Konjac glucomannan (KGM) was treated with or without sonication and/or hydrochloric acid (HCl).
Hydrolysis effects on KGM were studied for properties such as degree of hydrolysis, fluidity, molecular mass, and creep properties. The degree of hydrolysis for sonicated KGM and acid treated KGM were not significantly different. However, the combination treatment of acid hydrolysis and sonication was found effective in yielding a smaller molecular weight fraction of KGM and solution with higher fluidity. From the creep analysis, KGM treated with combination treatment exhibited the highest compliance among samples tested. In general, ultrasound mediated acid hydrolysis was found to be a promising technique in degrading high molecular weight biopolymer. This could be attributed to a localized high temperature and high shear forces generated during cavitation that facilitated the endothermic acid hydrolysis.
The aim of this study is to determine the total phenolic content and primary antioxidant activity of methanolic and ethanolic extracts of four aromatic plants’ leaves namely knotweed (Polygonum minus), curry (Murraya koenigii), kaffir lime (Citrus hysrix) and fragrant screwpine (Pandanus odurus). Total phenolic content (TPC) assay using Folin-Ciocalteu method was used to assess the presence and level of phenolic compounds in each sample. The present study showed that both methanolic and ethanolic extracts of P. minus had the highest TPC and followed by M. koenigii, C. hystrix and P. odorus. Primary antioxidant activity in terms of free radical scavenging activities of both methanolic and ethanolic extracts was then measured by 2, 2, diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay. The lowest EC50 values based on the DPPH. radical scavenging activity were shown by P. minus extracts as compared to the other samples. For both ethanolic and methanolic extracts, the correlations between TPC and EC50 based on the DPPH. radical scavenging activity assay were negative and weak. Relatively, the present results suggest that of the four aromaticplants, P. minus and M. koenigii have shown potential as sources of natural antioxidants.
Keropok Lekor or frankfurter-like snack has long existed in Malaysia and has been sold in commercial retail shops as well as on the streets. The aims of this study were to analyze consumer’s perception and attitude towards keropok lekor and to determine consumer’s behavior on the product. Survey questionnaire was employed as a data collection tool. A total of 212 respondents from a university participated in this study. Results showed that more than 70% of the respondents chose to eat keropok lekor because of the taste. Half of the respondents chose black pepper as an innovative supplementary flavor of keropok lekor. This study also explores and analyses preliminary consumer behavior about keropok lekor such as satisfaction level, factors that drive consumption, product’s image from consumer perspectives and etc.
This study was conducted to determine the proximate composition and energetic value of selected marine fish and shellfish from the West Coast of Peninsular Malaysia. This study has included 20 species of fish (10 pelagic fish and 10 demersal fish) and 4 species of shellfish. For pelagic fish, Longtail shad (terubuk) was found to contain significantly lower moisture (59.31+0.00%), but significantly higher fat content (23.15+0.00%) compared to other fish species. For demersal fish, moisture and ash contents ranged between 74-82%, and 0.9-2.1%, respectively. Long-tailed butterfly ray contained the highest protein (22.22+1.24%) compared to other fish studied. The highest fat content of demersal fish was in Moonfish at 6.89+2.76%. For shellfish, prawn contained the highest protein (19.12+1.44%). The fat content of shellfish ranged between 1-2%. Oyster contained significantly higher carbohydrate at 6.45+0.00%, compared to other shellfish. Longtail shad contained the highest energetic value of 13.34 kJ g-1 of all samples. These values are useful references for consumers in order to choose fish and shellfish based on their nutritional contents.
Palm pressed fiber (PPF) is a by-product from oil extraction of oil palm fruits. It has unique characteristics resulting from the combination of palm mesocarp fiber, kernel shell and crushed kernel. The present study on different extraction methods for PPF indicated that conventional hexane cold extraction would be the more preferable method compared to soxhlet and reflux method due to the yield recovered (4.35%) and diacylglycerol (19.93% ± 0.07) obtained. Acylglycerol composition using cold extraction gave high Diaclyglycerol and Triacylglycerol (67.04% ± 0.05) with reasonable amount of Monoaclyglycerol / Free Fatty Acid (13.02% ± 0.02). Lauric acid which was not present in crude palm oil were found to be significant in PPF (5.89 to 9.09%), thus making this oil suitable for application in the food industry in products such as shortening and margarine.
