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Open Access
MORPHO-BIOCHEMICAL CHARACTERIZATION OF ROUGH LEMON (Citrus jambhiri Lush.) OF ASSAM
(2019-07) Pathak, Purnima; Khangia, B.
Rough lemon (Citrus jambhiri Lush.), commonly known as ‘Gol Nemu’ is an underutilized citrus fruit of Assam. It is mostly grown as backyard crop in homestead garden. The fruit is a rich source of vitamins, minerals, flavonoids, limonoids etc. It is polyembryonic in nature and highly cross pollinated. Most rough lemon plants are of seedling origin in the region and thus tend to exhibit a wide range of variability in terms of morphological and biochemical parameters. Therefore, an investigation was undertaken during 2016-2017 on ‘Morpho-biochemical characterization of rough lemon (Citrus jambhiri Lush.) of Assam to study the existing variability. One district in each of the six agro climatic zones was chosen and five plants were selected in each district, comprising of thirty plants. Wide variability was observed among the selected rough lemon accessions for qualitative characters of tree, leaf, flower, fruit and seed. Four different fruit shapes were recorded viz. spheroid, obloid, obovoid and ellipsoid. Wide variations in pulp colour i.e. ivory white, orange, orange-red, yellow were recorded in the selected rough lemon. Cluster analysis of 45 qualitative and 25 quantitative characters using SPSS resulted in grouping of the rough lemon accessions into three broad groups. Group I consisted of 17 accessions (AR01T1, AR01T2, AR01T3, AR02T1, AR02T2, AR02T3, AR02T4, AR03T2, AR03T3, AR04T4, AR05T1, AR05T2, AR05T3, AR05T4, AR06T2, AR06T3, AR06T5) of all locations. Group II consisted of six accessions (AR01T5, AR03T1, AR03T4, AR03T5, AR04T1, AR06T1). Group III consisted of seven accessions (AR01T4, AR02T5, AR04T2, AR04T3, AR04T5, AR05T5, AR06T4). No groups were formed based on geographical location indicating that qualitative and quantitative traits were largely influenced by genetic factor. The quantitative characters of flower, leaf and fruit showed significant variation among the rough lemon accessions. The maximum fruit weight was recorded in accession number AR02T5 (144.34 g) and the minimum was recorded in AR03T1 (17.36 g). In terms of biochemical constituents, the highest TSS was recorded in accession number AR06T4 (8.87 °B) and the lowest was recorded in AR02T1 (6.13 °B). The highest TSS-acid ratio was recorded in accession number AP06T4 (2.12) and the lowest was recorded in AR02T1 (1.00). HPLC quantification of limonin showed significant variations among the rough lemon accessions which ranged from 10.42 to 24.07 mg/100ml. Among the 30 rough lemon accessions, two main groups were recognized based on 12 biochemical constituents with strong genetic similarity within a location. All the morphological quantitative traits i.e. fruit length, fruit diameter, rind thickness, seeds per fruit, seed weight, juice content, juice per cent showed significant variation among different locations. Significant differences among the locations were observed with respect to biochemical constituents except essential oil content. The highest TSS, total sugar, TSS-acid ratio were recorded in location L6 (Cachar) and the lowest value was recorded in location L4 (Biswanath). Present study on propagation of rough lemon through seed showed an average germination percentage of 87.67 % and air layering recorded a success percentage of 92.11%. However, propagation through stem cutting was found to be comparatively difficult with moderate success percentage (79.11%). Three elite types i.e. AR03T1, AR06T1 and AP06T4 were identified in terms of high overall acceptability (>8), TSS-acid ratio (>2.00), less seed content (≤10 per fruit), low limonin content, high essential oil (>4%), high ascorbic acid and antioxidant activity (>80mg/100ml juice) and thin to medium rind thickness.
