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ThesisItem Open Access Development of enzyme based chromogenic strips for detection of selected adulterants in milk(College of Veterinary Science, Assam Agricultural University, Khanapara Campus, 2022-09) Muktan, Priya; Raquib, MasukThe present investigation was carried out to develop an enzyme based chromogenic strip for detection of selected adulterant in milk. The experiment was carried out in the Department of Livestock Products Technology, All India Coordinated Research Project on Post Harvest Engineering and Technology and Department of Veterinary Biochemistry, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati- 781022. An enzyme based chromogenic test strip using Whatman filter paper grade 602 and Whatman filter paper No. 1 was developed for the detection of glucose, starch and urea in milk using glucose oxidase, amyloglucosidase and urease enzyme in the presence of potassium iodide for starch and glucose and phenol red for urea as an indicator. The activity of the test strip was validated in both raw and processed milk spiked with the respective adulterants. All the enzyme based test strips were able to detect 2mg/ml of glucose, starch and urea with definite ring formation within a specified time period. The response time for the detection of glucose, starch and urea in milk was noted at 31.22±0.014 and 30.00±0.05, 128.3±0.88 and 129±0.57 & 99 ±0.57 and 109.67 ±0.88 sec, respectively in Whatman filter paper grade 602 and Whatman filter paper No. 1 at a pH of 4.5, 4.5 and 8.0 and a chromogenic substrate concentration of 40, 50 and 1 mg/ml. The optical density of glucose, starch and urea was found to be almost linear. As the concentration of the substrate increase the optical density value tends to increase proportionately. The test strip was tested for true positive and true negative results. The limit of detection for glucose, starch and urea were found to be 1.0, 2.0 and 0.8 mg/ml, with response time of 1, 4 and 3 min, respectively. To see the effect of different processing condition on the ability to degrade glucose, starch and urea in milk, all the test strips showed positive response except in household boiling condition wherein the response was delayed by a few min. The enzyme based test strip were 100 percent specific for detection of glucose, starch and urea as presence of similar types of compounds did not interfere with the positivity rate of the strips which was verified with help of confusion matrix. The shelf life of enzyme based chromogenic glucose, starch and urea test strips were found to be 40 and 30, 34 and 30 & 42 and 34 d, respectively for Whatman filter paper grade 602 and Whatman filter paper No. 1, respectively when stored under refrigerated storage (7±1oC) and ambient storage (29-32oC) condition in airtight glass containers.ThesisItem Open Access Quality characteristics of soy milk blended yoghurt(College of Veterinary Science, Assam Agricultural University, Khanapara Campus, 2022) Khatun, Arifa; Borpuzari, TA study was carried out to evaluate the quality characteristics of soy milk blended cow’s milk yoghurt. The study was carried out in the laboratories of the Department of Livestock Products Technology, the All India Coordinated Research Project on Post-Harvest Engineering and Technology, the Department of Veterinary Biochemistry, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati- 781022 and in the Central Analytical Instrumentation Facility, Guwahati Biotech Park Incubation Centre, Amingaon, Kamrup, Guwahati-781031 during the period from December, 2021 to September, 2022. Organic whole soybeans procured from the local super markets were used for preparing sprouted and unsprouted soy milk. The NCDC 144 obtained from the National Dairy Research Institute, Karnal was used @ 3% (v/v) as yoghurt starter culture in the study. The effects of addition of soy milk on the pH, per cent lactic acid content, free fatty acids, flavour and colour profile, proximate composition, microbiological quality, sensory scores and the best before end of the cow’s milk yoghurt were studied. A gradual decrease in the pH values of the Control samples as well as in all the samples of the Treatment groups was noted. Fatty acids and flavour compounds were identified with the help GC-MS. The colour profiling revealed that L, a and b values were the highest in control samples followed by T2 group while the samples of T1 group showed the least values for these colour components. The samples of T2 group contained the maximum mean values of 4.23±0.02, 19.65±0.10 and 1.26±0.00% for protein, total solids and ash, respectively, while the Control samples showed the maximum mean value of 4.37±0.03 and 82.96±0.12% for fat and moisture, respectively. The protein content of the cow’s milk yoghurt incorporated with 25% of soy milk had higher protein content than the cow’s milk yoghurt. Addition of sprouted soymilk increased the per cent protein content of the cow’s milk yoghurt than those incorporated with unsprouted soymilk. The highest mean TVC of 9.13±0.01 log10cfu/ml was recorded in the samples of the T2 group which might be due to rapid growth of the added starter organisms accelerated by the synergistic effect of the germination metabolites of soybeans. Coliforms, E. coli, Salmonella, Shigella, Staph. aureus and yeast and moulds were not detected in any of the samples. The cow’s