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Assam Agricultural University, Jorhat

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Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.


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  • ThesisItemOpen Access
    (2016) Gogoi, Bebi; Ojha, N. J.
    A field experiment entitled “Integrated nutrient management in yellow sarson - greengram cropping system under rainfed condition” was carried out at the Instructional-cum-Research farm of Assam Agricultural University, Jorhat during two consecutive rabi (Oct-Feb) followed by summer (Feb-May) seasons of the year 2017- 2018 and 2018-2019. The experiment was laid out in randomized block design for first crop and split plot design for second crop with three replications. The eight INM practices viz., 100% RDF (60-30-30 kg/ha N-P2O5-K2O) (Y1), 100% RDF + biofertilizer consortium (Y2), 75% RDF + 25% N through vermicompost (Y3), 75% RDF + 25% N through vermicompost + biofertilizer consortium (Y4), 50% RDF + 50% N through vermicompost (Y5), 50% RDF + 50% N through vermicompost + biofertilizer consortium (Y6), 25% RDF + 75% N through vermicompost (Y7) and 25% RDF + 75% N through vermicompost + biofertilizer consortium (Y8) were applied to yellow sarson crop. In greengram crop the residual effect of the treatments applied to yellow sarson were allotted in main plots and two different integrated nutrient management practices viz., 100% RDF + biofertilizer consortium (G1) and 50% RDF + biofertilizer consortium (G2) in the sub plots. The soil of the experimental site was sandy loam in texture, acidic in reaction (pH 5.40 and 5.56), medium in organic carbon (0.69 and 0.72%), available N (274.86 and 290.75 kg/ha), available K2O (138.16 and 140.89 kg/ha) and low in available P2O5 (17.90 and 20.30 kg/ha) in the year 2017-18 and 2018-19, respectively. Experimental findings revealed that application of 75% RDF + 25% N through vermicompost + biofertilizer consortium (Y4) resulted in significantly higher growth as well as yield attributing characters like plant height, number of branches per plant, dry matter accumulation, crop growth rate, relative growth rate, number of siliquae per plant, length of siliqua, number of seeds per siliqua in both the years. The highest seed yield of 998.34, 1026.22 and 1012.28 kg/ha, stover yield of 2393.97, 2420.65 and 2407.31 kg/ha during 2017-18, 2018-19 and in pooled analysis, respectively, were recorded with treatment having 75% RDF + 25% N through vermicompost + biofertilizer consortium (Y4). The seed oil content of 36.40 and 36.97% and seed protein content of 13.27 and 13.44% were also recorded in Y4 in 1st and 2nd year, respectively. Similar effects of this treatment were also observed in respect of N, P and K content and uptake by both seed and stover. However, soil microbial population, microbial biomass carbon, phosphomonoesterase activity and fluorescein di-acetate hydrolase activity after harvest of yellow sarson were significantly higher in treatment having 25% RDF + 75% N through vermicompost + biofertilizer consortium (Y8). The crop recorded the highest gross return (` 56105 in 2017-18 and ` 57652 in 2018-19), net return (` 35407 during 2017-18 and ` 36954 during 2018-19) and benefit-cost ratio (2.71 during 2017-18 and 2.79 during 2018-19) with the treatment containing 75% RDF + 25% N through vermicompost + biofertilizer consortium (Y4). 7 In case of greengram, residual effect of 25% RDF + 75% N through vermicompost + biofertilizer consortium (Y8) resulted in significantly higher growth as well as yield attributing characters like plant height, number of branches per plant, dry matter accumulation, crop growth rate, number of pods per plant and number of seeds per pod in both the years. The effect of these was reflected in higher seed yield (849.56, 806.56 and 828.06 kg/ha in the year 2018, 2019 and in pooled analysis, respectively) and stover yield (2012.68, 1935.58 and 1974.13 kg/ha in 2018, 2019 and in pooled analysis, respectively) under the same integrated nutrient management practices. The maximum values of N, P and K uptake by seed and stover, soil microbial population, microbial biomass carbon, phosphomonoesterase activity and fluorescein di-acetate hydrolase activity after harvest of greengram were also observed under this treatment (Y8). However,direct application of 100% RDF + biofertilizer consortium (G1) brought about higher values in growth parameters, yield attributes, yield of seed (804.21, 724.68 and 764.45 kg/ha during 2018, 2019 and in