International Journal of Trend in Scientific Research and Development (IJTSRD)

Volume: 3 | Issue: 4 | May-Jun 2019 Available Online: www.ijtsrd.com e-ISSN: 2456 - 6470

Organoleptic Evaluation and Profitability Analysis of

“Yoghurt-Like Product” Manufactured using Tiger Nut
Agwuna, Linus Chukwuma, Okonkwo, Ifeyinwa Felicia, Egbuim, Timothy Chukwudiegwu
Department of Applied Microbiology and Brewing, Faculty of Biosciences,
Nnamdi Azikiwe University, Awka, Anambra, Nigeria

How to cite this paper: Agwuna, Linus ABSTRACT

Chukwuma | Okonkwo, Ifeyinwa Felicia In this study, tiger nut milk was produced using a standard method and
| Egbuim, Timothy Chukwudiegwu employed in yoghurt production. The following investigations were carried out
"Organoleptic Evaluation and on the tiger nut yoghurt produced; microbial analysis by plate count method,
Profitability Analysis of “Yoghurt-Like organoleptic evaluation using 9 point Hedonic scale and profitability analysis by
Product” Manufactured using Tiger Nut" cost per unit volume. The result of total plate counts were 3.5 × 101 cfu/ml, 4.2 ×
Published in International Journal of 101 cfu/ml, 3.7 × 101 cfu/ml and 4.4 × 101 cfu/ml for produced tiger nut yoghurt,
Trend in Scientific Research and Market yoghurt 1, Market yoghurt 2 and Market yoghurt 3, respectively. The
Development (ijtsrd), ISSN: 2456-6470, result of yeast and mould counts were 3.7 × 101 cfu/ml, 4.3 × 101 cfu/ml, 3.8 ×
Volume-3 | Issue-4, 101 cfu/ml and 4.4 × 101 cfu/ml for produced tiger nut yoghurt, Market yoghurt
June 2019, pp.315- 1, Market yoghurt 2 and Market yoghurt 3, respectively. The coliform count
318, URL: showed no growth for all the samples. The results of the mean rating by the
https://www.ijtsrd.c panellists for tiger nut yoghurt were 7.53, 6.80, 6.20, 7.80 and 7.50 for colour,
om/papers/ijtsrd23 taste, smell, mouth-feel and overall acceptability, respectively while the
573.pdf panellists mean rating for commercial yoghurts were 8.05, 6.72, 7.00, 7.40, 7.31
IJTSRD23573 for colour, taste, smell, mouth-feel and overall acceptability, respectively. The
Copyright © 2019 by economic analysis of the study revealed that it costs only N185 to produce 500ml
author(s) and International Journal of of tiger nut yoghurt while commercial yoghurt of the same volume costs N215 on
Trend in Scientific Research and the average.
Development Journal. This is an Open
Access article distributed under the KEYWORDS: Yoghurt, Tiger nut, Organoleptic, Profitability Analysis
terms of the Creative Commons
Attribution License 1. INTRODUCTION
(CC BY 4.0) Yoghurt is a coagulated milk product that results from the fermentation of lactic
(http://creativeco acid in milk by Streptococcus thermophilus and Lactobacillus delbrueckii subsp.
mmons.org/licenses/by/4.0) bulgaricus (Bataway and Khalil, 2018). Fermentation of lactose by these bacteria
produces lactic acid, which acts on milk protein to give yoghurt its textures and
characteristics tang (Sanful, 2009).

