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Open Access
EFFECT OF PLANTING GEOMETRY AND NUTRIENT MANAGEMENT ON GROWTH, YIELD AND QUALITY OF YARD LONG BEAN (Vigna unguiculata ssp.sesquipedalis)
(2023) Sharma, Bedanta; Kachari, Manisha
A field experiment was conducted during 2022-2023 at the experimental farm, Department of Horticulture AAU, Jorhat to study the effect of planting geometry and the impact of nutrient management on growth, yield and quality of yard long bean (variety Red Ribbon). The experiment was laid out in factorial randomized block design (FRBD) consisting of two factors viz., spacing and nutrient dose with three replications. The two spacing were S1 (60 cm × 45 cm) and S2 (60 cm × 30 cm) with five nutrient doses of T0 (control), T1 (15:35:20 kg NPK/ha + 4 t FYM/ha), T2 {15:35:20 kg NPK/ha + 2 t vermicompost/ha + biofertilizer (rhizobium + PSB)}, T3 (25:50:30 kg NPK/ha + 4 t FYM/ha) and T4 {25:50:30 kg NPK/ha + 2 t vermicompost/ha + biofertilizer (rhizobium + PSB)}. The treatments brought significant influences on the various parameters except a few. The growth parameters like number of branches (21.76), number of leaves/plant (87.00), number of pickings (9.73) days to initiation of 50 % flowering (35.49) and days to first picking (43.89) performed their best in the spacing S1 whereas the maximum vine length (198.39 cm) was observed in S2. The maximum values for yield attributing parameters like length of pod (39.60 cm), girth of pod (2.13 cm), weight of green pod (10.60 g), number of pods per plant (42.42), pod yield per plant (0.35 kg) and for quality and biochemical parameters like carbohydrate (7.99 %), protein (2.97 g/100g), fibre content (3.04 %) and anthocyanin content (26.53 mg/100g) were observed in the spacing S1 whereas the maximum pod yield per plot (3.66 kg) and pod yield per hectare (169.48 q) were observed in S2. In case of nutrient dose, the maximum vine length (223.00 cm), number of branches (24.00), number of leaves per plant (106.00), number of pickings (10.50), length of pod (43.17 cm), girth of pod (2.23 cm), weight of green pod (11.00 g), number of pods per plant (47.88), pod yield per plant (0.44 kg), pod yield per plot (4.33 kg) and pod yield per hectare (200.62 q) were observed in the nutrient dose T4 with T3 being at par in many of the parameters. The maximum carbohydrate content (8.11 %), protein content (3.11 g/100g) and anthocyanin content (29.31 mg/100g) were observed in nutrient dose T4 while the maximum ascorbic acid content (9.98 mg/100g), fibre content (3.43 %) and ash content (0.66 %) were observed in T3. The maximum values for soil parameters like organic carbon (0.64 %), available N (253.2 kg/ha), available P (39.7 kg/ha) and available K (141.0 kg/ha) were observed in T4 whereas the maximum soil pH (5.23) was observed in T0. The interaction of both the factors also brought significant influences on the parameters with the parameters like number of branches (25.00), number of leaves per plant (107.67), number of nodes (73.67), number of pickings (10.67), length of pod (45.33 cm), girth of pod (2.37 cm), pod yield per plant (0.46 kg), carbohydrate content (8.23 %) and protein content (3.23 g/100g) performing the best in the treatment interaction T4S1 while vine length (228.00 cm), pod yield per plot (4.96 kg) and pod yield per hectare (229.63 q) recorded their maximum values in T4S2. Computation of economics of production revealed that the maximum gross return (Rs. 918518.52) and net return (Rs. 704693.52) were also observed in T4S2 but the highest B:C ratio (3.53) was observed in T3S2.
Open Access
Crop Regulation in lemon var. Assam lemon (Citrus limon L. Burm.) by pruning
(2023) Goswami, Anwesha; Hazarika, D. N.
