The present study compares water-soluble phenolic content (WPC) and antioxidant activities in Chinese long bean (Vigna unguiculata), bitter gourd (Momordica charantia), water convolvulus (Ipomoea aquatica) and broccoli (Brassica olearacea) prior to and after subjecting to boiling, microwaving and pressure cooking. The total antioxidant activity was increased in cooked water convolvulus, broccoli and bitter gourd, estimated based on the ferric reducing antioxidant power, the Trolox equivalent antioxidant capacity and 2,2-diphenyl-1-picryl-hydrazyl radical scavenging activity. Pressure cooking did not cause any significant decline in the antioxidant property. Boiling generally improved the overall antioxidant activity in all the vegetables. Correlation analysis suggests that WPC contributed to significant antioxidant activities in these vegetables. Thus, prudence in selecting an appropriate cooking method for different vegetables may improve or preserve their nutritional value.
Recycling waste cooking vegetable oils by reclaiming and using these oils as biodiesel feedstocks is one of the promising solutions to address global energy demands. However, producing these biodiesels poses a significant challenge because of their poor physicochemical properties due the high free fatty acid content and impurities present in the feedstock, which will reduce the biodiesel yields. Hence, this study implemented the following strategy in order to address this issue: (1) 70 vol% of waste cooking vegetable oil blended with 30 vol% of Calophyllum inophyllum oil named as WC70CI30 used to alter its properties, (2) a three-stage process (degumming, esterification, and transesterification) was conducted which reduces the free fatty acid content and presence of impurities, and (3) the transesterification process parameters (methanol/oil ratio, reaction temperature, reaction time, and catalyst concentration) were optimized using response surface methodology in order to increase the biodiesel conversion yield. The results show that the WC70CI30 biodiesel has favourable physicochemical properties, good cold flow properties, and high oxidation stability (22.4 h), which fulfil the fuel specifications stated in the ASTM D6751 and EN 14214 standards. It found that the WC70CI30 biodiesel has great potential as a diesel substitute without the need for antioxidants and pour point depressants.
A survey of lettuce sold in Penang markets showed them to be heavily contaminated with faecal coliforms and nearly half the samples were positive for Salmonella or Shigella. The use of night soil on these vegetables is a likely cause of gastroenteritis.
A simple and sensitive analytical method has been developed employing gas chromatography coupled with electron capture detector (GC-ECD), and validated for screening and quantification of 15 pesticide residues at trace levels in cabbage, broccoli, cauliflower, lettuce, celery, spinach, and mustard. The method consists of two steps, first, to determine the significance of each factor by Pareto chart followed by optimization of these significant factors using central composite design (CCD). Minitab statistical software was used for these multivariate experiments for the generation of 2(4-1) design and CCD matrices. The method evaluation was done by external standard calibration with linearity range between 0.5 and 3mg/kg, with correlation coefficient 0.99, limit of detection (LOD) ranges between 0.02 and 4.5ng/g, and limit of quantification (LOQ) ranges between 0.2 and 45ng/g. The average recovery was between 60% and 128%, with RSD 0.2-19.8%. The method was applied on real vegetable samples from Cameron Highlands.
Minimally processed fresh produce is one of the fastest growing segments of the food industry due to consumer demand for fresh, healthy, and convenient foods. However, mechanical operations of cutting and peeling induce the liberation of cellular contents at the site of wounding that can promote the growth of pathogenic and spoilage microorganisms. In addition, rates of tissue senescence can be enhanced resulting in reduced storage life of fresh-cut fruits and vegetables. Chlorine has been widely adopted in the disinfection and washing procedures of fresh-cut produce due to its low cost and efficacy against a broad spectrum of microorganisms. Continuous replenishment of chlorine in high organic wash water can promote the formation of carcinogenic compounds such as trihalomethanes, which threaten human and environmental health. Alternative green and innovative chemical and physical postharvest treatments such as ozone, electrolyzed water, hydrogen peroxide, ultraviolet radiation, high pressure processing, and ultrasound can achieve similar reduction of microorganisms as chlorine without the production of harmful compounds or compromising the quality of fresh-cut produce.
