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Investigating the effect of post-harvest treatment on nutritional and antioxidant activities of Ulva lactuca originating from Bangladesh
Journal of Applied Phycology (Springer Nature, 2026) · DOI: 10.1007/s10811-026-03846-4Abstract: To utilise seaweed commercially, post-harvest processing is typically essential, serving to prevent decay, extend shelf life, and facilitate the extraction of specific chemical components. In this study, the presence of a variety of nutritionally important compounds in Ulva lactuca was investigated following different treatments: washing with fresh water (fresh), followed by drying under freeze dryer, open air, direct sun and conventional oven. The analysis encompassed the determination of proximate composition (carbohydrates, proteins, lipids, ash, and moisture), elements (C, H, N, S and P) and metal contents, bioactive compounds (phenolics and flavonoids), and in vitro antioxidant activities. The findings indicate that U. lactuca is rich in essential minerals, and total carbohydrate content is not significantly influenced by post-harvest drying treatments. Sun-dried U. lactuca exhibited the highest lipid (5.71 ± 0.41 % DW), phenolic content (52.9 ± 0.33 mg GAE g-1 DW), and total antioxidant capacity (16.19 ± 1.09 mg AAE g-1 DW), while air-dried only preserved the highest FRAP activity (0.38 ± 0.04 mg Fe2⁺E g-1 DW) and DPPH scavenging (0.25 ± 0.03 mg AAE g-1 DW). Freeze-dried samples retained the highest protein content (9.69 ± 0.27 % DW) and reducing power (1.59 ± 0.05 mg AAE g-1 DW), whereas total flavonoids were greatest in the fresh sample (9.58 ± 0.08 mg QCE g-1 DW). Overall, sun or air drying are indicated as effective, low-cost methods for preserving the nutritional and bioactive qualities of U. lactuca compared to freeze or oven drying. -
Comparison of phenolic content and antioxidant activity of two common fruits of Bangladesh in solvents of varying polarities
Journal of Food Research (2021) · Peer-ReviewedAbstract:Phenolic content and antioxidant activity of two common fruits of Bangladesh, namelyPhyllunthus emblica and Elaeocarpus floribundus, were measured in water, methanol,ethanol, acetone and hexane extracts. Several in vitro models includingphosphomolybdenum assay, DPPH free radical scavenging assay, FRAP assay andreducing power assay were used to assess the antioxidant activity of these extracts incomparison with reference antioxidants. Between the two fruits, P. emblica showed higherphenolic content and antioxidant activity in all the solvents used. In the DPPH scavengingassay, the activity of P. emblica extracts was close to reference antioxidants, ascorbic acidand BHT. Besides, considering the solvents used, extracts of both fruits had the highestphenolic and antioxidant activity in polar solvents. The correlation coefficient betweentotal phenolics and antioxidant activities was found statistically significant. These findingssuggest that P. emblica could be an excellent antioxidant resource for industries like food,pharmaceutical, and cosmetics. -
Presence of cellulolytic and xylanolytic activities in the gut fluid of grasshopper Oxya velox
Journal of BioTechnologia (2019) · DOI: 10.5114/bta.2019.89745Abstract: Insect guts, particularly of phytophagous insects, are considered as intriguing bioprospecting sources of cellulase and xylanase due to their use in biofuel industry. In this study, the activities of cellulase and xylanase were identified in the gut fluid of grasshopper, Oxya velox, and characterized. Qualitative assays of gut fluid carried out for endo-β-1,4-D-glucanase (EC 3.2.1.4) and endo-β-1,4-D-xylanase (EC 3.2.1.8) activities, using substrate-agar plate method, revealed clear transparent zones against the red-stained background. When measured by dinitrosalicylic acid method, the gut fluid had 0.759 ± 0.005 U and 0.303 ± 0.002 U of endoglucanase and endoxylanase activities, respectively, per mg of protein. In the gel zymogram, four distinct cellulolytic protein bands and one xylanolytic protein band were detected against substrates carboxymethyl cellulose and xylan, respectively. The optimal temperature and pH of both endo-β-1,4-D-glucanase and endo-β-1,4-D-xylanase were 55°C and 5, respectively. Preincubation at 70°C for 20 min resulted in almost complete loss of endo-β-1,4-D-glucanase activity as shown by zymography. The presence of both cellulase and xylanase activities suggested that O. velox could be considered as a model for studying the process of lignocellulose digestion in insect gut; the insect could also serve as a good source of enzymes for biofuel production. -
