The drying of Piper betle Linn (betel) leaf extract using a lab scale spray dryer was simulated using Computational Fluid Dynamics (CFD). Three different turbulent models (standard k-ε, RNG k-ε and realizable k-ε) were used in the present study to determine the most suitable model for predicting the flow profile. Parametric studies were also conducted to evaluate the effect of process variables on the final moisture content. Four different initial droplet sizes (36, 79, 123 and 166 μm) were tested with four sets of combination of hot air temperature (140 and 160°C) and feed rate (4, 9.5 and 15 ml/min). It was found that standard k-ε is the most suitable turbulent model to predict the flow behaviour Moreover, the lowest final moisture content present in samples was obtained at 140°C and a feed rate of 15.0 ml/min.
The study was carried out to evaluate short-term administration of Gelam honey. A single oral
administration of the honey at a dose of 5000 mg/kg body weight on male Sprague Dawley rats
(test group) for 14 days did not produce any signs of toxicity, behavioral changes, mortality, changes on gross appearance or histopathological changes of internal organs. The examinations
of signs, animal behavior and health monitoring showed no abnormalities in the test group as
compared to the rats unfed with the honey (control group). The test group had progressive increased both body weight and in the meal pattern analysis. However, triglycerides level was found significantly decreased in the test group. It suggested that the honey might have a decent effect in controlling the blood triglyceride level. Polyphenol contents in the honey may play the role to reduce the trigyceride level. Biochemical test for aspartate aminotransferase (AST), alanine transaminase (ALT), urea, creatinine, cholesterol and glucose of rats in the test group were in the normal range compared to the control. There were no significant changes in the absolute and relative organ weight between the two groups. As a conclusion, tested dose of Gelam honey is safe and has medical potential. Meanwhile, lethal dose (LD50) of the honey was found to be greater than 5000 mg/kg body weight. Long period of Gelam honey consumption should be conducted to observe and confirm those effects.
In this study polymerase chain reaction (PCR) was used to identify yeast in domestic ragi obtained
from two local markets in Sarawak and Pahang. These ragi are normally used as a dry starter in food fermentation (tapai) for Pahang (ST2) and Sarawak (ST3) and tuak (ST1) which is an alcoholic drink in Sarawak. Universal primer, NL1 and NL4 were used as a primer in this study to amplify D1/D2 fragment. Based on the result from the sequencing and after the BLAST search of the nucleotide sequences, the strain was confirmed as Candida glabrata (FN424108.) partial 26S rRNA gene, strain IMUFRJ 51955 for ST1, Saccharomyces cerevisiae(EU285514.1) isolate 35 26S ribosomal RNA gene, partial sequence for ST2 sample and Candida glabrata (FN393990.1) partial 26S rRNA gene, strain MUCL 51244 for ST3. All these strains were found in domestic ragi used for food fermentation.
This study investigated the protein quality of two sets of Roselle seeds processed differently (dried and boiled). Twenty weanling Sprague Dawley rats were used to conduct the growth and nitrogen balance studies. Rats were fed with 10% (w/w) protein from dried (DS) and boiled (BS) Roselle seeds powder for 4 weeks. Casein was used in this study as a standard reference protein. There was a significantly higher (p < 0.05) food intake and weight gain by rats fed with BS compared with DS. In the growth study, there was no significant difference (p < 0.05) in protein efficiency ratio (PER) and net protein ratio (NPR) of BS compared to DS, but it was significantly different with casein (CD). PER value of rats fed with DS was significantly lower (p < 0.05) than casein. In the nitrogen balance study, true nitrogen absorption (TNA) and nitrogen balance (NB) of BS group was significantly higher (p < 0.05) than DS group. However, apparent digestibility (AD), true digestibility (TD) and biological value (BV) for both diets was not significantly different. This study showed that the protein quality of dried Roselle seeds was similar to the Roselle seeds boiled at 100oC for 30 minutes.