pooled analysis, respectively) and stover yield (1830.89, 1763.80 and 1797.35 kg/ha during 2018, 2019 and in pooled analysis, respectively), protein content in seed (22.39 and 22.26% in 2018 and 2019 respectively), content and uptake of N, P and K by both seed and stover, soil microbial population, microbial biomass carbon, phosphomonoesterase activity and fluorescein diacetate hydrolase activity after harvest of greengram over 50% RDF + biofertilizer consortium (G2). The highest gross return (` 50726 in 2018 and ` 48922 in 2019), net return (` 33611 during 2018 and ` 31807 during 2019) and benefit-cost ratio (2.96 during 2018 and 2.86 during 2019) were observed under treatment Y8G1 containing 100% RDF + biofertilizer consortium (G1) + residue of treatment Y8 (25% RDF + 75% N through vermicompost + biofertilizer consortium). In regards to yellow sarson-greengram cropping system the highest yellow sarson equivalent yield (1678.57 and 1614.02 kg/ha in 2018 and 2019, respectively) were obtained by treatment Y4G1 containing 100% RDF + biofertilizer consortium (G1) + residue of treatment Y4 (75% RDF + 25% N through vermicompost + biofertilizer consortium). The highest gross return (` 93518 in 2017-18 and ` 89981 in 2018-19), net return (` 55705 during 2017-18 and ` 52168 during 2018-19) and benefit-cost ratio (2.47 during 2017-18 and 2.37 during 2018-19) of yellow sarsongreengram cropping system were observed under treatment Y4G1, containing 100% RDF + biofertilizer consortium (G1) + residue of treatment Y4 (75% RDF + 25% N through vermicompost + biofertilizer consortium). The performance of yellow sarsongreengram cropping system was assessed on the basis of yellow sarson equivalent yield, net monetary returns and B-C ratio. The application of 75% RDF + 25% N through vermicompost + biofertilizer consortium to yellow sarson and 100% RDF + biofertilizer consortium to greengram was the most beneficial combination compared to rest of the treatments.
  • ThesisItemOpen Access
    (AAU, Jorhat, 2018) Kalita, Pallabi; Dutta, Marami
    An investigation was carried out to study the pedogenic distribution of Fe and Al, the soil acidity components and to assess the relationship of pedogenic Fe and Al with soil acidity components under different land uses in Golaghat district of Assam. Five pedons were selected representing five land uses viz., Forest cover (P1), Paddy cultivation (P2), Tea plantation (P3), Bamboo plantation (P4) and Vegetable cultivation (P5) from Nambor Doigrung Reserve Forest, Borjan, Doria, Dergaon and Danichapori respectively. The dominant hue of soil colour was 10YR. Value ranged from 4 to 7 and chroma ranged from 1 to 6. Texture varied from sandy loam to clay loam in the surface and loam to clay in the sub-surface horizons. The structure of the soils varied from massive in the surface to sub-angular blocky to angular blocky in the subsurface. The clay content and bulk density increased with soil depth. The highest amount of organic carbon was recorded in A horizon of forest soil (P1) with 2.2 per cent. The pH were in acidic range in all the pedons and in all the cases ΔpH (pHKCl – pHH20) was negative. Among the exchangeable cations Ca2+ was the dominant followed by Mg²⁺, Na⁺ and K⁺. CEC ranged from 7.5 to 10.8 in the surface and 5.8 to 15.9 cmol (p⁺) kg⁻¹ in the sub-surface horizons. The percent base saturation generally tended to increase with depth with some exceptions in P1. Soils were classified as Typic Dystrudepts (P1, P3 and P4), Oxyaquic Hapludalfs (P2) and Aquic Udifluvents (P5). Dithionite extractable Fe (Fed) and Al (Ald) constituted the highest amount among the pedogenic iron and aluminium. Fed tended to increase with soil depth with few exceptions. On the weighted average, paddy soil (P1) recorded the highest Fed. Oxalate extractable iron (Feo), amorphous inorganic iron (Feo – Fep) was irregularly distributed in all the pedons. On the weighted average vegetable soil (P5) and paddy soil (P2) recorded highest (Feo) and (Feo – Fep) respectively. The distribution of (Fed – Feo) was irregular in all the pedons except P1. On the weighted average forest soil (P1) recorded the highest (Fed – Feo). The surface horizons recorded comparatively higher amount of pyrophosphate extractable iron (Fep) than the subsurface horizons in all the pedons. The amount of KCl extractable iron (FeKCl) was low which ranged from 0.001 to 0.002 per cent in all the pedons. The ammonium acetate extractable iron (FeNH4OAc) was below detectable limits in all the pedons. On the weighted average, Paddy soil (P2) recorded