Imran project work docx

To assess the utility of fermentation in preserving carrots, pH, specific gravity, reducing sugar, alcohol content and viable yeast counts atdays 0, 7 and 14 of fermentation were obtaine

ABSTRACTThe preservation of nutritional constituents of perishable vegetables including

carrots (Daucus carota) is important to prevent substantial losses Fermentation

apart from offering a means of producing a special group of food items as itsprimary objectives, it also helps in the prolongation of shelve-life of food materials

in areas where other methods of preservation is technically and economicallydifficult to implement To assess the utility of fermentation in preserving carrots,

pH, specific gravity, reducing sugar, alcohol content and viable yeast counts atdays 0, 7 and 14 of fermentation were obtained Significant changes whereobserved of these parameters at different intervals pH(4.29, 3.81, 3.53).S.G( 1.016, 1.015, 1.002) Reducing Sugar in mg/ml (5.85, 4.13, 2.99) Alcoholcontent in %(4.04, 8.99, 11.19) Yeast count in cfu/ml (2.7x106, 4.8x106, 3.1x105

CHAPTER ONE

Over the years, certain measures have been taken by man in order to increasethe shelf life of our foods and food items (food preservation) from attack byspoilage microorganism This measure ranges from traditional to modernmethods of food preservation This includes drying, salting, sugaring, smoking,pickling, refrigeration, freezing, canning, pasteurization, fermentation and many

other methods

Fermentation is one of the methods used for food preservation preservation), fermentation can be define as a process in which chemicalchanges are brought about in an organic substrate through which the action ofbiochemical catalyst called enzymes elaborated by specific types of livingorganisms (Robinson and Tamime 2006) It can also be seen as metabolicprocess that converts sugar to acids, gasses, and/or alcohol Fermentationinvolves the use of organisms like yeast, mould, and bacteria Yeast is employed

(bio-in the production of alcohols, w(bio-ines, beers, and other alcoholic beverages.Bacteria also have been involved in acetic acid, butyric propionic acid and

lactic acid fermentation (Marica et al 2007) Fermentation is also used more

broadly to refer to bulk growth of micro organisms on a growth medium, often

with the goal of producing a specific chemical product i.e ( continous and batch

cultures)

With many countries in Africa producing reasonable amount of the worlds fruitsand vegetables for instance carrots, with an estimate of about less than 6% ofworlds 2012 total production was in Africa The world total production stood at21.4million tones in 2012 (FAO, 2013) Nigeria is one of the Africa countrieslocated on the latitude 40 to 140 N and longitude 20 to 150E, blessed with manynatural edible fruits and vegetables most of these vegetables and fruits are soldraw in the markets of cities and towns across the country during their seasons.Also most of these fruits and vegetable rot away due to under consumption and

utilization

The French microbiologist Louis Pasture is often remembered for his insightinto fermentation and its microbial causes The science of fermentation isknown as Zymology In general, fermentation procedures a product that is lesssusceptible to undesirable microbial activity than the original material Itremoves or reduces the amount of unstable constituents and converts thefermentable portion into products that is stable and in most cases is present insufficient concentration to act as a preservative For instance Vinegar, Cheese,and fermented foods are more flavor full than the raw materials used The flavormay be desirable to the extent that the fermented product is used to flavor otherfoods (Stainkraus, 1995)

To many people, fermentation simply means the production of alcohol, grainsand fruits are fermented to produce beers and wine If a food soured, one might

say it was “off” or fermented (Tortora, et al., 2010) Fermentation apart from

offering a means of producing a special group of food items as its primaryobjectives The prolongation and the keeping quality of food, raw materialsespecially when practiced or propagated in areas where other methods ofpreservation and technically and economically difficult to implement Alcoholicfermentation is applied to the production of matured palm wine, beer, stout,wines and other alcoholic beverages In this type of fermentation sugars areconverted to ethanol and carbon dioxide (Voet and Voet, 1995)

The fermentation of monosaccharide by yeast involves exactly the samereaction as glycolysis in animal tissues down to the production of pyruvic acid.Many different types of yeast can be used to bring about this type of

fermentation but the most commonly employed is genus Saccahromyces (Voet

and Voet, 1995)

