Organoleptic Properties Evaluation of Goat Milk Yoghurt with White

Rice Bran Flour Fortification

A. E. P. Haskito

, A. Setianingrum, F. N. A. E. P. Dameanti, M. Fatmawati

Faculty of Veterinary Medicine, Brawijaya University, Puncak Dieng Eksklusif Dau

Malang 65151

Keywords: Rice Bran, Fortification, Hedonic, Hedonic Quality, Organoleptic, Yoghurt.

Abstract: Yoghurt is a functional food with various health benefit. Goat milk yoghurt contains bioactive peptides

which have antioxidant potential. Rice bran is known for its good nutrition and high fiber and rich in

bioactive components as potential antioxidant. White rice bran flour fortification into yoghurt processed

from goat's milk is expected to increase the yoghurt’s nutritional value, especially in fiber and antioxidants.

The aim of this research was to create yoghurt from goat’s milk fortified by white rice bran flour and to

analyze said yogurt with hedonic test and hedonic quality test for organoleptic properties namely sour taste,

goat aroma, bran aroma, and consistency. This research’s methodology was an experimental study which

used a Completely Randomized Design (CRD) method for one treatment with five repetitions. The

treatment factor is fortificationby 4% white rice bran flour in pasteurized goat milk which has been added

with starter of Lactobacillus bulgaricus, Streptococcus thermophilus, and Lactobacillus acidophilus 3%

during incubational together until the milk transformed into yoghurt. The hedonic test and hedonic quality

tests involved 30 panelists. The data is analysed by calculating average values. The results showed that

panelists enjoyed overall characteristics such as sour taste, goat aroma, bran aroma, and yoghurt’s

consistency. The panelists stated that fortified goat milk yogurt had sour taste, no goat meat and bran aroma,

with adequately solid consistency.

1 INTRODUCTION

Freshmilk is one of animal derived products rich in

nutrition, which is obtained from dairy livestock, be it

cow, buffalo, or goat. Goat milk in general is

produced by Peranakan Etawah (PE), or Etawa

Crossbreed goat (Atmiyati, 2001). Goat milk is still

relatively unfavorable by customer for exuding

particular musky buck smell (Sampurno and Chayanti

2017). Thus, diversification effort is required to make

goat milk favored by consumers. One of these efforts

is by developing yoghurt. Yoghurt is milk product

fermented by lactic acid bacteria (LAB) in semi-solid

form which possessed texture between liquid milk

and cheese (Effendi et al. 2009). According to Balia et

al. (2011), LABs that are most often used for milk

fermentation are Streptococcus thermophilus and

Lactobacillus bulgaricus.

Milk processing via fermentation does not only

improve nutritional value but can also be used to

eliminate particular characteristic smell of fresh

milk, such as tangy and buck smell characteristic of

goat milk. In a research by Al-Baarii et al. (2003),

fermentation in goat milk may produce volatile

compounds consisted of acetaldehyde, diacetyl, and

ethanol, which may mask the smell of goat milk.

Other than fermentation, addition or fortification of

certain materials can also fix the profile of goat milk

and fermented goat milk.

Milk processing via fermentation does not only

improve nutritional value but can also be used to

eliminate particular characteristic smell of fresh

milk, such as tangy and buck smell characteristic of

goat milk. In a research by Al-Baarii et al. (2003),

fermentation in goat milk may produce volatile

compounds consisted of acetaldehyde, diacetyl, and

ethanol, which may mask the smell of goat milk.

Other than fermentation, addition or fortification of

certain materials can also fix the profile of goat milk

and fermented goat milk.

Rice bran, a by-product of rice processing, is

gaining a lot attention as functional food in the last

few years. This is related with rice bran functionality

for health (Tuarita et al. 2017). Rice bran is the by-

Haskito, A., Setianingrum, A., Dameanti, F. and Fatmawati, M.

