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Solid waste management in the Maldives is under extreme stress due to the unique nature of its geography and economic structure. Plastic pollution has been a growing concern for the Maldives. The purpose of this research study was to identify the current consumption patterns of the plastic items particularly single use plastics (SUP) as well as identifying the level of knowledge among the consumers about the SUP and consumer behavior to change and the public confidence level in drinking tap water. A questionnaire was used as the key instrument for primary data collection in this study. It enabled researchers to collect data in a standardized way so that the data were internally consistent for analysis. A total 817 out of 1095 responded to the survey from across the Maldives. The overall finding suggested that the majority of the consumers in the Maldives are still using single-use plastic in their everyday life. However, large percentage of consumers know the benefits of reducing plastic on human health and environment. With regard to the challenges or barriers in implementing the single-use plastic, consumers identified lack of available alternatives, higher costs, inconvenient transport, lack of hygiene, and time requirement. In addition, majority of the participants do not trust the quality of tap water in the country for various reasons, therefore, they prefer to consume bottle water. It seems there is an immense and urgent need to explore ways to increase consumers awareness and subsequent efforts to reduce the consumption of plastic in the country.

Labisa pumila var alata contains bioactive compounds such as gallic acid that is of use for pharmaceutical and nutraceutical industries. Aqueous extraction is the traditional method that extracts phytochemicals from plant material. The study aimed to find the optimum condition for maximum gallic acid yield from ground L. pumila leaves using aqueous extraction. The results revealed that the maxium gallic acid yield obtained was at 1:10 sample to water ratio for 8 h at 50 °C. The maximum yield of gallic acid obtained was 1.025 mg gallic acid per g dried leaves (mg/g). The identification of gallic acid was done on Liquid Chromatograph Mass Spectrometer Quadrupole Time-of-Flight (LCMS-Q-TOF) by comparison to that of reference standard. The morphological structure of the extract that was obtained at optimum condition showed less denaturation of cell wall which indicates that still some gallic acid could be trapped in the sample matrix and other methods need to be employed to release them.

The traditional ways of protein extraction is disadvantageous from both economic and environment perspective. In this study, ultrasonic assisted extraction, UAE technique was used for the first time for the optimization process of extracting proteins from Eurycoma longifolia roots. The experiments demonstrated the successful effect of applying eccentric agitation with UAE to provide a combination of agitation and sonication to extract the proteins in short extraction times. Central composite design (CCD) was used to optimize the Ultrasonic-assisted extraction of proteins from roots of Eurycoma longifolia by water. Response surface methodology (RSM) was employed to investigate the effects of five independent variables; particle sizes ( A ), extraction temperatures ( B ), agitation speeds ( C ), amplitude ( D ) and duty cycle ( E ). The second enhanced model ( Y 2 ) prevailed to be more efficient in protein recovery with optimum conditions of A : 0.022 ± 0.022 mm, B : 49 °C, C : 1314 rpm, D : 9 W and E : 63% UI : 2.94 W·cm −2 was 9.543 ± 0. 946%. High agitation speed didn’t only affect the solvent properties, the diffusion of the solutes from the particles, cooling the extraction temperature, but influenced the distribution of cavitation bubbles and their impact on the solid particles. UAE was found to minimize the extraction of the same amount by conventional extraction 7-fold times. The results obtained in this study have exposed the capability of ultrasonic assisted extraction, UAE technology in extraction of protein from E. longifolia roots. Further works are nevertheless required to provide deeper understanding of the mechanisms involved to facilitate the development of optimum system applicable to the industry.