The present investigation entitled "Crop regulation in lemon var. Assam lemon (Citrus limon L Burm)” by pruning" was conducted during 2022-2023 at the ICR farm for field experimentation and in the laboratory for qualitative analysis of fruits in the Department of Horticulture, Biswanath College of Agriculture, AAU, Biswanath Chariali with three objectives: (a) to study the effect of pruning on growth, yield and quality of Assam lemon, (b) to study the effect of time of pruning on growth, yield and quality of Assam lemon and (c) to make the fruits available during the lean period particularly during November to February. The experiment was laid out in RBD with 3 replications and 12 treatments. Each treatment consisted of two plants and accordingly 72 plants were selected for conducting the experiment. Pruning considered as treatments were carried out from 1st May, 2022 to 15th October, 2022 at 15 days interval. The results revealed that both the pruning and time of pruning significantly influenced the vegetative growth and production of Assam lemon fruits. Among the treatments, the highest increase in plant height (18.82%) and number of laterals (4.62) per primary shoot was observed in T1 (pruned on 1stMay). Leaf production per terminal shoot was highest (19.33) in T2 (pruned on 15 May) closely followed by T1 (19.22). Shortest duration (18.66 days) for new shoots emergence after pruning was recorded in T6 (pruned on 15th July) while longest period (26.50 days) was observed in plants pruned on 15th October (T12) but the plants under this treatment produced first flower buds within shortest period (43.83 days) from the date of pruning. Days required to attain maturity of fruits from flower bud emergence was lowest (141.5 days) in plants pruned on 1st May (T1). Average number of hermaphrodite flowers (96.09) male flowers (96.70) and total number of ((192.79) were highest in T12 (pruned on 15th October) and plants under this treatment also recorded the highest fruit set (58.44%), fruit retention (92.01%), average number of fruits per plant per month (51.55) and number of fruits per plant per year (360.85). These values were found to be the lowest in plants pruned in May (T1 and T2). Plants pruned on 1st May (T1) recorded the highest values of fruit weight (168.33g), volume of fruit (184.83cc) and fruit length (9.21cm) while thinnest peel (2.95mm) and the highest pulp-peel ratio were recorded in T12 (pruned on 15th October). Among the treatments, T12 (pruned on 15th October) was found to be efficient in terms of quality like highest juice content (35.66 %), TSS (6.330Brix) and ascorbic acid (37.95 mg/100ml) contents. From the present investigation, it was evident that mature fruits could be harvested from November onwards from the plants pruned during May-June. Though total production was lower in these plants as compared to the plants pruned during October (recommended practice) but because of higher prices per fruit during lean period (Nov-Feb), the benefit: cost ratio was also higher than the plants pruned during October from which fruits were harvested from April onwards.
Open Access
GROWTH PERFORMANCE OF LOW CHILLING VARIETIES OF APPLE (Malus pumila) UNDER DIFFERENT NUTRIENT LEVELS IN ASSAM
(2023) Sharma, Antara; Kotoky, Utpal