milk yoghurt prepared with 25% unsprouted soymilk had higher contents of caproic, caprylic, and lauric acids over the control samples. The yoghurt prepared with 25% sprouted soymilk had higher concentrations of margaric, palmitoleic, proprionic, tricosylic, tridecylic and vaccenic acids as compared to the control as well as the unsprouted samples. These free fatty acids might have contributed to the typical flavour of soy blended cow’s milk yoghurt. The cow’s milk yoghurt blended with 25% of unsprouted and sprouted soy milk enjoyed identical panel acceptance for the appearance, colour, body and texture, and flavour characteristics indicating that soy milk could be successfully blended with cow’s milk up to 25% in yoghurt without affecting its sensory properties. However, the cow’s milk yoghurt was more preferred for its taste as compared to the soy milk blended yoghurts. Cow’s milk yoghurt blended with 25% soy milk had the ‘Best Before End’ of 5d at refrigeration temperature.ThesisItem Open Access EFFECTS OF BLACK RICE EXTRACT ON QUALITY CHARACTERISTICS OF DUCK MEAT NUGGETS(College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, 2022-01) SAIKIA, KALPITA; Laskar, Saurabh KumarDuck meat nuggets were prepared by incorporating three different concentrations (0.5%, 0.9% and 1.3%) of black rice ethanol extract (BREE) and other non-meat ingredients to find out the best formulation which can be stored for a reasonable time at refrigeration temperature without affecting their physico-chemical, organoleptic and microbiological qualities. Nuggets were cooked by two different methods, i.e. steam cooking and oven cooking. The formulations prepared in the steam cooking method were CS (0% BRE), T1S (0.5% BRE), T2S (0.9% BRE) and T3S (1.3% BRE) and formulations prepared in the oven cooking method were CD (0% BRE), T1D (0.5% BRE), T2D (0.9% BRE) and T3D (1.3% BRE). A total of five batches of nuggets of each formulation were prepared, and different quality parameters were evaluated. In oven cooking nuggets were cooked in a preheated hot air oven at 120°C till the internal temperature reached 75 ± 2°C, Steam cooking nuggets were done in a cooking vat at 80ºC for 45min. After that, these were packed in food-grade polyethylene bags, stored under refrigeration temperature and evaluated for various quality traits viz., Water Holding Capacity (WHC), pH, Water activity (aw), Thiobarbituric acid (TBA) value, Total Plate Count (TPC), Total Viable Psychrophilic Bacterial Count (TVPBC),Coliform count, Yeast and Mould count, Staphylococcus count, Antioxidant activity, Colour Profile on 1st, 5th, 10th and 15th days of storage. In addition, Emulsion Stability, Cooking Loss, Proximate Composition, Organoleptic qualities, and Texture Profile of the products were estimated on the day of production (1st day). The production cost of duck meat nuggets were also calculated to find out the best and most economic formulation. Emulsion stability (ES), Cooking loss and proximate composition of duck meat nuggets did not show significant (P > 0.05) differences between control and Black Rice Extract treated products both in steam cooking and oven cooking. The pH values did not differ significantly between the treated and control formulations in both the cooking methods. However, there was a significant (P 0.05) among the treatments and control formulations in either of cooking methods. A significant (P 0.05) differences were observed between control and treated products in terms of hardness, fracturability and chewiness in both the cooking method, However, springiness, cohesiveness and resilience values of texture profile showed significant (P < 0.01) differences between the product groups. The results of colour profile studies showed that the redness (a*) value increased significantly (P < 0.01) with the increased incorporation of Black Rice Extract, however during storage, the value decreased significantly in all the formulations. The lightness (L*) and Yellowness (b*) values decreased significantly (P < 0.01) with the incorporation of BRE, although, the b* value ii decreased, and the L* value increased significantly in all the formulations & in both the cooking methods during storage periods. The incorporation of higher concentrations of black rice extract resulted in higher DPPH free radical scavenging activity. During storage (up to 15 days) it had shown a significant decreasing trend of antioxidant activity in all the formulations and in both the cooking methods. The higher concentrations of black rice extract resulted in higher total phenolic content. The taste panel evaluation studies in respect of overall acceptability scores of duck meat patties involving all the eating quality parameters revealed that the 0.9% BRE treated products (T2) had the highest overall acceptability scores. Though, the panel scores of nuggets recorded for all other treatment groups were found acceptable. Estimation of production cost of duck meat nuggets indicated that T3 formulation products were more economical than the control and other treated products. Based on the results obtained in the study, it might be concluded that duck meat nuggets could be prepared satisfactorily on the addition of up to 1.3% concentration of BRE and can be stored safely up to 10 days under refrigeration temperature.ThesisItem Open Access DEVELOPMENT OF LOW CALORIE FAT REDUCED FERMENTED DAIRY PRODUCT(College of