1    Iron Determination                           
3.2.4.2    Manganese Determination          
3.2.4.3    Calcium Determination                            
3.2.4.4    Magnesium Determination                  
3.2.4.5    Nickel Determination                       
3.2.4.6    Copper Determination                        
3.2.4.7    Sodium Determination                         
CHAPTER FOUR
4.0    RESULT AND CONCLUSION                      
4.1    Result                                 
4.2    Discussions                               
 CHAPTER FIVE
5.0    CONCLUSION AND RECOMMENDATION               
5.1    conclusion                                   
5.2    Recommendation                      
REFERENCE                                   
LIST OF FIGURES
Fig 3.1 flow chart for preparation of pleurotus tuber regium (Osu) for storage
LIST OF TABLE
Table 1: result of the proximate composition of the fruit body of pleurotus tuber-regium.   
Table 4 shows the nutritional/proximate composition of pleurotus tuber regium.
Table 5 shows the mineral content of pleurotus tuber regium             
CHAPTER ONE
1.1    Background of the Study
Edible mushrooms are fungi and belong to the class basidiomycetes. They have been found to provide a rich addition to the diet in the form of protein, carbohydrate, minerals, vitamins and enzymes (Justo et al., 2005). The consumption of edible mushroom in Nigeria is seasonal. Most people only consume them because of their unique flavours and not really for their nutritional composition. At the moment mushrooms are only hunted and harvested from the wild, however, if the food composition is elucidated and people get aware of certain important components of it, this will encourage cultivation and subsequent industrial production (Patrabansh and Madan, 2009). Pleurotus tuber regium, as an edible basidiomycete occurs on both tropical and subtropical regions of the world (Zoberi, 2009). It is a common mushroom in the southern part of Nigeria and forms large spherical to ovoid, subterranean sclerotia which sometimes measures up to 30cm in diameter (Oso, 2015). The fungus feeds on dry wood, when it produces the sclerotium usually buried with in the wood and the bark. Bothe the sclerotium and mushroom are eaten in Nigeria. Pleurotus tuber regium has great medicinal value among the native doctors in the treatment of many ailments, including asthma, small pox, and high blood pressure Oso (2007).
The pleurotus tuber regium is dark brown on the outside and white on the inside. In Nigeria it is used both as food and medicine, the sclerotium which is hard is peeled and ground for use in a vegetable soup (Okhuoya, and Okogbo, 2009). It may also be dried for future use, various kinds of available agricultural wastes can serve as an ideal substrate for the growth of pleurotus tuber regium; the cost of production can be quite low and adoptable to low technology method. Sclerotium can be soaked in water for 12-24hrs and after the skin is peeled off, the whitish inner tissue is milled into paste, the paste is used as adjunct to melon seed in the preparation of ‘egusi’ soup, Egusi cake, a high protein delicacy called ‘Osu’ in Ibo is produced by blending pleurotus, melon seeds and crayfish together.
1.2    Statement of the Problem
Pleurotus tuber regium is known to be nutritional and medicinal important. In most African countries pleurotus tuber regium is subjected to different storage methods in other to prevent them from spoilage. These plants are stored for period of time before consumption, due to these situation their is need to investigate if the storage period have any effect on the nutritional and mineral content of the plant. If the level of nutritional factors in pleurotus tuber regium is understood after storage, safe and wholesome consumption can be guaranteed.
1.3    Aim of the Study
To evaluate the effect of storage period on the nutritional and mineral content of pleurotus tuber regium (Osu).
1.4    Specific Objectives
The specific objectives of the study are to:
 Source the pleurotus tuber regium from the dry wood which serves as an ideal substrate for the growth of plant.
  Store the pleurotus tuber regium for two and three weeks as follows before analysis.
  Examine the stored pleurotus tuber regium to check the nutritional and mineral content, in other words to know the effect of storage on the.