Effect of extraction solvents on phenolic contents and antioxidant capacities of Artocarpus chaplasha and Carissa carandas fruits from Bangladesh
Journal of Applied Biology & Biotechnology (2017) · Open AccessAbstract: Increased intake of fruits, due to their high antioxidant capacity, is known to reduce the risk of many diseases. The high antioxidant capacity of fruits is attributed to the presence of phenolics. The aim of the present study was to evaluate how solvents affect the extraction of phenolic and flavonoid substances and the antioxidant activity of fruit extracts of A. chaplasha and C. carandas. The fruits were extracted using water and various concentrations (50%, 70% and pure) of methanol, ethanol and acetone in water as solvent. Phenolic and flavonoid contents were measured by Folin-Ciocalteu method and aluminum trichloride method respectively. Antioxidant activity was measured by DPPH free radical scavenging assay. The efficiency of solvents in extracting phenols varied considerably for both fruits. Phenolic content and antioxidant activity was highest in 70% acetone extract and lowest in 100% acetone extract whilst flavonoid content was highest in pure ethanol extracts of both fruits. Strong correlation was found between the phenolic contents and antioxidant activities. Between the two fruits, C. carandas had higher phenolic content and antioxidant activity in all solvents, suggesting the fruit could be a potential source of natural antioxidant for food and nutraceutical applications. -
Phytochemical screening, phenolic content and antioxidant activity of wild date palm (Phoenix sylvestris Roxb.) fruit extracted with different solvents
International Food Research Journal (2017) · Indexed ScopusAbstract: Fruits are known to have different levels of antioxidant capacity due to the presence of multiple types of phenolic compounds in varying amounts. In this study, phytochemical constituents, phenolic content, flavonoid content, and antioxidant activity of Phoenix sylvestris fruit were investigated. Three solvents (methanol, ethanol, and acetone) with different concentrations (50%, 70% and 100%) and water were used for extraction. Phytochemical analyses showed the presence of tannins, flavonoids, and saponins. Fruits extracted with 70% acetone showed highest total phenolic content (1554.85 mg GAE/100 g FW) and total flavonoid content (2121.77 mg CEQ/100 g FW) whereas lowest total phenolic content (212.94 mg GAE/100 g FW) and lowest total flavonoid content (130.41 mg CEQ/100 g FW) were found in H2O extract. Antioxidant activities of different solvent extracts were evaluated using ferric reducing antioxidant power (FRAP) assay, total antioxidant capacity assay, reducing power assay, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assays. With all the assay methods, 70% acetone extract showed the highest antioxidant capacity. It was also observed that the phenolic contents were strongly correlated with the antioxidant activity. -
Total phenolic content, reducing power, antioxidative and anti-amylase activities of five Bangladeshi fruits
International Food Research Journal (2014) · Indexed ScopusAbstract: Phenolic content, antioxidant and anti-amylase activities were studied in the ethanolic extract of five available Bangladeshi fruits. The fruits were Averrhoa bilimbi (Bilimbi), Artocarpus lacucha (Monkey jack), Cucumis melo (Muskmelon), Phoenix sylvestris (Wild date palm), and Flacourtia jangomas (Indian plum). P. sylvestris had the highest total phenolic content (37.40 ± 1.72 mg GAE/10 g of extract), whereas C. melo had the lowest (6.02 ± 0.89 mg GAE/10 g of extract). All the fruits showed DPPH free radical scavenging activity with IC50 values for P. sylvestris, A. lacucha, F. jangomas, C. melo, and A. bilimbi at 1.90 μg/ml, 0.798 mg/ml, 1.144 mg/ml, 1.695 mg/ml, and 3.683 mg/ml respectively. Highest level of reducing activity was found in P. sylvestris (O.D. 0.933 ± 0.02) and reducing power activity was lowest in A. bilimbi (O.D. 0.249 ± 0.01) at a concentration of 0.4 mg/ml, with all fruits showing a dose-dependent increase in reducing power. The fruit extracts showed mild inhibition of α-amylase activity, with the highest activity found in P. sylvestris (11.88 ± 3.69%) and the lowest for F. jangomas (3.33 ± 0.64%). Considering the data, it can be concluded that among the five fruits, P. sylvestris is the most health beneficiary. -
