Abstract: The aim of research was to define the relations
between volatile compounds, some parameters (pH, titratable acidity
(TA), total soluble solid (TSS), lactic acid bacteria count) and
consumer preference of commercial fermented milks. These relations
tend to be used for controlling and developing new fermented milk
product. Three leading commercial brands of fermented milks in
Thailand were evaluated by consumers (n=71) using hedonic scale
for four attributes (sweetness, sourness, flavour, and overall liking),
volatile compounds using headspace-solid phase microextraction
(HS-SPME) GC-MS, pH, TA, TSS and LAB count. Then the
relations were analyzed by principal component analysis (PCA). The
PCA data showed that all of four attributes liking scores were related
to each other. They were also related to TA, TSS and volatile
compounds. The related volatile compounds were mainly on
fermented produced compounds including acetic acid, furanmethanol,
furfural, octanoic acid and the volatiles known as artificial fruit
flavour (beta pinene, limonene, vanillin, and ethyl vanillin). These
compounds were provided the information about flavour addition in
commercial fermented milk in Thailand.
Abstract: The objective of the study was to select the survival of
probiotic strains when exposed to acidic and bile salts condition. Four
probiotic strains Lactobacillus casei subsp. rhamnosus TISTR 047,
Lactobacillus casei TISTR 1500, Lactobacillus acidophilus TISTR
1338 and Lactobacillus plantarum TISTR 1465 were cultured in
MRS broth and incubated at 35ºC for 15 hours before being inoculated
into acidic condition 5 M HCl, pH 2 for 2 hours and bile salt 0.3%,
pH 5.8 for 8 hour. The survived probiotics were counted in MRS agar.
Among four stains, Lactobacillus casei subsp. rhamnosus TISTR 047
was the highest tolerance specie. Lactobacillus casei subsp.
rhamnosus TISTR 047 reduced 6.74±0.07 log CFU/ml after growing
in acid and 5.52±0.05 log CFU/ml after growing in bile salt. Then,
double emulsion of microorganisms was chosen to encapsulate before
spray drying. Spray drying was done with the inlet temperature 170ºC
and outlet temperature 80ºC. The results showed that the survival of
encapsulated Lactobacillus casei subsp. rhamnosus TISTR 047 after
spray drying decreased from 9.63 ± 0.32 to 8.31 ± 0.11 log CFU/ml
comparing with non-encapsulated, 9.63 ± 0.32 to 4.06 ± 0.08 log
CFU/ml. Therefore, Lactobacillus casei subsp. rhamnosus TISTR 047
would be able to survive in gastrointestinal and spray drying condition.