From April 1992 to September 1992, 280 samples of 10 different fresh vegetables, bought from four different market outlets in Kuala Lumpur were examined for the presence of Listeria spp. Most of the market produce were locally grown with the exception of carrots. The isolation procedure was based on the Food & Drug Administration method (modified) used for the detection of Listeria spp. Isolation media used were Listeria Selective medium and LiCl- phenylethanol-Moxalactam agars. The identification of isolates was by means of conventional biochemical tests and API Listeria identification system. Five out of the 280 samples showed Listeria contamination, Listeria monocytogenes was isolated in lettuce, sengkuang (Pachyrrhizus erosus) and selom Oenanthe javanica) and Listeria innocua was isolated from sengkuang (Pachyrrhizus erosus) and pegaga (Hydrocotyle asiatica).
Two hundred ten samples of selected vegetables (okra, pumpkin, tomato, potato, eggplant, spinach, and cabbage) from Faisalabad, Pakistan, were analyzed for the analysis of heavy metals: cadmium (Cd), lead (Pb), arsenic (As), and mercury (Hg). Inductively coupled plasma optical emission spectrometry was used for the analysis of heavy metals. The mean levels of Cd, Pb, As, and Hg were 0.24, 2.23, 0.58, and 7.98 mg/kg, respectively. The samples with Cd (27%), Pb (50%), and Hg (63%) exceeded the maximum residual levels set by the European Commission. The mean levels of heavy metals found in the current study are high and may pose significant health concerns for consumers. Furthermore, considerable attention should be paid to implement comprehensive monitoring and regulations.
The soil plant transfer coefficient or f factor of 14 C-carbofuran pesticide was studied in outdoor lysimeter experiment consisting of Brassica sp. vegetable crop, riverine alluvial clayey soil and Bungor series sandy loam soil. Soil transfer coefficients at 0-10 cm soil depth were 4.38 + 0.30, 5.76 + 1.04, 0.99 + 0.25 and 2.66 + 0.71; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 0-25 cm soil depth, soil plant transfer coefficients were 8.96 + 0.91, 10.40 + 2.63, 2.34 + 0.68 and 6.19 + 1.40; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 77 days after treatment (DAT), the soil plant transfer coefficient was significantly higher in riverine alluvial soil than Bungor soil whereas shoot and root growth was significantly higher in Bungor soil than in riverine alluvial soil. At both 0-10 cm Brassica sp. rooting depth and 0-25 cm soil depth, the soil plant transfer coefficient was significantly higher in 2X recommended application rate of 14 C-carbofuran as compared to 1X recommended application rate, in both Bungor and riverine alluvial soils.
The effects of soaking conditions on the quality characteristics of seaweed paste of Kappaphycus alverazii species were studied. Response Surface Methodology (RSM) with a 2-factor, 5-level central composite design (CCD) was conducted to determine the optimum soaking conditions. The interactive effect of dry seaweed: soaking water ratio (X1 = 1: 15-50) and soaking duration (X2 = 30-120 min) on the gel strength (g), whiteness, expansion (%), moisture content (%) and protein content (g/100 g) of the paste were determined. Results showed that the experimental data could be adequately fitted into a second-order polynomial model with multiple regression coefficients (R2) of 0.8141, 0.9245, 0.9118, 0.9113 and 0.9271 for the gel strength, whiteness, expansion, moisture content and protein content, respectively. The gel strength, whiteness, expansion, moisture content and protein content of seaweed paste were dependent on the ratio of dry seaweed to soaking water and also soaking duration. The proposed optimum soaking conditions for the production of seaweed paste is at a ratio of 1:15 (dry seaweed : soaking water) and soaking duration of 117.06 min. Based on the result obtained, the RSM demonstrated a suitable approach for the processing optimization of Kappaphycus alverazii paste.
Cassava chips that exist in the current market have no standardisation and cannot be stacked
nicely into cylindrical container. The objectives of this work are to determine the different dimension of cassava chips produced with different thickness and to develop stackable chips during mass production. Fresh cassava tubers were harvested, washed, peeled and sliced. The thickness measurements used were 1.0 mm, 1.5 mm, 1.75 mm and 2.0 mm and 1.27 mm thickness was measured from commercial potato chips as a controlled sample. Then, it was fried in deep fat fryer with the temperature of 170°C. For each thickness studied, different
numbers of slice (10, 20, 30 and 40 slices) were fried simultaneously. Results showed that there
are 6 shapes of fried chips produced during the frying. To conclude, thickness of the slice and
number of slices fried simultaneously give impact towards the shape of fried chip.