Fermentation does not necessarily have to be carried out in an anaerobicenvironment For example, even in the presence of abundant oxygen, yeast cellgreatly prefer fermentation to anaerobic respiration as long as sugars are readilyavailable for consumption a phenomenon known as Crab tree effect (Dickson,

as well as the microorganism involved in the fermentation process for a variety

of food and drinks Ethanol fermentation is also called alcoholic fermentation,and it is the production of ethanol and carbon dioxide Lactic acid fermentation

refers to two means of producing lactic acid:

• Homolactic fermentation : which is the production of lactic acid extensively

• Heterolactic fermentation: is the production of lactic acid as well as other

acids like acetic acid, ethanol, and carbon dioxide

Sugars are the most common substrate of fermentation and typical example

of the fermentation products are ethanol, lactic acid, carbon dioxide andhydrogen, however more exotic compounds can be produced byfermentation such as butyric acid and acetone, yeast carries out fermentation

in the production of ethanol in beers, wines and other alcoholic drinks alongwith the production of large quantities of carbon dioxide Fermentation alsooccurs in mammalian muscle during periods of intense exercise whereoxygen supply becomes limited resulting in the creation of lactic acid (Voet

and Voet, 1995)

The art of wine making is an ancient practice but modern methods arecarefully controlled borne out of science research The essential stages inwinemaking are pressing, fermentation, casking and bottling In pressing, thejuice is extracted from fruits or vegetable and a starter culture is introduced.Many different types of may be present on a single type of fruit orvegetable and because many of them are wild yeast that would produce poor

quality wine, sulphur dioxide (SO2) is added to the juice in such a quantitythat all the wild microorganism are destroyed (Querol and Fleet, 2006) Thefermentation continues until all the sugars are used up In any case, yeastcannot tolerate any alcohol content that is greater than 16% as such naturalwine do not have alcohol content greater than this In general they containabout 10% (Solomon and Fryle, 2002) After fermentation is transferred tocask where it may remain for up to five years, during these time sediments isoccasionally removed and wine matures due to slow chemical changeswhich contribute to flavor and bouquet (Robinson, 2006) The alcoholicrange of wine is greater than that of beer but not up to that of spirit i.e Itsalcoholic ranges between 10-12% It may however be as low as 7%, at timeand sugar concentration is about 15-25% There are three main classes of

wine;

• Table wines: contain 6-14% v/v alcohol produce by spontaneous

fermentation by organism in the juice e.g mosell cret, Hock

• Sparkling wines: which are given a second fermentation in the bottle so that

a visible excess of co2 is produced e.g champagne

• Fortified wines: containing about 2% v/v alcohol made by addition of spirit

to wine e.g portsherry, Madeira

1.1 AIMS AND OBJECTIVES

This study tends to:

• Evaluate the short term process of producing wine from carrot juice

• Evaluate the effect of yeast on carrot juice for production of wine

CHAPTER TWO

2.0 LITERATURE REVIEW.

2.0.1 Carrot

Carrots (daucus carota) are more than a versatile orange vegetable Original

carrots were purple and yellow, initially described in the 10th century in Iran

and northern Arabia (Simon, 2004) Daucus carrota subsp Sativus is a root

vegetable usually orange in color, though purple red, white and yellowvarieties exist It has a crisp texture when fresh The most commonly eatenpart of the carrot is the tap root, although the greens are sometimes eaten as

well It is a domesticated form of wild carrot Daucus carota, native to

Europe and southern Asia The domestic carrot has selectively been bred forits greatly enlarged and more palatable and less woody-textured edible

taproot (Simon, et al 2012) The food and agriculture organization of the

United Nations (FOA) reports that the world production of carrots andturnips (these plants are combined by FOA for reporting purposes) forcalendar year 2011 was almost 35.658 million tones Almost half weregrown in china Carrots are widely used in many cuisines especially inpreparation of salad and carrot salads are traditional in many regional

cuisines

E tymology: the word was first recorded in English around 1530 and was

borrowed from middle French carrotte (Online dictionary, 2014) Itself from

late latin carōta, from Greek καρότονkarōton, originally from the

Indo-European root ker- (horn), due to its horn-like shape) It is a biennial plantthat grows a rosette of leaves in the spring and summer, while building is thetaproot that stores large amount of sugars for plant to flower in the second

year, the stems grow up to 60-200cm (20-80inch) tall (Rubatsky et al 1999).

