EFFECT OF NISIN ON SHELF LIFE OF LASSI

Transcription

1 J Dair:r,;ing, Foods & H.S.. 29 (2) : 79, 21 AGRCULTURAL RESEARCH COMMUNCATON CENTRE EFFECT OF NSN ON SHELF LFE OF LASS B.K. Pawar, R.M. Chaure, D.M. Choudhari and D.K. Kamble Department of Animal Science and Dairy Science Post GraduaTe nstitute. Mahatma Phuie Krishi Vidyapeeth. Rahuri ndia \ ABSTRACT Lassiwas prepared by using five levels of nisin i.e. To (Control), Tl (1 U/m), T2 (2 V ml), T3 (3 V/ml) and T4 (4 V/m). % cane sugar,.1 % salt and 1 % water level was used in all treatments. The Lassiprepared by addition of 4 U/ml (T ) nisin was organoleptically 4 superior over the other treatments for the parameters colour and appearance (.1). body and texture (.2), flavour (.1), acidity (.22) and overall acceptability (.1), respectively. Treatments To' T, 1 T2 and T3 were acceptable up to th, 9 th, 11th and 12th days, respectively. While treatment T4 was acceptable up to 1 th days. While studying microbial quality of preserved Lassiunder refrigeration temperature ( o q. The treatment To (Control) showed the higher SPC, YMC and E.coli count during study ranged from x 1 7, X 1 7 and. 2.x 1 7, respectively. Whereas the treatment T4 showed lowest microbial count over the other treatments i.e. ranged from SPC ( x17), YMC (..3x1 7 ) and E.coli (4. 1.x 1 7 ), respectively. Key words: Lassi Nisin, Organoleptic. Microbial quality. NTRODUCTON Lassiis a popular indigenous fermented milk beverage. which is usually prepared by mixing dahi and water in required proportions. The fermented milk products are prepared by the action of microorganisms by adding starter culture, which modifies the substrates biochemically, and organoleptically into edible products and are thus generally palatable, safe and nutritious (Campbell Platt, 1994). Nisin is an antibiotic product by the lactococcus lactis var lactis is effective against spore farmers and gram-positive bacteria. Hence, widely used for the preservation of wide range of dairy products. t is non-toxic and obtained 'GRAS' status. Many chemical preservatives are harmful to health hence people prefer the natural food preservative and nisinisoneofthem.n 199, joint food additive organization WHO expert committee on "Food Additive" gave international acceptance for nisin. The average dally intake being -33-unitsl kg body weight and the maximum level of addition is 1 mg of nisin per kg of food product. Nisin is used for enhancing sheif life used in dairy products like khao. iassj. shrikhand. cheese. pasteurized milk. paneer. and yoghurt. The iassj has a very limited shelf life at room temperature and even at refrigerated temperature. The demand for lass! is increasing day by day. The consumer use to enjoy lassj at restaurant, bus stand, railway station and during journey they want to carry lassjbut due to limited shelf life there are many problems in marketing of lassi. Therefore the present study was planned to enhance the shelf life of lassj by incorporating the various nisin levels vjz., 1 lu ml, 2 lu ml. 3 lu ml and 4 lu ml in lassi. MATERAL AND METHODS Fresh cow milk was used for product preparation during investigation. Freeze-dried LF-4 (Lactic fermenfh) culture obtained from Division of Dairy Microbiology, NDR, Kamal was used for study. The culture is activated as per the directives given by NDR, KamaL n order to keep the culture active, it was propagated once in a week. t was stored at

