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- Điều hướng trang này:
- Extraction of coconut water
- Production of freeze-concentrated coconut water
| MATERIAL AND METHODS
Chemicals and reagents All chemicals used in this study were of analytical grade, except for methanol, glucose, fructose, and sucrose, which are HPLC grade. All the chemicals were purchased from Sigma-Aldrich Co., St. Louis, USA. Bradford Protein Assay kit was purchased from Bio-Rad Laboratories, Hercules, USA. Coconuts Coconut fruits of two different maturity stages were used in this study. Green coconuts (GC) used were of 8–9 months old and contained a soft thin (2–4 mm) layer of coconut flesh. Mature coconuts (MC) used were of ≥12 months old and contained a hard thick (~10 mm) layer of coconut flesh. All coconuts (from coconut variety Malayan Tall) were purchased from a local commercial dealer (Anba Coconuts) located at Abu Siti Lane, Penang, Malaysia, between the month of January and April, 2015. Extraction of coconut water Surface of the coconut husks was cleaned with distilled water and 1% bleach (Clorox) before a stainless-steel knife was used to perforate the fruit mesocarp. Coconut water was manually extracted from the coconut fruit and filtered through muslin cloth. The filtered coconut water from several fruits (5 to 10 coconuts with similar maturity age) was pooled in a 2 L Schott bottle and kept temporary in an icebox filled with ice packs. All coconut water prepared was processed on the same day of purchase and extraction. Three batches of coconut water were prepared for each maturity stage. Production of freeze-concentrated coconut water Two types of freeze-concentration of coconut water were prepared; freeze-concentrated coconut water prepared from GC (FGC) and MC water (FMC). Freeze-concentration of coconut water was carried out according to the method as described by Lo et al. (2007) with slight modifications. Extracted coconut water was filled into polypropylene plastic casings (18 cm × 12 cm) that was then sealed and subjected to a rapid chilling treatment to –18°C using an air blast freezer (Irinox, Italy). Each plastic casing can be filled with 200 mL of coconut water. The process of rapid chilling from ambient temperature to -18°C took around 30 min to complete. At the end of this process the core temperature of the coconut water-ice mixture was -8°C. The coconut water-ice mixture was then transferred into a domestic freezer (-18°C; Sharp, Malaysia) and stored for 24 h, whereby the hardening and completion of ice formation occurred. At this stage, separation of ice and unfrozen phase consisted mainly of freeze-concentrated coconut water was evident. A small opening 16/ J. Agrobiotech. Vol. 8 (1), 2017, p. 13–24. was made at one end of the plastic casing to allow the flow of the concentrated coconut water into a volumetric flask. This process of thawing was performed at room temperature and stopped once the total soluble solid (TSS) of the thawed coconut water reached double the initial TSS value. The TSS reading was taken every 5 min and the thawing process took 50 min to complete. The production trials were repeated three times to yield standardised freeze-concentrated coconut water with predefined, i.e. double, TSS value. tải về 221.3 Kb. Chia sẻ với bạn bè của bạn:
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