Binomial name: Daucus carota

Source: Bradeen and Simon, (2007)

2.0.2 History

Carrots were first cultivated in Persia (region of Afghanistan, Pakistan and Iran)some 5000 years ago Wild carrots are white or yellow Through domestication, thecolors change to purple, yellow and orange The modern orange color appears tohave come about through a combination of mutation and selection Daucus carota

subsp sativus, to reduce bitterness, increase sweetness and minimize the woody

core, this has produced the familiar garden vegetable (Rose, 2006 and Mabey,1997) When they were first cultivated, carrot were grown for their aromatic leaves

and seeds rather than their roots Carrot seeds have been found in Switzerland and

Southern Germany dating to 2000–3000 BC (Robatsky el al.,1999) The plant

appears to have been introduced to Europe via Spain by the moors in the

18thcentury (Krech et al., 2004) And 10thcentury in such locations in west Asia,India and Europe, then the roots were purple (BBC, 2010) The 12thcentury Arabandulusia agriculturist, ibn-al’auwam, describes both yellow and red carrots (staub,2010) Cultivation of carrots appeared in china in the 14thcentury and Japan in the

18thcentury (Dalby, 2003) Those modern carrots were intended by antiquary JohnAubey (1626-1697) when he noted in the memoranda Carrots were first sown atBeckington in Somersetshire, Some very old Man there [in 1668] did rememberthey are first to bring it." European settlers introduced the carrot to colonialAmerica in the 17th century (Robatsky et al., 1999)

Currently, the largest producer and exporter of carrots in the world is China In

2013 33.5million tonnes of carrots and turnips were produce worldwide With15.8million in china, 1.3million tonnes in United states, 1.3million tonnes inRussia, 1million tonnes in Uzbekistan and less than a million in Poland, unitedkingdom and Ukraine Through documentation of domestication and historical

development of carrots have been published (Rubatsky et al., 1999; Simon 2000).

The nutritional value of carrot, nutritional improvement researchers have madethrough biofortification, the bioavailability of pigment from carrots and theirimpact on vitamin A status and finally putative health benefit attributed to carrotswhole food-based approaches to enhance health by utilizing functional food likebiofortified carrots are currently popular (Jacobs and Tapsell, 2007)

2.0.3 Nutritional importance of Carrot

Carrot is an economically important crop that has gained popularity in recentdecades due to increase awareness of its nutritional value Orange carrot are highlyrevered as ‘good for the eyes’’ due to their high content of hydrocarboncarrotenoid, a class of phytochemical that are often precursor to vitamin A

The storage root of carrot is the most commonly consumed portion of the plant,although the tender young foliage is occasionally used as stir-dried herb and insalad in china and Japan (Rubatsky et al., 1999) Carrot roots do not supply a

significant amount of calories to human diet but do supply nutrition in the form ofphytochemicals such as carotenoids, anthacyanins and other phenolic compounds.

Carrots roots is approximately 88% water, 1% protein,7% carbohydrate 0.2%fatand 3% fiber (USDA, 2008) The carbon fraction is almost exclusively simplesugars, predominantly sucrose, glucose, xylose and fructose with small amount ofstarch (USDA, 2008) The fiber comprises mostly cellulose with smaller

proportion of hemicelluloses and liginin (Rubatsky et al 1999) Content of dietary

fiber and digestible carbohydrate can vary between cultures and also during

processing and storage (Svanberg et al 1997) Nitrite and nitrate contents are about

40 and 0.41 milligram per 100gram (fresh) respectively Most of the taste of thevegetable is due to glutamic acid and other free amino acids Other acids present intrace amount includes succinic acid, &-glutamic acid, lactic acid and glucose acids,

the major phenotic acids is Caffeic acid (Sharma et al 2012).

The carrots get its characteristic and bright orange color from B-carotene, andlesser amounts of a-carotene and &-carotene, a-B-carotene are partly metabolized

into vitamin A in humans (Strube and Ovedragsred, 1999; Novotmy et al., 1995).

Carotene is the predominant carotenoids although there are lesser amount of carotene and &-carotene There are typically between 6000 and 54000 micrograms

a-of carotenoids per 100gram a-of carrot root Carrot extracts are used by poultry

producers to improve animal skin alter the color of egg yolk (Rubatsky et al.