Yoghurts come in a variety of textures (liquid, set and stirred Tiger nuts are sweet nut-like vegetable root tubers of the
curd), fat contents (regular fat, low-fat and fat-free) and perennial grass-like cyperaceous plant called Cyperus
flavors (natural, fruit, cereal, chocolate), and can be esculentus L. (Coskuner et al., 2002). The plant thrives in the
consumed as a snack, part of a meal, as sweet or savory food tropical and Mediterranean regions; it’s commonly grown in
(Reeta et al., 2015). The versatility, together with their Nigeria, Ghana, Togo, Ivory Coast, Spain and Egypt where the
acceptance as healthy and nutritious food, has led to their root tubers are mainly used as a source of food nutrients
widespread popularity across all populations (Mckinley, (Pascual et al., 2000). Tiger nuts are rich in carbohydrate,
2005). lipids, fibre, some proteins, minerals, ascorbic acids and α-
tocopherols (Ekeanyanwu and Ononogbu, 2010). To exploit
Vegetable milk is a product of plant origin which presents their nutritional potentials, tiger nuts have recently been
aspects close to the milk of animal origin (Malik et al., 2012). experimented for enriching the fibre content in gluten-free
It has been consumed for centuries in various cultures, both bread and biscuits (Aguilar et al., 2015; Zahra and Ahmed,
as a regular drink (such as the Spanish horchata) and as a 2014). Lactic acid fermentation of tiger nut milk is of
substitute for dairy milk. The most popular varieties are particular interest because of the prospects to generate
soymilk, almond milk, rice milk, coconut milk and tiger nut lactose-free, yoghurt-like products of improved microbial
milk (Ukwuru and Ogbodo, 2011; Sethi et al., 2016). The stability and extended shelf life with acceptable sensory
protein content varies, it contains no lactose or cholesterol properties. Such fermented systems might be promising as a
and is usually sold with added calcium and vitamins valuable alternative source of food nutrients, especially in
especially B12. According to Sethi et al. (2016), there are many developing countries where the population present a
several reasons for choosing cow milk alternatives which high prevalence of lactose intolerance and limited access to
include; cow milk allergy, lactose intolerance, veganism, nutritious food (Vesa et al., 2000).
calorie concern and prevalence of hypercholesterolemia.
Plant milk is used to make plant cream, ice-cream, vegan The continued diary milk shortage or absence in developing
cheese and yoghurt such as tiger nut yoghurt and soy countries has led to the production of milk substitutes from
yoghurt). vegetables. According to Harkins and Sarret (1967), the

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 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470
development of milk substitutes extracted from cereals and Microbiological Analysis
legumes serve as an alternative way of producing acceptable Microbiological analysis was done on the tiger nut yoghurt
nutritious food based on vegetables. Although yoghurts are produced and purchased yoghurt samples to give an
produced in Nigeria, the need for cost-effective major raw indication of their microbial load. 5ml each of the produced
material for yoghurt production as well as lactose-free and market yoghurts were homogenized for 1 min in an
yoghurt-like products cannot be overemphasized. The high electromechanical homogenizer (Stomacher, Lab-blender
cost of cow milk has led to explorations on local substrates 3500, Seward Medical, London, UK). Serial dilutions of the
that will serve as major raw material for yoghurt production. samples were prepared for plating. Plate Count Agar (PCA)
Considering the economic situation of the country, there is a was used for enumeration of total plate count and the plates
need for the adoption of local and cheap materials for were incubated at 37°C for 24 h. Yeast Extract Agar (YEA)
products that are cheaper and readily available for general was used for yeast and mould enumeration; the plates were
consumption. incubated at 25°C for 48 hours, according to Marshall
(1992). Violet Red Bile Agar was used for the enumeration of
2. MATERIALS AND METHODS coliforms and the plates were incubated at 37°C for 24 h,
Sample Collection according to Marshall (1992).
Tiger nut for milk production was purchased from Eke-Awka
market in Awka, Anambra State. Organoleptic Evaluation
The overall acceptability of tiger nut yoghurt manufactured
Starter cultures Streptococcus thermophilus and Lactobacillus was carried out by 20 panellists according to the method
bulgaricus were purchased from Onitsha main market, described by Sameen et al. (2016). Appearance, colour, taste,
Anambra State. smell, mouth-feel and general acceptability ranking were
assessed for organoleptic evaluation; the mean of the
Equipment and Reagents manufactured yoghurt and of three popular market yoghurts
Processing facilities which include homogenizer, water bath, was taken. The organoleptic evaluation was done using 9
Waring blender, refrigerator and other equipment, as well as point Hedonic scale. The ratings were as shown below:
reagents, were provided by the Department of Applied
Microbiology and Brewing, Nnamdi Azikiwe University, Rating Acceptability Score
Awka, Anambra State, Nigeria. Like extremely 9
Like very much 8
Milk Extraction Method Like moderately 7
The extraction of milk (Figure 1) was carried out by the Like slightly 6
modification of the traditional method of milk extraction as Neither like nor dislike 5
described by Ofori-Anti (2000). One kilogram (1kg) of tiger Dislike slightly 4
nut was milled with 2000ml of distilled water in a Waring Dislike moderately 3
blender at high speed for 10 minutes. The milk slurry was Dislike very much 2
pressed through cheesecloth; the milk obtained was fortified Dislike extremely 1
with 2g of glucose and was used for yoghurt production.
Profitability Analysis
Raw Tubers Profitability analysis was carried out to ascertain the cost of
producing a 500ml bottle of the yoghurt and those of some
Washing popular yoghurts of the same quantity in the market.