Organoleptic Properties Evaluation of Goat Milk Yogurt with White Rice Bran Flour Fortiﬁcation.

DOI: 10.5220/0009586001170121

In Proceedings of the 6th International Conference on Advanced Molecular Bioscience and Biomedical Engineering (ICAMBBE 2019) - Bio-Prospecting Natural Biological Compounds for

Seeds Vaccine and Drug Discovery, pages 117-121

ISBN: 978-989-758-483-1

117

product of rice milling, obtained from the outer layer

of rice caryopsis (Henderson et al. 2012). Until now,

development of rice bran as functional food is still

hindered by several problem, such as the lack of

people awareness about rice bran benefit, rice bran

usage limited as livestock feed, unstandardized rice

bran quality, and the lack of interest from downstream

industry in developing rice bran. This becomes a

particular challenge for rice bran development

considering its promising health potential (Tuarita et

al. 2017). Rice bran’s role as functional food source

potential for health can be seen from its bioactive and

fiber components. Fibers in rice bran consist of

cellulose, hemicellulose, pectin, arabinosilan, lignin,

and -glucan. Bioactive component in rice bran

consist of-oryzanol,ferulic acid, caffeic acid,

tricine,kumaric acid, phytic acid, isoform of vitamin E

(-tocopherol, -tocopherol, tocotrienol), phytosterol

(-sitosterol, stigmasterol, campesterol),

andcarotenoid (-caroten, -caroten, lutein, lycopen)

(Henderson et. al., 2012). Based on tthose facts, it is

important to explore the potency of goat milk

fermented into yoghurt fortified by rice bran, which in

this research especially using white rice bran, as a

candidate of natural functional food high in fiber and

antioxidant. This research was hoped to improve

national innovation system in the development of

natural functional food product based on fermented

goat milk fortified by white rice bran flour.

2 MATERIALS

Yoghurt was made by yoghurt started containing 3

BAL strains: LLactobacillus bulgaricus,

Streptococcus thermophilus, andLactobacillus

acidophilus (Yogourmet

, Lyo-SAN INC: 500

Aeroparc, C.P. 589, and Lachute, QC. Canada, J8H,

464).White rice bran flour used was dr.Liem

. Goat

milk was obtained from Etawa Crossbreed

(PeranakanEtawa—PE) in community farm Dr.

Goat

3 METHODS

3.1 Making of Goat Milk Yoghurt

Fortified by White Rice Bran Flour

Mother working culture was made by adding 0.35

gram of starter into 70 ml pasteurized goat milk and

incubated in 45◦C for 4 hours until its pH reached

4,4-4,5. Yoghurt was then made by adding 3% of

working mother culture into 480ml of pasteurized

goat milk, added by white rice bran flour 4% in, and

then incubated in 45◦C for 4 hours until it reached

pH 4,5-5.

3.2 Organoleptic Test with Hedonic

and Hedonic Quality Test Method

Hedonic test is the most used test in measuring the

level of favorability or acceptance towards a

product. This level of preference is called hedonic

scale: extremely liked, very liked, liked, fairly liked,

and disliked. Hedonic quality test is used to identify

important sensory properties in a product and to give

information about the level or intensity of the

property. Properties to be determined in this research

are sour taste, goat smell, bran aroma, and yoghurt

existence. This research used 30 panelists with the

following inclusion characteristics: has done

organoleptic test in the past, has no allergy against

goat milk, and is familiar with rice bran. Products

and materials were provided in every panelist desk

in the following manners: (1) providing a cup of

goat milk yoghurt fortified with white rice

bran

flour, (2) providing a cup of drinking

water for

mouth washing when panelists

would like to re-taste

product, and (3) providing questionnaire for

organoleptic test.

3.3 Data Analysis

Data on sour taste, goat smell, rice bran aroma, and

yoghurt consistency were analyzed by calculating

the average value of every properties through

hedonic and hedonic quality test.

4 RESULTS

Table 1: Average Value of Organoleptic Test with

Hedonic Method.