1999) Massive over consumption of carrots can cause carrotenosis, a benigncondition in which the skin turns orange (Haas and Levis, 2012) Carrots are alsorich in antioxidant and minerals (Cohen and Dubois, 2010) Echnomedically, theroots are used as an emmenagogue (to increase blood flow in the pelvic area anduterus) a corminative (to reduce flatulence) to treat digestive problems, intestinalparasites, and tonsillis or constipation (Ross, 2005)

Lack of vitamin A can cause poor vision, including night vision and these can berestored by adding vitamin A to the diet An urban legend states that eating a largequantity of carrots will allow one to see in the dark This myth developed fromstories about gunners in World War II, who were able to shoot down Germanplanes at night The RAF (Royal Air Force) circulated a story about their pilotscarrot consumption in attempts to cover up the discovery and effective use of radartechnologies in engaging enemy planes as well as the used of red light (whichdoes not destroy night vision) in air craft instrument ( Kruszehicki, 2010) Thereinforced existing German beliefs and helped their night vision during blackout togrow and eat the vegetable which was not rationed like most others foodstuff Acarrot advertising campaign encourage its consumption ( Kruszehicki, 2005)

2.0.4 Means of consumption and uses

Carrots can be eaten in a variety of ways Only 3% of B-carroten in raw carrots isrelease during digestion This can be improved to 39% by pulping, cooking and

adding cooking oil (Hedren et al., 2002) Alternatively, they can be chopped and

boiled, fried or steamed, and cooked in soups and stews as well as baby and petfoods A well known dish is carrot Julienne (Martino and Roberts, 2006) Togetherwith onion and celery, carrots are one of the primary vegetables used in a mirepoix

to make various broths (Gisslen,2010)

The greens are edible as a leaf vegetable, but are only occasionally eaten by

humans; (Rubatsky et al., 1999) When used for this purpose, they harvested young

in high density plantings before significant root development and typically used

stir-fried, or in salads (Rubatsky et al., 1999).

In India carrots are used in a variety of ways, as salads or as vegetables added tospicy rice or dal dishes A popular variation in north India is the Gayar Ka Haluacarrots desserts, which has carrot grated and cooked in milk until the wholemixture is solid after which nuts and butter are added (Gupta, 2000) Carrot saladsare usually made with grated carrots with a seasoning of mustard seeds and greenchilies popped in hot oil

The sweetness of carrots allows the vegetable to be used in carrot cakes as well ascarrot puddings, an English dish thought to have originated in the early 19thcentury Carrots can also be used alone or with fruits in Jam and preserves Carrotjuice is also widely marketed, especially as a health drink; either stands alone orblended with fruits and other vegetables (Shannon and Nomi, 1998) Since the late1980s, baby carrots or mini-carrots (carrots that have been peeled and cut intouniform cylinders) carrots are pureed and used as baby food, dehydrated to makechips, flakes and powder, and thinly sliced and deep-fried, like potato chips

temporary carotenoderma, a benign skin condition resulting in an orange hue to theskin Drinking more than 3 cups of carrot juice in 24hours period over an elongatedtime may be adequate to cause the disorder Carrots have been made into soups,juices and wines for hundreds of years In America carrot juice was one of the firstcolorant used to make cheese a darker color.

2.0.6 BEVERAGES

Beverages are liquids specifically prepared for human consumption In addition tobasic needs, although all beverages including juice, soft drinks and carbonateddrinks have some form of water in them Water itself is not classified as abeverage

Alcoholic beverages

An alcoholic beverage is a drink containing ethanol commonly known as alcohol(C2H5OH) This ethanol is almost always produced by fermentation, themetabolism of carbohydrates by certain species of yeast under low oxygen oranaerobic conditions Beverages such as wine, mead and beer or distilled spirit all

uses yeast at some stage of their production (Legras et al., 2007) Non-alcoholic

beverages often signify drinks that would normally contain alcohol such as beerand wine but are made with less than 5% alcohol volume

Carbohydrate-containing plant materials are fermented by yeast to producing dilutesolution of ethanol in the process Spirit such as whiskey and rum are prepared bydistilling these dilute solution of ethanol Components other than ethanol arecollected in condensate including water, esters and alcohols Which account for

flavor of beverage (Dunn et al., 2005).

