Monthly Archives: January 2019
Ashaduzzaman Sagar, Jannat E Tajkia, Md. Eakramul Haque, Md. Solaiman Ali Fakir, A.K.M Zakir Hossain
>>doi: 10.5455/faa.18483 >>PP: 735-743
Soil salinity is an increasing problem in the world and main obstacle to agricultural productivity especially in areas where irrigation is necessary. Adoption of salt tolerant genotype is more important here and so screening of salt tolerant genotypes by quick method, particularly in early stages of their growth is essential. Some laboratory studies using nine sorghum genotypes were conducted to screen salt tolerant genotypes during germination and seedling growth stages. The genotypes were Hybrid sorgo, Debgiri, BD 703, BD 706, BD 707, BD 713, BD 720, BD 725 and BD 738 and salinity levels were 0 dS m−1 (control), 6 dS m−1, 12 dS m−1 and 18 dS m−1. There were 36 (9× 4) treatments in a completely randomized design (CRD) with three replications. Saline treatments were imposed by sea water. To screen out the salt-tolerant genotypes-germination percentage, rate of germination, vigor index and different physiological parameters i.e. germination stress tolerance index (GSTI), root length stress tolerance index (RLSI), shoot length stress tolerance index (SLSI) and fresh weight stress tolerance index (FSTI) were studied. In this study, all the parameters were decreased with increasing salinity. Results showed that sorghum genotypes Hybrid sorgo, BD 703 and BD 707 were categorized as tolerant while Debgiri and BD 713 were as sensitive ones. Besides these, sorghum genotypes were not tolerant up to 18dS m−1 though some of them were tolerant at 12 dS m−1. Overall, these tolerant and sensitive genotypes might be used in the further genetic improvement of the same and different crops.
Keywords: Sorghum, cereal, salinity, osmotic stress, sea water, physiological indices
The study was designed to observe the behavior of mechanical and osmotic dehydration of pineapple, retention of vitamin C content during drying and development of jam from fresh and dehydrated pineapple. Osmotic dehydration carried out with pineapples collected from local market of Mymensingh in July 2015 and found that pineapples contained higher moisture content (93.9%,wb) than normal (85-87%,wb) and showed contradictory osmotic behavior due to higher moisture content and hormonal effect. Then the studies were conducted using pineapples of Gaint Kew variety collected from Madhupur without hormone treatment which contained 86.11% moisture, 0.36% ash, 13.89% total solid, 0.54% protein and 17.38 mg 100g−1 vitamin C. The osmotic concentration behavior was investigated using sugar and combined sugar-salt solution for 6 mm thick pineapple slices and immersion time was 6 hr. The extent of water loss, solid gain and normalized solid content were strongly influenced by strength of osmotic solution. It was found that K-value (mass transfer coefficient) increases with increasing concentration and was the highest (0.15 min−1) for 55/5% sugar/salt solution and lowest (0.07 min−1) for 45% sugar solution. Three different temperatures (55, 60 and 65 °C) and thicknesses (4, 6 and 8 mm) were used to investigate the drying behavior of pineapple slices in a mechanical dryer. Activation energy value of 8.14 Kcal g-mole−1 was found for fresh pineapple slices. 55/5% sugar/salt osmosed and dried pineapple gave 5.46 times higher dryer throughput compared to nonosmosed dried pineapple. Degradation of vitamin C content of pineapple at different air-dry bulb temperatures (55, 60 and 65 °C) of 6 mm thickness was investigated and activation energy for degradation of vitamin C was found to be 14.38 Kcal g-mole−1. Osmotic dehydration prior to air drying, gave the lower rate of degradation of vitamin C during drying compared to that dried without osmosis. Developed jams were tested for their acceptability by sensory evaluation using 1-9 point hedonic scale and jam made from osmotically dehydrated (55/5% sugar-salt and then dried at 60°C) secured highest score (8.5) and ranked as ‘like very much’, while the other products were ranked as ‘like moderately’.
Keywords: Dehydration, osmosis, activation energy, vitamin C, jam