Green coffee beans are stored for a certain period and under certain conditions until they are finally utilized. The storage period may depend on customer demand while the storage conditions depend on where the coffee beans are stored. Thus, this research emphasizes the physicochemical changes that occur in Liberica coffee beans during storage under the Malaysian
climate (average temperature and relative humidity of 29.33ºC and 71.75% respectively). The changes in the physico-chemical (coffee size, mass, densities, colour, proximate analysis, sucrose, chlorogenic acid content) and microbiological (yeast and mould count) properties were evaluated during eight months of storage. After the storage, the physical properties of the coffee changed as the coffee beans expanded in size, reduced in mass and density and became brighter in colour. Changes in the chemical properties were also detected where the moisture decreased and the ash content increased. In addition, the sucrose level was found to decrease with a corresponding increase in chlorogenic acid. During storage, the counts of yeast and mould were reduced. Model equations describing the changes in the properties were developed. The overall conclusion was that the coffee beans reduced in quality during storage.
Supercritical carbon dioxide (SC-CO2 ) is a non-thermal technique implemented by food, pharmaceutical, and similar industries with the aim of inhibiting the microorganisms and apply effective sterilisation. Presently, limited number of studies has reported the application of SC-CO2 on fresh chicken meat. The present work therefore aimed to reveal the microbial and physicochemical quality of the SC-CO2 -treated fresh chicken meat. The fresh chicken meat was subjected to the SC-CO2 at 14 MPa and 45°C for 40 min and was stored at 4°C for 0, 3, and 7 days. The obtained results indicated that the treatment with SC-CO2 significantly decreased the total plate count and, yeast and mould count from log10 5.90 to 2.00 CFU/g and from log10 5.02 to 2.00 CFU/g at day 7 of storage, respectively. The values of pH, cooking loss, and water holding capacity were not affected by the treatment. The results revealed that the SC-CO2 -treated samples displayed harder texture, higher lightness and yellowness, and lower redness. In addition, lipid peroxidation of SC-CO2 and control samples resulted in values of 1.9 and 0.5 MDA/mg of meat at day 7 of storage time and did not significantly change in the rest of the evaluation days. In summary, the application of SC-CO2 was capable of enhancing the microbial quality and certain physicochemical attributes. However, alteration of certain parameters of SC-CO2 might enhance the overall meat quality.
As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker's yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to obtain fermented brown rice flour (FBRF). The FBRF was added to white rice flour at 0%, 10%, 20%, 30%, 40% and 50% levels to prepare steamed rice bread. Based on the sensory evaluation test, steamed rice bread containing 40% FBRF had the highest overall acceptability score. Thus, pasting properties of the composite rice flour, rheological properties of its batter, volume and texture properties of its steamed bread were determined. The results showed that peak viscosity of the rice flour containing 40% FBRF was significantly increased, whereas its breakdown, final viscosity and setback significantly decreased. Viscous, elastic and complex moduli of the batter having 40% FBRF were also significantly reduced. However, volume, specific volume, chewiness, resilience and cohesiveness of its steamed bread were significantly increased, while hardness and springiness significantly reduced in comparison to the control. These results established the effectiveness of yeast fermentation in reducing the detrimental effects of bran on the sensory properties of steamed white rice bread and encourage the usage of brown rice flour to enhance the quality of rice products.
Bioprotein is one of the useful products obtained from biotechnology invention. It is a promising replacement for the commercial fish feed supplement. In this study, the enrichment of the bioprotein content after solid state fermentation using palm kernel cake and seaweed by the white rot fungus: Phanerochaete chrysoporium and yeast: Candida utilis was carried out. The growth media components were selected from 11 types of media using Plackett-Burman design (hereinafter PBD) and were optimized by one-factor-at-a-time (OFAT) method with bioprotein concentration (mg/g) as the response. From the screening result using PBD, three media components, namely K2HPO4, CuSO4.5H2O and MnSO4.H2O were selected for further optimization using OFAT method because of their positive contributions to the response. The final results showed that 5.0 g/L K2HPO4, 3.0 g/L CuSO4.5H2O and 0.1 g/L MnSO4.H2O were there to be the optimum media constituents with 9.0 g/L, MgSO4.7H2O, 0.1 g/L, CaCl2.H2O, 3.0 g/L FeSO4.7H2O and 3.0 g/L peptone as fixed compositions. At this optimum concentration, the protein increment of 11% was observed as compared to the results determined in the screening using PBD. The study revealed the benefits of using mixed cultures in improving the protein concentrations which can be used as nutritious fish feed.