A field investigation was carried out during the period 2022-23 to assess the effect of varieties and nutrient level on growth characters, physiological parameters, leaf and soil nutrient status of apple (Malus pumila) in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat. The experiment was laid out in Factorial Randomized Block Design with four replications considering three low-chilling apple varieties viz. V1 (HRMN-99), V2 (Dorsett Golden) and V3 (Anna) and five different nutrient levels viz. N1 [FYM 5 kg/plant (Control)], N2 (5 kg FYM+ 50 g urea+ 70g SSP+ 40 g MOP/plant), N3 (5 kg FYM+ 100 g urea+ 140g SSP+ 80 g MOP/plant), N4 (5 kg FYM+ 150 g urea+ 210g SSP+ 120 g MOP/plant) and N5 (5 kg FYM+ 200 g urea+ 280g SSP+ 160 g MOP/plant). The findings of the experiment revealed that the variety V1 exhibited the highest significant plant height (52.67 cm, 101.05 cm, 124.43 cm and 179.76 cm), stem girth (3.91 cm, 5.08 cm, 6.35 cm and 9.91 cm), leaf area (35.33 cm2, 50.24 cm2, 56.18 cm2 and 63.34 cm2) and leaf area index (1.33, 2.04, 2.20 and 2.42) at 90, 180, 270 and 360 DAP respectively. However, the highest number of branches (6.05, 8.75, 10.20 and 14.65) were observed in V2 which was statistically at par with the variety V1. Amongst various nutrient levels, N4 showed the superior performance in terms of plant height (56.78 cm, 115.26 cm, 143.75 cm and 192.03 cm), stem girth (4.51 cm, 6.04 cm, 7.33 cm and 11.30 cm), number of branches (7.00, 10.25, 11.83 and 17.25), leaf area (42.66 cm2, 56.53 cm2, 63.27 cm2 and 69.38 cm2) and leaf area index (1.53, 2.28, 2.44 and 2.61) at 90, 180, 270 and 360 DAP respectively. Among the physiological parameters, the leaf relative water content (63.46% and 71.90%) in variety V1 and (68.81% and 81.77%) under nutrient level N4 were observed to be significantly highest both at 30 and 45 DAT respectively. The total leaf chlorophyll content showed similar trends with the highest (1.58 mg/g fresh wt. and 1.68 mg/g fresh wt. of leaf sample) in variety V1 and (1.72 mg/g fresh wt. and 1.81 mg/g fresh wt. of leaf sample) under nutrient level N4 at 30 and 45 DAT respectively. The leaf nutrient status with respect to leaf N (2.39% and 2.27%), leaf P (0.25% and 0.22%), leaf K (1.75% and 1.71%), leaf Ca (1.45% and 1.65%) and leaf Mg (0.32% and 0.39%) were found to be highest in the variety V1 at 30 and 45 DAT respectively. The nutrient level N4 exhibited the highest significant leaf N (2.66% and 2.50%), leaf P (0.29% and 0.25%) and leaf K (1.84% and 1.83%) at 30 and 45 DAT respectively. However, the nutrient level N3 was found to be superior in terms of leaf Ca and Mg concentrations which was statistically par with N4 at both the studied intervals after application of respective treatments. Analysis of the soil nutrient status after the experiment resulted in significantly highest organic carbon content, available N, P205 and K20 in variety V3 and nutrient level N5 while the highest exchangeable Ca and Mg were observed under the influence of variety V1 and nutrient level N4. Interaction of varieties and nutrient levels also recorded significant effect for most of the growth parameters with the highest obtained under the combination of variety V1 and nutrient level N4. Therefore, based on the results of the present investigation, the low-chilling variety HRMN-99 at nutrient level of 5 kg FYM+ 150 g urea+ 210g SSP+ 120 g MOP/plant can be recommended for apple cultivation under Assam condition in the first year of its plantation.
Open Access
ORGANIC NUTRIENT MANAGEMENT IN OKRA (Abelmoschus esculentus (L.) Moench.)
(2023) Baro, Ankita; Gautam, B.P.
