INTRODUCTION
India's market potential and current growth rate of traditional dairy products
is unparalleled and all set to boom further under the technology of mass production.
This market is the largest in value after liquid milk and is estimated at US
$3 billion in India and US $1 billion in North America alone (Aneja,
2002). An estimated 50 to 55% of the milk produced in India is converted
into a variety of traditional milk products, using processes such as coagulation
(heat and/or acid), desiccation and fermentation (Aneja, 2002).
Dairy products are likely to remain important dietary components because of
their nutritional value, flavor and texture. There will continue to be a demand
for traditional, high quality dairy products, despite increasing competition
from non-dairy based products (Rathore et al., 2007).
It is envisaged that development of suitable technological package for the organized
production of these products would offer significant value addition and product
diversification for Indian dairy industry.
One of the traditional dairy products of the state of Jammu and Kashmir is Kaladhi. It is an acid coagulated dairy product prepared by directly acidifying milk with some easily available organic acids as coagulating agents and working out coagulum into a pat. Small balls made out of the pat are later given a circular shape of varying diameters. The tribal communities in the upper hilly regions and people of the Jammu division of the state of Jammu and Kashmir refer this product as Kaladhi where as it is known as Maush-Kraer in Kashmir division of the state. The product is prepared either from cow’s or buffalo’s milk or a mixture thereof. The product has a tremendous market potential and is considered a delicacy throughout the state. It is consumed after frying it with some suitable frying medium along with spices and condiments. It is also consumed in the form of culinary dish in combination with vegetables and gravy. Besides being a salubrious food, it is believed to possess antidiarrhoeal, anticold and antitussive properties.
Buttermilk cheeses in Europe, Tibet cheese in Tibet, Chugga or Churpi in Nepal and native paneer are some of the documented products with similarities in characteristics and utilization. The product has immense popularity and public acceptance within the state. It is commonly available at most of the renowned food junctions with great potential of being taken as a commercial venture. Thus, it may become a promising alternative to paneer particularly in areas with inadequate preservation facilities.
The typical acid flavor and preparation procedure differentiate Kaladhi from similar coagulated milk products. Kaladhi, like paneer, does not require the use of rennet or starters during its preparation. It is rather prepared by coagulating milk using various organic acids and has a remarkable shelf life owing to its high ultimate acidity. The most popular coagulant used traditionally for the preparation of Kaladhi is tartaric acid. Other methods of Kaladhi preparation either use citric acid or stored whey to bring about coagulation of either raw or boiled milk. It is mostly prepared as a cottage enterprise with hardly any control over the quality. The technological variations and the quality of milk determining the characteristics of the final product lead to the wide differences in the product yield and quality characteristics. Moreover, the addition of different acid coagulants in varying concentrations results in a non-uniform product quality and yield which is of paramount importance.
The traditional dairy products provide an excellent opportunity for value-added
dairy foods and represent an untapped potential for growth in domestic as well
as international market. Despite their increasing popularity and potential economic
significance, traditional dairy foods are largely produced by small-scale processors
employing age-old methods of processing, handling, storage and distribution,
which limit the quality and shelf life of the products (Vasavada,
2007).
Traditional Indian dairy products like other traditional foods need attention with regard to technology development. Hence, if traditional foods are proposed to be marketed on commercial scales, it becomes imperative that suitable technologies be developed for their production and packaging. Technology of traditional foods is also relevant to institutional food systems, catering services and cross-continental marketing necessitated by presence of large ethnic groups in foreign countries. While the sensory character continues to linger in the minds of the people, the old technology fast becomes unattractive in the modern manufacturing and marketing context. This is where continued interest in research on the traditional products is generally focused.
Scenario of cheese production in India is quite bright because of the facts
that cheese has all the beneficial attributes of an ideal dairy product and
the emergence of new global economic reforms based on globalization and liberalization
in the marketing arena that has unfastened the door to the Indian dairy industry
to penetrate the international cheese market (Kanawjia,
2007). Technologies have been appropriately standardized for manufacture
of various types of cheeses. Cheese and a wide variety at that have evolved
to such an extent that most cheese is produced employing modern technology and
traditional technologies have largely been replaced by modern manufacturing
practices.