the highest dithionite extractable aluminium (Ald). Oxalate extractable aluminium (Alo), crystalline form of aluminium (Ald – Alo) and amorphous inorganic aluminium (Alo – Alp) followed inconsistent trend with soil depth whereas pyrophosphate extractable aluminium (Alp) decreased with soil depth. Bamboo soil (P4) recorded the highest Alo, bamboo soil (P4) and vegetable soil (P5) recorded highest Alp. Bamboo soil (P4) recorded highest (Alo – Alp) and forest soil (P1) recorded highest (Ald – Alo). The amount of ammonium acetate extractable aluminium (AlNH40AC) at pH 4.8 was low but was higher than that extracted by KCl solution. Profile weighted mean of forms of acidity under various land uses depicted that the paddy soil (P2) exhibited maximum extractable, non-exchangeable and hydrolytic acidity, tea soil (P3) exhibited maximum total acidity, exch. H+, exch. Al3+ and exchange acidity and bamboo soil (P4) exhibited maximum pH dependent and total potential acidity. It was observed that the soils under forest cover (P1) and vegetable cultivation (P5) exhibited lower acidity compared to other land uses in the present study. Principal component analysis of the 27 soil characters revealed that different forms of Fe and Al contributed towards development of soil acidity irrespective of land use. Among the physico-chemical parameters clay contributed positively and significantly and pH (pHH2O and pHKCl) contributed negatively and significantly towards soil acidity.
  • ThesisItemOpen Access
    (2018) Mudoi, Mridupaban; Mishra, P.
    India is a vast country with many states that have a population of more than 1.3 billion. Democratically governing a country of this size necessitates several tiers of government. Keeping this in view Panchayati Raj Institutions have been introduced under the 73rd Amendment Act of the Constitution of India. Accordingly in view of the historic Constitution (73rd Amendment) Act, 1992, the Assam Panchayati Raj Act, 1994 was enacted and came to effect from 5th May, 1994. Preparing the Panchayat members for their new roles as local decision-makers, calls for education and training on a massive scale, for which appropriate tailor made training content, methods and tools are needed. The study was conducted with a view to measure the effectiveness of training programmes conducted by Extension Training Centre, Jorhat and to delineate the factors affecting training transfer by PRI members and the resultant transfer outcome. A purposive cum random sampling technique was followed for selection of total 120 nos. of respondents. Only 2 districts namely Jorhat and Golaghat were selected for the present study. In this study, first a database of the training programmes conducted by ETC, Jorhat for 3 years (2013-14 to 2015-16) was developed. The database of the training programme revealed that maximum numbers of training programmes were conducted during the period 2013-14 (140 nos.), followed by 2015-16 (77 nos.) of which majority (51.77%) of the trainees were female and belonged to OBC category (44.26%). Maximum (72.22%) numbers of training programmes were conducted for the trainees of Jorhat district and also majority (51.04%) of the training programmes were conducted on campus. The findings of this study revealed that majority (72.50%) of PRI members were in between 31 to 50 years and 11.67 per cent of PRI members were graduate followed by 40.83, per cent of PRI members belonged to OBC caste. Majority (56.67%) of the trainees were female with the experience of working in PRI ranging from 4 to 8 years (73.33%). Majority (84.17%) of the trainees were belonged to nuclear family. A healthy percentage (74.17%) of the PRI members possessed moderate level leadership behaviour. The study also showed that majority (78.33%) of the respondents possessed moderate level cosmopoliteness and have moderate level decision making ability. Regarding the effectiveness of training programmes in terms of perceived usefulness, knowledge gained and skill developed as a result of training programme, majority (75.83%) of the trainees opined that the training was moderately useful. On the other hand, 75.00 per cent trainees perceived that there was moderate gain in knowledge as result of the training programme and there were 77.50 per cent of the trainees perceived that the skill was moderately developed. Moreover, in terms of its perceived usefulness, the topic on “Community participation in Swachh Bharat Mission” (WMS= 2.79) was ranked “first”.In terms of perceived knowledge gained, the topic on “Pradhan Mantri Gram