Physicochemical and sensory characteristic changes in fortified peanut spreads after 3 months of storage at different temperatures

Three amino acid-balanced, vitamin- and mineral-fortified peanut spreads were stored at 4, 23, and 40 degrees C for 3 months. These were 69.6% peanut/19% soybean-40.5% fat, 61.9% peanut/19% soybean-44.5% fat, and 74.1% peanut/14% nonfat dry milk (NFDM)-40% fat. The peanut spreads were fortified with vitamin A, thiamin, riboflavin, vitamin B(6), vitamin C, calcium, and iron to provide 33.3% of the Recommended Dietary Allowances for children. Water-soluble vitamins were quite stable in deaerated peanut spreads. The antioxidant activity of phytochemicals in soybean prevented vitamin A degradation in soy-containing spreads, whereas the NFDM spread lost 70% of the initial content. Instron analysis detected major changes in texture when peanut spreads were stored at 40 degrees C, suggesting that the polymorphic form of lipid transformed and the proper crystallization of stabilizer was destroyed. Panelists did not detect the texture changes in peanut spreads stored at different temperatures. At 40 degrees C, the primary deteriorative changes in sensory quality were increased browning and the development of "soybean" and "oxidized" flavors as well as decreased "roasted peanutty" flavor.     

Lipoxygenase from banana leaf: purification and characterization of an enzyme that catalyzes linoleic acid oxygenation at the 9-position

The objective of the present study was to purify and characterize the lipoxygenase (LOX) from banana leaf (Giant Cavendishii, AAA), an unutilized bioresource. LOX was extracted, isolated, and purified 327-fold using 25-50% saturation of ammonium sulfate fractionation, hydroxyapatite column separation, and gel filtration on Superdex 200. The molecular mass of the purified LOX was 85 kDa, K(m) was 0.15 mM, and V(max) was 2.4 microM/min.mg using linoleic acid as substrate. Triton X-100 was required in the extraction medium; otherwise, no LOX activity was detected. LOX activity increased with the concentration of Triton X-100 with an optimum at 0.1%. The optimal pH of the purified LOX from banana leaf was 6.2, and optimal temperature was 40 degrees C. The LOX showed the highest reactivity toward 18:2 followed by 18:3 and 20:4. A very low reaction rate was observed toward 20:5 and 22:6. On the basis of retention time in normal phase HPLC, the products of 18:2 or 18:3 catalyzed by purified LOX were hydroperoxyoctadecadienoic acid or hydroperoxyoctadecatrienoic acid. It seems that 9-LOX is the predominant enzyme in banana leaf. Banada leaf dried at 110 degrees C for 2 h developed algal aroma. Banana leaf extract stored at 10 degrees C for 12 h formed an oolong tea-like flavor. Banana leaf extract reacted with 18:2 or soybean oil pretreated with bacterial lipase produced green and melon-like aroma, whereas the same reaction with 18:3 produced a sweet, fruity, cucumber-like flavor note.     

A new approach to selecting a regionalized design hyetograph by principal component analysis and analytic hierarchy process

Designing storm hyetographs is the essential element of hydrologic modeling analysis and storm water drainage design. In order to reasonably use storm hyetograph design in an un-gauged area, a regional representative hyetograph from an alternative and uniform area must be found. A new approach is proposed in this study to select a regional design storm hyetograph using principal component analysis (PCA) and analytic hierarchy process (AHP). The proposed approach combines both PCA and cluster analysis techniques. Furthermore, the AHP method is also used to establish the regional design hyetograph. A case study applied in the area of northern Taiwan shows that our method can successfully categorize the area into three homogenous zones. A representative regional hyetograph can be obtained by selecting the largest priority vector or by the weighted average of rain gauges in each zone.     

Glutamate-activated chloride channels: Unique fipronil targets present in insects but not in mammals

Selectivity to insects over mammals is one of the important characteristics for a chemical to become a useful insecticide. Fipronil was found to block cockroach GABA receptors more potently than rat GABA_A receptors. Furthermore, glutamate-activated chloride channels (GluCls), which are present in cockroaches but not in mammals, were very sensitive to the blocking action of fipronil. The IC₅₀s of fipronil block were 30 nM in cockroach GABA receptors and 1600 nM in rat GABA_A receptors. Moreover, GluCls of cockroach neurons had low IC₅₀s for fipronil. Two types of glutamate-induced chloride current were observed: desensitizing and non-desensitizing, with fipronil IC₅₀s of 800 and 10 nM, respectively. We have developed methods to separately record these two types of GluCls. The non-desensitizing and desensitizing currents were selectively inhibited by trypsin and polyvinylpyrrolidone, respectively. In conclusion, in addition to GABA receptors, GluCls play a crucial role in selectivity of fipronil to insects over mammals. GluCls form the basis for development of selective and safe insecticides.     