The yield, composition and quality characteristics of cheese depend upon various
factors like technological variations and the quality of milk (Abd
El-Aziz et al., 2007; El-Diam and El-Zubeir,
2006). Absence of standard processing methods explains the variations in
cheese quality and physicochemical characteristics (Turkoglu
et al., 2003; Alalade and Adeneye, 2007).
The method of manufacture of Kalladhi is traditional, primitive and more or
less limited and offers a great scope for development. The efforts are needed
to be directed towards modernizing the processing parameters on the scientific
lines with respect to the raw material use, processing techniques, end product
characteristics, preservation and value addition. In lieu of these facts and
lack of scientific reports on the same, an attempt was made to study the shelf
life of Kaladhi prepared from buffalo milk using three different organic acid
coagulants at their optimum level viz., 5% acetic acid, 5% citric acid and 5%
lactic acid with a view to develop this dairy product with most suitable and
desirable characteristics.
MATERIALS AND METHODS
Source of milk: Fresh buffalo milk from the local market of Jammu was used in all experiments after suitable standardization as per the Pearson square method. Based on the result of the preliminary trials, the fat percentage of milk was standardized to 5.5% fat with 9% SNF for optimum product characteristics. Thereafter, standardized milk was pasteurized and each batch of Kaladhi was prepared from 10 kg of milk.
Acid coagulants: Three organic acid coagulants were used for coagulating the standardized milk for the preparation of Kaladhi viz., citric acid, acetic acid and lactic acid at three different concentrations i.e., 5, 7.5 and 10%. Based on the preliminary trials, strengths of the different organic acids used for the preparation of Kaladhi were optimized viz., 5% acetic acid, 5% citric acid and 5% lactic acid for the preparation of the product with a view to develop this dairy product with most desirable product quality characteristics.
Chemicals and media: All the chemicals and media used were of analytical grade and were obtained from standard firms (Qualigens, C.D.H, Hi Media etc.) from the suppliers in the local market of Jammu.
Preparation of Kaladhi: Preliminary trials were conducted for different coagulation temperatures to achieve the desired physicochemical and sensory characteristics of the product. Based on those preliminary trials, fresh buffalo milk standardized to 5.5% fat and 9% SNF with coagulation at 40°C incorporated the desired characteristics. Traditionally the milk is also coagulated at the same temperature to obtain the quality product.
The milk was pasteurized and cooled to 40°C, followed by coagulation at this temperature with optimum levels of different organic acids (5% acetic acid, 5% citric acid and 5% lactic acid) till the attainment of a uniform curd. The curd was immediately drained through muslin cloth without pressing. The curd was then opened, molded into pieces of convenient size and placed in petri plates of uniform size used as moulds. The curd was then taken out of the moulds and allowed to dry at room temperature in bamboo baskets. Regular turning of the product after 5 h interval was ensured for at least 3 days until sufficient moisture was lost through evaporation. The product was allowed to dry in a clean and moisture free environment abstaining from direct sun drying.
Analytical procedures
pH: The pH of Kaladhi was determined as per the method of O’Keeffe
et al. (1976) by using a digital pH meter (Systronics Digital pH
Meter 802, Serial No. 603).
Proximate composition: The moisture, crude protein, ether extract (on
dry matter basis) and ash content of Kaladhi were determined by standard methods
using hot air oven (Yorco sales Pvt. Ltd. India, Model-YS1-431, S. No. 02B2843),
Soxhlet extraction apparatus, Muffle furnace and Kjeldhal assembly, respectively
(AOAC, 1995).
Yield: The weight of each Kaladhi was recorded and the yield was calculated and expressed as percentage by a formula:
Thio Barbituric Acid (TBA) value: Thiobarbituric acid value of Kaladhi,
during storage was determined using the method of Witte
et al. (1970).
Free fatty acids: The method suggested by Koniecko
(1979) was followed to measure the free fatty acids in Kaladhi samples.
Titratable acidity: The method as described by AOAC
(1995) for cheese was followed to determine the titratable acidity in Kaladhi.