SadakYojana” (WMS= 2.71) was ranked “first”. Besides, effectiveness of training programme regarding its perceived skill developed, the topic, “Panchayati raj institution accountant software” (WMS= 2.90) was given “first” rank by the respondents. Moreover, “peer support” (WMS= 4.67) and “Strategic link” (WMS= 4.67), followed by “Supervisor support” (WMS= 4.64) and “General work environment” (WMS= 4.64) were considered to be major factors of training transfer and “Community participation under Swachh Bharat Mission reduces open defecation” (WMS= 4.68) followed by “MIS under MGNREGS improves decision making ability and communication” (WMS=4.68), “RKVY increases total production and reduces yield gap of important crops” (WMS= 4.68), “role played by GP in increasing livestock production and management increases nutritional status of the villagers” (WMS= 4.63), were considered to be the major training outcome of the training programmes. Findings of correlation analysis showed that age (r = 0.15*), work experience (r = 0.21**) and decision making ability (r = 0.19**) had positive and significant relationship with effectiveness of training programmes. However, It can be further seen from the analysis that the relationship between leadership behaviour (r= -0.15*) and effectiveness of the training programme were negatively significant.
  • ThesisItemOpen Access
    (AAU, Jorhat, 2018) GOGOI, PRITISMITA; Deka Baruah, Manoshi
    The present study entitled “Effect of selected social media on development of youth of Assam” was carried out with the following objectives: 1.To study the profile of the respondents. 2. To explore the reasons of using selected social media by the respondents. 3. To find out the extent of using selected social media by the respondents. 3. To analyse the perceived effect of social media on development of the respondents. Two districts were selected for the present study. From each of the selected districts two sub-division namely Jorhat and Sivasagar were selected randomly. From each of the sub-division six colleges were selected randomly. Equal number of respondents was selected from each of the selected colleges through simple random sampling. Thus total number of respondents was 120. Data were collected using structured interview schedule and analysed using appropriate statistical techniques viz., frequency, percentage, mean, standard deviation and chisquare. The data revealed that 38.33 per cent of the respondents belonged to age group of 19-21 years, majority (71.67%) were female, 59.17 per cent were from rural residency, 54.17 per cent were UG students, salaried job was the main occupation of the family for 55.83 per cent of respondents, for 58.33 per cent of the respondents the family income was between Rupees Twenty thousand to Fifty thousand. Findings further showed that they spent 2.30 hours in social media. Findings also highlighted that majority (94.17%) of the respondents used WhatsApp followed by Facebook (74.17%), YouTube (59.17%), Instagram (25.00%), Twitter (4.17%) and only 0.83 per cent respondents used LinkedIn. Data revealed that 43.33 per cent respondents commonly used three numbers of social media. 43.30 per cent respondents used WhatsApp most frequently. Most of the respondents (99.17%) used mobile phones for social media activities, 55.00 per cent used home network for social media connection. The data on reasons of using social media by the respondents revealed that communication with friends was ranked I followed by entertainment. It was found that education related area was discussed with teachers by 89.17 per cent respondents, general discussion was held with relatives by 67.50 per cent, entertainment with friends by 73.33 per cent and national issues generally discussed with different organization officials by 40.99 per cent respondents. Findings on frequency of using social media revealed that all the respondents use social media on daily basis and 40.00 per cent of the respondents spent more than 2 hours on social media. The overall effect of social media on development, percentage of respondents was higher (16.67%) in high category than low (15.00%) which might be assumed as positive effect of social media on development of the youth. Association between education and income of the family was highly significant with perceived effect of selected social media. Place of residence was also positively associated while age, time spent on social media and number of social media used have no significant association with perceived effect of selected social media.