Open Access
HEAT UNIT INDEXING OF GARDEN PEA IN RELATION TO CLIMATE SHIFT AND NUTRIENT MANAGEMENT
(2019-07) Sangma, Trudy Tengse A.; Saikia, Luchon
An experiment was conducted consecutively during 2016-17 and 2017-18 in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat to study the “Heat unit indexing of garden pea in relation to climate shift and nutrient management”. The experiment consist three treatments viz., variety (main), fertility management level (sub) and sowing date (sub-sub) laid out in split plot design with random allocation and replicated thrice. The main treatment consisted Arkel(V1), A1(V2), DS-10(V3) and GS-10(V4); sub treatment was comprised of 5t FYM, 10-46-0 kgha-1 (F1), 10t FYM, 10-46-10 kgha-1 (F2), 10t FYM, 20-46-20 kgha-1 (F3) and 10t FYM, 30-46-30 kgha-1 (F4) and sub-sub treatment was dates of sowing: 10th October (S1), 24th October (S2), 7th November (S3), 21st November (S4), 5th December (S5) and 20th December (S6). Growth, yield attributes, soil related and quality characters viz., plant height(cm), days to 50% flowering, pod plant-1, pod length (cm), pod diameter (cm), seed pod-1, shelling (%), pod yield (tha-1), duration (days), growing degree days, root nodules plant-1, total plant nitrogen (%), total plant phosphorus(%), total potash (%), TSS (0 Brix), crude protein (%), soil organic carbon (%), soil available nitrogen (kgha-1), soil available phosphorus (kgha-1), soil available potash (kgha-1) and soil pH have responded significantly due to treatments as well as their interactions, except pH. Variety evidently produced significant effect on growing degree days (GDD) and results showed V4>V3>V2>V1 with requirement of 955, 948, 933 and 833 GDD for 2016-17 and similarly 958, 949, 942 and 825 GDD. The maximum duration was reported as 76.00days in V4F with (1,2,3,4) and S( with 3,4,5). Duration was closely associated with degree days by sowing date had indicated significant duration among varieties, least with V1(58.73days), to maximum in V4(72.30days). Fertility level had a range of maturity at 68.08 to 68.29days. Sowing dates showed significance as 911(S1), 915(S2), 915(S3), 915(S4), 916(S5) and 918(S6) during 2016-17 and the GDD was found significant as S1
Open Access
MORPHO-BIOCHEMICAL CHARACTERIZATION OF ROUGH LEMON (Citrus jambhiri Lush.) OF ASSAM
(2019-07) Pathak, Purnima; Khangia, B.
Rough lemon (Citrus jambhiri Lush.), commonly known as ‘Gol Nemu’ is an underutilized citrus fruit of Assam. It is mostly grown as backyard crop in homestead garden. The fruit is a rich source of vitamins, minerals, flavonoids, limonoids etc. It is polyembryonic in nature and highly cross pollinated. Most rough lemon plants are of seedling origin in the region and thus tend to exhibit a wide range of variability in terms of morphological and biochemical parameters. Therefore, an investigation was undertaken during 2016-2017 on ‘Morpho-biochemical characterization of rough lemon (Citrus jambhiri Lush.) of Assam to study the existing variability. One district in each of the six agro climatic zones was chosen and five plants were selected in each district, comprising of thirty plants. Wide variability was observed among the selected rough lemon accessions for qualitative characters of tree, leaf, flower, fruit and seed. Four different fruit shapes were recorded viz. spheroid, obloid, obovoid and ellipsoid. Wide variations in pulp colour i.e. ivory white, orange, orange-red, yellow were recorded in the selected rough lemon. Cluster analysis of 45 qualitative and 25 quantitative characters using SPSS resulted in grouping of the rough lemon accessions into three broad groups. Group I consisted of 17 accessions (AR01T1, AR01T2, AR01T3, AR02T1, AR02T2, AR02T3, AR02T4, AR03T2, AR03T3, AR04T4, AR05T1, AR05T2, AR05T3, AR05T4, AR06T2, AR06T3, AR06T5) of all locations. Group II consisted of six accessions (AR01T5, AR03T1, AR03T4, AR03T5, AR04T1, AR06T1). Group III consisted of seven accessions (AR01T4, AR02T5, AR04T2, AR04T3, AR04T5, AR05T5, AR06T4). No groups were formed based on geographical location indicating that qualitative and quantitative traits were largely influenced by genetic factor. The quantitative