Cassava starch was used as feedstock for production of bioethanol by Saccharomyces cerevisiae. The cassava starch was hydrolyzed using commercial α-amylase and glucoamylase enzymes followed by a batch ethanol fermentation process using saccharified starch slurry. By using 110 g/L of reducing sugar from saccharified starch slurry, the ethanol yield was promising with maximum ethanol concentration of 20.6 g/L recorded after 55 hours of cultivation process. Three different models - the Logistic model, Luedeking-Piret-like equation and Gompertz equation - were used to characterize and explain the cell growth, reducing sugar consumption and production formation, respectively. The kinetic parameters were estimated by fitting the experimental data to the proposed models using non-linear regression analysis. The correlation coefficient r2 values for the Logistic model, Luedeking-Piret-like equation and the Gompertz equation were 0.994, 0.996 and 0.990, respectively. The high correlation coefficient values indicate that the proposed models were able to describe the ethanol fermentation process.
Green leafy vegetables are good sources of carotenoids. Generally, food composition databases related to raw foods are available, but data on cooked foods in Malaysia are still lacking. Since carotenoids are prone to degradation during cooking processes, the present study was undertaken to evaluate the extent of nutrient loss in vegetables subjected to two conventional cooking methods, which were boiling and stir-frying with cooking durations of 4 and 8 minutes. The vegetables selected were Chinese cabbage (Brassica Pekinensis var. cephalata), swamp cabbage (Ipomoea aquatica), spinach (Spinacia oleracea), Ceylon spinach (Basella rubra), red spinach (Amaranthus gangeticus), white spinach (Amaranthus viridis) and tapioca shoots (Manihot utilissima). Percentage losses of nutrients after cooking treatment were calculated based on retention factors. Results obtained showed that stir-frying had reduced lutein content for all vegetables ranging from 8-89% while the effect of boiling for lutein varied (0-428%) with different vegetables at both cooking durations of 4 and 8 min. Boiling for 8 min increased retention of β carotene in all vegetables ranging from 18-380% except for Chinese cabbage and spinach compared with 4 min, while stir-frying generally increased the retention of β-carotene for all vegetables 2-3 times except for spinach. Cooked vegetables have variations in carotenoids composition brought by varying cooking conditions (time and temperature), type of vegetables and the interaction between cooking methods and type of vegetables.
Changes in the physicochemical properties of wheat, sago, tapioca and potato starches were studied
after heating for 1 hour at 100oC, 110oC, and 120oC and for 2 hours at 120oC. These properties were characterised through the swelling behaviour of starch granules, amount of carbohydrate materials leached from the granules, starch paste retrogradation rate and gel strength. For all starches except wheat, the swelling ability, rate of retrogradation and gel strength decreased while solubility increased with increasing temperature and heating time. Wheat starch followed this pattern only when heated at 120oC for 1 and 2 hours. Gel strength correlated well with the ratio of amylose to amylopectin (R) in the leachate. To produce fried crackers with good expansion properties, the granule has to be sufficiently degraded so as to allow more amylopectin to be leached out to achieve R value of 0.25-0.5. This can be achieved by heating wheat starch at 120oC for 1 hour or longer.
Current ethanol production processes utilizing crops such as sugar cane and corn starch have been well established over the decade. Other crop such as cassava is a potential candidate in producing ethanol. However, thermal processes are required to hydrolyze starch for the production of fermentable sugars. The processes are energy intensive and could lead to undesirable by-products generation. In this work, the hydrolysis of cassava starch is studied following an experimental design as a statistical problem solving approach. Central composite design (CCD) is used in order to select the most important variables from the simultaneous study on the effect and influence of operating conditions of bioreactor utilized, namely, pH, temperature and substrate concentration, as well as to optimize the process of cassava starch hydrolysis. From the results obtained, it can be concluded that the cassava starch hydrolysis is enhanced by pH and temperature. Model validations show good agreement between experimental results and the predicted responses.