  • ThesisItemOpen Access
    Shelf life of Khasi mandarin (Citrus reticulata Blanco) fruits as influenced by plant extracts, essential oils and natural coatings
    (AAU, Jorhat, 2018) Muzafary, Sayed Yusuf; Borthakur, P. K.
    The experiment was conducted during 2017-18 in the Post-harvest laboratory of the Department of Horticulture and Department of Plant Pathology, Assam Agricultural University, Jorhat. The objective of this investigation was to study the effect of plant extracts, essential oils and natural coatings on shelf life of Khasi mandarin fruits and also to determine the physico- chemical and organoleptic changes during storage. The experiment was taken up in two parts .In the first experiment in vitro pathological study was taken up to test the effect of selected plant extracts and essential oils against Penicillium digitatum (green mold). The results of in vitro studies revealed that, out of the various plant extracts 100% inhibition of Penicillium digitatum was observed in Neem extract and cinnamon extract treatments. Similarly amongst the oils, clove oil, Thyme oil and lemongrass essential oil showed maximum inhibition (100%) of the fungi. The two of the best plant extracts and essential oils were selected for next experiment. In the second Experiment, Khasi mandarin fruits were treated with two best Plant extracts and essential oils (as obtained in the first experiment) alone or in combination with two natural coatings viz. Aloe vera gel and chitosan. After the treatment the fruits were wrapped in perforated 50 micron polyethylene bags and stored under ambient condition and various physicochemical and sensory evaluations were taken up across the storage period. The results revealed that during 20 days of storage period maximum decay loss was observed in the control treatment. On the other hand fruits treated with Bavistin, Neem extract and combination of Aloe vera gel + Neem extract treatments, no decay loss was observed during the 20 days of storage period. As regard the number of days taken for 50% decay of fruits; it was observed that the fruits treated with Bavistin treatment took the maximum number of days for 50% decay of fruits i.e.35 days followed by Neem extract treatment (33.66 days) and combination of Aloe vera gel + Neem extract (29.33days) treatments. Though Bavistin treatment recorded higher values with respect to physic-chemical and sensory evaluation; there was no significant difference between the Bavistin treatment and Neem extract treatment and also with the combination of Aloe vera gel (1%)+ Neem extract(10%) (in some of the observations). Since plant extracts are environment friendly and do not leave any chemical residue as against use of chemical fungicides (like Bavistin), use of Neem leaf extract and combination of Aloe vera gel (0.1%) + Neem extract(10%) can be advocated for enhancing shelf life of Khasi mandarin fruits.
  • ThesisItemOpen Access
    (AAU, Jorhat, 2018) Kalita, Upama; Das, Manashi Purkayastha
    Makhana, an underutilize aquatic crop of Nympheaceae family, has various medicinal properties but has not gain much attention in the field of processed products and marketing. Value added product from makhana can be envisaged; however development of suitable processing technique for the same is still lacking. The objective of the study is to develop nutritious ready –to-reconstitute mix formulation using makhana as the prime ingredient. Makhana seed was ground into flour which was found to contain high amount of carbohydrate (69.06%) and protein (~9.69%). Makhana flour was subjected to two processing techniques i.e. roasting (100o C for 1, 3 and 5min) and steaming (100o C for 10, 15, 30, 45 and 60 min) for improving resistant starch (RS) content. RS was found to be highest in S8 (steaming for 60 min), followed by S2 (roasting for 3min) and S3 (roasting for 5min). Though steaming improved the RS content in makhana flour upto 0.92%, however the off-odour of steamed samples made them organoleptically unacceptable. While roasting eliminated the off-odour of makhana and also improved the RS value (0.58% to 0.84%); wherein S2 (0.84%) had the highest overall acceptability. As such S2 was selected for formulating ready-to-reconstitute mix by adding it with fig and banana flour at different proportion .These formulations were reconstituted in water /milk for assessing rehydration ratio, viscosity and sensory analysis. Rehydration ratio and viscosity were found maximum in T9 (60% makhana, 30% fig,10% banana) followed by T8 (60% makhana, 10% fig, 30% banana).High viscosity and rehydration ratio in these formulations were attributed to the presence of high amount of fig and banana flours having high crude fiber (2.08 % in banana and 4.14 % in fig).All the formulations received high mean score for colour, appearance and texture, taste, flavor and overall acceptability except T1 (contain makhana flour as control). The comments from the panelist revealed that natural sweetness of fig and banana sufficed the need of any extraneous sweetener in the formulations excluding the control (T1), where makhana gave a bland taste. T8 (60% makhana, 10% fig, 30% banana) scored the highest overall acceptability and was thus found to be suitable for making ready-to-reconstitute mix. Hence, suitably makhana flour (roasting) can be blended with other fruits and vegetables for making convenient foods.
