Free Radical Scavenging Activity of Aqueous and Ethanolic Extract of Brassica oleracea L. var. italica

In this study, antioxidant activities of aqueous and ethanolic extracts of Brassica oleracea L. var. italica were investigated. The antioxidant properties of both extracts of Brassica oleracea L. var. italica were evaluated using different antioxidant tests, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide radical scavenging, inhibition of microsomal lipid peroxidation, reduction of power, and metal ion chelating activities. Inhibition of superoxide scavenging by aqueous and ethanolic extracts showed an IC₅₀ of 0.93 and 0.25 mg/ml, respectively. Metal ion chelation showed an IC₅₀ of 0.35 mg/ml of both the extracts and was equipotent to positive control, ethylenediamine tetra-acetic acid. The ethanolic extract of Brassica oleracea L. var. italica exhibited higher antioxidant activity in DPPH radical and superoxide anion scavenging than that of aqueous extract. The results obtained in the in vitro models clearly suggest that, Brassica oleracea L. var. italica is a natural source for antioxidants, which could serve as a nutraceutical with potential applications in reducing the level of oxidative stress and related health benefits. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models.     

Prevalence and resistance to antibiotics for Aeromonas species from retail fish in Malaysia

A total of 87 market fish samples representing five types of fish were evaluated for the presence of Aeromonas spp. Of the samples examined, 69%, 55%, 11.5% and 2.3% harbored Aeromonas spp., A. veronii biovar sobria, A. hydrophila and A. caviae, respectively. The 60 isolated Aeromonas spp. strains were further examined for hemolytic activity, resistance to antimicrobial agents and presence of plasmids. Hemolytic activity varied widely among the isolated strains. Though all the isolates demonstrated resistance to three or more of the antibiotics tested, all were susceptible to ceptazidime. Thirty-four (56.7%) of the sixty isolates harbored plasmids, with sizes ranging from 2.3 to 15.7 kb. These results indicate that hemolytic, multiple antibiotic resistant and genetically diverse aeromonads are easily recovered from fish in this region.     

Essential oils of Zingiber officinale var. rubrum Theilade and their antibacterial activities

The essential oils obtained by hydrodistilation of the leaves and rhizomes of Zingiber officinale var. rubrum Theilade were analysed by capillary GC and GC–MS. Forty-six constituents were identified in the leaf oil, while 54 were identified in the oil from the rhizomes. The leaf oil was clearly dominated by β-caryophyllene (31.7%), while the oil from the rhizomes was predominantly monoterpenoid, with camphene (14.5%), geranial (14.3%), and geranyl acetate (13.7%) the three most abundant constituents. The evaluation of antibacterial activities using the micro-dilution technique revealed that both the leaf and rhizome oils were moderately active against the Gram-positive bacteria Bacilluslicheniformis, Bacillus spizizenii and Staphylococcus aureus, and the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Pseudomonas stutzeri.     

Thermal Behavior of Selected Starches in Presence of Other Food Ingredients Studied by Differential Scanning Calorimetery (DSC)–Review

ABSTRACT: This review article highlights the thermal behaviors of selected starches that were studied using differential scanning calorimetery (DSC) with data shown in various research publications. The starches of sago, potato, sweet potato, cassava, yam, and corn are included in this overview. Our examinations indicate that thermal properties are highly affected by the type of starch, its amylose/amylopectin content, and the presence of other food ingredients such as sugar, sodium chloride, water, milk, hydrocolloids, and meat. When the heating temperatures of the starches were increased, the DSC measurements also showed an increase in the temperatures of the gelatinization (onset [T_o], peak [T_p], and conclusion [T_c]). This may be attributed to the differences in the degree of crystallinity of the starch, which provides structural stability and makes the granule more resistant to gelatinization.     

Enhancement of Red Pigment Production by Monascus purpureus FTC 5391 through Retrofitting of Helical Ribbon Impeller in Stirred-Tank Fermenter

The possibility of using a novel proximity type half-pitched, double-flight helical ribbon impeller (HRI) for the improvement of red pigment production by Monascus purpureus FTC5391 was investigated in a 2-L stirred-tank fermenter (STF). For comparison, the fermentations were also carried out in STF equipped with the industrial standard six-bladed Rushton turbines (RT). The selection of aeration and agitation strategies in STF were based on possible attainable oxygen transfer at the start of fermentation using derived empirical power law model to predict the initial volumetric oxygen transfer coefficient (k _L a). The final pigment concentration, yield, and productivity obtained in optimized fermentation employing a single HRI agitated at 250 rpm and air flow rate of 2.25 L/min (1.5 vvm) was 24.36 UA₅₀₀, 0.47 UA₅₀₀/g glucose, and 0.20 UA₅₀₀/h, respectively. These values were about 76%, 78%, and 96% higher than those obtained in STF fitted with RT, respectively. In terms of impeller power consumption, the HRI system was favorable for batch cultivation of M. purpureus as pigment yield per energy invested was 2.5 times higher than the RT.     