The biosphere is polluted with metals due to burning of fossil fuels, pesticides, fertilizers, and mining. The metals interfere with soil conservations such as contaminating aqueous waste streams and groundwater, and the evidence of this has been recorded since 1900. Heavy metals also impact human health; therefore, the emancipation of the environment from these environmental pollutants is critical. Traditionally, techniques to remove these metals include soil washing, removal, and excavation. Metal-accumulating plants could be utilized to remove these metal pollutants which would be an alternative option that would simultaneously benefit commercially and at the same time clean the environment from these pollutants. Commercial application of pollutant metals includes biofortification, phytomining, phytoremediation, and intercropping. This review discusses about the metal-accumulating plants, mechanism of metal accumulation, enhancement of metal accumulation, potential commercial applications, research trends, and research progress to enhance the metal accumulation, benefits, and limitations of metal accumulators. The review identified that the metal accumulator plants only survive in low or medium polluted environments with heavy metals. Also, more research is required about metal accumulators in terms of genetics, breeding potential, agronomics, and the disease spectrum. Moreover, metal accumulators' ability to uptake metals need to be optimized by enhancing metal transportation, transformation, tolerance to toxicity, and volatilization in the plant. This review would benefit the industries and environment management authorities as it provides up-to-date research information about the metal accumulators, limitation of the technology, and what could be done to improve the metal enhancement in the future.

Honey is an extract of floral and secretions from a variety of bees. Some honey manufactures adulterate pure honey with industrial sugar, chemicals, and water either directly or indirectly. Many methods have been developed to detect honey adulterants including physicochemical analysis, microscopy, chromatography, immunoassay, thixotropicity, DNA metabarcoding, sensors, and spectroscopy. However, the most promising methods for the development of a portable test kit for honey adulterant detection are ELISA, electronic tongue, and NIR. The most sensitive and accurate method is NIR. These methods have shown satisfactory results when used individually or combined. Further research is still required to trial different combinations of methods to improve accuracy and the ability to detecting a wide variety of adulterants simultaneously. There is a need to develop a portable honey adulterant detection method, such as NIR spectroscopy using a smartphone.

Ficus deltoidea or ‘mas cotek’ is among the well-known traditional herbal plants in Peninsular Malaysia that drawn much attention of growers worlwide because of their bioactive compounds used in reducing the risk of cancer, diabetes and heart diseases. Vitexin and isovitexin are two remarkable compounds of flavone C-glycosides found in the leaves extracts of Ficus deltoidea and chosen as biomarkers due to their abundant phytochemical and pharmacological activities. The conventional extraction methods have been used for decades. However, in this research, extraction of vitexin and isovitexin were improved by the implementation of microwave. Microwave-assisted hydrodistillation (MAHD) extraction can enhance the extraction efficiency by disrupting the plant cell wall, facilitate the solvent penetration into plant material and allow the intracellular product release by using microwave energy to heat solvents in contact with a sample and accelerate the mass transfer of target compounds from the sample matrix. The effect of main factors which were extraction temperature, irradiation time, microwave power and plant material to water ratio were investigated to obtain a maximum vitexin and isovitexin yield. As a result, the best condition that has been determined for highest vitexin and isovitexin production were under 70°C for 120 minutes at water to raw material ratio 1:10 using 500W power. This best condition of extraction of vitexin and isovitexin was finalized based on its highest yield obtained from the microwave which were 33.40 ± 0.98 (% w/w) with 1.152-fold and 11.38 ± 0.86 (% w/w) with 0.65-fold, respectively. The conventional aqueous extraction was used as a control throughout the whole processes. High performance liquid chromatography (HPLC) was used to analyse yield of vitexin and isovitexin in the extracts

Central composite designs (CCDs) for UAE and WE were established by seven and five extraction factors, respectively, to determine their optimum conditions that maximized the saponins yields. These optimum conditions were employed successively to establish a sequential extraction (SE) of saponins from Eurycoma longifolia roots. Results identified the agitation speed as an influencing factor in altering the interactive effects of the extraction factors in UAE and WE. Optimized conditions illustrated that higher agitation speeds increased the yields of saponins in WE while UAE preferred lower agitation speed ranges. This implied that the high agitation speeds decreased the collision of microjets and particles and hence the the decrease of sonication efficiency. The SE extraction was proposed by initial sonication of the plant sample for a duration of 5 minutes and 29 seconds to 10 minutes followed by conventional WE for 20-25 minutes.