  • ThesisItemOpen Access
    (AAU, Jorhat, 2018) Koch, Parismita; Barooah, Mridula Saikia
    The consumer demand is increasing for bakery products having high nutritional value and potential health benefit. The primary objective of the study is to produce baked goods using partial substitution of fat with papaya pulp concentrate and wheat flour with buckwheat and defatted soya flour. Cookies and muffins were prepared with different composite flour treatments of refined wheat flour, buckwheat flour and defatted soy flour in the ratio of 80:10:10 (T1). 70:20:10 (T2) and 60:30:10 (T3). Papaya pulp concentrate was obtained after drying papaya pulp at 60°±2°C for a period of 60, 90 and 120 minutes. The pulp concentrate with 120 minutes of drying was selected which contained total soluble solid content (20.5 ⁰Brix) double than that of the fresh pulp. This papaya pulp concentrate was used at 20%, 30%, 40% and 50% levels for replacing fat during baking. The organoleptic evaluation using 9 point hedonic scale revealed that cookies from the three composite flour treatments with 30% level of fat replacement scored highest in all the sensory attributes while for muffins, the composite flour treatments with 40% level of fat replacement received the highest scores. The physico-chemical analysis indicated that cookies and muffins of composite flour treatment T1 had the lowest fat content whereas composite flour treatment T3 for both the products were higher in nutritional composition. The protein, fiber and ash content of cookies increased to 17.82 g/100g, 2.27 g/100g and 1.56 g/100g with DPPH inhibition % 60.13% respectively and fat content decreased to 19.37 g/100g in comparision to control with 23.82 g/100g. For muffins, the protein, fiber and ash content increased to 19.02 g/100g, 2.35 g/100g and 1.79 g/100g with DPPH inhibition % 61.07% respectively and fat content decreased to 13.84 g/100g in comparision to control with 18.77 g/100g. The shelf-life of papaya pulp concentrate with different treatments was upto 5 days after which visible growth appeared. The pulp concentrate with preservative stored in refrigerator had the least microbial count on fifth day. The shelf-life of cookies packaged in air tight container and HDPE packages were upto 90 days in regard to both microbial load and sensory evaluation. The muffins were acceptable up to 14 days after which visible growth was visible. The overall acceptability of the bakery products decreased with increase in storage period. Thus it can be concluded that use of composite flour and papaya pulp concentrate in baked foods causes increased overall nutritional quality, decreased fat content and thereby trans fat and calorie content.
