Browsing by Author "Prasad, V"

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Effect of incorporation of condensed cheese whey and bifidobacterium bifidum in Yogurt
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1994) Mirza Ismail, Baig; Prasad, V
An experiment was conducted to assess the possibility of utilization of whey solids in different forrrs in yogurt as a substitute for NDM and also E bifidum as an adjunct with the view to improve the therapeutic value of yogurt A detailed review of literature was presented on the morphological and physiological characteristics of starter cultures importance and utilization of whey solids effect of long term storage on starter bacteria and other related aspects Methodology of condensation of cottage cheese whey preparation of whey protein dispersion and manufacture of set and frozen yogurt has been described Important analytical procedures were presented The experiment comprised of part A and part B based on the starter culture The mix under the part A were fermented with conventional yogurt starter culture viz S5 salivanus subsp thermophilus and L delbrueckn subsp bulgaricus as against this the mix under part B were fermented with conbination of conventional yogurt starter and B bifidum Fa h part comprised of four treatments based on types of mill solids used to raise the content of SNF to 13 per For A-II and B II condensed whey was used to replace 50 percent NDM Mixes under A III and B III were fortified with condensed whey to replace 100 per cent NDM and whey protein dispersion was used to replace complete NDM under A-IV and B-IV The results obtained had been compared with similar reported studies and conclusions were drawn The data regarding the starter bacterial count indicated the optimum growth of thermophilus bulgaricus and bifidobacteria in yogurt fortified with different forms of vihey solids The count of thermophilus and bifidobacteria were higher with the fortification of whey solids m yogurt mix and the growth of bulgancus was not adversely affected in the presence of the whey solids Incorporation of B bifidum stimulated the growth of thermophilus however it was found to have some inhibitory effect on bulgaricus count The inhibitory effect of B bifidum on bulgaricus was lesser in presence of whey solids than in yogurt fortified with NDM Optimum growth of B bifidum was obtained when grown in association with conventional yogurt culture cent For mixes under A-I and B-I fortification was with
Effect of lactose hydrolysed condensed whey and bifidobacterium bifidum in yogurt
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1995) Beena, A K; Prasad, V
An experiment was conducted to assess the possibilities of utilizing whey solids in the form of condensed whey or lactose hydrolysed condensed whey as a substitute for NDM. Their effect was also studied in conjunction with B. bifidum as a dietary adjunct. A detailed review of literature has been presented on the issues of lactose intolerance, hypercholesteraemia, beneficial effects of lactic acid bacteria in alleviating these conditions and also on acid tolerance and bile tolerance of cultures used in the present study. Methodology for the condensation of cheese whey, estimation of lactose in whey, B-galactosidase specific activity in the products, total cholesterol, HDL-cholesetrol and triglycerides in serum, assessment of acid tolerance and bile tolerance of lactic cultures used here have been detailed. The experiment comprised of preparation of yogurt and bifidus yogurt using three methods of fortification viz. skim milk powder, condensed whey and lactose hydrolysed condensed whey. The products prepared were then analysed for B-galacosidase specific activity. Hypocholesteraemic and growth promoting effects of these products were assessed in a biological study using rats. Hypocholesteraemic and growth promoting effects of whole milk was also assessed in the biological study. Acid tolerance and bile tolerance of lactic cultures used in this study were also determined, in vitro. From the above study, following conclusions were made. 1. B-galactosidase specific activity was noticed in substantial amount, in yogurt under different treatments. Bifidus yogurt showed a reduction in B-galactosidase specific activity, however, the activity was found to be enhanced when fortification was done with lactose hydrolysed condensed whey indicating that bifidus yogurt fortified with lactose hydrolysed condensed whey is superior. 2. No significant hypocholesteraemic effect was noticed in rats due to consumption of milk. All the rats fed with yogurt and bifidus yogurt except that given yogurt A1 showed a substantial reduction in serum LDL-cholesterol level and cardiac risk factor. However, bifidus yogurt supplemented with whey proteins showed maximum hypocholesteraemic effect and lowest cardiac risk factor showing the superiority of bifidus yogurt with whey proteins. 3. All rats given yogurt and bifidus yogurt showed a better daily weight gain when compared to the group fed whole milk along with feed and cholesterol. 4. Evaluation of acid tolerance of lactic cultures showed that, among the three cultures tested, B. bifidum exhibited maximum acid tolerance followed by S. salivarius ssp. Thermophilius. L. delbrueckii spp. Bulgaricus was found to be acid sensitive. 5. Bile tolerance study of pure and active cultures revealed that none of the tested cultures were completely inhibited by bile indicating theses cultures were bile tolerant to some extent.