Optimization of protein yields in water extracts that were obtained from Jackiopsis ornata roots by Microwave assisted extraction (MAE) was established by a Circumscribed Central Composite Design (CCCD). MAE proved to be an optimum choice for the protein extraction. The highest yield (20.425±108) was obtained with the parameters liquid to solid ratio (S= 30:1), particle size (P=0.022±0.002mm (radius), temperature (T= 65°C); microwave power (W= 300W) and extraction time (t= 20 minutes). Statistical analysis illustrated the adequacy of the generated full quadratic equation with ad high values of the coefficient of determination (R2), adjusted coefficient of determination R2adj and predicted coefficient p of determination R2pred The p value of the Lack of Fit test illustrated the adequacy of the model. The optimization conditions of extracting the protein was predicted to be with the parameters S: 26, P: 0.0284; T: 65 °C; P: 303 W and t: 20 min. The high efficiency of MAE to obtain J. ornata protein extract encouraged further application on pilot and industrial scale.

Amperometric biosensor for glucose content measurement in Malaysian stingless bee honey was developed using screen printed carbon electrode (SPCE) integrated with paper disc immobilized with enzyme Glucose Oxidase (GOx) using simple physical adsorption method. The paper-based biosensor required only 8 μL of sample solution for glucose analysis. The calibration of glucose biosensor is linear between 0.5 mM to 4.5 mM (R2= 0.9925) and has a detection limit of 0.15 mM. Interference study on several compound affecting the biosensor response and storage stability was investigated. In addition, its performance was demonstrated in the analysis of six honey samples. The results obtained using glucose biosensor was validated by high performance liquid chromatographic (HPLC) method. The addition of glucose in pure honey at various concentration were also tested by this paper-based biosensor where the current obtained shows increasing trend with the addition of glucose. From this research, it can be concluded that, the prototype sensor to determine glucose adulteration in stingless bee honey was successfully developed.

Commercial honey is widely available in the market, raising questions whether the honeys are good in quality or otherwise, Thus, this research was designed to compare the quality of harvested stingless bee honey and commercial honey available in the Malaysian market by measuring their sugar profile and enzyme activity. The analysis showed that the honey contained moisture between 16.6% - 32.1%, various sugar starting with fructose (15.03 – 48.44 g/100 g), glucose (12.16 – 40.09 g/100 g), sucrose (H. Itama and G.Thoracica showing comparable results with past studies and within the limits of Malaysian Standard. However, all honey samples demonstrate lower enzyme activity suggesting that honey from stingless bee has low enzyme activity compare to Apis mellifera honey.

Rihaakuru is a cooked fish paste from the Maldives, consumed as a condiment with rice and other food. One of our studies confirmed that Rihaakuru contained up to 10 different biogenic amines, with histamine in excess of 500 ppm (n = 28). This may cause histamine poisoning, with symptoms such as skin rashes, vomiting and fever, thus making it a food security issue in the Maldives. Another study by us developed a regression model that predicted the rate and amount of histamine removal by diamine oxidase (DAO) under varied pH and salt concentrations in the tuna soup used to manufacture Rihaakuru. Based on the results of these studies, a conceptual design in producing histamine-free Rihaakuru is described in this paper. This conceptual design could be used as a guideline in the actual production of histamine-free Rihaakuru. Histamine-free Rihaakuru could be a potential export containing high protein and omega-3. Practical Applications Rihaakuru is a fish paste that is rich in protein, minerals and contains omega 3. However, Rihaakuru can contain more than 500 ppm histamine that may cause food poisoning. This histamine originates from poor quality raw fish used to manufacture this product. The manufacture of Rihaakuru is seen as a way of using poor quality fish. Rihaakuru is generally stable in terms of bacterial deterioration and the only issue is the high histamine level. This research demonstrated on a novel method to prevent histamine food poisoning using diamine oxidase, to degrade the histamine in the fish soup during the manufacture of Rihaakuru. This enables the manufacture of histamine free-Rihaakuru and has the potential to be applied to other foods containing histamine.