Isolation,purification and characterisation of angiotensin I‐converting enzyme–inhibitory peptides derived from catfish (Clarias batrachus) muscle protein thermolysin hydrolysates

The angiotensin I‐converting enzyme (ACE)‐inhibitory activities of catfish (Clarias batrachus) muscle protein hydrolysates were investigated. Thermolytic digests of C. batrachus sarcoplasmic and myofibrillar proteins exhibited inhibitory activity towards ACE and were purified with the aim of ultrafiltration, gel filtration and reversed‐phase high‐performance liquid chromatography (RP‐HPLC). The amino acid sequences of hydrolysates with the highest ACE‐inhibitory activities were determined using electrospray quadrupole time‐of‐flight tandem mass spectrometry (ESI‐TOFQ MS/MS). The sequences of GPPP (IC₅₀ = 0.86 μm ) and IEKPP (IC₅₀ = 1.2 μm ) corresponding to the fragments 986–989 and 441–445 of myosin‐I heavy chain were identified for the sarcoplasmic and myofibrillar protein hydrolysates, respectively. Peptide GPPP exhibited a mixed‐type inhibition whereas peptide IEKPP could only bind to the active sites of ACE. The results demonstrate that hydrolysates of C. batrachus muscle proteins obtained by thermolysin may contain bioactive peptides.     

Oil palm bunch ripeness classification using fluorescence technique

Oil palm is Malaysia’s major agriculture product and it covers approximately 5 million hectares of Malaysia’s land. Limited land resources have been an important factor that motivated the need to increase oil extraction rate (OER). OER of oil palm fresh fruit bunches (FFB) depends highly on their maturity stage. The ripe oil palm FFB will produce high OER while the under ripe and over ripe oil palm FFB will produce less oil. Thus, this paper presents a method of classification between oil palm FFB into ripe, under-ripe and over-ripe categories. This research was done at an oil palm plantation in peninsular Malaysia. A total of two-hundred and ten oil palm FFB that consist of seventy bunches for each category of under-ripe, ripe and over-ripe had been used. Each bunch was scanned ten times randomly with a hand-held multi-parameter fluorescence sensor called Multiplex®3. The parameter measured was the Blue-to-Red Fluorescence Ratio (BRR_FRF) obtained from blue-green (447 nm) and far-red (685 nm) emission signal by using ultraviolet (UV) light emitting diode as excitation light source. The novel contribution of this research is to prove that the oil palm FFB maturity can be determined using the Blue-to-Red Fluorescence ratio index. This is based to our finding of a significant difference among the three categories of ripeness based on the parameter. Classification and Regression Tree (C&RT) method was proposed in this paper. Hundred-fifty samples were used to develop the model by trained it using C&RT method and the remaining sixty samples for the test component. By using the C&RT method, the results show the best accuracy of overall testing classification is 90%. This research will be useful for future development of non-destructive, automatic and real time oil palm FFB grading system.     

Potent Antidiabetic Activity and Metabolite Profiling of Melicope Lunu‐ankenda Leaves

Diabetes mellitus is normally characterized by chronic hyperglycemia associated with disturbances in the fat, carbohydrate, and protein metabolism. There is an increasing trend of using natural products instead of synthetic agents as alternative therapy for disorders due to their fewer side effects. In this study, antidiabetic and antioxidant activities of different Melicope lunu‐ankenda (ML) ethanolic extracts were evaluated using inhibition of α‐glucosidase and 2,2‐diphenyl‐l‐picrylhydrazyl (DPPH) radicals scavenging activity, respectively; whereas, proton nuclear magnetic resonance (¹H NMR) and ultra‐high performance liquid chromatography‐tandem mass spectrometric (UHPLC‐MS/MS) techniques were used for metabolite profiling of ML leaf extracts at different concentrations of ethanol and water. Sixty percent of ethanolic ML extract showed highest inhibitory effect against α‐glucosidase enzyme (IC₅₀ of 37 μg/mL) and DPPH scavenging activity (IC₅₀ of 48 μg/mL). Antidiabetic effect of ML extracts was also evaluated in vivo and it was found that the high doses (400 mg/Kg BW) of ML extract exhibited high suppression in fasting blood glucose level by 62.75%. The metabolites responsible for variation among ML samples with variable ethanolic levels have been evaluated successfully using ¹H‐NMR–based metabolomics. The principal component analysis (PCA) and partial least squares(PLS) analysis scores depicted clear and distinct separations into 4 clusters representing the 4 ethanolic concentrations by PC1 and PC2, with an eigenvalue of 69.9%. Various ¹H‐NMR chemical shifts related to the metabolites responsible for sample difference were also ascribed. The main bioactive compounds identified attributing toward the separation included: isorhamnetin, skimmianine, scopoletin, and melicarpinone. Hence, ML may be used as promising medicinal plant for the development of new functional foods, new generation antidiabetic drugs, as a single entity phytomedicine or in combinational therapy.