Spore-forming bacteria, Bacillus sp., frequently been associated with the contamination of rice and other starchy
products. Spores are more resistant to antimicrobial treatments than its vegetative cells. The extract of Indonesian bay
leaf (Syzygium polyanthum L.) was assessed for its antibacterial and sporicidal activities against vegetative cells and
spores of B. cereus isolated from rice (25 strains). The results showed that S. polyanthum L. extract was able to inhibit
the growth of vegetative cells of all B. cereus isolates with MICs ranged from 0.16 to 0.63 mg/mL and can kill with
MBCs ranged from 0.31 to 2.50 mg/mL. The bactericidal endpoint for B. cereus BC-NP.8 in time kill curve was at 1.25
mg/mL (8× MIC) after 4 h of incubation while for B. cereus ATCC 33019 was at 2.50 mg/mL (8× MIC). The sporicidal
activity of S. polyanthum L. extract was not affected by different temperatures treatment and alteration of the pHs of
extract. Therefore, this indicates that the extract was stable after exposed to pH3, 7 and 10 as well as temperature
of 50, 80, and 121°C. Observation under on scanning electron microscope the structure of the B. cereus ATCC 33019
spores was ruptured after being treated with 1% (w/v) S. polyanthum L. extract for 1 h. In conclusion, S. polyanthum L.
extract had antibacterial and sporicidal activity against vegetative cells and spores of B. cereus isolated from rice.
Rambutan fruit is an exotic fruit and is getting popular worldwide. However, there is usually a glut of rambutan fruit
every year which leads to wastage, especially those from underutilized wild types. Transforming the fruit into various
products could reduce the wastage. Before doing so, the characteristics of the fruit should be available. Hence, the main
aim of this study was to investigate the physicochemical properties of various cultivars of rambutan. The results showed
that rambutan fruit comprises between 38.6-70.8% peel, 19.1-45.9% pulp and 8.3-20.3% seed. On average, it has a pH,
titratable acidity and total soluble solids of 4.18-5.44, 0.10-0.52% as citric acid and 13.78-16.67 °Brix, respectively.
The fruit contains high sugar contents, mainly contributed by sucrose (5.38-10.01%), fructose (1.75-3.18%) and glucose
(1.72-2.43%). Citric acid was the major organic acid found in the fruit and wild type, WT1, contained the highest level.
Some rambutan cultivars including Clone R3, WT1 and wild type, WT2, possess greater concentrations of ascorbic acid
compared to other tropical fruits. With these findings, various types of food products could be derived from rambutan
fruit based on their physicochemical properties.
Sweatings, the exudates that leach out from fermenting fruits during rambutan fruit fermentation are considered as
a waste by-product and are allowed to be drained off. This could lead to a pollution problem. Besides, it is a waste if
the sweatings are possible to be transformed into food products and ingredients. However, prior transformation, the
fundamental knowledge of the sweatings should be understood. Hence, the main aim of this study was to investigate
the physicochemical properties of sweatings as affected by fermentation time and turning intervals during natural
fermentation of rambutan fruits. In this study, peeled rambutan fruit was fermented for 8 days and turned. Different
batches of the fruits were turned every 24, 48 or 72 h and sweatings from the process were collected and analyzed.
The results showed that fermentation time significantly reduced (p<0.05) the yield, pH and sucrose content of the
sweatings by 79-84%, 32-33%, 76.5-80.8%, respectively. Fermentation time also significantly increased (p<0.05) the
titratable acidity, total soluble solids, fructose, glucose, total sugar, citric acid, lactic acid, acetic acid and ascorbic
acid contents of the sweatings by 5.6-6.0, 1.5-1.6, 2.4-2.6, 2.1-2.5, 1.0-1.1, 5.7-6.5, 2.4-2.6, 2.1-2.5 and 2.6-2.8 folds,
respectively. However, turning intervals did not significantly affect (p>0.05) the physicochemical properties of the
sweatings. High concentrations of sugars and organic acids allow the sweatings to have a balance of sweet and sour
taste and they are suitable to be used in the production of syrup, soft drinks, jam, jelly, marmalade and vinegar.