The aim of this work is to study the effect of hydrocolloids; guar gum (GG), xanthan gum (XG) and carboxymethyl cellulose (CMC) on the physicochemical properties, microbiological quality and sensory properties in order to investigate the potential of applying fermented cassava (tapai ubi) in ice cream. Fermented cassava ice cream (FCI) incorporated with the three types of hydrocolloid was prepared and the protein content, pH value, overrun, colour, hardness, microstructure, FTIR spectrum and sensory acceptance of all samples were determined. Fermented cassava ice cream incorporated with XG showed the highest protein content (14.88%), pH value (pH 6.07), and overrun value (4.27%) as compared to the fermented cassava ice cream incorporated with GG and CMC. Meanwhile, ice cream incorporated with GG possessed the highest L* (94.43) and hardness (3693.15 g) value as compared to XG and CMC. The microstructure study showed that the difference in uniformity at the interface obtained with different types of the hydrocolloids added demonstrated the effect of fat absorption at the air interfaces. The FTIR spectrum investigated indicated that the addition of the fermented cassava to FCI had increased the OH group in the ice cream as compared to the control. All samples were microbial safe as the total plate counts in all samples were below the standard as prescribed in Food Act 1983 with no presence of E. coli . In conclusion, fermented cassava ice cream with XG showed the good quality in terms of its pH value, overrun, total plate count and overall acceptability.
The potential of natural organic compounds as a repellent in biodegradable organic pot is budding into one of the new agriculture innovation. The use of recyclable materials in the production of the pot can reduce the excessive waste disposal problem and thus prevent pollution problems. The objectives are to recycle old newspapers into biodegradable pot for seedling of plants and to repel plant insect pests using organic compounds (Pandanus sp., Petroselinum crispum and Alium sativum). The production of the biodegradable pot incorporates the use of waste materials such as old newspapers and coconut husk together with natural organic materials such as tapioca flour, Pandanus amaryllifolius (pandan leaf), Petroselinum crispum (parsley) and Alium sativum (garlic). This product is distinguishable among others as it is environmental-friendly since the pot can naturally break over time (biodegradable). The aroma from the Pandanus amaryllifolius, Petroselinum crispum and Alium sativum can repel flying and crawling insect that may attack the crops. The organic insect-repellent biodegradable pot has a potential in replacing plastic polybags since the crops planted in the pot can be directly replanted in the soil without the need of disposing the pot. Root is allowed to grow through the pot where later on, it will be degraded. Apart from that, this pot has high commercial values since it is easy to be handled, low in production cost, eco-friendly where only recyclable and natural organic materials were used, and the most crucial point is it can act as an insect repellent.
Increasing environmental concerns have led to greater attention to the development of biodegradable materials. The aim of this paper is to investigate the effect of banana leaf fibre (BLF) on the thermal and mechanical properties of thermoplastic cassava starch (TPCS). The biocomposites were prepared by incorporating 10 to 50 wt.% BLF into the TPCS matrix. The samples were characterised for their thermal and mechanical properties. The results showed that there were significant increments in the tensile and flexural properties of the materials, with the highest strength and modulus values obtained at 40 wt.% BLF content. Thermogravimetric analysis showed that the addition of BLF had increased the thermal stability of the material, indicated by higher-onset decomposition temperature and ash content. Morphological studies through scanning electron microscopy (SEM) exhibited a homogenous distribution of fibres and matrix with good adhesion, which is crucial in improving the mechanical properties of biocomposites. This was also attributed to the strong interaction of intermolecular hydrogen bonds between TPCS and fibre, proven by the FT-IR test that observed the presence of O-H bonding in the biocomposite.
Application of sewage sludge as fertilizer can be beneficial for sustainable agriculture as it could largely account for nitrogen and phosphorus demand for crops and has lower costs compared to other disposal routes, e.g., incineration, and sanitary landfills. This study evaluates the feasibility of pilot-scale pelletization of sewage sludge for non-food crops (e.g., ornamental plants). The co-pelletization method was designed by mixing sewage sludge and binder (tapioca starch) at a 9:1 sludge-to-starch weight ratio. The amount of nitrogen (N), phosphorus (P), and potassium (K) of the resultant pellets were determined at 5.7%, 4.9%, and 0.2%, respectively. Following Malaysian and US Standards, non-essential elements and pathogenicity of the pelletized sewage sludge were measured below the predetermined limits and hence safe for agricultural application. The planting trial using 50% inorganic fertilizer + 50% sewage sludge pellets exhibited a promising result on the growth of the flowering plant Celosia plumosa, with having better dimension and color, 20% higher in height, 4% more chlorophyll content, 54% more leaf, 43% greater stem growth, and 27% more flowers compared to control. Likewise, the planting trial on Tagetes erecta resulted in 10.5% wider leaf, 10.6% heavier leaf dry weight, and 12.5% more chlorophyll content compared to control with full usage of inorganic fertilizer. By considering liquidities to operate the production facility, the economic analysis estimated that the production cost per ton of pelletized sewage sludge produced was USD 0.98.