Effect of nisin on the keeping quality of Dahi
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1992) Sreeja Ramachandran; Prasad, V
Evaluation of the feeding value of tea waste for milk production in cows
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1978) Prasad, V; Subramanyam, M
An investigation was carried out to find out the feeding value of tea waste for milk production in cows. A total of nine Jersey x Sindhi crossbred cows were divided into three groups of three animals each and fed tea waste in their concentrate ration at 0, 15 and 25 per cent levels. A switch – over design was used for the experiment.
Immobilization of beta galactosidase for production of fermented milk products with low lactose
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1996) Geetha, R; Prasad, V
An immobilized β – galactosidase enzyme system was developed using permeabilized cells of K. fragilis as an enzyme source and food grade agar as the immobilizing agent. This was utilised for hydrolysing lactose content present in milk, which in turn was used for preparing selected fermented products with low lactose content. An attempt was also made to assess the possibility of utilisation of whey as a medium for culture maintenance with a view to utilise the by – product. A detailed review of literature has been presented about β – galactosidase specific activity of different organisms, various immobilization techniques,influence of lactose hydrolysis on physico chemical properties of the product and also about the utilisation of whey as a media for culture maintenance. The experiment comprised of determination of β – galactosidase specific activity of permeabilized cells of three selected organisms and assessing the suitability of agar and sodium alginate as immobilizing agents. Since β – galactosidase specific activity was found to be the highest for K. fragilis, it was selected as the best enzyme source. Agar was selected as the suitable immobilizing agent because it was found to be safe, economical and comparatively more efficient. Using these two raw materials an efficient immobilized enzyme system was developed and its efficiency was assessed by estimating the rate of lactose hydrolysis at fixed time intervals. Selected strains of starter bacteria were screened for their performance in four different media viz. Skim milk, 50 per cent lactose hydrolysed skim milk, condensed whey, and 50 per cent lactose hydrolysed condensed whey. Two media were selected from among the four, which stimulated the starter activity and used for further studies. Three different products viz., yogurt, bifidus yogurt and acidophilus milk were prepared using 50 per cent lactose hydrolysed milk obtained by passing through the immobilized enzyme system and cultures maintained separately in lactose hydrolysed milk and lactose hydrolysed whey. Two control products were prepared with ordinary milk and above described cultures. All the three products under different treatments were analysed for acidity, pH, tyrosine value, total lactic count and sensory evaluation. The results obtained in the study were compared with similar reported findings and the following conclusions were made. 1. Permeabilized cells of K. fraglis possessed better B – galactosidase specific activity than the cells of S. thermophiles and L. delbrueckii sub sp. bulgaricus. 2. Food grade agar was found to be an efficient immobilizing agent than sodium alginate. 3. The immobilized enzyme prepared with 10 g of K. fragilis could hydrolyse 50 per cent of lactose content present in 250 ml of milk, after holding in the column for four hours at room temperature (300 C). 4. The rate of lactose hydrolysis was found to be the maximum within first half an hour, thereafter a decline in the rate of hydrolysis was observed. 5. This system was repeatedly used in five batches without any change in its efficiency or mechanical stability of the beads but after which a reduction in activity was noticed. 6. A slight brownish discolouration was observed on the beads when the column was stored for a long period. 7. Repalcement of skim milk with whey was a starter media slightly enhanced the activity of cultures, especially, S. thermophilus, L. lactis and B. bifidum whereas L. acidophilus and L. delbrueckii sub sp. bulgaricus performed better in skim milk, especially when the media was subjected to lactose hydrolysis. 8. The utilisation of lactose hydrolysed milk for preparation of products slightly enhanced the acidity, proteolytic activity and viable cell count of yogurt, bifidus yogurt and acidophilus milk. 9. In the case of treatment yogurts (Y1 and Y2) prepared with lactose hydrolysed milk, a significantly higher protolytic activity was observed. 10. Organoleptic evaluation indicated that the utilisation of lactose hydrolysed milk and cultures maintained in lactose hydrolysed skim milk and whey did not affect the flavour and textural characteristics of yogurt. On the contrary the flavour as well as body and texture scores of bifidus yogurt and acidophilus milk were slightly improved by this technique.