2.0.7 Wine Yeast.

The useful physiological properties of yeast have led to their use in the field ofbiotechnology The role of yeast in wine making is the most important element thatdistinguishes wine from group juice In the absence of oxygen yeast converts thesugars of wine grapes into alcohol and carbon dioxide through the process offermentation (Jef, 1999) Many types of yeast are used for making foods; baker’syeast in bread production; brewer’s yeast in beer fermentation; yeast in wine

fermentation and for xytole production (Rao et al., 2004) Yeast used in wine

making, where it converts the sugar present in juice (must) into ethanol Yeast isnormally present on grapes or vegetables skins Fermentation can be done with thisendogenous wild yeast (Ross, 2012) But this procedure gives unpredictable resultwhich depends upon the exact type of yeast species present The natural microflora(wild yeast) in grapes are treated with SO2 (sulpurdioxide) in control fermentation

Most yeast of industrial importance are those of genus saccharomyces mostly

saccharomyces cerevisae Yeast for a given purpose may be improved for its use

but must also be guarded against undesirable changes when used in fermentation

(Gonzalez et al., 2001) Strain of S cerevisae are used in wine-making and is

adapted to specific type of wine, they can grow in highly acidic condition (PH 3-4)and resist 10% or more alcohol, resist the sulphurdioxide which is added to repressspoilage The amount of yeast growth is limited by oxygen supplied and of nutrientand accumulation of inhibiting metabolic products (Robinson, 2006) Pure cultures

of yeast that are grown in the lab are often freez-dried and packaged forcommercial use

2.0.8 GENERAL WINE-MAKING PROCESS.

The process of wine production has remained much the same throughout ages Butnew sophisticated machinery and technology has helped streamline and increasethe output of wine These advances include a variety of mechanical harvesters,grape crushers, temperature controlled tanks and centrifuges The wine-makingprocess can be divided into harvesting; crushing and disteming; juice preparation;fermentation; purification; and packaging

Step 1- Harvesting:

As the grapes ripen, the concentration of sugars and aroma compounds rises andthe concentration of acids falls The aim at harvesting is to pick the grapes at theiroptimum composition This depends on the type of wine to be produced forexample, sparkling wine requires a higher acidity than still table wine Thedevelopment of grapes is followed by taking samples of grapes at regular intervalsfrom a few weeks before the expected optimum levels will be reached Thesamples are analyzed for PH (using PH meter), acid (by titration with sodiumhydroxide), sugar (by refractive index or chemical reduction of copper salt) andflavor compounds (by tasting) When optimum levels are reached, the grapes areharvested (Lum, 1998)

Step 2- Crushing and destemming

Sulphurdioxide (5-10% solution of metabisulphite) is usually added to the grapebunches as they are fed into the crusher/destemmer, the stems are removed as thebunches pass through a perforated rotating cylinder in which the grapes fallthrough the perforations while the stems are separated out by beathers The berriesare then passed through rollers and crushed The SO2 inhibits the growth of wild

microorganisms and prevents oxidative browning of the juice Molecular SO2 isactive biocide, but in the solution this is in equilibrium with active HSO3- At wine

PH only 2-8% of SO2 exist in the molecular form, but this is usually sufficient togive the required protection Whenever possible during the manufacturing process.The juice is kept under a blanket of CO2 to exclude air, and if necessary more SO2

is added to maintain the level of SO2 at a minimum of 80ppm (Lum, 1998)

Step 3- Juice preparation

The free run juice is separated from the crushed berries which are pressed bygentle squeezing to obtain a high quality juice The juice is allowed to settleovernight or centrifuged to clarify it If necessary proteolytic enzyme are added toremove haze Finally, the pulp is then squeezed almost dry This final juice is oflow quality and is used for cask wine or fermented for distillation into alcohol forsherry or port production (Lum, 1998)

The driving force behind this reaction is the release of energy stored in sugar tomake it more available to other biological process In anaerobic conditions thereaction can proceed further and convert ethanol to H2O and CO2 releasing all ofthe energy present in the original sugars This process is undesirable in wineproduction, so fermentation is usually carried out under a blanket of CO2 toexclude oxygen and hence maximize alcohol production Depending on theconditions various intermediate in fermentation process can be converted into otherproducts The yield of ethanol is affected by such factors as temperature, extent ofagitation, sugar concentration, acidity, strain of yeast and yeast activities (Lum1998).