characters of flower, leaf and fruit showed significant variation among the rough lemon accessions. The maximum fruit weight was recorded in accession number AR02T5 (144.34 g) and the minimum was recorded in AR03T1 (17.36 g). In terms of biochemical constituents, the highest TSS was recorded in accession number AR06T4 (8.87 °B) and the lowest was recorded in AR02T1 (6.13 °B). The highest TSS-acid ratio was recorded in accession number AP06T4 (2.12) and the lowest was recorded in AR02T1 (1.00). HPLC quantification of limonin showed significant variations among the rough lemon accessions which ranged from 10.42 to 24.07 mg/100ml. Among the 30 rough lemon accessions, two main groups were recognized based on 12 biochemical constituents with strong genetic similarity within a location. All the morphological quantitative traits i.e. fruit length, fruit diameter, rind thickness, seeds per fruit, seed weight, juice content, juice per cent showed significant variation among different locations. Significant differences among the locations were observed with respect to biochemical constituents except essential oil content. The highest TSS, total sugar, TSS-acid ratio were recorded in location L6 (Cachar) and the lowest value was recorded in location L4 (Biswanath). Present study on propagation of rough lemon through seed showed an average germination percentage of 87.67 % and air layering recorded a success percentage of 92.11%. However, propagation through stem cutting was found to be comparatively difficult with moderate success percentage (79.11%). Three elite types i.e. AR03T1, AR06T1 and AP06T4 were identified in terms of high overall acceptability (>8), TSS-acid ratio (>2.00), less seed content (≤10 per fruit), low limonin content, high essential oil (>4%), high ascorbic acid and antioxidant activity (>80mg/100ml juice) and thin to medium rind thickness.
Open Access
HEAT UNIT INDEXING OF GARDEN PEA IN RELATION TO CLIMATE SHIFT AND NUTRIENT MANAGEMENT
(2019-07) Sangma, Trudy Tengse A.; Saikia, Luchon
An experiment was conducted consecutively during 2016-17 and 2017-18 in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat to study the “Heat unit indexing of garden pea in relation to climate shift and nutrient management”. The experiment consist three treatments viz., variety (main), fertility management level (sub) and sowing date (sub-sub) laid out in split plot design with random allocation and replicated thrice. The main treatment consisted Arkel(V1), A1(V2), DS-10(V3) and GS-10(V4); sub treatment was comprised of 5t FYM, 10-46-0 kgha-1 (F1), 10t FYM, 10-46-10 kgha-1 (F2), 10t FYM, 20-46-20 kgha-1 (F3) and 10t FYM, 30-46-30 kgha-1 (F4) and sub-sub treatment was dates of sowing: 10th October (S1), 24th October (S2), 7th November (S3), 21st November (S4), 5th December (S5) and 20th December (S6). Growth, yield attributes, soil related and quality characters viz., plant height(cm), days to 50% flowering, pod plant-1, pod length (cm), pod diameter (cm), seed pod-1, shelling (%), pod yield (tha-1), duration (days), growing degree days, root nodules plant-1, total plant nitrogen (%), total plant phosphorus(%), total potash (%), TSS (0 Brix), crude protein (%), soil organic carbon (%), soil available nitrogen (kgha-1), soil available phosphorus (kgha-1), soil available potash (kgha-1) and soil pH have responded significantly due to treatments as well as their interactions, except pH. Variety evidently produced significant effect on growing degree days (GDD) and results showed V4>V3>V2>V1 with requirement of 955, 948, 933 and 833 GDD for 2016-17 and similarly 958, 949, 942 and 825 GDD. The maximum duration was reported as 76.00days in V4F with (1,2,3,4) and S( with 3,4,5). Duration was closely associated with degree days by sowing date had indicated significant duration among varieties, least with V1(58.73days), to maximum in V4(72.30days). Fertility level had a range of maturity at 68.08 to 68.29days. Sowing dates showed significance as 911(S1), 915(S2), 915(S3), 915(S4), 916(S5) and 918(S6) during 2016-17 and the GDD was found significant as S1
Open Access
INTEGRATED NUTRIENT MANAGEMENT IN PAPAYA (Carica papaya L.)
