Jt,;fUQII J. Dei/'f}' Sci., 38, 2, 1985

INFLUENCE OF HOMOGENrZA nON OF MILK ON THE QUALITY OF CHAKKA AND SHRfKHAND

H.K. DESAI, S.H . VYAS and K.O. UPADHYAY

• Deparltllelll of Dairy Techl/ology, Sheth M.e. Coffege of Dairy' Sciellce, Gujaral

Agricultural University, Anand Campus, Ancl/ld-J88 IJO

(Rocoived: 30lh April 1984)

INTRODUCTION

Shrikhand is derived from milk after fecmen­Ultion, cutting, draining of whey and addition of sugar alid. Havour. This is a very popular .11nlduct in Western part of India. Recently, 1:~w dairy plants have taken up th~ manufacture or this product. Commercial production of ";hrikhand has been facilitated by the develop­mept of a. semi-mecbanised process (Aneja :lit a/., 1977) . . This in turn has led to improve­'l11~nt in its quality and enhanced popularity rDitong the consumers.

Use of Skim milk for dahi making was 1;uggested by Upadhyay and Dave (1977) and widely practiced for Shrikhand making. This is mainly because of higher fat losses that occur ill wbey when wholemilk dahi is used for Shci­khand making. However, Chakka made from S'Jdm milk is relatively rough and lacks charac­@:istic aroma. In contrast, Chalcka obtained from wholemilk is much superior in both ·CQnsistencyand aroma (Upadhyay and Dave, .1977). The limitation of high fat loss in whey can .be overcome by homogenization of milk, with

.; 'possible additional beneficial effects on quality of Shrikhandas this process has been known to :iinprove the quality of fermented products like

" Xtighurt (Rasie and Kurmann, 1978). However, no published information is available on the elteets of homogenization of milk on the quality of Chakka a~d Shrikhand. The present study

recovery of milk constituents of Chakk:a and the physical, chemica! and organoleptic quality of Chakka and Shrikhand .

J\.lATERlAL AND METHODS

In aU 18 batches (nine for each treatment) of Shrikhand were prepared u,ing st;md;lrdized buffalo, milk (4 % fat) with or without homo­genization as per the method outlined. below:

(a) Processing of milk and formation of curd: For each batch, 25 kg of standardized buffalo milk containing 4 per cent fat and 9.8 to 10.0% solids· not-fat was prepared from fresh buffalo wholemilk containing about 7 to 8% fat and 9.8 to 10.0% solids-nat-fat. Homogenization of standardized milk was carried out at 100 kg/cm 2 pressure at 6O·65'C, using 'Rannie' single stage homogenizer. Both, homogenized and unhomogenized lots of milk were heated to 90'C for 5 min and than cooled to i~ubation temperature of 42 to 43°C.

The processed milks (25 kg each) were in­oculated witb acti"e. cultures of Streptococcus thermophilus and Lactobacillus bulgaricus added, in I: I proportion (obtained from N.D.R.I., Kamal), at the rate of 5% per cent (v/w) of milk. Milk was incubated at 42 to 43dC in a thermostatically controlled room, uiltil the desired acidity of 1.1 to 1.2% was obtained in the curd .

wAs planned- to evaluate the effects of homo- (b) Draining of whey: The curd was converted geni7.lltion of milk on the yield of Chakka; into Chakka by partial removal of whey, using

102

H.K. Desai I!t af.

a batch type vacuum whey drainer which .on­sisted oCa shallow perforated pan (capable 0 r holding .about 10-12 kg curd) lined on the peri­phery wiUJ rubber pad to make air right joint when fixed on the top of a whey collecting vessel which WI!S provided with a drain cock, vacuum guage and a connection to which vacuum pump was connected. The curd was evenly spread on shallmliperforated pan of the vacuum drainer which Was lined with four folds of muslin cloth. The draining was continued al 370-400 mm Hg vacuum until the desired consistency was achieved. Fa r completing one batch of 25 kg two such. vacuum drainers were simultaneouly used. The total time per batch spent in obtain­i ng ChliHa ranged between 50-60 min.

(c) MiXing chakka \l'itll sugar: Chakka was knead¢d over a clean and sanitised stainless steel wfrenesh screen (30 mesh) to obtain uni­form consistency and the n mixed with fine quality crystalline sugar, at the rate of 80 ~Ic:

by weight of Chakka. Chakka with sugar was allowed to stand for 30 min to ensure proper dissolution of sugar and then manually stirred to make the content homogenous. Manual kneading and mixing was kept as similar as possible for aU lots of Shrikhand. No flavour­ing of any kind was added to the product. The lots of Shrikhand were cooled to temperature of ::s '10·C.

CompO'sltional analyses

The' 'representati ve samples of standardized milk" Chakka, whey and Shrikhand were subjec­ted to following analyses as per the procedure stated therein:

(;) Mqistureftotal solids: The total solids conteht of milk and whey and moisture content of Chakka and Shrikhand were detennined by Mojonnier milk tester Model-D, as per stan­dardprocedure (laboratory Manual, 3rd ed., 1959).