The effect of consuming large amounts of cassava leaves on thyroid function and urinary iodine was studied. Twenty volunteers were given 200 gm of boiled cassava leaves twice a day for 12 consecutive days. Thyroid hormones triiodothyronine and thyroxine were significantly lower by 9 days. Urinary iodine excretion was also significantly decreased. Cassava leaves, consumed in large amounts by aborigines, probably caused goitres by decreasing iodine absorption.
Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.
Antioxidants play an important role in inhibiting and scavenging radicals, thus providing protection to humans against infections and degenerative diseases. Literature shows that the antioxidant activity is high on herbal and vegetable plants. Realizing the fact, this research was carried out to determine total antioxidant activity and the potential anticancer properties in three types of selected local vegetable shoots such as Diplazium esculentum (paku shoot), Manihot utillissima (tapioca shoot) and Sauropous androgynus (cekur manis). The research was also done to determine the effect of boiling, on total antioxidant activity whereby samples of fresh shoots are compared with samples of boiled shoots. In every case, antioxidant activity is compared to alpha-tocopherol and two methods of extraction used are the organic and the aqueous methods. Besides that, two research methods used were the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) with absorbance of 500nm and 532nm respectively. Oneway ANOVA test at P<0.05 determines significant differences between various samples. In the cytotoxic study, the ethanolic extract and several cell lines i.e. breast cancer (MDA-MB-231 and MCF-7), colon cancer (Caco-2), liver cancer (HepG2) and normal liver (Chang liver) were used. The IC(50)-value was determined by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The antioxidant study found that all the samples in both aqueous and organic extraction were significantly different. The total antioxidant activity values of aqueous extract in descending order are as follows: M. utilissima (fresh) >D. esculentum (fresh) >S.androgynus (fresh) > M.utilissima (boiled) > D. esculentum (boiled) > S.androgynus (boiled). It also was found that S.androgynus shoots ethanolic extract was able to inhibit the viability of the breast cancer cell lines, MDA-MB-231 with the IC50 value of 53.33 micrograms/ml. However, S.androgynus shoots and D. esculentum shoots ethanolic extracts did not inhibit the viability of MDA-MB-231 cell line. While, the tapioca shoot ethanolic extract was able to inhibit the viability of MCF-7 cell line with the IC(50) value of 52.49 micrograms/ml. S.androgynus shoots and D.esculentum shoots ethanolic extracts did not give an IC(50) value against the MCF-7 cell line. S.androgynus, tapioca and D.esculentum shoots ethanolic extracts did not show cytotoxic effect against the Caco-2 and HepG2. There was no IC(50)-value from any sample against Chang Liver cell line. In conclusion, the antioxidant activity of both fresh and boiled samples were higher than alpha-tocopherol, although fresh vegetable shoots were found to be higher in antioxidant activity compared to boiled shoots. This study also suggested that S.androgynus shoots and tapioca shoots have potential as an anticancer agent against certain breast tumours.
Feeding responses of subterranean termites Coptotermes curvignathus (Holmgren) and Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae) to bait matrices supplemented with various sugars, amino acids, and cassava were evaluated both in the laboratory and field. The results indicated that the two termite species consumed significantly different amount of filter papers that had been treated with various types and concentrations of sugars and amino acids. Based on consumption and survival data, filter papers with 3% glucose and 3% xylose were among the most consumed by C. curvignathus and C. gestroi, respectively. Both termite species consumed more of the filter papers treated with 3% casein than filter papers treated with L-alanine. Both species had a comparable survival rate compared with those in the controls. Results from laboratory and field trials on bait prototypes indicated that C. gestroi consumed more bait prototypes containing cellulose, 3% xylose, 3% casein, and cassava, whereas C curvignathus consumed more bait prototype containing cellulose, 3% glucose, and cassava, than on pure crystalline cellulose baits. Thus, with an improved and cost-effective bait formulation, a much wider control of subterranean termite colonies could be achieved.