Food-borne diseases have always been a major concern to the consumers, food safety authorities and food industries. Hylocereus spp or Pitaya peels are normally treated as wastes and will be discarded during processing. In this study, the antibacterial activity of ethanol, chloroform and hexane extracts from Hylocereus polyrhizus (red flesh pitaya) and Hylocereus undatus (white flesh pitaya) peels against nine pathogens was evaluated using disc diffusion method and broth micro-dilution method. Result from disc diffusion method showed that chloroform extracts from H. polyrhizus and H. undatus peel were found to exhibit good antibacterial activity where almost all the pathogens studied were successfully inhibited. Result of the minimum inhibitory concentration (MIC) showed that all extracts inhibit the growth of bacteria in the range of 1.25-10.00 mg/mL for all bacteria while their minimum bacteriacidal concentrations (MBC) indicated double of the MICs concentration except for B. cereus, L. monocytogenes and C. jejuni. Even though there is no clear trend indicating which bacteria were sensitive most to the extract, it can be concluded that chloroform extract of both H. polyrhizusand H. undatus peel showed the most potent antibacterial activity. Thus, these findings could be used further to understand the antibacterial property of the peel of pitaya fruits.
Unprocessed ‘budu’ is a mixture of anchovies and salt that has been fermented for a period of time, and has not been heat-treated nor formulated with additional ingredients. This study analyzed Malaysian
unprocessed ‘budu’ from 12 producers for microbiological, salt, protein, histamine and 3-MCPD contents.
The results demonstrated that Malaysian unprocessed ‘budu’ were free from pathogenic Coliform, E. coli,
V. parahaemolyticus and V. cholerae contaminations. Carcinogenic 3-MCPD was below detection level of 2 ppb for all 12 samples tested. However, 58% of the unprocessed ‘budu’ had histamine content greater than the hazardous levels of 50 mg/100 g sample.
Antibacterial effect of modified sago starch-alginate edible film incorporating lemongrass oil at various concentrations was studied. Edible films were prepared from a mixture of modified sago starch and alginate. Lemongrass oil (0.1 - 0.4%, v/w) and glycerol (0 and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antibacterial activity against food pathogenic bacteria such as Escherichia coli O157:H7, Salmonella Enteritidis and Staphylococcus aureus. The edible film exhibited antibacterial activity against Escherichia coli O157:H7 and Salmonella Enteritidis by using agar diffusion assay method. For films tested against Escherichia coli O157:H7, the zone of inhibition increased significantly (p < 0.05) with addition of lemongrass oil at all levels both in the presence and absence of glycerol. The films also significantly (p < 0.05) inhibited the growth of Salmonella enteritidis only with 0.4% lemongrass oil (in the presence and absence of glycerol). However, the films containing lemongrass oil did not show any inhibition effect on Staphylococcus aureus.
Maintaining the quality of bakery products is vital for consumers’ health and preference. Since bakery products are intermediate-moisture foods, spoilage by moulds is among the major causes of shelf life reduction. In the present work, the effects of substituting banana purée with banana powder to extend the shelf life of banana cakes were investigated over a ten-day storage period. Three types of banana cake were made using banana purée (control), laboratory-formulated powder (LP), and commercial powder (CP). Results indicated a significant difference in moisture contents and water activities between all treatments in which LP and CP exhibited mould growth at day 9 compared to day 5 in control. For fungal load, LP yielded the lowest CFU by the end of storage period. Although significant differences in texture and appearance were noted between all treatments, untrained sensory panellists scored LP as acceptable. Further works are therefore warranted to assess LP’s commercialisation potentials.