SV2 is the protein receptor for botulinum neurotoxin A

How the widely used botulinum neurotoxin A (BoNT/A) recognizes and enters neurons is poorly understood. We found that BoNT/A enters neurons by binding to the synaptic vesicle protein SV2 (isoforms A, B, and C). Fragments of SV2 that harbor the toxin interaction domain inhibited BoNT/A from binding to neurons. BoNT/A binding to SV2A and SV2B knockout hippocampal neurons was abolished and was restored by expressing SV2A, SV2B, or SV2C. Reduction of SV2 expression in PC12 and Neuro-2a cells also inhibited entry of BoNT/A, which could be restored by expressing SV2 isoforms. Finally, mice that lacked an SV2 isoform (SV2B) displayed reduced sensitivity to BoNT/A. Thus, SV2 acts as the protein receptor for BoNT/A.     

Mechanism of decay resistance of heartwood extracts from Acacia confusa against the brown-rot fungus Laetiporus sulphureus

Acacia confusa is an indigenous plantation species in Taiwan, and its heartwood has excellent decay resistance capability. The aim of this study is to investigate the resistance mechanisms of heartwood extracts from A. confusa against Laetiporus sulphureus (brown-rot). Results from wood block decay resistance tests indicate that aqueous crude extract and its three soluble fractions can significantly decrease the weight loss of wood blocks caused by L. sulphureus. However, none of the extracts can inhibit the growth of L. sulphureus on agar plate test. The performance of decay resistance from three soluble fractions is consistent with their antioxidant activities (DPPH free radical scavenging activity, reducing power and ferrous ion chelating ability). 3,4-Dihydroxybenzoic acid (3,4-DHBA), the compound present in three soluble fractions, exhibited excellent antioxidant activities and was proven to have excellent decay resistance ability against L. sulphureus. These findings suggest that 3,4-DHBA may be responsible for the inhibition of hydroxyl radical formation from Fenton reaction caused by L. sulphureus. Thus, 3,4-DHBA has good potential to be used as a novel and environmentally benign wood preservative.     

Oat Prevents Obesity and Abdominal Fat Distribution, and Improves Liver Function in Humans

Obesity is associated with a great diversity of diseases including non-alcoholic fatty liver disease. Our recent report suggested that oat, rich in beta-glucan, had a metabolic-regulating and liver-protecting effect in an animal model. In this study, we performed a clinical trial to further confirm the effect of oat. Subjects with BMI ≧27 and aged 18–65, were randomly divided into a control (n?=?18) and an oat-treated (n?=?16) group, taking a placebo or beta glucan-containing oat cereal, respectively, for 12 weeks. Our data showed that consumption of oat reduced body weight, BMI, body fat and the waist-to-hip ratio. Profiles of hepatic function, including AST, but especially ALT, were useful resources to help in the evaluation of the liver, since both showed decrements in patients with oat consumption. Nevertheless, anatomic changes were still not observed by ultrasonic image analysis. Ingestion of oat was well tolerated and there was no adverse effect during the trial. In conclusion, consumption of oat reduced obesity, abdominal fat, and improved lipid profiles and liver functions. Taken as a daily supplement, oat could act as an adjuvant therapy for metabolic disorders.     

Towards the Small and the Beautiful: A Small Dibromotyrosine Derivative from Pseudoceratina sp. Sponge Exhibits Potent Apoptotic Effect through Targeting IKK/NFκB Signaling Pathway

A dibromotyrosine derivative, (1′R,5′S,6′S)-2-(3′,5′-dibromo-1′,6′-dihydroxy-4′-oxocyclohex-2′-enyl) acetonitrile (DT), was isolated from the sponge Pseudoceratina sp., and was found to exhibit a significant cytotoxic activity against leukemia K562 cells. Despite the large number of the isolated bromotyrosine derivatives, studies focusing on their biological mechanism of action are scarce. In the current study we designed a set of experiments to reveal the underlying mechanism of DT cytotoxic activity against K562 cells. First, the results of MTT cytotoxic and the annexin V-FITC/PI apoptotic assays, indicated that the DT cytotoxic activity is mediated through induction of apoptosis. This effect was also supported by caspases-3 and -9 activation as well as PARP cleavage. DT induced generation of reactive oxygen species (ROS) and the disruption of mitochondrial membrane potential (MMP) as indicated by flow cytometric assay. The involvement of ROS generation in the apoptotic activity of DT was further corroborated by the pretreatment of K562 cells with N-acetyl-cysteine (NAC), a ROS scavenger, which prevented apoptosis and the disruption of MMP induced by DT. Results of cell-free system assay suggested that DT can act as a topoisomerase II catalytic inhibitor, unlike the clinical anticancer drug, etoposide, which acts as a topoisomerase poison. Additionally, we found that DT treatment can block IKK/NFκB pathway and activate PI3K/Akt pathway. These findings suggest that the cytotoxic effect of DT is associated with mitochondrial dysfunction-dependent apoptosis which is mediated through oxidative stress. Therefore, DT represents an interesting reference point for the development of new cytotoxic agent targeting IKK/NFκB pathway.