Browsing by Author "Geevarghese, P I"

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Detergent potential of enzymes of dairy microflora and their effect on the shelf life of milk products
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 2010) Beena, A K; Geevarghese, P I
A study was conducted to assess the detergent potential of a spoilage protease enzyme obtained from the microflora of dairy plant environment. An attempt was also made to study the impact of selected enzyme producers on the shelf life of curd (dahi) and sterilised skim milk. A total of 71 bacterial isolates obtained from dairy environment were screened for their ability to produce spoilage enzymes like proteases lipases and lecithinases. Based on the spoilage potential, Pseudomonas aeruginosa (P12) isolated from pasteurised milk and Bacillus cereus (S4) isolated from sterilized skim milk were selected for further work. The influence of spoilage enzymes on selected physico-chemical characteristics of curd (dahi) and sterilized skim milk was evaluated by preparing the products from milk precultured with isolate P12 and S4. In general, proteolysis of milk was found to have an adverse effect on the quality of products. The stimulatory effect of proteolytic products of P12 and S4 on curd starters was evident from the higher values of acidity, firmness and syneresis in treated curd. The spoilage enzymes adversely affected the overall quality and shelf life of curd. In treated sterilised milk, tyrosine and NPN values were highly elevated. A linear correlation was found to exist between off-flavour and proteolysis. Curd and sterilised skim milk prepared from milk precultured with proteolytic organism were significantly different from that of control. The possibility of exploiting an alkaline protease from spoilage organism in dairy plant sanitation was also looked into. Environmental conditions for the production of alkaline protease by a psychrotrophic strain of Bacillus cereus (S4) was optimised in whey based medium. The protease used in this trial preferred an alkaline medium to remain stable. The enzyme was found to be stable over a wide temperature range of -10°C to 80°C and a pH range of 7.0 to 12.0. The metal ions Ca++, Mg++, Zn++ and Hg++ enhanced the enzyme activity. Lack of inhibition by Hg++ suggested lack of disulphide bonds in the active site of enzyme. Significant inhibition of activity by serine inhibitors indicated an essential serine residue in the active site of enzyme. The deleterious effect of EDTA on enzyme activity showed the supportive role of divalent cations. Marked residual activity on treatment with β-mercaptoethanol indicated the absence of cysteine residue for the enzyme. Enhancement of protease activity in the presence of surfactants and stability in the presence of H2O2 signified its potential to be used as detergent additive. Qualitative assessment of cleaning efficiency of inbuilt formulation substantiated the superiority of enzyme based formulations. Ammonium sulphate fractionation, dialysis and gel filtation using seralose 4B and Seralose 6B were effective in purifying the protease preparation by 141.31 fold. The purified protease was found to be a homogenous preparation of molecular weight of 50.5 kDa as determined by SDS PAGE.
Development and standardisation of low fat frozen dessert
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 2005) Rajesh, M B; Geevarghese, P I
An experiment was conducted to assess the feasibility of the incorporating mango pulp to replace milk fat in the preparation of low fat frozen dessert at 50 and 100 per cent levels (treatments) with the objective of developing a low calorie, low cost frozen dessert. The physico-chemical properties, organoleptic qualities, microbiological parameters and nutritional attributes of the low fat frozen dessert were studied and compared with normal ice cream (control). It was found that replacement of milk fat with mango pulp resulted in a mix with increased specific gravity, viscosity, titratable acidity and sucrose. However, a decreasing trend was observed in pH, fat and protein but normal value was observed in total solids since figuring of mix was done accordingly. It was observed that whipping ability and overrun of treatments decreased as the replacement level of mango pulp increased. But specific gravity, weight per litre and meltdown time increased with increase in replacement level. Replacement of milk fat with mango pulp does not produce any significant difference in microbiological qualities. Energy value was also lower in treatments as compared to control. Organoleptic quality of low fat frozen desserts were comparable to normal ice cream. Cost reduction of low fat frozen dessert mixes with 50 and 100 per cent replacement were 8.15 and 10. 86 per cent respectively as compared to control.