An extensive amount of research has reported on the use of ultrafiltration (UF) membrane,
particularly in the improvement of membrane performance efficiency on cow’s milk. However,
a very limited number of researches reported on using UF for producing low-lactose goat’s
milk due to inherently low lactose. Nonetheless, goat’s milk is still not suitable to be consumed
in a large amount by people who are lactose intolerant, especially among Asians, where
over 90% of the populations are suffering from lactose intolerance. Until today, fouling and
concentration polarization (CP) on membrane surface in cross-flow hollow fiber UF unit are
the major problems in the dairy industry. Discovery on how to overcome the problem is still
in a hot debate due to the nature’s complex composition in milk. One way to overcome this
problem is by evaluating the effects of processing parameters such as trans-membrane pressure
(TMP) and feed-flow rate on flux (J), lactose rejection (Ri), concentration factor (CF), and
accumulation rate (AR) during the fractionation of lactose. In terms of lactose fractionation for
5 KDa and 10 KDa UF membranes, the TMPs examined were 0.41, 0.55, and 0.69 bars, while
feed flow-rates examined were 0.18, 0.34, 0.54, and 0.74 L/min. 5 KDa membrane shows that
feed flow-rate and flux behave in a direct relationship, while an inverse relationship in 10 KDa
membrane. Both membranes showed that TMP 0.55 bar exhibit the best flux value without
reaching the limiting flux region, but with feed flow rate of 0.74 L/min in 5 KDa, while 0.18
L/min in 10 KDa membrane. Lactose rejection percentage (%Ri) is the lowest with 77.71% in
5 KDa membrane while 66.28% in 10 KDa membrane. This can be summarized that the best
parameters for 5 KDa membrane is at TMP 0.55 bar with feed flow-rate of 0.74 L/min, while
for 10 KDa membrane is at TMP 0.55 bar with feed flow-rate of 0.18 L/min. Due to higher flux
value and lowest lactose rejection obtained from low feed flow-rate, 10 KDa UF membrane
size was chosen over 5 KDa. As a conclusion, a high degree of lactose removal from goat’s
milk could be achieved by 10 KDa UF membrane in a cross-flow hollow fiber system, which
proved that different outcomes between 5 KDa and 10 KDa membranes and feed flow-rate
required is closely associated to UF pore size and molecular weight of feed solute particles.
A study was done on the feasibility of inulin, a fructooligosaccharides with the health benefits of prebiotic, as partial sugar replacer in “kaya” by investigating the effects of different substitution levels (0%; control, 10%, 30% and 50%) on the sensory properties. The samples were investigated by 10 descriptive panelists for colour, sweetness, smoothness, firmness, adhesiveness and spreadability attributes before further evaluated by 100 consumers for acceptance levels. Consistent with the descriptive panel, the evaluation by the consumers showed formulated samples at 10% and 30% were comparable to the commercial “kaya” being no significant difference (p>0.05) found in acceptability scores. 50% substitution received lower acceptability scores and was significantly different (p
Bacterial spores have special significance in foods because they are much more resistant to physical and chemical antimicrobial treatment. Nowadays, there is interest in using natural products such as plant extract for food preservation. In this study, 26 of tropical medicinal plants and spices were screened for their sporicidal activity against the spores of Bacillus cereus. The spores of B. cereus was harvested after incubation at 30°C for 1 week and treated with various plant extracts using the method of Standard Operating Procedure for the AOAC (Association of Official Analytical Chemists) Sporicidal Activity. Glutaraldehyde was used as a positive control. Among them, Indonesian bay leaf (Eugenia polyantha Wight) inactivated more than 3 log of spores/ml of B. cereus (99.99%) at the concentration of 1% and completely killed B. cereus spores at concentration of 2.5%. These results suggest that Indonesian bay leaf extract has strong sporicidal activity against spores of B. cereus.
The production of bioprotein by coconut dregs is found to be a novel and cheaper carbon source.
Media optimization for bioprotein production from coconut dregs through solid state fermentation has been developed as a one of the approaches to increase the protein production. The utilization of these coconut dregs provides as alternative substrates and also helps in solving waste disposal problems. Among the seven media components, only NH4NO3, MgSO4.7H2O and CuSO4.5H2O were found to be significantly affecting the bioprotein production.