This study aims to determine the combined effects of hydrolysis time, temperature, pH and ratio of enzyme to substrate on the degree of hydrolysis (DH) of silver catfish frame using Response Surface Methodology. The proximate compositions of silver catfish frame and silver catfish hydrolysate powder were determined as well. The effects of independent factors were described using a three-level factors Face Centered Central Composite design. The suggested hydrolysis conditions for obtaining the optimum DH using Alcalase® were – temperature of 55oC, hydrolysis time of 163 min, pH of substrate at 9.45 and an enzyme concentration of 2.0%. The generated model showed a quadratic fit with experimental data. Proximate analyses revealed that silver catfish frame contained 25.02% protein, 68.21% fat and 7.08% ash. While silver catfish frame hydrolysate powder contained 65.05% protein, 32.92% fat and 0.86% ash. The protein recovery in silver catfish frame hydrolysate was as high as 71.6%.
The effects of washing treatments and washing cycles on the thermal gelation properties and quality
characteristics of duckrimi (duck-base surimi-like material) were evaluated. Minced spent layer duck (4.5 mm orifice diameter) were washed by using either tap water, 0.1M NaCl, 0.5% NaHCO3 and 0.04M sodium phosphate in one, two or three washing cycles, respectively. Washing with 0.04M sodium phosphate in three washing cycles significantly increased (P
FTIR spectroscopy in combination with multivariate calibrations, i.e. partial least square (PLS) and principle component regression (PCR) was developed for quantitative analysis of cod liver oil (CLO) in binary mixture with corn oil (CO). The spectra of CLO, CO and their blends with certain concentrations were scanned using horizontal attenuated total reflectance (HATR) accessory at mid infrared (MIR) region of 4,000 – 650 cm-1. The optimal spectral treatments selected for calibration models were based on its ability to provide the highest values of coefficient of determination (R2) and the lowest values of root mean error of calibration (RMSEC). PLS was slightly well suited for quantitative analysis of CLO compared to PCR. FTIR spectroscopy in combination with multivariate calibration offers rapid, no excessive chemical reagent, and easy in operational to be applied for determination of CLO in binary mixture with other oils.
Most investigations on heavy metals content in fish were either conducted on single markets, ports, seaside markets or direct sampling from natural habitat, and there were very few studies done on fish samples from both wet markets and supermarkets. This paper presents the assessment outcome of Cd and Pb levels in commercial fish sold between wet markets and supermarkets in Klang Valley, Malaysia. In this study, the organs of four commercial fish species (Rastrellinger kanagurta, Epinephelus sexfasciatus, Lates calcarifer, and Decapterus maruadsi) sampled from different markets within the sampling area were assessed using dry ashing-acid digestion method and Flame AAS. Results obtained concluded that Cd and Pb in fishes sampled from supermarkets are generally higher compared to wet markets, while both metals content in the edible organs fall well within the permissible limits for human consumption when compared to the Fourteenth Schedule of the Malaysian Food Regulations 1985.
The ability to compare bovine and porcine skin gelatin based on their amino acid composition, polypeptides pattern, bloom strength, turbidity and foaming properties were investigated. Amino acid composition of both gelatin showed that the content of glycine, proline and arginine in porcine gelatin were higher than bovine gelatin. However, the polypeptides pattern between both gelatin is closely similar. The bloom strength of porcine gelatin was higher than bovine gelatin from pH 3 to pH 10. Both gelatin possessed highest bloom strength at pH 9. The lowest bloom strength of bovine gelatin was at pH 3 while porcine gelatin at pH 5. The highest turbidity of bovine gelatin obtained at pH 7 while porcine gelatin at pH 9. Foam expansion and foam stability of bovine gelatin were higher than porcine gelatin at all concentrations.
