SCIENCE

CHAPTER TWO

LITERATURE REVIEW

T

he term ‘fermentation’ is derived from the latin verb called Fevere, which means to boil.

Fermentation technology is one of the oldest food technologies that have been used for several thousand years as an effective and low cost means for preserving foods and beverages.

Food fermentation is of prime importance in the developing countries where the limitation of resources encourages the use of locally available fermented food products for additional nutrition. These fermented products are more common among people belonging to rural areas, without much awareness about the micro flora involved in their production. In the past few years, great emphasis has been given to identify unknown microflora associated with these products. This micro flora involves a combination of bacteria, yeast and fungi which have been

Reported by several workers from various fermented foods viz.

The most important organism associated with fermentation is yeast. Yeasts as a group of micro-organisms have been commercially exploited as a fermentative species to carry out alcoholic fermentation, especially Saccharomyces cerevisiae.

The importance of this microorganism has urged many scientists to study the factors governing its growth, survival and biological activities in different ecosystems. Cerevisiae plays a prominent role in controlling the quality and flavor of the final product in wine fermentations and that’s why, it has received considerable attention in fermentation industry to obtain the best strain, knowledge of S. cerevisiae diversity associated with a particular fermented productin a given area,is of prime importance.

TAKING PALM WINE AND RED WINE AS A REFERENCE POINT

Palm wine is the fermented sap of various palm trees especially Palmyra, silver date palm and coconut palms. Palm wine can be obtained from the young inflorescence either male (or) female ones palm wine is alcoholic beverage that are made by fermenting the sugary sap from various palm plants. It is collected by tapping the top of the trunk by felling the palm tree and boring a hole into the trunk it is a cloudy whitish beverage with a sweet alcoholic taste and very short shelf life of only one day, the wine is consumed in a

variety of flavors varying foam sweet unfermented to sour ,fermented and vinegary there are many various of the products and no individuals method or recipe palm wine is particularly common in parts of Africa, South India , Mayanmar and Mexico some of the local names for the product include emuand ogogoroin Nigeria and Nsafufuoin Ghana, kallu in south India and tuba in Mexico. Palm sap can be fermented (or) processed into an alcoholic beverage it just needs the correct the yeasts, temperature and processing conditions Throughout the world alcoholic drinks are made from the juices of locally grown plants including coconut palm, Palmyra and wild date palm. The term toddy and palm wine both used to describe similar alcoholic drinks the terminology various from country to country in parts of India the unfermented sap is called “Neera” The wine is an excellent substrate for microbial growth fermentation starts soon after the sap is collected and withinan hour (or) two. Becomes reasonably high in alcoholic (upto 4%) if allowed to continue to ferment for more than a day, it starts turning into vinegar.The sap should be collected from a growing palm. It is collected by tapping the palm this involves making a small incision in the bark about 15cm from the top of the trunk a clean gourd is tied around the tree to collect the sap which runs into it the sap is collected each day and should be consumed with in 5-12 hours of collection fresh palm juice is a sweet, clear, colorless juice containing 10-12% sugar.

Palm wine contains good amount of yeast, though there are other formulated.

Yeast tablets, it is also beneficial to the body as well.By using palm wine to produce spirit. Palm wine is distilled to obtained spirit known as illicit (or) gin (or) kai-kai.

In Sri-lanka the sugar in palm sap is utilized in the production of “Coconut honey” and “jaggery” most palm sap produced in that country is used for these purpose

Palm wine under goes longer fermentation produces vinegar. Pam wine is used for making vinegar as acetificatio occurs after alcoholic fermentation of the wine it is used for making house hold vinegar in Asia. In Nigeria there is an increasing interest in vinegar production from palm wine.Palm wine from the fermentation results roomie palm sugar is also useful as menstruation Zest. In addition drink palm wine roomie is a powerful enough to fight

Pneumonia and mejan, palm sugar and has the properties as a drug fever and stomach pain. Palm wine and its distillate are important solvent in herbal –medicinal administration, pregnant women consume it fresh for the sweetness and nutrition while nursing mothers

drink it warm to enhance breast milk production. Palm wine serves as a source of inoculum for other fermentations. In Asia it is the source of inoculum for cottage industry fermentations such as Nan (a native leavened bread) and Sonnon (steamed rice flours plus palm wine)

Palm wine yeast is found capable of degrading hydrocarbons in kerosene and diesel (oil spills) confirmatory evidence was derived from gas chromatographic analysis yeast used hydrocarbons as a carbon source and energy source for growth by these isolate

Suggest its potential application in oil spill cleanupas well as in single cell protein production using hydro carbon feed stocks.

Palm wine contains Microbes it enhances the

fermentation of the palm sap

MICROBIAL ANALYSIS

From the Microbial analysis Palm wine include both Yeast and Bacteria. Palm wine yeast isolated from freshly tapped palm wine from different palm trees, identified as Schizo saccharomyces pombe, Saccharomyces cerevisae, Debaryomyces hanseniiand

Zygosaccharomyces rouxii, each of this isolates was used to ferment wheat flour dough

baked, sensory analysis of dough’s was carried out on leavening, texture, aroma, taste and appearance.

PALM WINE YEAST ISOLATES FOR INDUSTRIAL UTILIZATION.

The isolates were characterized for certain attributed necessary for ethanol production

Palm wine consists of many bacteria mainly Lactic acid bacteria include Streptococcus, Pediococcus, Leuconostoc and Lactobacillus. Lactobacillus plantarum and Leuconostoc mesenteroides were the dominated lactic acid bacteria. Acetic acid bacteria were also isolated the pH of the lactic acid and acetic acid concentration 3.5-4%, 0.2-0.4% Zymomonas mobillisis a bacterium belonging to the genus Zymomonas.

Isolated from alcoholic beverages like the palm wine. Zymomonas mobillis degrades sugar to pyruvate using the Entner-Doudoroff pathway. The pyruvate is then fermented to produce ethanol and carbon dioxide as the only products.

The advantages of Z.mobillis over S.cerevisiae, with respect to producing Bio-ethano