An experiment entitled “Organic nutrient management in Okra (Abelmoschus esculentus (L.) Moench.) was carried out at the Instructional cum Research Farm, Department of Horticulture, Biswanath College of Agriculture, AAU, Biswanath Chariali during 2022-2023 with the following objectives (i) To study the effect of various organic nutrients on growth, yield and quality of Okra, (ii) To sort out the suitable organic nutrient combination for Okra. The experiment was laid out in Randomized block design with 3 replications incorporating 16 treatments viz., T1: FYM @20 t/ha, T2: Vermicompost @5 t/ha, T3: Neem cake @2 t/ha, T4: Poultry Manure @5 t/ha, T5: FYM @10 t/ha + Vermicompost @2.5 t/ha, T6: FYM @10 t/ha + Neem cake @ 1 t/ha, T7: FYM @10 t/ha + Poultry manure @2.5 t/ha, T8: Vermicompost @2.5 t/ha + Neem cake @ 1 t/ha, T9: Vermicompost @2.5 t/ha + Poultry manure @2.5 t/ha, T10: Neem cake @1 t/ha + Poultry manure @2.5 t/ha, T11: FYM @10 t/ha + Biofertilizer Consortia, T12: Vermicompost @2.5 t/ha + Biofertilizer Consortia, T13: Neem cake @1 t/ha + Biofertilizer Consortia, T14: Poultry manure @2.5 t/ha + Biofertilizer Consortia, T15: FYM + Recommended NPK, T16: Untreated Control. In the present study, the inorganic treatment T15 was found to perform best in terms of growth and yield. Significantly the highest plant height (66.02 cm and 94.00 cm at 45 DAS and at 60 DAS, respectively), internodal length (8.73 cm at 60 DAS), length of leaf (17.98 and 20.25 at 45 DAS and 60 DAS respectively), breadth of leaf (20.23 and 22.74 at 45 DAS and 60 DAS respectively) and number of functional leaves per plant (12.71 and 16.52 at 45 DAS and 60 DAS respectively) were recorded in T15. Among organic treatments, the highest plant height (65.70 cm and 90.70 cm at 45 and 60 DAS respectively), internodal length (7.86 cm at 60 DAS), length of leaf (17.84 and 19.54 at 45 DAS and 60 DAS respectively), breadth of leaf (20.04 cm and 22.04 cm at 45 DAS and 60 DAS respectively) and number of functional leaves per plant (12.16 and 16.06 at 45 DAS and 60 DAS respectively) were recorded in treatment T1. All the physiological parameters viz. area of a leaf, leaf area per plant, leaf area index, total leaf chlorophyll content, chlorophyll stability index and relative leaf water content were recorded significantly highest in inorganic treatment (T15). Among the organic treatments these parameters were found best in T1 whereas the lowest was recorded in T16 (Control). The minimum days for appearance of the first flower (30.12 days) and days to first harvest (37.12 days) were recorded in treatment T11 and maximum harvest duration was recorded in T15 (41.43 days). Again, the maximum number of fruits per plant (18.99), fruit length (14.10 cm), fruit girth (6.55 cm), fruit volume (18.42 cc), the weight of individual fruit (15.71 g), fruit yield per plant (0.29 kg) and yield per hectare were recorded in treatment T1. However, the fruit yield per hectare was significantly highest in inorganic treatment T15 (14.12 t/ha). Among all the treatments the highest vitamin A (375.06 I.U) and vitamin C (29.00 mg/100g) were recorded in organic treatment T5 and minimum fiber content was recorded in T12 (9.76 %). Minor incidences of pests and diseases were observed and it was controlled effectively at the initial stage by applying proper organic fungicide and insecticide. Considering the highest B:C ratio (2.53:1) and with superior morphophysiological attributes among the organic treatments in T1, it could be advised to the grower of this region to apply FYM @20t/ha in Okra to get a good crop harvest with quality fruit.