This study aimed to represent the first report of the ovicidal and larvicidal activity of the methanolic leaf extract of Manihot esculenta (cassava) against eggs and larvae of susceptible and resistant strains of Trichostrongylus colubriformis. As well as, to determine the total tannin compounds, antioxidant activity and toxicity of the extract. The egg hatch test was used to evaluate ovicidal activity against unembryonated eggs, whereas larval feeding inhibition assay and MTT-formazan assay were used to evaluate larvicidal activity against first (L(1)) and infective (L(3)) larvae, respectively. The results showed no significant differences were detected between the sensitivities of susceptible and resistant strains of T. colubriformis to the extract. Eggs, L(1) and L(3) were significantly affected (P<0.001) compared with negative control, and L(1) were more sensitive than the eggs and L(3). The total tannin compounds were investigated using tannin quantification assay and determined by 254.44 TAE/mg. The antioxidant activity was evaluated using the DPPH radical scavenging assay and the median inhibition concentration (IC(50)) was determined by 2.638 mg/ml. Acute oral toxicity at dose of 5,000 mg/kg, and sub-chronic oral toxicity at 500 and 1,000 mg/kg of the extract were observed in male and female Sprague-Dawley (SD) rats. The acute oral toxicity revealed that the median lethal dose (LD(50)) of methanolic extract of cassava leaves on SD rats was greater than 5,000 mg/kg, whereas the sub-chronic oral toxicity did not show observed adverse effects at 500 and 1,000 mg/kg per day for 28 days. In conclusion, the methanolic extract of cassava leaves has direct ovicidal and larvicidal activity against T. colubriformis strains with a safety margin for animals, and it may be potentially utilized as a source of natural antioxidants.
The effects of eight diets (atta flour, wheat flour, self-rising flour, rice flour, custard powder, corn flour, tapioca starch, and potato starch) on the development of the red flour beetle, Tribolium castaneum (Herbst), reared at 29-31 degrees C and 66-70% RH were assessed. Five pairs of male and female T. castaneum were reared on the respective diets for 28 d before the experimental setup was dismantled and adult counts were recorded. In another experiment, the insects were allowed to mate and oviposit in each flour or starch type over a period of 7 d before being removed. The counting of pupae and adult emergence began on the day of emergence and was continued on a daily basis until day 140. Proximate analysis was performed for chemical composition of each diet, and the numbers of new adults that developed were found to be positively correlated (r2 = 0.97; P < 0.05) with the protein content and negatively correlated (r2 = 0.93; P < 0.05) with the carbohydrate content. For T. castaneum, the suitable diets were ranked as follows: atta flour > wheat flour > self-rising flour > rice flour > custard powder > corn flour > tapioca starch > potato starch. T. castaneum larval development to the pupal and adult stages developed significantly faster in atta flour (P < 0.05) than in the other diets, and the greatest number of progeny was produced from beetles reared on atta flour. Fewer adults emerged from wheat flour, self-rising flour, and rice flour, and no new emergences were recorded for the remaining diets. Developmental rate was much slower in beetles reared on diets in which a low number in progeny was produced. These data illustrate that different diets can influence the sustainability of these insects and affect their development and growth.
In September 1997, plants of Hibiscus manihot (locally called nambele) were observed on Vaitupu Island, Tuvalu, exhibiting an angular leaf mosaic and chlorosis that was not always clearly discernible. Electron microscopy of negatively stained sap from affected leaves revealed the presence of numerous isometric virus particles 28 nm in diameter. Poly-acrylamide gel electrophoresis of purified virus gave a single protein band of Mr 38,000 similar to that of the carmoviruses. Immunosorbent electron microscopy tests with antisera kindly provided by N. Spence showed the virus to be hibiscus chlorotic ringspot carmovirus (HCRSV) (1). This virus is also reported from El Salvador, the U.S., Australia, Thailand, Malaysia, Fiji, the Solomon Islands, and Vanuatu. It is not known how the virus reached Tuvalu but we suspect it was via infected cuttings, which were imported for the production of food supplements to combat acute deficiencies of vitamins A and C in the population. The virus is most likely to have been disseminated throughout the islands and atolls of Tuvalu through infected cuttings. Local spread within fields could occur through contaminated hands and cutting implements because of the ease with which the virus is mechanically transmitted. Reference: (1) H. E.Waterworth et al. Phytopathology 66:570, 1976.
The common industrial starches are typically derived from cereals (corn, wheat, rice, sorghum), tubers (potato, sweet potato), roots (cassava), and legumes (mung bean, green pea). Sago (Metroxylon sagu Rottb.) starch is perhaps the only example of commercial starch derived from another source, the stem of palm (sago palm). Sago palm has the ability to thrive in the harsh swampy peat environment of certain areas. It is estimated that there are about 2 million ha of natural sago palm forests and about 0.14 million ha of planted sago palm at present, out of a total swamp area of about 20 million ha in Asia and the Pacific Region, most of which are under- or nonutilized. Growing in a suitable environment with organized farming practices, sago palm could have a yield potential of up to 25 tons of starch per hectare per year. Sago starch yield per unit area could be about 3 to 4 times higher than that of rice, corn, or wheat, and about 17 times higher than that of cassava. Compared to the common industrial starches, however, sago starch has been somewhat neglected and relatively less attention has been devoted to the sago palm and its starch. Nevertheless, a number of studies have been published covering various aspects of sago starch such as molecular structure, physicochemical and functional properties, chemical/physical modifications, and quality issues. This article is intended to piece together the accumulated knowledge and highlight some pertinent information related to sago palm and sago starch studies.