Isolation and identification of cellulolytic bacteria from the gut of three phytophagus insect species
Brazilian Archives of Biology and Technology (2014) · DOI: 10.1590/S1516-89132014005000018Abstract: The cellulolytic bacteria from the gut of three different phytophagous insects were studied to isolate novel cellulolytic organisms for the biofuel industry. Among the three, the gut of P. quatuordecimpunctata larvae contained both the highest total bacterial count (6.8 × 107 CFU/gut) and cellulolytic bacteria count (5.42 × 103 CFU/gut). Fifteen different isolates were obtained from the gut of O. velox, A. miliaris, and P. quatuordecimpunctata. All the isolates produced clear zones in CMC medium when stained with Congo red. The isolates included Gram-positive Enterococcus, Microbacterium and Gram-negative Aeromonas, Erwinia, Serratia, Flavobacterium, Acinetobacter, Klebsiella, Yersinia, Xenorhabdus, Pseudomonas, and Photorhabdus. Out of the fifteen isolated and identified bacterial species, twelve bacterial species were novel, being reported for the first time as having cellulase activity. -
Racial variations in serum lipid and lipoprotein levels in Bangalee and Chakma populations of Bangladesh
International Journal of Current Research and Review (2013) · Clinical BiochemistryAbstract: Background: Racial differences in serum lipid and lipoprotein levels exist and are assumed to be important determinants of cardiovascular disease. The purpose of this study was to investigate whether differences in serum lipid and lipoprotein levels exist between two distinct populations in Bangladesh. Materials and Methods: Ninety-one Chakma subjects (43 male and 48 female) and an equal number of Bangalee subjects (39 male and 52 female) were randomly selected. Serum Total Cholesterol (TC), Triglycerides (TG), and High-Density Lipoprotein Cholesterol (HDL-C) were measured using commercial enzymatic kits, and Low-Density Lipoprotein Cholesterol (LDL-C) was calculated. Results: Bangalee subjects exhibited significantly higher levels of TC, TG, and LDL-C, and lower levels of HDL-C compared to the Chakma population. Bangalee males had higher TC, TG, and LDL-C than Chakma males, with no significant difference observed for HDL-C. Bangalee females had higher TC and TG and lower HDL-C than Chakma females, with no significant difference found for LDL-C. Conclusion: This study clearly demonstrated that racial variations exist in serum lipid and lipoprotein profiles between the Bangalee and Chakma populations of Bangladesh. -
Comparative analysis on the major nutrient composition of locally available four different varieties of rice (Oryza sativa) in Bangladesh
Research Journal of Science and Technology (2012) · Food CompositionAbstract: The aim of the present study was to obtain comparative data on chemical compositions and nutritive values of four different varieties of rice. The results indicated that moisture, ash, total soluble solids, and crude fiber contents of the different varieties of rice were in the ranges of 9.98–10.90%, 9.45–11.12%, 10.06–11.25%, and 9.35–10.35% respectively. The ranges in the values of total protein, water soluble protein, dry matter, polysaccharide, total sugar, reducing and non-reducing sugar compositions of rice were 12.45–14.06%, 3.20–4.71%, 89.10–90.02%, 10.95–12.25%, 4.35–4.96%, 1.15–1.45%, and 3.10–3.58% respectively. Vitamin B1 and Vitamin B2 contents of rice were found to range from 2.98–3.81 and 0.61–0.86 mg/100 g of rice respectively. Twelve amino acids were detected in all four varieties of rice in the total form by paper chromatography. Rice contained about 14.95–16.16% oil. Triglyceride, diglyceride, monoglyceride, and non-glyceride were found to vary from 91.76–93.08%, 1.51–2.30%, 1.45–1.96%, and 3.63–5.24% respectively. Rice oils contained mostly unsaturated fatty acids which varied from 71.06–74.95%. Total lipids were fractionated into lipid classes by silicic acid column chromatography. -
Multiple Endo-β-1,4-glucanases Present in the Gut Fluid of a Defoliating Beetle, Podontia quatuordecimpunctata (Coleoptera: Chrysomelidae)
