This study was designed to elucidate the effects of osmotic dehydration of pumpkin slice prior to hot-air drying. Response Surface Methodology (RSM) with Central Composite Design was used to investigate the influence of three variables, namely sucrose concentration (30-60˚Brix), immersion temperature (35-65˚C) and immersion time (90-120 min). These factors increased the solid gains and decreased the water activity (aw) of the sample; while the temperature and sucrose solution concentration increased the water loss (p
Two functional food oils, namely extra virgin olive oil (EVOO) and virgin coconut oil (VCO) have been analyzed simultaneously using Fourier transform infrared (FTIR) spectroscopy. The performance of multivariate calibration of principle component regression (PCR) and partial least square regression (PLSR) was evaluated in order to give the best prediction model for such determination. FTIR spectra were treated with several treatments including mean centering (MC), derivatization, and standard normal variate (SNV) at the combined frequency regions of 3050 – 3000, 1660 – 1650, and 1200 – 900 cm-1. Based on its capability to give the highest values of coefficient of correlation (R) for the relationship between actual value of EVOO/VCO and FTIR predicted value together with the lowest values of root mean square error of calibration (RMSEC), PLSR with mean centered-first derivative spectra was chosen for simultaneous determination of EVOO and VCO. It can be concluded that FTIR spectroscopy combined with multivariate calibration of PLSR was successfully applied to simultaneously quantify EVOO and VCO with acceptable parameters.
Centella asiatica L. is traditionally used as a medicinal herbs and alternative medicine in treating numerous kinds of diseases. The use of Centella in food and beverages has increased over the years. Its potential antioxidant and neuroprotective activity has been widely claimed in many reports and basically is very much related to its properties and mechanism of action of the plant’s bioactive constituents namely the asiaticoside, asiatic acid, madecassoside and madecassic acid. As such, this review will cover the biological activity of the plant’s active constituents in relation to its food and beverage applications. The plant cultivation and biotechnological approaches to improve the production of desired bioactive constituents by cultured cells will also be reviewed. In addition, the range of chemical compositions found in Centella and safety aspects are also included.
Protein Efficiency Ratio (PER) is the most widely used method for determining protein quality. The studies involved a few category of products as raw materials namely poultry products, beef burger products, fish and fish products, soy products and palm kernel cake in animal diet preparation were compiled to compare the data. Data from the proximate analysis showed that protein content in soy protein isolate (SPI) was the highest (95.00%) followed by meat such as mackerel fish (89.09%) and beef (88.60%). Results from feed consumption and total protein consumed showed that the rats fed with mechanically deboned poultry meat (MDPM) products (excluding broiler back) consumed more feed, ranging from 469.2g to 422.3g during the study while the lowest total feed consumed (157.7g) was recorded in the rat fed a diet of fermented palm kernel cake (fPKC). The total protein consumed by rat for diets of fish and fish products such as canned sardine was 62.36g, mackerel 61.76g and anchovy at 58.91g, followed by MDPM products. Tempeh (14.72g) and fPKC diet (16.3g) were among the lowest total protein consumed by the rats. Growth and PER data for rats fed a diet of canned sardine, anchovy and mackerel, as well as mechanically deboned turkey meat (MDTM) and mechanically deboned chicken meat (MDCM) had higher mean body weight (154.80g, 145.20g, 144.81g, 148.7g and 142.5g respectively) compared to rats fed with plant protein diet such as SPI, tempeh and PKC (34.79g, 16.34g and 16.60g respectively) whereas rats fed diets containing fPKC had a mean body weight loss of 24.4g. MDPM showed higher PER value (ranging from 3.01 to 3.34) compared to hamburger group, pure beef and fish group. Tempeh and SPI had lower PER of 1.02 and 1.52 respectively while the lowest PER of 0.50 and -1.50 were shown in PKC and fPKC. The highest digestibility was shown in mackerel (96.99%), followed by canned sardine (96.88%), tempeh (91.41%), meat (90.79%) and pure beef burger (90.04%) while digestibility of PKC and fPKC were much lower (45.70% and 22.60%). Lipid profile of rats fed with palm based fat beef burger showed that palm fat(PF) and red PF did not affect the total cholestrol concentration but resulted in higher high density lipoprotein (HDL)- cholesterol concentration in their blood serum. In summary, the utilization of PF and red PF in beef burger increased the HDL-cholesterol and has no effect on the concentration of total cholesterol in rat blood serum.