The lower the temperature, the higher the alcohol yield due to more completefermentation (better sugar utilization) and less loss of alcohol entrained with CO2.While it may be important to maximize the yield of ethanol is equally importantthat this is never achieved with efficiency, the various by-products of yeastmetabolism formed by this inefficiency contribute to wines distinctive flavor andaroma and prevent it from simply being alcoholic juice The juice used to befermented in wax-lined concrete or plastic vats, but new stainless steel is used forall wines except for certain high quality ones that are fermented in wood Woodenbarrels are containers of choice for chardonnay, sauvignon blanc and pinotor as the

wood is smoked during processing, forming additional flavor compounds(particularly tannis) which are leached into the wine, giving it further (Lum 1998).Step 5- Purification

In former times, after fermentation was complete, the wine was heavily treated toalter the pH, composition e.t.c to give it a desirable flavor, appearance e.t.c Veryfew such measures are used today but those that are retained are outlined below.Proteins and tannins that are suspended in colloidal form in the wine areprecipitated out with substance such as gelatin or absorbed to the surface ofsubstance bentonite This process is often called racking, this is the drawing off thewine from lees (sediment form) Wine is often also cold stabilized (left at 0-30c for10-14days) to crystallize out any potassium biratarate (KHTa) These treatmentsare only necessary in white wine, as red wine fines and clarify itself by formingdeposit of protein, tannins and tartrate during the ageing process Although,sometimes proteinacous fining agents are added to modify tannins level andstructures The wine is continually racked off this precipitate such that by the end

of ageing process all it needs is simple filtration before bottling and seal (Lum,1998)

Step 6- Packaging

Most medium to large sized wineries now use automated bottling machines.However, in this stage cleanliness and sanitation are extremely important in thisoperation The blended wine is pasteurized and corked The principle of bottlingwine against spoilage organism or deterioration organism and oxygen Good winescan often be spoiled or damaged by extreme aeration during bottling or byinfection of spoilage organisms or by improper corking or sealing Corks should besterilized and bottles should be scrupulously cleaned The aroma, taste of wine aredetermine by varieties of fruits used, chemical compositions, nature offermentation process and changes which are made to occur naturally during thepost fermentation period Color bottles are used so as to keep out the adverse effect

of light upon ageing (Lum,1998)

2.0.9 SPOILAGE OF WINE

A wine fault or defect is an unpleasant characteristic of a wine often resulting frompoor wine-making practices or storage conditions and leading to wine spoilage.Many of the compounds that cause wine faults are already naturally present inwine but at insufficient concentration to adversely affect it In-fact, depending onthe perception, this concentration may impart positive characters to the wine.However when the concentration of base compounds greatly exceeds the sensory

threshold, they replace or obscure the flavors and aromas that wine should beexpressing (or that the wine maker wants the wine to express) Ultimately thequality of wine is reduced, making it less appealing and sometimes undrinkable(Baldy, 2009).

Even after bottling with adequate sterilization procedure wine is liable to microbialspoilage Attacked wine will often show microbial growth which is characteristics

of microbe involved and development of cloudiness in the bulk Taste and bouquetare altered considerably by chemical changes brought about by microbialrespiration and generally this related both to increase in volatile acidity and theproduction of carbon dioxide and temperature of storage (Bird, 2005)

Factors that influence spoilage by Microorganism includes:

• Alcohol: inhibits most microbes including yeast if above 15-18%

• Acidity: The lower the pH, the more difficult it is for the microorganism tosurvive

• Residual Sugar: existence of fermentable sugars facilitates the risk ofspoilage specifically by yeast

• Sulphur dioxide: a concentration of free 200mg/l will inhibit microorganismfrom growing.

