2.4 เตรียมความพร้อมของขุยมะพร้าว2.4. Preparation of coconut husk
2.4.1 การเก็บและการจัดเตรียมขุยมะพร้าวแกลบมะพร้าวที่ได้รับจากตลาดในประเทศในหาดใหญ่, สงขลา, ไทยและเคลื่อนย้ายไปยังภาควิชาอาหารเทคโนโลยีมหาวิทยาลัยสงขลานครินทร์หาดใหญ่, ไทย 2.4.1. Collection and preparation of coconut husk
Coconut husk was obtained from a local market in Hat Yai,
Songkhla, Thailand and transported to the Department of Food
Technology, Prince of Songkla University, Hat Yai, Thailand. Husk
was prepared following the method of Vazquez-Torres, Canche-
Escamilla, and Cruz-Ramos (1992). The obtained powder was
placed in a polythene bag, sealed and kept at room temperature
until use.
2.4.2. Preparation of ethanolic extract from coconut husk
Coconut husk powder was subjected to extraction according to
the method of Santoso, Yoshie-Stark, and Suzuki (2004). Dried
extract was powdered using a mortar and pestle and was kept in an
amber bottle and stored in a desiccator at room temperature
(28e30
C) until use. The obtained powder was referred to as
‘ethanolic extract from coconut husk, EECH’. The yield of EECH was
48.5 g 100 g
À1
husk powder.
2.4.3. Determination of total phenolic content
Total phenolic content was determined using a colorimetric
method using the FolineCiocalteau reagent (Singleton, Orthofer, &
Lamuela-Raventos, 1999). Total phenolic content in EECH was
calculated from a standard curve of tannic acid (0.01e0.1 mg L
À1
)
and expressed as g tannic acid equivalent kg
À1
dry matter
(Singleton et al., 1999).
2.4.4. Determination of tannic acid content
Tannic acid in EECH was determined using an HPLC equipped
with a variable wavelength detector (VWD) following the method
of Tian et al. (2009) with slight modifications. The HPLC system
consisted of an Agilent 1100 series HPLC (Alginet, Wilmington, DE,
USA), quaternary pump with the seal wash option, degasser, sol-
vent, cabinet and preparative auto-sampler with thermostat
equipped with a diode array detector. The separations were done
using a Hypersil ODS C18 4.0 Â 250 mm, 5
m
m column
(ColeeParmer, London, UK). HPLC conditions were as follows:
mobile phase: 0.4 g 100 mL
À1
formic acid: acetonitrile (85:15), flow
rate: 0.8 ml min
À1
, temperature: 25
C. Detection was carried out at
280 mm. The concentration of extracts was 25 mg ml
À1
and each
injection volume was 20
m
l. Standard tannic acid was used for peak
identification
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