This research was to determine nutritional composition, essential and toxic elemental content, and major phenolic acid with antioxidant activity in Kadsura coccinea fruit. The results indicated that Kadsura coccinea fruit exhibited the high contents of total protein, total fat, ash and essential elements such as calcium (Ca), ferrum (Fe) and phosphorus (P). The levels of four common toxic elements, i.e. cadmium (Cd), mercury (Hg), arsenic (As) and lead (Pb), were lower than legal limits. By high-performance liquid chromatography (HPLC) analysis, gallic acid was identified as major phenolic acid in peel and pulp tissues. Its contents were no significant difference in both tissues. In comparison with two commercial antioxidants, the major phenolic acid extracted from Kadsura coccinea exhibited stronger 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and reducing power. Kadsura coccinea fruit is a good source of nutrition and natural antioxidant. It is worthwhile to popularize this exotic fruit around the world.
Several Norovirus cases due to consumption of green onions have been reported during recent years but reports on red onions are not found. Onions are one of the major tastes in Malaysian food which are sometimes consuming raw especially the green onion. Viral contamination in onions can occur due to planting condition and not properly prepared food. This situation can pose the human health risk. A method was developed to detect the Norovirus that might present on different type of onions. In this study, 60 samples were collected from local market. Elution by Tryptose Phosphate Glycine broth and concentration steps using negatively charge filter were applied to enhance the detection of virus in food due to low copies of virus on food surface. The viral RNA was extracted using Qiagen Rneasy Mini kit before further detection using One-step RT-PCR. The total incidence of Norovirus in green onion and red onion was 13.33% (4/30) and 3.33 % (1/30) respectively. This is the first report of the detection of Norovirus in red and green onions in Malaysia. Based on the results, it is concluded that this method is reliable to detect Norovirus on onions and vegetables surface and hence can be applied in the laboratories for routine or food borne outbreak investigation.
This study was performed to enumerate the total viable cell count of probiotic in five brands (A to E) of commercially cultured milk drinks that are available in the Malaysian market as well as to test their tolerance to various pH and bile concentrations by simulating the human gastrointestinal pH and bile concentration. The acid tolerance test was studied under pH 1.5 and 3.0 with 7.2 as control. The cell count for the acid tolerance test was obtained at an interval of 0, 1.5 and 3 hours respectively and was plated onto duplicate MRS agars to be incubated at 37°C for 48 hours. All cells recovered after 3 hours of pH treatment were selected for bile tolerance test in MRS broth containing bile concentrations of 0% (control), 0.3% and 2.0% and cell counts were recorded after 24 hours of incubation. The probiotic strains in products A, B, C & D met the suggested initial count of 106 CFU/ml with brand C recording the highest at 9.19 ± 0.14 log CFU/ml. Strains in product A, B & C showed good tolerance to pH 3.0 and 7.2 recording a count of >106 CFU/ml after 3 hours with a range of 6.60 – 9.04 log CFU/ml. The higher bile concentrations resulted in lower growth of strains in all the brands. Upon pH 1.5 treatment, only brand C recorded growth in all bile concentrations. After pH 3.0 treatment, all brands except brand E met the requirement of survival at 0.3% bile concentration. Results showed probiotics in product A, B & C met the initial count requirement, and exhibited good acid and bile tolerance therefore being a potentially good source of probiotic.
A total of 49 isolates of V. parahaemolyticus and 8 isolates of V. cholerae isolated from freshwater fish of patin (Pangasius hypopthalmus) and red tilapia (Oreochromis sp.) were purchased from different retail level in Selangor, Malaysia. All of the isolates showed a multiple resistances towards all 15 antibiotics tested. Some of the isolates show a high resistance to different antibiotics including bacitracin, vancomycin, tetracycline, furazididone, cephalothin and erythromycin. However, both species was susceptible towards imipenem. Overall antibiotics resistance patterns of all isolates were resistant from 2 to 14 resistance patterns with multiple antibiotic resistance (MAR) index ranging from 0.13 to 0.93 respectively. As the results obtained in the dendrogram produced from both species had indicates that these antibiotics were intensively used whether in the aquaculture farm through feeds during culture or at the hatchery production of seed. Thus, this study will provides an essential information of the MAR index and also the clustering analysis in order to determine the biosafety of Vibrio spp. in freshwater aquaculture fish sold at different retail level in Malaysia.