Five different brands of Malaysian commercial beef frankfurters were analyzed for quality characteristics. The proximate contents showed significant differences among the samples. The range of moisture content was 63.0-73.9%; the protein content was 10.63-16.43% while the fat content was 1.71-12.22%. The lightness value (L*) of the uncooked frankfurters, which was in the range of 47.02-52.28, was significantly different among the samples. The lightness of the cooked frankfurters, showed a decrease in all the samples compared to the uncooked samples. No significant differences were observed for the folding test; where all samples showed no cracks after they were folded in half. However, significant differences were observed for the texture analysis. The hardness, cohesiveness, chewiness, springiness, gumminess and shear force ranged between 4.59-10.30 kg, 0.26-0.35, 16.15-51.72 kgmm, 12.73-14.79 mm, 1.17-3.49 kg and 1.67-7.08 kg respectively. The results of the study showed that Malaysian commercial beef frankfurters were significantly different in their physicochemical properties.
Listeria monocytogenes is a gram positive, facultative intracellular pathogen with the capacity to cause
food poisoning outbreaks as well as severe illness in vulnerable human population groups. It can cause a rare but serious disease called listeriosis with high fatality rates (20–30%) compared with other foodborne microbial pathogens. Although Listeria monocytogenes is infective to all human population groups, it is more likely to cause severe problems among pregnant women, immunocompromised individuals, the elderly and neonates. There are a variety of phenotyphic and genotyphic methods for the detection of Listeria monocytogenes in foods. Recent technological advances have increased the ability of scientists to detect Listeria monocytogenes. The purpose of this review is to discuss molecular characteristics of the Listeria monocytogenes pathogen, standard detection methods of this pathogen in foods based on culture methods, confirmation of species and subtyping based on phenotypic and genotyphic methods.
Phytates have been considered as a threat in human diet due to its antinutrients behaviour which
known as strong chelators of divalent minerals such as Ca2+, Mg2+, Zn2+ and Fe2+. Phytic acid has a potential for binding positively charged proteins, amino acids, and/or multivalent cations or minerals in foods. The resulting complexes are insoluble, difficult for humans to hydrolyze during digestion, and thus, typically are nutritionally less available for absorption. The reduction of this phytates can be achieved through both enzymatic and nonenzymatic removal. Enzymatic degradation includes addition of either isolated form of wild-type or recombinant exogenous phytate-degrading enzymes microorganisms in the food matrix. Non-enzymatic hydrolysis of phytate occurred in the final food during food processing or physical separation of phytate-rich parts of the plants seed. The application of phytase with respect to breadmaking process, probiotics, animal feed supplement and transgenic crops are emphasised in this paper.
Synthetic antioxidants are added to food in the powdered form to preserve it. However these compounds posed serious health concern since they have been associated with causing cancer. Thus using fresh herbs with antioxidant activities would be good alternative. The objectives of this study were to evaluate and compare the total phenolic contents and antioxidant activities of both powdered and fresh forms of turmeric leaf, pandan leaf and torch ginger flower. Total phenolic content (TPC) was assayed based on the redox reaction between Folin-Ciocalteu with phenolics in the sample extracts. Antioxidant activity (AA) was assayed using the ß-carotene linoleate model system and the percentage of antioxidant activity was calculated from the values of degradation rate. Scavenging activity (SA) was assayed using the DPPH radical scavenging model system whereby EC50 value was determined from the plotted graph of scavenging activity against the concentration of sample extracts. Analyses revealed that powdered forms of turmeric leaf, pandan leaf and torch ginger flower had higher TPC (2013.09 ± 5.13, 1784.25 ± 7.59 and 1937.42 ± 6.61 mg GAE/100g, respectively) than their respective fresh forms (348.75 ± 1.26, 356.42 ± 1.32 and 211.59 ± 6.29 mg GAE/100g, respectively). Similarly, powdered forms of turmeric leaf, pandan leaf and torch ginger flower possessed better AA (64.31 ± 0.99, 65.09 ± 0.74 and 11.80 ± 0.40 %, respectively) than their respective fresh forms (24.93 ± 0.71, 16.91 ± 0.70 and 1.45 ± 0.10 %, respectively). Powdered forms of turmeric leaf, pandan leaf and torch ginger flower were also better radical scavenger as compared to their respective fresh forms. In conclusion, all samples in their powdered forms have high total phenolic contents, antioxidant and scavenging activities than their respective fresh forms.