Microbiological profile: Total plate count, yeast and mould count and
coliform count in the samples were determined by method described by Marshall
(1993) using vertical laminar flow (Thermo Electron Corporation. D-63505
Langenselbold, Robert Boschstr. 1, Germany). Readymade media procured from Hi-Media
Laboratories Pvt. Ltd., Mumbai (Code No. M091) from local suppliers were used
for the analysis.
Sensory evaluation: The sensory evaluation of the product was carried
for attributes, namely appearance, flavour, juiciness, sourness, texture and
the overall acceptability of fresh and stored samples by a panel of trained
members composed of scientists and research scholars of the division based on
a 8-point hedonic scale, wherein 8 denoted extremely desirable and 1 denoted
extremely undesirable (Seman et al., 1987). The
panels were trained for four basic tastes, i.e., recognition and threshold test
and hedonic tests routinely performed in the division. Panelists were seated
in a room free of noise and odours and suitably illuminated. Coded samples for
sensory evaluation were prepared by shallow frying of Kaladhi in oil and served
warm to panelists. Water was provided for oral rinsing between the samples.
Statistical analysis: The data obtained were subjected to statistical
analysis for analysis of variance, critical difference and Duncan’s multiple
range tests for comparing the means to find the effects between treatments and
storage periods for various parameters in different experiments at a 5% significant
level and data were analyzed on a computer using statistical software packages
developed by following the procedures of Snedecor and Cochran
(1989). There were seven sensory judges for each treatments x replication
combination.
RESULTS AND DISCUSSION
Physicochemical parameters: The mean values of various physicochemical characteristics of Kaladhi at different storage periods are presented in Table 1.
pH: A significantly (p<0.05) decreasing effect of storage on pH values
of Kaladhi prepared from various organic acid coagulants was observed. The values
of pH for Kaladhi prepared from control at 0 day of storage were significantly
(p<0.05) different from 14th day as well as 28th day of storage. A similar
trend was followed by Kaladhi prepared from 5% acetic acid. However, in both
treatments, the values for pH remained relatively stable from 14th day of storage
onwards. A significant (p<0.05) difference in the values for pH was observed
throughout the storage period for Kaladhi prepared from 5% citric acid and 5%
lactic acid and in general, highest values for pH were reported on 0 day of
storage. Similar findings were reported by Pal and Garg
(1989), Kumar and Bector (1991) and Pal
et al. (1993) in paneer. Alalade and Adeneye
(2007) also reported a decreasing effect of storage on pH values of Wara
Cheese under frozen storage.
| Table 1: |
Effect of ambient storage (21-25°C) on physicochemical
characteristics of Kaladhi prepared with different organic acid coagulants |
 |
| Mean±SE with different superscripts in a row wise (small
alphabet) and column wise (capital alphabet) differ significantly (p<0.05),
n = 3 for each treatment |
The pH values in Kaladhi were lower than paneer probably because the acid used for coagulation in the present study furnished a higher hydrogen-ion concentration in the final product. Further, the amount of acid used for coagulation of milk for Kaladhi preparation is more than that used in paneer preparation because of lower temperature of coagulation (40°C).
Titratable acidity: The values of titratable acidity for Kaladhi prepared
from control at 0 day of storage were significantly (p<0.05) different from
14th day as well as 28th day of storage. However, titratable acidity values
for all other coagulants used showed non-significant (p>0.05) difference
from 14th day of storage onwards. A significant (p<0.05) difference in the
values for titratable acidity was also observed throughout the storage period
for Kaladhi prepared from 5% lactic acid. Similar findings were reported by
Pal and Garg (1989), Kumar and Bector
(1991) and Pal et al. (1993) in paneer.
Free fatty acids (% Oleic acid): The difference between the values of
free fatty acids for Kaladhi prepared from all types of coagulants throughout
the storage period were non-significant (p>0.05). However, free fatty acid
values for Kaladhi prepared from 5% citric acid at 0 day showed significant
(p<0.05) difference when compared with 28th day of storage. Irrespective
of the type of coagulant used, the difference between values of free fatty acids
for all coagulants used for product preparation were non-significant (p>0.05)
at 28th day of storage when compared with each other. Similar trends were reported
by Pal and Garg (1989), Kumar and
Bector (1991) and Pal et al. (1993) in paneer.