Evaluation of coffee husk for milk production in cows
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1979) Geevarghese, P I; Subramanyam, M
An investigation was carried out to find out the feeding value of coffee husk for milk production in cows using a total of nine Sindhi x Jersey cross bred cows, divided into three groups of three animals each. The experiment was for a period of 90 days. Coffee husk was included in the concentrate mixture at 0, 10 and 20 per cent levels. A switch – over design was used for the experiment. Coffee husk fed at 10 and 20 per cent levels in the concentrate ration did not significantly influence the body weight of animals. The total milk production of the animals getting coffee husk in the ration did not significantly differ from that of the animals on the control diet. The percentage of fat in milk, the total quantity of milk fat produced, the amount of four per cent fat – corrected milk, the percentage of total solids, the amount of total solids in milk, percentage of solids – not –fat, total quantity of solids – not – fat and the amount of solids – corrected milk remained the same for all the three groups of animals included for the study and no significant differences were noticed due to treatments. The physiological status of the cows in all the groups was normal and satisfactory. No significant difference due to treatments was noticed in some of the physical and chemical constants of butter fat. The dairy merit (percentage) based on efficiency of feed conversion was less of animals getting ten per cent coffee husk due to the reduced milk production and the greater feed consumption. The total cost of feed for producing one kg milk was Rs.1.42, 1.38 and 1.33 for animals getting 0, 10 and 20 per cent coffee husk in the concentrate mixture respectively. It was concluded that coffee husk upto 20 per cent level can profitably be incorporated in the concentrate mixture of dairy cows.
Technological evaluation of kera ice cream
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1996) Geevarghese, P I; Francis, U T
An experiment was conducted to assess the suitability of incorporating coconut fat in the form of coconut cream in preparing ice cream and ice cream mix powder replacing milk fat at 25, 50, 75 and 100 per cent levels (treatments) so as to reduce the cost of preparation of ice cream. The product developed was named as kera ice cream and the qualities were compared with normal ice cream (control). Kera ice cream was prepared with pineapple flavour and a combination of sodium alginate and glyceryl monosterate as stabilizer since it was found to be the most suitable. It was found that replacement of milk fat with coconut fat at any level does not influence the acidity, pH and specific gravity of kera ice cream mix. The relative viscosity of kera ice cream was increased as fat substitution level increased. Higher surface tension was observed for the control, and among treatments it showed a gradual increase as replacement level increased. It was observed that the overrun percentage increased as replacement with coconut fat increased. Contrary to this a decreasing trend in meltdown time was observed as percentage replacement with coconut fat increased. Whipping ability was lowest for the control during the first 5 min of freezing but it significantly increased during the second five min of freezing. Structural details of the ice cream revealed that as replacement level increased the air cell diameter and cell wall thickness increased. Organoleptic quality of kera ice cream were comparable to normal ice cream. The savings in cost of production for kera ice cream with 100 per cent replacement was calculated as 40.57 per cent compared to control. The properties of the reconstituted ice cream revealed more or less similar trend in characters like acidity, pH, specific gravity, overrun, meltdown time and organoleptic properties as that of the freshly prepared ice cream. The ultra structure of the kera ice cream mix powder particle were studied and it revealed that as replacement level increased the particle size also increased. Clumping of the particles and irregular surface were more evident at 75 and 100 per cent level whereas particles of the control and 25 per cent had smooth surface. Solubility index of the powder increased as percentage replacement increased. Significant difference could be noted with regard to bulk density and percent volume occupied by the powder particle. Storage studies were conducted with different packaging material and metallised polyester polyethylene was found to be the best. The moisture and titratable acidity of kera ice cream mix powder with and without antioxidant were significantly higher at any replacement level at 180 days of storage. The thiobarbituric acid value showed a significant difference for the powder without antioxidant at 120 days of storage and with antioxidant the difference could be noted at 180 days of storage. Peroxide value was recorded as zero at different periods of storage upto 180 days of storage. At 180 days of storage, powder without BHA at any replacement level showed significant difference whereas in antioxidant added powder difference could be noted at 75 and 100 per cent replacement levels. Nutritional qualities of kera ice cream was evaluated by rat feeding trials and was found that protein efficiency value and feed efficiency were comparable to ice cream diet. The cholesterol and triglyceride level in animals fed with kera ice cream and ice cream were also not different. Pathological examination of carcases and tissues of animals under treatment and control groups did not reveal significant changes indicating that incorporation of coconut fat cannot cause any untoward effect in organs and tissues of animals. It can be concluded that coconut fat can be incorporated in the prepartation of ice cream and mix powder with out any noticeable changes in the quality. Addition of antioxidant prolongs the keeping quality of the powder by two months. There is no health hazard in consuming the kera ice cream as revealed by the pathological examination of tissues from the experimental animals fed with kera ice cream.