Pakistan Journal of Biological Sciences (2012) · EnzymologyAbstract: Endo-β-1,4-glucanase (EC 3.2.1.4) activity was measured in the gut fluid of the phytophagous insect Podontia quatuordecimpunctata Linnaeus (Coleoptera: Chrysomelidae) at different days of development. The eight-day-old larva showed maximum activity with 1.73 U mg−1 of protein, which was confirmed by gel zymography. In zymograms, using Carboxymethyl Cellulose (CMC) as substrate, four distinct cellulolytic protein bands were detected in leaf borer gut fluids throughout its development. The optimum temperature and pH were 60°C and 5.0, respectively. This endo-β-1,4-glucanase showed maximum stability at 20–45°C with approximately 20% remaining activity. Zymography also showed complete loss of endo-β-1,4-glucanase activity at 55°C. This is the first report that the cellulolytic enzyme is produced in the gut of P. quatuordecimpunctata throughout all developmental stages, from the 1st instar to the adult, except for pupae. -
Antimicrobial and cytotoxic activities of larval extract of Musca domestica (house fly)
International Journal of Current Research and Review (2012) · Bioactivity ScreeningAbstract: The principal objective of this study was to investigate the presence of antimicrobial activities in the larvae of the insect Musca domestica (housefly). For this purpose, the body walls of the insect larvae were injured by a sterile hypodermic needle and larval extracts were prepared in acidic (pH 5.0), neutral (pH 7.0), and alkaline (pH 8.0) buffers or water. These extracts were used for screening antimicrobial activities against 11 bacterial and 10 fungal strains by agar disc diffusion assay and poisoned food technique respectively. All three extracts showed inhibition against 2 bacterial species (Salmonella typhi and Bacillus subtilis) and 5 fungal species (Macrophomina phaseolina, Fusarium equiseti, Colletotrichum corchori, Alternaria alternata, and Rhizopus sp.). The acidic extract also showed inhibition against Escherichia coli. Of the three extracts, the acidic extract exhibited the highest inhibition against all tested microbes. Cytotoxic activity (LC50) of the acidic, neutral, and alkaline extracts was determined to be 141.2 μg/ml, 152.2 μg/ml, and 149.5 μg/ml respectively. -
Chemical and microbiological quality assessment of raw and processed liquid market milks of Bangladesh
Continental Journal of Food Science and Technology (2011) · Food SafetyAbstract: Twelve different liquid market milks of Bangladesh were examined to evaluate their chemical and sanitary quality. Six of these were open raw milk bought from local daily markets and the other six were processed packet milk (both pasteurized and UHT [Ultra High Temperature]-processed) available in shops. The twelve samples were examined for the determination of percentage of water, total soluble solids (TSS), fat, solids-not-fat (SNF), lactose, protein, and ash; measurement of titratable acidity; detection of adulterants; enumeration of total bacterial count, staphylococcal, coliform, fecal coliform, Salmonella and Shigella, Aeromonas hydrophila, and psychrophilic counts. Results revealed that most of the raw and pasteurized milks were substandard in both chemical and sanitary quality whereas the quality of UHT-treated milks was excellent. Majority of the raw and pasteurized milks contained fair amounts of lactose, protein, and ash, but a number of these had lesser amount of fat. All the raw and pasteurized milks were found to be contaminated with bacterial loads exceeding the acceptable limit. The indicator organisms (i.e. coliforms and fecal coliforms) were present in most of these samples in large numbers. Pathogenic bacterial genera (Aeromonas, Salmonella, and Staphylococcus) were also identified in some of these. High counts of psychrophilic bacteria were also found in raw and pasteurized milk. In contrast, none of the UHT-processed milks contained any bacteria. Water had been added to five raw and one pasteurized milk, whereas sucrose was detected in five of the six heat-treated samples.
Scholarly Profiles
Principal Investigator Profiles & Citations
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Prof. Dr. Dwaipayan Sikdar
Principal InvestigatorSpecializing in phytochemical isolation, antioxidant biochemistry, proximate nutrition, and plant secondary metabolite characterization.
Prof. Dr. Suman Mojumder
Principal InvestigatorFocusing on C. elegans in-vivo longevity and oxidative stress assays, CADD, and insect gut metagenomics.