Thiobarbituric acid value (mg malonaldehyde/Kg): The difference between the thiobarbituric acid values for Kaladhi prepared from all types of coagulants was significant (p<0.05) throughout the storage period. However, thiobarbituric acid values for Kaladhi prepared from all coagulants at 0 day showed significantly (p<0.05) lower values when compared with 14th day and 28th day of storage. A non-significant (p>0.05) difference was also observed between the individual values of thiobarbituric acid for control and 5% acetic acid throughout the storage period.
These findings could be supported by the fact that the product was exposed
to spoilage causing micro-organisms since it was stored at temperatures most
suitable for the growth of such invasive microorganisms. Therefore, all the
changes during storage reported in the present study were probably due to the
growth of spoilage organisms. Similar findings were reported by a number of
other workers in paneer as well Pal and Garg (1989),
Kumar and Bector (1991) and Pal
et al. (1993).
Proximate composition: Mean proximate values of Kaladhi at ambient storage are presented in Table 2. A significant (p<0.05) decrease in the moisture and ether extract content of the product was observed with an increase in the period of storage, while the crude protein content values dropped rather slowly. However, the ash content of Kaladhi prepared from various organic acids proved to increase non-significantly (p>0.05) with increase in the storage period.
Moisture: The difference between the moisture content of Kaladhi prepared
from control and 5% acetic acid was significant (p<0.05) upto 14th day of
storage However, a non-significant (p>0.05) difference in the values of protein
content for Kaladhi prepared from 5% citric acid and 5% lactic acid was observed
throughout the storage period.
| Table 2: |
Effect of ambient storage (21-25°C) on proximate composition
of Kaladhi prepared with different organic acid coagulants |
 |
| Mean±SE with different superscripts in a row wise (small
alphabet) and column wise (capital alphabet) differ significantly (p<0.05),
n = 3 for each treatment |
In general, a non-significant (p>0.05) decrease in the moisture content
of Kaladhi prepared from various organic acids was observed from 0 day to 28th
day of storage. The decrease in moisture content over the storage period might
be due to loss of some amount of moisture by evaporation as the product was
exposed to open ambient environment. Similar trends were also reported by Sanyal
et al. (2006), Rao et al. (1984) and
Arora and Gupta (1980) in paneer.
Crude protein: The difference between the crude protein content of Kaladhi
prepared from all types of coagulants was significant (p<0.05) throughout
the storage period except for Kaladhi prepared from 5% acetic acid and 5% lactic
acid which showed a non-significant (p>0.05) change from 0 day to 28th day
of storage. However, significantly (p<0.05) lower values of protein content
for control were observed between treatments of all types of coagulants used
to prepare Kaladhi throughout the storage period when compared with each other.
The decrease in the protein content during the period of storage can be attributed
to high microbial load in the product which might have caused proteolysis to
a greater extent. Similar findings were also reported by Sanyal
et al. (2006), Rao et al. (1984) and
Arora and Gupta (1980) in paneer. Kilic
et al. (2004) also reported a similar decrease in protein content
of Turkish fresh goat cheese during storage.
Ether extract (on dry matter basis): The difference between the ether
extract content of Kaladhi prepared from all types of coagulants was significant
(p<0.05) throughout the storage period except for control which showed a
non-significant (p>0.05) difference in the values during the period of storage
from 0 day to 28th day. However, significantly (p<0.05) lower values of ether
extract for 5% lactic acid were observed between treatments of all types of
coagulants used to prepare Kaladhi throughout the storage period. Decrease in
the ether extract values of the product stored at ambient temperature might
be a result of depletion of fat globules during storage. Similar findings were
also reported by Sanyal et al. (2006), Rao
et al. (1984) and Arora and Gupta (1980)
in paneer.
Ash: The difference between the ash content of Kaladhi prepared from
all types of coagulants was non-significant (p>0.05) throughout the storage
period. However, significantly (p<0.05) lower values of ash content for control
were observed between treatments of all types of coagulants used to prepare
Kaladhi throughout the storage period when compared with each other. Similar
trends were reported by Sanyal et al. (2006),
Rao et al. (1984), Arora
and Gupta (1980) in paneer.