  • ThesisItemOpen Access
    (AAU, Jorhat, 2018) Deka, Pampi; Saikia, Ananta
    Investigations were carried out at the Departments of Horticulture and the Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, during 2016-2018 on yoghurt developement from non-dairy plant sources like taro and tapioca. The yoghurts were prepared by infusing taro and tapioca in soymilk using bacterial cultures collected from the Depatment of Agricultural Biotechnology and isolates from commercial yoghurts. Isolated strains were identified as Streptococcus thermophilus PD5 MH569615, L. delbrueckii subsp. lactis PD7 MH569616 and L. brevis PD8 MH569617 for milk fermentation with the help of 16S rDNA gene sequencing. Those strains were phylogenetically similar with their related species. Through sensory evaluation of yoghurt samples, four yoghurts were selected as best and those samples were AB9 (1:9 taro-soy yoghurt; 1:1 S. thermophilus and L. delbrueckii subsp. lactis), CD19 (1:9 tapioca-soy yoghurt; 1:1 S. thermophilus and L. delbrueckii subsp. lactis), CDY (1:9 tapioca-soy yoghurt; 1:1 S. thermophilus and L. brevis), and CDZ (1.5:8.5 tapioca-soy yoghurt; 1:1 S. thermophilus and L. brevis). The selected yoghurt samples were subject to physio-biochemical and microbiological analysis which revealed that yoghurt AB9 contained the highest protein (6.47 g 100 g-1), fibre (0.25 g 100 g-1), viscosity (684.03 cP); but with the lowest moisture (81.73%), carbohydrate (3.66 g 100 g-1), fat (0.28 g 100 g-1), acidity (0.34%) and pH (4.20). On the basis of sensory evaluation and physio-biochemical properties, AB9 (1:9 taro-soy yoghurt; 1:1 S. thermophilus and L. delbrueckii subsp. lactis) was considered as the best. The microbiological examination revealed that yoghurt had a shelf life of 6 days with Lactobacilli count of 6.63 log cfu mL-1, S. thermophilus count of 6.84 log cfu mL-1 with absence of coliform bacteria.
  • ThesisItemOpen Access
    Evaluation of Acetic Acid Bacteria for Production of Organic Vinegar from Chepa guti, a waste by product of rice based alcoholic fermentation
    (2018) Neog, Noopur Ranjan; Barooah, M.
    Chepa guti, a byproduct of the Xaj-brewing process is the lees left behind after the liquid is separated from the fermented product. The technological advance in the field of rice brewing is expected to witness an upsurge in brewing plant and an increase generation of this byproduct. Chepa guti is specifically seen to retain starch and fermentable sugars which can be used to produce down stream products like acetic acid. Chepa guti collected from different localities were used as a source for isolation of acetic acid bacteria. Three isolates that matched acetobacter species on biochemical level were further characterized at the molecular level through 16SrDNA gene sequencing and identified as Acetobacter indonesiensis, Acetobacter spp. and Acetobacter tropicalis. The collected chepa guti was initially characterized at the biochemical level and subjected to hydrolysis with commercial alpha-amylase at different concentration for generating maximum amount of reducing sugar. The aamylase at 0.3 per cent concentration in 1:1.5 substrate dilution (substrate : water) along with fungal culture Amylomyces rouxii ABT82 (NCBI KP790015) at 48 hours of incubation time produced maximum reducing sugars (73.41 mg 100mL-1). Simultaneous saccharification and fermentation using the yeast isolate Saccharomyces cerevisiae ADJ 5 (NCBI KX904349) produced 8.19 % ethanol. This substrate was used to produce acetic acid by inoculating pure culture of isolated acetic acid bacteria viz., Acetobacter indonesiensis , Acetobacter spp , Acetobacter tropicalis along with a control inoculated with reference strain Acetobacter aceti ATCC 15973 and treatment combination. Acetic produced by the pure culture of Acetobacter tropicalis was significantly higher in terms of acetic acid content of (9.08 %). It had pH (2.68), residual alcohol of (0.52 %), TSS of (0.91 ˚Brix), residual reducing sugar of (0.25 mg 100 mL-1) and protein content of (68.09 μg 100 mL-1). The LC-MS analysis of the produced acetic acid showed the presence of compounds like O-Phosphoserine, 2',3'-Dideoxyadenosine, Phenylalanine, 2-(4-Hydroxyphenyl) propionic acid, Creatine, N-Tigloylglycine, S-Sulforaphene, Triethyl phosphate, Metazachlor-OXA, Histidinol, Indole, Indoline, L-verbenone, Indole-3-carbinol, DL-Pipercolic acid, 1-Aminocyclopropane carboxylic acid. The Acetobacter tropicalis isolate was used in the scale up process where acetic acid content of (11.26 %) was achieved by increasing the inoculum size. The study reveals the potential of native acetic acid bacteria and development of a technology to produce organic acetic acid from bio-waste. The study was successful in isolating and identifying native acetic acid bacteria in Chepa guti and also was able to standardize the production of vinegar from the biowaste.