Fried and baked banana-based snacks are popular in South East Asia and banana chip is popular in
other countries, such as India, Indonesia, China, African countries, etc; these snacks may contain acrylamide in concentration which may be of concern due to its toxicity. This study was carried out to determine acrylamide concentration in popular banana based snacks in Malaysia using a modified method of gas chromatographymass spectrometry. The limit of detection and limit of quantitation of the modified method are 5 and 15 μg/kg, respectively. Acrylamide concentration of five types of Malaysian popular fried and baked banana based snacks from different local markets ranged from 74.0 to 7468.8 μg/ kg for banana fritter (pisang goreng), 28.9 to 243.7μg/kg for banana chips (kerepek pisang), 160.7 to 500.4 μg/kg for sweet banana chips (kerepek pisang manis), not detected to 154.4 μg/kg for banana cake (kek pisang) and 31.7 to 609.1 μg/kg for banana balls (cekodok pisang). Analysis of variance showed a significant difference (P
The whole plant extract of plant Sceletium tortuosum, plant native to South Africa, has been known
traditionally to have mood enhancing and stimulant properties. These properties have been confirmed before by proving serotonin-uptake inhibition activity. A further confirmation by using CB1 receptor binding assay has been performed in this study. The unfermented alkaloid extract was proved to posses a higher activity to bind CB1 receptor compared to that of the fermented one. GC-MS analysis confirmed that unfermented alkoloid extract contain more alkaloids than the fermented one. The ethanol extract was also more active than the fermented one, suggesting that non-alkaloid compounds in this extract could posses this activity. An additional test to check wether this extract can improve cognitive function and memory was performed by acetylcholinesterase inhibitory assay. Both fermented and unfermented alkaloid extracts could inhibit acetylcholinesterase with IC50 being 0.303 mg/ml and 0.330 mg/ml, respectively. However, the major alkaloid in the extract, mesembrine, did not show inhibition of the enzyme. A TLC based test proved that other alkaloids in the extract were responsible to the activity.
The aim of this study is to compare antioxidant level and activities (i.e. primary and secondary) in pulps and peels of two species of dragon fruits, Hylocereus undatus (white dragon fruit) and Hylocereus
polyrhizus (red dragon fruit). Total phenolic content (TPC) assay demonstrated that peels of both Hylocereus species contained higher phenolic content than the pulps. The phenolic content in peels of H. undatus was higher than H. polyrhizus, but the phenolic content in pulps of H. undatus was much lower than H. polyrhizus. 2, 2, diphenyl-1-picrylhydrazyl (DPPH) assay showed that radical scavenging activities of peels for both species were higher than the pulps. For ferrous ion chelating (FIC) assay, peels and pulps of both Hylocereus species showed moderate metal ion chelating effect as compared to EDTA. Overall, the results suggested that the TPC showed good relationship with the primary antioxidant activities for general comparison between the peels and the pulps.
This study investigates the effect of flaxseed oil towards physicochemical and sensory properties of reduced fat ice creams and its stability in ice-creams upon storage. Three formulations, (F1, F2, F3) were developed by substituting milk fat with flaxseed oil at levels of 2.5%, 5.0% and 7.5%, (w/w) respectively. Samples were subjected to sensory evaluation and analyses such as meltdown, titratable acidity, pH, total solids, protein and fatty acids composition. Incorporation of flaxseed oil into ice-cream showed no effects on physicochemical properties of the ice-creams. However, it increased the colour of ice-cream towards yellowness, decreased the sweetness, smoothness and creaminess. Flaxseed oil incorporation also slightly (P < 0.05) decreased the acceptance level of aroma, flavour, texture and overall acceptability of formulated icecreams. The most acceptable level of flaxseed oil substitution is at 2.5 %. Gas chromatography analysis showed that fatty acids slightly decreased upon storage.