Microbiological characters: The mean values of various microbiological characteristics of Kaladhi are presented in Table 3. In general, total plate count, coliform count and yeast and mold count, all were found to increase significantly during the storage period.
Total plate count (log cfu g-1) A significant (p<0.05) effect of storage was observed on total plate count of Kaladhi prepared from various organic acid coagulants. The total plate count was also found significantly (p<0.01) different between various types of coagulants used for product preparation. Irrespective of the days of storage, Kaladhi prepared from 5% lactic acid had significantly (p<0.05) lower counts than that of all other coagulants used for product preparation. It was seen that both in case of control as well as Kaladhi prepared from various organic acids, the counts continued to increase with the increase in storage period. Regardless of the treatment, 28th day counts were significantly (p<0.05) higher than 0th day counts, which in turn were significantly (p<0.05) lower than 14th day counts for Kaladhi prepared from 5% acetic acid.
The increase in total plate count in the present study might be a result of
growth of micro-organisms at ambient temperature and the subsequent decrease
in pH values during the storage period which might have aided in providing an
optimum growth environment. Similar findings have been reported by Sachdeva
et al. (1985), Sanyal et al. (2006),
Kumar and Bector (1991) and Pal
et al. (1993) in paneer.
| Table 3: |
Effect of ambient storage (21-25°C) on microbial characteristics
of Kaladhi prepared with different organic acid coagulants |
 |
| Mean±SE with different superscripts in a row wise (small
alphabet) and column wise (capital alphabet) differ significantly (p<0.05),
n = 6 for each treatment |
Yeast and mold count (log cfu g-1): A significant (p<0.05) effect of storage on yeast and mold count of Kaladhi prepared from various organic acid coagulants was observed. A highly significant (p<0.01) effect of treatments (types of coagulants used for product preparation) was also found. The yeast and mold counts were reported maximum in Kaladhi prepared from 5% lactic acid owing to its low pH and high moisture content. Both control as well as the Kaladhi prepared from various organic acids showed a continuous increase in counts with the increase in storage period. Counts at 28th day were significantly (p<0.05) higher than 0th day counts for Kaladhi prepared from 5% citric acid and 5% lactic acid, which in turn were significantly (p<0.05) lower than 14th day counts for Kaladhi prepared from the same coagulants. Regardless of the storage period, a non-significant (p>0.05) effect was observed as far as yeast and mold counts is concerned for Kaladhi prepared from control and 5% lactic acid.
The subsequent decrease in pH values during the storage period might have aided
in providing an optimum growth environment for yeast and mold. Thus, optimum
pH and moisture content might be the cause of increased yeast and mold count
in the product during the storage period. Similar trends have been reported
by Sachdeva et al. (1985), Sanyal
et al. (2006), Kumar and Bector (1991) and
Pal et al. (1993) in paneer. El-Diam
and El-Zubeir (2006) also reported a significant (p<0.05) increase in
yeast and mold counts of processed Sudanese white cheese during storage.
Sensory parameters: Mean sensory scores of Kaladhi during storage at ambient temperature are presented in Table 4. All the sensory parameters namely appearance, flavour, juiciness, texture, sourness and overall acceptability of the Kaladhi showed significant (p<0.05) decline during the storage period. These changes are sequel to factors such as the loss of moisture, change in color, change in functional properties of proteins and fats and an increase in microbial count of the product during the storage period.
The mean scores of Kaladhi for appearance at 0 day of storage were significantly
(p<0.05) higher than 14th and 28th day of storage. However, the scores of
Kaladhi prepared from 5% acetic acid and control were comparable from 14th day
onwards. Kaladhi prepared 5% lactic acid showed a significantly (p<0.05)
higher scores for appearance than the Kaladhi prepared from 5% citric acid throughout
the period of storage. Similar results were reported by Arora
and Gupta (1980) and Sanyal et al. (2006)
in paneer.
The mean flavor scores of Kaladhi prepared from 5% acetic acid and 5% lactic
acid showed a significant (p<0.05) decrease throughout the storage period
whereas control and 5% citric acid showed comparable (p>0.05) scores upto
14th day of storage. However, significantly (p<0.05) lower flavor scores
at 28th day of storage was observed for Kaladhi prepared from 5% acetic acid
and 5% lactic acid. Arora and Gupta (1980) and Sanyal
et al. (2006) also reported similar decrease in flavour scores with
storage in paneer. Foda et al. (2008) also observed
a decreasing trend in flavor scores with storage in white herby cheese.