Open Access
DEVELOPMENT OF NANOPARTICLE-BASED FOOD EMULSION TO STABILIZE CURCUMIN IN AQUEOUS FOOD MEDIUM
(2023) Gade, Priyanka; Purkayastha, Manashi Das
Emulsions are thermodynamically unstable bi-phase systems whose basic components include a continuous phase, a dispersed phase, and an emulsifier. Emulsifier is an amphiphilic compound that immediately adsorbs to freshly formed oil droplets and prevents their aggregation. Based on the nature of origin, emulsifiers are classified into natural and synthetic emulsifiers; as the latter is often associated with carcinogenic properties, now researchers are heading towards identifying and exploring natural emulsifiers (without derivatizing or modifying the chemical composition). Among natural compounds/molecules that can act as emulsifiers, proteins are of great interest because of their wide functional properties. Even though these protein molecules can stabilize emulsions in the initial period, in the long term they tend to de-stabilization. Conjugation of proteins to other bioactive molecules like polyphenols can enhance their functionalities, thereby improving the stability of protein-stabilized emulsions. In this study, rapeseed protein-tea polyphenol (P-P) nano-conjugates were created, which were then used at different concentrations (0.25% to 1.5% (w/v)) to fabricate emulsions (namely E1 (0.25%), E2 (0.5%), E3 (0.75%), E4 (1.0%), E5 (1.25%), and E6 (1.5%)) by using curcumin containing oil (5 mg curcumin/ml of oil) and aqueous medium (200 mM phosphate buffer, pH-7.0). The synthesized emulsions were exposed to various storage and thermal processing conditions (4℃, 25℃, 90℃, and 121℃), and subsequently, their physico-chemical characteristics were analyzed. Emulsifying capacity and centrifugal stability were found to increase with an increase in conjugate concentration. Droplet size of emulsions increased throughout the storage period; samples stored at 4℃ (without any thermal pre-treatment) recorded smaller diameter, and sterilized emulsions (stored at 4℃) recorded larger size. Zeta potential showed higher negative values for emulsions stored at 4℃ (without any thermal pre-treatment) and lower values for the sterilized samples (stored at 4℃). Values of zeta potential were seen to increase with the storage period. Creaming was observed in E1 (0.25%) of emulsions stored at 4℃ and E1 (0.25%) & E2 (0.5%) of emulsions stored at 25℃ (without any thermal pre-treatment) from the storage period of 24 h, whereas thermally treated emulsions (stored at 4℃) with low concentrations of conjugates started to show creaming tendency from the storage period of 168 h (7 days). Entrapped curcumin was recorded more in samples stored at 4℃ (without any thermal pre-treatment), and the least was noted in the sterilized emulsions (stored at 4℃). Values of loading efficiency of curcumin and DPPH scavenging activity also followed the same pattern. There is a significant difference (p<0.05) for all tested characteristics of samples throughout the storage period, and among all the emulsions under this study, E6 (bearing 1.5% conjugate) stored at 4℃ (without any thermal pretreatment) was found to perform the best. Further, the performance of P-P conjugates in stabilizing curcumin was compared against six commercially renowned permissible food emulsifiers (adding their maximum concentration as prescribed by FSSAI guidelines). These were as follows: CMC-Carboxyl methyl cellulose (0.5% w/v), DATEM-Di-acetyl-tartaric acid ester of mono-triglycerides (0.2% w/v), GMS-Glycerol Mono-stearate (0.5% w/v), INS-475 - Polyglycerol Polyricinoleate esters (0.5% w/v), LACTEM- Lactic Acid Esters of Mono –Diglycerides (0.2% w/v), and Soy lecithin (1.5% w/v). Except for soy lecithin, all other tested emulsifiers failed to form stable emulsions with curcumin-loaded oil under the given test conditions. Hence, a comparative study was carried out between soy lecithin and P-P conjugate-stabilized emulsions. Following the same concentration as adopted for P-P conjugates, soy lecithin formed emulsion at all given concentrations (e1- 0.25%, e2 - 0.5%, e3- 0.75%, e4 -1%, e5-1.25%, e6 - 1.5%); however, dispersion of curcumin appeared to be non-homogeneous (as evident from a dense yellow emulsified phase at the top). Soy lecithin showed less emulsifying capacity at lower concentrations compared to P-P conjugates, and immediately after thermal treatment, most of the emulsions formed by soy lecithin presented complete separation. Based on visual observations, the dispersibility of curcumin by soy lecithin was poorer than that of the P-P conjugates. After 72 h, there was a complete separation of phases in soy lecithin-based emulsions stored at 25℃. At the end of the stipulated storage period, i.e., 336 h (14 days), the best emulsion amongst the soy lecithin stabilized ones, i.e., e6 (stored at 4℃ without any thermal pretreatment), could entrap only 0.08 mg of curcumin per ml of emulsion, which was half of the curcumin entrapped by that of P-P conjugates (i.e., 0.186 mg/ml), and exhibited nearly 3 times less antioxidant activity (14.2%) than that showed by P-P conjugates (42.1%). So, the overall performance of soy lecithin was low compared to P-P conjugates at the given test conditions to stabilize curcumin in the aqueous phase. And thus, the synthesized nanoconjugates can be recommended for food and pharmaceutical usage, if high dispersibility of curcumin is desired therein.