Plants biosynthesize a great diversity of biologically active small molecules of interest for fragrances, flavors, and pharmaceuticals. Among specialized metabolites, terpenoids represent the greatest molecular diversity. Many terpenoids are very complex, and total chemical synthesis often requires many steps and difficult chemical reactions, resulting in a low final yield or incorrect stereochemistry. Several drug candidates with terpene skeletons are difficult to obtain by chemical synthesis due to their large number of chiral centers. Thus, biological production remains the preferred method for industrial production for many of these compounds. However, because these chemicals are often found in low abundance in the native plant, or are produced in plants which are difficult to cultivate, there is great interest in engineering increased production or expression of the biosynthetic pathways in heterologous hosts. Although there are many examples of successful engineering of microbes such as yeast or bacteria to produce these compounds, this often requires extensive changes to the host organism's metabolism. Optimization of plant gene expression, post-translational protein modifications, subcellular localization, and other factors often present challenges. To address the future demand for natural products used as drugs, new platforms are being established that are better suited for heterologous production of plant metabolites. Specifically, direct metabolic engineering of plants can provide effective heterologous expression for production of valuable plant-derived natural products. In this review, our primary focus is on small terpenoids and we discuss the benefits of plant expression platforms and provide several successful examples of stable production of small terpenoids in plants.
Introduction: Honey has potent bactericidal activity against many pathogenic organisms, including various Gram-negative and Gram-positive bacteria. This study aimed to determine the antimicrobial effect of Malaysian honey against different species of human pathogens using optimized honey broth media. Materials and Methods: The antimicrobial activity of honey against standard strains of Gram-negative and Grampositive bacteria and yeast was tested in vitro by the broth dilution method using 10%-100% w/v concentrations prepared in tryptic soy broth. Results: Streptococcus pyogenes was the most sensitive pathogen, it was completely inhibited by 30% honey broth medium. The most resistant were E. faecalis, S. aureus and MRSA, but they were all completely inhibited by 80% honey broth medium. Conclusion: Honey is shown to possess antimicrobial activity against human Gram-positive and negative medically important bacteria.
Red pitaya juice (RPJ) was subjected to UV-C irradiation and the potential of UV as a pasteurization tool for reducing microbial load in pitaya juice was evaluated. Effectiveness of the hurdle concept, i.e. addition of citric acid (CA) and dimethyl dicarbonate (DMDC) was also studied. Total plate counts (TPC) and yeast and mould counts (YMC) achieved 2.43 log₁₀ and 2.7 log₁₀ reductions respectively after exposure to UV irradiation. Addition of the CA (0.5 - 2.0%) and dimethyl dicarbonate (DMDC) (5 - 20 µL/100mL) to pitaya juice reduced the microbial loads, with 1.5% CA and 15 µL/100mL DMDC being the most effective concentrations. Addition of CA and DMDC into RPJ prior to UV treatment achieved significantly higher microbial reduction compared to UV alone, which were 4.12 log ₁₀ and 4.14 log₁₀ reductions for TPC and for YMC, respectively.
In industry, the yeast Rhodotorula mucilaginosa is commonly used for the production of carotenoids. The production of carotenoids is important because they are used as natural colorants in food and some carotenoids are precursors of retinol (vitamin A). However, the identification and molecular characterization of the carotenoid pathway/s in species belonging to the genus Rhodotorula is scarce due to the lack of genomic information thus potentially impeding effective metabolic engineering of these yeast strains for improved carotenoid production. In this study, we report the isolation, identification, characterization and the whole nuclear genome and mitogenome sequence of the endophyte R. mucilaginosa RIT389 isolated from Distemonanthus benthamianus, a plant known for its anti-fungal and antibacterial properties and commonly used as chewing sticks. The assembled genome of R. mucilaginosa RIT389 is 19 Mbp in length with an estimated genomic heterozygosity of 9.29%. Whole genome phylogeny supports the species designation of strain RIT389 within the genus in addition to supporting the monophyly of the currently sequenced Rhodotorula species. Further, we report for the first time, the recovery of the complete mitochondrial genome of R. mucilaginosa using the genome skimming approach. The assembled mitogenome is at least 7,000 bases larger than that of Rhodotorula taiwanensis which is largely attributed to the presence of large intronic regions containing open reading frames coding for homing endonuclease from the LAGLIDADG and GIY-YIG families. Furthermore, genomic regions containing the key genes for carotenoid production were identified in R. mucilaginosa RIT389, revealing differences in gene synteny that may play a role in the regulation of the biotechnologically important carotenoid synthesis pathways in yeasts.
