Yeast During The Rice Wine Fermentation Biology Essay

In this survey, the consequence of different starter civilization has been studied and the activity of barm during the rice vino agitation besides being observed. The UHT milk were being mix with different sort of starter civilization. Subsequently, the yogurt mixture were being incubated and further undergoes chilling period which consequences in the coveted yoghurt. Natural yoghurt and Lactobacillus Casei Shirota had been chosen to be the best among other starter civilization as the pH is drop dramatically and this proves that, the metabolite activity was high.

As for rice vino agitation, barm was being added into the rice and being mix exhaustively. The specific gravitation and pH were being observed. The pH value of the rice vino decreasing as this proves that the sourness is increasing due to the metabolite activity of barm. The specific gravitation of the barm shows addition as this indicates that the sugar were being extracted out from the rice.

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Introduction ( 327 words )

Ethanol agitation had been found by human existences which indicates that the alteration that being caused by the bacterial action could consequences in the formation of merchandises that were gratifying to devour. For illustration, the spoilage of fruit juices can consequences in the formation of vino.An early experiment carried out by Eduard Buchner in 1896 in which he grounded up a group of cell with sand until it wholly being destroyed.

The liquid that remain were being extracted and being added to saccharify solution. He assume that agitation could non happen since the cells are dead because there are no “ life-force ” needed to transport out agitation ( Albasi et al. , 2001 ) .Agitation is the procedure which produces alcoholic drinks or acidic merchandises.

The agitation which occur fundamentally involves in the interrupting down of complex organic substances into simple substances ( Budslawski and Drabent, 1972 ) . Glycolysis provide an energy towards the micro-organism and doing sugar molecules to be split up and the negatrons were removes from negatrons to molecules ( Arici et al, 2004 ) . The negatrons were being passed around to an organic molecule such as pyruvic acid ensuing in the formation of a waste merchandise such as lactic acid, ethyl intoxicant and etc which is critical to utilised agitation ( Arici et al, 2004 ) .The production of yoghurt is chiefly through agitation by lactic acid bacteriums at the scope of 27a?°C – 40a?°C.

The mechanism by which the interactive consequence of Streptococcus spp. and Lactobacillus spp. have been good studied ( Collins and Gibson, 1999 ) .

The procedure chiefly involves in the pretreatment of milk, homogenisation, heat intervention and chilling. Many survey have been done towards the probiotic bacteriums which can be used as the starter civilization in the yoghurt production which being wellness benefits ( Shortt, 1999 ) .In the rice vino production, the terminal merchandise which is vino is resulted from glucose agitation. Glucose which is present in the rice will be broken down to organize intoxicant under favorable status of the barm ( Arici et al.

, 2004 ) . The rice vino will go on until all sugar were used up and being converted to alcohol. Based on ( Arici et al, 2004 ) , the procedure of bring forthing rice vino has two stairss where by saccharification procedure is the first measure which uses fungal in order to hydrolyze the rice amylum into sugar.The following measure which involves are using the merchandise of saccharification to ethanol which can be describe as below:In this experiment, the surveies aim to look the consequence of different starter civilization that has being used for yoghurt production and to detect the rice vino agitation in the changing of pH and specific gravitation.Materials & A ; Methods:Yogurt agitation – 276 wordThere were 6 different starter civilization that had been used which were natural yogurt, Pseudomonas sp.

, barm, Lactobacillus casei Shirota ( Yakult ) , Lactobacillus acidophilus ( vitagen ) and Lactococcus Lactis. Then, 12 milliliter of these starter civilizations were being added into 500 milliliters UHT milk and being labelled individually. The pH of the milk before and after adding the starter civilization were being taken. The mixture were being incubated at 40-46a?°C for 4 – 5 hours.

After this incubation, the pH of the yogurts mixture will be tested once more. The yogurts were being incubated at 5a?°C and the pH and besides gm stained were performed after this scarey period.Below is the flow chart which summarises the methods of yoghurt agitation:Rice vino agitation1 kilogram of cooked rice were being prepared and being placed in a room temperature when carry oning this experiment. The rice so were mix in land with starter civilization which are yeast and bit by bit being added up with about 1L of H2O until all the rice were assorted exhaustively with the barm. The pH and specific gravitation of the rice were being taken every twenty-four hours.

Below is the flow chart which summarises the methods of rice vino agitation:


Yogurt productionIn the first session of the yogurt production, 12ml of the starter civilization which are natural yogurt, Pseudomonas sp. , barm, Lactobacillus casei Shirota ( Yakult ) , Lactobacillus acidophilus ( vitagen ) and Lactococcus Lactis being inserted into the UHT milks. Then the pH were taken and being followed by incubation at 40-46a?°C.