The growing demand for honey in the market has led to the occurrence of the tampering honey with foreign substances and increases the production of artificial honey. Due to this concern, this study works on the physicochemical and microbial characterization of stingless bee honey. The physicochemical analysis showed that the honey possessed pH (2.51–3.26), free acidity (121.1 to 318.7 meq/kg), moisture (19.4–30.9%), electrical conductivity (0.33–0.69 mS/cm), ash content (2.75–4.31 g/100g), Hydroxymethylfurfural (HMF) content (35.4 to 461.7 mg/kg) and diastase activity (2.71 to 6.11 DN). Also, sugar profile of honey showed that the honey contained fructose (15.03–32.52 g/100g), glucose (12.17–34.55 g/100g) and sucrose (0.01–7.29 g/100g). The harvested honey, H1, and H2 have the highest potential to become an antibacterial agent to treat disease compared to commercial honey samples because they were active against Gram-negative bacteria. All analyzed samples were within the maximum limit of the quality criteria set by the Malaysian Kelulut Standard and Codex Alimentarius except for free acidity, HMF, and Diastase Number. All the data obtained is vital in order to create a specific statute for stingless bees honey in Malaysia that may help to protect the consumer from purchasing adulterated honey.

Histamine is a biogenic amine that forms in a variety of foods and can cause food poisoning at high concentrations (>500 ppm). In situations where the formation of histamine in food cannot be prevented through refrigeration, diamine oxidase (DAO) enzyme may be used to degrade histamine to safe levels. The aims of this work were to apply DAO in model (buffer) and real (cooked tuna soup used in the manufacture of a fish paste product, Rihaakuru) systems, in order to obtain predictions for the rates and amounts of histamine degradation. The two systems were set up with a constant concentration of histamine (500 mg/L) and the DAO enzyme (2534 units/L) at a temperature of 37°C, agitation at 100 rpm and an incubation time of 10h with variable pH (5-7) and salt concentrations (1-5%). A total of 15 experiments were designed for each system using central composite design (CCD). The data from these experiments were fitted into regression models; initially the data were used to generate an exponential decline model and then the data from this were fitted into a secondary response surface model (RSM) to predict the rate and amount of histamine degradation by DAO. The model system results indicated that DAO activity was not significantly affected by salt (p>0.05), and that activity reached a maximum within the pH range of 6-6.5 with an optimum at pH 6.3. However, the results obtained with the tuna soup model showed that the optimum oxidation of histamine using DAO occurred between pH 6-7 and salt 1-3%. This study defined the conditions for the use of DAO to degrade 500 mg/L of histamine in tuna soup used to manufacture Rihaakuru. The models generated could also be used to predict the rate and amount of histamine degradation in other foods that have similar characteristics to tuna soup.

The biogenic amine concentration in Rihaakuru (a fish paste) (n=28), obtained from different parts of the Maldives (North, South, and Central), was determined by HPLC. Ten biogenic amines were detected; agmatine, not detected (ND) - 161ppm; cadaverine, ND - 387ppm; histamine, ND - 5487ppm; putrescine, ND - 290ppm; phenylethylamine, ND - 23ppm; serotonin, ND - 91ppm; spermine, ND - 329ppm; spermidine, ND - 79ppm; tryptamine, ND -5ppm; and tyramine, ND - 50ppm. Nine biogenic amines were found in 3 samples, 8 in 10 samples, 7 in 6 samples, 6 in 3 samples, 4 in 5 samples, and 1 was found in 1 sample. Histamine was detected at levels that are regarded as a risk to human health. Fourteen isolates were selected from two randomly selected samples out of the 28 samples of Rihaakuru and screened for histamine production. Twelve of the 14 isolates produced histamine, with the highest histamine producers being Bacillus massiliensis Nai5 (6.65ppm) and Bacillus polyfermenticus (5.58ppm); while Bacillus malacitensis produced the least (0.5ppm).

Rihaakuru is a traditional Maldivian side dish consumed mainly with rice. It is a thick brown fish paste, made from tuna after prolonged heating. Samples tested were found to have a low water activity (0.55-0.8), slightly acidic pH (5.62-6.18) and moderate salt content (1.4-1.6%). The product was found to be rich in polyunsaturated fatty acids such as omega-3, had high protein content (56-59%) and an energy level of 13.8 kJ/g. The product had a low microbial count (1.54-2.31 log(10) cfu/g). The bacteria isolated belonged to the Bacillaceae (Genus Clostridium, and Bacillus), Streptococcaceae (Genus Streptococcus), Micrococcaceae (Genus Staphylococcus), and Corynebacterium. The product appears to be a nutritious and shelf-stable product.

