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Assessment of physicochemical properties of coconut water
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- Điều hướng trang này:
- Assessment of composition of coconut water Protein content
- Crude fat content
| Assessment of physicochemical properties of coconut water
Total soluble solids (TSS) TSS was expressed as °Brix and measured with a digital refractometer (Hanna Instruments Inc., H196801, Cluj- Napoca, Romania) at 25°C (Tan et al. 2014). pH The pH of coconut water was determined using pH electrode (Mettler-Toledo, Inlab Semi Micro Electrode, Greifensee, Switzerland) attached to a pH meter (Mettler-Toledo, S40 SevenMulti TM , Greifensee, Switzerland). Calibration on the pH meter with buffer solution of pH 4.01, 7.00, and 9.21 was done prior to measurements. Turbidity Turbidity of the coconut water was determined using a turbidimeter (Hach, 2100P, Loveland, USA) as described by González-Neves et al. (2014). Calibration on the turbidimeter with Formazin Turbidity Standard solutions of <0.1, 20, 100, and 800 NTU was done prior to measurements. Turbidity value was expressed in Nephelometric Turbidity Units (NTU). Assessment of composition of coconut water Protein content Protein content of the samples was determined according to Bradford Method as described by Tan et al. (2014). Bovine serum albumin (BSA) was used as standard. Measurement of absorbance was carried out using UV-Vis spectrophotometer (Shimadzu, UV-1650 PC, Nakagyo-ku, Japan) at wavelength of 595 nm. Relative measurement of protein concentration can be obtained by comparing with the BSA standard curve. Crude fat content Crude fat content in coconut water samples was determined by AOAC Method 934.01, with slight modifications (AOAC, 1995). The weight of an empty round bottom flask after 1 h of oven-drying and 30 min of cooling in desiccators was recorded. Coconut water (10 mL) was placed in a separating funnel and mixed well with 10 mL of petroleum ether. The separating funnel was inverted slowly and the stopcock was opened to release the pressure. A few drops of the mixture were placed on the filter paper (Whatman Filter Paper Grade 41). Extraction was considered complete when there was no trace of oil observed on the filter paper. The petroleum ether was then collected in round bottom flask and induced to the Soxhlet extractor to extract fat. The solvent was siphoned and removed from the flask until almost dried. The flask was then heated in an oven at 105°C (Memmert, UM 600, Schwabach, Germany) for 1 h and kept in desiccators for 30 min before the weight of the flask was measured. The crude fat content was calculated and expressed in % (w/v) using the following equation: Crude fat content = [(w 1 – w 2 )/V] × 100% (1) where, w 1 is the weight of flask with fat (in g), w 2 is the weight of empty flask (in g), and V is the volume coconut water used (in mL) tải về 221.3 Kb. Chia sẻ với bạn bè của bạn:
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