The pH and ocular observation were taken once more and continued to under chilling phases at 5 a?°C. The concluding consequences and observation were taken.The morphology of the micro-organism in the yoghurt mixture were tested utilizing the gm discoloration methods and being visualise utilizing the microscope. In order to stipulate the individuality of the micro-organism and the quality of the merchandise, the United States Public Health Service and the gm discoloration observation were being compared.Yogurt productionTable 1: The consequence of the pH of yoghurt at different phase of agitation and the gm discoloration consequenceStarter CultureStarter pH of the UHT milkInitial pHpH after 4- 6 hours of incubation at 40-46a?°CpH after chilling period at 5a?°CObservationGram discoloration observationNatural yoghurt6.45.312.903.

69& gt ; 5a?°C – sour odor, curd on top, liquid at underside, yellowish coloring material& lt ; 5a?°C – egg and mayonnaise like odor, white in coloring material and holding thick consistenceTwo settlements ( Gram positive ) were found:Long rods, concatenationdiplococciPseudomonas sp.~ 65.504.564.84& gt ; 5a?°C – rotten odor, liquid and curd nowadays& lt ; 5a?°C – yogurt odor, low consistence, more liquidGram positive, long rod form, individual cellYeast~ 65.

244.404.56& gt ; 5a?°C – sour odor, liquid surround the curd, yellowish in coloring material& lt ; 5a?°C – sour odor, 2 stages: At the top: solid natation, underside: liquid, yellow in coloring materialGram positive, cocci, concatenation – This are the contaminationsno barm are found( Yakult ) Lactobacillus casei Shirota~ 65.

563.183.24& gt ; 5a?°C – really sweet milky odor, more syrupy, even consistence& lt ; 5a?°C – really sweet milky odor, even consistence,Gram positive with long thin rod form settlements( Vitagen ) Lactobacillus acidophilus~ 65.663.233.32& gt ; 5a?°C – rancid yoghurt odor, milky balls, thick consistence& lt ; 5a?°C – yogurt odor, more even consistenceGram positive, long rods concatenationLactococcus Lactis~66.

43.193.22& gt ; 5a?°C and & lt ; 5a?°C observations are the same- smooth and thick liquid, pick coloring material, sour like odorGram positive, cocci form in short concatenation.( degree Celsius )( B )( a )( degree Fahrenheit )( vitamin E )( vitamin D )Figure 1: The microscopic observation of ( a ) natural yogurt ( B ) Pseudomonas sp. ( degree Celsius ) barm ( vitamin D ) Yakult ( Lactobacillus casei Shirota ) ( vitamin E ) vitagen ( Lactobacillus acidophilus ) ( degree Fahrenheit ) lactococcus lactisFrom table 1, all of the starter civilization that was being used have a lessening in pH value from the inital pH to the incubated pH after undergo 40-46a?°C incubation. All of the starter civilization besides have an addition value after undergo 5a?°C scarey period. From figure 1 and table 1, the similarity and differences of morphology between all types of starter civilization was being identified. When undergone gm staining, all of the starter civilization showed violet coloring material under microscope indicates that it was gram positive bacteriums alternatively gram negative bacteriums which exhibit tap coloring material.

Under the microscopic observation, the agreement and form of the bacterium was besides being observed.Rice vino agitationThe experimentation of rice vino had been done for several yearss in which in the first twenty-four hours, the starter civilizations were being mix with H2O and rice. The measuring of the pH and specific gravitation were being taken every twenty-four hours until twenty-four hours 3.Rice vino agitationTable 2: The consequence of rice vino agitationDaypHSpecific gravitation ( centimeter )Wet saddle horse observationOcular observation0 ( put up )6.081.015Cloping in 4 with bluish discoloration visual aspectThe rice has really sweet odor. The consistence is equally distributed.13.


The rice still hold really sweet odor but even more. At the underside of the rice has some kind of liquid expression.23.


The rice looks more liquid than the twenty-four hours before. The odor had a mixture of sweet and sour-like odor. The bottom portion of the rice is in solid phase.

The consistence is medium. The coloring material turning into pick coloring material32.941.