This study was conducted to determine radical scavenging activity and vitamin antioxidant composition in red pitaya from organic plantation. For antioxidant vitamins analysis, a reverse-phase high performance liquid chromatography was used and radical scavenging activity of methanolic and water extract were determined using 1,1-diphenyl-2-pircrylhydrazyl assay. Results for radical scavenging activity, red pitaya methanolic extract achieved the highest percentage 70.13% compared with water extract (47.13%). Antioxidant vitamins composition in red pitaya showed that the concentration of vitamin A is 120.13 ± 0.69 μg/100 g freeze-dried sample, vitamin C is 540.27 ± 0.59 μg/100 g fresh samples and vitamin E is 105.67 ± 0.56 μg/100 g freeze-dried samples. This shows that red pitaya may become an alternative and potential source of natural antioxidant.
Hepatitis A virus infection occurs globally and is causing a public health concern, primarily in developing countries due to its persistent circulation in the environment. The improved sanitary condition and increase in awareness of personal hygiene have led to the marked reduction of HAV prevalence in industrialized countries during childhood and to a shift of the infection towards adulthood. HAV is an environmentally stable, positive single stranded RNA virus that is primarily transmitted by the fecal-oral route, person to person contact or ingestion of contaminated food and drink. One of the main causes leading to HAV infection is epidemiologically linked to the consumption of raw or undercooked shellfish particularly oysters and clams. Due to their filter-feeding style, these shellfishes readily concentrate viruses from the surrounding water containing municipal sewage, and as a consequence pose a health threat to consumers. Therefore, development of detection techniques possessing the requisite sensitivity and specificity for the practical routine monitoring purposes is of great importance necessary for the protection of shellfish-consuming public. Nucleic acid based method such as reverse transcription PCR has emerged as the popular method of choice in view of its rapidity, accuracy and
sensitivity in contrary of the time-consuming conventional cell culture and hybridization techniques. However, detection of hepatitis A virus is firstly hampered by the non-cytophatic effect of wild type HAV strain, secondly, the low concentration of viral genome present in the environmental sample which requires effective isolation and concentration of virions and lastly the labor-extensive purification and thorough removal of the abundance of the PCR inhibitors which will unfavorably reduce the efficiency of PCR detection.
Application of surface plasmon resonance (SPR) biosensor in detection of genetically modified organism (GMO) is demonstrated. A total of four biotinylated probes namely Tnosb, P35Sb, LECb and TSQb were successfully immobilized onto the SA chip. Results analysis indicated that the SPR system with the sensor chip immobilized with the Tnosb, P35Sb, LECb and TSQb biotinylated probes potentially detect complementary standard fragments as low as 1 nM. Biospecific interaction analysis (BIA), employing surface plasmon resonance (SPR) and biosensor technologies provide easy, rapid and automatable approach in detection of GMOs. Short assay times, label free DNA hybridization reaction and no toxic compounds are required, i.e. ethidium bromide, and the reusability of the sensor surface are some of the factors that contribute to the general advantages of the surface plasmon resonance (SPR) biosensor system in detection of GMOs.
Local wood charcoal was used as the main component of the electrodes of an air-cathode microbial
fuel cell (air-cathode MFC) in current study. The air cathode was build with finely milled charcoal powder and cement plaster as binder; while anode was made up of a packed bed of charcoal granules. Mangrove estuary brackish water was inoculated in the anodic chamber as the fuel and a source of exoelectrogens. The constructed fuel cell was monitored by measuring the potential over time. The MFC generated a stable power density at 33mW/m2 (0.5V) under a load of 200Ω after 72 hours of operation. An open circuit voltage (OCV) of 0.7mV was obtained after 15 hours operating under open circuit. The result of power generation by the constructed fuel cell indicating that wood charcoal could be used as electrode in an MFC and that brackish water contained potential exoelectrogens. However, further investigation and modification is required to increase the performance of the fuel cell.