Organoleptic Properties

Treatment

Sour

Goat

Rice

Bran Consistency

Taste

Smell

Aroma

Goat Milk

Yoghurt

Fortified by

White 1.70 2.20 2.17 2.37

Rice Bran Flour

Annotation :Hedonic Scale (1) : Dislike; (2) :neutral; (3) :

like.

ICAMBBE 2019 - 6th ICAMBBE (International Conference on Advance Molecular Bioscience Biomedical Engineering) 2019

118

In organoleptic test with hedonic method, the

result of sour taste criteria appeared to be 1.70 in

hedonic scale. This value showed that sour taste is

between 1 and 2 with the result leaning to 2 scale

value. This means panelists’ preferences on sour

taste as “neutral” for goat milk yoghurt fortified by

white rice bran flour. The result of goat aroma has

the average value of 2.20. This showed that for goat

smell criteria, it is between 2 to 3 with the scale

leaning towards 2. This means, panelists’

preferences on goat smell criteria was on “neutral”

for goat milk yoghurt fortified by white rice bran

flour. For white rice bran criteria, the value was

2.17.

This means that for the given criteria, it was

between 2 to 3 with the value leaning to 2. This

means, panelists’ preferences for white rice bran

aroma as “neutral” for goat milk yoghurt fortified by

white rice bran flour. For consistency criteria, the

value was 2.37. This means that for the given

criteria, it was between 2 to 3 with the value leaning

to 2. This means, panelists’ preferences for

consistency as “neutral” for goat milk yoghurt

fortified by white rice bran flour.

Table 2: Average Value of Organoleptic Test with

Hedonic Quality.

Organoleptic

Characteristic

Treatment

Sour

Goat

Rice

Consiste

bran

Taste

Smell

Aroma

Goat Milk

Yogh

urt

Fortifi

ed by 2.33 2.33 1.97 1.73

White Rice

Bran

Flour

Annotation: Hedonic quality scale as follow : Sour taste :

(1) inadequate sour taste; (2) sour; (3) very sour Goat

smell : (1) fairly smell of goat; (2) no goat smell; (3) smell

of yoghurt Rice bran aroma : (1) rice bran rancid smell;

(2) does not smell; (3) rice bran characteristic good

smellConsistency : (1) soggy; (2) adequate solidity; (3) too

solid.

In organoleptic test by hedonic quality method,

the result of sour taste had the average value of 2.33.

This value meant the level/intensity of sour taste was

within “sour”. The result of goat smell criteria had

the average value of 2.33. This value meant the

level/intensity of goat smell was within “no goat

smell”. The result of rice bran aroma criteria had the

average value of 1.97. This value meant the

level/intensity of rice bran aroma was within “no

smell of rice bran”. The result for consistencyhad the

average value of 1.73. This value meant the

level/intensity of consistency criteria was within

“adequate solidity”.

5 DISCUSSION

The sour taste of yoghurt came from the presence of

lactic acid as the metabolite product of BALs

activity as they utilize lactose within milk as a

source of carbon and energy (Azizah et al. 2013).

Sour taste in yoghurt is closely related to yoghurt

taste. Lactic acid produced during fermentation

process determines the sourness of yoghurt

(Anggrainin et al. 2018). In goat milk yoghurt

fortified by white rice bran flour, panelist

preferences assessment on sour taste was neutral

(average value 1.70) within level/intensity being

sour. This indicated that the use of Lactobacillus

bulgaricus, Streptococcus thermophilus, and

Lactobacillus acidophilusstarters could influence

the sour taste of yoghurt. According to Effendi et al.

(2009) Lactobacili family forms the main

components of yoghurt, which are sour taste of

lactic acid and particular smell of sour substance.