Extraction of collagen from muscles of cultured catfish (Clarias gariepinus × C. macrocephalus) with the aid of pepsin digestion was investigated using a statistical tool. Fractional factorial design (FFD) was applied to evaluate the effects of eight process parameters: acetic acid concentration, acid extraction time, acid extraction temperature, acetic acid to muscles ratio, NaOH concentration, NaOH to muscles ratio, NaOH treatment time, and stirring speed. Contribution of every parameter in influencing the extraction efficiency was evaluated and factors that significantly affected the extraction were elucidated by employing experimental design and analysis of variance in FFD. The result of first order factorial design showed that acetic acid concentration, acid extraction time, acid to muscles ratio, and stirring speed had significant effect (P < 0.05) to the yield of pepsin soluble collagen (PSC) obtained at the end of the experiment. Effects of these process factors on the efficiency of collagen extraction were investigated, and are discussed in detail. Optimum conditions were found at 0.5 M acetic acid, 16 hr extraction period, solvent to muscles ratio at 25 ml/g, and stirring speed of 400 rpm, resulting in yield of PSC as high as 211.49 ± 15.51 mg/g.
This study was conducted to evaluate antimicrobial properties of ethanolic extracts of the leaves of Nephelium lappaceum, Curcuma longa, Cinnamomun cassia, Durio zibethinus, Vitex trifolia, Amaranthus tricolor, Syzygium samarangense and Manihot esculenta. Antibacterial properties of the extracts were studied against fifteen strains of different gram positive and gram negative pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Vibrio para, and Escherichia coli using the agar disk diffusion method. Among the tested extracts, only Amaranthus tricolor exhibited specific inhibition of one of the tested bacteria; Bacillus cereus. Using the microdilution method, its minimum inhibitory concentration (MIC) value was determined to be 20 mg/mL.
Piper nigrum, commonly known as black pepper, is one of the most important spice crops
with high demand by the world market. However, diseases like foot rot and stem blight
cause by Phytophthora capsici have become the important production constraints in black
pepper industry. The frequent application of toxic fungicides to counter the diseases in pepper
plantations has raised certain environmental issues. In order to mitigate the use of fungicides,
biological approach to control P. capsici has been suggested. In this study, endophytic bacteria
were isolated from six P. nigrum roots and screened for in vitro antagonistic activity against P.
capsici through dual culture, mycelial growth, spore germination and double plate assay. The
antagonism testing involved the secretion of volatile and diffusible bioactive compounds by
the endophytic bacteria. Out of 19 isolates tested, two isolates DB(2)7 and SB(2)6 produced
volatile bioactive compounds and these two isolates showed highest antagonism against P.
capsici mycelia with the percentage of inhibition up to 47.63% and 43.33%, respectively.
Diffusible compounds from isolates DB(2)7, DB(2)9 and SB(2)6 produced clear zones in spore
germination test with radii measurements of 10.0-17.0 mm. Three isolates with promising
antifungal activity were further characterised through 16S rDNA sequencing. The analysis
of their sequences via National Center for Biotechnology Information (NCBI) suggests close
identity towards Enterobacter cancerogenus, Enterobacter cloacae and Enterobacter asburiae.
This research study demonstrated that these endophytic bacteria isolates are potentially to be
used as biocontrol agent in pepper cultivation.
