Search

Response surface methodology was applied to optimize protein content in Candida utilis grown in pineapple waste medium. A three-level full factorial design was used to develop a quantitative interpretation of mathematical models between the two variables studied, inoculum size 2.0-10.0% (v/v) and total soluble solids in medium (1-5 Brix) at 30 h fermentation time. Yeast cells were harvested, ruptured mechanically and the soluble extract was freeze-dried for determination of protein, vitamin-B, 5'-ribonucleotide and total sugar content. Maximum protein content in the yeast 66.61% (w/w) was obtained from the predicted optimum inoculum size of 7.83% (v/v) and Brix level of 3.02. Highest level of biomass, vitamin-B, 5'-ribonucleotide and total sugar content within the experimental region increased 216.8%, 17.5%, 38.0% and 60.8% respectively after optimization. A verification experiment, conducted at optimized protein content conditions produced values that were close to the predicted values, indicating the reliability of the model used.

Aim: The aim of this study was to evaluate the molecular mechanisms of Lactobacillus strains in improving ageing of the musculoskeletal system. Methods and Results: The anti‐ageing mechanism of three probiotics strains Lactobacillus fermentum DR9, Lactobacillus paracasei OFS 0291 and L. helveticus OFS 1515 were evaluated on gastrocnemius muscle and tibia of d‐galactose‐induced ageing rats. Upon senescence induction, aged rats demonstrated reduced antioxidative genes CAT and SOD expression in both bone and muscle compared to the young rats (P < 0·05). Strain L. fermentum DR9 demonstrated improved expression of SOD in bone and muscle compared to the aged rats (P < 0·05). In the evaluation of myogenesis‐related genes, L. paracasei OFS 0291 and L. fermentum DR9 increased the mRNA expression of IGF‐1; L. helveticus OFS 1515 and L. fermentum DR9 reduced the expression of MyoD, in contrast to the aged controls (P < 0·05). Protective effects of L. fermentum DR9 on ageing muscle were believed to be contributed by increased AMPK‐α2 expression. Among the osteoclastogenesis genes studied, TNF‐α expression was highly elevated in tibia of aged rats, while all three probiotics strains ameliorated the expression. Lactobacillus fermentum DR9 also reduced the expression of IL‐6 and TRAP in tibia when compared to the aged rats (P < 0·05). All probiotics treatment resulted in declined proinflammatory cytokines IL‐1β in muscle and bone. Conclusions: Lactobacillus fermentum DR9 appeared to be the strongest strain in modulation of musculoskeletal health during ageing. Significance and Impact of the Study: The study demonstrated the protective effects of the bacteria on muscle and bone through antioxidative and anti‐inflammatory actions. Therefore, L. fermentum DR9 may serve as a promising targeted anti‐ageing therapy. [ABSTRACT FROM AUTHOR]

Type III resistant starch (RS3) was produced from native sago starch using different processing conditions. Native sago starch contained 93.5% total starch, of which was 25.8% amylose and 67.7% amylopectin. A sample with the highest RS3 content (35.7%) was produced when the native sago starch was suspended in distilled water, gelatinised by autoclaving at 121°C for 1 h, followed by debranching with 20U pullulanase per g starch at 60°C for 24 h, autoclaved again at 121°C for 1 h before storage at 4°C for 24 h. The sago RS3 sample contained 54.0% amylose and 38.8% amylopectin. The powder had solubility, swelling power, water-holding and oil-holding capacity of 27.4%, 2.8g/g, 1.7g/g and 1.1g/g, respectively. Treatment of the sago RS3 with 0.5M HCl acid at 60°C for 24 h produced HCl-sago RS3 with 68.30% RS3 content. The solubility and swelling power of HCl-sago RS3 was 14.9% and 1.9g/g, respectively. Different processing conditions had significantly influenced the amount and properties of RS3 produced from sago starch. [ABSTRACT FROM AUTHOR]

Aims The study aimed to evaluate the effects of Mn2+ and Mg2+ on lactic acid production using response surface methodology and to further study their effects on interactions between the enzymes and substrates along the hexose monophosphate pathway using a molecular modelling approach. Methods and Results A rotatable central composite design matrix for lactic acid production was generated with two independent factors namely, manganese sulfate and magnesium sulfate. The second-order regression model indicated that the quadratic model was significant ( P < 0·05), suggesting that the model accurately represented the data in the experimental region. Three-dimensional response surface showed that lactic acid production was high along the region where the ratio of Mn SO4 to Mg SO4 was almost 1 : 1, justifying the need for both Mg2+ and Mn2+ to be present simultaneously in stimulating the production of lactic acid. Molecular docking simulation was performed on a total of 13 essential enzymes involved in the hexose monophosphate pathway for the production of lactic acid with four different conditions namely in the presence of Mg2+, Mn2+, both Mg2+ and Mn2+ and in the absence of metal ions. Results showed that the presence of both Mg2+ and Mn2+ within the binding site improved the binding affinity for substrates in five enzymes namely, glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate hydratase and pyruvate kinase. Conclusions Using response surface methodology and molecular modelling approach, we illustrated that Mg2+ and Mn2+ synergistically enhanced lactic acid production by Lactobacillus rhamnosus FTDC 8313 via affecting different stages of the hexose monophosphate pathway. Significance and Impacts of the Study Mg2+ and Mn2+ synergistically improved lactic acid production of Lact. rhamnosus via improved binding affinity of the enzyme-substrate along the hexose monophosphate pathway, instead of purely affecting growth as previously understood. [ABSTRACT FROM AUTHOR]

This study reports on the microbiological quality of fresh and laboratory prepared pitaya fruit juice compared this with those collected from street vendors in the Penang island of Malaysia. Additionally, the microbial growth patterns were monitored during extended storage for up to 7 days at 2 different temperature ranges (at 10°C and 25±1°C). Results revealed the presence and increase in the incidence of bacteria, yeasts and moulds in all the juice samples (fresh and stored). Except for Klebsiella pneumoniae all the other foodborne pathogens screened in this study such as: Staphylococcus aureus, Salmonella sp. and generic Escherichia coli were absent. Our results highlights and stresses the need to employ proper hygienic conditions during harvesting and processing stages of pitaya fruit or their juices to improve the overall microbial quality to ensure adequate safety for consumers. [ABSTRACT FROM AUTHOR]

The physical attributes (pH and colour), cooking yield, textural and mechanical properties (firmness, tensile and texture profiles analyses) and structural breakdown properties (multiple extrusion cell with added artificial saliva) of five yellow alkaline noodle (YAN) formulations were studied. Samples used were noodles with (a) typical formulation (control), (b) soy protein isolate (SPI), (c) soy protein isolate plus microbial transglutaminase enzyme (SPI/MTGase), (d) green banana pulp flour (GBPu) and (e) green banana peel flour (GBPe). Compared to other noodles SPI/MTGase noodle showed significantly (P < 0.05) higher values in terms of textural, mechanical and breakdown properties. Incorporating SPI, banana pulp and peel flours into the noodles had imposed some differences on most of the mechanical and textural parameters from the control YAN. However, these noodles could not be clearly distinguished in term of structural breakdown properties. [ABSTRACT FROM AUTHOR]