(ii) Fat; The fat COrltents in milk, whey and Chakka were determined as per I.S.I . procedures (IS: 1224 ! & H, 1977), whereas of Shrikhand, by Mojonnier method with slight modilicati()" as under:

A known weight of sample (aboiJt 3 g) was digested in a small beaker by additioll of 5,(1 ml of liquid .ammonia (Sp. gr. 1}.91). The. pred,gested sample along\~ith rinsings was then transferred to the fat extraction lIask and f:n. content determined oy the usual pTOced)!r.e (Laboratory Manual, 3rd ed, 1959).

(iii) Protein : Milk, whey, Chakka and Shrikhal1(1 sample, were anaLysed for protein contents a~ '

per lSI procedures (lS:1479-II, 1961; TS :95J2i 1980).

(jr) Sucrose: The sugar content WIIS determin¢d colorimelricaUy as per the method described hy Pantulu 121 01. (1976) for estimation of sucri;ise in ice-cream .

(r) Acidity: The per cent lactic acid of milk. Chakka. whey and Shrikhand were. estimatedi

using lSI procedure, (IS: 1479 I & 11, 1961; ' IS:9532: 1980).

Sensory evaluation

The samples of fresh Chakka and ShrikhaUd (after cooling to :sIO"q were subjected to organoleptic evaluation by a panel of 6 judges selected on the basis of duo-trio test performed for their judging aoility, reliability ar.d re­producibility. The distinquishing features: of Chakka were noted as comments on theorgano­leptie quality of Chakka. For judging Shri­khand the following score card was used:

Parameter Colour Body & Tex.tu re Flavour

Total

Perfect score' 3 S

10 --'

18

104 Quality of Chakka and Shrikhand

,Verisurement of consistency: Consistency of Shrikhand was evaluated in terms of penetro, meter reading immediately after manufacture at 30·C (without cooling) and after cooling for 24 hr at ;:s;10·C. Penetrometer readings for Shrikhand samples were taken using AI MIL cone ~netrometer model FPNJ as per proce· dure described for cream cheese by Hartman ( 1976).

RESULTS AND DISCUSSION

Chakka is the base' material for Shiikhand making and its chemical composition·, acidity. body. texture and flavour greatly inflgence quality attributes of Shrikhalld. AU the Chakkil samples had pleasing aroma.. This cpuld be attributed to the presence of fa.t and its break down products (e.g., Volatile fatty acids) as

TABLE I

Effect of'hDIlI"genization of milk on the yield and' tecm'ory or milk co •• tltutents In Ch"H"

Per cent n:co"oery of Milk

~,:, yierd Fa, Prolejn

Unhomogenized 32.41 90.89 93 .04 Iiomogcnized 33.95 93.41 9!.91

S.Em. 0.883 0 .997 0.881 C.D. at 0.05 NS NS NS

C .V. % 8 ,0} 3.25 2.85 . i "

TABLE 2

A,·cr.lge composition of Chukka and Shrikl"md os .ff«ted by bomo~onlutio.

Milk

Chakka

oVn~omog.ni z<:d

HOl'Qogc:nizcd S,Em. C.D. at 0.05

SiJrikhand

Onhomogeniz.ed Homogenized

S •. Em. e.D. at 0.05

C.V% Chakka Shrikhand

----------------------------------~ Moisture

7l. 3J 71.02 0.593 NS

38.07 38. 16 0.432 NS

2.50 3.43

Fat Protein - - - --- - - ---_._- ---

11.49 l1.77 0.245 NS

6.07 6.39 0.162 NS

6.33 7.81

12.88 12.26 0.258 NS

6.73 6.69 0.158 NS

6.l7 7.06

Sucrose

41.32 42.37 0.355

NS

2.$7

Tota!· Wli'd,

.65.52 68 .• 00 2.2J. NS

.0.93

1 .. 12 2.'08

. Mia 1'iS

1.14'. 1 .. t3 0.012 oNS ...

4.7i1 :Q7 '

,

H.K. Desai el 01. 105

well as other aroma eompounds which could haVe been produced during curd fonnation. Contribution of fat to fineness of flavour of ChaKka has been reported by Upadhyay and Daile. (1977). Homogenization of milk resulted in an increase of 1.5% yield of Chakka and improved the fat recovery by 2.51 %, although it resulted in lower protein recovery in Chilla (bYl.21%). However, these differences in yield and ·recovery of fat, protein as well as total solids between homogenized and unhomogenized mil.ks were non-significant (Table I).

'Homogenization had no adverse effect on the composition of both the products and all the components except moisture in Chakka were well within the lSI specifications for Chakka and Shtikhand (Table 2). Compositional data on Chakka are in agreement with the results of, Sharma and Zariwala (1978), whereas those for- Shrikband are in conformity with the results reponed by Upadhyay (1974); Upadhyay el al. (1975}; Aneja et al. (1977); Upadhyay (J 98 I) and M iyani (1982).

