BUKU ABSTRAK - Universiti Putra Malaysia

Food
Potential Starter Culture to Inhibit Biogenic Amines Accumulation during Fish
Sauce Fermentation
Assoc. Prof. Dr. Fatimah Abu Bakar
Muhammad Zukhrufuz Zaman, Jinap Selamat and Jamilah Bakar
Faculty of Food Science and Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 8375; fatim@putra.upm.edu.my
This study was carried out to assess biogenic amines degradation activity of several bacteria isolated from
fish sauce, and examined their potential to inhibit amines accumulation during fish sauce fermentation. Eight
strains of bacteria were evaluated for their ability to degrade histamine, putrescine and cadaverine in a phosphate
buffer supplemented medium with 100 ppm of each amine. Bacillus amyloliquefaciens FS-05 and Staphylococcus
carnosus FS-19 were able to degrade histamine up to 59.9% and 29.1% from its initial concentration within
24 hours, respectively. Staphylococcus intermedius FS-20 and Bacillus subtilis FS-12 degraded putrescine and
cadaverine up to 30.4% and 28.9%, respectively. Most of the isolates were tolerant to salt concentration up to
15 %, temperature up to 45 ºC, and a wide range of pH (5-9. It is well known that histamine is the most active
amines in fish sauce, thus Staphylococcus carnosus FS-19 and Bacillus amyloliquefaciens FS-05 were used
as starter cultures and applied to fish sauce fermentation. Histamine content was reduced for about 27.7% and
15.4% by Staphylococcus carnosus FS-19 and Bacillus amyloliquefaciens FS-05, respectively. Both cultures
could also reduce other amines during fermentation. After 120 days of fermentation, the overall biogenic amines
content was 15.9% and 12.5% less in samples inoculated with Staphylococcus carnosus FS-19 and Bacillus
amyloliquefaciens FS-05, respectively, as compared to control samples. Biogenic amine degradation activity of
the bacteria was considered as strain rather than species specific. Moreover, the findings of this study emphasized
a potential benefit of bacteria with amines oxidase activity to inhibit biogenic amines accumulation when applied
as starter cultures in fish sauce fermentation and perhaps other fermented foods.
Keywords: Biogenic amines, amines degrading bacteria, histamine, fish sauce
Effect of Different Pineapple Juice (Ananas comosus L.) Preparation on the
Microstructure, Staling and Textural Properties of Wheat Bread
Assoc. Prof. Dr. Lasekan Olusegun
Faculty of Food Science and Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 8535; lasekan@food.upm.edu.my
The effect of adding different pineapple juice preparations on the microstructure, staling and textural
properties of wheat bread were investigated. The loaves quality, crust and crumb color, and staling profile
(crumb firmness, enthalpy) during storage were monitored. The micro-structural differences of crumbs were also
examined using microtome and Scanning Electron Microscopy (SEM). Results revealed that the specific volume
of fresh loaves baked with concentrated pineapple juice (PJC) bread was not significantly (P = 0.05) different
from that of control wheat bread (WB). Likewise, firmness of crumbs, number of crumb cells, area air cell, bake
loss, volume yield, and crust and crumb color of the freshly baked PJC bread were not significantly (P = 0.05)
different from the control WB. However, during storage, the retro gradation of starch in pineapple bread crumbs
(PJC and pineapple juice [PJ] bread) was significantly (P = 0.05) retarded as compared with the control WB.
While there was no significant (P = 0.05) textural differences between the crumbs of freshly produced PJC bread
and the crumb of the control WB, staled breads revealed significant textural changes in their crumbs. Microtome
and SEM revealed the presence of many starch granules on the surface of pore walls in the control WB, whereas
the PJC bread contained starch gels cemented between starch granules. Gluten nets were found to be uniform and
more oriented in the control WB than in the PJC bread. However, same gluten nets were dense and non-uniform
in the PJ bread.
Keywords: Pineapple juice concentrate, wheat bread, texture, microstructure, staling
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