(2019-07) MARAK, MINGNAM CH; Borthakur, P. K.
The present investigation on “Integrated nutrient management on papaya (Carica papaya L.) ” was carried out at the Horticulture Experimental Farm, Assam Agricultural University, Jorhat during the year 2017-2019. The objectives of the present investigation were to find the effect of different integrated nutrients on growth, development, yield, and post-harvest attributes of papaya and to standardize the integrated nutrient model for sustainable production of papaya. The experiment was laid out in randomized block design (RBD) with ten treatments and three replications. The observations were focused on growth characters, physiological attributes, yield, post-harvest attributes and soil status. The growth parameters viz. plant height (186.00cm), stem girth (45.92cm), number of leaf (40.17), total leaf area (10.63m2), number of lobes in leaf (8.50) recorded maximum value when plant were treated with T9:75% (NPK + Vermicompost + FYM + Consortia/plant) during both the year and in pooled analysis. Whereas, the same treatment showed earliness in the initiation of flowering (104.00days), increased number of flowers (82.00) and the lowest height for the first flower (58.67cm). Number of fruits per plant (79.40), average fruit weight (1.75kg), fruit length (25.25cm), fruit diameter (17.91cm), fruit yield per plant (118.68kg) and per ha (366.29t) were also found to be significantly higher in papaya plants supplied with T9:75% (NPK + Vermicompost + FYM + Consortia/plant). Regarding soil parameters, viz. N, P2O5, K2O, (229.22kg/ha, 50.19kg/ha and 128.89kg/ha) were higher in T9:75% (NPK + Vermicompost + FYM + Consortia/plant). Minimum physiological loss in weight (11.01%), titratable acidity (0.017%), higher content of total soluble solids (9.77°brix), total sugars (9.94%), reducing sugars (8.72%), ascorbic acid (23.01mg/100g pulp) and shelf life of fruit (10.17days) were also noted in same treatment i.e. T9:75% (NPK + Vermicompost + FYM + Consortia/plant). The data concerning the economics of present investigation revealed that the maximum net returns of Rs. 13326029.49 with a BCR (2.64) per hectare were obtained with application T9:75% (NPK + Vermicompost + FYM + Consortia/plant). On the basis of results obtained in present investigation, it is concluded that the application of T9:75% (NPK + Vermicompost + FYM + Consortia/plant) resulted in higher economic returns with improvement in soil and fruit quality of papaya cv. Taiwan Red Lady.