Malaysia, Biosafety Bill 2006 was approved by Parliament in July 2007, and labeling legislation will be implemented soon. In this study, duplex polymerase chain reaction (PCR) was carried out to detect
endogenous soybean lectin gene and exogenous cp4-epsps (5’-enolpyruvylshikimate-3-phospate synthase) gene simultaneously. Additionally, real-time PCR utilizing SYBR Green fluorescence dye were established for the quantitative analysis of Roundup Ready soybean (RRS), which is based on the two established calibration curve from cloned fragment of cp4-epsps gene and lectin gene respectively. Approximately, 39.5% (45/114) of the samples examined in this study contain RRS, animal feeds (31), processed food (13) and raw soybean (1). Additionally, 75.6% (34/45) of the positive samples were found contained RRS above 0.9%. The sensitive GMO quantitative approach described in this study enable the analysis of various samples and this will facilitate the labeling process.
This study reports on the microbiological quality of fresh and laboratory prepared pitaya fruit juice compared this with those collected from street vendors in the Penang island of Malaysia. Additionally, the microbial growth patterns were monitored during extended storage for up to 7 days at 2 different temperature ranges (at 10°C and 25±1°C). Results revealed the presence and increase in the incidence of bacteria, yeasts and moulds in all the juice samples (fresh and stored). Except for Klebsiella pneumoniae all the other foodborne pathogens screened in this study such as: Staphylococcus aureus, Salmonella sp. and generic Escherichia coli were absent. Our results highlights and stresses the need to employ proper hygienic conditions during harvesting and processing stages of pitaya fruit or their juices to improve the overall microbial quality to ensure adequate safety for consumers.
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.
The study investigated socio-demographic factors and product attributes affecting purchase decision of special rice by Malaysian consumer. The primary data were analyzed by using binary logit model.
Demographic factors and consumer preference for special rice (with reference to basmati rice) attributes were identified to affect purchasing behavior for special rice. Size of household, marital status, number of children, household income and gender of consumers are the main socio-demographic factors that significantly influence households’ choices of special rice for home consumption in the Klang Valley area. The findings also suggest that product attributes such as flavor and aroma, availability, brand name and quality also influence the frequent purchasing of Basmati rice among the Malaysian consumers. However price and easy preparation are not significant in influencing the frequent purchasing of Basmati rice since most consumers are aware that special rice such as Basmati is expensive and all rice has to be prepared in a usual way.
Efficacy of some Malaysian herbal aqueous extracts, BHA/BHT (synthetic antioxidants) and ascorbic acid in retarding oxidative rancidity was tested with cakes. The development of lipid oxidation products during 15 days at room temperature was evaluated by means of Peroxide Value (PV) and Thiobarbituric acidreactive substances (TBARS) value. The six formulations consists of control sample (cake without addition of antioxidant) (F1), cake added with curry leaves extract (F2), cake incorporated with kesum leaves extract (F3), cake added with tenggek burung leaves extract (F4), cake incorporated with ascorbic acid (F5) and cake added with BHA/BHT (F6). Formulation with the incorporation of tenggek burung leaves extract showed powerful oxidative stability effect compared to the formulations with othe plant extracts and control sample. However, cakes with BHA/BHT showed the strongest oxidative stability throughout the storage period. Therefore, it is suggested that tenggek burung leaves extract can be added into the food system for effectiveness as antioxidant to prolong the shelf life of the product.
Pineapple (Ananas comosus), Bromeliaceae family, is a fruit grows in tropical countries including Malaysia. This fruit has several pharmacological benefits due to the presence of high concentration of bromelain (cysteine proteases). Condition of elevated temperature will induce deformation of enzyme and result in loss of activity. Sulfhydryl groups in cysteine proteases are readily to be oxidized and might account for the denaturation of bromelain at elevated temperature. Polyphenol from ethanolic cashew leave extract could be complexed with bromelain to stabilize the enzymatic activity. In thermal stability test, the heat damage effect on bromelain was ten times reduced after complexing with cashew extract. The enzymatic activity of free bromelain decreased gradually from 25 o C to 95 o C. Complexed bromelain was stable in activity to heating up to 85 o C. Bromelainpolyphenol complex showed a good heat resistance. The result revealed that polyphenol could protect bromelain in pineapple juice from heat denaturation.