Encapsulation of phenolic-rich extract from banana (Musa cavendish) peel.

Banana peel, a by-product rich in phenolics and other bioactive compounds, has great potentials as a natural preservative or healthy food ingredient. However, the instability of bioactive compounds derived from banana peel limits their applications, and as such encapsulation is necessary to improve their stability and widen their applications. This study investigated the impact of spray drying conditions and coating materials on the physical, phytochemical, and antioxidant properties of the peel extract to identify the most suitable encapsulation process. The results showed that inlet temperature (ranging from 140 to 180 °C) and feeding rate (3-15 mL/min) did not significantly affect the total phenolic content (TPC) and antioxidant capacity but influenced the moisture content and recovery yield of the powder. The ratio of dry matter in fresh extract-to-coating material (DM-to-CM) (1:1-1:7 (w/w)) did not affect the moisture content. However, it affected the TPC, antioxidant properties, and recovery yield of the powder. Finally, the type of coating materials did not significantly affect TPC and antioxidant properties, but other physical properties, dopamine levels and recovery yield. The most suitable encapsulation conditions were identified as an inlet drying temperature of 150 °C, a feeding rate of 9 mL/min, a ratio of DM-to-CM of 1:1 (w/w), and coating with a combination of maltodextrin M100 and gum acacia. Powder prepared under the most suitable conditions had a spherical shape with a rough surface and had stable TPC under storage conditions of 40 °C for 4 weeks. It also has ideal physical, phytochemical and antioxidant properties and is suitable for further applications.

Maximising recovery of phenolic compounds and antioxidant properties from banana peel using microwave assisted extraction and water.

Banana peel is rich in phenolic compounds and is generally considered as waste. This study aimed to maximise recovery of phenolics from banana peel using water via microwave assisted extraction. The impact of various parameters including pH of solvent, sample to solvent ratio, irradiation time with/without cooling periods, and irradiation power were investigated individually. Following this, extraction conditions were further optimised using Response Surface Methodology. The results revealed that the extraction efficiency can be significantly improved by reducing the pH of water, increasing microwave power and time. However, cooling time during irradiation did not affect the extraction efficiency. Optimal conditions were identified at pH of 1, ratio of 2:100 g/mL, 6 min irradiation, and microwave power of 960 W. Under these optimal conditions, approximately 50.55 mg phenolics could be recovered from 1 g dried peel. These conditions are recommended for recovery of phenolic compounds from banana peel for further utilisation.

Fruit characteristics, phytochemical and antioxidant properties of blueberry ash (Elaeocarpus reticulatus).

Blueberry ash (Elaeocarpus reticulatus Sm.) fruit has potential for human nutrition, but there is limited information on this fruit. This preliminary study aimed to characterise blueberry ash fruit and examine the influence of extraction solvents on its phytochemical and antioxidant properties. Blueberry ash fruit is dark blue in colour and is a stone fruit of small size (7 mm) and light weight (0.2 g). However, it has a high portion of flesh (60% of fruit weight), which is edible and can be a potential source of phytochemicals. Water, ethanol, acetonitrile, acetone, and their combination were tested for extraction of phytochemicals from flesh of this fruit. Water or absolute organic solvent was ineffective for extraction of phenolic compounds from this fruit, but mixtures of water and organic solvents were more effective, and 50% acetone was the most suitable extraction solvent. Extraction with 50% acetone, this fruit was found to contain high levels of total phenolic content, flavonoids, proanthocyanidins, and anthocyanins (104 mg GAE/g, 155 mg RUE/g, 78 mg CE/g, and 119 mg CGE/g, respectively). In addition, this fruit was found to possess potent antioxidant properties. Therefore, this fruit should be further studied for identification of its phenolic compounds and further tested for their biological properties.

Cytosolic carboxypeptidase 1 is involved in processing α- and ß-tubulin.

The Purkinje cell degeneration (pcd) mouse has a disruption in the gene encoding cytosolic carboxypeptidase 1 (CCP1). This study tested two proposed functions of CCP1: degradation of intracellular peptides and processing of tubulin. Overexpression (2-3-fold) or knockdown (80-90%) of CCP1 in human embryonic kidney 293T cells (HEK293T) did not affect the levels of most intracellular peptides but altered the levels of α-tubulin lacking two C-terminal amino acids (delta2-tubulin) ≥ 5-fold, suggesting that tubulin processing is the primary function of CCP1, not peptide degradation. Purified CCP1 produced delta2-tubulin from purified porcine brain α-tubulin or polymerized HEK293T microtubules. In addition, CCP1 removed Glu residues from the polyglutamyl side chains of porcine brain α- and ß-tubulin and also generated a form of α-tubulin with two C-terminal Glu residues removed (delta3-tubulin). Consistent with this, pcd mouse brain showed hyperglutamylation of both α- and ß-tubulin. The hyperglutamylation of α- and ß-tubulin and subsequent death of Purkinje cells in pcd mice was counteracted by the knock-out of the gene encoding tubulin tyrosine ligase-like-1, indicating that this enzyme hyperglutamylates α- and ß-tubulin. Taken together, these results demonstrate a role for CCP1 in the processing of Glu residues from ß- as well as α-tubulin in vitro and in vivo.

Comparison of two dengue NS1 rapid tests for sensitivity, specificity and relationship to viraemia and antibody responses.

BACKGROUND: Dengue is a major public health problem in tropical and subtropical countries. Rapid and easy diagnosis of dengue can assist patient triage and care-management. The detection of DENV NS1 on rapid lateral flow tests offers a fast route to a presumptive dengue diagnosis but careful evaluations are urgently needed as more and more people use them. METHODS: The sensitivity and specificity of the Bio-Rad NS1 Ag Strip and SD Dengue Duo (NS1/IgM/IgG) lateral flow rapid tests were evaluated in a panel of plasma samples from 245 Vietnamese patients with RT-PCR confirmed dengue and 47 with other febrile illnesses. RESULTS: The NS1 rapid tests had similar diagnostic sensitivities (respectively 61.6% and 62.4%) in confirmed dengue cases but were 100% specific. When IgM/IgG results from the SD Dengue Duo were included in the test interpretation, the sensitivity improved significantly from 62.4% with NS1 alone to 75.5% when NS1 and/or IgM was positive and 83.7% when NS1 and/or IgM and/or IgG was positive. Both NS1 assays were significantly more sensitive for primary than secondary dengue. NS1 positivity was associated with the underlying viraemia as NS1-positive samples had a significantly higher viraemia than NS1-negative samples. CONCLUSIONS: These data suggest that the NS1 test component of these assays are highly specific and have similar levels of sensitivity. The IgM parameter in the SD Duo test improved overall test sensitivity without compromising specificity. The SD Dengue Duo lateral flow rapid test deserves further prospective evaluation in dengue endemic settings.