Lactobacillus acidophilus as a dietary adjunct in dahi and yogurt
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1995) Appalo Eleven, S; Prasad, V
An experiment was conducted to study the beneficial effect of incorporating L. acidophilus in dahi and yogurt as a dietary adjunct. An attempt was also made to find out the bile tolerance of L. acidophilus and other lactic acid bacteria. An exhaustive review of literature has been presented on the issues of lactose intolerance and hypercholesteremia and the beneficial effects of lactic acid bacteria in alleviating these drawbacks, with a special emphasis on bile tolerance and intestinal colonisation. The methods of analysis of some important components of dahi and yogurt have been detailed. Treatment dahi was prepared by inoculation with L. acidophilus in addition to normal dahi cultures. This was compared with control dahi prepared with normal cultures alone. Treatment yogurt was prepared with inoculating L. acidophilus alongw ith normal yogurt cultures. This wascompared with control yogurt prepared using normal yogurt cultures. The samples were then analysed for various parameters. There was an increase in the p-galactosidase specific activity of treatment dahi when compared to the control dahi. But m the case of yogurt, the treatment yogurt was having a low 3-galactosidase specific activity when compared to the control yogurt. Control dahi showed inhibition against E. aerogenous, M. falvous, E. coli and S. aureus. It did not showed any inhibition against B. cereus. Treatment dahi exerted a significantly high inhibition zone against all the test organisms m comparison to control dahi. Control yogurt inhibited only E. aeroqenous and E. coli. Treatment yogurt exerted a significantly high antibacterial activity against all the organisms tested. Of, all the lactic acid bacteria tested for their ability to grow in the presence of 0.3 per cent of Oxgall, only L. acidophilus grew satisfactorily. L. delbruecii ssp bulgancus showed a poor growth, whereas S. salivanus ssp thermophilus Lac. lactis and Lac, lactis ssp diacetylactis failed to grow in the presence of Oxgall. Both the dahi and yogurt treatments showed higher hypocholesteremia when compared to their respective controls. The total serum cholesterol level, serum triglyceride, LDL- Cholesterol and cardiac risk factor of the treatment groups were significantly lower than the respective controls. The HDL-Cholesterol was high m both the treatments when compared to the respective controls. The growth rate of treatment dahi group was low when compared to the control dahi group. But the treatment yogurt group showed a higher growth rate as compared to the rats fed on control yogurt.
Qualitative changes of yoghurt prepared from milk preserved by different methods
(Department of Dairy Science, College of Veterinary and Animal Sciences,Mannuthy, 1990) Prasad, V; Sukumaran, M V
An experiment was conducted to study the qualitative changes of yoghurt prepared from milk preserved by different methods. An attempt was also made to study the efficiency of LP system in controlling psychrotrops in refrigerated milk thereby extending the keeping quality of such stored milk. The efficacy of the system was compared with pasteurized milk and raw milk stored under similar conditions. An exhaustive review of literature has been presented on the use of various preservation methods employed in milk, quality of yoghurt and other related aspects. The methods of analyses of some important components of milk and yoghurt has been detailed. The milk after collection were divided into three portions and used for various treatments A (raw milk as such), B (laboratory pasteurized) and C )LP activated). Samples in each treatment were again divided into four parts and stored under refrigeration for 0, 24, 48 and 72 hours for further analysis and yoghurt preparation. When raw milk was stored under refrigeration, acidity developed to a significantly high level (P < 0.05) at the end of 72 hours of storage whereas no significant increase in activity was noticed in treatments B and C. This result was corroborated by a decrease in both psychrotrophic and total bacterial counts in milk under treatments B and C. So it was concluded that the development of acidity in treatment A could be due to bultiplication of microbes particularly psychrotrophs. In B and C its growth was arrested by the treatments. Hydrogen peroxide and thiocyanate were detected in all raw milk samples at a level of 3.78 and 7.33 ppm respectively. The level of H2 O2 and SCN – used for the activation of LP system for the study were found to be adequate, since the psychrotrophic count in milk at the end of 72 hours in treatment C was less than that found in treatment B. The