Soaking The cost of the following was found and recorded:

1. Tiger nut per kilogram
Wet Milling 2. Flavour used (Vanilla) per ml
3. Sucrose sugar per gram
Pressing 4. Cost of water per 2 litres
5. Cost of other inputs used
Cake
The total unit cost of producing 500ml of yoghurt using tiger
Milk nut was compared to the mean cost of three commercial
Figure: 1: Flow Diagram for milk production from yoghurts popular in the market.
tiger nut tubers (Ofori-Anti, 2000).
3. RESULTS
Preparation of Yogurt Microbial Counts of Yoghurt Products
The tiger nut milk was filtered of impurities using Table 1: Aerobic Plate Count-Total Viable Count of the
cheesecloth. The temperature of the milk was gradually Finished Product and Market Yoghurts
increased to 80oC for 60 min to ensure proper Samples Count(s) (Cfu/ml)
pasteurization. Pasteurized tiger nut milk was rapidly cooled
Produced tiger nut yoghurt 3.5 × 101
to 44oC for purpose of starter culture addition; 5g of starter
culture was added and stirred for 4 min. Thereafter, Market yoghurt 1 4.2 × 101
sterilized bottle jar with a tight seal was filled with milk and Market yoghurt 2 3.7 × 101
incubated in a water bath at 44oC for 4 h until complete
coagulation. Manufactured yoghurt was stored in a Market yoghurt 3 4.4 × 101
refrigerator at 5oC as described by Tamime and Robinson
(1985).

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Table 2: Yeast and Mould Counts of the Finished week. The results of the organoleptic evaluation conducted
Product and Market Yoghurts were shown in Table 4 as mean scores ± standard deviation.
Samples Count(s) (Cfu/ml)
Produced tiger nut yoghurt 3.7 × 101 Table 4: Organoleptic Evaluation of Tiger Nut Yoghurt
Market yoghurt 1 4.3 × 101 Produced and Market Yoghurts
Market yoghurt 2 3.8 × 101 Organoleptic Tiger Nut Market Yoghurt
Market yoghurt 3 4.4 × 101 Attributes Yoghurt (1,2and 3)
Colour 7.53b ±0.43 8.05a ± 0.34
Table 3: Coliform Counts of the Finished Product and Taste 6.80a±0.23 6.72a± 0.03
Market Yoghurt Smell 6.20b ±0.03 7.00a± 0.01
Samples Count(s) (Cfu/ml) Mouth-feel 7.80a±0.41 7.40a± 0.34
Produced tiger nut yoghurt 0 Overall acceptability 7.50a±0.33 7.31a± 0.32
Market yoghurt 1 0 Key:
Market yoghurt 2 0 1. Results are means of twenty organoleptic scores ±
Market yoghurt 3 0 Standard deviation
2. Means in the same column with the same superscript
Results of Organoleptic Analysis are not significantly different (p>0.05)
The panellists comprised of 40% women and 60% men,
majorly postgraduate students and staff of Department of Profitability Analysis
Applied Microbiology and Brewing, Nnamdi Azikiwe Table 5 represents the total cost of raw materials purchased
University, Awka. Majority of them reported that they for tiger nut yoghurt production and their unit price per
consume yoghurt at least once in a month and just a few of gram; this was to deduce the quantity and price of the raw
them reported that they consume yoghurt at least once every materials involved in producing 500ml of yoghurt.