Open Access
Phytochemical analysis of dried leaves of Paederia foetida
(2023) Saikia, Prapti; Baishya, Samindra
With advancing gain of interest in medicinal herb due to its health benefits, drying of leaves play an important role in packaging and preservation. Being highly perishable, drying of P. foetida leaves can be utilised for its widespread use. The present study was carried out to identify the impact of drying methods on phytochemical content and antioxidant activity of P. foetida leaves. Different drying techniques utilised in the study were oven drying at 40ºC, 50ºC, sun drying, solar drying and shade drying. Preliminary phytochemical screening of ethanolic extract revealed presence of phenol, flavonoid, tannin, glycoside and terpenoid. Impact of drying methods on phytochemical content was found significant. Moisture content of dried sample ranged from 11.18%in oven dried sample @50 ºC to 12.76% in shade dried sample. Total phenolic, flavonoid and tannin contents varied from 10.97- 16.46 mg GAE/g, 2.22- 8.39 mg QE/g, 4.25- 4.90 mg TAE/g respectively with highest amount in solar dried sample. Ascorbic acid content was retained most in oven dried sample @50 ºC with 8.4 mg/100 g and lowest in shade dried sample with of 7.2 mg/100 g. Total antioxidant activity ranged from 10.30-15.69 mg AAE/g with maximum activity in solar dried sample. Scavenging activity using DPPH free radical portrayed a gradual increase in activity with increased concentration of sample extract. Highest inhibition was recorded for solar dried sample. Solar dried sample was found best amongst the drying treatments on retention of bioactive compounds and antioxidant activity.
Open Access
PECTIN-BASED MICROENCAPSULATION OF PROBIOTICS FOR IMPROVING SURVIVAL IN GASTRO-INTESTINAL TRACT
(2023) Gogoi, Pratyasha; Saikia, Ananta
The probiotic organisms exert various health benefits. The viability of probiotics is reduced while passing through the stomach and upper intestine because of the low pH. In this study, pectin was extracted from lemon peels and pumpkin, and microcapsules were made by encapsulation of probiotic microorganism species Lactobacillus plantarum, L. delbrueckii and Pediococcus. pentosaceous with plant-based pectin through emulsification. The degree of esterification was highest in lemon pectin (66.10%) with the highest encapsulated bead yield of 13.08g/g pectin. The initial probiotic cell count of L. plantarum, L. delbrueckii and P. pentosaceous was 9.54, 9.61 and 9.51 log cfu/ml respectively. The microcapsules of L. delbrueckii gave the highest viability attributed to its higher tolerance to acid. The microcapsules of L. plantarum, L. delbrueckii and P. pentosaceous achieved encapsulation yields of 84%, 86% and 83% from lemon pectin and, 81%, 83% and 83% from pumpkin pectin respectively. However, results of simultaneous incubation in simulated gastric and intestinal fluid revealed a slight reduction in the viability of encapsulated cells remaining within 5 log cfu/ml. The microencapsulated beads were observed under the inverted microscope to detect the presence of bacteria after gram staining which showed gram- positive cells. No difference was detected in the bead appearance by environmental scanning electron microscopy, except that the pectin beads made from lemon peel pectin resulted in lesser severe wrinkles on the surface. The overall study indicated that the most stable microcapsules were made from lemon peel pectin with the potential for industrial application.