Extremely low temperatures present various challenges to life that include ice formation and effects on metabolic capacity. Psyhcrophilic microorganisms typically have an array of mechanisms to enable survival in cold temperatures. In this study, we sequenced and analysed the genome of a psychrophilic yeast isolated in the Antarctic region, Glaciozyma antarctica. The genome annotation identified 7857 protein coding sequences. From the genome sequence analysis we were able to identify genes that encoded for proteins known to be associated with cold survival, in addition to annotating genes that are unique to G. antarctica. For genes that are known to be involved in cold adaptation such as anti-freeze proteins (AFPs), our gene expression analysis revealed that they were differentially transcribed over time and in response to different temperatures. This indicated the presence of an array of adaptation systems that can respond to a changing but persistent cold environment. We were also able to validate the activity of all the AFPs annotated where the recombinant AFPs demonstrated anti-freeze capacity. This work is an important foundation for further collective exploration into psychrophilic microbiology where among other potential, the genes unique to this species may represent a pool of novel mechanisms for cold survival.
The tooth provides a non-shedding surface ideal for microbial and plaque accumulation. Despite being exposed to regular environmental perturbations, the microbial composition and proportions in the plaque often remains in homeostasis and is relatively stable over time. Supragingival plaque sampled from various sites on the tooth surface was pooled and conventionally analyzed for its microbial constituent. Classification of microbial isolates was made based on the characteristics exhibited by the growth colonies, Gram-stained cells, as well as biochemical reactions using the API Identification System kit. Observation was also made of the colony forming units on both non-selective and selective agar culture plates. A variety of bacteria, both of the facultative and anaerobic types, were isolated from the supragingival plaque of the Malaysian population. Among those found to predominate the supragingival plaque include the Gram positive and Gram negative cocci and rods from the genera Streptococcus, Staphylococcus, Actinomyces, Fusobacterium, Corynebacterium, Clostridium, Bacteroides, Veilonella and Lactobacillus. In addition, yeast within the genus Candida was also isolated from the plaque samples.
Antifreeze proteins (AFPs) are specific proteins, glycopeptides, and peptides made by different organisms to allow cells to survive in sub-zero conditions. AFPs function by reducing the water's freezing point and avoiding ice crystals' growth in the frozen stage. Their capability in modifying ice growth leads to the stabilization of ice crystals within a given temperature range and the inhibition of ice recrystallization that decreases the drip loss during thawing. This review presents the potential applications of AFPs from different sources and types. AFPs can be found in diverse sources such as fish, yeast, plants, bacteria, and insects. Various sources reveal different α-helices and β-sheets structures. Recently, analysis of AFPs has been conducted through bioinformatics tools to analyze their functions within proper time. AFPs can be used widely in various aspects of application and have significant industrial functions, encompassing the enhancement of foods' freezing and liquefying properties, protection of frost plants, enhancement of ice cream's texture, cryosurgery, and cryopreservation of cells and tissues. In conclusion, these applications and physical properties of AFPs can be further explored to meet other industrial players. Designing the peptide-based AFP can also be done to subsequently improve its function.
The interest in utilizing algae for wastewater treatment has been increased due to many advantages. Algae-wastewater treatment system offers a cost-efficient and environmentally friendly alternative to conventional treatment processes such as electrocoagulation and flocculation. In this biosystem, algae can assimilate nutrients in the wastewater for their growth and simultaneously capture the carbon dioxide from the atmosphere during photosynthesis resulting in a decrease in the greenhouse gaseousness. Furthermore, the algal biomass obtained from the treatment process could be further converted to produce high value-added products. However, the recovery of free suspended algae from the treated effluent is one of the most important challenges during the treatment process as the current methods such as centrifugation and filtration are faced with the high cost. Immobilization of algae is a suitable approach to overcome the harvesting issue. However, there are some drawbacks with the common immobilization carriers such as alginate and polyacrylamide related to low stability and toxicity, respectively. Hence, it is necessary to apply a new carrier without the mentioned problems. One of the carriers that can be a suitable candidate for the immobilization is zeolite. To date, various types of zeolite have been used for the immobilization of cells of bacteria and yeast. If there is any possibility to apply them for the immobilization of algae, it needs to be considered in further studies. This article reviews cell immobilization technique, biomass immobilization onto zeolites, and algal immobilization with their applications. Furthermore, the potential application of zeolite as an ideal carrier for algal immobilization has been discussed.