A significantly (p<0.05) decreasing trend of the texture scores of Kaladhi
prepared from 5% acetic acid and 5% lactic acid was observed throughout the
storage period. However, control showed comparable (p>0.05) texture scores
upto 14tth day of storage whereas texture scores for 5% citric acid were stable
from 14th day of storage onwards. In general, significantly (p<0.05) lower
texture scores were observed for Kaladhi prepared from all types of coagulants
at 28th day of storage. Similar trend for texture scores were reported by Arora
and Gupta (1980) and Sanyal et al. (2006)
during storage studies of paneer. Foda et al. (2008)
also observed a decreasing trend in texture scores with storage in white herby
cheese.
| Table 4: |
Effect of ambient storage (21-25°C) on sensory attributes
of Kaladhi prepared with different organic acid coagulants |
 |
| Mean±SE with different superscripts in a row wise (small
alphabet) and column wise (capital alphabets) differ significantly (p<0.05),
n = 21 for each treatment |
The juiciness scores of Kaladhi prepared from 5% acetic acid and 5% lactic
acid decreased significantly (p<0.05) throughout the storage period except
for 5% citric acid which showed comparable scores upto 14th day of storage.
Juiciness scores for control showed a non-significant (p>0.05) decrease from
14th day of storage onwards. Irrespective of the type of coagulant used for
preparing Kaladhi, significantly (p<0.05) lower juiciness scores at 28th
day of storage were observed. Arora and Gupta (1980)
and Sanyal et al. (2006) also observed similar
decrease in juiciness scores of paneer during storage.
The sourness scores of Kaladhi prepared from 5% citric acid and 5% lactic acid
decreased significantly (p<0.05) throughout the storage period. However,
sourness scores for control and 5% acetic acid at 0 day of storage were comparable
to scores on 14th day which were comparable to the scores of sourness on 28th
day of storage. Scores for Kaladhi prepared from 5% lactic acid were significantly
(p<0.05) higher among all treatments throughout the period of storage. In
general, sourness scores for Kaladhi prepared from 5% acetic acid and 5% lactic
acid were significantly (p<0.05) lower at 28th day of storage. However, the
sourness scores remained relatively stable from 14th day of storage onwards
in Kaladhi prepared from control and 5% citric acid. Similar trend was reported
by Arora and Gupta (1980) and Sanyal
et al. (2006) during storage studies of paneer.
The overall acceptability scores of Kaladhi prepared from 5% acetic acid and
5% lactic acid showed significant (p<0.05) decline throughout the storage
period. In general, overall acceptability scores for Kaladhi prepared from 5%
acetic acid and 5% lactic acid were significantly (p<0.05) lower at 28th
day of storage. However, the scores for overall acceptability remained relatively
stable from 14th day of storage for Kaladhi prepared from control and 5% citric
acid. Relatively lower overall acceptability scores for Kaladhi prepared from
5% citric acid were due to lower scores for other sensory attributes. However,
overall acceptability scores for control and 5% lactic acid at 0 day of storage
were significantly (p<0.05) lower from 14th day and 28th day of storage.
Overall acceptability scores for Kaladhi prepared from 5% lactic acid were significantly
(p<0.05) higher among all treatments throughout the period of storage. Thus,
on the basis of analysis of different physicochemical and sensory parameters,
lactic acid at 5% level proved to be optimum in the preparation of Kaladhi.
CONCLUSIONS
Processing technology for the preparation of Kaladhi was standardized. The Kaladhi prepared from various organic acids got acceptable scores for various physicochemical properties and sensory scores. On the basis of analysis of different physicochemical and sensory parameters, lactic acid at 5% level proved to be optimum in the preparation of Kaladhi from buffalo milk at 40°C because it imparted the maximum desired characteristics in the product. The microbial profile of the product namely total plate count and yeast and mold count, all were in the acceptable limits for at least 14 days of ambient temperature. The sensory scores for Kaladhi were most acceptable upto 14 days of ambient storage.