Open Access
Effect of indigenous methods of ripening on shelf life and quality of banana fruits
(AAU, Jorhat, 2019-07) Roy, Manuranjan; Langthasa, Supriya
The present investigation entitled “Effect of indigenous methods of ripening on shelf life and quality of Banana fruits” was carried out during 2017-2019 in thelaboratories, Department of Horticulture, B.N. College of Agriculture, AAU, Biswanath Chariali. The experiment was conducted with six different ripening methods with two varieties (Amritsagar and Chenichampa). The treatments were: ripening in covered pit with smoke (T1), ripening with ripe tomato (T2), ripening with paddy straw (T3), ripening in covered pit without smoke (T4), ripening with Calcium carbide(T5) and ripening naturally at room temperature (T6). The study was laid out in factorial CRD with three replications. Result of the study revealed marked variation in quality characters among the different treatments on ripening. Among the indigenous ripening methods, fruit ripenedwithripe tomato (T2) retained maximum TSS (21.75%), reducing sugar (5.12 %),total sugar (6.15%), moisture content (73.85%), calcium content (17.38 mg/100g), magnesium content (58.47 mg/100g) and potassium content (427.28 mg/100g). Similarly, fruit ripened with calcium carbide (T5) recorded highest acidity (0.347%) and phosphorous (74.81 mg/100g). The fruits ripened in covered pit without smoke exhibited maximum ash content (1.84%) and specific gravity (1.21%). The retention of ascorbic acid (5.19 mg/100g) was highest in T3 (paddy straw) treatment. Banana fruits ripened withcalcium carbideshowed rapid colour initiation within 2 days and full colour development stage in 2.5 days and followed by smoke which required 5 days for full colour development. Significant differences in terms of biochemical characters were observed among the banana varieties. The shelf life of Chenichampa banana was found to be 11.61 days as compared to Amritsagar (8.48 days). But among the treatment combinations, fruit of Chenichampa variety ripened naturally (control) showed maximum shelf life of 14.33 days. Aprogressive increase in PLW of banana fruit was observed with an increase in ripening period. The overall preferential score (23.93)with aroma (8.01) and taste (7.88) were highest in fruits ripened with tomato (T2) than the rest of the ripening methods.Chemically treated Banana showed highest score for colour 8.89. In case of ripening of fruits calcium carbide, colour change in peel was faster with bright yellow colour but with short shelf life and inferior taste. The use of calcium carbide is known to be carcinogenic as reported earlier; thus an alternative method to induce ripening of fruits with ripe tomato or ripening of banana in covered pits with smoke might be used for ripening of bananas with desirable quality in terms of colour, days require for ripening, biochemical characters and shelf life. Naturally ripened fruit develop poor colour, which might reduce the market price but they had longest shelf life.
Open Access
MORPHO-BIOCHEMICAL CHARACTERIZATION OF JACKFRUIT (Artocarpus heterophyllus Lam.) TYPES OF ASSAM
(AAU, Jorhat, 2019-02) Dey, Biswajit; Baruah, Kartik
Jackfruit (Artocarpus heterophyllus Lam) is an underutilized fruit of Assam. It is mostly grown as backyard crop in homestead garden. The fruit is a good source of energy, vitamins, minerals, flavonoids, etc. Jackfruit is indigenous to the rain forests of the Western Ghats of India. Most jackfruit plants are of seedling origin in the region and thus tend to exhibit a wide range of variability in terms of morphological and biochemical parameters. Therefore, an investigation was undertaken during 2016-2018 on ‘Morpho-biochemical characterization of jackfruits (Artocarpus heterophyllus Lam) of Assam to study the existing variability. One district in each of the six agro climatic zones was chosen and four plants were selected in each district, comprising of twenty four plants. Wide variability was observed among the selected jackfruit accessions for morphological characters. Variability in crown shapes like irregular, elliptical, oblong and spherical were observed. Wide variations in leaf blade shape i.e. elliptic, obovate, oblong, broadly elliptic and narrowly elliptic were recorded in the selected jackfruits. Different fruit shapes like ellipsoid, spheroid, oblong, clavate, oblong and irregular were recorded in the selected accessions. Flake texture and flake flesh colour also showed wide variation. In seeds, different seed shapes such as ellipsoid, irregular, reniform, spheroid and oblong were recorded. Cluster analysis of 23 qualitative characters using Average Linkage Between Groups resulted in grouping of the jackfruit