Biogenic amines have been reported in a variety of foods, such as fish, meat, cheese, vegetables, and wines. They are described as low molecular weight organic bases with aliphatic, aromatic, and heterocyclic structures. The most common biogenic amines found in foods are histamine, tyramine, cadaverine, 2-phenylethylamine, spermine, spermidine, putrescine, tryptamine, and agmatine. In addition octopamine and dopamine have been found in meat and meat products and fish. The formation of biogenic amines in food by the microbial decarboxylation of amino acids can result in consumers suffering allergic reactions, characterized by difficulty in breathing, itching, rash, vomiting, fever, and hypertension. Traditionally, biogenic amine formation in food has been prevented, primarily by limiting microbial growth through chilling and freezing. However, for many fishing based subsistence populations, such measures are not practical. Therefore, secondary control measures to prevent biogenic amine formation in foods or to reduce their levels once formed need to be considered as alternatives. Such approaches to limit microbial growth may include hydrostatic pressures, irradiation, controlled atmosphere packaging, or the use of food additives. Histamine may potentially be degraded by the use of bacterial amine oxidase or amine-negative bacteria. Only some will be cost-effective and practical for use in subsistence populations.

Impedance microbiology is the detection and quantification of bacterial growth by measuring the electrical impedance change during microbial metabolism which allows the identification of viable and nonviable cells. This method uses various techniques to improve the sensitivity and selectivity of bacterial detection, and these include equivalent circuit analysis, interdigitated array microelectrodes (IDAMs), microchips, biosensors, and nanomaterials for bacterial detection. The advantage of impedance microbiology is that the data can be obtained within a short time, with good sensitivity and selectivity using a small sample. The disadvantages of impedance testing include the contamination issues, the need for specific selective media, and interference from food matrices. Various rapid microbiological testing platforms involving impedance continue to be explored as tools to manage food safety and quality.

The aim of this work was to explore suitable methods (bacteria/enzyme) to degrade histamine as an alternative method for the control of histamine in food. Histamine degradation by bacteria was studied in trypticase soy broth containing 500 ppm of histamine at 30°C for 9 days. The bacteria studied were Lactobacillus sakei (AGR 37, AGR 46, Lb 706), Arthrobacter crystallopoietes DSM 20117 and Vergibacillus halodonitrificans Nai18. All L. sakei strains reduced histamine to about 50% while V. halodonitrificans Nai18 degraded histamine by 30%. A. crystallopoietes DSM 20117 did not degrade histamine. Diamine oxidase (DAO), however, degraded histamine (500 ppm) to an undetectable level (

Rihaakuru is a shelf stable fish paste product formed from a fish soup prepared from tuna. Histamine contamination is a food safety issue with this product that is manufactured from tuna fish that has been temperature abused. Histamine concentrations decreased between 31% and 73% in Rihaakuru stored for 10 months at either −80, 4 or 30 °C. This appears to be a property of the product as histamine solutions are reported to be stable, at least under frozen storage. The risk of histamine food poisoning due to Rihaakuru may reduce during the storage of the product.

Histamine is a biogenic amine, which can cause food poisoning when present at high concentrations (>500 ppm). In situations where the formation of histamine in food cannot be prevented through traditional methods such as refrigeration, diamine oxidase (DAO) enzyme may be a suitable method to reduce histamine concentration to safe levels. The aim of this work was to apply the enzyme to cooked tuna soup, which is one of the manufacturing steps of Rihaakuru, which often contains high levels of histamine. The DAO activity in tuna soup containing 500 ppm of histamine, at various pH values (5-7) and salt concentrations (1-5%) were examined. A central composite design (CCD) was used which contained a total of fifteen experiments. Histamine was completely degraded (L = 0) at pH 7 and 6.5, and at salt level of 2 and 3%. The rate of histamine reduction was optimum (r > 5) at pH 7 and salt level 3%. To obtain complete histamine degradation and optimum rate of degradation simultaneously, salt 3% and pH 7 was suggested.