2 J. DARYNG. FOODS & H.S. SOC in a refrigerator and utmost, care was taken to avoid contamination to culture. Nisin obtained from Duke Thomson's nternational, ndore (MP) and cane sugar, salt etc. purchased from local market were used for preparation of Lassi. Packaging material Low density polyethylene bags of 2 ml capacity having film thickness of 2 guage were used for keeping product samples under storage study. Experimental trials: n this experimental trials, /assi was prepared by using five levels nisin (, 1,2, 3. 4 U/Ml). sugar level per cent. water level 1 per cent and salt level.1 per cent i.e. common for all treatments added in /assj as finalized by organoleptic evaluation of lassi in preliminary trials. Culture used for /assj preparation was LF-4. Aim of experimental trial is to find out most acceptable treatment in /assi. Details of treatment combination Treatment Nisin level U/ml To (Control) T 1 1 T2 2 T 3 4 Preparation of lassi Lass! was prepared by using the procedure described by Gupta and Kulkarni (193) with slight modification. F1w diagram for preparation of lassi Milk Standardization to 4 per cent fat Pasteurization of milk ± 1 GCi 1 min Cooling 3 t! Addition of starter culture 2 DC 2 per cent ncubation at 3 DC (12 hrs) i! Dahi, Breaking of coagulum, Add sugar ( \ water ( 1 % salt (D.1% t Nisin Uiml (, 1. 2, 3, 4) Blending (mixing)! Packaging in LDPE pouches t Storage DC) The lot of standardized milk (4 fat) was heated to temperature ± 1 DC for 1 min and then cooled 3 ± 2. t was inoculated with starter culture (LFAO) at rate of 2 per cent incubated at 3 C for 12 hrs. The curd with well developed body and texture obtained was divided into five portions and lassi was prepared by adding sugar, water. salt and nisin as per treatment. The mixture is blended and filled in LDPE pouches. Samples were taken for organoleptic evaluation. chemical and microbial analysis. Separate samples were drawn for respective analysis. Organoleptic quality of lassi The fresh and refrigerated stored /assj ( DC) samples were subjected to organoleptic evaluation. The panel of semi-trained judges was provided the prepared samples of /assj for sensory evaluation. Each treatment was given code number, which was changed during each replication so as to avoid its identity. The scoring was recorded by using '9' point Hedonic scale. Microbial analysis of lassi 1. Standard plate count As per standard plate count method describe in S Yeast and mould - Determined as per manual of Dairy Bacteriology CAR, (Anonymous, 192)

3 Statistical analysis The data were tabuiated and analyzed according to Snedecor and Cochran (1994) method Completely Randomized Block Design (CRD). RESULTS AND DSCUSSON Organoleptic quality of lassi during storage at refrigeration temperature DC: The panel of semi trained judges consisting of five members was given samples of fresh and refrigerated stored (for 1 days) from the five treatments for evaluation of their organoleptic qualities by using 9 point Hedonic scale. Each treatment was given code number, which was changed during each replication so as to avoid its identity. The scores given by the judges for individual quality attributes were computed to get means and these means were subjected to statistical analysis. Colour and appearance The score for colour and appearance of lassi are depicted in Fig.1 statistically significant. The colour and appearance score varied from 7.72 to. on fresh lassisample. A gradual increase in the colour and appearance score was noticed during to 3 rd day of storage, but decreased in the colour and Vol 29. No appearance score after 3 rd day and sample To' T:, T 2, T3 and T4 was acceptable up to th 9 th, 11 rh, 12 th and 1 th day respectively. T4 had highest colour and appearance score as.1. Body and texture The score on organoleptic evaluation of iassifor body and texture attribute represented m Fig. 2 are statistically significant. The body and texture score of fresh samples ranged from 7.73 to 7.97 and on th day of storage ranged from. to.1 while sample T, 1 T 2, T3 and T4 recorded score from.4 to.12,.4 to.1,.4 to.17 and.3 to.2, respectively during storage period. Control To, T), T2 and T3 were acceptable up to rh, 9 th, 11 th and 12 th days. respectively. While T4 was acceptable upto 1 th day ranged from "like slightly". Treatment T4 had highest body and texture score as.2 over other treatment. Flavour The score on organoleptic evaluation of lassi for flavour attribute represented in Fig. 3 are statistically significant. t is apparent from the data presented in Fig. 3 that flavour values increased up to 3 rd day and slowly decreased continuously as storage period increased. The flavour is the most important component of \. --TO ---Tl --T2 ---T3 --T41 ' h o U rj) t1j h m (). " h ;:l o " u. o Storage period (davs) Fig. 1 : Effect of nisin on colour and appearance (score) of lassi during storage at Soc.

4 2 J. DARYNG. FOODS & H.S. sensory quality, A gradual deterioration was slightly". Treatment T, had highest flavour observed in the flavour score during storage and score as.1 over other treatment. To'. Te and were acceptabie up to Acidity t. 9: h, The score allotted for acidity as a 11 th and 1 day respeoctively. While T4 was sensory attribute of lassi are depicted in Fig. 4 acceptable up to 1 day ranged from "like showed statistically significant. The acidity,. --TO ---Tl --T2 --T3 T4 'Z' ' 7. v v!-. 7 ::l ;<: C,) ". >. " cc Fig. 2 : Effect of nisin on body and texture (score) of lassi during storage at Soc.. --TO ---Tl --'1'2 --1'3 --T v.!-. ::l G: Fig. 3 : Effect of nisin on body on flavour (score) of lassi during storage at Soc.

