Chemicals
Digestive enzymes and bile salts were purchased from
Sigma Chemical Co (St Louis, MO, USA). A pepsin
digestion mixture was prepared by suspending 16 g
pepsin (P-7000, from porcine stomach mucosa) in
100 ml 0.1 M HC1. The pancreatin-bile extract mixture
contained 4 g pancreatin (P-1750, from porcine
pancreas) and 25 g bile extract (B-8631, porcine) dissolved
in 1 litre of 0.1 M NaHCO,. Miller et al (1981)
did not specify in detail the enzymes used.
A protein precipitation solution was prepared by
mixing 100 g trichloroacetic acid, 100 g hydroxylamine
and 100 g of 370 g litre-' HC1 and making up to 1 litre.
The chromagen solution contained 250 mg of bathophenanthroline
sulphate dissolved in 1 litre of 2 M
sodium acetate. This solution was stored, lightprotected,
for at maximum of 1 week. Iron standards,
containing 0.1, 0.2, 0.4, 0.8 and 1.6 pg Fe(I1) ml-' in
10 g litre-' HCl were used for establishing a calibration
curve.
All chemicals (Merck, Darmstadt, Germany) were of
analytical grade. Milli Q water (Millipore, Bedford,
USA) or distilled water was used throughout the trials
Gastric stage
The sample (10 g) was mixed with 80 g water in a
250 ml Erlenmeyer flask (height 13.5 cm, diameter of
base 8.5 cm). The pH was adjusted to 2.0 by adding 6 M
HCl. The pH was checked after 15 rnin and if necessary
readjusted to 2.0. In the method of Miller et al (1981)
readjustment of the pH was not mentioned.
Freshly prepared pepsin solution (3 g) was added and
the sample was made up to 100 g with water. After
mixing the sample was incubated at 37°C in a shaking
waterbath for 2 h. The recommended waterbath settings
(not specified by Miller et a1 (1981)) were 100-120
strokes min-' and an arm movement of 2 cm.
The gastric digests were stored in ice for 90 min
during which the titratable acidity was measured in an
aliquot. Lowering the temperature of the digest was not
included in the original method of Miller et al(l981)
คุณหมอคร่า หนูพยายามอ่านแล้วแต่ไม่เข้าใจว่ามันทำอย่างไรเนื่องจากจะนำไปพรีเซ้นให้เพื่อนหน้าห้องแต่ก็ไม่เข้าใจสักทีค่ะ คุณหมอช่วยทีนะคร่า
ขอบคุณคุณหมอ สุดหล่อ ถามอะไรคุณหมอก็ตอบหมด ขอบคุณนะคร่า |