residual H2 O2 and SCN – contents at the end of 72 hours were found to be within the normal level found in milk thus having no health hazards, by this method of preservation. When yoghurt samples were prepared from stored milk no significant differences between treatments were noticed in the values of fermentation period, acidity, pH, total proteins and total solids. A significant increase in NPN and tyrosine values were noticed in yoghurt prepared from milk under treatment A indicating extensive proteolysis in milk during storage under this treatment. However, no difference was noticed between treatments B and C. Diacetyl and acetaldehyde were produced at a desirable level in yoghurt samples under all the three treatments. A proper ratio of Str. Thermophiles – 6 and L. bulgaricus – 4 was found to be maintained in all yoghurt samples. On organoleptic evaluation the yoghurt prepared from milk under treatment C could not be distinguished from other two treatments. In fact, yoghurt under C got a higher total score on organoleptic evaluation than A and B. Low score for body and texture, and falvour was observed under treatment A. This may be attributed to the effect of growth of psychrotrophs in raw milk during refrigeration. From the results, it was concluded that good quality yoghurt can be prepared from milk stored under refrigeration following pasteurization or LP activation. Yoghurt samples prepared from milk stored under treatment A was found to be of inferior quality when compared to B and C. The result also confirmed that LP system can be recommended as a safe preservative for extending storage life of refrigerated milk. When such stored milk was used for yoghurt production, no significant difference in the quality was noticed when compared to yoghurt under treatment B. Suggesting that LP activated milk can be conveniently and economically used for the production of fermented milk products like yoghurt without any apparent harmful effect.
Survivability of microencapsulated lactobacillus acidophilus L A-5 synbiotic icecream
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 2009) Albert Arockiaraj, P; Prasad, V
An experiment was conducted to study the efficiency of microencapsulation to improve the survivability of L. acidophilus LA-5 along with the addition of oligofructose in the formulated synbiotic ice cream. The treatment mixes and ice creams were analyzed for various properties by using standard procedures and compared with the control. It was found that addition of L. acidophilus LA-5 either in free or microencapsulated state has not affected the acidity and pH of the ice cream mix. Microencapsulation of L. acidophilus LA-5 increased the specific gravity of the ice cream mix along with addition of oligofructose. Fat, probiotic and coliform counts of the all the treatment ice cream mix were similar to that of the control. The fat content of all treatment ice creams were similar to that of their ice cream mix. Addition of free or encapsulated L. acidophilus LA-5 has not affected the overrun or whipping ability of ice cream. The pH of ice cream was significantly reduced by L. acidophilus LA-5 in free state rather than in microencapsulated state. Addition of oligofructose and low pH increased the meltdown time of ice cream. The weight per litre of ice cream increased significantly with addition of oligofructose than by addition of L. acidophilus LA-5 in both state. Fat and sugar replacers increased the specific gravity of ice cream mix, weight per litre of ice cream and reduced the whipping ability, overrun and meltdown time. Reduction in probiotic count of ice cream was more pronounced during freezing than hardening and storage. The overall probiotic count in ice cream with microencapsulated form of L. acidophilus LA-5 was significantly higher than the ice cream with free form of L. acidophilus LA-5. Low level of fat content has not affected the survivability of L. acidophilus LA-5 in low fat synbiotic ice cream. Overall sensory acceptance of ice cream with microencapsulated L. acidophilus LA-5 was similar to that of the control. Free form of L. acidophilus LA-5 caused slight acidic or sour flavour in the ice cream. Low fat synbiotic ice cream had lowest sensory acceptability. Cost of production of production of synbiotic ice cream with microencapsulated L. acidophilus LA-5 was more than the control. Addition of microencapsulated L. acidophilus LA-5 did not affect any of the technological parameters of the formulated synbiotic ice cream. Microencapsulation efficiently improved the survivability of L. acidophilus LA-5 in the ice cream and ascribed to it the status of a suitable functional food to deliver the recommended level of probiotics with very good sensory attributes to the consumer.