The mean ~ne(ralion values as depicted in Table 3 show decrease in the ~ne(rometer readings upon storage of Sbrikhand at lower temperature, both for homogenized as well as'unhomogenizcd samples implying improve­ment in the consistency. This could be attri-

TABLE 3

ConsistcDC'~' of sllr'ikhamJas infiuenC"t'd bs tlOmogenization .. rmil~

Milk

" . . Unllomoeenised HI'1llogenized

S,Em. C.D. al 0.05

C.Y. %

Penetrometer read ing (mm)

Fresh al JO°C Stored al wOe

36.30 39.10 0.378 1.I9

3,00

24.67 29.23 0.892 2.81

9.93 ---- -------

buted to increase in viscosity of the prodtlCton storage at low temperature. Such increase in consistency of Shrikhand at loWer temperature of storage has been reported by Miyani (jj82). The data in Table 4 further reveal tbatlX>)rIQ­genization of milk had significant effeCt oil the

TABLE 4

Organoleptic quality or fresh s/lrikhand .. -

Flavour Body & lex- 10larsenc Milk score ture score 'S'OrjI'$core

(max. 10) (mai<. 5) (max. j~) ~

UnhomogenizcG 7.96 3.72 14.~~ Homogenized 8.68 4.22 15.90:

S.Em. 0.217 0.128 0:29Q CD. at 0.05 0.68 QAO Q;91

-------C.V. ~o 8.03 9.66 ~,TI

consistency of fresh as well as stored Shrlklland sampl~s. Penetration values for Shrikhand :pre­pared fTOm homogenized milk, both before"nna after storage, were always hj~lier than uri­homogenized milk. This indicates that froJ:!1o­genization of milk caused a decrease 'Iii the firmness of Shrikhand which could be attributed to weak curd formation in homogenized' milk 53mp1es resulting in a product with smooili consistency. However, this decrease in fi'rmness had no adverse effect on the sensory qui!ity of Shrikhand. On the contrary, homogeni;?:ed 'ri,ilk Shrikhand samples were judged signijicantJy better than unhomogenized ones on account of their smoother consistency. Homogenization of milk significantly improved the flavour, l;!6dy and texture score and thus Ihe total. .score (Table 4).

SUMMARY I:.

Homogenization of .milk was found tQ improve the appearance, consistency and' tex­ture of Chakka as compared With urihomoge­nized milk samples. This treatment .aHO.gave

Quality of Chakka and Shrikhand

slightly higher yield (33.95%) and higher fat recovery (93.41%) as compared with 32.41 % and 90.89% respectively for unhomogeni~ed

samples. The fresh samples of Shrikhand, pre­pared from homogenized milk. had significantly hlgber score 8.68, 4.22 and 15.90 for flavour, b.ody and textu rc and total sensory score res­pectively out of a maximum of 10, 5 and 18. In C9ntrast, unbomogenized milk samples scored 7.96, 3.72 and 14.32 respectively fonhe ~!iroe attributes. This superiority in the case of former samples was due to their smoother !:lody and texture and improved flavour. Use of homogenized milk is recommended for Improving organoleptic quality and yield of Shrikhand.

REFERENCES

Anoja, R.P .• Vyas, M.N .• Nanda, K. and Thureja. V.K. (1977) J. Fd. Sci. Tech .• 14(01), t 59.

. H:mman. a.H. (1976) Cllllllmi Dairy Pr()d. I., 11(10). 20,28.

(niliiln Slandard, IS:1479, Part· I (1961) Mtllu;xJs of ·resl for Dairy I"dustry. Rapid ExaminatiQn of Milk rndian Standards Tn"itution. Now Delhi.

Indian Standard, JS;1224, (J977) De/erminatiOlt of !at by Ihe G.,ber method. PaTl-f. Milk. Indian Standards Institution. New Delhi.

Ind ian S tandard , IS: 1224, (19771 neler/llll/arioJ/I of fat by Cerber ",. r!rod. Par/-ll. Milk Prodllcl., . India n Standards rnstitulion, New Dellii.

Indian Standard, IS:9532 (1980) Spec[fo.·dlioJl for Chakka and Shrikhand. Ind,an Standards, ,Inl litu· tion, New Delhi,

Methods of Analysis or mill:: ahd its prQduc'tS'. " Lab\>T3' tory Manu.I," Third Edition (1959). Milk Industry Foundation. Washington, USA, 264. 2S6.

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Sharma, V.P. and Zariwala. I.T. (1978) J. Fd. Sri. Tech., 15(3), 11$.

Upadhyay, K.G. (1974) M.S~. t~csis.GuJ"rii l Ai\C;· cuLtural Unhrerstty.

Upadhy.y. S.M. (1981) M.Sc. thesiS, Gijjara~ A~i­culNra l Uni,ersity.

Upadhyay, K.G. and D"'e, I.M. (1977) MJiilll i)diry· man, 29(8),487.

Upadhyay, K.G .• Yyas, S.H ., Dave. 1.M. a~d, Thakar, P.N . (1 915) 1. Fd. Sci. Trch., 12(4).190.