Catheter-related bloodstream infections caused by Kodamaea ohmeri are generally not considered due to the relative scarcity of reported cases. This is a case of an 85-year-old man with poorly controlled diabetes mellitus who was initially admitted to our hospital for diabetic ketoacidosis. An internal jugular catheter was inserted as part of the initial management. A week later the patient developed a temperature spike and a yeast identified as Kodamaea ohmeri by ID 32 C (bioMérieux, France) was isolated from both his central and peripheral blood cultures. The catheter was removed and the patient was treated with fluconazole despite the organism’s relatively high minimum inhibitory concentration (2 μg/mL) to this antifungal. The fungemia resolved following a 2-weeks course of fluconazole.
Evaluation on the physicochemical and sensory properties of wheat flour doughnuts substituted with banana flour (BF) was investigated. Wheat flour was substituted with green banana (Musa paradisiaca var. Awak) flour at 0% (control), 10%, 20% and 30% levels in yeast-raised doughnut prepared by the straight dough method. Chemical (moisture, fat, protein, ash, carbohydrate, crude fibre, total dietary fibre and caloric content), physical (volume, specific volume and colour) and sensory evaluation were conducted on all samples. Chemical analyses result indicated a higher percentage of total dietary fibre and caloric content in doughnut substituted with BF than the control. Colour evaluation showed that the dough, crust and crumb of doughnut with BF ranged from 68.97 ± 0.59 – 84.78 ± 0.16 (red – yellow quadrant). The change from light to darker colour correlated with the amount of BF added. Results also showed that the volume and specific volume was significantly affected (p < 0.05) by levels of BF substituted. Doughnut substituted with 20% BF showed the highest score in overall acceptability (6.71 ± 1.40).
Pressure ulcers are commonly associated with microbial infections on the wounds which require an effective wound dressing for treatment. Thus far, the available silver dressing has shown tremendous result, however, it may cause argyria and complicate the internal organ function. Hence, our study aims to develop and characterize phomopsidione-loaded chitosan-polyethylene glycol nanocomposite hydrogel (C/PEG/Ph) as an antimicrobial dressing. Physically, the C/PEG/Ph hydrogel demonstrated a uniform light blue color, soft, flexible, and elastic, with no aggregation form. The evaluation via Fourier Transform Infrared (FTIR) exposed the C/PEG/Ph hydrogel has a notable shift towards lower frequency at 1600 and 1554 cm-1. For drug release test, the phomopsidione attained plateau at 24 h, with a total release of 67.9 ± 6.4% from the C/PEG/Ph hydrogel. There was a null burst release effect discovered throughout the experimental period. The C/PEG/Ph hydrogel showed significant results against all 4 Gram-negative bacteria and 1 yeast, with 99.99-100% reduction of microbial growth. The findings revealed that the C/PEG/Ph hydrogel can potentially act as an antimicrobial dressing for pressure ulcers.
The effect of storage time on the quality of ultraviolet-irradiated and thermally pasteurised pineapple juice was evaluated. The juices were irradiated with ultraviolet light (UV-C) at wavelength 254 nm (53.42 mJ/cm2, 4.918 s), thermally pasteurised at 800C for 10 minutes and stored at 40C for 13 weeks. There were significant changes in the total soluble solids, pH, titratable acidity and turbidity of UV-irradiated juice during storage, whereas for the same quality attributes of thermally pasteurised juice remained stable throughout the storage time. There were no significant changes in total phenolics for both treatments throughout the storage period. Other quality parameters (ascorbic acid, colour L, hue angle and chroma) were significantly affected by the storage time. Regarding the microbiological analysis, the total plate counts and yeast and mould counts of the UV-irradiated juice increased gradually throughout the 13 weeks of storage while these parameters remained unchanged in the thermally pasteurised juice with almost no microorganism growth. UV-irradiated pineapple juice preserved better quality attributes (TSS, pH, titratable acidity, ascorbic acid, turbidity, total phenolic, L (lightness), hue angle and chroma) than the thermal pasteurised juice during the storage time. Hence, UV irradiation has great potential as an alternative technology to thermal pasteurisation in producing products of high nutritive values.