Use of coconut cream in flavoured filled yoghurt
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1998) Pandiyan, C; Geevarghese, P I
trial was conducted to assess the suitability of incorporating coconut fat as coconut cream in flavoured yoghurt at various levels and the properties of the product were studied. A detailed review of literature on the various physico-chernical properties of yoghurt has been presented. The treatments were divided in to TC ( control without stabiliser) T2, T3, T4,T5 (25, 50, 75 and 100 per cent replacement level of milk fat respectively using coconut cream, without stabiliser), T6, T7, T8, T9 (25, 50, 75 and 100 per cent replacement level of milk fat respectively using coconut cream, with stabiliser 0.2 per cent) and the physico - chemical, micro-biological and organoleptic properties of the treatments were studied. Experimental yoghurt mixes prepared were analysed for titratable acidity, pH and total solids. Statistical analysis revealed no significant difference between control and treatments of the above characters. No significant difference was noticed in pH and fat between the control and treatment yoghurt samples whereas a significant difference (p< 0.01) in titratable acidity, protein, NPN, curd tension and viscosity was observed between control and treatments. Protein, NPN, curd tension and viscosity showed an increasing trend with increasing level of replacement. In treatments T6, T7, T8 and T9 sodium alginate produced slight improvement in curd tension and viscosity but it was not statistically significant. Tyrosine value increased at replacement level of 50 per cent onwards as compared to control. Coliform and yeast/ mould count showed no significant difference between control and treatments. Organoleptic quality of the products revealed no significant difference between control and treatments except for body and texture scores which showed a significant (p< 0.05) difference. Stabiliser sodium alginate produced little improvement in the body and texture score but was statistically not significant as compared to their corresponding pair. The results of the experiment revealed that coconut fat can be replaced upto 100 per cent level in the yoghurt preparation with an advantage of cost saving, increased protein, NPN, curd tension and tyrosine value. Even upto 100 per cent replacement level overall total organoleptic scores were comparable with control.
Use of condensed coconut water in yoghurt
(Department of Dairy Science, College of Veterinary and Animal Sciences, Mannuthy, 1996) Malarkannan, S P; Geevarghese, P I
An attempt was made to incorporate condensed coconut water in partial replacement of MSNF at 25 and 50 per cent level in yoghurt and to study the properties of the product which were compared with normal yoghurt. An exhaustive review of literature on the various physico – chemical properties of yoghurt and other fermented milk products has been presented. The procedure for the analysis of coconut water and condensed coconut water for its chemical composition, mineral profile and method of condensation has been described. The quantity of ingredients for yoghurt preparation was derived by linear programming model. The treatments were divided into TC (control), T2 (25 per cent replacement of MSNF using condensed coconut water without gelatin), T3 (T2 + gelatin at 0.5 per cent level), T4 (50 per cent replacement of MSNF using condensed coconut water without gelatin) and T5 (T4 + 0.5 per cent gelatin). A pre – trial was conducted to find out the ideal combination of starter culture and gelatin to be added to give good quality yoghurt. A combination of four per cent starter culture with 0.5 per cent gelatin produced good quality yohurt and this combination was used in the subsequent trials. A pilot heat stability test was conducted in treatment mixes to find out the amount of trisodium citrate required to provide sufficient heat stability. Yoghurt mixes prepared were analysed for titratable acidity, pH and total solids. Statistical analysis revealed no significant difference between control and treatments for the above. No significant difference was observed in pH and fat between the control and treatments. A significant difference (P < 0.01) in titratable acidity, protein and NPN percentage was observed between control and treatments. The curd tension and viscosity showed a decreasing trend with increasing level of replacement but this properties improved to certain extent by addition of gelatin. The setting time and NPN content showed an increasing trend as replacement level increased and this may be due to high mineral and NPN content in coconut water. There was no significant difference in tyrosine value between the control and treatments T2 and T3. No significant difference was observed in L. bulgaricus count and coliform count between control and treatments, whereas but S. thermophiles and yeast and mould count showed significant difference between control and treatments which may be due to a stimulatory factor in coconut water for yeast and mould and inhibitory factor for S. thermophiles resulting in slow growth. Organoleptic quality revealed that 25 per cent replacement of MSNF with or without addition of gelatin produced comparable scores as that of control yoghurt. A savings of 13.95 per cent and 8.14 per cent in cost can be achieved by 25 per cent replacement of MSNF with or without addition of gelatin respectively. The results of the experiment revealed that 25 per cent replacement of MSNF with condensed coconut water can be successfully tried in preparing yoghurt without affecting the physic – chemical and organoleptic properties together with considerable reduction in cost.