Edible medicinal plants are often used in the treatment of various ailments and spice in traditional food preparation. In this study, 45 of tropical edible medicinal plants extracts from Indonesia, Malaysia, and Thailand were screened for their antimicrobial activity against five standard microorganisms for food preservative namely Aspergillus niger, Candida albicans, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The methanol extracts of Piper nigrum L. seed, Piper cubeba L. seed, and the root of Ligusticum acutilobum Siebold and Zucc. showed antimicrobial activity against five species of standard microorganisms. Among them, P. cubeba L. extract demonstrated the most susceptible against all tested microorganisms. Minimal inhibitory concentration (MIC) and minimal bactericidal or fungicidal concentration (MBC or MFC) were performed by the broth microdilution techniques as described by the Clinical and Laboratory Standard Institute. MIC values of P. cubeba L. extract to A. niger, C. albicans, E. coli, P. aeruginosa and S. aureus were 12.8, 1.6, 3.2, 6.4, and 1.6 mg/ml, respectively. P. cubeba extract killed A. niger, C. albicans, E. coli, P. aeruginosa and S. aureus with MBC values of 25.6, 3.2, 6.4, 12.8, and 3.2 mg/ml, respectively. The potent antimicrobial activity of P. cubeba L. extract may support its use for natural food preservative.
Characterization and quantification of carotenoid compound is complicated, costly and timeconsuming. The accuracy and reliability of the data depend solely on the standard and to High Performance Liquid Chromatography (HPLC) analysis but the major constraint is to acquire and to maintain the pure standards. Carotenoid standards are commercially available but they are expensive and are prone to isomerization and oxidation. Thus, the purpose of this study is to establish an analytical method for isolating β-carotene by using open column chromatography (OCC) from pumpkin (Cucurbita moschata) to be used as one of the carotenoid standards for determination of total and individual carotenoid. Pumpkin with orange flesh has been chosen due to the non-seasonal nature and its availability all year-round. This study demonstrated that the purity of β-carotene standard; determined by HPLC was ranged from 92.21 to 97.95%. The standard curves with five different concentrations of β-carotene extract from pumpkins in triplicate were constructed by plotting the peak area against the concentration. The coefficient of correlation was 0.9936. Therefore, this study established that pumpkin can be a reliable source of beta-carotene standard as it is cheap and commonly available throughout the year.
Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.
The “fate” of salt in yellow alkaline noodles was followed by measuring the salt release from
yellow alkaline noodles during cooking and mastication. Three types of yellow alkaline noodles
were produced; yellow alkaline noodles with salt at 0 (YAN0), 5 (YAN5), and 10% (YAN10)
of the flour weight. Salt release during cooking was influenced by the cooking time and salt
content of yellow alkaline noodles. Extended cooking resulted in higher loss and low salt
yellow alkaline noodles showed a higher percentage loss than those with high salt. Textural,
mechanical and structural breakdown properties were in the order: YAN10 > YAN5 > YAN0,
with YAN10 being the hardest, chewiest, firmest, and has the highest strength and structural
integrity. These findings support that low salt content in yellow alkaline noodles and a more
extensive chewing resulted in higher percentage of salt release than high salt yellow alkaline
noodles that are chewed less extensively.
The interest in dietary antioxidants which are mainly found in fruits, has prompted research in
the field of commercial high antioxidant juice for healthy purposes. Fruits also are rich with antioxidants that help in reducing of degenerative diseases such as cancer, arthritis, cardiovascular
disease and inflammation. Based on the health claims from the natural antioxidants, a new healthy juice called Mixed Fruit Juice (MFJ) has been developed by using three combinations of local fruits (soursop, mango and kasturi lime). In order to promote the commercial use of this product, the safety evaluation is needed to be carried out. The 28-days repeated toxicity test has been conducted in female and male rats for pre-clinical safety assessment prior to human study. There was no mortality observed when varying doses of the MFJ (5, 10 and 20%) administered to all rats. Hematological analysis showed no significant differences in most parameters examined. There were no significant changes observed in the liver and kidney functions tests of all treated-rats as compared to control normal rats. Furthermore, lipid profiles and blood glucose level were also within the normal range as noted in control rats. The present data demonstrate that the supplementation of MFJ did not produce adverse effects on the body system of experimental rats. This is the first documented report on the safety assessment of
MFJ in rats.