accessions into eight non-overlapping clusters. Cluster I consisted of 6 accessions, Cluster II consisted of 4 accessions, Cluster III consisted of 5 accessions, Cluster IV consisted of 2 accessions, Cluster V consisted of 2 accessions, Cluster VI consisted of 2 accessions, Cluster VII consisted of 2 accessions and Cluster VIII had only 1 accession. The clusters formed did not comprise of accessions based on geographical location indicating that qualitative traits were largely influenced by genetic factors. The quantitative characters of flower, leaf and fruit showed significant variation among the jackfruit accessions. The highest tree height and trunk circumference recorded was 18 m and 198 cm respectively (SON2) and the lowest recorded was in 7 m and 120 cm respectively (CAC3). The number of fruits per tree ranged from 9 to 68 with an average of 26.25. The highest fruit weight among the accessions recorded was 10.89 kg (GLP3) while the highest fruit length was 46.67 cm (SON1). The highest number of flake per kg of fruit recorded was 38.18 (SON4) while the highest weight of flake per kg of fruit recorded was 0.54 kg (SON1). The highest flake seed ratio observed was 7.29 (CAC3) while the highest 100-seed weight recorded was 900g. In terms of biochemical constituents, the highest TSS recorded was 29.70°Brix while the highest TSS: acid ratio recorded was 229.57. The highest total sugar recorded was 26.87% (NAG2) while the highest ascorbic acid content recorded was 14.29 mg/100g (CAC1). The highest crude fibre content recorded was 3.17% and the highest total flavonoid content recorded was 127.45mg QE/100g. The highest antioxidant activity was recorded in accession number CAC1 (80.12%) and the lowest antioxidant activity was recorded in accession number JRT1 (32.46%). The lowest IC50 value was recorded in accession number CAC1 (0.62 mg) indicating high antioxidant potential over all other accessions. The seed biochemical constituents also showed significant variations. The highest seed crude protein content was recorded in accession number SON4 (21.18%), while the highest starch was reported in accession JRT1 (35.30%). The highest total mineral (ash) content was recorded in accession number SON2 (5.18%) and the lowest in accession number KA4 (2.89%). The effect of locations on quantitative characters was found to be non-significant. Fruit length and diameter of jackfruit accessions showed significant positive correlation with fruit weight. A significant positive correlation was also found between fruit weight with number of flakes per kg of fruit and weight of flake per kg of fruit. Among the biochemical parameters, the correlation between ascorbic acid and total antioxidant activity was found to be highly significant.
Open Access
Evaluation of moisture stress response of Cynodon dactylon (L.) and its recuperative ability by using plant growth regulators
(AAU, Jorhat, 2019-05) Gogoi, Prarthana; Mahanta, Pradip
An experiment was conducted to study the “Evaluation of moisture stress response of Cynodon dactylon (L.) and its recuperative ability by using plant growth regulators” with three different plant growth regulators like Trinexapac-ethyl (TE), Paclobutrazol (PBZ) and Flurprimidol (FD) under nine different concentration levels in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat during 2015-2018. The experiment was laid out in factorial Randomized Block Design. The ten treatments comprised of T0 - Control, T1 -100 ppm TE, T2- 200 ppm TE, T3-300 ppm TE, T4 – 500 ppm PBZ, T5 – 1000 ppm PBZ, T6 – 1500 ppm PBZ, T7 – 50 ppm FD, F8 – 100 ppm FD and T9- 150 ppm FD. These treatments were applied in two methods, viz., during the moisture stress (Method I) and before stress (Method II). Experimental results revealed that visual characters, plant growth, physiological characters and biochemical parameters were significantly influenced by treatment, method and their interaction effect. Regarding the treatment effect Treatment T1 exhibited the highest mean performance for turf quality at before stress, turf quality at 15th day stress, turf quality at 15th day after rewatering, turf color at before stress, turf color at 15th day stress and turf color at 15th day after rewatering , coverage percentage at before stress, coverage percentage at 15th day stress and coverage percentage at 15th day after rewatering, clipping fresh weight at 15th stress and clipping fresh weight at 15th day after rewatering, clipping dry weight at 15th day stress and clipping dry weight at 15th day after rewatering, relative leaf water content at before stress, relative leaf water content at 15th day stress and relative leaf water content at 15th day after rewatering, shoot N content