The relationship between malnutrition, goitre and thyroid hormones was studied among Aborigines and Malays in Ulu Langat, Malaysia. Fifty Aborigines aged >=7years were selected randomly for anthropometric, clinical and hormonal assessment. Fifty Malays of similar age from the nearby Malay village were chosen as controls. The Aborigines had a higher prevalence of malnutrition and goitre compared to the Malays. The prevalence of goitre was 26.5% amongst Aborigines and 19.6% among the Malays. All the nutritional indexes measured were significantly different between the two communities, especially among females. The differences corresponded to significant differences in levels of thyroid-stimulating hormone (TSH) measured using a highly sensitive TSH assay. By univariate analysis the increase in TSH corresponded to the decrease in body mass index (BMI). On the other hand, no association was found between BMI and goitres. No thyroid autoantibodies were detected and all subjects were clinically euthyroid and had normal thyroxine and triidothyronine levels. However, consumption of cassava conferred a four-fold risk of developing goitres. The high prevalence of goitres in malnourished subjects in this region which is not known to be iodine deficient could be due to cassava consumption.
The effects of orange sweet potato flour addition to tapioca starch on the expansion, oil absorption,
bulk density, water absorption index (WAI), water solubility index (WSI), hardness and colour of fried extruded fish crackers were investigated. The microstructure properties were assessed by Field Emission Scanning Electron Microscope (FESEM) and the sensory properties of fried extruded fish crackers were determined by quantitative descriptive analysis method. The shape and texture of the product were similar to that of normal breakfast cereal. Light brownish and slightly harder texture was obtained with addition of orange sweet potato flour to tapioca starch in the fried extruded fish crackers. The bulk density and water solubility index (WSI) increased with the increase in orange sweet potato flour addition. However, water absorption index (WAI), linear expansion, expansion ratio, volume expansion and oil absorption decreased as the amount of orange sweet potato increased. The microstructure studies revealed that fried extruded fish crackers with high percentage of orange sweet potato flour had small air cells and thick cell wall. The fried extruded fish crackers with 30% fish, 14% orange sweet potato flour and 56% tapioca starch had high crispiness score and accepted by the trained panellists.
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.
A survey was conducted to investigate the level of consumption of ‘ulam’ in Selangor State among 252 adults (> 17 years) (male 28.6%, female 71.4%) of major ethnics (Malays-51.6%; Chinese-30.5%; Indians-17.5%) with the mean age of 42.7 ± 13.9 years. Consumption data were collected using 24 hours duplicate samples together with questionnaire on perceptions of ‘ulam.’ Results showed that ‘ulam’ was preferred by majority of the subjects (82.1%), especially amongst Malays (92.3%). A total of 52% of the subjects consumed partially or boiled ‘ulam.’ Factors that affect their preferences on ‘ulam’ were the perception of therapeutic effects of the ‘ulam’ towards health, its good taste and unique
aroma. The most consumed ‘ulam’ were cucumber (Cucumis sativus) (60.6%) ‘kacang botol’ (Psophocarpus tetragonolobus) (33%), Indian pennywort (Hydrocotyle asiatica) (31.5%), lettuce (Lactuca sativa) (27.6%), ‘petai’ (Parkia speciosa) (29%) and ‘ulam raja’ (Cosmos caudatus) (21.9%). The most preferred partially or boiled ‘ulam’
were tapioca shoot (Manihot esculenta) (31.5%), ocra (Hibiscus esculentus) (12.5%) and ‘jantung pisang’ (Musa sapientum) (20.1%). There was no significant difference (P > 0.05) amongst the three different ethnic groups on the consumption of ‘ulam’ and the median for total intake per day was within the range of 30-39 g/day. Ulam is a potential
source for increasing vegetable consumption to meet recommendation by World Health Organization (WHO), which is 400 g per day.
Keywords: Adults; perception; ‘ulam;’ Selangor State