Streptococcus thermophilusforms lactic acid,

diacetyl and acetoin compounds, which would

provide characteristic smell and taste during

fermentation process. General consistency of

yoghurt is soft and thick. This is caused by the

degradation of protein molecules into peptides by

LABs activity during fermentation process that

changed milk particles into smaller molecules

(Lizyanti et al. 2014). Yoghurt consistency is

influenced by pH. If yoghurt pH is out of the range

of normal milk pH, casein protein may form whey

protein that had undergone denaturation during

pasteurization, which is the initial phase of yoghurt

making process (Azizah et al. 2013). Yoghurt

characteristic consistency is also influenced by LAB

activity during fermentation, such as Streptococcus

thermophilus, for they are able to produce lactase

enzyme, which influenced milk thickness. In

principle, lactase enzyme is used to degrade lactose

and produce lactic acid, which caused milk protein

instability, and thus also among the cause of

increasing thickness during yoghurt making

(Lizayanti et al. 2014). In goat milk yoghurt

fortified by white rice bran flour, panelists

assessment on consistency is neutral (average value

of 2.37) with level/intensity being adequately solid.

Organoleptic Properties Evaluation of Goat Milk Yogurt with White Rice Bran Flour Fortiﬁcation

119

This indicated that fortification by white rice bran

flour as much as 4% did not significantly influence

yoghurt consistency, even if white rice bran flour is

known to have relatively high crude fiber content.

Goat milk exhibit characteristic “prengus” or

musk smell that is relatively strong, which is not

found in other livestock milk and thus unfavored by

customers (Al-Baarri et al. 2003). The characteristic

smell of goat milk is caused by goat milk lipid

content which contain short and average chain lipid

acids such as capric lipid acid, caprylate lipid acid,

and caproate lipid acid that are easily turn volatile

(Setyani et al. 2003; Balia et al. 2011). Goat milk

processing into fermented milk was hoped to

eliminate or at least to reduce the must smell (al-

Baarri et al. 2003). Good yoghurt smell is if the

characteristic small of milk (musky, tangy) can be

eliminated by fermentation. Yoghurt characteristic

smell is caused by fermentation which forms volatile

compounds acetaldehyde, diacetyl, and ethanol.

Acetaldehyde is a volatile compound that gives

specific aroma to fermented milk. Diacetyl will give

“pleasant” aroma of fermented milk. Ethanol is also

a volatile compound exists in both fermented and

unfermented fresh cow milk. Higher ethanol content

is a relatively important marker in the elimination of

unfavored aroma in fresh milk before fermentation

(Al-Baari et al. 2003). In goat milk yoghurt fortified

by white rice bran flour, the preference value from

panelists for goat smell was neutal (average value of

2.200 with level/intensity of goat smell being “no

goat smell”. This showed that goat milk

fermentation process into yoghurt with the help of

Lactobacillus bulgaricus, Streptococcus

thermophilus, and Lactobacillus acidophiluswas

able to eliminate characteristic musky smell of goat

milk.

Aroma is related to sense of smell. Aroma

considered to be pleasant comes out of the right

blend of different components. Rice bran has a very

strong and unique aroma. This smell comes from

tocopherol oil in rice bran, which is a very volatile

compound (Inggita et al 2015; Sarbini et al. 2009). If

air containing volatile compound from rice bran

floated in turbulence within the gap of nasal cavity,

upon contact with the tip of olfactory cell, the aroma

could be smelled (Rasbawati et al. 2019). For goat

milk yoghurt fortifiedby white rice bran flour,

panelist preferences assessment for rice bran smell

was neutral (average 2.17) with level/intensity being

“does not smell rice bran” (average value 1.97). This

showed that rice bran flour fortification did not

cause prominent rice bran smell in yoghurt at 4%

concentration, because of the relatively small

concentration of the flour.

6 CONCLUSIONS

Based on the result of this research, addition of

white rice bran flour in 4% concentration into milk

goat yoghurt making process produced yoghurt with

organoleptic characteristics being sour, did not smell

of goat or rice bran, and having medium

consistency/adequate solidity

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