07Cloping in ironssThere are 3 stages that can be seen which is white solid, liquid stage, and xanthous slimy liquid at the underside. The odor turning into rancid like odor.( B )( a )Figure 2: The microscopic observation of wet saddle horse discoloration utilizing LPCB during ( a ) the set up and ( B ) the last twenty-four hours of experimentation – twenty-four hours 3Based on table 2, the pH and specific gravitation were being shown. The pH were found to be diminishing each twenty-four hours with the concluding pH was 2.94. The specific gravitation shows an increasing value from 1.015 centimeter to 1.07 at twenty-four hours 2.

However, the value are maintain at twenty-four hours 3.The visual aspect and morphology were being observed through wet saddle horse techniques which use LPCB discoloration. The observation of yeast morphology can be seen at figure 2.

Discussion: 1448 words

Yogurt ProductionThe yoghurt production chiefly used micro-organism in its procedure which these micro-organism holding functions in the production of the lactic acid and commanding the olfactory property and spirit of the yoghurt. The quality of the yoghurt fundamentally depending upon the clip, temperature and the types of the starter civilization that were used in the procedure. The common starter civilization that was being used are Streptococcus thermophilus and Lactobacillus bulgaricus. The demand to command the optimal temperature for the activity of the micro-organism is of import to obtain proper yoghurt gustatory sensation and quality.

The conditions with low temperature will do the civilization to turn easy in order to to the full sour the milk and to accomplish proper gustatory sensation of yoghurt. However, higher temperature will do the starter civilization to be killed and the activity of the micro-organism will goes down and the proper yoghurt will be failed to bring forth. This is the effects that might go on when the optimal temperature is non met.The secernment of the micro-organism metabolite will lend to the gustatory sensation and spirit of the yoghurt. This secernment and formation of the metabolites are fundamentally depends on the growing rate of the micro-organism.

The incubation of the milk and starter civilization for 40-46a?°C for 5 hours is the status to help the agitation of the micro-organism in the starter civilization and bring forthing the metabolite merchandises. The temperature and clip that is being set up in this experiments are being chosen to be the optimal status for the agitation to happen ( Galesloot et al, 1968 ) and the rate of the civilization metamorphosis would be higher ( Gupta et al. , 1996 ) . If the metamorphosis of the civilization is higher, the gustatory sensation of the yoghurt will be much sweeter ( Galesloot et al. , 1968 ) .When the desired pH of the sourness is reached, the yoghurt was rapidly being chilled at 5a?°C in order to stamp down the agitation procedure and any metabolic activity of the micro-organism. This is to guarantee the quality and gustatory sensation of the yoghurt are being maintain and no farther activity of the micro-organism in order to forestall the spoilage of the yoghurt ( De brabander et Al, 1999 ) .

This is of import to gauge the criterion of the yoghurt merchandise.There were 6 different starter civilization that has been used in this experiment which are natural yogurt, Pseudomonas sp. , barm, Lactobacillus casei Shirota ( Yakult ) , Lactobacillus acidophilus ( vitagen ) and Lactococcus Lactis. The UHT milks that were given are at the pH of about 6.0 and these yoghurts are being incubated in the same temperature and clip.The consequence for the natural yogurt shows the diminishing pH after being incubated at 40 -46a?°C for 4 to 6 hours which are from pH 5.31 to pH 2.

90. But there is evident addition in the pH after the scarey period of 4a?°C which is to pH 3.69. The other starter civilization besides has the same form of pH which decreases after being incubated at 40-46a?°C and addition after the chilled period of 5a?°C. But for the other civilization, the pH addition after undergo scarey period at 5a?°C does non every bit obvious as the natural yoghurt.

The implicit in ground for this status to happen is that the production of the Carbon dioxide ( CO2 ) due to lactose agitation doing the pH to worsen after incubation period of 4 to 6 hours at 40 – 46 a?°C. The growing of Lactobacillus is increasing and its predominates the whole yoghurt produce more acid and doing the acids to accumulates which leads to the lessening in the pH of the yoghurt for all of the starter civilization that were being used in this experiment ( Gomes and Malcata, 1999 ) .All of the starting motor civilizations have little addition in the pH after being chilled at 5a?°C and this is non as what is being expected. The chilling period of 5a?°C should keep and command the sourness of the mixture by cut downing the metamorphosis activity of the starter civilization which present and therefore, cut downing the by-product formation at this measure ( Gomes and Malcata, 1999 ) . However, the experimental consequence does demo an addition due to several grounds. The first ground is that, there might be contaminations or other types of the micro-organism that might disrupt the activity of the Streptococcus thermophilus and Lactobacillus bulgaricus in this experiment. Hence, this break doing the low sourness and therefore increase the pH. The other possible ground is that after the cooling period, the yoghurt was non assorted doing pH gradient and the acid merely concentrated at one portion.