A refined carrageenan is a form of carrageenan, extracted from red algae and purified. Important factors affecting the commercial production of carrageenan after alkaline extraction are the ratio of seaweed to water, temperature, and extraction time. In this study, extraction of refined carrageenan from Kappaphycus alvarezii was conducted on pilot plan scale. Extraction conditions were varied, affecting the final characteristics of the carrageenan product. The optimum conditions investigated for the extraction process included the ratio of seaweed to water, temperature, and extraction time determined using Response Surface Methodology (RSM). Box-Behnken was used to investigate the interaction effects of three independent variables, namely seaweed to water ratio, extraction temperature and extraction time. The results showed that based on the RSM approach, ratio of seaweed to water, temperature and extraction time had a significant influence on the carrageenan. Optimum extraction conditions obtained were seaweed to water ratio of 1:25.22, extraction temperature of 85.80oC and extraction time of 4 h. Under these optimal conditions, the yield obtained was 31.74 % and gel strength was 1833.37 g.cm-2.
The changes on the vegetables oil trading environment might change the foundation of palm oil pricing and induce a structural change to the price model. Failing to take it account the structural change in a data series might lead to misspecification of the actual model. This study, however, showed that structural change was not present in the monthly, January 1983 to July 1995, palm oil price, but it was present on the unconditional variance. The underlying model of this series was ARIMA (3, 1, 0) with ARCH (1). The critical change of the unconditional variance took place in April 1989.
Perubahan dalam suasana perdagangan minyak sayuran boleh mengubah asas harga minyak kelapa sawit. Seterusnya ia merangsang perubahan dalam struktur model harga minyak tersebut. Kegagalan untuk mengambil kira perubahan struktur dalam siri data menjadikan model itu tidak menepati spesifikasi daripada model sebenar. Kajian ini mendapati bahawa perubahan struktur tidak berlaku bagi data harga minyak sawit dari Januari 1983 hingga Julai 1995. Tetapi perubahan berlaku pada varians tidak bersyaratnya. Model asas bagi siri ini adalah ARIMA (3,1,0) dengan ARCH(1). Didapati juga bahawa perubahan yang kritikal bagi varians tidak bersyarat berlaku pada bulan April 1989.
Ulam refers to a group of traditional Malaysian plants commonly consumed as a part of a meal, either in the raw form or after a short blanching process. Many types of ulam are thought to possess blood glucose-lowering properties, but relatively little is known on the effectiveness of ulam in modulating blood glucose levels in humans. This review aims to systematically evaluate the effectiveness of ulam in modulating blood glucose levels in humans. A literature review was conducted using multiple databases with no time restriction. Eleven studies were retrieved based on a priori inclusion and exclusion criteria. In these 11 studies, only Momordica charantia, locally known as "peria katak", was extensively studied, followed by Centella asiatica, locally known as "daun pegaga", and Alternanthera sessilis, locally known as "kermak putih". Of the 11 studies, 9 evaluated the effectiveness of M. charantia on blood glucose parameters, and 7 of which showed significant improvement in at least one parameter of blood glucose concentration. The remaining 2 studies reported nonsignificant improvements in blood glucose parameters, despite having high-quality study design according to Jadad scale. None of the studies related to C. asiatica and A. sessilis showed significant improvement in blood glucose-related parameters. Current clinical evidence does not support the popular claim that ulam has glucose-lowering effects, not even for M. charantia. Hence, further clinical investigation is needed to verify the glucose modulation effect of M. charantia, C. asiatica, and A. sessilis.
Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)).