Open Access
DEVELOPMENT OF BIODEGRADABLE BIOPLASTIC FROM BANANA PEELS
(2023) Talukdar, Nilakshi; Boro, Robin Chandra
The development of biodegradable bioplastic has gained significant attention in recent years due to its potential as a sustainable solution for plastic waste management. The present study was to develop bioplastic from banana peels and characteristic its physical properties. The biofilm was prepared from banana peels by casting method using glycerol (10%) as a plasticizer and corn starch as co-biopolymer. Five banana peel bioplastics (T1 -T5) were prepared with different concentrations of corn starch (2%, 4%, 6%, 8% and 10% respectively) and the bioplastic (T0) without corn starch was taken as a control. Based on the study, the thickness of the bioplastic was recorded in the range of 0.38 mm - 0.59 mm. The bioplastic (T4) with 8% corn starch was found to have the highest tensile strength of 0.388 MPa as compared to other treatments. The highest water solubility was observed in the bioplastic (T5) with 10% corn starch. At different temperatures (250C, 300C and 350C), the water vapour transfer rate (WVTR) of the bioplastic were studied. The best result for WVP was observed in T5 where the concentration (10%) of corn starch was highest. The biodegradability of the films was determined by carbon dioxide evolution. There was a gradual increase in carbon dioxide evolution from day 7th to day 90th. After 90 days the net carbon dioxide evolution was recorded as 0.5190 g for T4 (corn starch 10%). Lastly, the microbial growth was detected only after 60 days of storage. The study revealed that the treatment T4 (Glycerol 10% and 8% corn starch) is found to be the best among the treatments considering its highest tensile strength (0.388 MPa), elongation percent (9.77%), maximum load (2.48 N), intermediate solubility (34.12%), thickness (0.56 mm), susceptibility to microbial contamination and biodegradability. Effects of concentration of corn starch showed positive effect on water vapor transmission rate of the bioplastics. By using bioplastic, the environmental pollution can be reduced as well as the waste banana peels can be turned into a new value-added biodegradable plastic product.
Open Access
MECHANICAL DE-SEEDING OF ROSELLE AND ITS EFFECTS ON QUALITY OF BREWED ROSELLE TEA
(2023) Mudoi, Nani Gopal; Borah, Abhijit
The manual deseeding of Roselle is time-consuming and labour-intensive process. Dealing with bulk quantities manual, deseeding can result in loss of edible parts of calyx due to human error and drudgery. Therefore, considering the need and expectations of the small-scale manufactures of Roselle products, an efficient, low-cost, fast deseeding design was developed and compared with hand/manual deseeding. The developed machine has a foot paddle and link mechanism. Coil spring mechanism has been provided for return action of the punching tool to its original position. The machine cost was estimated to be Rs.1800/-. The rate of deseeding by the machine was 2.5 kg/h with minimum broken percentage producing good quality of deseeded calyces. When compared with manual deseeding, it was found that manual deseeding capacity was 1.5 kg/h apart from quality degradation of the calyces. Brewed Roselle tea was taken for quality tests to see the effect of mechanical deseeding against manual deseeding. Mechanically and manually deseeded whole calyx and powder (dried at 80 °C) were selected as treatments. The quality parameters like Anthocyanin (monomeric), Total phenol content, Total flavonoid, Antioxidant activity, Total soluble solids, Colour, Sensory Analysis, Bulk density, True density, Porosity were determined for both mechanical and manual deseeded calyces and powders. The highest mean of monomeric-anthocyanin content was found in mechanically deseeded powder and whole calyces’ tea (39.83 mg/ml and 16.59 mg/ml), same trend was observed for the phenol content (26.03 mg/ml and 14.58 mg/ml), flavonoid content (24.37 mg/ml and 16.56 mg/ml) and antioxidant activity (88.70% and 87.60%). Sensory assessment of the Roselle tea revealed that mechanically deseeded whole calyx dried at 80 °C was highly accepted and judged best among other Roselle tea samples. Mechanically deseeded calyces dried at 80 °C exhibit higher porosity (51.41%) and lower bulk density (0.69 gm/cm3), which plays important role for production of tea or herbal infusion of dried Roselle because a lower bulk density allows for better infusion and extraction of flavours and compounds. The result obtained from the quality parameters opened up a possibility having a good impact on the small-scale manufactures, marginal farmers and Self-help groups (SHGs) for having a good quality Roselle’s products and smooth deseeding operation with the deseeder.

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