Widespread food poisoning due to microbial contamination has been a major concern for the food industry, consumers and governing authorities. This study is designed to determine the levels of fungal contamination in edible bird nests (EBNs) using culture and molecular techniques. Raw EBNs were collected from five house farms, and commercial EBNs were purchased from five Chinese traditional medicine shops (companies A-E) in Peninsular Malaysia. The fungal contents in the raw and commercial EBNs, and boiled and unboiled EBNs were determined. Culturable fungi were isolated and identified. In this study, the use of these methods revealed that all EBNs had fungal colony-forming units (CFUs) that exceeded the limit set by Standards and Industrial Research Institute of Malaysia (SIRIM) for yeast and moulds in EBNs. There was a significant difference (p < 0.05) in the number of types of fungi isolated from raw and commercial EBNs, but no significant difference in the reduction of the number of types of fungi after boiling the EBNs (p > 0.05). The types of fungi isolated from the unboiled raw EBNs were mainly soil, plant and environmental fungi, while the types of fungi isolated from the boiled raw EBNs, unboiled and boiled commercial EBNs were mainly environmental fungi. Aspergillus sp., Candida sp., Cladosporium sp., Neurospora sp. and Penicillum sp. were the most common fungi isolated from the unboiled and boiled raw and commercial EBNs. Some of these fungi are mycotoxin producers and cause opportunistic infections in humans. Further studies to determine the mycotoxin levels and methods to prevent or remove these contaminations from EBNs for safe consumption are necessary. The establishment and implementation of stringent regulations for the standards of EBNs should be regularly updated and monitored to improve the quality of the EBNs and consumer safety.
This study was performed to evaluate the antifungal activities of methanolic fractions from the stem bark of Entada spiralis Ridl. against human dermatophytes and yeast-like fungus in vitro. Three types of human dermatophyte, Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102 and Trichophyton tonsurans ATCC 28942, and one yeast-like fungus, Candida glabrata ATCC 66032, were tested against the methanolic fractions labelled FA1, FA4 and FA5. T. mentagrophytes, T. tonsuran and M. gypseum were susceptible to all tested fractions in a concentration-dependent manner whereas C. glabrata was resistant. Fraction FA1 at a concentration of 400 mg/mL was found to exhibit the highest antifungal activity with the inhibition zone diameter of 22 mm (T. mentagrophytes). This fraction showed a minimum inhibitory concentration MIC of 0.097 mg/mL while the MIC value for the fraction FA4 and fraction FA5 was 3.12 mg/ml and 1.56 mg/ml respectively. Agar overlay bioautography assay results showed that most of the bioactive compounds were found in the fraction FA1. Based on these findings, it can be concluded that the stem bark extracts of E. spiralis can be a future source of potent natural antimicrobial drugs for superficial skin diseases.
Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.
Cancers of the breast and cervix made up 30.4% and 12% of all cancer cases in Malaysia. Thus screening for reproductive organ cancers as women approached menopause becomes exceedingly important. The study reports the baseline assessment tests of 495 disease free urban Malaysian women aged 45 years and above who volunteered in a healthy lifestyle intervention study. The sample comprised of 58.0% premenopaused and 42.0% postmenopaused women with an average age of 51.27±5.35 years old. Over two thirds were Chinese followed by Malays and Indians. Overall, abnormal Pap smears were seen in 7.6% comprising of 1.3% cervical intraepithelial neoplasia (CIN), 6.1% human papilloma virus (HPV) infection and 0.2% atypical squmous cells of undetermined significances (ASCUS). Yeast and other infections were found in 6.9% and 1.9% respectively. Comparatively, postmenopausal women had a 2.8 fold higher cancerous changes whereas premenopausal women had a higher infection rate, 11.8% vs. 4.7% respectively (p=0.024) with comparable HPV infection rates in both. This study found 1.3% had breast cancer (BC) with 3.6% requiring a biopsy while 3.4% needed regular follow up. Postmenopaused women had more abnormal mammograms (p