at before stress, shoot N content at 15th day stress and shoot N content at 15th day after rewatering, shoot P content at before stress, shoot P content at 15th day stress and shoot P content at 15th day after rewatering, shoot K content at before stress, shoot K content at 15th day stress and shoot K content at 15th day after rewatering, stolon length at before stress, stolon length at 15th day stress, stolon length at 15th day after rewatering and turf density at before stress, turf density at 15th day stress and turf density at 15th day after rewatering. Treatment T3 exihibited the highest mean performance for root fresh weight at before stress, chlorophyll content at before stress, chlorophyll content at 15th day stress and chlorophyll content at 15th day after rewatering and chlorophyll stability index at before stress, chlorophyll stability index at 15th day stress, chlorophyll stability index at 15th day after rewatering and the lowest mowing frequency. Treatment T6 exhibited the highest mean performance for root fresh weight at 15th day stress and root fresh weight at 15th day after rewatering, leaf proline content at before stress, leaf proline content at 15th day stress and leaf proline content at 15th day after rewatering and SOD enzyme activity at before stress, SOD enzyme activity at 15th day stress and SOD enzyme activity at 15th day after rewatering and Treatment To exhibited the highest mean values for clipping fresh weight and clipping dry weight at before stress condition and mowing frequency. It was observed that the treatments applied in method II exhibited the highest mean performance for all the visual, growth, physiological and biochemical characters. From the experiment it was clearly observed that most of the growth characters, physiological characters as well as biochemical characters were influenced by treatments, methods which may be due to positive effect of Plant Growth Regulator during the growth period. The Plant Growth Regulator Trinexapac-ethyl was the most effective PGR to maintain the turf quality and reducing the mowing frequency. The best treatment was found to be T1 and Method II and their interaction was considered the best for growth characters as well as quality characters, viz. colour, resiliency, rigidity and uniformity etc.
Open Access
QUALITY OF SWEET POTATO FLOUR AS AFFECTED BY BY PRE–TREATMENT AND DRYING METHODS
(AAU, Jorhat, 2019-07) Borah, Mriganka Shekhar; Samindra Baishya
Sweet potato (Ipomoea batatas, family:Convolvulaceae) is a perennial crop, grown in tropical and subtropical lowland agro-ecologies, although it is well adapted to other zones and can be grown in different environmental conditions. Sweet potato is an excellentsource of energy, but due tolow digestibility of the starch it is suitable fordiabetic or overweighed people. Because of its highly perishable nature, there are many problems related to storage and transport of the raw sweet potatoes. However, it can be processed into flour, which is less bulky and more stable than the highly perishable fresh root.The present investigation was aimed to evaluate the effect of pre-treatment and drying methods on chemical composition and the functional properties of sweet potato flour. Fourpre-treatment methods (soaking in water, T1;blanching, T2; calcium chloride solution, T3 and pre-drying at 100oC for 5minutes, T4along with thecontrol, T5) and three drying methods (sun drying,D1 oven drying,D2 and microwave drying,D3) were employed in the preparation of flour from three varieties of sweet potato (Dergaon red, Shree Bhadra and ST-14).Drying methods and pre-treatment were found to influence all the parameters studied, titratable acidity remained unaffected by the drying methods.The pre-treatments caused significant reduction in the nutritional parameters compared to control with T4 being the worst. Sun drying was found better in maximum retention of crude protein, crude fat, starch and amylose over the other two. Microwave drying was found better for crude fibre and ash content. Functional properties of sweet potato flour were also affected by the pre-treatment and the drying methods with T4 and D3 affecting the most of them. The interactive effect of variety, pre-treatment and drying method was found to have a significant effect in all the attributes of sweet potato flour. Orange fleshed variety, ST-14 was found nutritionally superior over the other two and the quality and functional properties of flour was best with treatment combinations, T5D1. Sun drying of sweet potato slices with no pre-treatment was found better in preparing sweet potato flour over any other combinations used in the study.

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