Extraction of selected bioactive compounds from averrhoa bilimbi and their thermal stability during spray drying

A. bilimbi (ver. name Belimbing Buluh) contains many useful bioactive compounds leading to various activities such as antioxidant, anti-diabetic and anti-tuberculosis. Analysis of the A. bilimbi extracts using UHPLC-QTOF-MS, qualitative analysis and identification using Metlin Database shows the presence of three compounds; nicotinic acid, pantothenic acid and catechin. Following the mass spectrometry and UV spectra confirmation, the nicotinic acid, pantothenic acid and catechin can be used as a marker of A. bilimbi. Recovery of bioactive compounds from the plant materials are normally performed via extraction. The yield of bioactive compound in the extract is dependent on the solvent used, extraction method and condition. In this work, ultrasonic assisted extraction was studied. The highest extraction yields of 0.28 mg/g DW nicotinic acid, 1.00 mg/g DW pantothenic acid and 0.22 mg/g DW catechin from A. bilimbi were obtained at temperature of 30 °C, sonication power of 0.070 W/ml, time of 30 min, solvent to solid ratio of 8 ml/g and methanol concentration of 40%. Bioactive compounds are known to suffer from a degradation process when exposed to high temperature over a long period, which is often the case during the extraction and powder making process. The recovery process is often accomplished at slightly elevated temperatures, thus it is vital to understand the loss of bioactive compounds due to thermal degradation before the mitigating method can be formulated. The results showed nicotinic acid, pantothenic acid and catechin degradation followed the firstorder kinetics model. Pantothenic acid showed the lowest degradation rate constant, followed by nicotinic acid and catechin for all studied temperature, indicating a slowest degradation. The thermal degradation activation energy of nicotinic acid, pantothenic acid and catechin were 43.85 kJ/mol, 58.86 kJ/mol, and 21.27 kJ/mol, respectively. Pantothenic acid has the highest activation energy which implies that the compound is more sensitive to temperature change. Microencapsulation can provide a physical barrier between the core compound and the other components of the product which would then provide a better heat protection during spray drying. Microencapsulation of bioactive compounds from A. bilimbi by spray drying using maltodextrin resulted in a high retention of nicotinic acid, pantothenic acid and catechin. Results obtained from this work demonstrated that the best operating conditions for spray drying of A. bilimbi extract whereby the highest retention of nicotinic acid, pantothenic acid and catechin are 10% maltodextrin DE18 and air inlet temperature 140 °C

Effects of Drying Methods on the Quality Parameters of Dried Manis Terengganu Melon (Cucumis melo)

  The objective of this study was to identify the suitable drying methods for preservation of immature Manis Terengganu melon by using different temperatures which are 40 °C, 50 °C and 60 °C. The osmotically pre- treated samples were dried by using three types of convective dryer; cabinet dryer, oven dryer and rotary dryer. The drying time and drying rates were determined through drying curve. Rotary dryer had the shortest drying time and drying rates followed by cabinet dryer and oven dryer. The quality parameters on dried melon were identified. The range of water activity achieved for dried melon was 0.46-0.52. The hardness and chewiness of dried melon showed significantly difference between fresh and dried sample. The browning absorbance of dried melon at 420 nm for each equipment at temperature 50 °C showed significant difference at p<0.05. Rotary dryer at 50 °C was preferred as the suitable drying equipment to dry melon in terms of time consumption as well as produced acceptable physicochemical quality of dried melon. Keywords: Cucumis melo, drying, osmotic dehydration, quality parameter

Influence of Solvent Polarity and Conditions on Extraction of Antioxidant, Flavonoids and Phenolic Content from Averrhoa bilimbi

This paper presents the influence of solvent polarity and extraction conditions on the extraction of total flavonoid, total phenolic and antioxidants from Averrhoa bilimbi. The experiment was performed using a different solvent at different extraction conditions, including extraction time (15-240 min), temperature (30-70 °C) and agitation speed (50-300 rpm). Results showed that yields of extraction varies with solvent polarity. Extraction using 50% aqueous methanol gives the highest antioxidant activity and flavonoid content. The highest total flavonoid content (193.3 µg quercetin equivalent/g dry weight), total phenolic content (717.8 µg gallic acid equivalent/g dry weight) and antioxidant activity (77%) was achieved using 50% methanol, at 70 °C and agitation speed of 300 rpm. This work may be useful for obtaining higher bioactive compounds during the extraction process of A. bilimbi

Physical and Functional Properties of Banana Pseudostem Flour and its Effect on the Quality (Texture and Microstructure) of Formulated Bread

The objectives of this study were to compare physical and functional properties of banana pseudostem flour (BPF) with commercial wheat flour (CWF). The texture and microstructure qualities of composite breads formulated with partial substitution (10%) of CWF by BPF, as well as the addition of hydrocolloids, i.e. xanthan gum or sodium carboxymethyl cellulose (Na CMC), were also investigated. The microstructure of the bread crumb was evaluated using scanning electron microscope. When compared to CWF, water and oil holding capacities for BPF was significantly (p < 0.05) higher, whereas bulk density, water activity, and lightness (CIE L*) value for BPF was significantly (p < 0.05) lower. Bread formulated with BPF without addition of hydrocolloids showed harder bread crumb than the bread containing BPF and hydrocolloids. However, the addition of Na CMC into the composite bread formulation showed to improve the crumb softness, whereby the crumb appeared to have more continuous protein network and larger gas cells. Therefore, composite bread with added Na CMC is suitable to be utilized in processing of good quality bread.

Effect of extraction solvents and drying conditions on total phenolic content and antioxidant properties of watermelon rind powder

The objective of the present study was to determine the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant properties, i.e. 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferric reducing antioxidant potential (FRAP) assay, of red- and yellow-fleshed watermelon rind powders prepared using different drying conditions (hot-air oven drying at 40 and 60°C and freeze drying). All the samples were subjected to four different solvent extract using water, methanol, ethanol and acetone prior analyses. Water extract from red- and yellow-fleshed watermelon rind powders presented highest value for TPC and TFC. However, methanol extract samples showed highest value for antioxidant properties (DPPH and FRAP) followed by acetone, ethanol and water extract. By comparing the drying conditions, all samples dried using hot-air dryer at 40 and 60°C had significantly higher (p<0.05) in TPC value than the samples dried using freeze dryer. However, samples dried using freeze dryer showed highest in DPPH and FRAP values. The present obtained results would be useful to the food and pharmaceutical industries for developing of functional ingredients

Influence of Solvent on Extraction of Antioxidant, Flavonoids and Phenolic Content from Averrhoa bilimbi

This paper presents the influence of solvent polarity and extraction conditions on the extraction of total flavonoid, total phenolic and antioxidants from Averrhoa bilimbi. The experiment was performed using a different solvent at different extraction conditions, including extraction time (15-240 min), temperature (30-70 °C) and agitation speed (50-300 rpm). Results showed that yields of extraction varies with solvent polarity. Extraction using 50% aqueous methanol gives the highest antioxidant activity and flavonoid content. The highest total flavonoid content (193.3 µg quercetin equivalent/g dry weight), total phenolic content (717.8 µg gallic acid equivalent/g dry weight) and antioxidant activity (77%) was achieved using 50% methanol, at 70 °C and agitation speed of 300 rpm. This work may be useful for obtaining higher bioactive compounds during the extraction process of A. bilimbi