Relationships between diet and health have attracted attention for centuries; but links between diet and cancer have been a focus only in recent decades. The consumption of diet-containing carcinogens, including polycyclic aromatic hydrocarbons and heterocyclic amines is most closely correlated with increasing cancer risk. Epidemiological evidence strongly suggests that consumption of dietary phytochemicals found in vegetables and fruit can decrease cancer incidence. Among the various vegetables, broccoli and other cruciferous species appear most closely associated with reduced cancer risk in organs such as the colorectum, lung, prostate and breast. The protecting effects against cancer risk have been attributed, at least partly, due to their comparatively high amounts of glucosinolates, which differentiate them from other vegetables. Glucosinolates, a class of sulphur- containing glycosides, present at substantial amounts in cruciferous vegetables, and their breakdown products such as the isothiocyanates, are believed to be responsible for their health benefits. However, the underlying mechanisms responsible for the chemopreventive effect of these compounds are likely to be manifold, possibly concerning very complex interactions, and thus difficult to fully understand. Therefore, this article provides a brief overview about the mechanism of such compounds involved in modulation of carcinogen metabolising enzyme systems.
This paper reviews the application of various modes of solid-phase microextraction (SPME) for the analysis of pesticide residues in fruits and vegetables. SPME is a simple extraction technique that eliminates the use of solvent, and it is applied for the analysis of both volatile and nonvolatile pesticides. SPME has been successfully coupled to both GC and LC. The coupling with GC has been straightforward and requires little modification of existing equipment, but interfacing with LC has proved challenging. The external standard calibration technique is widely used for quantification, while standard addition and internal or surrogate standards are mainly used to account for matrix effects. All parameters that affect the extraction of pesticide residues from fruits and vegetables, and therefore need to be optimized, are also reviewed. Details of the characteristics of analytical procedures and new trends in fiber production using sol-gel technology and molecularly imprinted polymers are discussed.
The purpose of this study was to investigate the biosafety of Vibrio parahaemolyticus in raw salad vegetables at wet market and supermarket in Malaysia. A combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) method was applied to detect the presence of V. parahaemolyticus and to enumerate their density in the food samples. The study analyzed 276 samples of common vegetables eaten raw in Malaysia (Wild cosmos = 8; Japanese parsley = 21; Cabbage = 30; Lettuce = 16; Indian pennywort = 17; Carrot = 31; Sweet potato = 29; Tomato = 38; Cucumber = 28; Four winged bean = 26; Long bean = 32). The samples were purchased from two supermarkets (A and B) and two wet markets (C and D). The occurrence of V. parahaemolyticus detected was 20.65%, with higher frequency of V. parahaemolyticus in vegetables obtained from wet markets (Wet market C = 27.27%Wet Market D = 32.05%) compared to supermarkets (Supermarket A = 1.64%; Supermarket B = 16.67%). V. parahaemolyticus was most prevalent in Indian pennywort (41.18%). The density of V. parahaemolyticus in all the samples ranged from <3 up to >2400 MPN/g, mostly <3 MPN/g concentration. Raw vegetables from wet markets contained higher levels of V. parahaemolyticus compared to supermarkets. V. parahaemolyticus were present in raw vegetables although in low numbers. The results suggest that raw vegetables act as a transmission route for V. parahaemolyticus. This study will be the first biosafety assessment of V. parahaemolyticus in raw vegetables in Malaysia.
Polycyclic aromatic hydrocarbons (PAHs) occur as contaminants in different types of food predominantly from environmental pollution, food packaging and food processing and the levels found depend on the source of the contamination. PAHs emissions from automobile traffic and industry activities were shown to influence the PAHs levels and profiles in vegetables and fruits grown nearby. The present study was carried out to determine the levels of PAHs in samples of tomato, cabbage and apple, collected from six different places of urban and rural areas of plantation in Dhaka city. Eight PAHs listed in the priority pollutant of US Environment Protection Agency and regarded as carcinogens were analyzed in this study. The analytical method involved saponification with methanolic KOH, liquid-liquid extraction with cyclohexane, clean-up on silica gel column and determination by Gas chromatography and mass spectrometry. The mean levels of total PAHs were 9.50 μg/kg in tomato, 8.86 μg/kg in cabbage and 4.05 μg/kg in apple. Of the carcinogenic PAHs, benzo(a)anthracene was the most representative, being found in 89% of all samples analysed. Chrysene was not detected in any sample.