The activities of lipase produced by five lipases-producing thermophilic bacteria strains (SY1, SY5, SY6, SY7 and SY9) isolated from Selayang Hot Spring in the western part of Peninsular Malaysia were analyzed and compared. SY7 and SY9 had considerably higher lipolytic activities than those of SY1, SY5 and SY6. Thermostabilities of lipase produced by all strains were determined after heating at 80°C for 30 minutes. Strain SY7 retained the highest lipolytic activity of 77%, while others had infinitesimally low thermostability (retaining less than 34% of their original activity) at the same temperature and time. SY7 was chosen for further characterization because it showed exceptionally high lipase activity and thermostability. It was identified as belonging to Bacillus species by the conventional Gram-staining technique, Biochemical tests and Biolog Microstation system. By using 16S rRNA gene sequencing, strain SY7 generated the same expected PCR product with molecular weight of 1500 base pair. It displayed 98% sequence similarity to Bacillus cereus strain J-1 16S rRNA gene partial sequence with accession number: AY305275 and has been deposited in the database of Genbank.
Lycopene and total phenolics of pink guava puree industry by-products (refiner, siever and decanter)
were evaluated after steam blanching at selected temperatures and times. Lycopene content was in the order of decanter > siever > refiner (7.3, 6.3 and 1.5 mg/100 g, respectively), and the content of total phenolics was in the order of refiner > siever > decanter (4434.1, 2881.3 and 1529.3 mg GAE/100 g, respectively). Regression coefficients for temperatures (x1) and times (x2) from multiple linear regression models of siever and decanter showed significant (p
Processed meat products, such as burgers, sausages, meatballs, salami and nuggets are currently popular with urban consumers. However, in general, they are high in cholesterol, total lipid and saturated fatty acids. Four beef burger formulations were prepared, each containing 15% fat from either beef fat (control), palm fat (PF), red PF or a blend of PF and red PF at a ratio of 1:1 at 15% fat. A rat assay was carried out to determine lipid profile, apparent digestibility (AD) and protein efficiency ratio (PER) of rats fed with beef burger diets containing palm based fats. Treatment with PF and red PF beef burger diets did not affect the total cholesterol concentration but resulted in higher HDL-cholesterol concentration in their blood serum. The rats fed with dried burger diets containing PF and red PF had higher AD value (90.0% and 89.3%, respectively) and was not significantly different (P < 0.05) compared to the group fed with dried burger containing beef fat (90.7) over the 10 days experimental diet period. PER values of all treatments except for casein were not significantly different (P < 0.05). There was also no difference (P < 0.05) in food intake and body weight gain between all rats fed with dried burger containing different types of palm based fats. In summary, the utilization of PF and red PF in beef burger increased the HDLcholesterol and had no effect on the concentration of total cholesterol in rat blood serum. Addition of palm based fats into beef burgers did not change AD and PER.
Salmonella enterica is one of the major causes of bacterial foodborne infection. The aims of this study were to determine the antibiotic resistance and the genetic diversity of Salmonella enterica isolated from street foods and clinical samples and to understand the correlation between the prevalence of serovars and genotypes with their source (street food and clinical samples) and geographic origin (Negeri Sembilan, Malacca and Selangor in Peninsular Malaysia). The enterobacterial repetitive intergenic consensus (ERIC) PCR analysis distinguished the Salmonella isolates into 19 ERIC types, with one untypable isolate. Dendrograms were specifically constructed for the S. Biafra and S. Typhi isolates. Identical or very similar ERIC types among the S. Biafra isolates from street food samples indicate transmission of the S. Biafra among the street foods, as well as possible cross-contamination of the street foods. In addition, the identical or very similar ERIC types among the S. Typhi isolates from human samples examined suggest possible similarity in their source of infection. All the twenty four isolates were resistant to rifampin and none were resistant to cefuroxime. Most isolates displayed multiple resistances. Dendrogram of antibiotic resistances produced six clusters, with similarity levels between 18.8% and 100%. Generally, street food and clinical isolates tend to cluster apart. Dendrogram to cluster the antibiotic groups showed that they could be grouped according to classes based on mode of inhibition. The findings suggest that street food contaminated with drug-resistant Salmonella enterica can be an important factor in the continuous emergence of antibiotic resistant Salmonella enterica.