Veterinary Science, Assam Agricultural University Khanapara, Guwahati-781022, 2017-07) Bania, PriyankaA study was carried out to develop a low calorie fat reduced fermented dairy product. The experiments were conducted in the laboratories of the Department of Livestock Products Technology and the All India Coordinated Research Project on Post-Harvest Engineering and Technology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781 022. Strain NCDC 263 obtained from the National Dairy Research Institute, Karnal, Haryana-132 001 was used as starter culture. Low calorie, fat reduced misti dahi was prepared by replacing sucrose at 25, 50, 75 and 100% with either natural sweetener – honey or with artificial sweetener - sucralose. Effect of sugar replacement on pH and lactic acid content, proximate composition, microbiological quality, organoleptic properties and calorific value of misti dahi was studied. Acid production capacity of the starter culture showed decreasing values along with a corresponding increase in pH values of the dahi samples in the treatment groups. Results of the study on the proximate composition of misti dahi with varied concentrations of sugar, honey or sucralose revealed a gradual decrease in protein and total solids contents while an increase in moisture content was noted. Fat content of the products showed variable results. Total viable count showed an increase in honey added misti dahi while sucralose added products showed a gradual decrease in TVC. Yeasts and mould count was found to be below the minimum countable number of 25 per plate for all the treatment groups including the control. Coliform organisms were not detected in any of the samples. Sensory evaluation of the low calorie, fat reduced misti dahi samples was done for various eating quality attributes like appearance, colour, body and texture, flavour and taste by a semi-trained panel. Results of the study showed that the misti dahi containing 25% honey was rated best for flavour, taste and overall acceptability. The samples of the control group enjoyed superior ratings for appearance and body and texture. Samples of the T8 group scored the lowest ratings for overall acceptability. Calorific value of all the treatment groups was found to be lower than that of the control group (97.33±1.33). Among the treatment groups, the least calorific value was calculated in the samples of T8 group (56.26±2.07) and among the treatment groups the samples of the T1 group had the highest calorific value (94.80±3.63). On the basis of low fat content of 2.96±0.22% and superior eating quality characteristics, treatment group T1 containing 25% honey and 75% sucrose is recommended and a suitable protocol for commercial production of misti dahi has been proposed.ThesisItem Open Access DEVELOPMENT OF CHICKEN JALEBI-A READY-TO-EAT MEAT SNACK(College of Veterinary Science, Assam Agricultural University Khanapara, Guwahati-781022, 2017-07) Doley, Preeti; Hazarika, M.The study was conducted in the department of LPT, Assam Agricultural University, Khanapara. Chicken jalebis were prepared by incorporating 23% non meat ingredients ( Black gram flour, Bengal gram flour, corn flour, rice flour, semolina flour) at different proportions with 55% chicken (Broiler meat) to find out the best formulation without affecting the physico-chemical, microbial and organoleptic qualities of the product. A total of five batches of chicken jalebi comprising of three different formulations in each batch were prepared. Non meat ingredients were fermented for 24hrs with curd at room temperature. Chicken was collected from local market, deboned, minced and processed. Different formulations of chicken jalebi batter were prepared by mixing broiler minced meat with fermented non meat ingredients, spices, oil, salt and ice to form a stable emulsion. The batter is then stuffed in a conical shaped plastic packet and pressed in such a manner to give a jalebi shape and then fried in refined sunflower oil at 180±5ᵒC for 5-10mins. One part of the chicken jalebis was immersed in tomato sauce, prepared from tomato magi sauce with little modification and other part was kept as such and then different parameters such as % cooking loss, emulsion stability, pH, proximate composition, organoleptic qualities, bacterial quality, including cost of production were evaluated. The results of the investigation were summarised as follows: Emulsion stability of chicken jalebi incorporated with different non meat ingredients (Black gram flour, Bengal gram flour, corn flour, rice flour, semolina flour) were found to be highly stable. Percent cooking loss was found to be highest in T1 sample incorporated with bengal gram flour, black gram flour and corn flour and lowest in T2 sample with black gram flour, bengal gram flour, rice flour and corn flour. The percentages of moisture, fat, protein, ash were found to decrease with addition of sauce. Percent sauce absorption was found to be highest in T1 sample. The result with respect to pH of chicken jalebi has shown that T2 has the lowest pH. The pH decreased with addition of tomato sauce which is acidic in nature. The bacterial counts (TVC) at 0 hr was found to be nil in all treatments groups, however, after 24hrs of storage at room temperature, significant growth was recorded to extent of 101 cfu/g and the highest growth was recorded in T1 samples with sauce. Sensory evaluation revealed that