But, to prove the pH value utilizing the pH metre, the yoghurt was mix before proving the pH doing the acid to be distributed and ensuing in the homogeneous solution which was less acidic. This is why the consequences after chilling period for all types of starter civilization are increased.The observation that can be seen for natural yoghurt is that after being incubated at 40-46a?°C, the status for which agitation can happen is that, the yoghurt have sour odor and have the visual aspect of milky curdles on the top and liquid at underside and the consistence is thick and non even. Mostly of the ocular observation of the yoghurt with different starter civilization have this curdles on the mixture and develop some kind of rancid odor. This is because the sourness doing the break in the third construction of the protein in the milk ( Albasi et al, 2001 ) . Hence, this state of affairs produce curdles in the mixture. The odor of the mixture with different starter civilization besides have some kind of sour- like odor which can turn out that the yoghurt contain C dioxide.

Based on the consequence in this experiment, the natural yogurt has the minimal pH compared to the other starter civilization followed by yakult, lactococcus lactis and vitagen after the incubation period of 40-46a?°C. This is because the sourness shows that Lactobacillus predominates the yoghurt mixture and bring forth more acid doing decreasing in the pH. The pH after the incubation at 40-46a?°C of Pseudomonas sp. and yeast are higher compared to the other due to the acid production is lower and therefore bring forth less acerb doing the pH to be high.For the gm stained, the full consequences shows gram discoloration positive in which under the microscope the image that could be seen is in violet coloring material.

Most of the consequences are based on the expected. However for the yeast civilization, no barm being observed but the other types of micro-organism can be seen. This is due to the presence of contaminations that might be cause during the pH measuring.

At the bench, merely one pH metre were provided and this will do taint of the pH metre ensuing in the disagreements in the consequence. The possible ground for this to happen is that the barm might non being activated with the yoghurt status. This is due to the unfavorable status for the barm to turn. Hence, doing the other micro-organism to rule the yoghurt.

The consequence from the experiment showed that the natural yogurt and Lactobacillus casei shirota ( Yakult ) was chosen to be effectual starter civilization in yoghurt production due to the diminution in the pH which shows that the bacteriums were actively bring forthing metabolite by merchandise during the agitation stages happening. The high metabolite will fix the yoghurt spirit when being added with milk and fix the procedure which will forestall spoilage of nutrient and keep the quality of the nutrient.Rice vino agitationFor the rice vino agitation, the pH are diminishing across the yearss of experimentation. This indicates that agitation does occurs and bring forthing acid as it by merchandise.

The metabolite activity which occurs in the agitation are increasing, does bring forth more acids. The experimental consequences are based on what is expected.As for the specific gravitation the form that can be seen is where there is an addition in the specific gravitation from twenty-four hours o which is during the set up to twenty-four hours 2. However, there is no addition in the specific gravitation in twenty-four hours 3. The specific gravitation of the rice vino is the lowest in twenty-four hours 0 indicates that there are non much glucose being released to the solution ( xxx ) . There are addition in the specific gravitation because of the sugar which are being release to the solution are increasing as clip additions ( Zoecklein et al, 1995 ) . The addition in specific gravitation value besides indicates that the extraction of saccharide which are components in the rice to sugar are increasing due to the addition in the metabolite activity of barm. Theoretically, the sugar should be diminishing as the clip goes by as the sugar being converted into intoxicant due to fermentation procedure ( Wanapu et al, 2002 ) .

As in this experiment, in twenty-four hours 3 to twenty-four hours 4, the specific gravitation is maintain and it supposed to be diminishing as the sugar being used up for intoxicant production. This might go on because the rice vino has stopped the extraction of the sugar and transition of sugar to alcohol has merely begun. That is why the value does non demo any alterations.

This disagreements might happen because that the rice were non equally distributed and doing non all the sugar were being extracted and converted into intoxicant. The clip taken for this experiment is non plenty to turn out that there should be decrease value of specific gravitation due to the glucose being used up.


From the experiment, the best chosen starter civilization were natural yoghurt and Lactobacillus Casei Shirota ( Yakult ) as the pH from initial pH undergo dramatic diminution when agitation procedure were done. The lessening in the pH value during this phase indicates the metabolic procedures were being done and bring forthing the by merchandise which is acidic. The pH value of the rice vino agitation besides diminishing as a consequence of metabolic reaction happening bring forthing acidic by merchandises and the addition in the specific gravitation shows that the sugar are being extracted into the solution. Subsequently, the sugar will be converted into intoxicant doing the specific gravitation to be no changed.


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