Pectinase is an enzyme having a broad industrial and commercial application. However, higher production costs may be the major constraint for the wide-scale application of pectinase. Therefore, researchers are trying to reduce the pectinase production cost for subsequent application in the industrial processes by using a unique substrate and optimizing the fermentation medium components and process conditions. The main purpose of the current study was to optimize medium composition for pectinase production using Aspergillus niger -ATCC 1640 in the solid-state fermentation. The Response Surface Methodology (RSM) was performed to evaluate the effects of variables, specifically the concentrations of Satkara peel, urea, (NH 4 ) 2 PO 4 , NH 4 NO 3 , KH 2 PO 4 , ZnSO 4 , and MgSO 4 .7H 2 O on pectinase production in the solid substrate. Firstly, a two-factorial design, Plackett-Burman design (PBD) was applied to screen the variables that significantly influenced the pectinase production. After finding the critical variables, 15 experimental runs were carried out using a Box-Behnken design (BBD) to derive a statistical model for optimizing the concentrations of the selected variables. The PBD model revealed that Satkara peel, urea, and (NH 4 ) 2 SO 4 significantly affected the pectinase production. RSM results indicated that the predicted response for pectinase production was in good agreement with experimental data (R 2 = 0.9836). Under the optimized condition of Satkara peel (8.4 g/L), urea (0.5 g/L), and (NH 4 ) 2 SO4 (2.7 g/L), the pectinase activity was predicted to be 0.6178 μmol/mL. In the present study, the experimental pectinase production achieved 0.6045 μmol/mL. The study revealed that optimization through RSM could improve the pectinase production from Satkara peel.

not availableBangladesh Agron. J. 2015, 18(2): 105-109

Food packaging is often made from plastic, which is usually obtained from non-renewable resources. The development of new technologies, like biocomposite films, has been driven in response to environmental concerns as well as consumer demands for eco-friendly, high-quality products derived from nature. Biocomposite films were prepared by incorporating taro mucilage, carboxymethyl cellulose (CMC), ZnO, glycerol, and black cumin seed (BCS) oil. The SEM results showed that the biocomposite films containing taro mucilage (TM), ZnO, and BCS oil had noticeably smoother surfaces. The FTIR analysis indicated the existence of a -OH group, N-H bond, alkaline group, C-C, C=N, C-H, C-O-H, and C-O-C bond formation, confirming the interaction of CMC, glycerol, BCS oil, ZnO nanoparticles, and TM. The results of TGA and DSC analysis suggest that incorporating ZnO nanoparticles, BCS oil, and TM into the CMC polymer matrix increased thermal stability. The addition of TM significantly increased water uptake capacity, antioxidative property, tensile strength, and elongation at break, with significantly decreased whiteness index and water solubility. The film inhibited the growth of Staphylococcus aureus and Escherichia coli as foodborne pathogens. The results suggest that the films can be potentially used as environment-friendly antioxidative and antimicrobial packaging films with additional research.

Physico-chemical properties and mineral contents of tropical fruits available at local market in Dhaka city were evaluated as fruits are the essential part of human diet to supply required micronutrient. Among the analyzed fruits, maximum and minimum amount of moisture was found in java apple (93.26±1.77%) and indian plum (66.86±1.81%) respectively. Mango contains highest amount of total soluble solids (15.20±0.81%) and total sugar (4.71±0.08%). Highest and lowest amount of vitamin C was found in guava (212.82±6.92 mg/100g) and java apple (10±1.77 mg/100g) respectively. Approximate energy value was found highest in indian plum (128.1±5.51kcal/100g) and lowest in green palmyra palm (27.7±2.64 kcal/100g). Indian plum (139.32±9.53mg/100g) and mango (34.03±6.81mg/100g) contain highest and lowest amount of sodium whereas rose apple (75.15±0.02mg/100g) and mango (10.23±1.94mg/100g) contain highest and lowest amount of potassium respectively. Heavy metals (As, Cd, Pb and Hg) were not detected in analyzed tropical fruits. This study suggests that the tropical fruits are enriched in micronutrients.

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