• Growth Factors: e.g nutrients such as amino acid and vitamins

• Temperature: growth is usually fasted at 20-35oc and only slow at cellulartemperature (10-15oc)

• The Extent of Initial Contamination by Microorganisms during bottlingprocess

• Air(Oxygen) : essential for growth of aerobic acetic bacteria

When proper hygiene is practiced, bacterial spoilage is rare When itdoes occur, the microorganisms concerned are usually acetic acid bacteria,

which cause sourness in wine Lactic acid bacteria espessially leuconostoc and sometimes lactobacillus also spoils wine Various spoilage yeast may also

grow in wine, the most prevalent are slow growing yeast such as

zygosaccharomyces and brettanomyces and their presence in wine can result

to wine faults and subsequent spoilage

Brettanomyces is a significant contributor to wine faults within the wine

industry, causing turbidity and off flavor (Loureiro and Malfeito, 2003) Other

wine spoilages are saccharomyces oriformis which may use up residual sugars in sweet wine and saccharomyces bayanus which may cause turbidity

and sedimentation in dry wines with some residual sugars Other defectsinclude cloudiness and acidity (Du toit and Protorius, 2000)

2.1.0 QUALITY CONTROL

Quality control or QC for short is a process by which entities review thequality of all factors involved in production or A part of quality managementfocused on fulfilling quality requirements (ISO, 2005)

In winery, all facets of wine production maybe carefully controlled to create aquality wine Such variables as speed with which harvested grapes or anyfruits are crushed; The temperature and timing during both fermentation andageing; the percent of sugar and acid in harvested fruits or vegetable; and theamount of sulphur dioxide added during fermentation, all have a tremendousimpact on the quality of the finished wine

3.2 Carrot wine production Procedure:

1 Two kilogram (2kg) of carrots was scrubbed and cleaned very well in a largebowl of clean water then cut into tiny bits that made it easy for blending

using clean stainless steel knife

2 Blender was used to blend the tiny pieces of carrots

3 Distilled water was added to make it 4litres

5 One point six gram (1.6g) of Sodium metabisulphite was added to the juiceand left in an open vessel covered with folds of muslin cloth for 24hrs (this

is to allow the sulphur dioxide generated by the potassium metabisulphite to

inhibit the growth of any wild yeast or organisms present in the juice)

6 After 24hrs of exposure of the juice to induce and incorporate some oxygen

or air into the “Must” The extracted juice was poured into the sterile

aspirator jar

The test was carried out to determine pH level, amount of sugar, alcohol

content, specific gravity and viable yeast cells

7 Juice was ready for fermentation; 8g of instant baker’s yeast was sprinkled

on the surface of the juice inside the jar and the air cork was fitted Themixture was allowed to give bubbles before the jar is shaken for evendistribution and left for fermentation at room temperature The acidity in the

jar would prevent contaminating microorganisms from proliferating

After 7 days of fermentation test was carried out to determine pH level,

amount of sugar, alcohol content, specific gravity and viable yeast cells

8 The “Must” was allowed to continue the fermentation for another 7 days

9 The young wine was racked after full fermentation, fermentation wasstopped by the addition of 0.4g of potassium metabisulphite to the wine andmixed thoroughly and put into a sterilized bottle for storage at chilling

temperature (Uraih, 2003; Joshi and Devender, 2005)

Test was carried out to determine pH level, amount of sugar, alcohol content,specific gravity and viable yeast cells

Note: All the materials was properly washed and sterilized The fermenting carrotjuice was observed regularly for production of gas bubbles indicating thatfermentation was still in progress Also in every 2-3 days the “Must” was observedmicroscopically and gram stained to check for contamination by unwantedorganisms.

Fig 3.1 Flow charts for the production of wine

Source: Uraih, (2003)

3.3 Carrot juice and wine analysis

The sample was taken to Biochemistry laboratory for determination of the pH,Sugar concentration, Alcohol content, Specific gravity, and Microbiologylaboratory for Viable yeast cells count

3.3.1 pH Determination

The pH of the juice and fermenting juice was constantly checked using pH meter(MicropH 2000 model) The electrode was inserted into the sample until a constantdigital value was obtained

3.3.2 Sugar Concentration

 2ml of distilled water was added to 1ml of sample followed by 2ml of DNS(dinitrosalicylic acid) reagent

 The same was done for a blank solution

 The sample was heated in a boiling water bath for 5 minutes for color todevelop

 Each sample was diluted by adding 20ml of distilled water

 Absorbance was taken at 540nm

 The sample was extrapolated on a standard glucose curve to obtain theconcentration of glucose in mg/ml (Ceirwyn, 1998)