5 Vol. 29. :-Jo score varied from 7.4 to. on the day acidity.22. Trearment T4 was superior over all of production, Acidity score increased up treatment in regard to the acidity. to 3 rd day and after 3 rd day decreased the acidity score. Treatm ents To' T Overall acceptability l' T2' and TL were acceptable up to th, 9 tr,. 11 The score for overall acceptability of Jassi 12 th and 1 th day respectively. During are depicted in Fig are statistically significant. The storage treatment To had highest score of overall acceptability score varied from 7.77 to.1 \ 9 --TO --Tl --'1'2 ---T3 ->li-t o o Fig. 4 : Effect of nisin on acidity (score) of lassi during storage at SoC.. Q)!-. 7. () 2 & 7 :E crj +-'. Q.) () (). crj - ca... v ;: Fig. : Effect of nisin on overall acceptability (score) of la.ssi during storage at Soc.

6 4 J. DARYNG. FOODS & H's. on fresh sample of lassi. A gradual increase in Yeast and mould the overall acceptability score was noticed Yeast and mould perhaps are important during to 3" day of storage but decreased in group of microorganisms responsible for the overall acceptability score after 3 m day and spoilage of dairy products. The result of yeast sample To,,To and T, was acceptable up to and mould count represented!n Fig 7.Yeast th, 9 th 11 i; and-1 dy respectively. While and mould count was not observed on zero and, T4 was acceptable up to 1 day ranged from first day, YMV observed on second day, To "like slightly". Treatment T4 had highest overall treatment had highest microbial load 9 x 1 7 acceptability score as.1 over other cfu/m! than rest of the treatment it was followed treatment. T4 treatment was superior for overall by treated samples T1 ( x 1 7 cfu/ml), T2 (7 x acceptability of lassi. 1 7 cfu/mll, T3 ( x 1 7 cfu/ml) TreatmentT 4 ( Microbial quality of Jassi during storage x 1 7 cfu/ml) showed least microbial load than Tn' T" T2 and T at refrigeration temperature C Yeast and mould count was observed 3 Standard plate count (SPC) highest in Tn treatment due to which the sample The lassi samples under different deteriorated md was not acceptabie, These counts treatment preserved at C temperature showed were more or less similar to the results observed by variation in microbiological quality during the Naresh Kumar and Prasad (199) and Dave et al. storage period (Fig. ). On zero day control (1991) in lass! samples (To) had highest microbial load 1.32 E. Coliform x 1 7 cfu/ml than rest of the treatment it was The presence of coliform in dairy followed by treated sample T (1. x 1 7 cfu/ products is suggestive of unsanitary conditions ml), T2 (1.4 x 1 7 cfu/ml), T3 (1.4 x 1 7 or practices followed during production process cfu/ml) and T4 (14.97 x 1 7 cfu/ml) treatment and taking inadequate care during post showed lowest microbial load than To. T1' T2 processing. From the data given in Fig. it is and T3 due to level of nisin increase microbial revealed that the coliform count was absent on load decrease showed in Fig. zero, first and second day on third day coliform TO --T1 T2 ---T3... T4 14 Z 12 C) P... [jj 1 c iii Fig. : Effect of nisin on SPC of lassi during storage at o C.(cfu x l7/ml)

7 VOL 29, No ':J 2: 2(; > <;j i:: 'if) 1 Z '/ i4 ] Fig. 7 : Effect of nisin on YMC of lassi during storage at "C.(cfu x 1 7 /mo count was observed highest in To (. x 1 7 results observed by Mohanan et a, (194) and cful mil and lowest in T4 (4 x 1 7 cfu/ml). Dave et aj. (1991). Coliform count in lassi was in range of ( to CONCLUSON X 1 7 cfu/ml), it is below the standard t may be concluded that addition of 4 prescribed by SS (Le. up to 1 X 1Q7cfu/ml). U/ml nisin with percent sugar, 1 percent A graduate decline in count of coliform during water and.1 percent salt combination for storage and their absence of 7th day indicated preparation of lassi increased the shelf life of their inhibition by lactic acid and lassi and produced best quality of lassi as antimicrobial. These counts were similar to the compare to other treatments. REFERENCES Anonymous. (19) Handbook of Food Analysis. Part-X Dairy Products. Bureau of ndian Standards. New Delhi. Anonymous. (192) Manual of Dairy Bacteriology CAR. New Delhi Compbell Platt. G (1994) Food Res. nter., 27: Dave, R. 1(1991) AsianJ DailY Res., 1; Gupta, S. K and Kulkarni. S. (193) ndian Daiyman. 3 (1): 93. Mohanan. K Ret a/(194) ndian J DaiJy Sci.. 37 (2): 177. Nareshkumar and Prasad. D. N. (199) ndian J Anim. Sci. (): 2 2. S: 42. (199) Estimation of total bacterial content using standard plate count method. ndian Standard nstitution. Manak Shavano New Delhi. S: 273 (Part ). (1971) Guide for Sensory Evaluation of Food. S!, New Delhi. Snedecor, GW. and Cochran, w.g. (1994). Statistical Method. th Edn. Oxford and.d.b. Pub. Co., Calcutta,lndia.