T2 sample with sauce added was highly preferred when compared to other products. The cost of production when calculated, it was found that T1 without sauce was the cheapest (Rs.223.00) followed by T2 without sauce (Rs. 224.00), T3 without sauce (Rs. 225.00), T1 with sauce (Rs. 239.00), T2 with sauce (Rs. 240.00) and T3 with sauce (Rs 241.00)/Kg. The study revealed the fact that chicken jalebi which is an innovative meat snack may be successfully prepared with right proportion of meat and non meat ingredients to fulfil the demand of the meat consumers.ThesisItem Open Access EFFECTS OF DIFFERENT SMOKING METHODS ON CERTAIN QUALITY ATTRIBUTES OF PORK SAUSAGE(College of Veterinary Science, Assam Agricultural University Khanapara, Guwahati-781022, 2017-07) Bhuyan, Debajit; Das, AnkurAn experiment was conducted by employing conventional as well as application of commercial liquid smoke @ 3%, 5% and 7% to produce smoked pork sausages with the best eating and keeping quality attributes. The sausages were prepared as per a predesigned programme of work. Altogether 5 batches of sausages were prepared and these were evaluated on 1st, 5th, 10th and 15th days of storage for various important quality indicating parameters including the estimation of production cost. The highest ES (ml of oil/100g emulsion) was recorded for the control and T1 groups (1.88±0.12) of sausages while the lowest ES (3.2±0.10) was observed in the T2C formulations. In terms of % CL, the T1 formulation recorded the highest (16.42±0.52) while the lowest values were recorded for the control formulation (5.58±0.46). Statistical analysis of the data showed highly significant differences (p<0.01) among the treatments for both the parameters. The control and T1 formulation recorded the lowest pH (nonsignificant) in the sausage emulsion, while finished sausages of T1 formulation recorded the lowest pH with significant difference (p<0.05) within the group. The mean aw recorded on the 1st day of production in the sausage emulsion and the finished sausages were almost static and did not reveal any significant difference, while there was a gradual increase in the TBARS values of the finished sausages from the beginning till the end of the experiment. The lowest TBARS values were recorded by sausages of T2A and T2C formulation (0.24±0.001) on 15th day of storage with significant difference (p<0.01) amongst the treatments and also within the various days of preservation. The highest % moisture, % CP, % EE and % TA was recorded for T2C (64.16±0.31), T2A (19.57±0.54), T1 (21.66±0.98) and control (1.29±0.12) group of sausages. The % moisture and % EE content of the sausages differed significantly (p<0.01) while no significant differences (p>0.05) were observed in terms of % CP and % TA content. In terms of TPA analysis, the highest scores for hardness, chewiness, cohesiveness and resilience were recorded by the sausages of T1 formulations, while the highest scores for fracturability and springiness were recorded by the sausages of control and T2B formulation. T1 formulation also recorded highest shear force values (1.023±1.75) with significant different (p<0.05) amongst the treatments. All the sensory parameters like appearance, colour, flavour, texture, juiciness and overall acceptance of the control as well as the treated sausages exhibited a declining trend from the very 1st day till the end of the experiment. It was observed that beyond 5th day of refrigerated storage, all the sausage samples failed to earn satisfactory ratings from the panel members. However, the CS and LS treated sausages scored comparatively better than those from control group. Statistical analysis of the data on sensory parameters reveled significant differences (P<0.01) in the control as well as in the treated formulations at different periods of storage. The mean TVPC and TPC (log cfu/g) of the smoked pork sausages exhibited significant differences (P<0.01) between the treatment groups and also amongst the storage periods while in terms of Y&M counts no significant differences were observed. There was a gradual increase in the mean TVPC, TPC and Y&M counts of the sausages with the progress of the storage periods. The mean TVPC counts on 15th day of study were recorded to be 4.17±0.02, 5.43±0.06, 5.24±0.04, 5.31±0.01 and 5.23±0.01 for control, T1, T2A, T2B and T2C sausages, while the TPC and Y&M counts for T1 sausages were found to be below the countable range throughout the storage periods. The colititre count in respect of pork sausages prepared with conventional smoking as well as by 8 using liquid smoke at various concentrations did not reveal any growth for the entire period of study. Though the smoked pork sausages were found to be within the acceptable limit from the lipid oxidation (TBARS Values) and microbiological safety point of view till 15th day of refrigerated storage; from the sensory analysis, it was evident that panel members almost rejected the sausages irrespective of any treatments employed after 5th day of storage. The cost of production of smoked pork sausages estimated on the basis of prices of raw materials, cost of smoking, other non-meat ingredients, processing and ancillary costs etc. revealed that cost of sausages prepared with conventional smoking was more expensive than those prepared with liquid smoke at various concentrations (Rs. 378.00 V/s Rs. 330.00, 332.00, 334.00 and 336.00 per 1 kg).