หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Preservatives on Raw Milk Components Analyzed by
Infrared Spectrophotometry)
ผู้เขียน:
Nitima Chalermsan, 
ดร.ประวีร์ วิชชุลตา, รองศาสตราจารย์
, Pornsri Chirattanayuth, Sirinporn Sintuwanit, ดร.สมจิต สุรพัฒน์
, ดร.อรุณี อิงคากุล, ผู้ช่วยศาสตราจารย์
สื่อสิ่งพิมพ์:pdf
Abstract
The effects of preservatives on milk component analysis using infrared spectrophotometric
method were investigated. Raw milk samples from sixty farms were collected. Thirty ml from each milk
sample was kept in plastic vial containing either 0.02 % bronopol, 0.40 % potassium dichromate or
sodium azide tablet (0.03 %) as preservatives. All milk sub-samples were stored under refrigeration at
4?C then analyzed for milk components at 0, 7, 14, 21 and 28 days of storage. Control samples (without
preservative) were analyzed only at 0 day. The means of milk fat, protein, lactose and total solids for the
non-preserved milk at 0 day storage were 4.10, 3.00, 4.84 and 12.65 %, respectively. Analysis result of
milk components among the control, milk preserved with bronopol and milk preserved with potassium
dichromate showed no statistical different at 0 day storage. At this storage day, however, raw milk with
sodium azide had lower (P<0.01) fat, protein and total solids. Prolonged storage of milk preserved with
the three chemicals over 7 days illustrated a potential decline in most components analyzed. Changing
pattern of the analysis results of milk preserved with the three respective chemicals at 28 days when
compared with those of 0 day storage were -5.39, -4.79 and -8.36 % for fat, -0.30, -1.17 and +0.13 % for
protein, -1.22, -0.91 and -0.91 % for lactose, and -2.45, -2.29 and -3.11 % for total solids. It is concluded
that bronopol, potassium dichromate and sodium azide are effective preservatives for raw milk
component analysis by infrared spectrophotometry. However, commercial sodium azide in the tablet
form contains sodium salt, which can depress milk component analysis result. In addition, preserved raw
milk samples should be kept under refrigeration at 4?C and analyzed within 7 days.