Table 5: Prices of Materials for Yoghurt Production

Total Cost Unit Mean price of 3
S/N Material Quantity
for 2 litres price/500ml market yoghurts
1 Tiger nut 1kg N300 N75
Other Ingredients

2 Starter culture (yogourmet) One packet(5g) N300 N75

3 Sugar 2g N20 N5
4 Flavour (vanilla) 5ml N20 N5
5 Water 2 litres N20 N5
6 Packaging container 4 bottles (500ml each) N80 N20
The total amount per 500ml N185 N215

4. Discussion There was a significant difference between the tiger nut

Aerobic plate count is used as an indicator of bacterial yoghurt and commercial yoghurt based on colour (p<0.05).
populations in a food sample (Belewu and Abodunrin, 2006). The rating for Taste followed almost the same trend as it has
The population of bacteria in the yoghurt samples ranged a mean rating score of 6.80 while commercial yoghurt
from 3.5 × 101 to 4.4 × 101. Garbutt (1997) stated that recorded 6.72 which translates to “like moderately”. The
microbial count less than 30 colonies or less than 2.4 x 104 results showed that tiger nut yoghurt can give a good taste of
colony forming units per ml for the viable bacterial count in yoghurts. There was no significant difference between the
a mixed culture is negligible or insignificant in food quality tiger nut yoghurt and commercial yoghurt based on taste
and safety assessment, thus, the tiger nut yoghurts were (p>0.05). The smell of the tiger nut yoghurt was also
suitable for human consumption. The yeast and mould accepted by the panellists as it recorded reasonable high
counts for the samples did not exceed the microbiological mean score of 6.20 which translates to “like slightly”,
counts of 1.0 × 104 cfu/ml (Table 2) indicating that they were although the commercial yoghurt recorded a higher mean
safe for consumption. No coliforms were detected in the score of 7.0 which translate to “like moderately”. There was
samples, which is in accordance with the microbiological a significant difference between the tiger nut yoghurt and
standards (Table 3). This indicates that the samples were commercial yoghurt based on smell (p<0.05).
within acceptable limit hence safe for consumption.
The score for mouth-feel recorded a high score of 7.80 which
The organoleptic scores for tiger nut yoghurt produced in translates to “like very much” compared to commercial
comparison with commercial yoghurts in the market were yoghurt that recorded a mean score of 7.40 which translates
shown in Table 4; all the panellists rated the product to “like moderately” on the 9-point hedonic scale. There was
considerably high in almost all the attributes evaluated. The no significant difference between the tiger nut yoghurt and
result showed that the colour of the produced tiger nut commercial yoghurt based on mouth-feel (p>0.05). On the
yoghurt recorded high mean score of 7.53 which translates general acceptability, tiger nut yoghurt was most preferred
to “like moderately” on the 9-point hedonic scale while as it had the highest mean score of 7.50 translating to “like
commercial yoghurt recorded a mean score of 8.05 which very much” while the commercial yoghurt had the mean
translates to “like very much” on the same scale. The colour score of 7.31 translating to “like moderately”. Many of the
was based on how the appearance appealed to the panellists. panellists after the evaluation declared interest to buy the
product if brought to the market. Results of the profitability

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 International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470
analysis showed that it costs only N185 to produce 500ml of [9] Marshall, T. R. (1992). Standard method for the
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be most appreciated by low-income earners and lactose and Food Science, University of Ghana.
intolerant patients. Also, the product is safe for human
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